DAGCombiner.cpp revision ae4746b29a3f418dde0b8e2820019ec07303594e
1//===-- DAGCombiner.cpp - Implement a DAG node combiner -------------------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This pass combines dag nodes to form fewer, simpler DAG nodes. It can be run 11// both before and after the DAG is legalized. 12// 13// This pass is not a substitute for the LLVM IR instcombine pass. This pass is 14// primarily intended to handle simplification opportunities that are implicit 15// in the LLVM IR and exposed by the various codegen lowering phases. 16// 17//===----------------------------------------------------------------------===// 18 19#define DEBUG_TYPE "dagcombine" 20#include "llvm/CodeGen/SelectionDAG.h" 21#include "llvm/DerivedTypes.h" 22#include "llvm/LLVMContext.h" 23#include "llvm/CodeGen/MachineFunction.h" 24#include "llvm/CodeGen/MachineFrameInfo.h" 25#include "llvm/Analysis/AliasAnalysis.h" 26#include "llvm/Target/TargetData.h" 27#include "llvm/Target/TargetLowering.h" 28#include "llvm/Target/TargetMachine.h" 29#include "llvm/Target/TargetOptions.h" 30#include "llvm/ADT/SmallPtrSet.h" 31#include "llvm/ADT/Statistic.h" 32#include "llvm/Support/CommandLine.h" 33#include "llvm/Support/Debug.h" 34#include "llvm/Support/ErrorHandling.h" 35#include "llvm/Support/MathExtras.h" 36#include "llvm/Support/raw_ostream.h" 37#include <algorithm> 38using namespace llvm; 39 40STATISTIC(NodesCombined , "Number of dag nodes combined"); 41STATISTIC(PreIndexedNodes , "Number of pre-indexed nodes created"); 42STATISTIC(PostIndexedNodes, "Number of post-indexed nodes created"); 43STATISTIC(OpsNarrowed , "Number of load/op/store narrowed"); 44STATISTIC(LdStFP2Int , "Number of fp load/store pairs transformed to int"); 45 46namespace { 47 static cl::opt<bool> 48 CombinerAA("combiner-alias-analysis", cl::Hidden, 49 cl::desc("Turn on alias analysis during testing")); 50 51 static cl::opt<bool> 52 CombinerGlobalAA("combiner-global-alias-analysis", cl::Hidden, 53 cl::desc("Include global information in alias analysis")); 54 55//------------------------------ DAGCombiner ---------------------------------// 56 57 class DAGCombiner { 58 SelectionDAG &DAG; 59 const TargetLowering &TLI; 60 CombineLevel Level; 61 CodeGenOpt::Level OptLevel; 62 bool LegalOperations; 63 bool LegalTypes; 64 65 // Worklist of all of the nodes that need to be simplified. 66 std::vector<SDNode*> WorkList; 67 68 // AA - Used for DAG load/store alias analysis. 69 AliasAnalysis &AA; 70 71 /// AddUsersToWorkList - When an instruction is simplified, add all users of 72 /// the instruction to the work lists because they might get more simplified 73 /// now. 74 /// 75 void AddUsersToWorkList(SDNode *N) { 76 for (SDNode::use_iterator UI = N->use_begin(), UE = N->use_end(); 77 UI != UE; ++UI) 78 AddToWorkList(*UI); 79 } 80 81 /// visit - call the node-specific routine that knows how to fold each 82 /// particular type of node. 83 SDValue visit(SDNode *N); 84 85 public: 86 /// AddToWorkList - Add to the work list making sure it's instance is at the 87 /// the back (next to be processed.) 88 void AddToWorkList(SDNode *N) { 89 removeFromWorkList(N); 90 WorkList.push_back(N); 91 } 92 93 /// removeFromWorkList - remove all instances of N from the worklist. 94 /// 95 void removeFromWorkList(SDNode *N) { 96 WorkList.erase(std::remove(WorkList.begin(), WorkList.end(), N), 97 WorkList.end()); 98 } 99 100 SDValue CombineTo(SDNode *N, const SDValue *To, unsigned NumTo, 101 bool AddTo = true); 102 103 SDValue CombineTo(SDNode *N, SDValue Res, bool AddTo = true) { 104 return CombineTo(N, &Res, 1, AddTo); 105 } 106 107 SDValue CombineTo(SDNode *N, SDValue Res0, SDValue Res1, 108 bool AddTo = true) { 109 SDValue To[] = { Res0, Res1 }; 110 return CombineTo(N, To, 2, AddTo); 111 } 112 113 void CommitTargetLoweringOpt(const TargetLowering::TargetLoweringOpt &TLO); 114 115 private: 116 117 /// SimplifyDemandedBits - Check the specified integer node value to see if 118 /// it can be simplified or if things it uses can be simplified by bit 119 /// propagation. If so, return true. 120 bool SimplifyDemandedBits(SDValue Op) { 121 unsigned BitWidth = Op.getValueType().getScalarType().getSizeInBits(); 122 APInt Demanded = APInt::getAllOnesValue(BitWidth); 123 return SimplifyDemandedBits(Op, Demanded); 124 } 125 126 bool SimplifyDemandedBits(SDValue Op, const APInt &Demanded); 127 128 bool CombineToPreIndexedLoadStore(SDNode *N); 129 bool CombineToPostIndexedLoadStore(SDNode *N); 130 131 void ReplaceLoadWithPromotedLoad(SDNode *Load, SDNode *ExtLoad); 132 SDValue PromoteOperand(SDValue Op, EVT PVT, bool &Replace); 133 SDValue SExtPromoteOperand(SDValue Op, EVT PVT); 134 SDValue ZExtPromoteOperand(SDValue Op, EVT PVT); 135 SDValue PromoteIntBinOp(SDValue Op); 136 SDValue PromoteIntShiftOp(SDValue Op); 137 SDValue PromoteExtend(SDValue Op); 138 bool PromoteLoad(SDValue Op); 139 140 void ExtendSetCCUses(SmallVector<SDNode*, 4> SetCCs, 141 SDValue Trunc, SDValue ExtLoad, DebugLoc DL, 142 ISD::NodeType ExtType); 143 144 /// combine - call the node-specific routine that knows how to fold each 145 /// particular type of node. If that doesn't do anything, try the 146 /// target-specific DAG combines. 147 SDValue combine(SDNode *N); 148 149 // Visitation implementation - Implement dag node combining for different 150 // node types. The semantics are as follows: 151 // Return Value: 152 // SDValue.getNode() == 0 - No change was made 153 // SDValue.getNode() == N - N was replaced, is dead and has been handled. 154 // otherwise - N should be replaced by the returned Operand. 155 // 156 SDValue visitTokenFactor(SDNode *N); 157 SDValue visitMERGE_VALUES(SDNode *N); 158 SDValue visitADD(SDNode *N); 159 SDValue visitSUB(SDNode *N); 160 SDValue visitADDC(SDNode *N); 161 SDValue visitSUBC(SDNode *N); 162 SDValue visitADDE(SDNode *N); 163 SDValue visitSUBE(SDNode *N); 164 SDValue visitMUL(SDNode *N); 165 SDValue visitSDIV(SDNode *N); 166 SDValue visitUDIV(SDNode *N); 167 SDValue visitSREM(SDNode *N); 168 SDValue visitUREM(SDNode *N); 169 SDValue visitMULHU(SDNode *N); 170 SDValue visitMULHS(SDNode *N); 171 SDValue visitSMUL_LOHI(SDNode *N); 172 SDValue visitUMUL_LOHI(SDNode *N); 173 SDValue visitSMULO(SDNode *N); 174 SDValue visitUMULO(SDNode *N); 175 SDValue visitSDIVREM(SDNode *N); 176 SDValue visitUDIVREM(SDNode *N); 177 SDValue visitAND(SDNode *N); 178 SDValue visitOR(SDNode *N); 179 SDValue visitXOR(SDNode *N); 180 SDValue SimplifyVBinOp(SDNode *N); 181 SDValue visitSHL(SDNode *N); 182 SDValue visitSRA(SDNode *N); 183 SDValue visitSRL(SDNode *N); 184 SDValue visitCTLZ(SDNode *N); 185 SDValue visitCTLZ_ZERO_UNDEF(SDNode *N); 186 SDValue visitCTTZ(SDNode *N); 187 SDValue visitCTTZ_ZERO_UNDEF(SDNode *N); 188 SDValue visitCTPOP(SDNode *N); 189 SDValue visitSELECT(SDNode *N); 190 SDValue visitSELECT_CC(SDNode *N); 191 SDValue visitSETCC(SDNode *N); 192 SDValue visitSIGN_EXTEND(SDNode *N); 193 SDValue visitZERO_EXTEND(SDNode *N); 194 SDValue visitANY_EXTEND(SDNode *N); 195 SDValue visitSIGN_EXTEND_INREG(SDNode *N); 196 SDValue visitTRUNCATE(SDNode *N); 197 SDValue visitBITCAST(SDNode *N); 198 SDValue visitBUILD_PAIR(SDNode *N); 199 SDValue visitFADD(SDNode *N); 200 SDValue visitFSUB(SDNode *N); 201 SDValue visitFMUL(SDNode *N); 202 SDValue visitFDIV(SDNode *N); 203 SDValue visitFREM(SDNode *N); 204 SDValue visitFCOPYSIGN(SDNode *N); 205 SDValue visitSINT_TO_FP(SDNode *N); 206 SDValue visitUINT_TO_FP(SDNode *N); 207 SDValue visitFP_TO_SINT(SDNode *N); 208 SDValue visitFP_TO_UINT(SDNode *N); 209 SDValue visitFP_ROUND(SDNode *N); 210 SDValue visitFP_ROUND_INREG(SDNode *N); 211 SDValue visitFP_EXTEND(SDNode *N); 212 SDValue visitFNEG(SDNode *N); 213 SDValue visitFABS(SDNode *N); 214 SDValue visitBRCOND(SDNode *N); 215 SDValue visitBR_CC(SDNode *N); 216 SDValue visitLOAD(SDNode *N); 217 SDValue visitSTORE(SDNode *N); 218 SDValue visitINSERT_VECTOR_ELT(SDNode *N); 219 SDValue visitEXTRACT_VECTOR_ELT(SDNode *N); 220 SDValue visitBUILD_VECTOR(SDNode *N); 221 SDValue visitCONCAT_VECTORS(SDNode *N); 222 SDValue visitEXTRACT_SUBVECTOR(SDNode *N); 223 SDValue visitVECTOR_SHUFFLE(SDNode *N); 224 SDValue visitMEMBARRIER(SDNode *N); 225 226 SDValue XformToShuffleWithZero(SDNode *N); 227 SDValue ReassociateOps(unsigned Opc, DebugLoc DL, SDValue LHS, SDValue RHS); 228 229 SDValue visitShiftByConstant(SDNode *N, unsigned Amt); 230 231 bool SimplifySelectOps(SDNode *SELECT, SDValue LHS, SDValue RHS); 232 SDValue SimplifyBinOpWithSameOpcodeHands(SDNode *N); 233 SDValue SimplifySelect(DebugLoc DL, SDValue N0, SDValue N1, SDValue N2); 234 SDValue SimplifySelectCC(DebugLoc DL, SDValue N0, SDValue N1, SDValue N2, 235 SDValue N3, ISD::CondCode CC, 236 bool NotExtCompare = false); 237 SDValue SimplifySetCC(EVT VT, SDValue N0, SDValue N1, ISD::CondCode Cond, 238 DebugLoc DL, bool foldBooleans = true); 239 SDValue SimplifyNodeWithTwoResults(SDNode *N, unsigned LoOp, 240 unsigned HiOp); 241 SDValue CombineConsecutiveLoads(SDNode *N, EVT VT); 242 SDValue ConstantFoldBITCASTofBUILD_VECTOR(SDNode *, EVT); 243 SDValue BuildSDIV(SDNode *N); 244 SDValue BuildUDIV(SDNode *N); 245 SDValue MatchBSwapHWordLow(SDNode *N, SDValue N0, SDValue N1, 246 bool DemandHighBits = true); 247 SDValue MatchBSwapHWord(SDNode *N, SDValue N0, SDValue N1); 248 SDNode *MatchRotate(SDValue LHS, SDValue RHS, DebugLoc DL); 249 SDValue ReduceLoadWidth(SDNode *N); 250 SDValue ReduceLoadOpStoreWidth(SDNode *N); 251 SDValue TransformFPLoadStorePair(SDNode *N); 252 253 SDValue GetDemandedBits(SDValue V, const APInt &Mask); 254 255 /// GatherAllAliases - Walk up chain skipping non-aliasing memory nodes, 256 /// looking for aliasing nodes and adding them to the Aliases vector. 257 void GatherAllAliases(SDNode *N, SDValue OriginalChain, 258 SmallVector<SDValue, 8> &Aliases); 259 260 /// isAlias - Return true if there is any possibility that the two addresses 261 /// overlap. 262 bool isAlias(SDValue Ptr1, int64_t Size1, 263 const Value *SrcValue1, int SrcValueOffset1, 264 unsigned SrcValueAlign1, 265 const MDNode *TBAAInfo1, 266 SDValue Ptr2, int64_t Size2, 267 const Value *SrcValue2, int SrcValueOffset2, 268 unsigned SrcValueAlign2, 269 const MDNode *TBAAInfo2) const; 270 271 /// FindAliasInfo - Extracts the relevant alias information from the memory 272 /// node. Returns true if the operand was a load. 273 bool FindAliasInfo(SDNode *N, 274 SDValue &Ptr, int64_t &Size, 275 const Value *&SrcValue, int &SrcValueOffset, 276 unsigned &SrcValueAlignment, 277 const MDNode *&TBAAInfo) const; 278 279 /// FindBetterChain - Walk up chain skipping non-aliasing memory nodes, 280 /// looking for a better chain (aliasing node.) 281 SDValue FindBetterChain(SDNode *N, SDValue Chain); 282 283 public: 284 DAGCombiner(SelectionDAG &D, AliasAnalysis &A, CodeGenOpt::Level OL) 285 : DAG(D), TLI(D.getTargetLoweringInfo()), Level(BeforeLegalizeTypes), 286 OptLevel(OL), LegalOperations(false), LegalTypes(false), AA(A) {} 287 288 /// Run - runs the dag combiner on all nodes in the work list 289 void Run(CombineLevel AtLevel); 290 291 SelectionDAG &getDAG() const { return DAG; } 292 293 /// getShiftAmountTy - Returns a type large enough to hold any valid 294 /// shift amount - before type legalization these can be huge. 295 EVT getShiftAmountTy(EVT LHSTy) { 296 return LegalTypes ? TLI.getShiftAmountTy(LHSTy) : TLI.getPointerTy(); 297 } 298 299 /// isTypeLegal - This method returns true if we are running before type 300 /// legalization or if the specified VT is legal. 301 bool isTypeLegal(const EVT &VT) { 302 if (!LegalTypes) return true; 303 return TLI.isTypeLegal(VT); 304 } 305 }; 306} 307 308 309namespace { 310/// WorkListRemover - This class is a DAGUpdateListener that removes any deleted 311/// nodes from the worklist. 312class WorkListRemover : public SelectionDAG::DAGUpdateListener { 313 DAGCombiner &DC; 314public: 315 explicit WorkListRemover(DAGCombiner &dc) : DC(dc) {} 316 317 virtual void NodeDeleted(SDNode *N, SDNode *E) { 318 DC.removeFromWorkList(N); 319 } 320 321 virtual void NodeUpdated(SDNode *N) { 322 // Ignore updates. 323 } 324}; 325} 326 327//===----------------------------------------------------------------------===// 328// TargetLowering::DAGCombinerInfo implementation 329//===----------------------------------------------------------------------===// 330 331void TargetLowering::DAGCombinerInfo::AddToWorklist(SDNode *N) { 332 ((DAGCombiner*)DC)->AddToWorkList(N); 333} 334 335void TargetLowering::DAGCombinerInfo::RemoveFromWorklist(SDNode *N) { 336 ((DAGCombiner*)DC)->removeFromWorkList(N); 337} 338 339SDValue TargetLowering::DAGCombinerInfo:: 340CombineTo(SDNode *N, const std::vector<SDValue> &To, bool AddTo) { 341 return ((DAGCombiner*)DC)->CombineTo(N, &To[0], To.size(), AddTo); 342} 343 344SDValue TargetLowering::DAGCombinerInfo:: 345CombineTo(SDNode *N, SDValue Res, bool AddTo) { 346 return ((DAGCombiner*)DC)->CombineTo(N, Res, AddTo); 347} 348 349 350SDValue TargetLowering::DAGCombinerInfo:: 351CombineTo(SDNode *N, SDValue Res0, SDValue Res1, bool AddTo) { 352 return ((DAGCombiner*)DC)->CombineTo(N, Res0, Res1, AddTo); 353} 354 355void TargetLowering::DAGCombinerInfo:: 356CommitTargetLoweringOpt(const TargetLowering::TargetLoweringOpt &TLO) { 357 return ((DAGCombiner*)DC)->CommitTargetLoweringOpt(TLO); 358} 359 360//===----------------------------------------------------------------------===// 361// Helper Functions 362//===----------------------------------------------------------------------===// 363 364/// isNegatibleForFree - Return 1 if we can compute the negated form of the 365/// specified expression for the same cost as the expression itself, or 2 if we 366/// can compute the negated form more cheaply than the expression itself. 367static char isNegatibleForFree(SDValue Op, bool LegalOperations, 368 const TargetOptions *Options, 369 unsigned Depth = 0) { 370 // No compile time optimizations on this type. 371 if (Op.getValueType() == MVT::ppcf128) 372 return 0; 373 374 // fneg is removable even if it has multiple uses. 375 if (Op.getOpcode() == ISD::FNEG) return 2; 376 377 // Don't allow anything with multiple uses. 378 if (!Op.hasOneUse()) return 0; 379 380 // Don't recurse exponentially. 381 if (Depth > 6) return 0; 382 383 switch (Op.getOpcode()) { 384 default: return false; 385 case ISD::ConstantFP: 386 // Don't invert constant FP values after legalize. The negated constant 387 // isn't necessarily legal. 388 return LegalOperations ? 0 : 1; 389 case ISD::FADD: 390 // FIXME: determine better conditions for this xform. 391 if (!Options->UnsafeFPMath) return 0; 392 393 // fold (fsub (fadd A, B)) -> (fsub (fneg A), B) 394 if (char V = isNegatibleForFree(Op.getOperand(0), LegalOperations, Options, 395 Depth + 1)) 396 return V; 397 // fold (fneg (fadd A, B)) -> (fsub (fneg B), A) 398 return isNegatibleForFree(Op.getOperand(1), LegalOperations, Options, 399 Depth + 1); 400 case ISD::FSUB: 401 // We can't turn -(A-B) into B-A when we honor signed zeros. 402 if (!Options->UnsafeFPMath) return 0; 403 404 // fold (fneg (fsub A, B)) -> (fsub B, A) 405 return 1; 406 407 case ISD::FMUL: 408 case ISD::FDIV: 409 if (Options->HonorSignDependentRoundingFPMath()) return 0; 410 411 // fold (fneg (fmul X, Y)) -> (fmul (fneg X), Y) or (fmul X, (fneg Y)) 412 if (char V = isNegatibleForFree(Op.getOperand(0), LegalOperations, Options, 413 Depth + 1)) 414 return V; 415 416 return isNegatibleForFree(Op.getOperand(1), LegalOperations, Options, 417 Depth + 1); 418 419 case ISD::FP_EXTEND: 420 case ISD::FP_ROUND: 421 case ISD::FSIN: 422 return isNegatibleForFree(Op.getOperand(0), LegalOperations, Options, 423 Depth + 1); 424 } 425} 426 427/// GetNegatedExpression - If isNegatibleForFree returns true, this function 428/// returns the newly negated expression. 429static SDValue GetNegatedExpression(SDValue Op, SelectionDAG &DAG, 430 bool LegalOperations, unsigned Depth = 0) { 431 // fneg is removable even if it has multiple uses. 432 if (Op.getOpcode() == ISD::FNEG) return Op.getOperand(0); 433 434 // Don't allow anything with multiple uses. 435 assert(Op.hasOneUse() && "Unknown reuse!"); 436 437 assert(Depth <= 6 && "GetNegatedExpression doesn't match isNegatibleForFree"); 438 switch (Op.getOpcode()) { 439 default: llvm_unreachable("Unknown code"); 440 case ISD::ConstantFP: { 441 APFloat V = cast<ConstantFPSDNode>(Op)->getValueAPF(); 442 V.changeSign(); 443 return DAG.getConstantFP(V, Op.getValueType()); 444 } 445 case ISD::FADD: 446 // FIXME: determine better conditions for this xform. 447 assert(DAG.getTarget().Options.UnsafeFPMath); 448 449 // fold (fneg (fadd A, B)) -> (fsub (fneg A), B) 450 if (isNegatibleForFree(Op.getOperand(0), LegalOperations, 451 &DAG.getTarget().Options, Depth+1)) 452 return DAG.getNode(ISD::FSUB, Op.getDebugLoc(), Op.getValueType(), 453 GetNegatedExpression(Op.getOperand(0), DAG, 454 LegalOperations, Depth+1), 455 Op.getOperand(1)); 456 // fold (fneg (fadd A, B)) -> (fsub (fneg B), A) 457 return DAG.getNode(ISD::FSUB, Op.getDebugLoc(), Op.getValueType(), 458 GetNegatedExpression(Op.getOperand(1), DAG, 459 LegalOperations, Depth+1), 460 Op.getOperand(0)); 461 case ISD::FSUB: 462 // We can't turn -(A-B) into B-A when we honor signed zeros. 463 assert(DAG.getTarget().Options.UnsafeFPMath); 464 465 // fold (fneg (fsub 0, B)) -> B 466 if (ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(Op.getOperand(0))) 467 if (N0CFP->getValueAPF().isZero()) 468 return Op.getOperand(1); 469 470 // fold (fneg (fsub A, B)) -> (fsub B, A) 471 return DAG.getNode(ISD::FSUB, Op.getDebugLoc(), Op.getValueType(), 472 Op.getOperand(1), Op.getOperand(0)); 473 474 case ISD::FMUL: 475 case ISD::FDIV: 476 assert(!DAG.getTarget().Options.HonorSignDependentRoundingFPMath()); 477 478 // fold (fneg (fmul X, Y)) -> (fmul (fneg X), Y) 479 if (isNegatibleForFree(Op.getOperand(0), LegalOperations, 480 &DAG.getTarget().Options, Depth+1)) 481 return DAG.getNode(Op.getOpcode(), Op.getDebugLoc(), Op.getValueType(), 482 GetNegatedExpression(Op.getOperand(0), DAG, 483 LegalOperations, Depth+1), 484 Op.getOperand(1)); 485 486 // fold (fneg (fmul X, Y)) -> (fmul X, (fneg Y)) 487 return DAG.getNode(Op.getOpcode(), Op.getDebugLoc(), Op.getValueType(), 488 Op.getOperand(0), 489 GetNegatedExpression(Op.getOperand(1), DAG, 490 LegalOperations, Depth+1)); 491 492 case ISD::FP_EXTEND: 493 case ISD::FSIN: 494 return DAG.getNode(Op.getOpcode(), Op.getDebugLoc(), Op.getValueType(), 495 GetNegatedExpression(Op.getOperand(0), DAG, 496 LegalOperations, Depth+1)); 497 case ISD::FP_ROUND: 498 return DAG.getNode(ISD::FP_ROUND, Op.getDebugLoc(), Op.getValueType(), 499 GetNegatedExpression(Op.getOperand(0), DAG, 500 LegalOperations, Depth+1), 501 Op.getOperand(1)); 502 } 503} 504 505 506// isSetCCEquivalent - Return true if this node is a setcc, or is a select_cc 507// that selects between the values 1 and 0, making it equivalent to a setcc. 508// Also, set the incoming LHS, RHS, and CC references to the appropriate 509// nodes based on the type of node we are checking. This simplifies life a 510// bit for the callers. 511static bool isSetCCEquivalent(SDValue N, SDValue &LHS, SDValue &RHS, 512 SDValue &CC) { 513 if (N.getOpcode() == ISD::SETCC) { 514 LHS = N.getOperand(0); 515 RHS = N.getOperand(1); 516 CC = N.getOperand(2); 517 return true; 518 } 519 if (N.getOpcode() == ISD::SELECT_CC && 520 N.getOperand(2).getOpcode() == ISD::Constant && 521 N.getOperand(3).getOpcode() == ISD::Constant && 522 cast<ConstantSDNode>(N.getOperand(2))->getAPIntValue() == 1 && 523 cast<ConstantSDNode>(N.getOperand(3))->isNullValue()) { 524 LHS = N.getOperand(0); 525 RHS = N.getOperand(1); 526 CC = N.getOperand(4); 527 return true; 528 } 529 return false; 530} 531 532// isOneUseSetCC - Return true if this is a SetCC-equivalent operation with only 533// one use. If this is true, it allows the users to invert the operation for 534// free when it is profitable to do so. 535static bool isOneUseSetCC(SDValue N) { 536 SDValue N0, N1, N2; 537 if (isSetCCEquivalent(N, N0, N1, N2) && N.getNode()->hasOneUse()) 538 return true; 539 return false; 540} 541 542SDValue DAGCombiner::ReassociateOps(unsigned Opc, DebugLoc DL, 543 SDValue N0, SDValue N1) { 544 EVT VT = N0.getValueType(); 545 if (N0.getOpcode() == Opc && isa<ConstantSDNode>(N0.getOperand(1))) { 546 if (isa<ConstantSDNode>(N1)) { 547 // reassoc. (op (op x, c1), c2) -> (op x, (op c1, c2)) 548 SDValue OpNode = 549 DAG.FoldConstantArithmetic(Opc, VT, 550 cast<ConstantSDNode>(N0.getOperand(1)), 551 cast<ConstantSDNode>(N1)); 552 return DAG.getNode(Opc, DL, VT, N0.getOperand(0), OpNode); 553 } 554 if (N0.hasOneUse()) { 555 // reassoc. (op (op x, c1), y) -> (op (op x, y), c1) iff x+c1 has one use 556 SDValue OpNode = DAG.getNode(Opc, N0.getDebugLoc(), VT, 557 N0.getOperand(0), N1); 558 AddToWorkList(OpNode.getNode()); 559 return DAG.getNode(Opc, DL, VT, OpNode, N0.getOperand(1)); 560 } 561 } 562 563 if (N1.getOpcode() == Opc && isa<ConstantSDNode>(N1.getOperand(1))) { 564 if (isa<ConstantSDNode>(N0)) { 565 // reassoc. (op c2, (op x, c1)) -> (op x, (op c1, c2)) 566 SDValue OpNode = 567 DAG.FoldConstantArithmetic(Opc, VT, 568 cast<ConstantSDNode>(N1.getOperand(1)), 569 cast<ConstantSDNode>(N0)); 570 return DAG.getNode(Opc, DL, VT, N1.getOperand(0), OpNode); 571 } 572 if (N1.hasOneUse()) { 573 // reassoc. (op y, (op x, c1)) -> (op (op x, y), c1) iff x+c1 has one use 574 SDValue OpNode = DAG.getNode(Opc, N0.getDebugLoc(), VT, 575 N1.getOperand(0), N0); 576 AddToWorkList(OpNode.getNode()); 577 return DAG.getNode(Opc, DL, VT, OpNode, N1.getOperand(1)); 578 } 579 } 580 581 return SDValue(); 582} 583 584SDValue DAGCombiner::CombineTo(SDNode *N, const SDValue *To, unsigned NumTo, 585 bool AddTo) { 586 assert(N->getNumValues() == NumTo && "Broken CombineTo call!"); 587 ++NodesCombined; 588 DEBUG(dbgs() << "\nReplacing.1 "; 589 N->dump(&DAG); 590 dbgs() << "\nWith: "; 591 To[0].getNode()->dump(&DAG); 592 dbgs() << " and " << NumTo-1 << " other values\n"; 593 for (unsigned i = 0, e = NumTo; i != e; ++i) 594 assert((!To[i].getNode() || 595 N->getValueType(i) == To[i].getValueType()) && 596 "Cannot combine value to value of different type!")); 597 WorkListRemover DeadNodes(*this); 598 DAG.ReplaceAllUsesWith(N, To, &DeadNodes); 599 600 if (AddTo) { 601 // Push the new nodes and any users onto the worklist 602 for (unsigned i = 0, e = NumTo; i != e; ++i) { 603 if (To[i].getNode()) { 604 AddToWorkList(To[i].getNode()); 605 AddUsersToWorkList(To[i].getNode()); 606 } 607 } 608 } 609 610 // Finally, if the node is now dead, remove it from the graph. The node 611 // may not be dead if the replacement process recursively simplified to 612 // something else needing this node. 613 if (N->use_empty()) { 614 // Nodes can be reintroduced into the worklist. Make sure we do not 615 // process a node that has been replaced. 616 removeFromWorkList(N); 617 618 // Finally, since the node is now dead, remove it from the graph. 619 DAG.DeleteNode(N); 620 } 621 return SDValue(N, 0); 622} 623 624void DAGCombiner:: 625CommitTargetLoweringOpt(const TargetLowering::TargetLoweringOpt &TLO) { 626 // Replace all uses. If any nodes become isomorphic to other nodes and 627 // are deleted, make sure to remove them from our worklist. 628 WorkListRemover DeadNodes(*this); 629 DAG.ReplaceAllUsesOfValueWith(TLO.Old, TLO.New, &DeadNodes); 630 631 // Push the new node and any (possibly new) users onto the worklist. 632 AddToWorkList(TLO.New.getNode()); 633 AddUsersToWorkList(TLO.New.getNode()); 634 635 // Finally, if the node is now dead, remove it from the graph. The node 636 // may not be dead if the replacement process recursively simplified to 637 // something else needing this node. 638 if (TLO.Old.getNode()->use_empty()) { 639 removeFromWorkList(TLO.Old.getNode()); 640 641 // If the operands of this node are only used by the node, they will now 642 // be dead. Make sure to visit them first to delete dead nodes early. 643 for (unsigned i = 0, e = TLO.Old.getNode()->getNumOperands(); i != e; ++i) 644 if (TLO.Old.getNode()->getOperand(i).getNode()->hasOneUse()) 645 AddToWorkList(TLO.Old.getNode()->getOperand(i).getNode()); 646 647 DAG.DeleteNode(TLO.Old.getNode()); 648 } 649} 650 651/// SimplifyDemandedBits - Check the specified integer node value to see if 652/// it can be simplified or if things it uses can be simplified by bit 653/// propagation. If so, return true. 654bool DAGCombiner::SimplifyDemandedBits(SDValue Op, const APInt &Demanded) { 655 TargetLowering::TargetLoweringOpt TLO(DAG, LegalTypes, LegalOperations); 656 APInt KnownZero, KnownOne; 657 if (!TLI.SimplifyDemandedBits(Op, Demanded, KnownZero, KnownOne, TLO)) 658 return false; 659 660 // Revisit the node. 661 AddToWorkList(Op.getNode()); 662 663 // Replace the old value with the new one. 664 ++NodesCombined; 665 DEBUG(dbgs() << "\nReplacing.2 "; 666 TLO.Old.getNode()->dump(&DAG); 667 dbgs() << "\nWith: "; 668 TLO.New.getNode()->dump(&DAG); 669 dbgs() << '\n'); 670 671 CommitTargetLoweringOpt(TLO); 672 return true; 673} 674 675void DAGCombiner::ReplaceLoadWithPromotedLoad(SDNode *Load, SDNode *ExtLoad) { 676 DebugLoc dl = Load->getDebugLoc(); 677 EVT VT = Load->getValueType(0); 678 SDValue Trunc = DAG.getNode(ISD::TRUNCATE, dl, VT, SDValue(ExtLoad, 0)); 679 680 DEBUG(dbgs() << "\nReplacing.9 "; 681 Load->dump(&DAG); 682 dbgs() << "\nWith: "; 683 Trunc.getNode()->dump(&DAG); 684 dbgs() << '\n'); 685 WorkListRemover DeadNodes(*this); 686 DAG.ReplaceAllUsesOfValueWith(SDValue(Load, 0), Trunc, &DeadNodes); 687 DAG.ReplaceAllUsesOfValueWith(SDValue(Load, 1), SDValue(ExtLoad, 1), 688 &DeadNodes); 689 removeFromWorkList(Load); 690 DAG.DeleteNode(Load); 691 AddToWorkList(Trunc.getNode()); 692} 693 694SDValue DAGCombiner::PromoteOperand(SDValue Op, EVT PVT, bool &Replace) { 695 Replace = false; 696 DebugLoc dl = Op.getDebugLoc(); 697 if (LoadSDNode *LD = dyn_cast<LoadSDNode>(Op)) { 698 EVT MemVT = LD->getMemoryVT(); 699 ISD::LoadExtType ExtType = ISD::isNON_EXTLoad(LD) 700 ? (TLI.isLoadExtLegal(ISD::ZEXTLOAD, MemVT) ? ISD::ZEXTLOAD 701 : ISD::EXTLOAD) 702 : LD->getExtensionType(); 703 Replace = true; 704 return DAG.getExtLoad(ExtType, dl, PVT, 705 LD->getChain(), LD->getBasePtr(), 706 LD->getPointerInfo(), 707 MemVT, LD->isVolatile(), 708 LD->isNonTemporal(), LD->getAlignment()); 709 } 710 711 unsigned Opc = Op.getOpcode(); 712 switch (Opc) { 713 default: break; 714 case ISD::AssertSext: 715 return DAG.getNode(ISD::AssertSext, dl, PVT, 716 SExtPromoteOperand(Op.getOperand(0), PVT), 717 Op.getOperand(1)); 718 case ISD::AssertZext: 719 return DAG.getNode(ISD::AssertZext, dl, PVT, 720 ZExtPromoteOperand(Op.getOperand(0), PVT), 721 Op.getOperand(1)); 722 case ISD::Constant: { 723 unsigned ExtOpc = 724 Op.getValueType().isByteSized() ? ISD::SIGN_EXTEND : ISD::ZERO_EXTEND; 725 return DAG.getNode(ExtOpc, dl, PVT, Op); 726 } 727 } 728 729 if (!TLI.isOperationLegal(ISD::ANY_EXTEND, PVT)) 730 return SDValue(); 731 return DAG.getNode(ISD::ANY_EXTEND, dl, PVT, Op); 732} 733 734SDValue DAGCombiner::SExtPromoteOperand(SDValue Op, EVT PVT) { 735 if (!TLI.isOperationLegal(ISD::SIGN_EXTEND_INREG, PVT)) 736 return SDValue(); 737 EVT OldVT = Op.getValueType(); 738 DebugLoc dl = Op.getDebugLoc(); 739 bool Replace = false; 740 SDValue NewOp = PromoteOperand(Op, PVT, Replace); 741 if (NewOp.getNode() == 0) 742 return SDValue(); 743 AddToWorkList(NewOp.getNode()); 744 745 if (Replace) 746 ReplaceLoadWithPromotedLoad(Op.getNode(), NewOp.getNode()); 747 return DAG.getNode(ISD::SIGN_EXTEND_INREG, dl, NewOp.getValueType(), NewOp, 748 DAG.getValueType(OldVT)); 749} 750 751SDValue DAGCombiner::ZExtPromoteOperand(SDValue Op, EVT PVT) { 752 EVT OldVT = Op.getValueType(); 753 DebugLoc dl = Op.getDebugLoc(); 754 bool Replace = false; 755 SDValue NewOp = PromoteOperand(Op, PVT, Replace); 756 if (NewOp.getNode() == 0) 757 return SDValue(); 758 AddToWorkList(NewOp.getNode()); 759 760 if (Replace) 761 ReplaceLoadWithPromotedLoad(Op.getNode(), NewOp.getNode()); 762 return DAG.getZeroExtendInReg(NewOp, dl, OldVT); 763} 764 765/// PromoteIntBinOp - Promote the specified integer binary operation if the 766/// target indicates it is beneficial. e.g. On x86, it's usually better to 767/// promote i16 operations to i32 since i16 instructions are longer. 768SDValue DAGCombiner::PromoteIntBinOp(SDValue Op) { 769 if (!LegalOperations) 770 return SDValue(); 771 772 EVT VT = Op.getValueType(); 773 if (VT.isVector() || !VT.isInteger()) 774 return SDValue(); 775 776 // If operation type is 'undesirable', e.g. i16 on x86, consider 777 // promoting it. 778 unsigned Opc = Op.getOpcode(); 779 if (TLI.isTypeDesirableForOp(Opc, VT)) 780 return SDValue(); 781 782 EVT PVT = VT; 783 // Consult target whether it is a good idea to promote this operation and 784 // what's the right type to promote it to. 785 if (TLI.IsDesirableToPromoteOp(Op, PVT)) { 786 assert(PVT != VT && "Don't know what type to promote to!"); 787 788 bool Replace0 = false; 789 SDValue N0 = Op.getOperand(0); 790 SDValue NN0 = PromoteOperand(N0, PVT, Replace0); 791 if (NN0.getNode() == 0) 792 return SDValue(); 793 794 bool Replace1 = false; 795 SDValue N1 = Op.getOperand(1); 796 SDValue NN1; 797 if (N0 == N1) 798 NN1 = NN0; 799 else { 800 NN1 = PromoteOperand(N1, PVT, Replace1); 801 if (NN1.getNode() == 0) 802 return SDValue(); 803 } 804 805 AddToWorkList(NN0.getNode()); 806 if (NN1.getNode()) 807 AddToWorkList(NN1.getNode()); 808 809 if (Replace0) 810 ReplaceLoadWithPromotedLoad(N0.getNode(), NN0.getNode()); 811 if (Replace1) 812 ReplaceLoadWithPromotedLoad(N1.getNode(), NN1.getNode()); 813 814 DEBUG(dbgs() << "\nPromoting "; 815 Op.getNode()->dump(&DAG)); 816 DebugLoc dl = Op.getDebugLoc(); 817 return DAG.getNode(ISD::TRUNCATE, dl, VT, 818 DAG.getNode(Opc, dl, PVT, NN0, NN1)); 819 } 820 return SDValue(); 821} 822 823/// PromoteIntShiftOp - Promote the specified integer shift operation if the 824/// target indicates it is beneficial. e.g. On x86, it's usually better to 825/// promote i16 operations to i32 since i16 instructions are longer. 826SDValue DAGCombiner::PromoteIntShiftOp(SDValue Op) { 827 if (!LegalOperations) 828 return SDValue(); 829 830 EVT VT = Op.getValueType(); 831 if (VT.isVector() || !VT.isInteger()) 832 return SDValue(); 833 834 // If operation type is 'undesirable', e.g. i16 on x86, consider 835 // promoting it. 836 unsigned Opc = Op.getOpcode(); 837 if (TLI.isTypeDesirableForOp(Opc, VT)) 838 return SDValue(); 839 840 EVT PVT = VT; 841 // Consult target whether it is a good idea to promote this operation and 842 // what's the right type to promote it to. 843 if (TLI.IsDesirableToPromoteOp(Op, PVT)) { 844 assert(PVT != VT && "Don't know what type to promote to!"); 845 846 bool Replace = false; 847 SDValue N0 = Op.getOperand(0); 848 if (Opc == ISD::SRA) 849 N0 = SExtPromoteOperand(Op.getOperand(0), PVT); 850 else if (Opc == ISD::SRL) 851 N0 = ZExtPromoteOperand(Op.getOperand(0), PVT); 852 else 853 N0 = PromoteOperand(N0, PVT, Replace); 854 if (N0.getNode() == 0) 855 return SDValue(); 856 857 AddToWorkList(N0.getNode()); 858 if (Replace) 859 ReplaceLoadWithPromotedLoad(Op.getOperand(0).getNode(), N0.getNode()); 860 861 DEBUG(dbgs() << "\nPromoting "; 862 Op.getNode()->dump(&DAG)); 863 DebugLoc dl = Op.getDebugLoc(); 864 return DAG.getNode(ISD::TRUNCATE, dl, VT, 865 DAG.getNode(Opc, dl, PVT, N0, Op.getOperand(1))); 866 } 867 return SDValue(); 868} 869 870SDValue DAGCombiner::PromoteExtend(SDValue Op) { 871 if (!LegalOperations) 872 return SDValue(); 873 874 EVT VT = Op.getValueType(); 875 if (VT.isVector() || !VT.isInteger()) 876 return SDValue(); 877 878 // If operation type is 'undesirable', e.g. i16 on x86, consider 879 // promoting it. 880 unsigned Opc = Op.getOpcode(); 881 if (TLI.isTypeDesirableForOp(Opc, VT)) 882 return SDValue(); 883 884 EVT PVT = VT; 885 // Consult target whether it is a good idea to promote this operation and 886 // what's the right type to promote it to. 887 if (TLI.IsDesirableToPromoteOp(Op, PVT)) { 888 assert(PVT != VT && "Don't know what type to promote to!"); 889 // fold (aext (aext x)) -> (aext x) 890 // fold (aext (zext x)) -> (zext x) 891 // fold (aext (sext x)) -> (sext x) 892 DEBUG(dbgs() << "\nPromoting "; 893 Op.getNode()->dump(&DAG)); 894 return DAG.getNode(Op.getOpcode(), Op.getDebugLoc(), VT, Op.getOperand(0)); 895 } 896 return SDValue(); 897} 898 899bool DAGCombiner::PromoteLoad(SDValue Op) { 900 if (!LegalOperations) 901 return false; 902 903 EVT VT = Op.getValueType(); 904 if (VT.isVector() || !VT.isInteger()) 905 return false; 906 907 // If operation type is 'undesirable', e.g. i16 on x86, consider 908 // promoting it. 909 unsigned Opc = Op.getOpcode(); 910 if (TLI.isTypeDesirableForOp(Opc, VT)) 911 return false; 912 913 EVT PVT = VT; 914 // Consult target whether it is a good idea to promote this operation and 915 // what's the right type to promote it to. 916 if (TLI.IsDesirableToPromoteOp(Op, PVT)) { 917 assert(PVT != VT && "Don't know what type to promote to!"); 918 919 DebugLoc dl = Op.getDebugLoc(); 920 SDNode *N = Op.getNode(); 921 LoadSDNode *LD = cast<LoadSDNode>(N); 922 EVT MemVT = LD->getMemoryVT(); 923 ISD::LoadExtType ExtType = ISD::isNON_EXTLoad(LD) 924 ? (TLI.isLoadExtLegal(ISD::ZEXTLOAD, MemVT) ? ISD::ZEXTLOAD 925 : ISD::EXTLOAD) 926 : LD->getExtensionType(); 927 SDValue NewLD = DAG.getExtLoad(ExtType, dl, PVT, 928 LD->getChain(), LD->getBasePtr(), 929 LD->getPointerInfo(), 930 MemVT, LD->isVolatile(), 931 LD->isNonTemporal(), LD->getAlignment()); 932 SDValue Result = DAG.getNode(ISD::TRUNCATE, dl, VT, NewLD); 933 934 DEBUG(dbgs() << "\nPromoting "; 935 N->dump(&DAG); 936 dbgs() << "\nTo: "; 937 Result.getNode()->dump(&DAG); 938 dbgs() << '\n'); 939 WorkListRemover DeadNodes(*this); 940 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Result, &DeadNodes); 941 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), NewLD.getValue(1), &DeadNodes); 942 removeFromWorkList(N); 943 DAG.DeleteNode(N); 944 AddToWorkList(Result.getNode()); 945 return true; 946 } 947 return false; 948} 949 950 951//===----------------------------------------------------------------------===// 952// Main DAG Combiner implementation 953//===----------------------------------------------------------------------===// 954 955void DAGCombiner::Run(CombineLevel AtLevel) { 956 // set the instance variables, so that the various visit routines may use it. 957 Level = AtLevel; 958 LegalOperations = Level >= AfterLegalizeVectorOps; 959 LegalTypes = Level >= AfterLegalizeTypes; 960 961 // Add all the dag nodes to the worklist. 962 WorkList.reserve(DAG.allnodes_size()); 963 for (SelectionDAG::allnodes_iterator I = DAG.allnodes_begin(), 964 E = DAG.allnodes_end(); I != E; ++I) 965 WorkList.push_back(I); 966 967 // Create a dummy node (which is not added to allnodes), that adds a reference 968 // to the root node, preventing it from being deleted, and tracking any 969 // changes of the root. 970 HandleSDNode Dummy(DAG.getRoot()); 971 972 // The root of the dag may dangle to deleted nodes until the dag combiner is 973 // done. Set it to null to avoid confusion. 974 DAG.setRoot(SDValue()); 975 976 // while the worklist isn't empty, inspect the node on the end of it and 977 // try and combine it. 978 while (!WorkList.empty()) { 979 SDNode *N = WorkList.back(); 980 WorkList.pop_back(); 981 982 // If N has no uses, it is dead. Make sure to revisit all N's operands once 983 // N is deleted from the DAG, since they too may now be dead or may have a 984 // reduced number of uses, allowing other xforms. 985 if (N->use_empty() && N != &Dummy) { 986 for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) 987 AddToWorkList(N->getOperand(i).getNode()); 988 989 DAG.DeleteNode(N); 990 continue; 991 } 992 993 SDValue RV = combine(N); 994 995 if (RV.getNode() == 0) 996 continue; 997 998 ++NodesCombined; 999 1000 // If we get back the same node we passed in, rather than a new node or 1001 // zero, we know that the node must have defined multiple values and 1002 // CombineTo was used. Since CombineTo takes care of the worklist 1003 // mechanics for us, we have no work to do in this case. 1004 if (RV.getNode() == N) 1005 continue; 1006 1007 assert(N->getOpcode() != ISD::DELETED_NODE && 1008 RV.getNode()->getOpcode() != ISD::DELETED_NODE && 1009 "Node was deleted but visit returned new node!"); 1010 1011 DEBUG(dbgs() << "\nReplacing.3 "; 1012 N->dump(&DAG); 1013 dbgs() << "\nWith: "; 1014 RV.getNode()->dump(&DAG); 1015 dbgs() << '\n'); 1016 1017 // Transfer debug value. 1018 DAG.TransferDbgValues(SDValue(N, 0), RV); 1019 WorkListRemover DeadNodes(*this); 1020 if (N->getNumValues() == RV.getNode()->getNumValues()) 1021 DAG.ReplaceAllUsesWith(N, RV.getNode(), &DeadNodes); 1022 else { 1023 assert(N->getValueType(0) == RV.getValueType() && 1024 N->getNumValues() == 1 && "Type mismatch"); 1025 SDValue OpV = RV; 1026 DAG.ReplaceAllUsesWith(N, &OpV, &DeadNodes); 1027 } 1028 1029 // Push the new node and any users onto the worklist 1030 AddToWorkList(RV.getNode()); 1031 AddUsersToWorkList(RV.getNode()); 1032 1033 // Add any uses of the old node to the worklist in case this node is the 1034 // last one that uses them. They may become dead after this node is 1035 // deleted. 1036 for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) 1037 AddToWorkList(N->getOperand(i).getNode()); 1038 1039 // Finally, if the node is now dead, remove it from the graph. The node 1040 // may not be dead if the replacement process recursively simplified to 1041 // something else needing this node. 1042 if (N->use_empty()) { 1043 // Nodes can be reintroduced into the worklist. Make sure we do not 1044 // process a node that has been replaced. 1045 removeFromWorkList(N); 1046 1047 // Finally, since the node is now dead, remove it from the graph. 1048 DAG.DeleteNode(N); 1049 } 1050 } 1051 1052 // If the root changed (e.g. it was a dead load, update the root). 1053 DAG.setRoot(Dummy.getValue()); 1054} 1055 1056SDValue DAGCombiner::visit(SDNode *N) { 1057 switch (N->getOpcode()) { 1058 default: break; 1059 case ISD::TokenFactor: return visitTokenFactor(N); 1060 case ISD::MERGE_VALUES: return visitMERGE_VALUES(N); 1061 case ISD::ADD: return visitADD(N); 1062 case ISD::SUB: return visitSUB(N); 1063 case ISD::ADDC: return visitADDC(N); 1064 case ISD::SUBC: return visitSUBC(N); 1065 case ISD::ADDE: return visitADDE(N); 1066 case ISD::SUBE: return visitSUBE(N); 1067 case ISD::MUL: return visitMUL(N); 1068 case ISD::SDIV: return visitSDIV(N); 1069 case ISD::UDIV: return visitUDIV(N); 1070 case ISD::SREM: return visitSREM(N); 1071 case ISD::UREM: return visitUREM(N); 1072 case ISD::MULHU: return visitMULHU(N); 1073 case ISD::MULHS: return visitMULHS(N); 1074 case ISD::SMUL_LOHI: return visitSMUL_LOHI(N); 1075 case ISD::UMUL_LOHI: return visitUMUL_LOHI(N); 1076 case ISD::SMULO: return visitSMULO(N); 1077 case ISD::UMULO: return visitUMULO(N); 1078 case ISD::SDIVREM: return visitSDIVREM(N); 1079 case ISD::UDIVREM: return visitUDIVREM(N); 1080 case ISD::AND: return visitAND(N); 1081 case ISD::OR: return visitOR(N); 1082 case ISD::XOR: return visitXOR(N); 1083 case ISD::SHL: return visitSHL(N); 1084 case ISD::SRA: return visitSRA(N); 1085 case ISD::SRL: return visitSRL(N); 1086 case ISD::CTLZ: return visitCTLZ(N); 1087 case ISD::CTLZ_ZERO_UNDEF: return visitCTLZ_ZERO_UNDEF(N); 1088 case ISD::CTTZ: return visitCTTZ(N); 1089 case ISD::CTTZ_ZERO_UNDEF: return visitCTTZ_ZERO_UNDEF(N); 1090 case ISD::CTPOP: return visitCTPOP(N); 1091 case ISD::SELECT: return visitSELECT(N); 1092 case ISD::SELECT_CC: return visitSELECT_CC(N); 1093 case ISD::SETCC: return visitSETCC(N); 1094 case ISD::SIGN_EXTEND: return visitSIGN_EXTEND(N); 1095 case ISD::ZERO_EXTEND: return visitZERO_EXTEND(N); 1096 case ISD::ANY_EXTEND: return visitANY_EXTEND(N); 1097 case ISD::SIGN_EXTEND_INREG: return visitSIGN_EXTEND_INREG(N); 1098 case ISD::TRUNCATE: return visitTRUNCATE(N); 1099 case ISD::BITCAST: return visitBITCAST(N); 1100 case ISD::BUILD_PAIR: return visitBUILD_PAIR(N); 1101 case ISD::FADD: return visitFADD(N); 1102 case ISD::FSUB: return visitFSUB(N); 1103 case ISD::FMUL: return visitFMUL(N); 1104 case ISD::FDIV: return visitFDIV(N); 1105 case ISD::FREM: return visitFREM(N); 1106 case ISD::FCOPYSIGN: return visitFCOPYSIGN(N); 1107 case ISD::SINT_TO_FP: return visitSINT_TO_FP(N); 1108 case ISD::UINT_TO_FP: return visitUINT_TO_FP(N); 1109 case ISD::FP_TO_SINT: return visitFP_TO_SINT(N); 1110 case ISD::FP_TO_UINT: return visitFP_TO_UINT(N); 1111 case ISD::FP_ROUND: return visitFP_ROUND(N); 1112 case ISD::FP_ROUND_INREG: return visitFP_ROUND_INREG(N); 1113 case ISD::FP_EXTEND: return visitFP_EXTEND(N); 1114 case ISD::FNEG: return visitFNEG(N); 1115 case ISD::FABS: return visitFABS(N); 1116 case ISD::BRCOND: return visitBRCOND(N); 1117 case ISD::BR_CC: return visitBR_CC(N); 1118 case ISD::LOAD: return visitLOAD(N); 1119 case ISD::STORE: return visitSTORE(N); 1120 case ISD::INSERT_VECTOR_ELT: return visitINSERT_VECTOR_ELT(N); 1121 case ISD::EXTRACT_VECTOR_ELT: return visitEXTRACT_VECTOR_ELT(N); 1122 case ISD::BUILD_VECTOR: return visitBUILD_VECTOR(N); 1123 case ISD::CONCAT_VECTORS: return visitCONCAT_VECTORS(N); 1124 case ISD::EXTRACT_SUBVECTOR: return visitEXTRACT_SUBVECTOR(N); 1125 case ISD::VECTOR_SHUFFLE: return visitVECTOR_SHUFFLE(N); 1126 case ISD::MEMBARRIER: return visitMEMBARRIER(N); 1127 } 1128 return SDValue(); 1129} 1130 1131SDValue DAGCombiner::combine(SDNode *N) { 1132 SDValue RV = visit(N); 1133 1134 // If nothing happened, try a target-specific DAG combine. 1135 if (RV.getNode() == 0) { 1136 assert(N->getOpcode() != ISD::DELETED_NODE && 1137 "Node was deleted but visit returned NULL!"); 1138 1139 if (N->getOpcode() >= ISD::BUILTIN_OP_END || 1140 TLI.hasTargetDAGCombine((ISD::NodeType)N->getOpcode())) { 1141 1142 // Expose the DAG combiner to the target combiner impls. 1143 TargetLowering::DAGCombinerInfo 1144 DagCombineInfo(DAG, !LegalTypes, !LegalOperations, false, this); 1145 1146 RV = TLI.PerformDAGCombine(N, DagCombineInfo); 1147 } 1148 } 1149 1150 // If nothing happened still, try promoting the operation. 1151 if (RV.getNode() == 0) { 1152 switch (N->getOpcode()) { 1153 default: break; 1154 case ISD::ADD: 1155 case ISD::SUB: 1156 case ISD::MUL: 1157 case ISD::AND: 1158 case ISD::OR: 1159 case ISD::XOR: 1160 RV = PromoteIntBinOp(SDValue(N, 0)); 1161 break; 1162 case ISD::SHL: 1163 case ISD::SRA: 1164 case ISD::SRL: 1165 RV = PromoteIntShiftOp(SDValue(N, 0)); 1166 break; 1167 case ISD::SIGN_EXTEND: 1168 case ISD::ZERO_EXTEND: 1169 case ISD::ANY_EXTEND: 1170 RV = PromoteExtend(SDValue(N, 0)); 1171 break; 1172 case ISD::LOAD: 1173 if (PromoteLoad(SDValue(N, 0))) 1174 RV = SDValue(N, 0); 1175 break; 1176 } 1177 } 1178 1179 // If N is a commutative binary node, try commuting it to enable more 1180 // sdisel CSE. 1181 if (RV.getNode() == 0 && 1182 SelectionDAG::isCommutativeBinOp(N->getOpcode()) && 1183 N->getNumValues() == 1) { 1184 SDValue N0 = N->getOperand(0); 1185 SDValue N1 = N->getOperand(1); 1186 1187 // Constant operands are canonicalized to RHS. 1188 if (isa<ConstantSDNode>(N0) || !isa<ConstantSDNode>(N1)) { 1189 SDValue Ops[] = { N1, N0 }; 1190 SDNode *CSENode = DAG.getNodeIfExists(N->getOpcode(), N->getVTList(), 1191 Ops, 2); 1192 if (CSENode) 1193 return SDValue(CSENode, 0); 1194 } 1195 } 1196 1197 return RV; 1198} 1199 1200/// getInputChainForNode - Given a node, return its input chain if it has one, 1201/// otherwise return a null sd operand. 1202static SDValue getInputChainForNode(SDNode *N) { 1203 if (unsigned NumOps = N->getNumOperands()) { 1204 if (N->getOperand(0).getValueType() == MVT::Other) 1205 return N->getOperand(0); 1206 else if (N->getOperand(NumOps-1).getValueType() == MVT::Other) 1207 return N->getOperand(NumOps-1); 1208 for (unsigned i = 1; i < NumOps-1; ++i) 1209 if (N->getOperand(i).getValueType() == MVT::Other) 1210 return N->getOperand(i); 1211 } 1212 return SDValue(); 1213} 1214 1215SDValue DAGCombiner::visitTokenFactor(SDNode *N) { 1216 // If N has two operands, where one has an input chain equal to the other, 1217 // the 'other' chain is redundant. 1218 if (N->getNumOperands() == 2) { 1219 if (getInputChainForNode(N->getOperand(0).getNode()) == N->getOperand(1)) 1220 return N->getOperand(0); 1221 if (getInputChainForNode(N->getOperand(1).getNode()) == N->getOperand(0)) 1222 return N->getOperand(1); 1223 } 1224 1225 SmallVector<SDNode *, 8> TFs; // List of token factors to visit. 1226 SmallVector<SDValue, 8> Ops; // Ops for replacing token factor. 1227 SmallPtrSet<SDNode*, 16> SeenOps; 1228 bool Changed = false; // If we should replace this token factor. 1229 1230 // Start out with this token factor. 1231 TFs.push_back(N); 1232 1233 // Iterate through token factors. The TFs grows when new token factors are 1234 // encountered. 1235 for (unsigned i = 0; i < TFs.size(); ++i) { 1236 SDNode *TF = TFs[i]; 1237 1238 // Check each of the operands. 1239 for (unsigned i = 0, ie = TF->getNumOperands(); i != ie; ++i) { 1240 SDValue Op = TF->getOperand(i); 1241 1242 switch (Op.getOpcode()) { 1243 case ISD::EntryToken: 1244 // Entry tokens don't need to be added to the list. They are 1245 // rededundant. 1246 Changed = true; 1247 break; 1248 1249 case ISD::TokenFactor: 1250 if (Op.hasOneUse() && 1251 std::find(TFs.begin(), TFs.end(), Op.getNode()) == TFs.end()) { 1252 // Queue up for processing. 1253 TFs.push_back(Op.getNode()); 1254 // Clean up in case the token factor is removed. 1255 AddToWorkList(Op.getNode()); 1256 Changed = true; 1257 break; 1258 } 1259 // Fall thru 1260 1261 default: 1262 // Only add if it isn't already in the list. 1263 if (SeenOps.insert(Op.getNode())) 1264 Ops.push_back(Op); 1265 else 1266 Changed = true; 1267 break; 1268 } 1269 } 1270 } 1271 1272 SDValue Result; 1273 1274 // If we've change things around then replace token factor. 1275 if (Changed) { 1276 if (Ops.empty()) { 1277 // The entry token is the only possible outcome. 1278 Result = DAG.getEntryNode(); 1279 } else { 1280 // New and improved token factor. 1281 Result = DAG.getNode(ISD::TokenFactor, N->getDebugLoc(), 1282 MVT::Other, &Ops[0], Ops.size()); 1283 } 1284 1285 // Don't add users to work list. 1286 return CombineTo(N, Result, false); 1287 } 1288 1289 return Result; 1290} 1291 1292/// MERGE_VALUES can always be eliminated. 1293SDValue DAGCombiner::visitMERGE_VALUES(SDNode *N) { 1294 WorkListRemover DeadNodes(*this); 1295 // Replacing results may cause a different MERGE_VALUES to suddenly 1296 // be CSE'd with N, and carry its uses with it. Iterate until no 1297 // uses remain, to ensure that the node can be safely deleted. 1298 do { 1299 for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) 1300 DAG.ReplaceAllUsesOfValueWith(SDValue(N, i), N->getOperand(i), 1301 &DeadNodes); 1302 } while (!N->use_empty()); 1303 removeFromWorkList(N); 1304 DAG.DeleteNode(N); 1305 return SDValue(N, 0); // Return N so it doesn't get rechecked! 1306} 1307 1308static 1309SDValue combineShlAddConstant(DebugLoc DL, SDValue N0, SDValue N1, 1310 SelectionDAG &DAG) { 1311 EVT VT = N0.getValueType(); 1312 SDValue N00 = N0.getOperand(0); 1313 SDValue N01 = N0.getOperand(1); 1314 ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N01); 1315 1316 if (N01C && N00.getOpcode() == ISD::ADD && N00.getNode()->hasOneUse() && 1317 isa<ConstantSDNode>(N00.getOperand(1))) { 1318 // fold (add (shl (add x, c1), c2), ) -> (add (add (shl x, c2), c1<<c2), ) 1319 N0 = DAG.getNode(ISD::ADD, N0.getDebugLoc(), VT, 1320 DAG.getNode(ISD::SHL, N00.getDebugLoc(), VT, 1321 N00.getOperand(0), N01), 1322 DAG.getNode(ISD::SHL, N01.getDebugLoc(), VT, 1323 N00.getOperand(1), N01)); 1324 return DAG.getNode(ISD::ADD, DL, VT, N0, N1); 1325 } 1326 1327 return SDValue(); 1328} 1329 1330SDValue DAGCombiner::visitADD(SDNode *N) { 1331 SDValue N0 = N->getOperand(0); 1332 SDValue N1 = N->getOperand(1); 1333 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 1334 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1335 EVT VT = N0.getValueType(); 1336 1337 // fold vector ops 1338 if (VT.isVector()) { 1339 SDValue FoldedVOp = SimplifyVBinOp(N); 1340 if (FoldedVOp.getNode()) return FoldedVOp; 1341 } 1342 1343 // fold (add x, undef) -> undef 1344 if (N0.getOpcode() == ISD::UNDEF) 1345 return N0; 1346 if (N1.getOpcode() == ISD::UNDEF) 1347 return N1; 1348 // fold (add c1, c2) -> c1+c2 1349 if (N0C && N1C) 1350 return DAG.FoldConstantArithmetic(ISD::ADD, VT, N0C, N1C); 1351 // canonicalize constant to RHS 1352 if (N0C && !N1C) 1353 return DAG.getNode(ISD::ADD, N->getDebugLoc(), VT, N1, N0); 1354 // fold (add x, 0) -> x 1355 if (N1C && N1C->isNullValue()) 1356 return N0; 1357 // fold (add Sym, c) -> Sym+c 1358 if (GlobalAddressSDNode *GA = dyn_cast<GlobalAddressSDNode>(N0)) 1359 if (!LegalOperations && TLI.isOffsetFoldingLegal(GA) && N1C && 1360 GA->getOpcode() == ISD::GlobalAddress) 1361 return DAG.getGlobalAddress(GA->getGlobal(), N1C->getDebugLoc(), VT, 1362 GA->getOffset() + 1363 (uint64_t)N1C->getSExtValue()); 1364 // fold ((c1-A)+c2) -> (c1+c2)-A 1365 if (N1C && N0.getOpcode() == ISD::SUB) 1366 if (ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.getOperand(0))) 1367 return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, 1368 DAG.getConstant(N1C->getAPIntValue()+ 1369 N0C->getAPIntValue(), VT), 1370 N0.getOperand(1)); 1371 // reassociate add 1372 SDValue RADD = ReassociateOps(ISD::ADD, N->getDebugLoc(), N0, N1); 1373 if (RADD.getNode() != 0) 1374 return RADD; 1375 // fold ((0-A) + B) -> B-A 1376 if (N0.getOpcode() == ISD::SUB && isa<ConstantSDNode>(N0.getOperand(0)) && 1377 cast<ConstantSDNode>(N0.getOperand(0))->isNullValue()) 1378 return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N1, N0.getOperand(1)); 1379 // fold (A + (0-B)) -> A-B 1380 if (N1.getOpcode() == ISD::SUB && isa<ConstantSDNode>(N1.getOperand(0)) && 1381 cast<ConstantSDNode>(N1.getOperand(0))->isNullValue()) 1382 return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N0, N1.getOperand(1)); 1383 // fold (A+(B-A)) -> B 1384 if (N1.getOpcode() == ISD::SUB && N0 == N1.getOperand(1)) 1385 return N1.getOperand(0); 1386 // fold ((B-A)+A) -> B 1387 if (N0.getOpcode() == ISD::SUB && N1 == N0.getOperand(1)) 1388 return N0.getOperand(0); 1389 // fold (A+(B-(A+C))) to (B-C) 1390 if (N1.getOpcode() == ISD::SUB && N1.getOperand(1).getOpcode() == ISD::ADD && 1391 N0 == N1.getOperand(1).getOperand(0)) 1392 return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N1.getOperand(0), 1393 N1.getOperand(1).getOperand(1)); 1394 // fold (A+(B-(C+A))) to (B-C) 1395 if (N1.getOpcode() == ISD::SUB && N1.getOperand(1).getOpcode() == ISD::ADD && 1396 N0 == N1.getOperand(1).getOperand(1)) 1397 return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N1.getOperand(0), 1398 N1.getOperand(1).getOperand(0)); 1399 // fold (A+((B-A)+or-C)) to (B+or-C) 1400 if ((N1.getOpcode() == ISD::SUB || N1.getOpcode() == ISD::ADD) && 1401 N1.getOperand(0).getOpcode() == ISD::SUB && 1402 N0 == N1.getOperand(0).getOperand(1)) 1403 return DAG.getNode(N1.getOpcode(), N->getDebugLoc(), VT, 1404 N1.getOperand(0).getOperand(0), N1.getOperand(1)); 1405 1406 // fold (A-B)+(C-D) to (A+C)-(B+D) when A or C is constant 1407 if (N0.getOpcode() == ISD::SUB && N1.getOpcode() == ISD::SUB) { 1408 SDValue N00 = N0.getOperand(0); 1409 SDValue N01 = N0.getOperand(1); 1410 SDValue N10 = N1.getOperand(0); 1411 SDValue N11 = N1.getOperand(1); 1412 1413 if (isa<ConstantSDNode>(N00) || isa<ConstantSDNode>(N10)) 1414 return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, 1415 DAG.getNode(ISD::ADD, N0.getDebugLoc(), VT, N00, N10), 1416 DAG.getNode(ISD::ADD, N1.getDebugLoc(), VT, N01, N11)); 1417 } 1418 1419 if (!VT.isVector() && SimplifyDemandedBits(SDValue(N, 0))) 1420 return SDValue(N, 0); 1421 1422 // fold (a+b) -> (a|b) iff a and b share no bits. 1423 if (VT.isInteger() && !VT.isVector()) { 1424 APInt LHSZero, LHSOne; 1425 APInt RHSZero, RHSOne; 1426 APInt Mask = APInt::getAllOnesValue(VT.getScalarType().getSizeInBits()); 1427 DAG.ComputeMaskedBits(N0, Mask, LHSZero, LHSOne); 1428 1429 if (LHSZero.getBoolValue()) { 1430 DAG.ComputeMaskedBits(N1, Mask, RHSZero, RHSOne); 1431 1432 // If all possibly-set bits on the LHS are clear on the RHS, return an OR. 1433 // If all possibly-set bits on the RHS are clear on the LHS, return an OR. 1434 if ((RHSZero & (~LHSZero & Mask)) == (~LHSZero & Mask) || 1435 (LHSZero & (~RHSZero & Mask)) == (~RHSZero & Mask)) 1436 return DAG.getNode(ISD::OR, N->getDebugLoc(), VT, N0, N1); 1437 } 1438 } 1439 1440 // fold (add (shl (add x, c1), c2), ) -> (add (add (shl x, c2), c1<<c2), ) 1441 if (N0.getOpcode() == ISD::SHL && N0.getNode()->hasOneUse()) { 1442 SDValue Result = combineShlAddConstant(N->getDebugLoc(), N0, N1, DAG); 1443 if (Result.getNode()) return Result; 1444 } 1445 if (N1.getOpcode() == ISD::SHL && N1.getNode()->hasOneUse()) { 1446 SDValue Result = combineShlAddConstant(N->getDebugLoc(), N1, N0, DAG); 1447 if (Result.getNode()) return Result; 1448 } 1449 1450 // fold (add x, shl(0 - y, n)) -> sub(x, shl(y, n)) 1451 if (N1.getOpcode() == ISD::SHL && 1452 N1.getOperand(0).getOpcode() == ISD::SUB) 1453 if (ConstantSDNode *C = 1454 dyn_cast<ConstantSDNode>(N1.getOperand(0).getOperand(0))) 1455 if (C->getAPIntValue() == 0) 1456 return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N0, 1457 DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, 1458 N1.getOperand(0).getOperand(1), 1459 N1.getOperand(1))); 1460 if (N0.getOpcode() == ISD::SHL && 1461 N0.getOperand(0).getOpcode() == ISD::SUB) 1462 if (ConstantSDNode *C = 1463 dyn_cast<ConstantSDNode>(N0.getOperand(0).getOperand(0))) 1464 if (C->getAPIntValue() == 0) 1465 return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N1, 1466 DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, 1467 N0.getOperand(0).getOperand(1), 1468 N0.getOperand(1))); 1469 1470 if (N1.getOpcode() == ISD::AND) { 1471 SDValue AndOp0 = N1.getOperand(0); 1472 ConstantSDNode *AndOp1 = dyn_cast<ConstantSDNode>(N1->getOperand(1)); 1473 unsigned NumSignBits = DAG.ComputeNumSignBits(AndOp0); 1474 unsigned DestBits = VT.getScalarType().getSizeInBits(); 1475 1476 // (add z, (and (sbbl x, x), 1)) -> (sub z, (sbbl x, x)) 1477 // and similar xforms where the inner op is either ~0 or 0. 1478 if (NumSignBits == DestBits && AndOp1 && AndOp1->isOne()) { 1479 DebugLoc DL = N->getDebugLoc(); 1480 return DAG.getNode(ISD::SUB, DL, VT, N->getOperand(0), AndOp0); 1481 } 1482 } 1483 1484 // add (sext i1), X -> sub X, (zext i1) 1485 if (N0.getOpcode() == ISD::SIGN_EXTEND && 1486 N0.getOperand(0).getValueType() == MVT::i1 && 1487 !TLI.isOperationLegal(ISD::SIGN_EXTEND, MVT::i1)) { 1488 DebugLoc DL = N->getDebugLoc(); 1489 SDValue ZExt = DAG.getNode(ISD::ZERO_EXTEND, DL, VT, N0.getOperand(0)); 1490 return DAG.getNode(ISD::SUB, DL, VT, N1, ZExt); 1491 } 1492 1493 return SDValue(); 1494} 1495 1496SDValue DAGCombiner::visitADDC(SDNode *N) { 1497 SDValue N0 = N->getOperand(0); 1498 SDValue N1 = N->getOperand(1); 1499 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 1500 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1501 EVT VT = N0.getValueType(); 1502 1503 // If the flag result is dead, turn this into an ADD. 1504 if (!N->hasAnyUseOfValue(1)) 1505 return CombineTo(N, DAG.getNode(ISD::ADD, N->getDebugLoc(), VT, N0, N1), 1506 DAG.getNode(ISD::CARRY_FALSE, 1507 N->getDebugLoc(), MVT::Glue)); 1508 1509 // canonicalize constant to RHS. 1510 if (N0C && !N1C) 1511 return DAG.getNode(ISD::ADDC, N->getDebugLoc(), N->getVTList(), N1, N0); 1512 1513 // fold (addc x, 0) -> x + no carry out 1514 if (N1C && N1C->isNullValue()) 1515 return CombineTo(N, N0, DAG.getNode(ISD::CARRY_FALSE, 1516 N->getDebugLoc(), MVT::Glue)); 1517 1518 // fold (addc a, b) -> (or a, b), CARRY_FALSE iff a and b share no bits. 1519 APInt LHSZero, LHSOne; 1520 APInt RHSZero, RHSOne; 1521 APInt Mask = APInt::getAllOnesValue(VT.getScalarType().getSizeInBits()); 1522 DAG.ComputeMaskedBits(N0, Mask, LHSZero, LHSOne); 1523 1524 if (LHSZero.getBoolValue()) { 1525 DAG.ComputeMaskedBits(N1, Mask, RHSZero, RHSOne); 1526 1527 // If all possibly-set bits on the LHS are clear on the RHS, return an OR. 1528 // If all possibly-set bits on the RHS are clear on the LHS, return an OR. 1529 if ((RHSZero & (~LHSZero & Mask)) == (~LHSZero & Mask) || 1530 (LHSZero & (~RHSZero & Mask)) == (~RHSZero & Mask)) 1531 return CombineTo(N, DAG.getNode(ISD::OR, N->getDebugLoc(), VT, N0, N1), 1532 DAG.getNode(ISD::CARRY_FALSE, 1533 N->getDebugLoc(), MVT::Glue)); 1534 } 1535 1536 return SDValue(); 1537} 1538 1539SDValue DAGCombiner::visitADDE(SDNode *N) { 1540 SDValue N0 = N->getOperand(0); 1541 SDValue N1 = N->getOperand(1); 1542 SDValue CarryIn = N->getOperand(2); 1543 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 1544 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1545 1546 // canonicalize constant to RHS 1547 if (N0C && !N1C) 1548 return DAG.getNode(ISD::ADDE, N->getDebugLoc(), N->getVTList(), 1549 N1, N0, CarryIn); 1550 1551 // fold (adde x, y, false) -> (addc x, y) 1552 if (CarryIn.getOpcode() == ISD::CARRY_FALSE) 1553 return DAG.getNode(ISD::ADDC, N->getDebugLoc(), N->getVTList(), N0, N1); 1554 1555 return SDValue(); 1556} 1557 1558// Since it may not be valid to emit a fold to zero for vector initializers 1559// check if we can before folding. 1560static SDValue tryFoldToZero(DebugLoc DL, const TargetLowering &TLI, EVT VT, 1561 SelectionDAG &DAG, bool LegalOperations) { 1562 if (!VT.isVector()) { 1563 return DAG.getConstant(0, VT); 1564 } 1565 if (!LegalOperations || TLI.isOperationLegal(ISD::BUILD_VECTOR, VT)) { 1566 // Produce a vector of zeros. 1567 SDValue El = DAG.getConstant(0, VT.getVectorElementType()); 1568 std::vector<SDValue> Ops(VT.getVectorNumElements(), El); 1569 return DAG.getNode(ISD::BUILD_VECTOR, DL, VT, 1570 &Ops[0], Ops.size()); 1571 } 1572 return SDValue(); 1573} 1574 1575SDValue DAGCombiner::visitSUB(SDNode *N) { 1576 SDValue N0 = N->getOperand(0); 1577 SDValue N1 = N->getOperand(1); 1578 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.getNode()); 1579 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.getNode()); 1580 ConstantSDNode *N1C1 = N1.getOpcode() != ISD::ADD ? 0 : 1581 dyn_cast<ConstantSDNode>(N1.getOperand(1).getNode()); 1582 EVT VT = N0.getValueType(); 1583 1584 // fold vector ops 1585 if (VT.isVector()) { 1586 SDValue FoldedVOp = SimplifyVBinOp(N); 1587 if (FoldedVOp.getNode()) return FoldedVOp; 1588 } 1589 1590 // fold (sub x, x) -> 0 1591 // FIXME: Refactor this and xor and other similar operations together. 1592 if (N0 == N1) 1593 return tryFoldToZero(N->getDebugLoc(), TLI, VT, DAG, LegalOperations); 1594 // fold (sub c1, c2) -> c1-c2 1595 if (N0C && N1C) 1596 return DAG.FoldConstantArithmetic(ISD::SUB, VT, N0C, N1C); 1597 // fold (sub x, c) -> (add x, -c) 1598 if (N1C) 1599 return DAG.getNode(ISD::ADD, N->getDebugLoc(), VT, N0, 1600 DAG.getConstant(-N1C->getAPIntValue(), VT)); 1601 // Canonicalize (sub -1, x) -> ~x, i.e. (xor x, -1) 1602 if (N0C && N0C->isAllOnesValue()) 1603 return DAG.getNode(ISD::XOR, N->getDebugLoc(), VT, N1, N0); 1604 // fold A-(A-B) -> B 1605 if (N1.getOpcode() == ISD::SUB && N0 == N1.getOperand(0)) 1606 return N1.getOperand(1); 1607 // fold (A+B)-A -> B 1608 if (N0.getOpcode() == ISD::ADD && N0.getOperand(0) == N1) 1609 return N0.getOperand(1); 1610 // fold (A+B)-B -> A 1611 if (N0.getOpcode() == ISD::ADD && N0.getOperand(1) == N1) 1612 return N0.getOperand(0); 1613 // fold C2-(A+C1) -> (C2-C1)-A 1614 if (N1.getOpcode() == ISD::ADD && N0C && N1C1) { 1615 SDValue NewC = DAG.getConstant((N0C->getAPIntValue() - N1C1->getAPIntValue()), VT); 1616 return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, NewC, 1617 N1.getOperand(0)); 1618 } 1619 // fold ((A+(B+or-C))-B) -> A+or-C 1620 if (N0.getOpcode() == ISD::ADD && 1621 (N0.getOperand(1).getOpcode() == ISD::SUB || 1622 N0.getOperand(1).getOpcode() == ISD::ADD) && 1623 N0.getOperand(1).getOperand(0) == N1) 1624 return DAG.getNode(N0.getOperand(1).getOpcode(), N->getDebugLoc(), VT, 1625 N0.getOperand(0), N0.getOperand(1).getOperand(1)); 1626 // fold ((A+(C+B))-B) -> A+C 1627 if (N0.getOpcode() == ISD::ADD && 1628 N0.getOperand(1).getOpcode() == ISD::ADD && 1629 N0.getOperand(1).getOperand(1) == N1) 1630 return DAG.getNode(ISD::ADD, N->getDebugLoc(), VT, 1631 N0.getOperand(0), N0.getOperand(1).getOperand(0)); 1632 // fold ((A-(B-C))-C) -> A-B 1633 if (N0.getOpcode() == ISD::SUB && 1634 N0.getOperand(1).getOpcode() == ISD::SUB && 1635 N0.getOperand(1).getOperand(1) == N1) 1636 return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, 1637 N0.getOperand(0), N0.getOperand(1).getOperand(0)); 1638 1639 // If either operand of a sub is undef, the result is undef 1640 if (N0.getOpcode() == ISD::UNDEF) 1641 return N0; 1642 if (N1.getOpcode() == ISD::UNDEF) 1643 return N1; 1644 1645 // If the relocation model supports it, consider symbol offsets. 1646 if (GlobalAddressSDNode *GA = dyn_cast<GlobalAddressSDNode>(N0)) 1647 if (!LegalOperations && TLI.isOffsetFoldingLegal(GA)) { 1648 // fold (sub Sym, c) -> Sym-c 1649 if (N1C && GA->getOpcode() == ISD::GlobalAddress) 1650 return DAG.getGlobalAddress(GA->getGlobal(), N1C->getDebugLoc(), VT, 1651 GA->getOffset() - 1652 (uint64_t)N1C->getSExtValue()); 1653 // fold (sub Sym+c1, Sym+c2) -> c1-c2 1654 if (GlobalAddressSDNode *GB = dyn_cast<GlobalAddressSDNode>(N1)) 1655 if (GA->getGlobal() == GB->getGlobal()) 1656 return DAG.getConstant((uint64_t)GA->getOffset() - GB->getOffset(), 1657 VT); 1658 } 1659 1660 return SDValue(); 1661} 1662 1663SDValue DAGCombiner::visitSUBC(SDNode *N) { 1664 SDValue N0 = N->getOperand(0); 1665 SDValue N1 = N->getOperand(1); 1666 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 1667 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1668 EVT VT = N0.getValueType(); 1669 1670 // If the flag result is dead, turn this into an SUB. 1671 if (!N->hasAnyUseOfValue(1)) 1672 return CombineTo(N, DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N0, N1), 1673 DAG.getNode(ISD::CARRY_FALSE, N->getDebugLoc(), 1674 MVT::Glue)); 1675 1676 // fold (subc x, x) -> 0 + no borrow 1677 if (N0 == N1) 1678 return CombineTo(N, DAG.getConstant(0, VT), 1679 DAG.getNode(ISD::CARRY_FALSE, N->getDebugLoc(), 1680 MVT::Glue)); 1681 1682 // fold (subc x, 0) -> x + no borrow 1683 if (N1C && N1C->isNullValue()) 1684 return CombineTo(N, N0, DAG.getNode(ISD::CARRY_FALSE, N->getDebugLoc(), 1685 MVT::Glue)); 1686 1687 // Canonicalize (sub -1, x) -> ~x, i.e. (xor x, -1) + no borrow 1688 if (N0C && N0C->isAllOnesValue()) 1689 return CombineTo(N, DAG.getNode(ISD::XOR, N->getDebugLoc(), VT, N1, N0), 1690 DAG.getNode(ISD::CARRY_FALSE, N->getDebugLoc(), 1691 MVT::Glue)); 1692 1693 return SDValue(); 1694} 1695 1696SDValue DAGCombiner::visitSUBE(SDNode *N) { 1697 SDValue N0 = N->getOperand(0); 1698 SDValue N1 = N->getOperand(1); 1699 SDValue CarryIn = N->getOperand(2); 1700 1701 // fold (sube x, y, false) -> (subc x, y) 1702 if (CarryIn.getOpcode() == ISD::CARRY_FALSE) 1703 return DAG.getNode(ISD::SUBC, N->getDebugLoc(), N->getVTList(), N0, N1); 1704 1705 return SDValue(); 1706} 1707 1708SDValue DAGCombiner::visitMUL(SDNode *N) { 1709 SDValue N0 = N->getOperand(0); 1710 SDValue N1 = N->getOperand(1); 1711 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 1712 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1713 EVT VT = N0.getValueType(); 1714 1715 // fold vector ops 1716 if (VT.isVector()) { 1717 SDValue FoldedVOp = SimplifyVBinOp(N); 1718 if (FoldedVOp.getNode()) return FoldedVOp; 1719 } 1720 1721 // fold (mul x, undef) -> 0 1722 if (N0.getOpcode() == ISD::UNDEF || N1.getOpcode() == ISD::UNDEF) 1723 return DAG.getConstant(0, VT); 1724 // fold (mul c1, c2) -> c1*c2 1725 if (N0C && N1C) 1726 return DAG.FoldConstantArithmetic(ISD::MUL, VT, N0C, N1C); 1727 // canonicalize constant to RHS 1728 if (N0C && !N1C) 1729 return DAG.getNode(ISD::MUL, N->getDebugLoc(), VT, N1, N0); 1730 // fold (mul x, 0) -> 0 1731 if (N1C && N1C->isNullValue()) 1732 return N1; 1733 // fold (mul x, -1) -> 0-x 1734 if (N1C && N1C->isAllOnesValue()) 1735 return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, 1736 DAG.getConstant(0, VT), N0); 1737 // fold (mul x, (1 << c)) -> x << c 1738 if (N1C && N1C->getAPIntValue().isPowerOf2()) 1739 return DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, N0, 1740 DAG.getConstant(N1C->getAPIntValue().logBase2(), 1741 getShiftAmountTy(N0.getValueType()))); 1742 // fold (mul x, -(1 << c)) -> -(x << c) or (-x) << c 1743 if (N1C && (-N1C->getAPIntValue()).isPowerOf2()) { 1744 unsigned Log2Val = (-N1C->getAPIntValue()).logBase2(); 1745 // FIXME: If the input is something that is easily negated (e.g. a 1746 // single-use add), we should put the negate there. 1747 return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, 1748 DAG.getConstant(0, VT), 1749 DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, N0, 1750 DAG.getConstant(Log2Val, 1751 getShiftAmountTy(N0.getValueType())))); 1752 } 1753 // (mul (shl X, c1), c2) -> (mul X, c2 << c1) 1754 if (N1C && N0.getOpcode() == ISD::SHL && 1755 isa<ConstantSDNode>(N0.getOperand(1))) { 1756 SDValue C3 = DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, 1757 N1, N0.getOperand(1)); 1758 AddToWorkList(C3.getNode()); 1759 return DAG.getNode(ISD::MUL, N->getDebugLoc(), VT, 1760 N0.getOperand(0), C3); 1761 } 1762 1763 // Change (mul (shl X, C), Y) -> (shl (mul X, Y), C) when the shift has one 1764 // use. 1765 { 1766 SDValue Sh(0,0), Y(0,0); 1767 // Check for both (mul (shl X, C), Y) and (mul Y, (shl X, C)). 1768 if (N0.getOpcode() == ISD::SHL && isa<ConstantSDNode>(N0.getOperand(1)) && 1769 N0.getNode()->hasOneUse()) { 1770 Sh = N0; Y = N1; 1771 } else if (N1.getOpcode() == ISD::SHL && 1772 isa<ConstantSDNode>(N1.getOperand(1)) && 1773 N1.getNode()->hasOneUse()) { 1774 Sh = N1; Y = N0; 1775 } 1776 1777 if (Sh.getNode()) { 1778 SDValue Mul = DAG.getNode(ISD::MUL, N->getDebugLoc(), VT, 1779 Sh.getOperand(0), Y); 1780 return DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, 1781 Mul, Sh.getOperand(1)); 1782 } 1783 } 1784 1785 // fold (mul (add x, c1), c2) -> (add (mul x, c2), c1*c2) 1786 if (N1C && N0.getOpcode() == ISD::ADD && N0.getNode()->hasOneUse() && 1787 isa<ConstantSDNode>(N0.getOperand(1))) 1788 return DAG.getNode(ISD::ADD, N->getDebugLoc(), VT, 1789 DAG.getNode(ISD::MUL, N0.getDebugLoc(), VT, 1790 N0.getOperand(0), N1), 1791 DAG.getNode(ISD::MUL, N1.getDebugLoc(), VT, 1792 N0.getOperand(1), N1)); 1793 1794 // reassociate mul 1795 SDValue RMUL = ReassociateOps(ISD::MUL, N->getDebugLoc(), N0, N1); 1796 if (RMUL.getNode() != 0) 1797 return RMUL; 1798 1799 return SDValue(); 1800} 1801 1802SDValue DAGCombiner::visitSDIV(SDNode *N) { 1803 SDValue N0 = N->getOperand(0); 1804 SDValue N1 = N->getOperand(1); 1805 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.getNode()); 1806 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.getNode()); 1807 EVT VT = N->getValueType(0); 1808 1809 // fold vector ops 1810 if (VT.isVector()) { 1811 SDValue FoldedVOp = SimplifyVBinOp(N); 1812 if (FoldedVOp.getNode()) return FoldedVOp; 1813 } 1814 1815 // fold (sdiv c1, c2) -> c1/c2 1816 if (N0C && N1C && !N1C->isNullValue()) 1817 return DAG.FoldConstantArithmetic(ISD::SDIV, VT, N0C, N1C); 1818 // fold (sdiv X, 1) -> X 1819 if (N1C && N1C->getAPIntValue() == 1LL) 1820 return N0; 1821 // fold (sdiv X, -1) -> 0-X 1822 if (N1C && N1C->isAllOnesValue()) 1823 return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, 1824 DAG.getConstant(0, VT), N0); 1825 // If we know the sign bits of both operands are zero, strength reduce to a 1826 // udiv instead. Handles (X&15) /s 4 -> X&15 >> 2 1827 if (!VT.isVector()) { 1828 if (DAG.SignBitIsZero(N1) && DAG.SignBitIsZero(N0)) 1829 return DAG.getNode(ISD::UDIV, N->getDebugLoc(), N1.getValueType(), 1830 N0, N1); 1831 } 1832 // fold (sdiv X, pow2) -> simple ops after legalize 1833 if (N1C && !N1C->isNullValue() && 1834 (N1C->getAPIntValue().isPowerOf2() || 1835 (-N1C->getAPIntValue()).isPowerOf2())) { 1836 // If dividing by powers of two is cheap, then don't perform the following 1837 // fold. 1838 if (TLI.isPow2DivCheap()) 1839 return SDValue(); 1840 1841 unsigned lg2 = N1C->getAPIntValue().countTrailingZeros(); 1842 1843 // Splat the sign bit into the register 1844 SDValue SGN = DAG.getNode(ISD::SRA, N->getDebugLoc(), VT, N0, 1845 DAG.getConstant(VT.getSizeInBits()-1, 1846 getShiftAmountTy(N0.getValueType()))); 1847 AddToWorkList(SGN.getNode()); 1848 1849 // Add (N0 < 0) ? abs2 - 1 : 0; 1850 SDValue SRL = DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, SGN, 1851 DAG.getConstant(VT.getSizeInBits() - lg2, 1852 getShiftAmountTy(SGN.getValueType()))); 1853 SDValue ADD = DAG.getNode(ISD::ADD, N->getDebugLoc(), VT, N0, SRL); 1854 AddToWorkList(SRL.getNode()); 1855 AddToWorkList(ADD.getNode()); // Divide by pow2 1856 SDValue SRA = DAG.getNode(ISD::SRA, N->getDebugLoc(), VT, ADD, 1857 DAG.getConstant(lg2, getShiftAmountTy(ADD.getValueType()))); 1858 1859 // If we're dividing by a positive value, we're done. Otherwise, we must 1860 // negate the result. 1861 if (N1C->getAPIntValue().isNonNegative()) 1862 return SRA; 1863 1864 AddToWorkList(SRA.getNode()); 1865 return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, 1866 DAG.getConstant(0, VT), SRA); 1867 } 1868 1869 // if integer divide is expensive and we satisfy the requirements, emit an 1870 // alternate sequence. 1871 if (N1C && !N1C->isNullValue() && !TLI.isIntDivCheap()) { 1872 SDValue Op = BuildSDIV(N); 1873 if (Op.getNode()) return Op; 1874 } 1875 1876 // undef / X -> 0 1877 if (N0.getOpcode() == ISD::UNDEF) 1878 return DAG.getConstant(0, VT); 1879 // X / undef -> undef 1880 if (N1.getOpcode() == ISD::UNDEF) 1881 return N1; 1882 1883 return SDValue(); 1884} 1885 1886SDValue DAGCombiner::visitUDIV(SDNode *N) { 1887 SDValue N0 = N->getOperand(0); 1888 SDValue N1 = N->getOperand(1); 1889 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.getNode()); 1890 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.getNode()); 1891 EVT VT = N->getValueType(0); 1892 1893 // fold vector ops 1894 if (VT.isVector()) { 1895 SDValue FoldedVOp = SimplifyVBinOp(N); 1896 if (FoldedVOp.getNode()) return FoldedVOp; 1897 } 1898 1899 // fold (udiv c1, c2) -> c1/c2 1900 if (N0C && N1C && !N1C->isNullValue()) 1901 return DAG.FoldConstantArithmetic(ISD::UDIV, VT, N0C, N1C); 1902 // fold (udiv x, (1 << c)) -> x >>u c 1903 if (N1C && N1C->getAPIntValue().isPowerOf2()) 1904 return DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, N0, 1905 DAG.getConstant(N1C->getAPIntValue().logBase2(), 1906 getShiftAmountTy(N0.getValueType()))); 1907 // fold (udiv x, (shl c, y)) -> x >>u (log2(c)+y) iff c is power of 2 1908 if (N1.getOpcode() == ISD::SHL) { 1909 if (ConstantSDNode *SHC = dyn_cast<ConstantSDNode>(N1.getOperand(0))) { 1910 if (SHC->getAPIntValue().isPowerOf2()) { 1911 EVT ADDVT = N1.getOperand(1).getValueType(); 1912 SDValue Add = DAG.getNode(ISD::ADD, N->getDebugLoc(), ADDVT, 1913 N1.getOperand(1), 1914 DAG.getConstant(SHC->getAPIntValue() 1915 .logBase2(), 1916 ADDVT)); 1917 AddToWorkList(Add.getNode()); 1918 return DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, N0, Add); 1919 } 1920 } 1921 } 1922 // fold (udiv x, c) -> alternate 1923 if (N1C && !N1C->isNullValue() && !TLI.isIntDivCheap()) { 1924 SDValue Op = BuildUDIV(N); 1925 if (Op.getNode()) return Op; 1926 } 1927 1928 // undef / X -> 0 1929 if (N0.getOpcode() == ISD::UNDEF) 1930 return DAG.getConstant(0, VT); 1931 // X / undef -> undef 1932 if (N1.getOpcode() == ISD::UNDEF) 1933 return N1; 1934 1935 return SDValue(); 1936} 1937 1938SDValue DAGCombiner::visitSREM(SDNode *N) { 1939 SDValue N0 = N->getOperand(0); 1940 SDValue N1 = N->getOperand(1); 1941 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 1942 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1943 EVT VT = N->getValueType(0); 1944 1945 // fold (srem c1, c2) -> c1%c2 1946 if (N0C && N1C && !N1C->isNullValue()) 1947 return DAG.FoldConstantArithmetic(ISD::SREM, VT, N0C, N1C); 1948 // If we know the sign bits of both operands are zero, strength reduce to a 1949 // urem instead. Handles (X & 0x0FFFFFFF) %s 16 -> X&15 1950 if (!VT.isVector()) { 1951 if (DAG.SignBitIsZero(N1) && DAG.SignBitIsZero(N0)) 1952 return DAG.getNode(ISD::UREM, N->getDebugLoc(), VT, N0, N1); 1953 } 1954 1955 // If X/C can be simplified by the division-by-constant logic, lower 1956 // X%C to the equivalent of X-X/C*C. 1957 if (N1C && !N1C->isNullValue()) { 1958 SDValue Div = DAG.getNode(ISD::SDIV, N->getDebugLoc(), VT, N0, N1); 1959 AddToWorkList(Div.getNode()); 1960 SDValue OptimizedDiv = combine(Div.getNode()); 1961 if (OptimizedDiv.getNode() && OptimizedDiv.getNode() != Div.getNode()) { 1962 SDValue Mul = DAG.getNode(ISD::MUL, N->getDebugLoc(), VT, 1963 OptimizedDiv, N1); 1964 SDValue Sub = DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N0, Mul); 1965 AddToWorkList(Mul.getNode()); 1966 return Sub; 1967 } 1968 } 1969 1970 // undef % X -> 0 1971 if (N0.getOpcode() == ISD::UNDEF) 1972 return DAG.getConstant(0, VT); 1973 // X % undef -> undef 1974 if (N1.getOpcode() == ISD::UNDEF) 1975 return N1; 1976 1977 return SDValue(); 1978} 1979 1980SDValue DAGCombiner::visitUREM(SDNode *N) { 1981 SDValue N0 = N->getOperand(0); 1982 SDValue N1 = N->getOperand(1); 1983 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 1984 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1985 EVT VT = N->getValueType(0); 1986 1987 // fold (urem c1, c2) -> c1%c2 1988 if (N0C && N1C && !N1C->isNullValue()) 1989 return DAG.FoldConstantArithmetic(ISD::UREM, VT, N0C, N1C); 1990 // fold (urem x, pow2) -> (and x, pow2-1) 1991 if (N1C && !N1C->isNullValue() && N1C->getAPIntValue().isPowerOf2()) 1992 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, N0, 1993 DAG.getConstant(N1C->getAPIntValue()-1,VT)); 1994 // fold (urem x, (shl pow2, y)) -> (and x, (add (shl pow2, y), -1)) 1995 if (N1.getOpcode() == ISD::SHL) { 1996 if (ConstantSDNode *SHC = dyn_cast<ConstantSDNode>(N1.getOperand(0))) { 1997 if (SHC->getAPIntValue().isPowerOf2()) { 1998 SDValue Add = 1999 DAG.getNode(ISD::ADD, N->getDebugLoc(), VT, N1, 2000 DAG.getConstant(APInt::getAllOnesValue(VT.getSizeInBits()), 2001 VT)); 2002 AddToWorkList(Add.getNode()); 2003 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, N0, Add); 2004 } 2005 } 2006 } 2007 2008 // If X/C can be simplified by the division-by-constant logic, lower 2009 // X%C to the equivalent of X-X/C*C. 2010 if (N1C && !N1C->isNullValue()) { 2011 SDValue Div = DAG.getNode(ISD::UDIV, N->getDebugLoc(), VT, N0, N1); 2012 AddToWorkList(Div.getNode()); 2013 SDValue OptimizedDiv = combine(Div.getNode()); 2014 if (OptimizedDiv.getNode() && OptimizedDiv.getNode() != Div.getNode()) { 2015 SDValue Mul = DAG.getNode(ISD::MUL, N->getDebugLoc(), VT, 2016 OptimizedDiv, N1); 2017 SDValue Sub = DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N0, Mul); 2018 AddToWorkList(Mul.getNode()); 2019 return Sub; 2020 } 2021 } 2022 2023 // undef % X -> 0 2024 if (N0.getOpcode() == ISD::UNDEF) 2025 return DAG.getConstant(0, VT); 2026 // X % undef -> undef 2027 if (N1.getOpcode() == ISD::UNDEF) 2028 return N1; 2029 2030 return SDValue(); 2031} 2032 2033SDValue DAGCombiner::visitMULHS(SDNode *N) { 2034 SDValue N0 = N->getOperand(0); 2035 SDValue N1 = N->getOperand(1); 2036 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 2037 EVT VT = N->getValueType(0); 2038 DebugLoc DL = N->getDebugLoc(); 2039 2040 // fold (mulhs x, 0) -> 0 2041 if (N1C && N1C->isNullValue()) 2042 return N1; 2043 // fold (mulhs x, 1) -> (sra x, size(x)-1) 2044 if (N1C && N1C->getAPIntValue() == 1) 2045 return DAG.getNode(ISD::SRA, N->getDebugLoc(), N0.getValueType(), N0, 2046 DAG.getConstant(N0.getValueType().getSizeInBits() - 1, 2047 getShiftAmountTy(N0.getValueType()))); 2048 // fold (mulhs x, undef) -> 0 2049 if (N0.getOpcode() == ISD::UNDEF || N1.getOpcode() == ISD::UNDEF) 2050 return DAG.getConstant(0, VT); 2051 2052 // If the type twice as wide is legal, transform the mulhs to a wider multiply 2053 // plus a shift. 2054 if (VT.isSimple() && !VT.isVector()) { 2055 MVT Simple = VT.getSimpleVT(); 2056 unsigned SimpleSize = Simple.getSizeInBits(); 2057 EVT NewVT = EVT::getIntegerVT(*DAG.getContext(), SimpleSize*2); 2058 if (TLI.isOperationLegal(ISD::MUL, NewVT)) { 2059 N0 = DAG.getNode(ISD::SIGN_EXTEND, DL, NewVT, N0); 2060 N1 = DAG.getNode(ISD::SIGN_EXTEND, DL, NewVT, N1); 2061 N1 = DAG.getNode(ISD::MUL, DL, NewVT, N0, N1); 2062 N1 = DAG.getNode(ISD::SRL, DL, NewVT, N1, 2063 DAG.getConstant(SimpleSize, getShiftAmountTy(N1.getValueType()))); 2064 return DAG.getNode(ISD::TRUNCATE, DL, VT, N1); 2065 } 2066 } 2067 2068 return SDValue(); 2069} 2070 2071SDValue DAGCombiner::visitMULHU(SDNode *N) { 2072 SDValue N0 = N->getOperand(0); 2073 SDValue N1 = N->getOperand(1); 2074 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 2075 EVT VT = N->getValueType(0); 2076 DebugLoc DL = N->getDebugLoc(); 2077 2078 // fold (mulhu x, 0) -> 0 2079 if (N1C && N1C->isNullValue()) 2080 return N1; 2081 // fold (mulhu x, 1) -> 0 2082 if (N1C && N1C->getAPIntValue() == 1) 2083 return DAG.getConstant(0, N0.getValueType()); 2084 // fold (mulhu x, undef) -> 0 2085 if (N0.getOpcode() == ISD::UNDEF || N1.getOpcode() == ISD::UNDEF) 2086 return DAG.getConstant(0, VT); 2087 2088 // If the type twice as wide is legal, transform the mulhu to a wider multiply 2089 // plus a shift. 2090 if (VT.isSimple() && !VT.isVector()) { 2091 MVT Simple = VT.getSimpleVT(); 2092 unsigned SimpleSize = Simple.getSizeInBits(); 2093 EVT NewVT = EVT::getIntegerVT(*DAG.getContext(), SimpleSize*2); 2094 if (TLI.isOperationLegal(ISD::MUL, NewVT)) { 2095 N0 = DAG.getNode(ISD::ZERO_EXTEND, DL, NewVT, N0); 2096 N1 = DAG.getNode(ISD::ZERO_EXTEND, DL, NewVT, N1); 2097 N1 = DAG.getNode(ISD::MUL, DL, NewVT, N0, N1); 2098 N1 = DAG.getNode(ISD::SRL, DL, NewVT, N1, 2099 DAG.getConstant(SimpleSize, getShiftAmountTy(N1.getValueType()))); 2100 return DAG.getNode(ISD::TRUNCATE, DL, VT, N1); 2101 } 2102 } 2103 2104 return SDValue(); 2105} 2106 2107/// SimplifyNodeWithTwoResults - Perform optimizations common to nodes that 2108/// compute two values. LoOp and HiOp give the opcodes for the two computations 2109/// that are being performed. Return true if a simplification was made. 2110/// 2111SDValue DAGCombiner::SimplifyNodeWithTwoResults(SDNode *N, unsigned LoOp, 2112 unsigned HiOp) { 2113 // If the high half is not needed, just compute the low half. 2114 bool HiExists = N->hasAnyUseOfValue(1); 2115 if (!HiExists && 2116 (!LegalOperations || 2117 TLI.isOperationLegal(LoOp, N->getValueType(0)))) { 2118 SDValue Res = DAG.getNode(LoOp, N->getDebugLoc(), N->getValueType(0), 2119 N->op_begin(), N->getNumOperands()); 2120 return CombineTo(N, Res, Res); 2121 } 2122 2123 // If the low half is not needed, just compute the high half. 2124 bool LoExists = N->hasAnyUseOfValue(0); 2125 if (!LoExists && 2126 (!LegalOperations || 2127 TLI.isOperationLegal(HiOp, N->getValueType(1)))) { 2128 SDValue Res = DAG.getNode(HiOp, N->getDebugLoc(), N->getValueType(1), 2129 N->op_begin(), N->getNumOperands()); 2130 return CombineTo(N, Res, Res); 2131 } 2132 2133 // If both halves are used, return as it is. 2134 if (LoExists && HiExists) 2135 return SDValue(); 2136 2137 // If the two computed results can be simplified separately, separate them. 2138 if (LoExists) { 2139 SDValue Lo = DAG.getNode(LoOp, N->getDebugLoc(), N->getValueType(0), 2140 N->op_begin(), N->getNumOperands()); 2141 AddToWorkList(Lo.getNode()); 2142 SDValue LoOpt = combine(Lo.getNode()); 2143 if (LoOpt.getNode() && LoOpt.getNode() != Lo.getNode() && 2144 (!LegalOperations || 2145 TLI.isOperationLegal(LoOpt.getOpcode(), LoOpt.getValueType()))) 2146 return CombineTo(N, LoOpt, LoOpt); 2147 } 2148 2149 if (HiExists) { 2150 SDValue Hi = DAG.getNode(HiOp, N->getDebugLoc(), N->getValueType(1), 2151 N->op_begin(), N->getNumOperands()); 2152 AddToWorkList(Hi.getNode()); 2153 SDValue HiOpt = combine(Hi.getNode()); 2154 if (HiOpt.getNode() && HiOpt != Hi && 2155 (!LegalOperations || 2156 TLI.isOperationLegal(HiOpt.getOpcode(), HiOpt.getValueType()))) 2157 return CombineTo(N, HiOpt, HiOpt); 2158 } 2159 2160 return SDValue(); 2161} 2162 2163SDValue DAGCombiner::visitSMUL_LOHI(SDNode *N) { 2164 SDValue Res = SimplifyNodeWithTwoResults(N, ISD::MUL, ISD::MULHS); 2165 if (Res.getNode()) return Res; 2166 2167 EVT VT = N->getValueType(0); 2168 DebugLoc DL = N->getDebugLoc(); 2169 2170 // If the type twice as wide is legal, transform the mulhu to a wider multiply 2171 // plus a shift. 2172 if (VT.isSimple() && !VT.isVector()) { 2173 MVT Simple = VT.getSimpleVT(); 2174 unsigned SimpleSize = Simple.getSizeInBits(); 2175 EVT NewVT = EVT::getIntegerVT(*DAG.getContext(), SimpleSize*2); 2176 if (TLI.isOperationLegal(ISD::MUL, NewVT)) { 2177 SDValue Lo = DAG.getNode(ISD::SIGN_EXTEND, DL, NewVT, N->getOperand(0)); 2178 SDValue Hi = DAG.getNode(ISD::SIGN_EXTEND, DL, NewVT, N->getOperand(1)); 2179 Lo = DAG.getNode(ISD::MUL, DL, NewVT, Lo, Hi); 2180 // Compute the high part as N1. 2181 Hi = DAG.getNode(ISD::SRL, DL, NewVT, Lo, 2182 DAG.getConstant(SimpleSize, getShiftAmountTy(Lo.getValueType()))); 2183 Hi = DAG.getNode(ISD::TRUNCATE, DL, VT, Hi); 2184 // Compute the low part as N0. 2185 Lo = DAG.getNode(ISD::TRUNCATE, DL, VT, Lo); 2186 return CombineTo(N, Lo, Hi); 2187 } 2188 } 2189 2190 return SDValue(); 2191} 2192 2193SDValue DAGCombiner::visitUMUL_LOHI(SDNode *N) { 2194 SDValue Res = SimplifyNodeWithTwoResults(N, ISD::MUL, ISD::MULHU); 2195 if (Res.getNode()) return Res; 2196 2197 EVT VT = N->getValueType(0); 2198 DebugLoc DL = N->getDebugLoc(); 2199 2200 // If the type twice as wide is legal, transform the mulhu to a wider multiply 2201 // plus a shift. 2202 if (VT.isSimple() && !VT.isVector()) { 2203 MVT Simple = VT.getSimpleVT(); 2204 unsigned SimpleSize = Simple.getSizeInBits(); 2205 EVT NewVT = EVT::getIntegerVT(*DAG.getContext(), SimpleSize*2); 2206 if (TLI.isOperationLegal(ISD::MUL, NewVT)) { 2207 SDValue Lo = DAG.getNode(ISD::ZERO_EXTEND, DL, NewVT, N->getOperand(0)); 2208 SDValue Hi = DAG.getNode(ISD::ZERO_EXTEND, DL, NewVT, N->getOperand(1)); 2209 Lo = DAG.getNode(ISD::MUL, DL, NewVT, Lo, Hi); 2210 // Compute the high part as N1. 2211 Hi = DAG.getNode(ISD::SRL, DL, NewVT, Lo, 2212 DAG.getConstant(SimpleSize, getShiftAmountTy(Lo.getValueType()))); 2213 Hi = DAG.getNode(ISD::TRUNCATE, DL, VT, Hi); 2214 // Compute the low part as N0. 2215 Lo = DAG.getNode(ISD::TRUNCATE, DL, VT, Lo); 2216 return CombineTo(N, Lo, Hi); 2217 } 2218 } 2219 2220 return SDValue(); 2221} 2222 2223SDValue DAGCombiner::visitSMULO(SDNode *N) { 2224 // (smulo x, 2) -> (saddo x, x) 2225 if (ConstantSDNode *C2 = dyn_cast<ConstantSDNode>(N->getOperand(1))) 2226 if (C2->getAPIntValue() == 2) 2227 return DAG.getNode(ISD::SADDO, N->getDebugLoc(), N->getVTList(), 2228 N->getOperand(0), N->getOperand(0)); 2229 2230 return SDValue(); 2231} 2232 2233SDValue DAGCombiner::visitUMULO(SDNode *N) { 2234 // (umulo x, 2) -> (uaddo x, x) 2235 if (ConstantSDNode *C2 = dyn_cast<ConstantSDNode>(N->getOperand(1))) 2236 if (C2->getAPIntValue() == 2) 2237 return DAG.getNode(ISD::UADDO, N->getDebugLoc(), N->getVTList(), 2238 N->getOperand(0), N->getOperand(0)); 2239 2240 return SDValue(); 2241} 2242 2243SDValue DAGCombiner::visitSDIVREM(SDNode *N) { 2244 SDValue Res = SimplifyNodeWithTwoResults(N, ISD::SDIV, ISD::SREM); 2245 if (Res.getNode()) return Res; 2246 2247 return SDValue(); 2248} 2249 2250SDValue DAGCombiner::visitUDIVREM(SDNode *N) { 2251 SDValue Res = SimplifyNodeWithTwoResults(N, ISD::UDIV, ISD::UREM); 2252 if (Res.getNode()) return Res; 2253 2254 return SDValue(); 2255} 2256 2257/// SimplifyBinOpWithSameOpcodeHands - If this is a binary operator with 2258/// two operands of the same opcode, try to simplify it. 2259SDValue DAGCombiner::SimplifyBinOpWithSameOpcodeHands(SDNode *N) { 2260 SDValue N0 = N->getOperand(0), N1 = N->getOperand(1); 2261 EVT VT = N0.getValueType(); 2262 assert(N0.getOpcode() == N1.getOpcode() && "Bad input!"); 2263 2264 // Bail early if none of these transforms apply. 2265 if (N0.getNode()->getNumOperands() == 0) return SDValue(); 2266 2267 // For each of OP in AND/OR/XOR: 2268 // fold (OP (zext x), (zext y)) -> (zext (OP x, y)) 2269 // fold (OP (sext x), (sext y)) -> (sext (OP x, y)) 2270 // fold (OP (aext x), (aext y)) -> (aext (OP x, y)) 2271 // fold (OP (trunc x), (trunc y)) -> (trunc (OP x, y)) (if trunc isn't free) 2272 // 2273 // do not sink logical op inside of a vector extend, since it may combine 2274 // into a vsetcc. 2275 EVT Op0VT = N0.getOperand(0).getValueType(); 2276 if ((N0.getOpcode() == ISD::ZERO_EXTEND || 2277 N0.getOpcode() == ISD::SIGN_EXTEND || 2278 // Avoid infinite looping with PromoteIntBinOp. 2279 (N0.getOpcode() == ISD::ANY_EXTEND && 2280 (!LegalTypes || TLI.isTypeDesirableForOp(N->getOpcode(), Op0VT))) || 2281 (N0.getOpcode() == ISD::TRUNCATE && 2282 (!TLI.isZExtFree(VT, Op0VT) || 2283 !TLI.isTruncateFree(Op0VT, VT)) && 2284 TLI.isTypeLegal(Op0VT))) && 2285 !VT.isVector() && 2286 Op0VT == N1.getOperand(0).getValueType() && 2287 (!LegalOperations || TLI.isOperationLegal(N->getOpcode(), Op0VT))) { 2288 SDValue ORNode = DAG.getNode(N->getOpcode(), N0.getDebugLoc(), 2289 N0.getOperand(0).getValueType(), 2290 N0.getOperand(0), N1.getOperand(0)); 2291 AddToWorkList(ORNode.getNode()); 2292 return DAG.getNode(N0.getOpcode(), N->getDebugLoc(), VT, ORNode); 2293 } 2294 2295 // For each of OP in SHL/SRL/SRA/AND... 2296 // fold (and (OP x, z), (OP y, z)) -> (OP (and x, y), z) 2297 // fold (or (OP x, z), (OP y, z)) -> (OP (or x, y), z) 2298 // fold (xor (OP x, z), (OP y, z)) -> (OP (xor x, y), z) 2299 if ((N0.getOpcode() == ISD::SHL || N0.getOpcode() == ISD::SRL || 2300 N0.getOpcode() == ISD::SRA || N0.getOpcode() == ISD::AND) && 2301 N0.getOperand(1) == N1.getOperand(1)) { 2302 SDValue ORNode = DAG.getNode(N->getOpcode(), N0.getDebugLoc(), 2303 N0.getOperand(0).getValueType(), 2304 N0.getOperand(0), N1.getOperand(0)); 2305 AddToWorkList(ORNode.getNode()); 2306 return DAG.getNode(N0.getOpcode(), N->getDebugLoc(), VT, 2307 ORNode, N0.getOperand(1)); 2308 } 2309 2310 return SDValue(); 2311} 2312 2313SDValue DAGCombiner::visitAND(SDNode *N) { 2314 SDValue N0 = N->getOperand(0); 2315 SDValue N1 = N->getOperand(1); 2316 SDValue LL, LR, RL, RR, CC0, CC1; 2317 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 2318 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 2319 EVT VT = N1.getValueType(); 2320 unsigned BitWidth = VT.getScalarType().getSizeInBits(); 2321 2322 // fold vector ops 2323 if (VT.isVector()) { 2324 SDValue FoldedVOp = SimplifyVBinOp(N); 2325 if (FoldedVOp.getNode()) return FoldedVOp; 2326 } 2327 2328 // fold (and x, undef) -> 0 2329 if (N0.getOpcode() == ISD::UNDEF || N1.getOpcode() == ISD::UNDEF) 2330 return DAG.getConstant(0, VT); 2331 // fold (and c1, c2) -> c1&c2 2332 if (N0C && N1C) 2333 return DAG.FoldConstantArithmetic(ISD::AND, VT, N0C, N1C); 2334 // canonicalize constant to RHS 2335 if (N0C && !N1C) 2336 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, N1, N0); 2337 // fold (and x, -1) -> x 2338 if (N1C && N1C->isAllOnesValue()) 2339 return N0; 2340 // if (and x, c) is known to be zero, return 0 2341 if (N1C && DAG.MaskedValueIsZero(SDValue(N, 0), 2342 APInt::getAllOnesValue(BitWidth))) 2343 return DAG.getConstant(0, VT); 2344 // reassociate and 2345 SDValue RAND = ReassociateOps(ISD::AND, N->getDebugLoc(), N0, N1); 2346 if (RAND.getNode() != 0) 2347 return RAND; 2348 // fold (and (or x, C), D) -> D if (C & D) == D 2349 if (N1C && N0.getOpcode() == ISD::OR) 2350 if (ConstantSDNode *ORI = dyn_cast<ConstantSDNode>(N0.getOperand(1))) 2351 if ((ORI->getAPIntValue() & N1C->getAPIntValue()) == N1C->getAPIntValue()) 2352 return N1; 2353 // fold (and (any_ext V), c) -> (zero_ext V) if 'and' only clears top bits. 2354 if (N1C && N0.getOpcode() == ISD::ANY_EXTEND) { 2355 SDValue N0Op0 = N0.getOperand(0); 2356 APInt Mask = ~N1C->getAPIntValue(); 2357 Mask = Mask.trunc(N0Op0.getValueSizeInBits()); 2358 if (DAG.MaskedValueIsZero(N0Op0, Mask)) { 2359 SDValue Zext = DAG.getNode(ISD::ZERO_EXTEND, N->getDebugLoc(), 2360 N0.getValueType(), N0Op0); 2361 2362 // Replace uses of the AND with uses of the Zero extend node. 2363 CombineTo(N, Zext); 2364 2365 // We actually want to replace all uses of the any_extend with the 2366 // zero_extend, to avoid duplicating things. This will later cause this 2367 // AND to be folded. 2368 CombineTo(N0.getNode(), Zext); 2369 return SDValue(N, 0); // Return N so it doesn't get rechecked! 2370 } 2371 } 2372 // fold (and (setcc x), (setcc y)) -> (setcc (and x, y)) 2373 if (isSetCCEquivalent(N0, LL, LR, CC0) && isSetCCEquivalent(N1, RL, RR, CC1)){ 2374 ISD::CondCode Op0 = cast<CondCodeSDNode>(CC0)->get(); 2375 ISD::CondCode Op1 = cast<CondCodeSDNode>(CC1)->get(); 2376 2377 if (LR == RR && isa<ConstantSDNode>(LR) && Op0 == Op1 && 2378 LL.getValueType().isInteger()) { 2379 // fold (and (seteq X, 0), (seteq Y, 0)) -> (seteq (or X, Y), 0) 2380 if (cast<ConstantSDNode>(LR)->isNullValue() && Op1 == ISD::SETEQ) { 2381 SDValue ORNode = DAG.getNode(ISD::OR, N0.getDebugLoc(), 2382 LR.getValueType(), LL, RL); 2383 AddToWorkList(ORNode.getNode()); 2384 return DAG.getSetCC(N->getDebugLoc(), VT, ORNode, LR, Op1); 2385 } 2386 // fold (and (seteq X, -1), (seteq Y, -1)) -> (seteq (and X, Y), -1) 2387 if (cast<ConstantSDNode>(LR)->isAllOnesValue() && Op1 == ISD::SETEQ) { 2388 SDValue ANDNode = DAG.getNode(ISD::AND, N0.getDebugLoc(), 2389 LR.getValueType(), LL, RL); 2390 AddToWorkList(ANDNode.getNode()); 2391 return DAG.getSetCC(N->getDebugLoc(), VT, ANDNode, LR, Op1); 2392 } 2393 // fold (and (setgt X, -1), (setgt Y, -1)) -> (setgt (or X, Y), -1) 2394 if (cast<ConstantSDNode>(LR)->isAllOnesValue() && Op1 == ISD::SETGT) { 2395 SDValue ORNode = DAG.getNode(ISD::OR, N0.getDebugLoc(), 2396 LR.getValueType(), LL, RL); 2397 AddToWorkList(ORNode.getNode()); 2398 return DAG.getSetCC(N->getDebugLoc(), VT, ORNode, LR, Op1); 2399 } 2400 } 2401 // canonicalize equivalent to ll == rl 2402 if (LL == RR && LR == RL) { 2403 Op1 = ISD::getSetCCSwappedOperands(Op1); 2404 std::swap(RL, RR); 2405 } 2406 if (LL == RL && LR == RR) { 2407 bool isInteger = LL.getValueType().isInteger(); 2408 ISD::CondCode Result = ISD::getSetCCAndOperation(Op0, Op1, isInteger); 2409 if (Result != ISD::SETCC_INVALID && 2410 (!LegalOperations || TLI.isCondCodeLegal(Result, LL.getValueType()))) 2411 return DAG.getSetCC(N->getDebugLoc(), N0.getValueType(), 2412 LL, LR, Result); 2413 } 2414 } 2415 2416 // Simplify: (and (op x...), (op y...)) -> (op (and x, y)) 2417 if (N0.getOpcode() == N1.getOpcode()) { 2418 SDValue Tmp = SimplifyBinOpWithSameOpcodeHands(N); 2419 if (Tmp.getNode()) return Tmp; 2420 } 2421 2422 // fold (and (sign_extend_inreg x, i16 to i32), 1) -> (and x, 1) 2423 // fold (and (sra)) -> (and (srl)) when possible. 2424 if (!VT.isVector() && 2425 SimplifyDemandedBits(SDValue(N, 0))) 2426 return SDValue(N, 0); 2427 2428 // fold (zext_inreg (extload x)) -> (zextload x) 2429 if (ISD::isEXTLoad(N0.getNode()) && ISD::isUNINDEXEDLoad(N0.getNode())) { 2430 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 2431 EVT MemVT = LN0->getMemoryVT(); 2432 // If we zero all the possible extended bits, then we can turn this into 2433 // a zextload if we are running before legalize or the operation is legal. 2434 unsigned BitWidth = N1.getValueType().getScalarType().getSizeInBits(); 2435 if (DAG.MaskedValueIsZero(N1, APInt::getHighBitsSet(BitWidth, 2436 BitWidth - MemVT.getScalarType().getSizeInBits())) && 2437 ((!LegalOperations && !LN0->isVolatile()) || 2438 TLI.isLoadExtLegal(ISD::ZEXTLOAD, MemVT))) { 2439 SDValue ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, N0.getDebugLoc(), VT, 2440 LN0->getChain(), LN0->getBasePtr(), 2441 LN0->getPointerInfo(), MemVT, 2442 LN0->isVolatile(), LN0->isNonTemporal(), 2443 LN0->getAlignment()); 2444 AddToWorkList(N); 2445 CombineTo(N0.getNode(), ExtLoad, ExtLoad.getValue(1)); 2446 return SDValue(N, 0); // Return N so it doesn't get rechecked! 2447 } 2448 } 2449 // fold (zext_inreg (sextload x)) -> (zextload x) iff load has one use 2450 if (ISD::isSEXTLoad(N0.getNode()) && ISD::isUNINDEXEDLoad(N0.getNode()) && 2451 N0.hasOneUse()) { 2452 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 2453 EVT MemVT = LN0->getMemoryVT(); 2454 // If we zero all the possible extended bits, then we can turn this into 2455 // a zextload if we are running before legalize or the operation is legal. 2456 unsigned BitWidth = N1.getValueType().getScalarType().getSizeInBits(); 2457 if (DAG.MaskedValueIsZero(N1, APInt::getHighBitsSet(BitWidth, 2458 BitWidth - MemVT.getScalarType().getSizeInBits())) && 2459 ((!LegalOperations && !LN0->isVolatile()) || 2460 TLI.isLoadExtLegal(ISD::ZEXTLOAD, MemVT))) { 2461 SDValue ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, N0.getDebugLoc(), VT, 2462 LN0->getChain(), 2463 LN0->getBasePtr(), LN0->getPointerInfo(), 2464 MemVT, 2465 LN0->isVolatile(), LN0->isNonTemporal(), 2466 LN0->getAlignment()); 2467 AddToWorkList(N); 2468 CombineTo(N0.getNode(), ExtLoad, ExtLoad.getValue(1)); 2469 return SDValue(N, 0); // Return N so it doesn't get rechecked! 2470 } 2471 } 2472 2473 // fold (and (load x), 255) -> (zextload x, i8) 2474 // fold (and (extload x, i16), 255) -> (zextload x, i8) 2475 // fold (and (any_ext (extload x, i16)), 255) -> (zextload x, i8) 2476 if (N1C && (N0.getOpcode() == ISD::LOAD || 2477 (N0.getOpcode() == ISD::ANY_EXTEND && 2478 N0.getOperand(0).getOpcode() == ISD::LOAD))) { 2479 bool HasAnyExt = N0.getOpcode() == ISD::ANY_EXTEND; 2480 LoadSDNode *LN0 = HasAnyExt 2481 ? cast<LoadSDNode>(N0.getOperand(0)) 2482 : cast<LoadSDNode>(N0); 2483 if (LN0->getExtensionType() != ISD::SEXTLOAD && 2484 LN0->isUnindexed() && N0.hasOneUse() && LN0->hasOneUse()) { 2485 uint32_t ActiveBits = N1C->getAPIntValue().getActiveBits(); 2486 if (ActiveBits > 0 && APIntOps::isMask(ActiveBits, N1C->getAPIntValue())){ 2487 EVT ExtVT = EVT::getIntegerVT(*DAG.getContext(), ActiveBits); 2488 EVT LoadedVT = LN0->getMemoryVT(); 2489 2490 if (ExtVT == LoadedVT && 2491 (!LegalOperations || TLI.isLoadExtLegal(ISD::ZEXTLOAD, ExtVT))) { 2492 EVT LoadResultTy = HasAnyExt ? LN0->getValueType(0) : VT; 2493 2494 SDValue NewLoad = 2495 DAG.getExtLoad(ISD::ZEXTLOAD, LN0->getDebugLoc(), LoadResultTy, 2496 LN0->getChain(), LN0->getBasePtr(), 2497 LN0->getPointerInfo(), 2498 ExtVT, LN0->isVolatile(), LN0->isNonTemporal(), 2499 LN0->getAlignment()); 2500 AddToWorkList(N); 2501 CombineTo(LN0, NewLoad, NewLoad.getValue(1)); 2502 return SDValue(N, 0); // Return N so it doesn't get rechecked! 2503 } 2504 2505 // Do not change the width of a volatile load. 2506 // Do not generate loads of non-round integer types since these can 2507 // be expensive (and would be wrong if the type is not byte sized). 2508 if (!LN0->isVolatile() && LoadedVT.bitsGT(ExtVT) && ExtVT.isRound() && 2509 (!LegalOperations || TLI.isLoadExtLegal(ISD::ZEXTLOAD, ExtVT))) { 2510 EVT PtrType = LN0->getOperand(1).getValueType(); 2511 2512 unsigned Alignment = LN0->getAlignment(); 2513 SDValue NewPtr = LN0->getBasePtr(); 2514 2515 // For big endian targets, we need to add an offset to the pointer 2516 // to load the correct bytes. For little endian systems, we merely 2517 // need to read fewer bytes from the same pointer. 2518 if (TLI.isBigEndian()) { 2519 unsigned LVTStoreBytes = LoadedVT.getStoreSize(); 2520 unsigned EVTStoreBytes = ExtVT.getStoreSize(); 2521 unsigned PtrOff = LVTStoreBytes - EVTStoreBytes; 2522 NewPtr = DAG.getNode(ISD::ADD, LN0->getDebugLoc(), PtrType, 2523 NewPtr, DAG.getConstant(PtrOff, PtrType)); 2524 Alignment = MinAlign(Alignment, PtrOff); 2525 } 2526 2527 AddToWorkList(NewPtr.getNode()); 2528 2529 EVT LoadResultTy = HasAnyExt ? LN0->getValueType(0) : VT; 2530 SDValue Load = 2531 DAG.getExtLoad(ISD::ZEXTLOAD, LN0->getDebugLoc(), LoadResultTy, 2532 LN0->getChain(), NewPtr, 2533 LN0->getPointerInfo(), 2534 ExtVT, LN0->isVolatile(), LN0->isNonTemporal(), 2535 Alignment); 2536 AddToWorkList(N); 2537 CombineTo(LN0, Load, Load.getValue(1)); 2538 return SDValue(N, 0); // Return N so it doesn't get rechecked! 2539 } 2540 } 2541 } 2542 } 2543 2544 return SDValue(); 2545} 2546 2547/// MatchBSwapHWord - Match (a >> 8) | (a << 8) as (bswap a) >> 16 2548/// 2549SDValue DAGCombiner::MatchBSwapHWordLow(SDNode *N, SDValue N0, SDValue N1, 2550 bool DemandHighBits) { 2551 if (!LegalOperations) 2552 return SDValue(); 2553 2554 EVT VT = N->getValueType(0); 2555 if (VT != MVT::i64 && VT != MVT::i32 && VT != MVT::i16) 2556 return SDValue(); 2557 if (!TLI.isOperationLegal(ISD::BSWAP, VT)) 2558 return SDValue(); 2559 2560 // Recognize (and (shl a, 8), 0xff), (and (srl a, 8), 0xff00) 2561 bool LookPassAnd0 = false; 2562 bool LookPassAnd1 = false; 2563 if (N0.getOpcode() == ISD::AND && N0.getOperand(0).getOpcode() == ISD::SRL) 2564 std::swap(N0, N1); 2565 if (N1.getOpcode() == ISD::AND && N1.getOperand(0).getOpcode() == ISD::SHL) 2566 std::swap(N0, N1); 2567 if (N0.getOpcode() == ISD::AND) { 2568 if (!N0.getNode()->hasOneUse()) 2569 return SDValue(); 2570 ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N0.getOperand(1)); 2571 if (!N01C || N01C->getZExtValue() != 0xFF00) 2572 return SDValue(); 2573 N0 = N0.getOperand(0); 2574 LookPassAnd0 = true; 2575 } 2576 2577 if (N1.getOpcode() == ISD::AND) { 2578 if (!N1.getNode()->hasOneUse()) 2579 return SDValue(); 2580 ConstantSDNode *N11C = dyn_cast<ConstantSDNode>(N1.getOperand(1)); 2581 if (!N11C || N11C->getZExtValue() != 0xFF) 2582 return SDValue(); 2583 N1 = N1.getOperand(0); 2584 LookPassAnd1 = true; 2585 } 2586 2587 if (N0.getOpcode() == ISD::SRL && N1.getOpcode() == ISD::SHL) 2588 std::swap(N0, N1); 2589 if (N0.getOpcode() != ISD::SHL || N1.getOpcode() != ISD::SRL) 2590 return SDValue(); 2591 if (!N0.getNode()->hasOneUse() || 2592 !N1.getNode()->hasOneUse()) 2593 return SDValue(); 2594 2595 ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N0.getOperand(1)); 2596 ConstantSDNode *N11C = dyn_cast<ConstantSDNode>(N1.getOperand(1)); 2597 if (!N01C || !N11C) 2598 return SDValue(); 2599 if (N01C->getZExtValue() != 8 || N11C->getZExtValue() != 8) 2600 return SDValue(); 2601 2602 // Look for (shl (and a, 0xff), 8), (srl (and a, 0xff00), 8) 2603 SDValue N00 = N0->getOperand(0); 2604 if (!LookPassAnd0 && N00.getOpcode() == ISD::AND) { 2605 if (!N00.getNode()->hasOneUse()) 2606 return SDValue(); 2607 ConstantSDNode *N001C = dyn_cast<ConstantSDNode>(N00.getOperand(1)); 2608 if (!N001C || N001C->getZExtValue() != 0xFF) 2609 return SDValue(); 2610 N00 = N00.getOperand(0); 2611 LookPassAnd0 = true; 2612 } 2613 2614 SDValue N10 = N1->getOperand(0); 2615 if (!LookPassAnd1 && N10.getOpcode() == ISD::AND) { 2616 if (!N10.getNode()->hasOneUse()) 2617 return SDValue(); 2618 ConstantSDNode *N101C = dyn_cast<ConstantSDNode>(N10.getOperand(1)); 2619 if (!N101C || N101C->getZExtValue() != 0xFF00) 2620 return SDValue(); 2621 N10 = N10.getOperand(0); 2622 LookPassAnd1 = true; 2623 } 2624 2625 if (N00 != N10) 2626 return SDValue(); 2627 2628 // Make sure everything beyond the low halfword is zero since the SRL 16 2629 // will clear the top bits. 2630 unsigned OpSizeInBits = VT.getSizeInBits(); 2631 if (DemandHighBits && OpSizeInBits > 16 && 2632 (!LookPassAnd0 || !LookPassAnd1) && 2633 !DAG.MaskedValueIsZero(N10, APInt::getHighBitsSet(OpSizeInBits, 16))) 2634 return SDValue(); 2635 2636 SDValue Res = DAG.getNode(ISD::BSWAP, N->getDebugLoc(), VT, N00); 2637 if (OpSizeInBits > 16) 2638 Res = DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, Res, 2639 DAG.getConstant(OpSizeInBits-16, getShiftAmountTy(VT))); 2640 return Res; 2641} 2642 2643/// isBSwapHWordElement - Return true if the specified node is an element 2644/// that makes up a 32-bit packed halfword byteswap. i.e. 2645/// ((x&0xff)<<8)|((x&0xff00)>>8)|((x&0x00ff0000)<<8)|((x&0xff000000)>>8) 2646static bool isBSwapHWordElement(SDValue N, SmallVector<SDNode*,4> &Parts) { 2647 if (!N.getNode()->hasOneUse()) 2648 return false; 2649 2650 unsigned Opc = N.getOpcode(); 2651 if (Opc != ISD::AND && Opc != ISD::SHL && Opc != ISD::SRL) 2652 return false; 2653 2654 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N.getOperand(1)); 2655 if (!N1C) 2656 return false; 2657 2658 unsigned Num; 2659 switch (N1C->getZExtValue()) { 2660 default: 2661 return false; 2662 case 0xFF: Num = 0; break; 2663 case 0xFF00: Num = 1; break; 2664 case 0xFF0000: Num = 2; break; 2665 case 0xFF000000: Num = 3; break; 2666 } 2667 2668 // Look for (x & 0xff) << 8 as well as ((x << 8) & 0xff00). 2669 SDValue N0 = N.getOperand(0); 2670 if (Opc == ISD::AND) { 2671 if (Num == 0 || Num == 2) { 2672 // (x >> 8) & 0xff 2673 // (x >> 8) & 0xff0000 2674 if (N0.getOpcode() != ISD::SRL) 2675 return false; 2676 ConstantSDNode *C = dyn_cast<ConstantSDNode>(N0.getOperand(1)); 2677 if (!C || C->getZExtValue() != 8) 2678 return false; 2679 } else { 2680 // (x << 8) & 0xff00 2681 // (x << 8) & 0xff000000 2682 if (N0.getOpcode() != ISD::SHL) 2683 return false; 2684 ConstantSDNode *C = dyn_cast<ConstantSDNode>(N0.getOperand(1)); 2685 if (!C || C->getZExtValue() != 8) 2686 return false; 2687 } 2688 } else if (Opc == ISD::SHL) { 2689 // (x & 0xff) << 8 2690 // (x & 0xff0000) << 8 2691 if (Num != 0 && Num != 2) 2692 return false; 2693 ConstantSDNode *C = dyn_cast<ConstantSDNode>(N.getOperand(1)); 2694 if (!C || C->getZExtValue() != 8) 2695 return false; 2696 } else { // Opc == ISD::SRL 2697 // (x & 0xff00) >> 8 2698 // (x & 0xff000000) >> 8 2699 if (Num != 1 && Num != 3) 2700 return false; 2701 ConstantSDNode *C = dyn_cast<ConstantSDNode>(N.getOperand(1)); 2702 if (!C || C->getZExtValue() != 8) 2703 return false; 2704 } 2705 2706 if (Parts[Num]) 2707 return false; 2708 2709 Parts[Num] = N0.getOperand(0).getNode(); 2710 return true; 2711} 2712 2713/// MatchBSwapHWord - Match a 32-bit packed halfword bswap. That is 2714/// ((x&0xff)<<8)|((x&0xff00)>>8)|((x&0x00ff0000)<<8)|((x&0xff000000)>>8) 2715/// => (rotl (bswap x), 16) 2716SDValue DAGCombiner::MatchBSwapHWord(SDNode *N, SDValue N0, SDValue N1) { 2717 if (!LegalOperations) 2718 return SDValue(); 2719 2720 EVT VT = N->getValueType(0); 2721 if (VT != MVT::i32) 2722 return SDValue(); 2723 if (!TLI.isOperationLegal(ISD::BSWAP, VT)) 2724 return SDValue(); 2725 2726 SmallVector<SDNode*,4> Parts(4, (SDNode*)0); 2727 // Look for either 2728 // (or (or (and), (and)), (or (and), (and))) 2729 // (or (or (or (and), (and)), (and)), (and)) 2730 if (N0.getOpcode() != ISD::OR) 2731 return SDValue(); 2732 SDValue N00 = N0.getOperand(0); 2733 SDValue N01 = N0.getOperand(1); 2734 2735 if (N1.getOpcode() == ISD::OR) { 2736 // (or (or (and), (and)), (or (and), (and))) 2737 SDValue N000 = N00.getOperand(0); 2738 if (!isBSwapHWordElement(N000, Parts)) 2739 return SDValue(); 2740 2741 SDValue N001 = N00.getOperand(1); 2742 if (!isBSwapHWordElement(N001, Parts)) 2743 return SDValue(); 2744 SDValue N010 = N01.getOperand(0); 2745 if (!isBSwapHWordElement(N010, Parts)) 2746 return SDValue(); 2747 SDValue N011 = N01.getOperand(1); 2748 if (!isBSwapHWordElement(N011, Parts)) 2749 return SDValue(); 2750 } else { 2751 // (or (or (or (and), (and)), (and)), (and)) 2752 if (!isBSwapHWordElement(N1, Parts)) 2753 return SDValue(); 2754 if (!isBSwapHWordElement(N01, Parts)) 2755 return SDValue(); 2756 if (N00.getOpcode() != ISD::OR) 2757 return SDValue(); 2758 SDValue N000 = N00.getOperand(0); 2759 if (!isBSwapHWordElement(N000, Parts)) 2760 return SDValue(); 2761 SDValue N001 = N00.getOperand(1); 2762 if (!isBSwapHWordElement(N001, Parts)) 2763 return SDValue(); 2764 } 2765 2766 // Make sure the parts are all coming from the same node. 2767 if (Parts[0] != Parts[1] || Parts[0] != Parts[2] || Parts[0] != Parts[3]) 2768 return SDValue(); 2769 2770 SDValue BSwap = DAG.getNode(ISD::BSWAP, N->getDebugLoc(), VT, 2771 SDValue(Parts[0],0)); 2772 2773 // Result of the bswap should be rotated by 16. If it's not legal, than 2774 // do (x << 16) | (x >> 16). 2775 SDValue ShAmt = DAG.getConstant(16, getShiftAmountTy(VT)); 2776 if (TLI.isOperationLegalOrCustom(ISD::ROTL, VT)) 2777 return DAG.getNode(ISD::ROTL, N->getDebugLoc(), VT, BSwap, ShAmt); 2778 else if (TLI.isOperationLegalOrCustom(ISD::ROTR, VT)) 2779 return DAG.getNode(ISD::ROTR, N->getDebugLoc(), VT, BSwap, ShAmt); 2780 return DAG.getNode(ISD::OR, N->getDebugLoc(), VT, 2781 DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, BSwap, ShAmt), 2782 DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, BSwap, ShAmt)); 2783} 2784 2785SDValue DAGCombiner::visitOR(SDNode *N) { 2786 SDValue N0 = N->getOperand(0); 2787 SDValue N1 = N->getOperand(1); 2788 SDValue LL, LR, RL, RR, CC0, CC1; 2789 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 2790 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 2791 EVT VT = N1.getValueType(); 2792 2793 // fold vector ops 2794 if (VT.isVector()) { 2795 SDValue FoldedVOp = SimplifyVBinOp(N); 2796 if (FoldedVOp.getNode()) return FoldedVOp; 2797 } 2798 2799 // fold (or x, undef) -> -1 2800 if (!LegalOperations && 2801 (N0.getOpcode() == ISD::UNDEF || N1.getOpcode() == ISD::UNDEF)) { 2802 EVT EltVT = VT.isVector() ? VT.getVectorElementType() : VT; 2803 return DAG.getConstant(APInt::getAllOnesValue(EltVT.getSizeInBits()), VT); 2804 } 2805 // fold (or c1, c2) -> c1|c2 2806 if (N0C && N1C) 2807 return DAG.FoldConstantArithmetic(ISD::OR, VT, N0C, N1C); 2808 // canonicalize constant to RHS 2809 if (N0C && !N1C) 2810 return DAG.getNode(ISD::OR, N->getDebugLoc(), VT, N1, N0); 2811 // fold (or x, 0) -> x 2812 if (N1C && N1C->isNullValue()) 2813 return N0; 2814 // fold (or x, -1) -> -1 2815 if (N1C && N1C->isAllOnesValue()) 2816 return N1; 2817 // fold (or x, c) -> c iff (x & ~c) == 0 2818 if (N1C && DAG.MaskedValueIsZero(N0, ~N1C->getAPIntValue())) 2819 return N1; 2820 2821 // Recognize halfword bswaps as (bswap + rotl 16) or (bswap + shl 16) 2822 SDValue BSwap = MatchBSwapHWord(N, N0, N1); 2823 if (BSwap.getNode() != 0) 2824 return BSwap; 2825 BSwap = MatchBSwapHWordLow(N, N0, N1); 2826 if (BSwap.getNode() != 0) 2827 return BSwap; 2828 2829 // reassociate or 2830 SDValue ROR = ReassociateOps(ISD::OR, N->getDebugLoc(), N0, N1); 2831 if (ROR.getNode() != 0) 2832 return ROR; 2833 // Canonicalize (or (and X, c1), c2) -> (and (or X, c2), c1|c2) 2834 // iff (c1 & c2) == 0. 2835 if (N1C && N0.getOpcode() == ISD::AND && N0.getNode()->hasOneUse() && 2836 isa<ConstantSDNode>(N0.getOperand(1))) { 2837 ConstantSDNode *C1 = cast<ConstantSDNode>(N0.getOperand(1)); 2838 if ((C1->getAPIntValue() & N1C->getAPIntValue()) != 0) 2839 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, 2840 DAG.getNode(ISD::OR, N0.getDebugLoc(), VT, 2841 N0.getOperand(0), N1), 2842 DAG.FoldConstantArithmetic(ISD::OR, VT, N1C, C1)); 2843 } 2844 // fold (or (setcc x), (setcc y)) -> (setcc (or x, y)) 2845 if (isSetCCEquivalent(N0, LL, LR, CC0) && isSetCCEquivalent(N1, RL, RR, CC1)){ 2846 ISD::CondCode Op0 = cast<CondCodeSDNode>(CC0)->get(); 2847 ISD::CondCode Op1 = cast<CondCodeSDNode>(CC1)->get(); 2848 2849 if (LR == RR && isa<ConstantSDNode>(LR) && Op0 == Op1 && 2850 LL.getValueType().isInteger()) { 2851 // fold (or (setne X, 0), (setne Y, 0)) -> (setne (or X, Y), 0) 2852 // fold (or (setlt X, 0), (setlt Y, 0)) -> (setne (or X, Y), 0) 2853 if (cast<ConstantSDNode>(LR)->isNullValue() && 2854 (Op1 == ISD::SETNE || Op1 == ISD::SETLT)) { 2855 SDValue ORNode = DAG.getNode(ISD::OR, LR.getDebugLoc(), 2856 LR.getValueType(), LL, RL); 2857 AddToWorkList(ORNode.getNode()); 2858 return DAG.getSetCC(N->getDebugLoc(), VT, ORNode, LR, Op1); 2859 } 2860 // fold (or (setne X, -1), (setne Y, -1)) -> (setne (and X, Y), -1) 2861 // fold (or (setgt X, -1), (setgt Y -1)) -> (setgt (and X, Y), -1) 2862 if (cast<ConstantSDNode>(LR)->isAllOnesValue() && 2863 (Op1 == ISD::SETNE || Op1 == ISD::SETGT)) { 2864 SDValue ANDNode = DAG.getNode(ISD::AND, LR.getDebugLoc(), 2865 LR.getValueType(), LL, RL); 2866 AddToWorkList(ANDNode.getNode()); 2867 return DAG.getSetCC(N->getDebugLoc(), VT, ANDNode, LR, Op1); 2868 } 2869 } 2870 // canonicalize equivalent to ll == rl 2871 if (LL == RR && LR == RL) { 2872 Op1 = ISD::getSetCCSwappedOperands(Op1); 2873 std::swap(RL, RR); 2874 } 2875 if (LL == RL && LR == RR) { 2876 bool isInteger = LL.getValueType().isInteger(); 2877 ISD::CondCode Result = ISD::getSetCCOrOperation(Op0, Op1, isInteger); 2878 if (Result != ISD::SETCC_INVALID && 2879 (!LegalOperations || TLI.isCondCodeLegal(Result, LL.getValueType()))) 2880 return DAG.getSetCC(N->getDebugLoc(), N0.getValueType(), 2881 LL, LR, Result); 2882 } 2883 } 2884 2885 // Simplify: (or (op x...), (op y...)) -> (op (or x, y)) 2886 if (N0.getOpcode() == N1.getOpcode()) { 2887 SDValue Tmp = SimplifyBinOpWithSameOpcodeHands(N); 2888 if (Tmp.getNode()) return Tmp; 2889 } 2890 2891 // (or (and X, C1), (and Y, C2)) -> (and (or X, Y), C3) if possible. 2892 if (N0.getOpcode() == ISD::AND && 2893 N1.getOpcode() == ISD::AND && 2894 N0.getOperand(1).getOpcode() == ISD::Constant && 2895 N1.getOperand(1).getOpcode() == ISD::Constant && 2896 // Don't increase # computations. 2897 (N0.getNode()->hasOneUse() || N1.getNode()->hasOneUse())) { 2898 // We can only do this xform if we know that bits from X that are set in C2 2899 // but not in C1 are already zero. Likewise for Y. 2900 const APInt &LHSMask = 2901 cast<ConstantSDNode>(N0.getOperand(1))->getAPIntValue(); 2902 const APInt &RHSMask = 2903 cast<ConstantSDNode>(N1.getOperand(1))->getAPIntValue(); 2904 2905 if (DAG.MaskedValueIsZero(N0.getOperand(0), RHSMask&~LHSMask) && 2906 DAG.MaskedValueIsZero(N1.getOperand(0), LHSMask&~RHSMask)) { 2907 SDValue X = DAG.getNode(ISD::OR, N0.getDebugLoc(), VT, 2908 N0.getOperand(0), N1.getOperand(0)); 2909 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, X, 2910 DAG.getConstant(LHSMask | RHSMask, VT)); 2911 } 2912 } 2913 2914 // See if this is some rotate idiom. 2915 if (SDNode *Rot = MatchRotate(N0, N1, N->getDebugLoc())) 2916 return SDValue(Rot, 0); 2917 2918 // Simplify the operands using demanded-bits information. 2919 if (!VT.isVector() && 2920 SimplifyDemandedBits(SDValue(N, 0))) 2921 return SDValue(N, 0); 2922 2923 return SDValue(); 2924} 2925 2926/// MatchRotateHalf - Match "(X shl/srl V1) & V2" where V2 may not be present. 2927static bool MatchRotateHalf(SDValue Op, SDValue &Shift, SDValue &Mask) { 2928 if (Op.getOpcode() == ISD::AND) { 2929 if (isa<ConstantSDNode>(Op.getOperand(1))) { 2930 Mask = Op.getOperand(1); 2931 Op = Op.getOperand(0); 2932 } else { 2933 return false; 2934 } 2935 } 2936 2937 if (Op.getOpcode() == ISD::SRL || Op.getOpcode() == ISD::SHL) { 2938 Shift = Op; 2939 return true; 2940 } 2941 2942 return false; 2943} 2944 2945// MatchRotate - Handle an 'or' of two operands. If this is one of the many 2946// idioms for rotate, and if the target supports rotation instructions, generate 2947// a rot[lr]. 2948SDNode *DAGCombiner::MatchRotate(SDValue LHS, SDValue RHS, DebugLoc DL) { 2949 // Must be a legal type. Expanded 'n promoted things won't work with rotates. 2950 EVT VT = LHS.getValueType(); 2951 if (!TLI.isTypeLegal(VT)) return 0; 2952 2953 // The target must have at least one rotate flavor. 2954 bool HasROTL = TLI.isOperationLegalOrCustom(ISD::ROTL, VT); 2955 bool HasROTR = TLI.isOperationLegalOrCustom(ISD::ROTR, VT); 2956 if (!HasROTL && !HasROTR) return 0; 2957 2958 // Match "(X shl/srl V1) & V2" where V2 may not be present. 2959 SDValue LHSShift; // The shift. 2960 SDValue LHSMask; // AND value if any. 2961 if (!MatchRotateHalf(LHS, LHSShift, LHSMask)) 2962 return 0; // Not part of a rotate. 2963 2964 SDValue RHSShift; // The shift. 2965 SDValue RHSMask; // AND value if any. 2966 if (!MatchRotateHalf(RHS, RHSShift, RHSMask)) 2967 return 0; // Not part of a rotate. 2968 2969 if (LHSShift.getOperand(0) != RHSShift.getOperand(0)) 2970 return 0; // Not shifting the same value. 2971 2972 if (LHSShift.getOpcode() == RHSShift.getOpcode()) 2973 return 0; // Shifts must disagree. 2974 2975 // Canonicalize shl to left side in a shl/srl pair. 2976 if (RHSShift.getOpcode() == ISD::SHL) { 2977 std::swap(LHS, RHS); 2978 std::swap(LHSShift, RHSShift); 2979 std::swap(LHSMask , RHSMask ); 2980 } 2981 2982 unsigned OpSizeInBits = VT.getSizeInBits(); 2983 SDValue LHSShiftArg = LHSShift.getOperand(0); 2984 SDValue LHSShiftAmt = LHSShift.getOperand(1); 2985 SDValue RHSShiftAmt = RHSShift.getOperand(1); 2986 2987 // fold (or (shl x, C1), (srl x, C2)) -> (rotl x, C1) 2988 // fold (or (shl x, C1), (srl x, C2)) -> (rotr x, C2) 2989 if (LHSShiftAmt.getOpcode() == ISD::Constant && 2990 RHSShiftAmt.getOpcode() == ISD::Constant) { 2991 uint64_t LShVal = cast<ConstantSDNode>(LHSShiftAmt)->getZExtValue(); 2992 uint64_t RShVal = cast<ConstantSDNode>(RHSShiftAmt)->getZExtValue(); 2993 if ((LShVal + RShVal) != OpSizeInBits) 2994 return 0; 2995 2996 SDValue Rot; 2997 if (HasROTL) 2998 Rot = DAG.getNode(ISD::ROTL, DL, VT, LHSShiftArg, LHSShiftAmt); 2999 else 3000 Rot = DAG.getNode(ISD::ROTR, DL, VT, LHSShiftArg, RHSShiftAmt); 3001 3002 // If there is an AND of either shifted operand, apply it to the result. 3003 if (LHSMask.getNode() || RHSMask.getNode()) { 3004 APInt Mask = APInt::getAllOnesValue(OpSizeInBits); 3005 3006 if (LHSMask.getNode()) { 3007 APInt RHSBits = APInt::getLowBitsSet(OpSizeInBits, LShVal); 3008 Mask &= cast<ConstantSDNode>(LHSMask)->getAPIntValue() | RHSBits; 3009 } 3010 if (RHSMask.getNode()) { 3011 APInt LHSBits = APInt::getHighBitsSet(OpSizeInBits, RShVal); 3012 Mask &= cast<ConstantSDNode>(RHSMask)->getAPIntValue() | LHSBits; 3013 } 3014 3015 Rot = DAG.getNode(ISD::AND, DL, VT, Rot, DAG.getConstant(Mask, VT)); 3016 } 3017 3018 return Rot.getNode(); 3019 } 3020 3021 // If there is a mask here, and we have a variable shift, we can't be sure 3022 // that we're masking out the right stuff. 3023 if (LHSMask.getNode() || RHSMask.getNode()) 3024 return 0; 3025 3026 // fold (or (shl x, y), (srl x, (sub 32, y))) -> (rotl x, y) 3027 // fold (or (shl x, y), (srl x, (sub 32, y))) -> (rotr x, (sub 32, y)) 3028 if (RHSShiftAmt.getOpcode() == ISD::SUB && 3029 LHSShiftAmt == RHSShiftAmt.getOperand(1)) { 3030 if (ConstantSDNode *SUBC = 3031 dyn_cast<ConstantSDNode>(RHSShiftAmt.getOperand(0))) { 3032 if (SUBC->getAPIntValue() == OpSizeInBits) { 3033 if (HasROTL) 3034 return DAG.getNode(ISD::ROTL, DL, VT, 3035 LHSShiftArg, LHSShiftAmt).getNode(); 3036 else 3037 return DAG.getNode(ISD::ROTR, DL, VT, 3038 LHSShiftArg, RHSShiftAmt).getNode(); 3039 } 3040 } 3041 } 3042 3043 // fold (or (shl x, (sub 32, y)), (srl x, r)) -> (rotr x, y) 3044 // fold (or (shl x, (sub 32, y)), (srl x, r)) -> (rotl x, (sub 32, y)) 3045 if (LHSShiftAmt.getOpcode() == ISD::SUB && 3046 RHSShiftAmt == LHSShiftAmt.getOperand(1)) { 3047 if (ConstantSDNode *SUBC = 3048 dyn_cast<ConstantSDNode>(LHSShiftAmt.getOperand(0))) { 3049 if (SUBC->getAPIntValue() == OpSizeInBits) { 3050 if (HasROTR) 3051 return DAG.getNode(ISD::ROTR, DL, VT, 3052 LHSShiftArg, RHSShiftAmt).getNode(); 3053 else 3054 return DAG.getNode(ISD::ROTL, DL, VT, 3055 LHSShiftArg, LHSShiftAmt).getNode(); 3056 } 3057 } 3058 } 3059 3060 // Look for sign/zext/any-extended or truncate cases: 3061 if ((LHSShiftAmt.getOpcode() == ISD::SIGN_EXTEND 3062 || LHSShiftAmt.getOpcode() == ISD::ZERO_EXTEND 3063 || LHSShiftAmt.getOpcode() == ISD::ANY_EXTEND 3064 || LHSShiftAmt.getOpcode() == ISD::TRUNCATE) && 3065 (RHSShiftAmt.getOpcode() == ISD::SIGN_EXTEND 3066 || RHSShiftAmt.getOpcode() == ISD::ZERO_EXTEND 3067 || RHSShiftAmt.getOpcode() == ISD::ANY_EXTEND 3068 || RHSShiftAmt.getOpcode() == ISD::TRUNCATE)) { 3069 SDValue LExtOp0 = LHSShiftAmt.getOperand(0); 3070 SDValue RExtOp0 = RHSShiftAmt.getOperand(0); 3071 if (RExtOp0.getOpcode() == ISD::SUB && 3072 RExtOp0.getOperand(1) == LExtOp0) { 3073 // fold (or (shl x, (*ext y)), (srl x, (*ext (sub 32, y)))) -> 3074 // (rotl x, y) 3075 // fold (or (shl x, (*ext y)), (srl x, (*ext (sub 32, y)))) -> 3076 // (rotr x, (sub 32, y)) 3077 if (ConstantSDNode *SUBC = 3078 dyn_cast<ConstantSDNode>(RExtOp0.getOperand(0))) { 3079 if (SUBC->getAPIntValue() == OpSizeInBits) { 3080 return DAG.getNode(HasROTL ? ISD::ROTL : ISD::ROTR, DL, VT, 3081 LHSShiftArg, 3082 HasROTL ? LHSShiftAmt : RHSShiftAmt).getNode(); 3083 } 3084 } 3085 } else if (LExtOp0.getOpcode() == ISD::SUB && 3086 RExtOp0 == LExtOp0.getOperand(1)) { 3087 // fold (or (shl x, (*ext (sub 32, y))), (srl x, (*ext y))) -> 3088 // (rotr x, y) 3089 // fold (or (shl x, (*ext (sub 32, y))), (srl x, (*ext y))) -> 3090 // (rotl x, (sub 32, y)) 3091 if (ConstantSDNode *SUBC = 3092 dyn_cast<ConstantSDNode>(LExtOp0.getOperand(0))) { 3093 if (SUBC->getAPIntValue() == OpSizeInBits) { 3094 return DAG.getNode(HasROTR ? ISD::ROTR : ISD::ROTL, DL, VT, 3095 LHSShiftArg, 3096 HasROTR ? RHSShiftAmt : LHSShiftAmt).getNode(); 3097 } 3098 } 3099 } 3100 } 3101 3102 return 0; 3103} 3104 3105SDValue DAGCombiner::visitXOR(SDNode *N) { 3106 SDValue N0 = N->getOperand(0); 3107 SDValue N1 = N->getOperand(1); 3108 SDValue LHS, RHS, CC; 3109 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 3110 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 3111 EVT VT = N0.getValueType(); 3112 3113 // fold vector ops 3114 if (VT.isVector()) { 3115 SDValue FoldedVOp = SimplifyVBinOp(N); 3116 if (FoldedVOp.getNode()) return FoldedVOp; 3117 } 3118 3119 // fold (xor undef, undef) -> 0. This is a common idiom (misuse). 3120 if (N0.getOpcode() == ISD::UNDEF && N1.getOpcode() == ISD::UNDEF) 3121 return DAG.getConstant(0, VT); 3122 // fold (xor x, undef) -> undef 3123 if (N0.getOpcode() == ISD::UNDEF) 3124 return N0; 3125 if (N1.getOpcode() == ISD::UNDEF) 3126 return N1; 3127 // fold (xor c1, c2) -> c1^c2 3128 if (N0C && N1C) 3129 return DAG.FoldConstantArithmetic(ISD::XOR, VT, N0C, N1C); 3130 // canonicalize constant to RHS 3131 if (N0C && !N1C) 3132 return DAG.getNode(ISD::XOR, N->getDebugLoc(), VT, N1, N0); 3133 // fold (xor x, 0) -> x 3134 if (N1C && N1C->isNullValue()) 3135 return N0; 3136 // reassociate xor 3137 SDValue RXOR = ReassociateOps(ISD::XOR, N->getDebugLoc(), N0, N1); 3138 if (RXOR.getNode() != 0) 3139 return RXOR; 3140 3141 // fold !(x cc y) -> (x !cc y) 3142 if (N1C && N1C->getAPIntValue() == 1 && isSetCCEquivalent(N0, LHS, RHS, CC)) { 3143 bool isInt = LHS.getValueType().isInteger(); 3144 ISD::CondCode NotCC = ISD::getSetCCInverse(cast<CondCodeSDNode>(CC)->get(), 3145 isInt); 3146 3147 if (!LegalOperations || TLI.isCondCodeLegal(NotCC, LHS.getValueType())) { 3148 switch (N0.getOpcode()) { 3149 default: 3150 llvm_unreachable("Unhandled SetCC Equivalent!"); 3151 case ISD::SETCC: 3152 return DAG.getSetCC(N->getDebugLoc(), VT, LHS, RHS, NotCC); 3153 case ISD::SELECT_CC: 3154 return DAG.getSelectCC(N->getDebugLoc(), LHS, RHS, N0.getOperand(2), 3155 N0.getOperand(3), NotCC); 3156 } 3157 } 3158 } 3159 3160 // fold (not (zext (setcc x, y))) -> (zext (not (setcc x, y))) 3161 if (N1C && N1C->getAPIntValue() == 1 && N0.getOpcode() == ISD::ZERO_EXTEND && 3162 N0.getNode()->hasOneUse() && 3163 isSetCCEquivalent(N0.getOperand(0), LHS, RHS, CC)){ 3164 SDValue V = N0.getOperand(0); 3165 V = DAG.getNode(ISD::XOR, N0.getDebugLoc(), V.getValueType(), V, 3166 DAG.getConstant(1, V.getValueType())); 3167 AddToWorkList(V.getNode()); 3168 return DAG.getNode(ISD::ZERO_EXTEND, N->getDebugLoc(), VT, V); 3169 } 3170 3171 // fold (not (or x, y)) -> (and (not x), (not y)) iff x or y are setcc 3172 if (N1C && N1C->getAPIntValue() == 1 && VT == MVT::i1 && 3173 (N0.getOpcode() == ISD::OR || N0.getOpcode() == ISD::AND)) { 3174 SDValue LHS = N0.getOperand(0), RHS = N0.getOperand(1); 3175 if (isOneUseSetCC(RHS) || isOneUseSetCC(LHS)) { 3176 unsigned NewOpcode = N0.getOpcode() == ISD::AND ? ISD::OR : ISD::AND; 3177 LHS = DAG.getNode(ISD::XOR, LHS.getDebugLoc(), VT, LHS, N1); // LHS = ~LHS 3178 RHS = DAG.getNode(ISD::XOR, RHS.getDebugLoc(), VT, RHS, N1); // RHS = ~RHS 3179 AddToWorkList(LHS.getNode()); AddToWorkList(RHS.getNode()); 3180 return DAG.getNode(NewOpcode, N->getDebugLoc(), VT, LHS, RHS); 3181 } 3182 } 3183 // fold (not (or x, y)) -> (and (not x), (not y)) iff x or y are constants 3184 if (N1C && N1C->isAllOnesValue() && 3185 (N0.getOpcode() == ISD::OR || N0.getOpcode() == ISD::AND)) { 3186 SDValue LHS = N0.getOperand(0), RHS = N0.getOperand(1); 3187 if (isa<ConstantSDNode>(RHS) || isa<ConstantSDNode>(LHS)) { 3188 unsigned NewOpcode = N0.getOpcode() == ISD::AND ? ISD::OR : ISD::AND; 3189 LHS = DAG.getNode(ISD::XOR, LHS.getDebugLoc(), VT, LHS, N1); // LHS = ~LHS 3190 RHS = DAG.getNode(ISD::XOR, RHS.getDebugLoc(), VT, RHS, N1); // RHS = ~RHS 3191 AddToWorkList(LHS.getNode()); AddToWorkList(RHS.getNode()); 3192 return DAG.getNode(NewOpcode, N->getDebugLoc(), VT, LHS, RHS); 3193 } 3194 } 3195 // fold (xor (xor x, c1), c2) -> (xor x, (xor c1, c2)) 3196 if (N1C && N0.getOpcode() == ISD::XOR) { 3197 ConstantSDNode *N00C = dyn_cast<ConstantSDNode>(N0.getOperand(0)); 3198 ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N0.getOperand(1)); 3199 if (N00C) 3200 return DAG.getNode(ISD::XOR, N->getDebugLoc(), VT, N0.getOperand(1), 3201 DAG.getConstant(N1C->getAPIntValue() ^ 3202 N00C->getAPIntValue(), VT)); 3203 if (N01C) 3204 return DAG.getNode(ISD::XOR, N->getDebugLoc(), VT, N0.getOperand(0), 3205 DAG.getConstant(N1C->getAPIntValue() ^ 3206 N01C->getAPIntValue(), VT)); 3207 } 3208 // fold (xor x, x) -> 0 3209 if (N0 == N1) 3210 return tryFoldToZero(N->getDebugLoc(), TLI, VT, DAG, LegalOperations); 3211 3212 // Simplify: xor (op x...), (op y...) -> (op (xor x, y)) 3213 if (N0.getOpcode() == N1.getOpcode()) { 3214 SDValue Tmp = SimplifyBinOpWithSameOpcodeHands(N); 3215 if (Tmp.getNode()) return Tmp; 3216 } 3217 3218 // Simplify the expression using non-local knowledge. 3219 if (!VT.isVector() && 3220 SimplifyDemandedBits(SDValue(N, 0))) 3221 return SDValue(N, 0); 3222 3223 return SDValue(); 3224} 3225 3226/// visitShiftByConstant - Handle transforms common to the three shifts, when 3227/// the shift amount is a constant. 3228SDValue DAGCombiner::visitShiftByConstant(SDNode *N, unsigned Amt) { 3229 SDNode *LHS = N->getOperand(0).getNode(); 3230 if (!LHS->hasOneUse()) return SDValue(); 3231 3232 // We want to pull some binops through shifts, so that we have (and (shift)) 3233 // instead of (shift (and)), likewise for add, or, xor, etc. This sort of 3234 // thing happens with address calculations, so it's important to canonicalize 3235 // it. 3236 bool HighBitSet = false; // Can we transform this if the high bit is set? 3237 3238 switch (LHS->getOpcode()) { 3239 default: return SDValue(); 3240 case ISD::OR: 3241 case ISD::XOR: 3242 HighBitSet = false; // We can only transform sra if the high bit is clear. 3243 break; 3244 case ISD::AND: 3245 HighBitSet = true; // We can only transform sra if the high bit is set. 3246 break; 3247 case ISD::ADD: 3248 if (N->getOpcode() != ISD::SHL) 3249 return SDValue(); // only shl(add) not sr[al](add). 3250 HighBitSet = false; // We can only transform sra if the high bit is clear. 3251 break; 3252 } 3253 3254 // We require the RHS of the binop to be a constant as well. 3255 ConstantSDNode *BinOpCst = dyn_cast<ConstantSDNode>(LHS->getOperand(1)); 3256 if (!BinOpCst) return SDValue(); 3257 3258 // FIXME: disable this unless the input to the binop is a shift by a constant. 3259 // If it is not a shift, it pessimizes some common cases like: 3260 // 3261 // void foo(int *X, int i) { X[i & 1235] = 1; } 3262 // int bar(int *X, int i) { return X[i & 255]; } 3263 SDNode *BinOpLHSVal = LHS->getOperand(0).getNode(); 3264 if ((BinOpLHSVal->getOpcode() != ISD::SHL && 3265 BinOpLHSVal->getOpcode() != ISD::SRA && 3266 BinOpLHSVal->getOpcode() != ISD::SRL) || 3267 !isa<ConstantSDNode>(BinOpLHSVal->getOperand(1))) 3268 return SDValue(); 3269 3270 EVT VT = N->getValueType(0); 3271 3272 // If this is a signed shift right, and the high bit is modified by the 3273 // logical operation, do not perform the transformation. The highBitSet 3274 // boolean indicates the value of the high bit of the constant which would 3275 // cause it to be modified for this operation. 3276 if (N->getOpcode() == ISD::SRA) { 3277 bool BinOpRHSSignSet = BinOpCst->getAPIntValue().isNegative(); 3278 if (BinOpRHSSignSet != HighBitSet) 3279 return SDValue(); 3280 } 3281 3282 // Fold the constants, shifting the binop RHS by the shift amount. 3283 SDValue NewRHS = DAG.getNode(N->getOpcode(), LHS->getOperand(1).getDebugLoc(), 3284 N->getValueType(0), 3285 LHS->getOperand(1), N->getOperand(1)); 3286 3287 // Create the new shift. 3288 SDValue NewShift = DAG.getNode(N->getOpcode(), 3289 LHS->getOperand(0).getDebugLoc(), 3290 VT, LHS->getOperand(0), N->getOperand(1)); 3291 3292 // Create the new binop. 3293 return DAG.getNode(LHS->getOpcode(), N->getDebugLoc(), VT, NewShift, NewRHS); 3294} 3295 3296SDValue DAGCombiner::visitSHL(SDNode *N) { 3297 SDValue N0 = N->getOperand(0); 3298 SDValue N1 = N->getOperand(1); 3299 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 3300 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 3301 EVT VT = N0.getValueType(); 3302 unsigned OpSizeInBits = VT.getScalarType().getSizeInBits(); 3303 3304 // fold (shl c1, c2) -> c1<<c2 3305 if (N0C && N1C) 3306 return DAG.FoldConstantArithmetic(ISD::SHL, VT, N0C, N1C); 3307 // fold (shl 0, x) -> 0 3308 if (N0C && N0C->isNullValue()) 3309 return N0; 3310 // fold (shl x, c >= size(x)) -> undef 3311 if (N1C && N1C->getZExtValue() >= OpSizeInBits) 3312 return DAG.getUNDEF(VT); 3313 // fold (shl x, 0) -> x 3314 if (N1C && N1C->isNullValue()) 3315 return N0; 3316 // fold (shl undef, x) -> 0 3317 if (N0.getOpcode() == ISD::UNDEF) 3318 return DAG.getConstant(0, VT); 3319 // if (shl x, c) is known to be zero, return 0 3320 if (DAG.MaskedValueIsZero(SDValue(N, 0), 3321 APInt::getAllOnesValue(OpSizeInBits))) 3322 return DAG.getConstant(0, VT); 3323 // fold (shl x, (trunc (and y, c))) -> (shl x, (and (trunc y), (trunc c))). 3324 if (N1.getOpcode() == ISD::TRUNCATE && 3325 N1.getOperand(0).getOpcode() == ISD::AND && 3326 N1.hasOneUse() && N1.getOperand(0).hasOneUse()) { 3327 SDValue N101 = N1.getOperand(0).getOperand(1); 3328 if (ConstantSDNode *N101C = dyn_cast<ConstantSDNode>(N101)) { 3329 EVT TruncVT = N1.getValueType(); 3330 SDValue N100 = N1.getOperand(0).getOperand(0); 3331 APInt TruncC = N101C->getAPIntValue(); 3332 TruncC = TruncC.trunc(TruncVT.getSizeInBits()); 3333 return DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, N0, 3334 DAG.getNode(ISD::AND, N->getDebugLoc(), TruncVT, 3335 DAG.getNode(ISD::TRUNCATE, 3336 N->getDebugLoc(), 3337 TruncVT, N100), 3338 DAG.getConstant(TruncC, TruncVT))); 3339 } 3340 } 3341 3342 if (N1C && SimplifyDemandedBits(SDValue(N, 0))) 3343 return SDValue(N, 0); 3344 3345 // fold (shl (shl x, c1), c2) -> 0 or (shl x, (add c1, c2)) 3346 if (N1C && N0.getOpcode() == ISD::SHL && 3347 N0.getOperand(1).getOpcode() == ISD::Constant) { 3348 uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getZExtValue(); 3349 uint64_t c2 = N1C->getZExtValue(); 3350 if (c1 + c2 >= OpSizeInBits) 3351 return DAG.getConstant(0, VT); 3352 return DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, N0.getOperand(0), 3353 DAG.getConstant(c1 + c2, N1.getValueType())); 3354 } 3355 3356 // fold (shl (ext (shl x, c1)), c2) -> (ext (shl x, (add c1, c2))) 3357 // For this to be valid, the second form must not preserve any of the bits 3358 // that are shifted out by the inner shift in the first form. This means 3359 // the outer shift size must be >= the number of bits added by the ext. 3360 // As a corollary, we don't care what kind of ext it is. 3361 if (N1C && (N0.getOpcode() == ISD::ZERO_EXTEND || 3362 N0.getOpcode() == ISD::ANY_EXTEND || 3363 N0.getOpcode() == ISD::SIGN_EXTEND) && 3364 N0.getOperand(0).getOpcode() == ISD::SHL && 3365 isa<ConstantSDNode>(N0.getOperand(0)->getOperand(1))) { 3366 uint64_t c1 = 3367 cast<ConstantSDNode>(N0.getOperand(0)->getOperand(1))->getZExtValue(); 3368 uint64_t c2 = N1C->getZExtValue(); 3369 EVT InnerShiftVT = N0.getOperand(0).getValueType(); 3370 uint64_t InnerShiftSize = InnerShiftVT.getScalarType().getSizeInBits(); 3371 if (c2 >= OpSizeInBits - InnerShiftSize) { 3372 if (c1 + c2 >= OpSizeInBits) 3373 return DAG.getConstant(0, VT); 3374 return DAG.getNode(ISD::SHL, N0->getDebugLoc(), VT, 3375 DAG.getNode(N0.getOpcode(), N0->getDebugLoc(), VT, 3376 N0.getOperand(0)->getOperand(0)), 3377 DAG.getConstant(c1 + c2, N1.getValueType())); 3378 } 3379 } 3380 3381 // fold (shl (srl x, c1), c2) -> (and (shl x, (sub c2, c1), MASK) or 3382 // (and (srl x, (sub c1, c2), MASK) 3383 // Only fold this if the inner shift has no other uses -- if it does, folding 3384 // this will increase the total number of instructions. 3385 if (N1C && N0.getOpcode() == ISD::SRL && N0.hasOneUse() && 3386 N0.getOperand(1).getOpcode() == ISD::Constant) { 3387 uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getZExtValue(); 3388 if (c1 < VT.getSizeInBits()) { 3389 uint64_t c2 = N1C->getZExtValue(); 3390 APInt Mask = APInt::getHighBitsSet(VT.getSizeInBits(), 3391 VT.getSizeInBits() - c1); 3392 SDValue Shift; 3393 if (c2 > c1) { 3394 Mask = Mask.shl(c2-c1); 3395 Shift = DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, N0.getOperand(0), 3396 DAG.getConstant(c2-c1, N1.getValueType())); 3397 } else { 3398 Mask = Mask.lshr(c1-c2); 3399 Shift = DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, N0.getOperand(0), 3400 DAG.getConstant(c1-c2, N1.getValueType())); 3401 } 3402 return DAG.getNode(ISD::AND, N0.getDebugLoc(), VT, Shift, 3403 DAG.getConstant(Mask, VT)); 3404 } 3405 } 3406 // fold (shl (sra x, c1), c1) -> (and x, (shl -1, c1)) 3407 if (N1C && N0.getOpcode() == ISD::SRA && N1 == N0.getOperand(1)) { 3408 SDValue HiBitsMask = 3409 DAG.getConstant(APInt::getHighBitsSet(VT.getSizeInBits(), 3410 VT.getSizeInBits() - 3411 N1C->getZExtValue()), 3412 VT); 3413 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, N0.getOperand(0), 3414 HiBitsMask); 3415 } 3416 3417 if (N1C) { 3418 SDValue NewSHL = visitShiftByConstant(N, N1C->getZExtValue()); 3419 if (NewSHL.getNode()) 3420 return NewSHL; 3421 } 3422 3423 return SDValue(); 3424} 3425 3426SDValue DAGCombiner::visitSRA(SDNode *N) { 3427 SDValue N0 = N->getOperand(0); 3428 SDValue N1 = N->getOperand(1); 3429 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 3430 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 3431 EVT VT = N0.getValueType(); 3432 unsigned OpSizeInBits = VT.getScalarType().getSizeInBits(); 3433 3434 // fold (sra c1, c2) -> (sra c1, c2) 3435 if (N0C && N1C) 3436 return DAG.FoldConstantArithmetic(ISD::SRA, VT, N0C, N1C); 3437 // fold (sra 0, x) -> 0 3438 if (N0C && N0C->isNullValue()) 3439 return N0; 3440 // fold (sra -1, x) -> -1 3441 if (N0C && N0C->isAllOnesValue()) 3442 return N0; 3443 // fold (sra x, (setge c, size(x))) -> undef 3444 if (N1C && N1C->getZExtValue() >= OpSizeInBits) 3445 return DAG.getUNDEF(VT); 3446 // fold (sra x, 0) -> x 3447 if (N1C && N1C->isNullValue()) 3448 return N0; 3449 // fold (sra (shl x, c1), c1) -> sext_inreg for some c1 and target supports 3450 // sext_inreg. 3451 if (N1C && N0.getOpcode() == ISD::SHL && N1 == N0.getOperand(1)) { 3452 unsigned LowBits = OpSizeInBits - (unsigned)N1C->getZExtValue(); 3453 EVT ExtVT = EVT::getIntegerVT(*DAG.getContext(), LowBits); 3454 if (VT.isVector()) 3455 ExtVT = EVT::getVectorVT(*DAG.getContext(), 3456 ExtVT, VT.getVectorNumElements()); 3457 if ((!LegalOperations || 3458 TLI.isOperationLegal(ISD::SIGN_EXTEND_INREG, ExtVT))) 3459 return DAG.getNode(ISD::SIGN_EXTEND_INREG, N->getDebugLoc(), VT, 3460 N0.getOperand(0), DAG.getValueType(ExtVT)); 3461 } 3462 3463 // fold (sra (sra x, c1), c2) -> (sra x, (add c1, c2)) 3464 if (N1C && N0.getOpcode() == ISD::SRA) { 3465 if (ConstantSDNode *C1 = dyn_cast<ConstantSDNode>(N0.getOperand(1))) { 3466 unsigned Sum = N1C->getZExtValue() + C1->getZExtValue(); 3467 if (Sum >= OpSizeInBits) Sum = OpSizeInBits-1; 3468 return DAG.getNode(ISD::SRA, N->getDebugLoc(), VT, N0.getOperand(0), 3469 DAG.getConstant(Sum, N1C->getValueType(0))); 3470 } 3471 } 3472 3473 // fold (sra (shl X, m), (sub result_size, n)) 3474 // -> (sign_extend (trunc (shl X, (sub (sub result_size, n), m)))) for 3475 // result_size - n != m. 3476 // If truncate is free for the target sext(shl) is likely to result in better 3477 // code. 3478 if (N0.getOpcode() == ISD::SHL) { 3479 // Get the two constanst of the shifts, CN0 = m, CN = n. 3480 const ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N0.getOperand(1)); 3481 if (N01C && N1C) { 3482 // Determine what the truncate's result bitsize and type would be. 3483 EVT TruncVT = 3484 EVT::getIntegerVT(*DAG.getContext(), 3485 OpSizeInBits - N1C->getZExtValue()); 3486 // Determine the residual right-shift amount. 3487 signed ShiftAmt = N1C->getZExtValue() - N01C->getZExtValue(); 3488 3489 // If the shift is not a no-op (in which case this should be just a sign 3490 // extend already), the truncated to type is legal, sign_extend is legal 3491 // on that type, and the truncate to that type is both legal and free, 3492 // perform the transform. 3493 if ((ShiftAmt > 0) && 3494 TLI.isOperationLegalOrCustom(ISD::SIGN_EXTEND, TruncVT) && 3495 TLI.isOperationLegalOrCustom(ISD::TRUNCATE, VT) && 3496 TLI.isTruncateFree(VT, TruncVT)) { 3497 3498 SDValue Amt = DAG.getConstant(ShiftAmt, 3499 getShiftAmountTy(N0.getOperand(0).getValueType())); 3500 SDValue Shift = DAG.getNode(ISD::SRL, N0.getDebugLoc(), VT, 3501 N0.getOperand(0), Amt); 3502 SDValue Trunc = DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(), TruncVT, 3503 Shift); 3504 return DAG.getNode(ISD::SIGN_EXTEND, N->getDebugLoc(), 3505 N->getValueType(0), Trunc); 3506 } 3507 } 3508 } 3509 3510 // fold (sra x, (trunc (and y, c))) -> (sra x, (and (trunc y), (trunc c))). 3511 if (N1.getOpcode() == ISD::TRUNCATE && 3512 N1.getOperand(0).getOpcode() == ISD::AND && 3513 N1.hasOneUse() && N1.getOperand(0).hasOneUse()) { 3514 SDValue N101 = N1.getOperand(0).getOperand(1); 3515 if (ConstantSDNode *N101C = dyn_cast<ConstantSDNode>(N101)) { 3516 EVT TruncVT = N1.getValueType(); 3517 SDValue N100 = N1.getOperand(0).getOperand(0); 3518 APInt TruncC = N101C->getAPIntValue(); 3519 TruncC = TruncC.trunc(TruncVT.getScalarType().getSizeInBits()); 3520 return DAG.getNode(ISD::SRA, N->getDebugLoc(), VT, N0, 3521 DAG.getNode(ISD::AND, N->getDebugLoc(), 3522 TruncVT, 3523 DAG.getNode(ISD::TRUNCATE, 3524 N->getDebugLoc(), 3525 TruncVT, N100), 3526 DAG.getConstant(TruncC, TruncVT))); 3527 } 3528 } 3529 3530 // fold (sra (trunc (sr x, c1)), c2) -> (trunc (sra x, c1+c2)) 3531 // if c1 is equal to the number of bits the trunc removes 3532 if (N0.getOpcode() == ISD::TRUNCATE && 3533 (N0.getOperand(0).getOpcode() == ISD::SRL || 3534 N0.getOperand(0).getOpcode() == ISD::SRA) && 3535 N0.getOperand(0).hasOneUse() && 3536 N0.getOperand(0).getOperand(1).hasOneUse() && 3537 N1C && isa<ConstantSDNode>(N0.getOperand(0).getOperand(1))) { 3538 EVT LargeVT = N0.getOperand(0).getValueType(); 3539 ConstantSDNode *LargeShiftAmt = 3540 cast<ConstantSDNode>(N0.getOperand(0).getOperand(1)); 3541 3542 if (LargeVT.getScalarType().getSizeInBits() - OpSizeInBits == 3543 LargeShiftAmt->getZExtValue()) { 3544 SDValue Amt = 3545 DAG.getConstant(LargeShiftAmt->getZExtValue() + N1C->getZExtValue(), 3546 getShiftAmountTy(N0.getOperand(0).getOperand(0).getValueType())); 3547 SDValue SRA = DAG.getNode(ISD::SRA, N->getDebugLoc(), LargeVT, 3548 N0.getOperand(0).getOperand(0), Amt); 3549 return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, SRA); 3550 } 3551 } 3552 3553 // Simplify, based on bits shifted out of the LHS. 3554 if (N1C && SimplifyDemandedBits(SDValue(N, 0))) 3555 return SDValue(N, 0); 3556 3557 3558 // If the sign bit is known to be zero, switch this to a SRL. 3559 if (DAG.SignBitIsZero(N0)) 3560 return DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, N0, N1); 3561 3562 if (N1C) { 3563 SDValue NewSRA = visitShiftByConstant(N, N1C->getZExtValue()); 3564 if (NewSRA.getNode()) 3565 return NewSRA; 3566 } 3567 3568 return SDValue(); 3569} 3570 3571SDValue DAGCombiner::visitSRL(SDNode *N) { 3572 SDValue N0 = N->getOperand(0); 3573 SDValue N1 = N->getOperand(1); 3574 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 3575 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 3576 EVT VT = N0.getValueType(); 3577 unsigned OpSizeInBits = VT.getScalarType().getSizeInBits(); 3578 3579 // fold (srl c1, c2) -> c1 >>u c2 3580 if (N0C && N1C) 3581 return DAG.FoldConstantArithmetic(ISD::SRL, VT, N0C, N1C); 3582 // fold (srl 0, x) -> 0 3583 if (N0C && N0C->isNullValue()) 3584 return N0; 3585 // fold (srl x, c >= size(x)) -> undef 3586 if (N1C && N1C->getZExtValue() >= OpSizeInBits) 3587 return DAG.getUNDEF(VT); 3588 // fold (srl x, 0) -> x 3589 if (N1C && N1C->isNullValue()) 3590 return N0; 3591 // if (srl x, c) is known to be zero, return 0 3592 if (N1C && DAG.MaskedValueIsZero(SDValue(N, 0), 3593 APInt::getAllOnesValue(OpSizeInBits))) 3594 return DAG.getConstant(0, VT); 3595 3596 // fold (srl (srl x, c1), c2) -> 0 or (srl x, (add c1, c2)) 3597 if (N1C && N0.getOpcode() == ISD::SRL && 3598 N0.getOperand(1).getOpcode() == ISD::Constant) { 3599 uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getZExtValue(); 3600 uint64_t c2 = N1C->getZExtValue(); 3601 if (c1 + c2 >= OpSizeInBits) 3602 return DAG.getConstant(0, VT); 3603 return DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, N0.getOperand(0), 3604 DAG.getConstant(c1 + c2, N1.getValueType())); 3605 } 3606 3607 // fold (srl (trunc (srl x, c1)), c2) -> 0 or (trunc (srl x, (add c1, c2))) 3608 if (N1C && N0.getOpcode() == ISD::TRUNCATE && 3609 N0.getOperand(0).getOpcode() == ISD::SRL && 3610 isa<ConstantSDNode>(N0.getOperand(0)->getOperand(1))) { 3611 uint64_t c1 = 3612 cast<ConstantSDNode>(N0.getOperand(0)->getOperand(1))->getZExtValue(); 3613 uint64_t c2 = N1C->getZExtValue(); 3614 EVT InnerShiftVT = N0.getOperand(0).getValueType(); 3615 EVT ShiftCountVT = N0.getOperand(0)->getOperand(1).getValueType(); 3616 uint64_t InnerShiftSize = InnerShiftVT.getScalarType().getSizeInBits(); 3617 // This is only valid if the OpSizeInBits + c1 = size of inner shift. 3618 if (c1 + OpSizeInBits == InnerShiftSize) { 3619 if (c1 + c2 >= InnerShiftSize) 3620 return DAG.getConstant(0, VT); 3621 return DAG.getNode(ISD::TRUNCATE, N0->getDebugLoc(), VT, 3622 DAG.getNode(ISD::SRL, N0->getDebugLoc(), InnerShiftVT, 3623 N0.getOperand(0)->getOperand(0), 3624 DAG.getConstant(c1 + c2, ShiftCountVT))); 3625 } 3626 } 3627 3628 // fold (srl (shl x, c), c) -> (and x, cst2) 3629 if (N1C && N0.getOpcode() == ISD::SHL && N0.getOperand(1) == N1 && 3630 N0.getValueSizeInBits() <= 64) { 3631 uint64_t ShAmt = N1C->getZExtValue()+64-N0.getValueSizeInBits(); 3632 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, N0.getOperand(0), 3633 DAG.getConstant(~0ULL >> ShAmt, VT)); 3634 } 3635 3636 3637 // fold (srl (anyextend x), c) -> (anyextend (srl x, c)) 3638 if (N1C && N0.getOpcode() == ISD::ANY_EXTEND) { 3639 // Shifting in all undef bits? 3640 EVT SmallVT = N0.getOperand(0).getValueType(); 3641 if (N1C->getZExtValue() >= SmallVT.getSizeInBits()) 3642 return DAG.getUNDEF(VT); 3643 3644 if (!LegalTypes || TLI.isTypeDesirableForOp(ISD::SRL, SmallVT)) { 3645 uint64_t ShiftAmt = N1C->getZExtValue(); 3646 SDValue SmallShift = DAG.getNode(ISD::SRL, N0.getDebugLoc(), SmallVT, 3647 N0.getOperand(0), 3648 DAG.getConstant(ShiftAmt, getShiftAmountTy(SmallVT))); 3649 AddToWorkList(SmallShift.getNode()); 3650 return DAG.getNode(ISD::ANY_EXTEND, N->getDebugLoc(), VT, SmallShift); 3651 } 3652 } 3653 3654 // fold (srl (sra X, Y), 31) -> (srl X, 31). This srl only looks at the sign 3655 // bit, which is unmodified by sra. 3656 if (N1C && N1C->getZExtValue() + 1 == VT.getSizeInBits()) { 3657 if (N0.getOpcode() == ISD::SRA) 3658 return DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, N0.getOperand(0), N1); 3659 } 3660 3661 // fold (srl (ctlz x), "5") -> x iff x has one bit set (the low bit). 3662 if (N1C && N0.getOpcode() == ISD::CTLZ && 3663 N1C->getAPIntValue() == Log2_32(VT.getSizeInBits())) { 3664 APInt KnownZero, KnownOne; 3665 APInt Mask = APInt::getAllOnesValue(VT.getScalarType().getSizeInBits()); 3666 DAG.ComputeMaskedBits(N0.getOperand(0), Mask, KnownZero, KnownOne); 3667 3668 // If any of the input bits are KnownOne, then the input couldn't be all 3669 // zeros, thus the result of the srl will always be zero. 3670 if (KnownOne.getBoolValue()) return DAG.getConstant(0, VT); 3671 3672 // If all of the bits input the to ctlz node are known to be zero, then 3673 // the result of the ctlz is "32" and the result of the shift is one. 3674 APInt UnknownBits = ~KnownZero & Mask; 3675 if (UnknownBits == 0) return DAG.getConstant(1, VT); 3676 3677 // Otherwise, check to see if there is exactly one bit input to the ctlz. 3678 if ((UnknownBits & (UnknownBits - 1)) == 0) { 3679 // Okay, we know that only that the single bit specified by UnknownBits 3680 // could be set on input to the CTLZ node. If this bit is set, the SRL 3681 // will return 0, if it is clear, it returns 1. Change the CTLZ/SRL pair 3682 // to an SRL/XOR pair, which is likely to simplify more. 3683 unsigned ShAmt = UnknownBits.countTrailingZeros(); 3684 SDValue Op = N0.getOperand(0); 3685 3686 if (ShAmt) { 3687 Op = DAG.getNode(ISD::SRL, N0.getDebugLoc(), VT, Op, 3688 DAG.getConstant(ShAmt, getShiftAmountTy(Op.getValueType()))); 3689 AddToWorkList(Op.getNode()); 3690 } 3691 3692 return DAG.getNode(ISD::XOR, N->getDebugLoc(), VT, 3693 Op, DAG.getConstant(1, VT)); 3694 } 3695 } 3696 3697 // fold (srl x, (trunc (and y, c))) -> (srl x, (and (trunc y), (trunc c))). 3698 if (N1.getOpcode() == ISD::TRUNCATE && 3699 N1.getOperand(0).getOpcode() == ISD::AND && 3700 N1.hasOneUse() && N1.getOperand(0).hasOneUse()) { 3701 SDValue N101 = N1.getOperand(0).getOperand(1); 3702 if (ConstantSDNode *N101C = dyn_cast<ConstantSDNode>(N101)) { 3703 EVT TruncVT = N1.getValueType(); 3704 SDValue N100 = N1.getOperand(0).getOperand(0); 3705 APInt TruncC = N101C->getAPIntValue(); 3706 TruncC = TruncC.trunc(TruncVT.getSizeInBits()); 3707 return DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, N0, 3708 DAG.getNode(ISD::AND, N->getDebugLoc(), 3709 TruncVT, 3710 DAG.getNode(ISD::TRUNCATE, 3711 N->getDebugLoc(), 3712 TruncVT, N100), 3713 DAG.getConstant(TruncC, TruncVT))); 3714 } 3715 } 3716 3717 // fold operands of srl based on knowledge that the low bits are not 3718 // demanded. 3719 if (N1C && SimplifyDemandedBits(SDValue(N, 0))) 3720 return SDValue(N, 0); 3721 3722 if (N1C) { 3723 SDValue NewSRL = visitShiftByConstant(N, N1C->getZExtValue()); 3724 if (NewSRL.getNode()) 3725 return NewSRL; 3726 } 3727 3728 // Attempt to convert a srl of a load into a narrower zero-extending load. 3729 SDValue NarrowLoad = ReduceLoadWidth(N); 3730 if (NarrowLoad.getNode()) 3731 return NarrowLoad; 3732 3733 // Here is a common situation. We want to optimize: 3734 // 3735 // %a = ... 3736 // %b = and i32 %a, 2 3737 // %c = srl i32 %b, 1 3738 // brcond i32 %c ... 3739 // 3740 // into 3741 // 3742 // %a = ... 3743 // %b = and %a, 2 3744 // %c = setcc eq %b, 0 3745 // brcond %c ... 3746 // 3747 // However when after the source operand of SRL is optimized into AND, the SRL 3748 // itself may not be optimized further. Look for it and add the BRCOND into 3749 // the worklist. 3750 if (N->hasOneUse()) { 3751 SDNode *Use = *N->use_begin(); 3752 if (Use->getOpcode() == ISD::BRCOND) 3753 AddToWorkList(Use); 3754 else if (Use->getOpcode() == ISD::TRUNCATE && Use->hasOneUse()) { 3755 // Also look pass the truncate. 3756 Use = *Use->use_begin(); 3757 if (Use->getOpcode() == ISD::BRCOND) 3758 AddToWorkList(Use); 3759 } 3760 } 3761 3762 return SDValue(); 3763} 3764 3765SDValue DAGCombiner::visitCTLZ(SDNode *N) { 3766 SDValue N0 = N->getOperand(0); 3767 EVT VT = N->getValueType(0); 3768 3769 // fold (ctlz c1) -> c2 3770 if (isa<ConstantSDNode>(N0)) 3771 return DAG.getNode(ISD::CTLZ, N->getDebugLoc(), VT, N0); 3772 return SDValue(); 3773} 3774 3775SDValue DAGCombiner::visitCTLZ_ZERO_UNDEF(SDNode *N) { 3776 SDValue N0 = N->getOperand(0); 3777 EVT VT = N->getValueType(0); 3778 3779 // fold (ctlz_zero_undef c1) -> c2 3780 if (isa<ConstantSDNode>(N0)) 3781 return DAG.getNode(ISD::CTLZ_ZERO_UNDEF, N->getDebugLoc(), VT, N0); 3782 return SDValue(); 3783} 3784 3785SDValue DAGCombiner::visitCTTZ(SDNode *N) { 3786 SDValue N0 = N->getOperand(0); 3787 EVT VT = N->getValueType(0); 3788 3789 // fold (cttz c1) -> c2 3790 if (isa<ConstantSDNode>(N0)) 3791 return DAG.getNode(ISD::CTTZ, N->getDebugLoc(), VT, N0); 3792 return SDValue(); 3793} 3794 3795SDValue DAGCombiner::visitCTTZ_ZERO_UNDEF(SDNode *N) { 3796 SDValue N0 = N->getOperand(0); 3797 EVT VT = N->getValueType(0); 3798 3799 // fold (cttz_zero_undef c1) -> c2 3800 if (isa<ConstantSDNode>(N0)) 3801 return DAG.getNode(ISD::CTTZ_ZERO_UNDEF, N->getDebugLoc(), VT, N0); 3802 return SDValue(); 3803} 3804 3805SDValue DAGCombiner::visitCTPOP(SDNode *N) { 3806 SDValue N0 = N->getOperand(0); 3807 EVT VT = N->getValueType(0); 3808 3809 // fold (ctpop c1) -> c2 3810 if (isa<ConstantSDNode>(N0)) 3811 return DAG.getNode(ISD::CTPOP, N->getDebugLoc(), VT, N0); 3812 return SDValue(); 3813} 3814 3815SDValue DAGCombiner::visitSELECT(SDNode *N) { 3816 SDValue N0 = N->getOperand(0); 3817 SDValue N1 = N->getOperand(1); 3818 SDValue N2 = N->getOperand(2); 3819 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 3820 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 3821 ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(N2); 3822 EVT VT = N->getValueType(0); 3823 EVT VT0 = N0.getValueType(); 3824 3825 // fold (select C, X, X) -> X 3826 if (N1 == N2) 3827 return N1; 3828 // fold (select true, X, Y) -> X 3829 if (N0C && !N0C->isNullValue()) 3830 return N1; 3831 // fold (select false, X, Y) -> Y 3832 if (N0C && N0C->isNullValue()) 3833 return N2; 3834 // fold (select C, 1, X) -> (or C, X) 3835 if (VT == MVT::i1 && N1C && N1C->getAPIntValue() == 1) 3836 return DAG.getNode(ISD::OR, N->getDebugLoc(), VT, N0, N2); 3837 // fold (select C, 0, 1) -> (xor C, 1) 3838 if (VT.isInteger() && 3839 (VT0 == MVT::i1 || 3840 (VT0.isInteger() && 3841 TLI.getBooleanContents(false) == TargetLowering::ZeroOrOneBooleanContent)) && 3842 N1C && N2C && N1C->isNullValue() && N2C->getAPIntValue() == 1) { 3843 SDValue XORNode; 3844 if (VT == VT0) 3845 return DAG.getNode(ISD::XOR, N->getDebugLoc(), VT0, 3846 N0, DAG.getConstant(1, VT0)); 3847 XORNode = DAG.getNode(ISD::XOR, N0.getDebugLoc(), VT0, 3848 N0, DAG.getConstant(1, VT0)); 3849 AddToWorkList(XORNode.getNode()); 3850 if (VT.bitsGT(VT0)) 3851 return DAG.getNode(ISD::ZERO_EXTEND, N->getDebugLoc(), VT, XORNode); 3852 return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, XORNode); 3853 } 3854 // fold (select C, 0, X) -> (and (not C), X) 3855 if (VT == VT0 && VT == MVT::i1 && N1C && N1C->isNullValue()) { 3856 SDValue NOTNode = DAG.getNOT(N0.getDebugLoc(), N0, VT); 3857 AddToWorkList(NOTNode.getNode()); 3858 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, NOTNode, N2); 3859 } 3860 // fold (select C, X, 1) -> (or (not C), X) 3861 if (VT == VT0 && VT == MVT::i1 && N2C && N2C->getAPIntValue() == 1) { 3862 SDValue NOTNode = DAG.getNOT(N0.getDebugLoc(), N0, VT); 3863 AddToWorkList(NOTNode.getNode()); 3864 return DAG.getNode(ISD::OR, N->getDebugLoc(), VT, NOTNode, N1); 3865 } 3866 // fold (select C, X, 0) -> (and C, X) 3867 if (VT == MVT::i1 && N2C && N2C->isNullValue()) 3868 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, N0, N1); 3869 // fold (select X, X, Y) -> (or X, Y) 3870 // fold (select X, 1, Y) -> (or X, Y) 3871 if (VT == MVT::i1 && (N0 == N1 || (N1C && N1C->getAPIntValue() == 1))) 3872 return DAG.getNode(ISD::OR, N->getDebugLoc(), VT, N0, N2); 3873 // fold (select X, Y, X) -> (and X, Y) 3874 // fold (select X, Y, 0) -> (and X, Y) 3875 if (VT == MVT::i1 && (N0 == N2 || (N2C && N2C->getAPIntValue() == 0))) 3876 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, N0, N1); 3877 3878 // If we can fold this based on the true/false value, do so. 3879 if (SimplifySelectOps(N, N1, N2)) 3880 return SDValue(N, 0); // Don't revisit N. 3881 3882 // fold selects based on a setcc into other things, such as min/max/abs 3883 if (N0.getOpcode() == ISD::SETCC) { 3884 // FIXME: 3885 // Check against MVT::Other for SELECT_CC, which is a workaround for targets 3886 // having to say they don't support SELECT_CC on every type the DAG knows 3887 // about, since there is no way to mark an opcode illegal at all value types 3888 if (TLI.isOperationLegalOrCustom(ISD::SELECT_CC, MVT::Other) && 3889 TLI.isOperationLegalOrCustom(ISD::SELECT_CC, VT)) 3890 return DAG.getNode(ISD::SELECT_CC, N->getDebugLoc(), VT, 3891 N0.getOperand(0), N0.getOperand(1), 3892 N1, N2, N0.getOperand(2)); 3893 return SimplifySelect(N->getDebugLoc(), N0, N1, N2); 3894 } 3895 3896 return SDValue(); 3897} 3898 3899SDValue DAGCombiner::visitSELECT_CC(SDNode *N) { 3900 SDValue N0 = N->getOperand(0); 3901 SDValue N1 = N->getOperand(1); 3902 SDValue N2 = N->getOperand(2); 3903 SDValue N3 = N->getOperand(3); 3904 SDValue N4 = N->getOperand(4); 3905 ISD::CondCode CC = cast<CondCodeSDNode>(N4)->get(); 3906 3907 // fold select_cc lhs, rhs, x, x, cc -> x 3908 if (N2 == N3) 3909 return N2; 3910 3911 // Determine if the condition we're dealing with is constant 3912 SDValue SCC = SimplifySetCC(TLI.getSetCCResultType(N0.getValueType()), 3913 N0, N1, CC, N->getDebugLoc(), false); 3914 if (SCC.getNode()) AddToWorkList(SCC.getNode()); 3915 3916 if (ConstantSDNode *SCCC = dyn_cast_or_null<ConstantSDNode>(SCC.getNode())) { 3917 if (!SCCC->isNullValue()) 3918 return N2; // cond always true -> true val 3919 else 3920 return N3; // cond always false -> false val 3921 } 3922 3923 // Fold to a simpler select_cc 3924 if (SCC.getNode() && SCC.getOpcode() == ISD::SETCC) 3925 return DAG.getNode(ISD::SELECT_CC, N->getDebugLoc(), N2.getValueType(), 3926 SCC.getOperand(0), SCC.getOperand(1), N2, N3, 3927 SCC.getOperand(2)); 3928 3929 // If we can fold this based on the true/false value, do so. 3930 if (SimplifySelectOps(N, N2, N3)) 3931 return SDValue(N, 0); // Don't revisit N. 3932 3933 // fold select_cc into other things, such as min/max/abs 3934 return SimplifySelectCC(N->getDebugLoc(), N0, N1, N2, N3, CC); 3935} 3936 3937SDValue DAGCombiner::visitSETCC(SDNode *N) { 3938 return SimplifySetCC(N->getValueType(0), N->getOperand(0), N->getOperand(1), 3939 cast<CondCodeSDNode>(N->getOperand(2))->get(), 3940 N->getDebugLoc()); 3941} 3942 3943// ExtendUsesToFormExtLoad - Trying to extend uses of a load to enable this: 3944// "fold ({s|z|a}ext (load x)) -> ({s|z|a}ext (truncate ({s|z|a}extload x)))" 3945// transformation. Returns true if extension are possible and the above 3946// mentioned transformation is profitable. 3947static bool ExtendUsesToFormExtLoad(SDNode *N, SDValue N0, 3948 unsigned ExtOpc, 3949 SmallVector<SDNode*, 4> &ExtendNodes, 3950 const TargetLowering &TLI) { 3951 bool HasCopyToRegUses = false; 3952 bool isTruncFree = TLI.isTruncateFree(N->getValueType(0), N0.getValueType()); 3953 for (SDNode::use_iterator UI = N0.getNode()->use_begin(), 3954 UE = N0.getNode()->use_end(); 3955 UI != UE; ++UI) { 3956 SDNode *User = *UI; 3957 if (User == N) 3958 continue; 3959 if (UI.getUse().getResNo() != N0.getResNo()) 3960 continue; 3961 // FIXME: Only extend SETCC N, N and SETCC N, c for now. 3962 if (ExtOpc != ISD::ANY_EXTEND && User->getOpcode() == ISD::SETCC) { 3963 ISD::CondCode CC = cast<CondCodeSDNode>(User->getOperand(2))->get(); 3964 if (ExtOpc == ISD::ZERO_EXTEND && ISD::isSignedIntSetCC(CC)) 3965 // Sign bits will be lost after a zext. 3966 return false; 3967 bool Add = false; 3968 for (unsigned i = 0; i != 2; ++i) { 3969 SDValue UseOp = User->getOperand(i); 3970 if (UseOp == N0) 3971 continue; 3972 if (!isa<ConstantSDNode>(UseOp)) 3973 return false; 3974 Add = true; 3975 } 3976 if (Add) 3977 ExtendNodes.push_back(User); 3978 continue; 3979 } 3980 // If truncates aren't free and there are users we can't 3981 // extend, it isn't worthwhile. 3982 if (!isTruncFree) 3983 return false; 3984 // Remember if this value is live-out. 3985 if (User->getOpcode() == ISD::CopyToReg) 3986 HasCopyToRegUses = true; 3987 } 3988 3989 if (HasCopyToRegUses) { 3990 bool BothLiveOut = false; 3991 for (SDNode::use_iterator UI = N->use_begin(), UE = N->use_end(); 3992 UI != UE; ++UI) { 3993 SDUse &Use = UI.getUse(); 3994 if (Use.getResNo() == 0 && Use.getUser()->getOpcode() == ISD::CopyToReg) { 3995 BothLiveOut = true; 3996 break; 3997 } 3998 } 3999 if (BothLiveOut) 4000 // Both unextended and extended values are live out. There had better be 4001 // a good reason for the transformation. 4002 return ExtendNodes.size(); 4003 } 4004 return true; 4005} 4006 4007void DAGCombiner::ExtendSetCCUses(SmallVector<SDNode*, 4> SetCCs, 4008 SDValue Trunc, SDValue ExtLoad, DebugLoc DL, 4009 ISD::NodeType ExtType) { 4010 // Extend SetCC uses if necessary. 4011 for (unsigned i = 0, e = SetCCs.size(); i != e; ++i) { 4012 SDNode *SetCC = SetCCs[i]; 4013 SmallVector<SDValue, 4> Ops; 4014 4015 for (unsigned j = 0; j != 2; ++j) { 4016 SDValue SOp = SetCC->getOperand(j); 4017 if (SOp == Trunc) 4018 Ops.push_back(ExtLoad); 4019 else 4020 Ops.push_back(DAG.getNode(ExtType, DL, ExtLoad->getValueType(0), SOp)); 4021 } 4022 4023 Ops.push_back(SetCC->getOperand(2)); 4024 CombineTo(SetCC, DAG.getNode(ISD::SETCC, DL, SetCC->getValueType(0), 4025 &Ops[0], Ops.size())); 4026 } 4027} 4028 4029SDValue DAGCombiner::visitSIGN_EXTEND(SDNode *N) { 4030 SDValue N0 = N->getOperand(0); 4031 EVT VT = N->getValueType(0); 4032 4033 // fold (sext c1) -> c1 4034 if (isa<ConstantSDNode>(N0)) 4035 return DAG.getNode(ISD::SIGN_EXTEND, N->getDebugLoc(), VT, N0); 4036 4037 // fold (sext (sext x)) -> (sext x) 4038 // fold (sext (aext x)) -> (sext x) 4039 if (N0.getOpcode() == ISD::SIGN_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND) 4040 return DAG.getNode(ISD::SIGN_EXTEND, N->getDebugLoc(), VT, 4041 N0.getOperand(0)); 4042 4043 if (N0.getOpcode() == ISD::TRUNCATE) { 4044 // fold (sext (truncate (load x))) -> (sext (smaller load x)) 4045 // fold (sext (truncate (srl (load x), c))) -> (sext (smaller load (x+c/n))) 4046 SDValue NarrowLoad = ReduceLoadWidth(N0.getNode()); 4047 if (NarrowLoad.getNode()) { 4048 SDNode* oye = N0.getNode()->getOperand(0).getNode(); 4049 if (NarrowLoad.getNode() != N0.getNode()) { 4050 CombineTo(N0.getNode(), NarrowLoad); 4051 // CombineTo deleted the truncate, if needed, but not what's under it. 4052 AddToWorkList(oye); 4053 } 4054 return SDValue(N, 0); // Return N so it doesn't get rechecked! 4055 } 4056 4057 // See if the value being truncated is already sign extended. If so, just 4058 // eliminate the trunc/sext pair. 4059 SDValue Op = N0.getOperand(0); 4060 unsigned OpBits = Op.getValueType().getScalarType().getSizeInBits(); 4061 unsigned MidBits = N0.getValueType().getScalarType().getSizeInBits(); 4062 unsigned DestBits = VT.getScalarType().getSizeInBits(); 4063 unsigned NumSignBits = DAG.ComputeNumSignBits(Op); 4064 4065 if (OpBits == DestBits) { 4066 // Op is i32, Mid is i8, and Dest is i32. If Op has more than 24 sign 4067 // bits, it is already ready. 4068 if (NumSignBits > DestBits-MidBits) 4069 return Op; 4070 } else if (OpBits < DestBits) { 4071 // Op is i32, Mid is i8, and Dest is i64. If Op has more than 24 sign 4072 // bits, just sext from i32. 4073 if (NumSignBits > OpBits-MidBits) 4074 return DAG.getNode(ISD::SIGN_EXTEND, N->getDebugLoc(), VT, Op); 4075 } else { 4076 // Op is i64, Mid is i8, and Dest is i32. If Op has more than 56 sign 4077 // bits, just truncate to i32. 4078 if (NumSignBits > OpBits-MidBits) 4079 return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, Op); 4080 } 4081 4082 // fold (sext (truncate x)) -> (sextinreg x). 4083 if (!LegalOperations || TLI.isOperationLegal(ISD::SIGN_EXTEND_INREG, 4084 N0.getValueType())) { 4085 if (OpBits < DestBits) 4086 Op = DAG.getNode(ISD::ANY_EXTEND, N0.getDebugLoc(), VT, Op); 4087 else if (OpBits > DestBits) 4088 Op = DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(), VT, Op); 4089 return DAG.getNode(ISD::SIGN_EXTEND_INREG, N->getDebugLoc(), VT, Op, 4090 DAG.getValueType(N0.getValueType())); 4091 } 4092 } 4093 4094 // fold (sext (load x)) -> (sext (truncate (sextload x))) 4095 // None of the supported targets knows how to perform load and sign extend 4096 // on vectors in one instruction. We only perform this transformation on 4097 // scalars. 4098 if (ISD::isNON_EXTLoad(N0.getNode()) && !VT.isVector() && 4099 ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) || 4100 TLI.isLoadExtLegal(ISD::SEXTLOAD, N0.getValueType()))) { 4101 bool DoXform = true; 4102 SmallVector<SDNode*, 4> SetCCs; 4103 if (!N0.hasOneUse()) 4104 DoXform = ExtendUsesToFormExtLoad(N, N0, ISD::SIGN_EXTEND, SetCCs, TLI); 4105 if (DoXform) { 4106 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 4107 SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, N->getDebugLoc(), VT, 4108 LN0->getChain(), 4109 LN0->getBasePtr(), LN0->getPointerInfo(), 4110 N0.getValueType(), 4111 LN0->isVolatile(), LN0->isNonTemporal(), 4112 LN0->getAlignment()); 4113 CombineTo(N, ExtLoad); 4114 SDValue Trunc = DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(), 4115 N0.getValueType(), ExtLoad); 4116 CombineTo(N0.getNode(), Trunc, ExtLoad.getValue(1)); 4117 ExtendSetCCUses(SetCCs, Trunc, ExtLoad, N->getDebugLoc(), 4118 ISD::SIGN_EXTEND); 4119 return SDValue(N, 0); // Return N so it doesn't get rechecked! 4120 } 4121 } 4122 4123 // fold (sext (sextload x)) -> (sext (truncate (sextload x))) 4124 // fold (sext ( extload x)) -> (sext (truncate (sextload x))) 4125 if ((ISD::isSEXTLoad(N0.getNode()) || ISD::isEXTLoad(N0.getNode())) && 4126 ISD::isUNINDEXEDLoad(N0.getNode()) && N0.hasOneUse()) { 4127 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 4128 EVT MemVT = LN0->getMemoryVT(); 4129 if ((!LegalOperations && !LN0->isVolatile()) || 4130 TLI.isLoadExtLegal(ISD::SEXTLOAD, MemVT)) { 4131 SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, N->getDebugLoc(), VT, 4132 LN0->getChain(), 4133 LN0->getBasePtr(), LN0->getPointerInfo(), 4134 MemVT, 4135 LN0->isVolatile(), LN0->isNonTemporal(), 4136 LN0->getAlignment()); 4137 CombineTo(N, ExtLoad); 4138 CombineTo(N0.getNode(), 4139 DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(), 4140 N0.getValueType(), ExtLoad), 4141 ExtLoad.getValue(1)); 4142 return SDValue(N, 0); // Return N so it doesn't get rechecked! 4143 } 4144 } 4145 4146 // fold (sext (and/or/xor (load x), cst)) -> 4147 // (and/or/xor (sextload x), (sext cst)) 4148 if ((N0.getOpcode() == ISD::AND || N0.getOpcode() == ISD::OR || 4149 N0.getOpcode() == ISD::XOR) && 4150 isa<LoadSDNode>(N0.getOperand(0)) && 4151 N0.getOperand(1).getOpcode() == ISD::Constant && 4152 TLI.isLoadExtLegal(ISD::SEXTLOAD, N0.getValueType()) && 4153 (!LegalOperations && TLI.isOperationLegal(N0.getOpcode(), VT))) { 4154 LoadSDNode *LN0 = cast<LoadSDNode>(N0.getOperand(0)); 4155 if (LN0->getExtensionType() != ISD::ZEXTLOAD) { 4156 bool DoXform = true; 4157 SmallVector<SDNode*, 4> SetCCs; 4158 if (!N0.hasOneUse()) 4159 DoXform = ExtendUsesToFormExtLoad(N, N0.getOperand(0), ISD::SIGN_EXTEND, 4160 SetCCs, TLI); 4161 if (DoXform) { 4162 SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, LN0->getDebugLoc(), VT, 4163 LN0->getChain(), LN0->getBasePtr(), 4164 LN0->getPointerInfo(), 4165 LN0->getMemoryVT(), 4166 LN0->isVolatile(), 4167 LN0->isNonTemporal(), 4168 LN0->getAlignment()); 4169 APInt Mask = cast<ConstantSDNode>(N0.getOperand(1))->getAPIntValue(); 4170 Mask = Mask.sext(VT.getSizeInBits()); 4171 SDValue And = DAG.getNode(N0.getOpcode(), N->getDebugLoc(), VT, 4172 ExtLoad, DAG.getConstant(Mask, VT)); 4173 SDValue Trunc = DAG.getNode(ISD::TRUNCATE, 4174 N0.getOperand(0).getDebugLoc(), 4175 N0.getOperand(0).getValueType(), ExtLoad); 4176 CombineTo(N, And); 4177 CombineTo(N0.getOperand(0).getNode(), Trunc, ExtLoad.getValue(1)); 4178 ExtendSetCCUses(SetCCs, Trunc, ExtLoad, N->getDebugLoc(), 4179 ISD::SIGN_EXTEND); 4180 return SDValue(N, 0); // Return N so it doesn't get rechecked! 4181 } 4182 } 4183 } 4184 4185 if (N0.getOpcode() == ISD::SETCC) { 4186 // sext(setcc) -> sext_in_reg(vsetcc) for vectors. 4187 // Only do this before legalize for now. 4188 if (VT.isVector() && !LegalOperations) { 4189 EVT N0VT = N0.getOperand(0).getValueType(); 4190 // We know that the # elements of the results is the same as the 4191 // # elements of the compare (and the # elements of the compare result 4192 // for that matter). Check to see that they are the same size. If so, 4193 // we know that the element size of the sext'd result matches the 4194 // element size of the compare operands. 4195 if (VT.getSizeInBits() == N0VT.getSizeInBits()) 4196 return DAG.getSetCC(N->getDebugLoc(), VT, N0.getOperand(0), 4197 N0.getOperand(1), 4198 cast<CondCodeSDNode>(N0.getOperand(2))->get()); 4199 // If the desired elements are smaller or larger than the source 4200 // elements we can use a matching integer vector type and then 4201 // truncate/sign extend 4202 else { 4203 EVT MatchingElementType = 4204 EVT::getIntegerVT(*DAG.getContext(), 4205 N0VT.getScalarType().getSizeInBits()); 4206 EVT MatchingVectorType = 4207 EVT::getVectorVT(*DAG.getContext(), MatchingElementType, 4208 N0VT.getVectorNumElements()); 4209 SDValue VsetCC = 4210 DAG.getSetCC(N->getDebugLoc(), MatchingVectorType, N0.getOperand(0), 4211 N0.getOperand(1), 4212 cast<CondCodeSDNode>(N0.getOperand(2))->get()); 4213 return DAG.getSExtOrTrunc(VsetCC, N->getDebugLoc(), VT); 4214 } 4215 } 4216 4217 // sext(setcc x, y, cc) -> (select_cc x, y, -1, 0, cc) 4218 unsigned ElementWidth = VT.getScalarType().getSizeInBits(); 4219 SDValue NegOne = 4220 DAG.getConstant(APInt::getAllOnesValue(ElementWidth), VT); 4221 SDValue SCC = 4222 SimplifySelectCC(N->getDebugLoc(), N0.getOperand(0), N0.getOperand(1), 4223 NegOne, DAG.getConstant(0, VT), 4224 cast<CondCodeSDNode>(N0.getOperand(2))->get(), true); 4225 if (SCC.getNode()) return SCC; 4226 if (!LegalOperations || 4227 TLI.isOperationLegal(ISD::SETCC, TLI.getSetCCResultType(VT))) 4228 return DAG.getNode(ISD::SELECT, N->getDebugLoc(), VT, 4229 DAG.getSetCC(N->getDebugLoc(), 4230 TLI.getSetCCResultType(VT), 4231 N0.getOperand(0), N0.getOperand(1), 4232 cast<CondCodeSDNode>(N0.getOperand(2))->get()), 4233 NegOne, DAG.getConstant(0, VT)); 4234 } 4235 4236 // fold (sext x) -> (zext x) if the sign bit is known zero. 4237 if ((!LegalOperations || TLI.isOperationLegal(ISD::ZERO_EXTEND, VT)) && 4238 DAG.SignBitIsZero(N0)) 4239 return DAG.getNode(ISD::ZERO_EXTEND, N->getDebugLoc(), VT, N0); 4240 4241 return SDValue(); 4242} 4243 4244SDValue DAGCombiner::visitZERO_EXTEND(SDNode *N) { 4245 SDValue N0 = N->getOperand(0); 4246 EVT VT = N->getValueType(0); 4247 4248 // fold (zext c1) -> c1 4249 if (isa<ConstantSDNode>(N0)) 4250 return DAG.getNode(ISD::ZERO_EXTEND, N->getDebugLoc(), VT, N0); 4251 // fold (zext (zext x)) -> (zext x) 4252 // fold (zext (aext x)) -> (zext x) 4253 if (N0.getOpcode() == ISD::ZERO_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND) 4254 return DAG.getNode(ISD::ZERO_EXTEND, N->getDebugLoc(), VT, 4255 N0.getOperand(0)); 4256 4257 // fold (zext (truncate x)) -> (zext x) or 4258 // (zext (truncate x)) -> (truncate x) 4259 // This is valid when the truncated bits of x are already zero. 4260 // FIXME: We should extend this to work for vectors too. 4261 if (N0.getOpcode() == ISD::TRUNCATE && !VT.isVector()) { 4262 SDValue Op = N0.getOperand(0); 4263 APInt TruncatedBits 4264 = APInt::getBitsSet(Op.getValueSizeInBits(), 4265 N0.getValueSizeInBits(), 4266 std::min(Op.getValueSizeInBits(), 4267 VT.getSizeInBits())); 4268 APInt KnownZero, KnownOne; 4269 DAG.ComputeMaskedBits(Op, TruncatedBits, KnownZero, KnownOne); 4270 if (TruncatedBits == KnownZero) { 4271 if (VT.bitsGT(Op.getValueType())) 4272 return DAG.getNode(ISD::ZERO_EXTEND, N->getDebugLoc(), VT, Op); 4273 if (VT.bitsLT(Op.getValueType())) 4274 return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, Op); 4275 4276 return Op; 4277 } 4278 } 4279 4280 // fold (zext (truncate (load x))) -> (zext (smaller load x)) 4281 // fold (zext (truncate (srl (load x), c))) -> (zext (small load (x+c/n))) 4282 if (N0.getOpcode() == ISD::TRUNCATE) { 4283 SDValue NarrowLoad = ReduceLoadWidth(N0.getNode()); 4284 if (NarrowLoad.getNode()) { 4285 SDNode* oye = N0.getNode()->getOperand(0).getNode(); 4286 if (NarrowLoad.getNode() != N0.getNode()) { 4287 CombineTo(N0.getNode(), NarrowLoad); 4288 // CombineTo deleted the truncate, if needed, but not what's under it. 4289 AddToWorkList(oye); 4290 } 4291 return SDValue(N, 0); // Return N so it doesn't get rechecked! 4292 } 4293 } 4294 4295 // fold (zext (truncate x)) -> (and x, mask) 4296 if (N0.getOpcode() == ISD::TRUNCATE && 4297 (!LegalOperations || TLI.isOperationLegal(ISD::AND, VT))) { 4298 4299 // fold (zext (truncate (load x))) -> (zext (smaller load x)) 4300 // fold (zext (truncate (srl (load x), c))) -> (zext (smaller load (x+c/n))) 4301 SDValue NarrowLoad = ReduceLoadWidth(N0.getNode()); 4302 if (NarrowLoad.getNode()) { 4303 SDNode* oye = N0.getNode()->getOperand(0).getNode(); 4304 if (NarrowLoad.getNode() != N0.getNode()) { 4305 CombineTo(N0.getNode(), NarrowLoad); 4306 // CombineTo deleted the truncate, if needed, but not what's under it. 4307 AddToWorkList(oye); 4308 } 4309 return SDValue(N, 0); // Return N so it doesn't get rechecked! 4310 } 4311 4312 SDValue Op = N0.getOperand(0); 4313 if (Op.getValueType().bitsLT(VT)) { 4314 Op = DAG.getNode(ISD::ANY_EXTEND, N->getDebugLoc(), VT, Op); 4315 } else if (Op.getValueType().bitsGT(VT)) { 4316 Op = DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, Op); 4317 } 4318 return DAG.getZeroExtendInReg(Op, N->getDebugLoc(), 4319 N0.getValueType().getScalarType()); 4320 } 4321 4322 // Fold (zext (and (trunc x), cst)) -> (and x, cst), 4323 // if either of the casts is not free. 4324 if (N0.getOpcode() == ISD::AND && 4325 N0.getOperand(0).getOpcode() == ISD::TRUNCATE && 4326 N0.getOperand(1).getOpcode() == ISD::Constant && 4327 (!TLI.isTruncateFree(N0.getOperand(0).getOperand(0).getValueType(), 4328 N0.getValueType()) || 4329 !TLI.isZExtFree(N0.getValueType(), VT))) { 4330 SDValue X = N0.getOperand(0).getOperand(0); 4331 if (X.getValueType().bitsLT(VT)) { 4332 X = DAG.getNode(ISD::ANY_EXTEND, X.getDebugLoc(), VT, X); 4333 } else if (X.getValueType().bitsGT(VT)) { 4334 X = DAG.getNode(ISD::TRUNCATE, X.getDebugLoc(), VT, X); 4335 } 4336 APInt Mask = cast<ConstantSDNode>(N0.getOperand(1))->getAPIntValue(); 4337 Mask = Mask.zext(VT.getSizeInBits()); 4338 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, 4339 X, DAG.getConstant(Mask, VT)); 4340 } 4341 4342 // fold (zext (load x)) -> (zext (truncate (zextload x))) 4343 // None of the supported targets knows how to perform load and vector_zext 4344 // on vectors in one instruction. We only perform this transformation on 4345 // scalars. 4346 if (ISD::isNON_EXTLoad(N0.getNode()) && !VT.isVector() && 4347 ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) || 4348 TLI.isLoadExtLegal(ISD::ZEXTLOAD, N0.getValueType()))) { 4349 bool DoXform = true; 4350 SmallVector<SDNode*, 4> SetCCs; 4351 if (!N0.hasOneUse()) 4352 DoXform = ExtendUsesToFormExtLoad(N, N0, ISD::ZERO_EXTEND, SetCCs, TLI); 4353 if (DoXform) { 4354 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 4355 SDValue ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, N->getDebugLoc(), VT, 4356 LN0->getChain(), 4357 LN0->getBasePtr(), LN0->getPointerInfo(), 4358 N0.getValueType(), 4359 LN0->isVolatile(), LN0->isNonTemporal(), 4360 LN0->getAlignment()); 4361 CombineTo(N, ExtLoad); 4362 SDValue Trunc = DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(), 4363 N0.getValueType(), ExtLoad); 4364 CombineTo(N0.getNode(), Trunc, ExtLoad.getValue(1)); 4365 4366 ExtendSetCCUses(SetCCs, Trunc, ExtLoad, N->getDebugLoc(), 4367 ISD::ZERO_EXTEND); 4368 return SDValue(N, 0); // Return N so it doesn't get rechecked! 4369 } 4370 } 4371 4372 // fold (zext (and/or/xor (load x), cst)) -> 4373 // (and/or/xor (zextload x), (zext cst)) 4374 if ((N0.getOpcode() == ISD::AND || N0.getOpcode() == ISD::OR || 4375 N0.getOpcode() == ISD::XOR) && 4376 isa<LoadSDNode>(N0.getOperand(0)) && 4377 N0.getOperand(1).getOpcode() == ISD::Constant && 4378 TLI.isLoadExtLegal(ISD::ZEXTLOAD, N0.getValueType()) && 4379 (!LegalOperations && TLI.isOperationLegal(N0.getOpcode(), VT))) { 4380 LoadSDNode *LN0 = cast<LoadSDNode>(N0.getOperand(0)); 4381 if (LN0->getExtensionType() != ISD::SEXTLOAD) { 4382 bool DoXform = true; 4383 SmallVector<SDNode*, 4> SetCCs; 4384 if (!N0.hasOneUse()) 4385 DoXform = ExtendUsesToFormExtLoad(N, N0.getOperand(0), ISD::ZERO_EXTEND, 4386 SetCCs, TLI); 4387 if (DoXform) { 4388 SDValue ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, LN0->getDebugLoc(), VT, 4389 LN0->getChain(), LN0->getBasePtr(), 4390 LN0->getPointerInfo(), 4391 LN0->getMemoryVT(), 4392 LN0->isVolatile(), 4393 LN0->isNonTemporal(), 4394 LN0->getAlignment()); 4395 APInt Mask = cast<ConstantSDNode>(N0.getOperand(1))->getAPIntValue(); 4396 Mask = Mask.zext(VT.getSizeInBits()); 4397 SDValue And = DAG.getNode(N0.getOpcode(), N->getDebugLoc(), VT, 4398 ExtLoad, DAG.getConstant(Mask, VT)); 4399 SDValue Trunc = DAG.getNode(ISD::TRUNCATE, 4400 N0.getOperand(0).getDebugLoc(), 4401 N0.getOperand(0).getValueType(), ExtLoad); 4402 CombineTo(N, And); 4403 CombineTo(N0.getOperand(0).getNode(), Trunc, ExtLoad.getValue(1)); 4404 ExtendSetCCUses(SetCCs, Trunc, ExtLoad, N->getDebugLoc(), 4405 ISD::ZERO_EXTEND); 4406 return SDValue(N, 0); // Return N so it doesn't get rechecked! 4407 } 4408 } 4409 } 4410 4411 // fold (zext (zextload x)) -> (zext (truncate (zextload x))) 4412 // fold (zext ( extload x)) -> (zext (truncate (zextload x))) 4413 if ((ISD::isZEXTLoad(N0.getNode()) || ISD::isEXTLoad(N0.getNode())) && 4414 ISD::isUNINDEXEDLoad(N0.getNode()) && N0.hasOneUse()) { 4415 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 4416 EVT MemVT = LN0->getMemoryVT(); 4417 if ((!LegalOperations && !LN0->isVolatile()) || 4418 TLI.isLoadExtLegal(ISD::ZEXTLOAD, MemVT)) { 4419 SDValue ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, N->getDebugLoc(), VT, 4420 LN0->getChain(), 4421 LN0->getBasePtr(), LN0->getPointerInfo(), 4422 MemVT, 4423 LN0->isVolatile(), LN0->isNonTemporal(), 4424 LN0->getAlignment()); 4425 CombineTo(N, ExtLoad); 4426 CombineTo(N0.getNode(), 4427 DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(), N0.getValueType(), 4428 ExtLoad), 4429 ExtLoad.getValue(1)); 4430 return SDValue(N, 0); // Return N so it doesn't get rechecked! 4431 } 4432 } 4433 4434 if (N0.getOpcode() == ISD::SETCC) { 4435 if (!LegalOperations && VT.isVector()) { 4436 // zext(setcc) -> (and (vsetcc), (1, 1, ...) for vectors. 4437 // Only do this before legalize for now. 4438 EVT N0VT = N0.getOperand(0).getValueType(); 4439 EVT EltVT = VT.getVectorElementType(); 4440 SmallVector<SDValue,8> OneOps(VT.getVectorNumElements(), 4441 DAG.getConstant(1, EltVT)); 4442 if (VT.getSizeInBits() == N0VT.getSizeInBits()) 4443 // We know that the # elements of the results is the same as the 4444 // # elements of the compare (and the # elements of the compare result 4445 // for that matter). Check to see that they are the same size. If so, 4446 // we know that the element size of the sext'd result matches the 4447 // element size of the compare operands. 4448 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, 4449 DAG.getSetCC(N->getDebugLoc(), VT, N0.getOperand(0), 4450 N0.getOperand(1), 4451 cast<CondCodeSDNode>(N0.getOperand(2))->get()), 4452 DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(), VT, 4453 &OneOps[0], OneOps.size())); 4454 4455 // If the desired elements are smaller or larger than the source 4456 // elements we can use a matching integer vector type and then 4457 // truncate/sign extend 4458 EVT MatchingElementType = 4459 EVT::getIntegerVT(*DAG.getContext(), 4460 N0VT.getScalarType().getSizeInBits()); 4461 EVT MatchingVectorType = 4462 EVT::getVectorVT(*DAG.getContext(), MatchingElementType, 4463 N0VT.getVectorNumElements()); 4464 SDValue VsetCC = 4465 DAG.getSetCC(N->getDebugLoc(), MatchingVectorType, N0.getOperand(0), 4466 N0.getOperand(1), 4467 cast<CondCodeSDNode>(N0.getOperand(2))->get()); 4468 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, 4469 DAG.getSExtOrTrunc(VsetCC, N->getDebugLoc(), VT), 4470 DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(), VT, 4471 &OneOps[0], OneOps.size())); 4472 } 4473 4474 // zext(setcc x,y,cc) -> select_cc x, y, 1, 0, cc 4475 SDValue SCC = 4476 SimplifySelectCC(N->getDebugLoc(), N0.getOperand(0), N0.getOperand(1), 4477 DAG.getConstant(1, VT), DAG.getConstant(0, VT), 4478 cast<CondCodeSDNode>(N0.getOperand(2))->get(), true); 4479 if (SCC.getNode()) return SCC; 4480 } 4481 4482 // (zext (shl (zext x), cst)) -> (shl (zext x), cst) 4483 if ((N0.getOpcode() == ISD::SHL || N0.getOpcode() == ISD::SRL) && 4484 isa<ConstantSDNode>(N0.getOperand(1)) && 4485 N0.getOperand(0).getOpcode() == ISD::ZERO_EXTEND && 4486 N0.hasOneUse()) { 4487 SDValue ShAmt = N0.getOperand(1); 4488 unsigned ShAmtVal = cast<ConstantSDNode>(ShAmt)->getZExtValue(); 4489 if (N0.getOpcode() == ISD::SHL) { 4490 SDValue InnerZExt = N0.getOperand(0); 4491 // If the original shl may be shifting out bits, do not perform this 4492 // transformation. 4493 unsigned KnownZeroBits = InnerZExt.getValueType().getSizeInBits() - 4494 InnerZExt.getOperand(0).getValueType().getSizeInBits(); 4495 if (ShAmtVal > KnownZeroBits) 4496 return SDValue(); 4497 } 4498 4499 DebugLoc DL = N->getDebugLoc(); 4500 4501 // Ensure that the shift amount is wide enough for the shifted value. 4502 if (VT.getSizeInBits() >= 256) 4503 ShAmt = DAG.getNode(ISD::ZERO_EXTEND, DL, MVT::i32, ShAmt); 4504 4505 return DAG.getNode(N0.getOpcode(), DL, VT, 4506 DAG.getNode(ISD::ZERO_EXTEND, DL, VT, N0.getOperand(0)), 4507 ShAmt); 4508 } 4509 4510 return SDValue(); 4511} 4512 4513SDValue DAGCombiner::visitANY_EXTEND(SDNode *N) { 4514 SDValue N0 = N->getOperand(0); 4515 EVT VT = N->getValueType(0); 4516 4517 // fold (aext c1) -> c1 4518 if (isa<ConstantSDNode>(N0)) 4519 return DAG.getNode(ISD::ANY_EXTEND, N->getDebugLoc(), VT, N0); 4520 // fold (aext (aext x)) -> (aext x) 4521 // fold (aext (zext x)) -> (zext x) 4522 // fold (aext (sext x)) -> (sext x) 4523 if (N0.getOpcode() == ISD::ANY_EXTEND || 4524 N0.getOpcode() == ISD::ZERO_EXTEND || 4525 N0.getOpcode() == ISD::SIGN_EXTEND) 4526 return DAG.getNode(N0.getOpcode(), N->getDebugLoc(), VT, N0.getOperand(0)); 4527 4528 // fold (aext (truncate (load x))) -> (aext (smaller load x)) 4529 // fold (aext (truncate (srl (load x), c))) -> (aext (small load (x+c/n))) 4530 if (N0.getOpcode() == ISD::TRUNCATE) { 4531 SDValue NarrowLoad = ReduceLoadWidth(N0.getNode()); 4532 if (NarrowLoad.getNode()) { 4533 SDNode* oye = N0.getNode()->getOperand(0).getNode(); 4534 if (NarrowLoad.getNode() != N0.getNode()) { 4535 CombineTo(N0.getNode(), NarrowLoad); 4536 // CombineTo deleted the truncate, if needed, but not what's under it. 4537 AddToWorkList(oye); 4538 } 4539 return SDValue(N, 0); // Return N so it doesn't get rechecked! 4540 } 4541 } 4542 4543 // fold (aext (truncate x)) 4544 if (N0.getOpcode() == ISD::TRUNCATE) { 4545 SDValue TruncOp = N0.getOperand(0); 4546 if (TruncOp.getValueType() == VT) 4547 return TruncOp; // x iff x size == zext size. 4548 if (TruncOp.getValueType().bitsGT(VT)) 4549 return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, TruncOp); 4550 return DAG.getNode(ISD::ANY_EXTEND, N->getDebugLoc(), VT, TruncOp); 4551 } 4552 4553 // Fold (aext (and (trunc x), cst)) -> (and x, cst) 4554 // if the trunc is not free. 4555 if (N0.getOpcode() == ISD::AND && 4556 N0.getOperand(0).getOpcode() == ISD::TRUNCATE && 4557 N0.getOperand(1).getOpcode() == ISD::Constant && 4558 !TLI.isTruncateFree(N0.getOperand(0).getOperand(0).getValueType(), 4559 N0.getValueType())) { 4560 SDValue X = N0.getOperand(0).getOperand(0); 4561 if (X.getValueType().bitsLT(VT)) { 4562 X = DAG.getNode(ISD::ANY_EXTEND, N->getDebugLoc(), VT, X); 4563 } else if (X.getValueType().bitsGT(VT)) { 4564 X = DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, X); 4565 } 4566 APInt Mask = cast<ConstantSDNode>(N0.getOperand(1))->getAPIntValue(); 4567 Mask = Mask.zext(VT.getSizeInBits()); 4568 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, 4569 X, DAG.getConstant(Mask, VT)); 4570 } 4571 4572 // fold (aext (load x)) -> (aext (truncate (extload x))) 4573 // None of the supported targets knows how to perform load and any_ext 4574 // on vectors in one instruction. We only perform this transformation on 4575 // scalars. 4576 if (ISD::isNON_EXTLoad(N0.getNode()) && !VT.isVector() && 4577 ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) || 4578 TLI.isLoadExtLegal(ISD::EXTLOAD, N0.getValueType()))) { 4579 bool DoXform = true; 4580 SmallVector<SDNode*, 4> SetCCs; 4581 if (!N0.hasOneUse()) 4582 DoXform = ExtendUsesToFormExtLoad(N, N0, ISD::ANY_EXTEND, SetCCs, TLI); 4583 if (DoXform) { 4584 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 4585 SDValue ExtLoad = DAG.getExtLoad(ISD::EXTLOAD, N->getDebugLoc(), VT, 4586 LN0->getChain(), 4587 LN0->getBasePtr(), LN0->getPointerInfo(), 4588 N0.getValueType(), 4589 LN0->isVolatile(), LN0->isNonTemporal(), 4590 LN0->getAlignment()); 4591 CombineTo(N, ExtLoad); 4592 SDValue Trunc = DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(), 4593 N0.getValueType(), ExtLoad); 4594 CombineTo(N0.getNode(), Trunc, ExtLoad.getValue(1)); 4595 ExtendSetCCUses(SetCCs, Trunc, ExtLoad, N->getDebugLoc(), 4596 ISD::ANY_EXTEND); 4597 return SDValue(N, 0); // Return N so it doesn't get rechecked! 4598 } 4599 } 4600 4601 // fold (aext (zextload x)) -> (aext (truncate (zextload x))) 4602 // fold (aext (sextload x)) -> (aext (truncate (sextload x))) 4603 // fold (aext ( extload x)) -> (aext (truncate (extload x))) 4604 if (N0.getOpcode() == ISD::LOAD && 4605 !ISD::isNON_EXTLoad(N0.getNode()) && ISD::isUNINDEXEDLoad(N0.getNode()) && 4606 N0.hasOneUse()) { 4607 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 4608 EVT MemVT = LN0->getMemoryVT(); 4609 SDValue ExtLoad = DAG.getExtLoad(LN0->getExtensionType(), N->getDebugLoc(), 4610 VT, LN0->getChain(), LN0->getBasePtr(), 4611 LN0->getPointerInfo(), MemVT, 4612 LN0->isVolatile(), LN0->isNonTemporal(), 4613 LN0->getAlignment()); 4614 CombineTo(N, ExtLoad); 4615 CombineTo(N0.getNode(), 4616 DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(), 4617 N0.getValueType(), ExtLoad), 4618 ExtLoad.getValue(1)); 4619 return SDValue(N, 0); // Return N so it doesn't get rechecked! 4620 } 4621 4622 if (N0.getOpcode() == ISD::SETCC) { 4623 // aext(setcc) -> sext_in_reg(vsetcc) for vectors. 4624 // Only do this before legalize for now. 4625 if (VT.isVector() && !LegalOperations) { 4626 EVT N0VT = N0.getOperand(0).getValueType(); 4627 // We know that the # elements of the results is the same as the 4628 // # elements of the compare (and the # elements of the compare result 4629 // for that matter). Check to see that they are the same size. If so, 4630 // we know that the element size of the sext'd result matches the 4631 // element size of the compare operands. 4632 if (VT.getSizeInBits() == N0VT.getSizeInBits()) 4633 return DAG.getSetCC(N->getDebugLoc(), VT, N0.getOperand(0), 4634 N0.getOperand(1), 4635 cast<CondCodeSDNode>(N0.getOperand(2))->get()); 4636 // If the desired elements are smaller or larger than the source 4637 // elements we can use a matching integer vector type and then 4638 // truncate/sign extend 4639 else { 4640 EVT MatchingElementType = 4641 EVT::getIntegerVT(*DAG.getContext(), 4642 N0VT.getScalarType().getSizeInBits()); 4643 EVT MatchingVectorType = 4644 EVT::getVectorVT(*DAG.getContext(), MatchingElementType, 4645 N0VT.getVectorNumElements()); 4646 SDValue VsetCC = 4647 DAG.getSetCC(N->getDebugLoc(), MatchingVectorType, N0.getOperand(0), 4648 N0.getOperand(1), 4649 cast<CondCodeSDNode>(N0.getOperand(2))->get()); 4650 return DAG.getSExtOrTrunc(VsetCC, N->getDebugLoc(), VT); 4651 } 4652 } 4653 4654 // aext(setcc x,y,cc) -> select_cc x, y, 1, 0, cc 4655 SDValue SCC = 4656 SimplifySelectCC(N->getDebugLoc(), N0.getOperand(0), N0.getOperand(1), 4657 DAG.getConstant(1, VT), DAG.getConstant(0, VT), 4658 cast<CondCodeSDNode>(N0.getOperand(2))->get(), true); 4659 if (SCC.getNode()) 4660 return SCC; 4661 } 4662 4663 return SDValue(); 4664} 4665 4666/// GetDemandedBits - See if the specified operand can be simplified with the 4667/// knowledge that only the bits specified by Mask are used. If so, return the 4668/// simpler operand, otherwise return a null SDValue. 4669SDValue DAGCombiner::GetDemandedBits(SDValue V, const APInt &Mask) { 4670 switch (V.getOpcode()) { 4671 default: break; 4672 case ISD::Constant: { 4673 const ConstantSDNode *CV = cast<ConstantSDNode>(V.getNode()); 4674 assert(CV != 0 && "Const value should be ConstSDNode."); 4675 const APInt &CVal = CV->getAPIntValue(); 4676 APInt NewVal = CVal & Mask; 4677 if (NewVal != CVal) { 4678 return DAG.getConstant(NewVal, V.getValueType()); 4679 } 4680 break; 4681 } 4682 case ISD::OR: 4683 case ISD::XOR: 4684 // If the LHS or RHS don't contribute bits to the or, drop them. 4685 if (DAG.MaskedValueIsZero(V.getOperand(0), Mask)) 4686 return V.getOperand(1); 4687 if (DAG.MaskedValueIsZero(V.getOperand(1), Mask)) 4688 return V.getOperand(0); 4689 break; 4690 case ISD::SRL: 4691 // Only look at single-use SRLs. 4692 if (!V.getNode()->hasOneUse()) 4693 break; 4694 if (ConstantSDNode *RHSC = dyn_cast<ConstantSDNode>(V.getOperand(1))) { 4695 // See if we can recursively simplify the LHS. 4696 unsigned Amt = RHSC->getZExtValue(); 4697 4698 // Watch out for shift count overflow though. 4699 if (Amt >= Mask.getBitWidth()) break; 4700 APInt NewMask = Mask << Amt; 4701 SDValue SimplifyLHS = GetDemandedBits(V.getOperand(0), NewMask); 4702 if (SimplifyLHS.getNode()) 4703 return DAG.getNode(ISD::SRL, V.getDebugLoc(), V.getValueType(), 4704 SimplifyLHS, V.getOperand(1)); 4705 } 4706 } 4707 return SDValue(); 4708} 4709 4710/// ReduceLoadWidth - If the result of a wider load is shifted to right of N 4711/// bits and then truncated to a narrower type and where N is a multiple 4712/// of number of bits of the narrower type, transform it to a narrower load 4713/// from address + N / num of bits of new type. If the result is to be 4714/// extended, also fold the extension to form a extending load. 4715SDValue DAGCombiner::ReduceLoadWidth(SDNode *N) { 4716 unsigned Opc = N->getOpcode(); 4717 4718 ISD::LoadExtType ExtType = ISD::NON_EXTLOAD; 4719 SDValue N0 = N->getOperand(0); 4720 EVT VT = N->getValueType(0); 4721 EVT ExtVT = VT; 4722 4723 // This transformation isn't valid for vector loads. 4724 if (VT.isVector()) 4725 return SDValue(); 4726 4727 // Special case: SIGN_EXTEND_INREG is basically truncating to ExtVT then 4728 // extended to VT. 4729 if (Opc == ISD::SIGN_EXTEND_INREG) { 4730 ExtType = ISD::SEXTLOAD; 4731 ExtVT = cast<VTSDNode>(N->getOperand(1))->getVT(); 4732 } else if (Opc == ISD::SRL) { 4733 // Another special-case: SRL is basically zero-extending a narrower value. 4734 ExtType = ISD::ZEXTLOAD; 4735 N0 = SDValue(N, 0); 4736 ConstantSDNode *N01 = dyn_cast<ConstantSDNode>(N0.getOperand(1)); 4737 if (!N01) return SDValue(); 4738 ExtVT = EVT::getIntegerVT(*DAG.getContext(), 4739 VT.getSizeInBits() - N01->getZExtValue()); 4740 } 4741 if (LegalOperations && !TLI.isLoadExtLegal(ExtType, ExtVT)) 4742 return SDValue(); 4743 4744 unsigned EVTBits = ExtVT.getSizeInBits(); 4745 4746 // Do not generate loads of non-round integer types since these can 4747 // be expensive (and would be wrong if the type is not byte sized). 4748 if (!ExtVT.isRound()) 4749 return SDValue(); 4750 4751 unsigned ShAmt = 0; 4752 if (N0.getOpcode() == ISD::SRL && N0.hasOneUse()) { 4753 if (ConstantSDNode *N01 = dyn_cast<ConstantSDNode>(N0.getOperand(1))) { 4754 ShAmt = N01->getZExtValue(); 4755 // Is the shift amount a multiple of size of VT? 4756 if ((ShAmt & (EVTBits-1)) == 0) { 4757 N0 = N0.getOperand(0); 4758 // Is the load width a multiple of size of VT? 4759 if ((N0.getValueType().getSizeInBits() & (EVTBits-1)) != 0) 4760 return SDValue(); 4761 } 4762 4763 // At this point, we must have a load or else we can't do the transform. 4764 if (!isa<LoadSDNode>(N0)) return SDValue(); 4765 4766 // If the shift amount is larger than the input type then we're not 4767 // accessing any of the loaded bytes. If the load was a zextload/extload 4768 // then the result of the shift+trunc is zero/undef (handled elsewhere). 4769 // If the load was a sextload then the result is a splat of the sign bit 4770 // of the extended byte. This is not worth optimizing for. 4771 if (ShAmt >= cast<LoadSDNode>(N0)->getMemoryVT().getSizeInBits()) 4772 return SDValue(); 4773 } 4774 } 4775 4776 // If the load is shifted left (and the result isn't shifted back right), 4777 // we can fold the truncate through the shift. 4778 unsigned ShLeftAmt = 0; 4779 if (ShAmt == 0 && N0.getOpcode() == ISD::SHL && N0.hasOneUse() && 4780 ExtVT == VT && TLI.isNarrowingProfitable(N0.getValueType(), VT)) { 4781 if (ConstantSDNode *N01 = dyn_cast<ConstantSDNode>(N0.getOperand(1))) { 4782 ShLeftAmt = N01->getZExtValue(); 4783 N0 = N0.getOperand(0); 4784 } 4785 } 4786 4787 // If we haven't found a load, we can't narrow it. Don't transform one with 4788 // multiple uses, this would require adding a new load. 4789 if (!isa<LoadSDNode>(N0) || !N0.hasOneUse() || 4790 // Don't change the width of a volatile load. 4791 cast<LoadSDNode>(N0)->isVolatile()) 4792 return SDValue(); 4793 4794 // Verify that we are actually reducing a load width here. 4795 if (cast<LoadSDNode>(N0)->getMemoryVT().getSizeInBits() < EVTBits) 4796 return SDValue(); 4797 4798 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 4799 EVT PtrType = N0.getOperand(1).getValueType(); 4800 4801 // For big endian targets, we need to adjust the offset to the pointer to 4802 // load the correct bytes. 4803 if (TLI.isBigEndian()) { 4804 unsigned LVTStoreBits = LN0->getMemoryVT().getStoreSizeInBits(); 4805 unsigned EVTStoreBits = ExtVT.getStoreSizeInBits(); 4806 ShAmt = LVTStoreBits - EVTStoreBits - ShAmt; 4807 } 4808 4809 uint64_t PtrOff = ShAmt / 8; 4810 unsigned NewAlign = MinAlign(LN0->getAlignment(), PtrOff); 4811 SDValue NewPtr = DAG.getNode(ISD::ADD, LN0->getDebugLoc(), 4812 PtrType, LN0->getBasePtr(), 4813 DAG.getConstant(PtrOff, PtrType)); 4814 AddToWorkList(NewPtr.getNode()); 4815 4816 SDValue Load; 4817 if (ExtType == ISD::NON_EXTLOAD) 4818 Load = DAG.getLoad(VT, N0.getDebugLoc(), LN0->getChain(), NewPtr, 4819 LN0->getPointerInfo().getWithOffset(PtrOff), 4820 LN0->isVolatile(), LN0->isNonTemporal(), 4821 LN0->isInvariant(), NewAlign); 4822 else 4823 Load = DAG.getExtLoad(ExtType, N0.getDebugLoc(), VT, LN0->getChain(),NewPtr, 4824 LN0->getPointerInfo().getWithOffset(PtrOff), 4825 ExtVT, LN0->isVolatile(), LN0->isNonTemporal(), 4826 NewAlign); 4827 4828 // Replace the old load's chain with the new load's chain. 4829 WorkListRemover DeadNodes(*this); 4830 DAG.ReplaceAllUsesOfValueWith(N0.getValue(1), Load.getValue(1), 4831 &DeadNodes); 4832 4833 // Shift the result left, if we've swallowed a left shift. 4834 SDValue Result = Load; 4835 if (ShLeftAmt != 0) { 4836 EVT ShImmTy = getShiftAmountTy(Result.getValueType()); 4837 if (!isUIntN(ShImmTy.getSizeInBits(), ShLeftAmt)) 4838 ShImmTy = VT; 4839 Result = DAG.getNode(ISD::SHL, N0.getDebugLoc(), VT, 4840 Result, DAG.getConstant(ShLeftAmt, ShImmTy)); 4841 } 4842 4843 // Return the new loaded value. 4844 return Result; 4845} 4846 4847SDValue DAGCombiner::visitSIGN_EXTEND_INREG(SDNode *N) { 4848 SDValue N0 = N->getOperand(0); 4849 SDValue N1 = N->getOperand(1); 4850 EVT VT = N->getValueType(0); 4851 EVT EVT = cast<VTSDNode>(N1)->getVT(); 4852 unsigned VTBits = VT.getScalarType().getSizeInBits(); 4853 unsigned EVTBits = EVT.getScalarType().getSizeInBits(); 4854 4855 // fold (sext_in_reg c1) -> c1 4856 if (isa<ConstantSDNode>(N0) || N0.getOpcode() == ISD::UNDEF) 4857 return DAG.getNode(ISD::SIGN_EXTEND_INREG, N->getDebugLoc(), VT, N0, N1); 4858 4859 // If the input is already sign extended, just drop the extension. 4860 if (DAG.ComputeNumSignBits(N0) >= VTBits-EVTBits+1) 4861 return N0; 4862 4863 // fold (sext_in_reg (sext_in_reg x, VT2), VT1) -> (sext_in_reg x, minVT) pt2 4864 if (N0.getOpcode() == ISD::SIGN_EXTEND_INREG && 4865 EVT.bitsLT(cast<VTSDNode>(N0.getOperand(1))->getVT())) { 4866 return DAG.getNode(ISD::SIGN_EXTEND_INREG, N->getDebugLoc(), VT, 4867 N0.getOperand(0), N1); 4868 } 4869 4870 // fold (sext_in_reg (sext x)) -> (sext x) 4871 // fold (sext_in_reg (aext x)) -> (sext x) 4872 // if x is small enough. 4873 if (N0.getOpcode() == ISD::SIGN_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND) { 4874 SDValue N00 = N0.getOperand(0); 4875 if (N00.getValueType().getScalarType().getSizeInBits() <= EVTBits && 4876 (!LegalOperations || TLI.isOperationLegal(ISD::SIGN_EXTEND, VT))) 4877 return DAG.getNode(ISD::SIGN_EXTEND, N->getDebugLoc(), VT, N00, N1); 4878 } 4879 4880 // fold (sext_in_reg x) -> (zext_in_reg x) if the sign bit is known zero. 4881 if (DAG.MaskedValueIsZero(N0, APInt::getBitsSet(VTBits, EVTBits-1, EVTBits))) 4882 return DAG.getZeroExtendInReg(N0, N->getDebugLoc(), EVT); 4883 4884 // fold operands of sext_in_reg based on knowledge that the top bits are not 4885 // demanded. 4886 if (SimplifyDemandedBits(SDValue(N, 0))) 4887 return SDValue(N, 0); 4888 4889 // fold (sext_in_reg (load x)) -> (smaller sextload x) 4890 // fold (sext_in_reg (srl (load x), c)) -> (smaller sextload (x+c/evtbits)) 4891 SDValue NarrowLoad = ReduceLoadWidth(N); 4892 if (NarrowLoad.getNode()) 4893 return NarrowLoad; 4894 4895 // fold (sext_in_reg (srl X, 24), i8) -> (sra X, 24) 4896 // fold (sext_in_reg (srl X, 23), i8) -> (sra X, 23) iff possible. 4897 // We already fold "(sext_in_reg (srl X, 25), i8) -> srl X, 25" above. 4898 if (N0.getOpcode() == ISD::SRL) { 4899 if (ConstantSDNode *ShAmt = dyn_cast<ConstantSDNode>(N0.getOperand(1))) 4900 if (ShAmt->getZExtValue()+EVTBits <= VTBits) { 4901 // We can turn this into an SRA iff the input to the SRL is already sign 4902 // extended enough. 4903 unsigned InSignBits = DAG.ComputeNumSignBits(N0.getOperand(0)); 4904 if (VTBits-(ShAmt->getZExtValue()+EVTBits) < InSignBits) 4905 return DAG.getNode(ISD::SRA, N->getDebugLoc(), VT, 4906 N0.getOperand(0), N0.getOperand(1)); 4907 } 4908 } 4909 4910 // fold (sext_inreg (extload x)) -> (sextload x) 4911 if (ISD::isEXTLoad(N0.getNode()) && 4912 ISD::isUNINDEXEDLoad(N0.getNode()) && 4913 EVT == cast<LoadSDNode>(N0)->getMemoryVT() && 4914 ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) || 4915 TLI.isLoadExtLegal(ISD::SEXTLOAD, EVT))) { 4916 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 4917 SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, N->getDebugLoc(), VT, 4918 LN0->getChain(), 4919 LN0->getBasePtr(), LN0->getPointerInfo(), 4920 EVT, 4921 LN0->isVolatile(), LN0->isNonTemporal(), 4922 LN0->getAlignment()); 4923 CombineTo(N, ExtLoad); 4924 CombineTo(N0.getNode(), ExtLoad, ExtLoad.getValue(1)); 4925 return SDValue(N, 0); // Return N so it doesn't get rechecked! 4926 } 4927 // fold (sext_inreg (zextload x)) -> (sextload x) iff load has one use 4928 if (ISD::isZEXTLoad(N0.getNode()) && ISD::isUNINDEXEDLoad(N0.getNode()) && 4929 N0.hasOneUse() && 4930 EVT == cast<LoadSDNode>(N0)->getMemoryVT() && 4931 ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) || 4932 TLI.isLoadExtLegal(ISD::SEXTLOAD, EVT))) { 4933 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 4934 SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, N->getDebugLoc(), VT, 4935 LN0->getChain(), 4936 LN0->getBasePtr(), LN0->getPointerInfo(), 4937 EVT, 4938 LN0->isVolatile(), LN0->isNonTemporal(), 4939 LN0->getAlignment()); 4940 CombineTo(N, ExtLoad); 4941 CombineTo(N0.getNode(), ExtLoad, ExtLoad.getValue(1)); 4942 return SDValue(N, 0); // Return N so it doesn't get rechecked! 4943 } 4944 4945 // Form (sext_inreg (bswap >> 16)) or (sext_inreg (rotl (bswap) 16)) 4946 if (EVTBits <= 16 && N0.getOpcode() == ISD::OR) { 4947 SDValue BSwap = MatchBSwapHWordLow(N0.getNode(), N0.getOperand(0), 4948 N0.getOperand(1), false); 4949 if (BSwap.getNode() != 0) 4950 return DAG.getNode(ISD::SIGN_EXTEND_INREG, N->getDebugLoc(), VT, 4951 BSwap, N1); 4952 } 4953 4954 return SDValue(); 4955} 4956 4957SDValue DAGCombiner::visitTRUNCATE(SDNode *N) { 4958 SDValue N0 = N->getOperand(0); 4959 EVT VT = N->getValueType(0); 4960 4961 // noop truncate 4962 if (N0.getValueType() == N->getValueType(0)) 4963 return N0; 4964 // fold (truncate c1) -> c1 4965 if (isa<ConstantSDNode>(N0)) 4966 return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, N0); 4967 // fold (truncate (truncate x)) -> (truncate x) 4968 if (N0.getOpcode() == ISD::TRUNCATE) 4969 return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, N0.getOperand(0)); 4970 // fold (truncate (ext x)) -> (ext x) or (truncate x) or x 4971 if (N0.getOpcode() == ISD::ZERO_EXTEND || 4972 N0.getOpcode() == ISD::SIGN_EXTEND || 4973 N0.getOpcode() == ISD::ANY_EXTEND) { 4974 if (N0.getOperand(0).getValueType().bitsLT(VT)) 4975 // if the source is smaller than the dest, we still need an extend 4976 return DAG.getNode(N0.getOpcode(), N->getDebugLoc(), VT, 4977 N0.getOperand(0)); 4978 else if (N0.getOperand(0).getValueType().bitsGT(VT)) 4979 // if the source is larger than the dest, than we just need the truncate 4980 return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, N0.getOperand(0)); 4981 else 4982 // if the source and dest are the same type, we can drop both the extend 4983 // and the truncate. 4984 return N0.getOperand(0); 4985 } 4986 4987 // See if we can simplify the input to this truncate through knowledge that 4988 // only the low bits are being used. 4989 // For example "trunc (or (shl x, 8), y)" // -> trunc y 4990 // Currently we only perform this optimization on scalars because vectors 4991 // may have different active low bits. 4992 if (!VT.isVector()) { 4993 SDValue Shorter = 4994 GetDemandedBits(N0, APInt::getLowBitsSet(N0.getValueSizeInBits(), 4995 VT.getSizeInBits())); 4996 if (Shorter.getNode()) 4997 return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, Shorter); 4998 } 4999 // fold (truncate (load x)) -> (smaller load x) 5000 // fold (truncate (srl (load x), c)) -> (smaller load (x+c/evtbits)) 5001 if (!LegalTypes || TLI.isTypeDesirableForOp(N0.getOpcode(), VT)) { 5002 SDValue Reduced = ReduceLoadWidth(N); 5003 if (Reduced.getNode()) 5004 return Reduced; 5005 } 5006 5007 // Simplify the operands using demanded-bits information. 5008 if (!VT.isVector() && 5009 SimplifyDemandedBits(SDValue(N, 0))) 5010 return SDValue(N, 0); 5011 5012 return SDValue(); 5013} 5014 5015static SDNode *getBuildPairElt(SDNode *N, unsigned i) { 5016 SDValue Elt = N->getOperand(i); 5017 if (Elt.getOpcode() != ISD::MERGE_VALUES) 5018 return Elt.getNode(); 5019 return Elt.getOperand(Elt.getResNo()).getNode(); 5020} 5021 5022/// CombineConsecutiveLoads - build_pair (load, load) -> load 5023/// if load locations are consecutive. 5024SDValue DAGCombiner::CombineConsecutiveLoads(SDNode *N, EVT VT) { 5025 assert(N->getOpcode() == ISD::BUILD_PAIR); 5026 5027 LoadSDNode *LD1 = dyn_cast<LoadSDNode>(getBuildPairElt(N, 0)); 5028 LoadSDNode *LD2 = dyn_cast<LoadSDNode>(getBuildPairElt(N, 1)); 5029 if (!LD1 || !LD2 || !ISD::isNON_EXTLoad(LD1) || !LD1->hasOneUse() || 5030 LD1->getPointerInfo().getAddrSpace() != 5031 LD2->getPointerInfo().getAddrSpace()) 5032 return SDValue(); 5033 EVT LD1VT = LD1->getValueType(0); 5034 5035 if (ISD::isNON_EXTLoad(LD2) && 5036 LD2->hasOneUse() && 5037 // If both are volatile this would reduce the number of volatile loads. 5038 // If one is volatile it might be ok, but play conservative and bail out. 5039 !LD1->isVolatile() && 5040 !LD2->isVolatile() && 5041 DAG.isConsecutiveLoad(LD2, LD1, LD1VT.getSizeInBits()/8, 1)) { 5042 unsigned Align = LD1->getAlignment(); 5043 unsigned NewAlign = TLI.getTargetData()-> 5044 getABITypeAlignment(VT.getTypeForEVT(*DAG.getContext())); 5045 5046 if (NewAlign <= Align && 5047 (!LegalOperations || TLI.isOperationLegal(ISD::LOAD, VT))) 5048 return DAG.getLoad(VT, N->getDebugLoc(), LD1->getChain(), 5049 LD1->getBasePtr(), LD1->getPointerInfo(), 5050 false, false, false, Align); 5051 } 5052 5053 return SDValue(); 5054} 5055 5056SDValue DAGCombiner::visitBITCAST(SDNode *N) { 5057 SDValue N0 = N->getOperand(0); 5058 EVT VT = N->getValueType(0); 5059 5060 // If the input is a BUILD_VECTOR with all constant elements, fold this now. 5061 // Only do this before legalize, since afterward the target may be depending 5062 // on the bitconvert. 5063 // First check to see if this is all constant. 5064 if (!LegalTypes && 5065 N0.getOpcode() == ISD::BUILD_VECTOR && N0.getNode()->hasOneUse() && 5066 VT.isVector()) { 5067 bool isSimple = true; 5068 for (unsigned i = 0, e = N0.getNumOperands(); i != e; ++i) 5069 if (N0.getOperand(i).getOpcode() != ISD::UNDEF && 5070 N0.getOperand(i).getOpcode() != ISD::Constant && 5071 N0.getOperand(i).getOpcode() != ISD::ConstantFP) { 5072 isSimple = false; 5073 break; 5074 } 5075 5076 EVT DestEltVT = N->getValueType(0).getVectorElementType(); 5077 assert(!DestEltVT.isVector() && 5078 "Element type of vector ValueType must not be vector!"); 5079 if (isSimple) 5080 return ConstantFoldBITCASTofBUILD_VECTOR(N0.getNode(), DestEltVT); 5081 } 5082 5083 // If the input is a constant, let getNode fold it. 5084 if (isa<ConstantSDNode>(N0) || isa<ConstantFPSDNode>(N0)) { 5085 SDValue Res = DAG.getNode(ISD::BITCAST, N->getDebugLoc(), VT, N0); 5086 if (Res.getNode() != N) { 5087 if (!LegalOperations || 5088 TLI.isOperationLegal(Res.getNode()->getOpcode(), VT)) 5089 return Res; 5090 5091 // Folding it resulted in an illegal node, and it's too late to 5092 // do that. Clean up the old node and forego the transformation. 5093 // Ideally this won't happen very often, because instcombine 5094 // and the earlier dagcombine runs (where illegal nodes are 5095 // permitted) should have folded most of them already. 5096 DAG.DeleteNode(Res.getNode()); 5097 } 5098 } 5099 5100 // (conv (conv x, t1), t2) -> (conv x, t2) 5101 if (N0.getOpcode() == ISD::BITCAST) 5102 return DAG.getNode(ISD::BITCAST, N->getDebugLoc(), VT, 5103 N0.getOperand(0)); 5104 5105 // fold (conv (load x)) -> (load (conv*)x) 5106 // If the resultant load doesn't need a higher alignment than the original! 5107 if (ISD::isNormalLoad(N0.getNode()) && N0.hasOneUse() && 5108 // Do not change the width of a volatile load. 5109 !cast<LoadSDNode>(N0)->isVolatile() && 5110 (!LegalOperations || TLI.isOperationLegal(ISD::LOAD, VT))) { 5111 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 5112 unsigned Align = TLI.getTargetData()-> 5113 getABITypeAlignment(VT.getTypeForEVT(*DAG.getContext())); 5114 unsigned OrigAlign = LN0->getAlignment(); 5115 5116 if (Align <= OrigAlign) { 5117 SDValue Load = DAG.getLoad(VT, N->getDebugLoc(), LN0->getChain(), 5118 LN0->getBasePtr(), LN0->getPointerInfo(), 5119 LN0->isVolatile(), LN0->isNonTemporal(), 5120 LN0->isInvariant(), OrigAlign); 5121 AddToWorkList(N); 5122 CombineTo(N0.getNode(), 5123 DAG.getNode(ISD::BITCAST, N0.getDebugLoc(), 5124 N0.getValueType(), Load), 5125 Load.getValue(1)); 5126 return Load; 5127 } 5128 } 5129 5130 // fold (bitconvert (fneg x)) -> (xor (bitconvert x), signbit) 5131 // fold (bitconvert (fabs x)) -> (and (bitconvert x), (not signbit)) 5132 // This often reduces constant pool loads. 5133 if ((N0.getOpcode() == ISD::FNEG || N0.getOpcode() == ISD::FABS) && 5134 N0.getNode()->hasOneUse() && VT.isInteger() && !VT.isVector()) { 5135 SDValue NewConv = DAG.getNode(ISD::BITCAST, N0.getDebugLoc(), VT, 5136 N0.getOperand(0)); 5137 AddToWorkList(NewConv.getNode()); 5138 5139 APInt SignBit = APInt::getSignBit(VT.getSizeInBits()); 5140 if (N0.getOpcode() == ISD::FNEG) 5141 return DAG.getNode(ISD::XOR, N->getDebugLoc(), VT, 5142 NewConv, DAG.getConstant(SignBit, VT)); 5143 assert(N0.getOpcode() == ISD::FABS); 5144 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, 5145 NewConv, DAG.getConstant(~SignBit, VT)); 5146 } 5147 5148 // fold (bitconvert (fcopysign cst, x)) -> 5149 // (or (and (bitconvert x), sign), (and cst, (not sign))) 5150 // Note that we don't handle (copysign x, cst) because this can always be 5151 // folded to an fneg or fabs. 5152 if (N0.getOpcode() == ISD::FCOPYSIGN && N0.getNode()->hasOneUse() && 5153 isa<ConstantFPSDNode>(N0.getOperand(0)) && 5154 VT.isInteger() && !VT.isVector()) { 5155 unsigned OrigXWidth = N0.getOperand(1).getValueType().getSizeInBits(); 5156 EVT IntXVT = EVT::getIntegerVT(*DAG.getContext(), OrigXWidth); 5157 if (isTypeLegal(IntXVT)) { 5158 SDValue X = DAG.getNode(ISD::BITCAST, N0.getDebugLoc(), 5159 IntXVT, N0.getOperand(1)); 5160 AddToWorkList(X.getNode()); 5161 5162 // If X has a different width than the result/lhs, sext it or truncate it. 5163 unsigned VTWidth = VT.getSizeInBits(); 5164 if (OrigXWidth < VTWidth) { 5165 X = DAG.getNode(ISD::SIGN_EXTEND, N->getDebugLoc(), VT, X); 5166 AddToWorkList(X.getNode()); 5167 } else if (OrigXWidth > VTWidth) { 5168 // To get the sign bit in the right place, we have to shift it right 5169 // before truncating. 5170 X = DAG.getNode(ISD::SRL, X.getDebugLoc(), 5171 X.getValueType(), X, 5172 DAG.getConstant(OrigXWidth-VTWidth, X.getValueType())); 5173 AddToWorkList(X.getNode()); 5174 X = DAG.getNode(ISD::TRUNCATE, X.getDebugLoc(), VT, X); 5175 AddToWorkList(X.getNode()); 5176 } 5177 5178 APInt SignBit = APInt::getSignBit(VT.getSizeInBits()); 5179 X = DAG.getNode(ISD::AND, X.getDebugLoc(), VT, 5180 X, DAG.getConstant(SignBit, VT)); 5181 AddToWorkList(X.getNode()); 5182 5183 SDValue Cst = DAG.getNode(ISD::BITCAST, N0.getDebugLoc(), 5184 VT, N0.getOperand(0)); 5185 Cst = DAG.getNode(ISD::AND, Cst.getDebugLoc(), VT, 5186 Cst, DAG.getConstant(~SignBit, VT)); 5187 AddToWorkList(Cst.getNode()); 5188 5189 return DAG.getNode(ISD::OR, N->getDebugLoc(), VT, X, Cst); 5190 } 5191 } 5192 5193 // bitconvert(build_pair(ld, ld)) -> ld iff load locations are consecutive. 5194 if (N0.getOpcode() == ISD::BUILD_PAIR) { 5195 SDValue CombineLD = CombineConsecutiveLoads(N0.getNode(), VT); 5196 if (CombineLD.getNode()) 5197 return CombineLD; 5198 } 5199 5200 return SDValue(); 5201} 5202 5203SDValue DAGCombiner::visitBUILD_PAIR(SDNode *N) { 5204 EVT VT = N->getValueType(0); 5205 return CombineConsecutiveLoads(N, VT); 5206} 5207 5208/// ConstantFoldBITCASTofBUILD_VECTOR - We know that BV is a build_vector 5209/// node with Constant, ConstantFP or Undef operands. DstEltVT indicates the 5210/// destination element value type. 5211SDValue DAGCombiner:: 5212ConstantFoldBITCASTofBUILD_VECTOR(SDNode *BV, EVT DstEltVT) { 5213 EVT SrcEltVT = BV->getValueType(0).getVectorElementType(); 5214 5215 // If this is already the right type, we're done. 5216 if (SrcEltVT == DstEltVT) return SDValue(BV, 0); 5217 5218 unsigned SrcBitSize = SrcEltVT.getSizeInBits(); 5219 unsigned DstBitSize = DstEltVT.getSizeInBits(); 5220 5221 // If this is a conversion of N elements of one type to N elements of another 5222 // type, convert each element. This handles FP<->INT cases. 5223 if (SrcBitSize == DstBitSize) { 5224 EVT VT = EVT::getVectorVT(*DAG.getContext(), DstEltVT, 5225 BV->getValueType(0).getVectorNumElements()); 5226 5227 // Due to the FP element handling below calling this routine recursively, 5228 // we can end up with a scalar-to-vector node here. 5229 if (BV->getOpcode() == ISD::SCALAR_TO_VECTOR) 5230 return DAG.getNode(ISD::SCALAR_TO_VECTOR, BV->getDebugLoc(), VT, 5231 DAG.getNode(ISD::BITCAST, BV->getDebugLoc(), 5232 DstEltVT, BV->getOperand(0))); 5233 5234 SmallVector<SDValue, 8> Ops; 5235 for (unsigned i = 0, e = BV->getNumOperands(); i != e; ++i) { 5236 SDValue Op = BV->getOperand(i); 5237 // If the vector element type is not legal, the BUILD_VECTOR operands 5238 // are promoted and implicitly truncated. Make that explicit here. 5239 if (Op.getValueType() != SrcEltVT) 5240 Op = DAG.getNode(ISD::TRUNCATE, BV->getDebugLoc(), SrcEltVT, Op); 5241 Ops.push_back(DAG.getNode(ISD::BITCAST, BV->getDebugLoc(), 5242 DstEltVT, Op)); 5243 AddToWorkList(Ops.back().getNode()); 5244 } 5245 return DAG.getNode(ISD::BUILD_VECTOR, BV->getDebugLoc(), VT, 5246 &Ops[0], Ops.size()); 5247 } 5248 5249 // Otherwise, we're growing or shrinking the elements. To avoid having to 5250 // handle annoying details of growing/shrinking FP values, we convert them to 5251 // int first. 5252 if (SrcEltVT.isFloatingPoint()) { 5253 // Convert the input float vector to a int vector where the elements are the 5254 // same sizes. 5255 assert((SrcEltVT == MVT::f32 || SrcEltVT == MVT::f64) && "Unknown FP VT!"); 5256 EVT IntVT = EVT::getIntegerVT(*DAG.getContext(), SrcEltVT.getSizeInBits()); 5257 BV = ConstantFoldBITCASTofBUILD_VECTOR(BV, IntVT).getNode(); 5258 SrcEltVT = IntVT; 5259 } 5260 5261 // Now we know the input is an integer vector. If the output is a FP type, 5262 // convert to integer first, then to FP of the right size. 5263 if (DstEltVT.isFloatingPoint()) { 5264 assert((DstEltVT == MVT::f32 || DstEltVT == MVT::f64) && "Unknown FP VT!"); 5265 EVT TmpVT = EVT::getIntegerVT(*DAG.getContext(), DstEltVT.getSizeInBits()); 5266 SDNode *Tmp = ConstantFoldBITCASTofBUILD_VECTOR(BV, TmpVT).getNode(); 5267 5268 // Next, convert to FP elements of the same size. 5269 return ConstantFoldBITCASTofBUILD_VECTOR(Tmp, DstEltVT); 5270 } 5271 5272 // Okay, we know the src/dst types are both integers of differing types. 5273 // Handling growing first. 5274 assert(SrcEltVT.isInteger() && DstEltVT.isInteger()); 5275 if (SrcBitSize < DstBitSize) { 5276 unsigned NumInputsPerOutput = DstBitSize/SrcBitSize; 5277 5278 SmallVector<SDValue, 8> Ops; 5279 for (unsigned i = 0, e = BV->getNumOperands(); i != e; 5280 i += NumInputsPerOutput) { 5281 bool isLE = TLI.isLittleEndian(); 5282 APInt NewBits = APInt(DstBitSize, 0); 5283 bool EltIsUndef = true; 5284 for (unsigned j = 0; j != NumInputsPerOutput; ++j) { 5285 // Shift the previously computed bits over. 5286 NewBits <<= SrcBitSize; 5287 SDValue Op = BV->getOperand(i+ (isLE ? (NumInputsPerOutput-j-1) : j)); 5288 if (Op.getOpcode() == ISD::UNDEF) continue; 5289 EltIsUndef = false; 5290 5291 NewBits |= cast<ConstantSDNode>(Op)->getAPIntValue(). 5292 zextOrTrunc(SrcBitSize).zext(DstBitSize); 5293 } 5294 5295 if (EltIsUndef) 5296 Ops.push_back(DAG.getUNDEF(DstEltVT)); 5297 else 5298 Ops.push_back(DAG.getConstant(NewBits, DstEltVT)); 5299 } 5300 5301 EVT VT = EVT::getVectorVT(*DAG.getContext(), DstEltVT, Ops.size()); 5302 return DAG.getNode(ISD::BUILD_VECTOR, BV->getDebugLoc(), VT, 5303 &Ops[0], Ops.size()); 5304 } 5305 5306 // Finally, this must be the case where we are shrinking elements: each input 5307 // turns into multiple outputs. 5308 bool isS2V = ISD::isScalarToVector(BV); 5309 unsigned NumOutputsPerInput = SrcBitSize/DstBitSize; 5310 EVT VT = EVT::getVectorVT(*DAG.getContext(), DstEltVT, 5311 NumOutputsPerInput*BV->getNumOperands()); 5312 SmallVector<SDValue, 8> Ops; 5313 5314 for (unsigned i = 0, e = BV->getNumOperands(); i != e; ++i) { 5315 if (BV->getOperand(i).getOpcode() == ISD::UNDEF) { 5316 for (unsigned j = 0; j != NumOutputsPerInput; ++j) 5317 Ops.push_back(DAG.getUNDEF(DstEltVT)); 5318 continue; 5319 } 5320 5321 APInt OpVal = cast<ConstantSDNode>(BV->getOperand(i))-> 5322 getAPIntValue().zextOrTrunc(SrcBitSize); 5323 5324 for (unsigned j = 0; j != NumOutputsPerInput; ++j) { 5325 APInt ThisVal = OpVal.trunc(DstBitSize); 5326 Ops.push_back(DAG.getConstant(ThisVal, DstEltVT)); 5327 if (isS2V && i == 0 && j == 0 && ThisVal.zext(SrcBitSize) == OpVal) 5328 // Simply turn this into a SCALAR_TO_VECTOR of the new type. 5329 return DAG.getNode(ISD::SCALAR_TO_VECTOR, BV->getDebugLoc(), VT, 5330 Ops[0]); 5331 OpVal = OpVal.lshr(DstBitSize); 5332 } 5333 5334 // For big endian targets, swap the order of the pieces of each element. 5335 if (TLI.isBigEndian()) 5336 std::reverse(Ops.end()-NumOutputsPerInput, Ops.end()); 5337 } 5338 5339 return DAG.getNode(ISD::BUILD_VECTOR, BV->getDebugLoc(), VT, 5340 &Ops[0], Ops.size()); 5341} 5342 5343SDValue DAGCombiner::visitFADD(SDNode *N) { 5344 SDValue N0 = N->getOperand(0); 5345 SDValue N1 = N->getOperand(1); 5346 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 5347 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1); 5348 EVT VT = N->getValueType(0); 5349 5350 // fold vector ops 5351 if (VT.isVector()) { 5352 SDValue FoldedVOp = SimplifyVBinOp(N); 5353 if (FoldedVOp.getNode()) return FoldedVOp; 5354 } 5355 5356 // fold (fadd c1, c2) -> (fadd c1, c2) 5357 if (N0CFP && N1CFP && VT != MVT::ppcf128) 5358 return DAG.getNode(ISD::FADD, N->getDebugLoc(), VT, N0, N1); 5359 // canonicalize constant to RHS 5360 if (N0CFP && !N1CFP) 5361 return DAG.getNode(ISD::FADD, N->getDebugLoc(), VT, N1, N0); 5362 // fold (fadd A, 0) -> A 5363 if (DAG.getTarget().Options.UnsafeFPMath && N1CFP && 5364 N1CFP->getValueAPF().isZero()) 5365 return N0; 5366 // fold (fadd A, (fneg B)) -> (fsub A, B) 5367 if (isNegatibleForFree(N1, LegalOperations, &DAG.getTarget().Options) == 2) 5368 return DAG.getNode(ISD::FSUB, N->getDebugLoc(), VT, N0, 5369 GetNegatedExpression(N1, DAG, LegalOperations)); 5370 // fold (fadd (fneg A), B) -> (fsub B, A) 5371 if (isNegatibleForFree(N0, LegalOperations, &DAG.getTarget().Options) == 2) 5372 return DAG.getNode(ISD::FSUB, N->getDebugLoc(), VT, N1, 5373 GetNegatedExpression(N0, DAG, LegalOperations)); 5374 5375 // If allowed, fold (fadd (fadd x, c1), c2) -> (fadd x, (fadd c1, c2)) 5376 if (DAG.getTarget().Options.UnsafeFPMath && N1CFP && 5377 N0.getOpcode() == ISD::FADD && N0.getNode()->hasOneUse() && 5378 isa<ConstantFPSDNode>(N0.getOperand(1))) 5379 return DAG.getNode(ISD::FADD, N->getDebugLoc(), VT, N0.getOperand(0), 5380 DAG.getNode(ISD::FADD, N->getDebugLoc(), VT, 5381 N0.getOperand(1), N1)); 5382 5383 return SDValue(); 5384} 5385 5386SDValue DAGCombiner::visitFSUB(SDNode *N) { 5387 SDValue N0 = N->getOperand(0); 5388 SDValue N1 = N->getOperand(1); 5389 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 5390 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1); 5391 EVT VT = N->getValueType(0); 5392 5393 // fold vector ops 5394 if (VT.isVector()) { 5395 SDValue FoldedVOp = SimplifyVBinOp(N); 5396 if (FoldedVOp.getNode()) return FoldedVOp; 5397 } 5398 5399 // fold (fsub c1, c2) -> c1-c2 5400 if (N0CFP && N1CFP && VT != MVT::ppcf128) 5401 return DAG.getNode(ISD::FSUB, N->getDebugLoc(), VT, N0, N1); 5402 // fold (fsub A, 0) -> A 5403 if (DAG.getTarget().Options.UnsafeFPMath && 5404 N1CFP && N1CFP->getValueAPF().isZero()) 5405 return N0; 5406 // fold (fsub 0, B) -> -B 5407 if (DAG.getTarget().Options.UnsafeFPMath && 5408 N0CFP && N0CFP->getValueAPF().isZero()) { 5409 if (isNegatibleForFree(N1, LegalOperations, &DAG.getTarget().Options)) 5410 return GetNegatedExpression(N1, DAG, LegalOperations); 5411 if (!LegalOperations || TLI.isOperationLegal(ISD::FNEG, VT)) 5412 return DAG.getNode(ISD::FNEG, N->getDebugLoc(), VT, N1); 5413 } 5414 // fold (fsub A, (fneg B)) -> (fadd A, B) 5415 if (isNegatibleForFree(N1, LegalOperations, &DAG.getTarget().Options)) 5416 return DAG.getNode(ISD::FADD, N->getDebugLoc(), VT, N0, 5417 GetNegatedExpression(N1, DAG, LegalOperations)); 5418 5419 return SDValue(); 5420} 5421 5422SDValue DAGCombiner::visitFMUL(SDNode *N) { 5423 SDValue N0 = N->getOperand(0); 5424 SDValue N1 = N->getOperand(1); 5425 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 5426 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1); 5427 EVT VT = N->getValueType(0); 5428 5429 // fold vector ops 5430 if (VT.isVector()) { 5431 SDValue FoldedVOp = SimplifyVBinOp(N); 5432 if (FoldedVOp.getNode()) return FoldedVOp; 5433 } 5434 5435 // fold (fmul c1, c2) -> c1*c2 5436 if (N0CFP && N1CFP && VT != MVT::ppcf128) 5437 return DAG.getNode(ISD::FMUL, N->getDebugLoc(), VT, N0, N1); 5438 // canonicalize constant to RHS 5439 if (N0CFP && !N1CFP) 5440 return DAG.getNode(ISD::FMUL, N->getDebugLoc(), VT, N1, N0); 5441 // fold (fmul A, 0) -> 0 5442 if (DAG.getTarget().Options.UnsafeFPMath && 5443 N1CFP && N1CFP->getValueAPF().isZero()) 5444 return N1; 5445 // fold (fmul A, 0) -> 0, vector edition. 5446 if (DAG.getTarget().Options.UnsafeFPMath && 5447 ISD::isBuildVectorAllZeros(N1.getNode())) 5448 return N1; 5449 // fold (fmul X, 2.0) -> (fadd X, X) 5450 if (N1CFP && N1CFP->isExactlyValue(+2.0)) 5451 return DAG.getNode(ISD::FADD, N->getDebugLoc(), VT, N0, N0); 5452 // fold (fmul X, -1.0) -> (fneg X) 5453 if (N1CFP && N1CFP->isExactlyValue(-1.0)) 5454 if (!LegalOperations || TLI.isOperationLegal(ISD::FNEG, VT)) 5455 return DAG.getNode(ISD::FNEG, N->getDebugLoc(), VT, N0); 5456 5457 // fold (fmul (fneg X), (fneg Y)) -> (fmul X, Y) 5458 if (char LHSNeg = isNegatibleForFree(N0, LegalOperations, 5459 &DAG.getTarget().Options)) { 5460 if (char RHSNeg = isNegatibleForFree(N1, LegalOperations, 5461 &DAG.getTarget().Options)) { 5462 // Both can be negated for free, check to see if at least one is cheaper 5463 // negated. 5464 if (LHSNeg == 2 || RHSNeg == 2) 5465 return DAG.getNode(ISD::FMUL, N->getDebugLoc(), VT, 5466 GetNegatedExpression(N0, DAG, LegalOperations), 5467 GetNegatedExpression(N1, DAG, LegalOperations)); 5468 } 5469 } 5470 5471 // If allowed, fold (fmul (fmul x, c1), c2) -> (fmul x, (fmul c1, c2)) 5472 if (DAG.getTarget().Options.UnsafeFPMath && 5473 N1CFP && N0.getOpcode() == ISD::FMUL && 5474 N0.getNode()->hasOneUse() && isa<ConstantFPSDNode>(N0.getOperand(1))) 5475 return DAG.getNode(ISD::FMUL, N->getDebugLoc(), VT, N0.getOperand(0), 5476 DAG.getNode(ISD::FMUL, N->getDebugLoc(), VT, 5477 N0.getOperand(1), N1)); 5478 5479 return SDValue(); 5480} 5481 5482SDValue DAGCombiner::visitFDIV(SDNode *N) { 5483 SDValue N0 = N->getOperand(0); 5484 SDValue N1 = N->getOperand(1); 5485 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 5486 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1); 5487 EVT VT = N->getValueType(0); 5488 5489 // fold vector ops 5490 if (VT.isVector()) { 5491 SDValue FoldedVOp = SimplifyVBinOp(N); 5492 if (FoldedVOp.getNode()) return FoldedVOp; 5493 } 5494 5495 // fold (fdiv c1, c2) -> c1/c2 5496 if (N0CFP && N1CFP && VT != MVT::ppcf128) 5497 return DAG.getNode(ISD::FDIV, N->getDebugLoc(), VT, N0, N1); 5498 5499 5500 // (fdiv (fneg X), (fneg Y)) -> (fdiv X, Y) 5501 if (char LHSNeg = isNegatibleForFree(N0, LegalOperations, 5502 &DAG.getTarget().Options)) { 5503 if (char RHSNeg = isNegatibleForFree(N1, LegalOperations, 5504 &DAG.getTarget().Options)) { 5505 // Both can be negated for free, check to see if at least one is cheaper 5506 // negated. 5507 if (LHSNeg == 2 || RHSNeg == 2) 5508 return DAG.getNode(ISD::FDIV, N->getDebugLoc(), VT, 5509 GetNegatedExpression(N0, DAG, LegalOperations), 5510 GetNegatedExpression(N1, DAG, LegalOperations)); 5511 } 5512 } 5513 5514 return SDValue(); 5515} 5516 5517SDValue DAGCombiner::visitFREM(SDNode *N) { 5518 SDValue N0 = N->getOperand(0); 5519 SDValue N1 = N->getOperand(1); 5520 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 5521 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1); 5522 EVT VT = N->getValueType(0); 5523 5524 // fold (frem c1, c2) -> fmod(c1,c2) 5525 if (N0CFP && N1CFP && VT != MVT::ppcf128) 5526 return DAG.getNode(ISD::FREM, N->getDebugLoc(), VT, N0, N1); 5527 5528 return SDValue(); 5529} 5530 5531SDValue DAGCombiner::visitFCOPYSIGN(SDNode *N) { 5532 SDValue N0 = N->getOperand(0); 5533 SDValue N1 = N->getOperand(1); 5534 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 5535 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1); 5536 EVT VT = N->getValueType(0); 5537 5538 if (N0CFP && N1CFP && VT != MVT::ppcf128) // Constant fold 5539 return DAG.getNode(ISD::FCOPYSIGN, N->getDebugLoc(), VT, N0, N1); 5540 5541 if (N1CFP) { 5542 const APFloat& V = N1CFP->getValueAPF(); 5543 // copysign(x, c1) -> fabs(x) iff ispos(c1) 5544 // copysign(x, c1) -> fneg(fabs(x)) iff isneg(c1) 5545 if (!V.isNegative()) { 5546 if (!LegalOperations || TLI.isOperationLegal(ISD::FABS, VT)) 5547 return DAG.getNode(ISD::FABS, N->getDebugLoc(), VT, N0); 5548 } else { 5549 if (!LegalOperations || TLI.isOperationLegal(ISD::FNEG, VT)) 5550 return DAG.getNode(ISD::FNEG, N->getDebugLoc(), VT, 5551 DAG.getNode(ISD::FABS, N0.getDebugLoc(), VT, N0)); 5552 } 5553 } 5554 5555 // copysign(fabs(x), y) -> copysign(x, y) 5556 // copysign(fneg(x), y) -> copysign(x, y) 5557 // copysign(copysign(x,z), y) -> copysign(x, y) 5558 if (N0.getOpcode() == ISD::FABS || N0.getOpcode() == ISD::FNEG || 5559 N0.getOpcode() == ISD::FCOPYSIGN) 5560 return DAG.getNode(ISD::FCOPYSIGN, N->getDebugLoc(), VT, 5561 N0.getOperand(0), N1); 5562 5563 // copysign(x, abs(y)) -> abs(x) 5564 if (N1.getOpcode() == ISD::FABS) 5565 return DAG.getNode(ISD::FABS, N->getDebugLoc(), VT, N0); 5566 5567 // copysign(x, copysign(y,z)) -> copysign(x, z) 5568 if (N1.getOpcode() == ISD::FCOPYSIGN) 5569 return DAG.getNode(ISD::FCOPYSIGN, N->getDebugLoc(), VT, 5570 N0, N1.getOperand(1)); 5571 5572 // copysign(x, fp_extend(y)) -> copysign(x, y) 5573 // copysign(x, fp_round(y)) -> copysign(x, y) 5574 if (N1.getOpcode() == ISD::FP_EXTEND || N1.getOpcode() == ISD::FP_ROUND) 5575 return DAG.getNode(ISD::FCOPYSIGN, N->getDebugLoc(), VT, 5576 N0, N1.getOperand(0)); 5577 5578 return SDValue(); 5579} 5580 5581SDValue DAGCombiner::visitSINT_TO_FP(SDNode *N) { 5582 SDValue N0 = N->getOperand(0); 5583 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 5584 EVT VT = N->getValueType(0); 5585 EVT OpVT = N0.getValueType(); 5586 5587 // fold (sint_to_fp c1) -> c1fp 5588 if (N0C && OpVT != MVT::ppcf128 && 5589 // ...but only if the target supports immediate floating-point values 5590 (!LegalOperations || 5591 TLI.isOperationLegalOrCustom(llvm::ISD::ConstantFP, VT))) 5592 return DAG.getNode(ISD::SINT_TO_FP, N->getDebugLoc(), VT, N0); 5593 5594 // If the input is a legal type, and SINT_TO_FP is not legal on this target, 5595 // but UINT_TO_FP is legal on this target, try to convert. 5596 if (!TLI.isOperationLegalOrCustom(ISD::SINT_TO_FP, OpVT) && 5597 TLI.isOperationLegalOrCustom(ISD::UINT_TO_FP, OpVT)) { 5598 // If the sign bit is known to be zero, we can change this to UINT_TO_FP. 5599 if (DAG.SignBitIsZero(N0)) 5600 return DAG.getNode(ISD::UINT_TO_FP, N->getDebugLoc(), VT, N0); 5601 } 5602 5603 return SDValue(); 5604} 5605 5606SDValue DAGCombiner::visitUINT_TO_FP(SDNode *N) { 5607 SDValue N0 = N->getOperand(0); 5608 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 5609 EVT VT = N->getValueType(0); 5610 EVT OpVT = N0.getValueType(); 5611 5612 // fold (uint_to_fp c1) -> c1fp 5613 if (N0C && OpVT != MVT::ppcf128 && 5614 // ...but only if the target supports immediate floating-point values 5615 (!LegalOperations || 5616 TLI.isOperationLegalOrCustom(llvm::ISD::ConstantFP, VT))) 5617 return DAG.getNode(ISD::UINT_TO_FP, N->getDebugLoc(), VT, N0); 5618 5619 // If the input is a legal type, and UINT_TO_FP is not legal on this target, 5620 // but SINT_TO_FP is legal on this target, try to convert. 5621 if (!TLI.isOperationLegalOrCustom(ISD::UINT_TO_FP, OpVT) && 5622 TLI.isOperationLegalOrCustom(ISD::SINT_TO_FP, OpVT)) { 5623 // If the sign bit is known to be zero, we can change this to SINT_TO_FP. 5624 if (DAG.SignBitIsZero(N0)) 5625 return DAG.getNode(ISD::SINT_TO_FP, N->getDebugLoc(), VT, N0); 5626 } 5627 5628 return SDValue(); 5629} 5630 5631SDValue DAGCombiner::visitFP_TO_SINT(SDNode *N) { 5632 SDValue N0 = N->getOperand(0); 5633 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 5634 EVT VT = N->getValueType(0); 5635 5636 // fold (fp_to_sint c1fp) -> c1 5637 if (N0CFP) 5638 return DAG.getNode(ISD::FP_TO_SINT, N->getDebugLoc(), VT, N0); 5639 5640 return SDValue(); 5641} 5642 5643SDValue DAGCombiner::visitFP_TO_UINT(SDNode *N) { 5644 SDValue N0 = N->getOperand(0); 5645 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 5646 EVT VT = N->getValueType(0); 5647 5648 // fold (fp_to_uint c1fp) -> c1 5649 if (N0CFP && VT != MVT::ppcf128) 5650 return DAG.getNode(ISD::FP_TO_UINT, N->getDebugLoc(), VT, N0); 5651 5652 return SDValue(); 5653} 5654 5655SDValue DAGCombiner::visitFP_ROUND(SDNode *N) { 5656 SDValue N0 = N->getOperand(0); 5657 SDValue N1 = N->getOperand(1); 5658 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 5659 EVT VT = N->getValueType(0); 5660 5661 // fold (fp_round c1fp) -> c1fp 5662 if (N0CFP && N0.getValueType() != MVT::ppcf128) 5663 return DAG.getNode(ISD::FP_ROUND, N->getDebugLoc(), VT, N0, N1); 5664 5665 // fold (fp_round (fp_extend x)) -> x 5666 if (N0.getOpcode() == ISD::FP_EXTEND && VT == N0.getOperand(0).getValueType()) 5667 return N0.getOperand(0); 5668 5669 // fold (fp_round (fp_round x)) -> (fp_round x) 5670 if (N0.getOpcode() == ISD::FP_ROUND) { 5671 // This is a value preserving truncation if both round's are. 5672 bool IsTrunc = N->getConstantOperandVal(1) == 1 && 5673 N0.getNode()->getConstantOperandVal(1) == 1; 5674 return DAG.getNode(ISD::FP_ROUND, N->getDebugLoc(), VT, N0.getOperand(0), 5675 DAG.getIntPtrConstant(IsTrunc)); 5676 } 5677 5678 // fold (fp_round (copysign X, Y)) -> (copysign (fp_round X), Y) 5679 if (N0.getOpcode() == ISD::FCOPYSIGN && N0.getNode()->hasOneUse()) { 5680 SDValue Tmp = DAG.getNode(ISD::FP_ROUND, N0.getDebugLoc(), VT, 5681 N0.getOperand(0), N1); 5682 AddToWorkList(Tmp.getNode()); 5683 return DAG.getNode(ISD::FCOPYSIGN, N->getDebugLoc(), VT, 5684 Tmp, N0.getOperand(1)); 5685 } 5686 5687 return SDValue(); 5688} 5689 5690SDValue DAGCombiner::visitFP_ROUND_INREG(SDNode *N) { 5691 SDValue N0 = N->getOperand(0); 5692 EVT VT = N->getValueType(0); 5693 EVT EVT = cast<VTSDNode>(N->getOperand(1))->getVT(); 5694 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 5695 5696 // fold (fp_round_inreg c1fp) -> c1fp 5697 if (N0CFP && isTypeLegal(EVT)) { 5698 SDValue Round = DAG.getConstantFP(*N0CFP->getConstantFPValue(), EVT); 5699 return DAG.getNode(ISD::FP_EXTEND, N->getDebugLoc(), VT, Round); 5700 } 5701 5702 return SDValue(); 5703} 5704 5705SDValue DAGCombiner::visitFP_EXTEND(SDNode *N) { 5706 SDValue N0 = N->getOperand(0); 5707 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 5708 EVT VT = N->getValueType(0); 5709 5710 // If this is fp_round(fpextend), don't fold it, allow ourselves to be folded. 5711 if (N->hasOneUse() && 5712 N->use_begin()->getOpcode() == ISD::FP_ROUND) 5713 return SDValue(); 5714 5715 // fold (fp_extend c1fp) -> c1fp 5716 if (N0CFP && VT != MVT::ppcf128) 5717 return DAG.getNode(ISD::FP_EXTEND, N->getDebugLoc(), VT, N0); 5718 5719 // Turn fp_extend(fp_round(X, 1)) -> x since the fp_round doesn't affect the 5720 // value of X. 5721 if (N0.getOpcode() == ISD::FP_ROUND 5722 && N0.getNode()->getConstantOperandVal(1) == 1) { 5723 SDValue In = N0.getOperand(0); 5724 if (In.getValueType() == VT) return In; 5725 if (VT.bitsLT(In.getValueType())) 5726 return DAG.getNode(ISD::FP_ROUND, N->getDebugLoc(), VT, 5727 In, N0.getOperand(1)); 5728 return DAG.getNode(ISD::FP_EXTEND, N->getDebugLoc(), VT, In); 5729 } 5730 5731 // fold (fpext (load x)) -> (fpext (fptrunc (extload x))) 5732 if (ISD::isNON_EXTLoad(N0.getNode()) && N0.hasOneUse() && 5733 ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) || 5734 TLI.isLoadExtLegal(ISD::EXTLOAD, N0.getValueType()))) { 5735 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 5736 SDValue ExtLoad = DAG.getExtLoad(ISD::EXTLOAD, N->getDebugLoc(), VT, 5737 LN0->getChain(), 5738 LN0->getBasePtr(), LN0->getPointerInfo(), 5739 N0.getValueType(), 5740 LN0->isVolatile(), LN0->isNonTemporal(), 5741 LN0->getAlignment()); 5742 CombineTo(N, ExtLoad); 5743 CombineTo(N0.getNode(), 5744 DAG.getNode(ISD::FP_ROUND, N0.getDebugLoc(), 5745 N0.getValueType(), ExtLoad, DAG.getIntPtrConstant(1)), 5746 ExtLoad.getValue(1)); 5747 return SDValue(N, 0); // Return N so it doesn't get rechecked! 5748 } 5749 5750 return SDValue(); 5751} 5752 5753SDValue DAGCombiner::visitFNEG(SDNode *N) { 5754 SDValue N0 = N->getOperand(0); 5755 EVT VT = N->getValueType(0); 5756 5757 if (isNegatibleForFree(N0, LegalOperations, &DAG.getTarget().Options)) 5758 return GetNegatedExpression(N0, DAG, LegalOperations); 5759 5760 // Transform fneg(bitconvert(x)) -> bitconvert(x^sign) to avoid loading 5761 // constant pool values. 5762 if (N0.getOpcode() == ISD::BITCAST && 5763 !VT.isVector() && 5764 N0.getNode()->hasOneUse() && 5765 N0.getOperand(0).getValueType().isInteger()) { 5766 SDValue Int = N0.getOperand(0); 5767 EVT IntVT = Int.getValueType(); 5768 if (IntVT.isInteger() && !IntVT.isVector()) { 5769 Int = DAG.getNode(ISD::XOR, N0.getDebugLoc(), IntVT, Int, 5770 DAG.getConstant(APInt::getSignBit(IntVT.getSizeInBits()), IntVT)); 5771 AddToWorkList(Int.getNode()); 5772 return DAG.getNode(ISD::BITCAST, N->getDebugLoc(), 5773 VT, Int); 5774 } 5775 } 5776 5777 return SDValue(); 5778} 5779 5780SDValue DAGCombiner::visitFABS(SDNode *N) { 5781 SDValue N0 = N->getOperand(0); 5782 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 5783 EVT VT = N->getValueType(0); 5784 5785 // fold (fabs c1) -> fabs(c1) 5786 if (N0CFP && VT != MVT::ppcf128) 5787 return DAG.getNode(ISD::FABS, N->getDebugLoc(), VT, N0); 5788 // fold (fabs (fabs x)) -> (fabs x) 5789 if (N0.getOpcode() == ISD::FABS) 5790 return N->getOperand(0); 5791 // fold (fabs (fneg x)) -> (fabs x) 5792 // fold (fabs (fcopysign x, y)) -> (fabs x) 5793 if (N0.getOpcode() == ISD::FNEG || N0.getOpcode() == ISD::FCOPYSIGN) 5794 return DAG.getNode(ISD::FABS, N->getDebugLoc(), VT, N0.getOperand(0)); 5795 5796 // Transform fabs(bitconvert(x)) -> bitconvert(x&~sign) to avoid loading 5797 // constant pool values. 5798 if (N0.getOpcode() == ISD::BITCAST && N0.getNode()->hasOneUse() && 5799 N0.getOperand(0).getValueType().isInteger() && 5800 !N0.getOperand(0).getValueType().isVector()) { 5801 SDValue Int = N0.getOperand(0); 5802 EVT IntVT = Int.getValueType(); 5803 if (IntVT.isInteger() && !IntVT.isVector()) { 5804 Int = DAG.getNode(ISD::AND, N0.getDebugLoc(), IntVT, Int, 5805 DAG.getConstant(~APInt::getSignBit(IntVT.getSizeInBits()), IntVT)); 5806 AddToWorkList(Int.getNode()); 5807 return DAG.getNode(ISD::BITCAST, N->getDebugLoc(), 5808 N->getValueType(0), Int); 5809 } 5810 } 5811 5812 return SDValue(); 5813} 5814 5815SDValue DAGCombiner::visitBRCOND(SDNode *N) { 5816 SDValue Chain = N->getOperand(0); 5817 SDValue N1 = N->getOperand(1); 5818 SDValue N2 = N->getOperand(2); 5819 5820 // If N is a constant we could fold this into a fallthrough or unconditional 5821 // branch. However that doesn't happen very often in normal code, because 5822 // Instcombine/SimplifyCFG should have handled the available opportunities. 5823 // If we did this folding here, it would be necessary to update the 5824 // MachineBasicBlock CFG, which is awkward. 5825 5826 // fold a brcond with a setcc condition into a BR_CC node if BR_CC is legal 5827 // on the target. 5828 if (N1.getOpcode() == ISD::SETCC && 5829 TLI.isOperationLegalOrCustom(ISD::BR_CC, MVT::Other)) { 5830 return DAG.getNode(ISD::BR_CC, N->getDebugLoc(), MVT::Other, 5831 Chain, N1.getOperand(2), 5832 N1.getOperand(0), N1.getOperand(1), N2); 5833 } 5834 5835 if ((N1.hasOneUse() && N1.getOpcode() == ISD::SRL) || 5836 ((N1.getOpcode() == ISD::TRUNCATE && N1.hasOneUse()) && 5837 (N1.getOperand(0).hasOneUse() && 5838 N1.getOperand(0).getOpcode() == ISD::SRL))) { 5839 SDNode *Trunc = 0; 5840 if (N1.getOpcode() == ISD::TRUNCATE) { 5841 // Look pass the truncate. 5842 Trunc = N1.getNode(); 5843 N1 = N1.getOperand(0); 5844 } 5845 5846 // Match this pattern so that we can generate simpler code: 5847 // 5848 // %a = ... 5849 // %b = and i32 %a, 2 5850 // %c = srl i32 %b, 1 5851 // brcond i32 %c ... 5852 // 5853 // into 5854 // 5855 // %a = ... 5856 // %b = and i32 %a, 2 5857 // %c = setcc eq %b, 0 5858 // brcond %c ... 5859 // 5860 // This applies only when the AND constant value has one bit set and the 5861 // SRL constant is equal to the log2 of the AND constant. The back-end is 5862 // smart enough to convert the result into a TEST/JMP sequence. 5863 SDValue Op0 = N1.getOperand(0); 5864 SDValue Op1 = N1.getOperand(1); 5865 5866 if (Op0.getOpcode() == ISD::AND && 5867 Op1.getOpcode() == ISD::Constant) { 5868 SDValue AndOp1 = Op0.getOperand(1); 5869 5870 if (AndOp1.getOpcode() == ISD::Constant) { 5871 const APInt &AndConst = cast<ConstantSDNode>(AndOp1)->getAPIntValue(); 5872 5873 if (AndConst.isPowerOf2() && 5874 cast<ConstantSDNode>(Op1)->getAPIntValue()==AndConst.logBase2()) { 5875 SDValue SetCC = 5876 DAG.getSetCC(N->getDebugLoc(), 5877 TLI.getSetCCResultType(Op0.getValueType()), 5878 Op0, DAG.getConstant(0, Op0.getValueType()), 5879 ISD::SETNE); 5880 5881 SDValue NewBRCond = DAG.getNode(ISD::BRCOND, N->getDebugLoc(), 5882 MVT::Other, Chain, SetCC, N2); 5883 // Don't add the new BRCond into the worklist or else SimplifySelectCC 5884 // will convert it back to (X & C1) >> C2. 5885 CombineTo(N, NewBRCond, false); 5886 // Truncate is dead. 5887 if (Trunc) { 5888 removeFromWorkList(Trunc); 5889 DAG.DeleteNode(Trunc); 5890 } 5891 // Replace the uses of SRL with SETCC 5892 WorkListRemover DeadNodes(*this); 5893 DAG.ReplaceAllUsesOfValueWith(N1, SetCC, &DeadNodes); 5894 removeFromWorkList(N1.getNode()); 5895 DAG.DeleteNode(N1.getNode()); 5896 return SDValue(N, 0); // Return N so it doesn't get rechecked! 5897 } 5898 } 5899 } 5900 5901 if (Trunc) 5902 // Restore N1 if the above transformation doesn't match. 5903 N1 = N->getOperand(1); 5904 } 5905 5906 // Transform br(xor(x, y)) -> br(x != y) 5907 // Transform br(xor(xor(x,y), 1)) -> br (x == y) 5908 if (N1.hasOneUse() && N1.getOpcode() == ISD::XOR) { 5909 SDNode *TheXor = N1.getNode(); 5910 SDValue Op0 = TheXor->getOperand(0); 5911 SDValue Op1 = TheXor->getOperand(1); 5912 if (Op0.getOpcode() == Op1.getOpcode()) { 5913 // Avoid missing important xor optimizations. 5914 SDValue Tmp = visitXOR(TheXor); 5915 if (Tmp.getNode() && Tmp.getNode() != TheXor) { 5916 DEBUG(dbgs() << "\nReplacing.8 "; 5917 TheXor->dump(&DAG); 5918 dbgs() << "\nWith: "; 5919 Tmp.getNode()->dump(&DAG); 5920 dbgs() << '\n'); 5921 WorkListRemover DeadNodes(*this); 5922 DAG.ReplaceAllUsesOfValueWith(N1, Tmp, &DeadNodes); 5923 removeFromWorkList(TheXor); 5924 DAG.DeleteNode(TheXor); 5925 return DAG.getNode(ISD::BRCOND, N->getDebugLoc(), 5926 MVT::Other, Chain, Tmp, N2); 5927 } 5928 } 5929 5930 if (Op0.getOpcode() != ISD::SETCC && Op1.getOpcode() != ISD::SETCC) { 5931 bool Equal = false; 5932 if (ConstantSDNode *RHSCI = dyn_cast<ConstantSDNode>(Op0)) 5933 if (RHSCI->getAPIntValue() == 1 && Op0.hasOneUse() && 5934 Op0.getOpcode() == ISD::XOR) { 5935 TheXor = Op0.getNode(); 5936 Equal = true; 5937 } 5938 5939 EVT SetCCVT = N1.getValueType(); 5940 if (LegalTypes) 5941 SetCCVT = TLI.getSetCCResultType(SetCCVT); 5942 SDValue SetCC = DAG.getSetCC(TheXor->getDebugLoc(), 5943 SetCCVT, 5944 Op0, Op1, 5945 Equal ? ISD::SETEQ : ISD::SETNE); 5946 // Replace the uses of XOR with SETCC 5947 WorkListRemover DeadNodes(*this); 5948 DAG.ReplaceAllUsesOfValueWith(N1, SetCC, &DeadNodes); 5949 removeFromWorkList(N1.getNode()); 5950 DAG.DeleteNode(N1.getNode()); 5951 return DAG.getNode(ISD::BRCOND, N->getDebugLoc(), 5952 MVT::Other, Chain, SetCC, N2); 5953 } 5954 } 5955 5956 return SDValue(); 5957} 5958 5959// Operand List for BR_CC: Chain, CondCC, CondLHS, CondRHS, DestBB. 5960// 5961SDValue DAGCombiner::visitBR_CC(SDNode *N) { 5962 CondCodeSDNode *CC = cast<CondCodeSDNode>(N->getOperand(1)); 5963 SDValue CondLHS = N->getOperand(2), CondRHS = N->getOperand(3); 5964 5965 // If N is a constant we could fold this into a fallthrough or unconditional 5966 // branch. However that doesn't happen very often in normal code, because 5967 // Instcombine/SimplifyCFG should have handled the available opportunities. 5968 // If we did this folding here, it would be necessary to update the 5969 // MachineBasicBlock CFG, which is awkward. 5970 5971 // Use SimplifySetCC to simplify SETCC's. 5972 SDValue Simp = SimplifySetCC(TLI.getSetCCResultType(CondLHS.getValueType()), 5973 CondLHS, CondRHS, CC->get(), N->getDebugLoc(), 5974 false); 5975 if (Simp.getNode()) AddToWorkList(Simp.getNode()); 5976 5977 // fold to a simpler setcc 5978 if (Simp.getNode() && Simp.getOpcode() == ISD::SETCC) 5979 return DAG.getNode(ISD::BR_CC, N->getDebugLoc(), MVT::Other, 5980 N->getOperand(0), Simp.getOperand(2), 5981 Simp.getOperand(0), Simp.getOperand(1), 5982 N->getOperand(4)); 5983 5984 return SDValue(); 5985} 5986 5987/// canFoldInAddressingMode - Return true if 'Use' is a load or a store that 5988/// uses N as its base pointer and that N may be folded in the load / store 5989/// addressing mode. FIXME: This currently only looks for folding of 5990/// [reg +/- imm] addressing modes. 5991static bool canFoldInAddressingMode(SDNode *N, SDNode *Use, 5992 SelectionDAG &DAG, 5993 const TargetLowering &TLI) { 5994 EVT VT; 5995 if (LoadSDNode *LD = dyn_cast<LoadSDNode>(Use)) { 5996 if (LD->isIndexed() || LD->getBasePtr().getNode() != N) 5997 return false; 5998 VT = Use->getValueType(0); 5999 } else if (StoreSDNode *ST = dyn_cast<StoreSDNode>(Use)) { 6000 if (ST->isIndexed() || ST->getBasePtr().getNode() != N) 6001 return false; 6002 VT = ST->getValue().getValueType(); 6003 } else 6004 return false; 6005 6006 TargetLowering::AddrMode AM; 6007 if (N->getOpcode() == ISD::ADD) { 6008 ConstantSDNode *Offset = dyn_cast<ConstantSDNode>(N->getOperand(1)); 6009 if (Offset) 6010 AM.BaseOffs = Offset->getSExtValue(); 6011 else 6012 return false; 6013 } else if (N->getOpcode() == ISD::SUB) { 6014 ConstantSDNode *Offset = dyn_cast<ConstantSDNode>(N->getOperand(1)); 6015 if (Offset) 6016 AM.BaseOffs = -Offset->getSExtValue(); 6017 else 6018 return false; 6019 } else 6020 return false; 6021 6022 return TLI.isLegalAddressingMode(AM, VT.getTypeForEVT(*DAG.getContext())); 6023} 6024 6025/// CombineToPreIndexedLoadStore - Try turning a load / store into a 6026/// pre-indexed load / store when the base pointer is an add or subtract 6027/// and it has other uses besides the load / store. After the 6028/// transformation, the new indexed load / store has effectively folded 6029/// the add / subtract in and all of its other uses are redirected to the 6030/// new load / store. 6031bool DAGCombiner::CombineToPreIndexedLoadStore(SDNode *N) { 6032 if (Level < AfterLegalizeDAG) 6033 return false; 6034 6035 bool isLoad = true; 6036 SDValue Ptr; 6037 EVT VT; 6038 if (LoadSDNode *LD = dyn_cast<LoadSDNode>(N)) { 6039 if (LD->isIndexed()) 6040 return false; 6041 VT = LD->getMemoryVT(); 6042 if (!TLI.isIndexedLoadLegal(ISD::PRE_INC, VT) && 6043 !TLI.isIndexedLoadLegal(ISD::PRE_DEC, VT)) 6044 return false; 6045 Ptr = LD->getBasePtr(); 6046 } else if (StoreSDNode *ST = dyn_cast<StoreSDNode>(N)) { 6047 if (ST->isIndexed()) 6048 return false; 6049 VT = ST->getMemoryVT(); 6050 if (!TLI.isIndexedStoreLegal(ISD::PRE_INC, VT) && 6051 !TLI.isIndexedStoreLegal(ISD::PRE_DEC, VT)) 6052 return false; 6053 Ptr = ST->getBasePtr(); 6054 isLoad = false; 6055 } else { 6056 return false; 6057 } 6058 6059 // If the pointer is not an add/sub, or if it doesn't have multiple uses, bail 6060 // out. There is no reason to make this a preinc/predec. 6061 if ((Ptr.getOpcode() != ISD::ADD && Ptr.getOpcode() != ISD::SUB) || 6062 Ptr.getNode()->hasOneUse()) 6063 return false; 6064 6065 // Ask the target to do addressing mode selection. 6066 SDValue BasePtr; 6067 SDValue Offset; 6068 ISD::MemIndexedMode AM = ISD::UNINDEXED; 6069 if (!TLI.getPreIndexedAddressParts(N, BasePtr, Offset, AM, DAG)) 6070 return false; 6071 // Don't create a indexed load / store with zero offset. 6072 if (isa<ConstantSDNode>(Offset) && 6073 cast<ConstantSDNode>(Offset)->isNullValue()) 6074 return false; 6075 6076 // Try turning it into a pre-indexed load / store except when: 6077 // 1) The new base ptr is a frame index. 6078 // 2) If N is a store and the new base ptr is either the same as or is a 6079 // predecessor of the value being stored. 6080 // 3) Another use of old base ptr is a predecessor of N. If ptr is folded 6081 // that would create a cycle. 6082 // 4) All uses are load / store ops that use it as old base ptr. 6083 6084 // Check #1. Preinc'ing a frame index would require copying the stack pointer 6085 // (plus the implicit offset) to a register to preinc anyway. 6086 if (isa<FrameIndexSDNode>(BasePtr) || isa<RegisterSDNode>(BasePtr)) 6087 return false; 6088 6089 // Check #2. 6090 if (!isLoad) { 6091 SDValue Val = cast<StoreSDNode>(N)->getValue(); 6092 if (Val == BasePtr || BasePtr.getNode()->isPredecessorOf(Val.getNode())) 6093 return false; 6094 } 6095 6096 // Now check for #3 and #4. 6097 bool RealUse = false; 6098 6099 // Caches for hasPredecessorHelper 6100 SmallPtrSet<const SDNode *, 32> Visited; 6101 SmallVector<const SDNode *, 16> Worklist; 6102 6103 for (SDNode::use_iterator I = Ptr.getNode()->use_begin(), 6104 E = Ptr.getNode()->use_end(); I != E; ++I) { 6105 SDNode *Use = *I; 6106 if (Use == N) 6107 continue; 6108 if (N->hasPredecessorHelper(Use, Visited, Worklist)) 6109 return false; 6110 6111 // If Ptr may be folded in addressing mode of other use, then it's 6112 // not profitable to do this transformation. 6113 if (!canFoldInAddressingMode(Ptr.getNode(), Use, DAG, TLI)) 6114 RealUse = true; 6115 } 6116 6117 if (!RealUse) 6118 return false; 6119 6120 SDValue Result; 6121 if (isLoad) 6122 Result = DAG.getIndexedLoad(SDValue(N,0), N->getDebugLoc(), 6123 BasePtr, Offset, AM); 6124 else 6125 Result = DAG.getIndexedStore(SDValue(N,0), N->getDebugLoc(), 6126 BasePtr, Offset, AM); 6127 ++PreIndexedNodes; 6128 ++NodesCombined; 6129 DEBUG(dbgs() << "\nReplacing.4 "; 6130 N->dump(&DAG); 6131 dbgs() << "\nWith: "; 6132 Result.getNode()->dump(&DAG); 6133 dbgs() << '\n'); 6134 WorkListRemover DeadNodes(*this); 6135 if (isLoad) { 6136 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Result.getValue(0), 6137 &DeadNodes); 6138 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), Result.getValue(2), 6139 &DeadNodes); 6140 } else { 6141 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Result.getValue(1), 6142 &DeadNodes); 6143 } 6144 6145 // Finally, since the node is now dead, remove it from the graph. 6146 DAG.DeleteNode(N); 6147 6148 // Replace the uses of Ptr with uses of the updated base value. 6149 DAG.ReplaceAllUsesOfValueWith(Ptr, Result.getValue(isLoad ? 1 : 0), 6150 &DeadNodes); 6151 removeFromWorkList(Ptr.getNode()); 6152 DAG.DeleteNode(Ptr.getNode()); 6153 6154 return true; 6155} 6156 6157/// CombineToPostIndexedLoadStore - Try to combine a load / store with a 6158/// add / sub of the base pointer node into a post-indexed load / store. 6159/// The transformation folded the add / subtract into the new indexed 6160/// load / store effectively and all of its uses are redirected to the 6161/// new load / store. 6162bool DAGCombiner::CombineToPostIndexedLoadStore(SDNode *N) { 6163 if (Level < AfterLegalizeDAG) 6164 return false; 6165 6166 bool isLoad = true; 6167 SDValue Ptr; 6168 EVT VT; 6169 if (LoadSDNode *LD = dyn_cast<LoadSDNode>(N)) { 6170 if (LD->isIndexed()) 6171 return false; 6172 VT = LD->getMemoryVT(); 6173 if (!TLI.isIndexedLoadLegal(ISD::POST_INC, VT) && 6174 !TLI.isIndexedLoadLegal(ISD::POST_DEC, VT)) 6175 return false; 6176 Ptr = LD->getBasePtr(); 6177 } else if (StoreSDNode *ST = dyn_cast<StoreSDNode>(N)) { 6178 if (ST->isIndexed()) 6179 return false; 6180 VT = ST->getMemoryVT(); 6181 if (!TLI.isIndexedStoreLegal(ISD::POST_INC, VT) && 6182 !TLI.isIndexedStoreLegal(ISD::POST_DEC, VT)) 6183 return false; 6184 Ptr = ST->getBasePtr(); 6185 isLoad = false; 6186 } else { 6187 return false; 6188 } 6189 6190 if (Ptr.getNode()->hasOneUse()) 6191 return false; 6192 6193 for (SDNode::use_iterator I = Ptr.getNode()->use_begin(), 6194 E = Ptr.getNode()->use_end(); I != E; ++I) { 6195 SDNode *Op = *I; 6196 if (Op == N || 6197 (Op->getOpcode() != ISD::ADD && Op->getOpcode() != ISD::SUB)) 6198 continue; 6199 6200 SDValue BasePtr; 6201 SDValue Offset; 6202 ISD::MemIndexedMode AM = ISD::UNINDEXED; 6203 if (TLI.getPostIndexedAddressParts(N, Op, BasePtr, Offset, AM, DAG)) { 6204 // Don't create a indexed load / store with zero offset. 6205 if (isa<ConstantSDNode>(Offset) && 6206 cast<ConstantSDNode>(Offset)->isNullValue()) 6207 continue; 6208 6209 // Try turning it into a post-indexed load / store except when 6210 // 1) All uses are load / store ops that use it as base ptr (and 6211 // it may be folded as addressing mmode). 6212 // 2) Op must be independent of N, i.e. Op is neither a predecessor 6213 // nor a successor of N. Otherwise, if Op is folded that would 6214 // create a cycle. 6215 6216 if (isa<FrameIndexSDNode>(BasePtr) || isa<RegisterSDNode>(BasePtr)) 6217 continue; 6218 6219 // Check for #1. 6220 bool TryNext = false; 6221 for (SDNode::use_iterator II = BasePtr.getNode()->use_begin(), 6222 EE = BasePtr.getNode()->use_end(); II != EE; ++II) { 6223 SDNode *Use = *II; 6224 if (Use == Ptr.getNode()) 6225 continue; 6226 6227 // If all the uses are load / store addresses, then don't do the 6228 // transformation. 6229 if (Use->getOpcode() == ISD::ADD || Use->getOpcode() == ISD::SUB){ 6230 bool RealUse = false; 6231 for (SDNode::use_iterator III = Use->use_begin(), 6232 EEE = Use->use_end(); III != EEE; ++III) { 6233 SDNode *UseUse = *III; 6234 if (!canFoldInAddressingMode(Use, UseUse, DAG, TLI)) 6235 RealUse = true; 6236 } 6237 6238 if (!RealUse) { 6239 TryNext = true; 6240 break; 6241 } 6242 } 6243 } 6244 6245 if (TryNext) 6246 continue; 6247 6248 // Check for #2 6249 if (!Op->isPredecessorOf(N) && !N->isPredecessorOf(Op)) { 6250 SDValue Result = isLoad 6251 ? DAG.getIndexedLoad(SDValue(N,0), N->getDebugLoc(), 6252 BasePtr, Offset, AM) 6253 : DAG.getIndexedStore(SDValue(N,0), N->getDebugLoc(), 6254 BasePtr, Offset, AM); 6255 ++PostIndexedNodes; 6256 ++NodesCombined; 6257 DEBUG(dbgs() << "\nReplacing.5 "; 6258 N->dump(&DAG); 6259 dbgs() << "\nWith: "; 6260 Result.getNode()->dump(&DAG); 6261 dbgs() << '\n'); 6262 WorkListRemover DeadNodes(*this); 6263 if (isLoad) { 6264 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Result.getValue(0), 6265 &DeadNodes); 6266 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), Result.getValue(2), 6267 &DeadNodes); 6268 } else { 6269 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Result.getValue(1), 6270 &DeadNodes); 6271 } 6272 6273 // Finally, since the node is now dead, remove it from the graph. 6274 DAG.DeleteNode(N); 6275 6276 // Replace the uses of Use with uses of the updated base value. 6277 DAG.ReplaceAllUsesOfValueWith(SDValue(Op, 0), 6278 Result.getValue(isLoad ? 1 : 0), 6279 &DeadNodes); 6280 removeFromWorkList(Op); 6281 DAG.DeleteNode(Op); 6282 return true; 6283 } 6284 } 6285 } 6286 6287 return false; 6288} 6289 6290SDValue DAGCombiner::visitLOAD(SDNode *N) { 6291 LoadSDNode *LD = cast<LoadSDNode>(N); 6292 SDValue Chain = LD->getChain(); 6293 SDValue Ptr = LD->getBasePtr(); 6294 6295 // If load is not volatile and there are no uses of the loaded value (and 6296 // the updated indexed value in case of indexed loads), change uses of the 6297 // chain value into uses of the chain input (i.e. delete the dead load). 6298 if (!LD->isVolatile()) { 6299 if (N->getValueType(1) == MVT::Other) { 6300 // Unindexed loads. 6301 if (!N->hasAnyUseOfValue(0)) { 6302 // It's not safe to use the two value CombineTo variant here. e.g. 6303 // v1, chain2 = load chain1, loc 6304 // v2, chain3 = load chain2, loc 6305 // v3 = add v2, c 6306 // Now we replace use of chain2 with chain1. This makes the second load 6307 // isomorphic to the one we are deleting, and thus makes this load live. 6308 DEBUG(dbgs() << "\nReplacing.6 "; 6309 N->dump(&DAG); 6310 dbgs() << "\nWith chain: "; 6311 Chain.getNode()->dump(&DAG); 6312 dbgs() << "\n"); 6313 WorkListRemover DeadNodes(*this); 6314 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), Chain, &DeadNodes); 6315 6316 if (N->use_empty()) { 6317 removeFromWorkList(N); 6318 DAG.DeleteNode(N); 6319 } 6320 6321 return SDValue(N, 0); // Return N so it doesn't get rechecked! 6322 } 6323 } else { 6324 // Indexed loads. 6325 assert(N->getValueType(2) == MVT::Other && "Malformed indexed loads?"); 6326 if (!N->hasAnyUseOfValue(0) && !N->hasAnyUseOfValue(1)) { 6327 SDValue Undef = DAG.getUNDEF(N->getValueType(0)); 6328 DEBUG(dbgs() << "\nReplacing.7 "; 6329 N->dump(&DAG); 6330 dbgs() << "\nWith: "; 6331 Undef.getNode()->dump(&DAG); 6332 dbgs() << " and 2 other values\n"); 6333 WorkListRemover DeadNodes(*this); 6334 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Undef, &DeadNodes); 6335 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), 6336 DAG.getUNDEF(N->getValueType(1)), 6337 &DeadNodes); 6338 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 2), Chain, &DeadNodes); 6339 removeFromWorkList(N); 6340 DAG.DeleteNode(N); 6341 return SDValue(N, 0); // Return N so it doesn't get rechecked! 6342 } 6343 } 6344 } 6345 6346 // If this load is directly stored, replace the load value with the stored 6347 // value. 6348 // TODO: Handle store large -> read small portion. 6349 // TODO: Handle TRUNCSTORE/LOADEXT 6350 if (ISD::isNormalLoad(N) && !LD->isVolatile()) { 6351 if (ISD::isNON_TRUNCStore(Chain.getNode())) { 6352 StoreSDNode *PrevST = cast<StoreSDNode>(Chain); 6353 if (PrevST->getBasePtr() == Ptr && 6354 PrevST->getValue().getValueType() == N->getValueType(0)) 6355 return CombineTo(N, Chain.getOperand(1), Chain); 6356 } 6357 } 6358 6359 // Try to infer better alignment information than the load already has. 6360 if (OptLevel != CodeGenOpt::None && LD->isUnindexed()) { 6361 if (unsigned Align = DAG.InferPtrAlignment(Ptr)) { 6362 if (Align > LD->getAlignment()) 6363 return DAG.getExtLoad(LD->getExtensionType(), N->getDebugLoc(), 6364 LD->getValueType(0), 6365 Chain, Ptr, LD->getPointerInfo(), 6366 LD->getMemoryVT(), 6367 LD->isVolatile(), LD->isNonTemporal(), Align); 6368 } 6369 } 6370 6371 if (CombinerAA) { 6372 // Walk up chain skipping non-aliasing memory nodes. 6373 SDValue BetterChain = FindBetterChain(N, Chain); 6374 6375 // If there is a better chain. 6376 if (Chain != BetterChain) { 6377 SDValue ReplLoad; 6378 6379 // Replace the chain to void dependency. 6380 if (LD->getExtensionType() == ISD::NON_EXTLOAD) { 6381 ReplLoad = DAG.getLoad(N->getValueType(0), LD->getDebugLoc(), 6382 BetterChain, Ptr, LD->getPointerInfo(), 6383 LD->isVolatile(), LD->isNonTemporal(), 6384 LD->isInvariant(), LD->getAlignment()); 6385 } else { 6386 ReplLoad = DAG.getExtLoad(LD->getExtensionType(), LD->getDebugLoc(), 6387 LD->getValueType(0), 6388 BetterChain, Ptr, LD->getPointerInfo(), 6389 LD->getMemoryVT(), 6390 LD->isVolatile(), 6391 LD->isNonTemporal(), 6392 LD->getAlignment()); 6393 } 6394 6395 // Create token factor to keep old chain connected. 6396 SDValue Token = DAG.getNode(ISD::TokenFactor, N->getDebugLoc(), 6397 MVT::Other, Chain, ReplLoad.getValue(1)); 6398 6399 // Make sure the new and old chains are cleaned up. 6400 AddToWorkList(Token.getNode()); 6401 6402 // Replace uses with load result and token factor. Don't add users 6403 // to work list. 6404 return CombineTo(N, ReplLoad.getValue(0), Token, false); 6405 } 6406 } 6407 6408 // Try transforming N to an indexed load. 6409 if (CombineToPreIndexedLoadStore(N) || CombineToPostIndexedLoadStore(N)) 6410 return SDValue(N, 0); 6411 6412 return SDValue(); 6413} 6414 6415/// CheckForMaskedLoad - Check to see if V is (and load (ptr), imm), where the 6416/// load is having specific bytes cleared out. If so, return the byte size 6417/// being masked out and the shift amount. 6418static std::pair<unsigned, unsigned> 6419CheckForMaskedLoad(SDValue V, SDValue Ptr, SDValue Chain) { 6420 std::pair<unsigned, unsigned> Result(0, 0); 6421 6422 // Check for the structure we're looking for. 6423 if (V->getOpcode() != ISD::AND || 6424 !isa<ConstantSDNode>(V->getOperand(1)) || 6425 !ISD::isNormalLoad(V->getOperand(0).getNode())) 6426 return Result; 6427 6428 // Check the chain and pointer. 6429 LoadSDNode *LD = cast<LoadSDNode>(V->getOperand(0)); 6430 if (LD->getBasePtr() != Ptr) return Result; // Not from same pointer. 6431 6432 // The store should be chained directly to the load or be an operand of a 6433 // tokenfactor. 6434 if (LD == Chain.getNode()) 6435 ; // ok. 6436 else if (Chain->getOpcode() != ISD::TokenFactor) 6437 return Result; // Fail. 6438 else { 6439 bool isOk = false; 6440 for (unsigned i = 0, e = Chain->getNumOperands(); i != e; ++i) 6441 if (Chain->getOperand(i).getNode() == LD) { 6442 isOk = true; 6443 break; 6444 } 6445 if (!isOk) return Result; 6446 } 6447 6448 // This only handles simple types. 6449 if (V.getValueType() != MVT::i16 && 6450 V.getValueType() != MVT::i32 && 6451 V.getValueType() != MVT::i64) 6452 return Result; 6453 6454 // Check the constant mask. Invert it so that the bits being masked out are 6455 // 0 and the bits being kept are 1. Use getSExtValue so that leading bits 6456 // follow the sign bit for uniformity. 6457 uint64_t NotMask = ~cast<ConstantSDNode>(V->getOperand(1))->getSExtValue(); 6458 unsigned NotMaskLZ = CountLeadingZeros_64(NotMask); 6459 if (NotMaskLZ & 7) return Result; // Must be multiple of a byte. 6460 unsigned NotMaskTZ = CountTrailingZeros_64(NotMask); 6461 if (NotMaskTZ & 7) return Result; // Must be multiple of a byte. 6462 if (NotMaskLZ == 64) return Result; // All zero mask. 6463 6464 // See if we have a continuous run of bits. If so, we have 0*1+0* 6465 if (CountTrailingOnes_64(NotMask >> NotMaskTZ)+NotMaskTZ+NotMaskLZ != 64) 6466 return Result; 6467 6468 // Adjust NotMaskLZ down to be from the actual size of the int instead of i64. 6469 if (V.getValueType() != MVT::i64 && NotMaskLZ) 6470 NotMaskLZ -= 64-V.getValueSizeInBits(); 6471 6472 unsigned MaskedBytes = (V.getValueSizeInBits()-NotMaskLZ-NotMaskTZ)/8; 6473 switch (MaskedBytes) { 6474 case 1: 6475 case 2: 6476 case 4: break; 6477 default: return Result; // All one mask, or 5-byte mask. 6478 } 6479 6480 // Verify that the first bit starts at a multiple of mask so that the access 6481 // is aligned the same as the access width. 6482 if (NotMaskTZ && NotMaskTZ/8 % MaskedBytes) return Result; 6483 6484 Result.first = MaskedBytes; 6485 Result.second = NotMaskTZ/8; 6486 return Result; 6487} 6488 6489 6490/// ShrinkLoadReplaceStoreWithStore - Check to see if IVal is something that 6491/// provides a value as specified by MaskInfo. If so, replace the specified 6492/// store with a narrower store of truncated IVal. 6493static SDNode * 6494ShrinkLoadReplaceStoreWithStore(const std::pair<unsigned, unsigned> &MaskInfo, 6495 SDValue IVal, StoreSDNode *St, 6496 DAGCombiner *DC) { 6497 unsigned NumBytes = MaskInfo.first; 6498 unsigned ByteShift = MaskInfo.second; 6499 SelectionDAG &DAG = DC->getDAG(); 6500 6501 // Check to see if IVal is all zeros in the part being masked in by the 'or' 6502 // that uses this. If not, this is not a replacement. 6503 APInt Mask = ~APInt::getBitsSet(IVal.getValueSizeInBits(), 6504 ByteShift*8, (ByteShift+NumBytes)*8); 6505 if (!DAG.MaskedValueIsZero(IVal, Mask)) return 0; 6506 6507 // Check that it is legal on the target to do this. It is legal if the new 6508 // VT we're shrinking to (i8/i16/i32) is legal or we're still before type 6509 // legalization. 6510 MVT VT = MVT::getIntegerVT(NumBytes*8); 6511 if (!DC->isTypeLegal(VT)) 6512 return 0; 6513 6514 // Okay, we can do this! Replace the 'St' store with a store of IVal that is 6515 // shifted by ByteShift and truncated down to NumBytes. 6516 if (ByteShift) 6517 IVal = DAG.getNode(ISD::SRL, IVal->getDebugLoc(), IVal.getValueType(), IVal, 6518 DAG.getConstant(ByteShift*8, 6519 DC->getShiftAmountTy(IVal.getValueType()))); 6520 6521 // Figure out the offset for the store and the alignment of the access. 6522 unsigned StOffset; 6523 unsigned NewAlign = St->getAlignment(); 6524 6525 if (DAG.getTargetLoweringInfo().isLittleEndian()) 6526 StOffset = ByteShift; 6527 else 6528 StOffset = IVal.getValueType().getStoreSize() - ByteShift - NumBytes; 6529 6530 SDValue Ptr = St->getBasePtr(); 6531 if (StOffset) { 6532 Ptr = DAG.getNode(ISD::ADD, IVal->getDebugLoc(), Ptr.getValueType(), 6533 Ptr, DAG.getConstant(StOffset, Ptr.getValueType())); 6534 NewAlign = MinAlign(NewAlign, StOffset); 6535 } 6536 6537 // Truncate down to the new size. 6538 IVal = DAG.getNode(ISD::TRUNCATE, IVal->getDebugLoc(), VT, IVal); 6539 6540 ++OpsNarrowed; 6541 return DAG.getStore(St->getChain(), St->getDebugLoc(), IVal, Ptr, 6542 St->getPointerInfo().getWithOffset(StOffset), 6543 false, false, NewAlign).getNode(); 6544} 6545 6546 6547/// ReduceLoadOpStoreWidth - Look for sequence of load / op / store where op is 6548/// one of 'or', 'xor', and 'and' of immediates. If 'op' is only touching some 6549/// of the loaded bits, try narrowing the load and store if it would end up 6550/// being a win for performance or code size. 6551SDValue DAGCombiner::ReduceLoadOpStoreWidth(SDNode *N) { 6552 StoreSDNode *ST = cast<StoreSDNode>(N); 6553 if (ST->isVolatile()) 6554 return SDValue(); 6555 6556 SDValue Chain = ST->getChain(); 6557 SDValue Value = ST->getValue(); 6558 SDValue Ptr = ST->getBasePtr(); 6559 EVT VT = Value.getValueType(); 6560 6561 if (ST->isTruncatingStore() || VT.isVector() || !Value.hasOneUse()) 6562 return SDValue(); 6563 6564 unsigned Opc = Value.getOpcode(); 6565 6566 // If this is "store (or X, Y), P" and X is "(and (load P), cst)", where cst 6567 // is a byte mask indicating a consecutive number of bytes, check to see if 6568 // Y is known to provide just those bytes. If so, we try to replace the 6569 // load + replace + store sequence with a single (narrower) store, which makes 6570 // the load dead. 6571 if (Opc == ISD::OR) { 6572 std::pair<unsigned, unsigned> MaskedLoad; 6573 MaskedLoad = CheckForMaskedLoad(Value.getOperand(0), Ptr, Chain); 6574 if (MaskedLoad.first) 6575 if (SDNode *NewST = ShrinkLoadReplaceStoreWithStore(MaskedLoad, 6576 Value.getOperand(1), ST,this)) 6577 return SDValue(NewST, 0); 6578 6579 // Or is commutative, so try swapping X and Y. 6580 MaskedLoad = CheckForMaskedLoad(Value.getOperand(1), Ptr, Chain); 6581 if (MaskedLoad.first) 6582 if (SDNode *NewST = ShrinkLoadReplaceStoreWithStore(MaskedLoad, 6583 Value.getOperand(0), ST,this)) 6584 return SDValue(NewST, 0); 6585 } 6586 6587 if ((Opc != ISD::OR && Opc != ISD::XOR && Opc != ISD::AND) || 6588 Value.getOperand(1).getOpcode() != ISD::Constant) 6589 return SDValue(); 6590 6591 SDValue N0 = Value.getOperand(0); 6592 if (ISD::isNormalLoad(N0.getNode()) && N0.hasOneUse() && 6593 Chain == SDValue(N0.getNode(), 1)) { 6594 LoadSDNode *LD = cast<LoadSDNode>(N0); 6595 if (LD->getBasePtr() != Ptr || 6596 LD->getPointerInfo().getAddrSpace() != 6597 ST->getPointerInfo().getAddrSpace()) 6598 return SDValue(); 6599 6600 // Find the type to narrow it the load / op / store to. 6601 SDValue N1 = Value.getOperand(1); 6602 unsigned BitWidth = N1.getValueSizeInBits(); 6603 APInt Imm = cast<ConstantSDNode>(N1)->getAPIntValue(); 6604 if (Opc == ISD::AND) 6605 Imm ^= APInt::getAllOnesValue(BitWidth); 6606 if (Imm == 0 || Imm.isAllOnesValue()) 6607 return SDValue(); 6608 unsigned ShAmt = Imm.countTrailingZeros(); 6609 unsigned MSB = BitWidth - Imm.countLeadingZeros() - 1; 6610 unsigned NewBW = NextPowerOf2(MSB - ShAmt); 6611 EVT NewVT = EVT::getIntegerVT(*DAG.getContext(), NewBW); 6612 while (NewBW < BitWidth && 6613 !(TLI.isOperationLegalOrCustom(Opc, NewVT) && 6614 TLI.isNarrowingProfitable(VT, NewVT))) { 6615 NewBW = NextPowerOf2(NewBW); 6616 NewVT = EVT::getIntegerVT(*DAG.getContext(), NewBW); 6617 } 6618 if (NewBW >= BitWidth) 6619 return SDValue(); 6620 6621 // If the lsb changed does not start at the type bitwidth boundary, 6622 // start at the previous one. 6623 if (ShAmt % NewBW) 6624 ShAmt = (((ShAmt + NewBW - 1) / NewBW) * NewBW) - NewBW; 6625 APInt Mask = APInt::getBitsSet(BitWidth, ShAmt, ShAmt + NewBW); 6626 if ((Imm & Mask) == Imm) { 6627 APInt NewImm = (Imm & Mask).lshr(ShAmt).trunc(NewBW); 6628 if (Opc == ISD::AND) 6629 NewImm ^= APInt::getAllOnesValue(NewBW); 6630 uint64_t PtrOff = ShAmt / 8; 6631 // For big endian targets, we need to adjust the offset to the pointer to 6632 // load the correct bytes. 6633 if (TLI.isBigEndian()) 6634 PtrOff = (BitWidth + 7 - NewBW) / 8 - PtrOff; 6635 6636 unsigned NewAlign = MinAlign(LD->getAlignment(), PtrOff); 6637 Type *NewVTTy = NewVT.getTypeForEVT(*DAG.getContext()); 6638 if (NewAlign < TLI.getTargetData()->getABITypeAlignment(NewVTTy)) 6639 return SDValue(); 6640 6641 SDValue NewPtr = DAG.getNode(ISD::ADD, LD->getDebugLoc(), 6642 Ptr.getValueType(), Ptr, 6643 DAG.getConstant(PtrOff, Ptr.getValueType())); 6644 SDValue NewLD = DAG.getLoad(NewVT, N0.getDebugLoc(), 6645 LD->getChain(), NewPtr, 6646 LD->getPointerInfo().getWithOffset(PtrOff), 6647 LD->isVolatile(), LD->isNonTemporal(), 6648 LD->isInvariant(), NewAlign); 6649 SDValue NewVal = DAG.getNode(Opc, Value.getDebugLoc(), NewVT, NewLD, 6650 DAG.getConstant(NewImm, NewVT)); 6651 SDValue NewST = DAG.getStore(Chain, N->getDebugLoc(), 6652 NewVal, NewPtr, 6653 ST->getPointerInfo().getWithOffset(PtrOff), 6654 false, false, NewAlign); 6655 6656 AddToWorkList(NewPtr.getNode()); 6657 AddToWorkList(NewLD.getNode()); 6658 AddToWorkList(NewVal.getNode()); 6659 WorkListRemover DeadNodes(*this); 6660 DAG.ReplaceAllUsesOfValueWith(N0.getValue(1), NewLD.getValue(1), 6661 &DeadNodes); 6662 ++OpsNarrowed; 6663 return NewST; 6664 } 6665 } 6666 6667 return SDValue(); 6668} 6669 6670/// TransformFPLoadStorePair - For a given floating point load / store pair, 6671/// if the load value isn't used by any other operations, then consider 6672/// transforming the pair to integer load / store operations if the target 6673/// deems the transformation profitable. 6674SDValue DAGCombiner::TransformFPLoadStorePair(SDNode *N) { 6675 StoreSDNode *ST = cast<StoreSDNode>(N); 6676 SDValue Chain = ST->getChain(); 6677 SDValue Value = ST->getValue(); 6678 if (ISD::isNormalStore(ST) && ISD::isNormalLoad(Value.getNode()) && 6679 Value.hasOneUse() && 6680 Chain == SDValue(Value.getNode(), 1)) { 6681 LoadSDNode *LD = cast<LoadSDNode>(Value); 6682 EVT VT = LD->getMemoryVT(); 6683 if (!VT.isFloatingPoint() || 6684 VT != ST->getMemoryVT() || 6685 LD->isNonTemporal() || 6686 ST->isNonTemporal() || 6687 LD->getPointerInfo().getAddrSpace() != 0 || 6688 ST->getPointerInfo().getAddrSpace() != 0) 6689 return SDValue(); 6690 6691 EVT IntVT = EVT::getIntegerVT(*DAG.getContext(), VT.getSizeInBits()); 6692 if (!TLI.isOperationLegal(ISD::LOAD, IntVT) || 6693 !TLI.isOperationLegal(ISD::STORE, IntVT) || 6694 !TLI.isDesirableToTransformToIntegerOp(ISD::LOAD, VT) || 6695 !TLI.isDesirableToTransformToIntegerOp(ISD::STORE, VT)) 6696 return SDValue(); 6697 6698 unsigned LDAlign = LD->getAlignment(); 6699 unsigned STAlign = ST->getAlignment(); 6700 Type *IntVTTy = IntVT.getTypeForEVT(*DAG.getContext()); 6701 unsigned ABIAlign = TLI.getTargetData()->getABITypeAlignment(IntVTTy); 6702 if (LDAlign < ABIAlign || STAlign < ABIAlign) 6703 return SDValue(); 6704 6705 SDValue NewLD = DAG.getLoad(IntVT, Value.getDebugLoc(), 6706 LD->getChain(), LD->getBasePtr(), 6707 LD->getPointerInfo(), 6708 false, false, false, LDAlign); 6709 6710 SDValue NewST = DAG.getStore(NewLD.getValue(1), N->getDebugLoc(), 6711 NewLD, ST->getBasePtr(), 6712 ST->getPointerInfo(), 6713 false, false, STAlign); 6714 6715 AddToWorkList(NewLD.getNode()); 6716 AddToWorkList(NewST.getNode()); 6717 WorkListRemover DeadNodes(*this); 6718 DAG.ReplaceAllUsesOfValueWith(Value.getValue(1), NewLD.getValue(1), 6719 &DeadNodes); 6720 ++LdStFP2Int; 6721 return NewST; 6722 } 6723 6724 return SDValue(); 6725} 6726 6727SDValue DAGCombiner::visitSTORE(SDNode *N) { 6728 StoreSDNode *ST = cast<StoreSDNode>(N); 6729 SDValue Chain = ST->getChain(); 6730 SDValue Value = ST->getValue(); 6731 SDValue Ptr = ST->getBasePtr(); 6732 6733 // If this is a store of a bit convert, store the input value if the 6734 // resultant store does not need a higher alignment than the original. 6735 if (Value.getOpcode() == ISD::BITCAST && !ST->isTruncatingStore() && 6736 ST->isUnindexed()) { 6737 unsigned OrigAlign = ST->getAlignment(); 6738 EVT SVT = Value.getOperand(0).getValueType(); 6739 unsigned Align = TLI.getTargetData()-> 6740 getABITypeAlignment(SVT.getTypeForEVT(*DAG.getContext())); 6741 if (Align <= OrigAlign && 6742 ((!LegalOperations && !ST->isVolatile()) || 6743 TLI.isOperationLegalOrCustom(ISD::STORE, SVT))) 6744 return DAG.getStore(Chain, N->getDebugLoc(), Value.getOperand(0), 6745 Ptr, ST->getPointerInfo(), ST->isVolatile(), 6746 ST->isNonTemporal(), OrigAlign); 6747 } 6748 6749 // Turn 'store undef, Ptr' -> nothing. 6750 if (Value.getOpcode() == ISD::UNDEF && ST->isUnindexed()) 6751 return Chain; 6752 6753 // Turn 'store float 1.0, Ptr' -> 'store int 0x12345678, Ptr' 6754 if (ConstantFPSDNode *CFP = dyn_cast<ConstantFPSDNode>(Value)) { 6755 // NOTE: If the original store is volatile, this transform must not increase 6756 // the number of stores. For example, on x86-32 an f64 can be stored in one 6757 // processor operation but an i64 (which is not legal) requires two. So the 6758 // transform should not be done in this case. 6759 if (Value.getOpcode() != ISD::TargetConstantFP) { 6760 SDValue Tmp; 6761 switch (CFP->getValueType(0).getSimpleVT().SimpleTy) { 6762 default: llvm_unreachable("Unknown FP type"); 6763 case MVT::f80: // We don't do this for these yet. 6764 case MVT::f128: 6765 case MVT::ppcf128: 6766 break; 6767 case MVT::f32: 6768 if ((isTypeLegal(MVT::i32) && !LegalOperations && !ST->isVolatile()) || 6769 TLI.isOperationLegalOrCustom(ISD::STORE, MVT::i32)) { 6770 Tmp = DAG.getConstant((uint32_t)CFP->getValueAPF(). 6771 bitcastToAPInt().getZExtValue(), MVT::i32); 6772 return DAG.getStore(Chain, N->getDebugLoc(), Tmp, 6773 Ptr, ST->getPointerInfo(), ST->isVolatile(), 6774 ST->isNonTemporal(), ST->getAlignment()); 6775 } 6776 break; 6777 case MVT::f64: 6778 if ((TLI.isTypeLegal(MVT::i64) && !LegalOperations && 6779 !ST->isVolatile()) || 6780 TLI.isOperationLegalOrCustom(ISD::STORE, MVT::i64)) { 6781 Tmp = DAG.getConstant(CFP->getValueAPF().bitcastToAPInt(). 6782 getZExtValue(), MVT::i64); 6783 return DAG.getStore(Chain, N->getDebugLoc(), Tmp, 6784 Ptr, ST->getPointerInfo(), ST->isVolatile(), 6785 ST->isNonTemporal(), ST->getAlignment()); 6786 } 6787 6788 if (!ST->isVolatile() && 6789 TLI.isOperationLegalOrCustom(ISD::STORE, MVT::i32)) { 6790 // Many FP stores are not made apparent until after legalize, e.g. for 6791 // argument passing. Since this is so common, custom legalize the 6792 // 64-bit integer store into two 32-bit stores. 6793 uint64_t Val = CFP->getValueAPF().bitcastToAPInt().getZExtValue(); 6794 SDValue Lo = DAG.getConstant(Val & 0xFFFFFFFF, MVT::i32); 6795 SDValue Hi = DAG.getConstant(Val >> 32, MVT::i32); 6796 if (TLI.isBigEndian()) std::swap(Lo, Hi); 6797 6798 unsigned Alignment = ST->getAlignment(); 6799 bool isVolatile = ST->isVolatile(); 6800 bool isNonTemporal = ST->isNonTemporal(); 6801 6802 SDValue St0 = DAG.getStore(Chain, ST->getDebugLoc(), Lo, 6803 Ptr, ST->getPointerInfo(), 6804 isVolatile, isNonTemporal, 6805 ST->getAlignment()); 6806 Ptr = DAG.getNode(ISD::ADD, N->getDebugLoc(), Ptr.getValueType(), Ptr, 6807 DAG.getConstant(4, Ptr.getValueType())); 6808 Alignment = MinAlign(Alignment, 4U); 6809 SDValue St1 = DAG.getStore(Chain, ST->getDebugLoc(), Hi, 6810 Ptr, ST->getPointerInfo().getWithOffset(4), 6811 isVolatile, isNonTemporal, 6812 Alignment); 6813 return DAG.getNode(ISD::TokenFactor, N->getDebugLoc(), MVT::Other, 6814 St0, St1); 6815 } 6816 6817 break; 6818 } 6819 } 6820 } 6821 6822 // Try to infer better alignment information than the store already has. 6823 if (OptLevel != CodeGenOpt::None && ST->isUnindexed()) { 6824 if (unsigned Align = DAG.InferPtrAlignment(Ptr)) { 6825 if (Align > ST->getAlignment()) 6826 return DAG.getTruncStore(Chain, N->getDebugLoc(), Value, 6827 Ptr, ST->getPointerInfo(), ST->getMemoryVT(), 6828 ST->isVolatile(), ST->isNonTemporal(), Align); 6829 } 6830 } 6831 6832 // Try transforming a pair floating point load / store ops to integer 6833 // load / store ops. 6834 SDValue NewST = TransformFPLoadStorePair(N); 6835 if (NewST.getNode()) 6836 return NewST; 6837 6838 if (CombinerAA) { 6839 // Walk up chain skipping non-aliasing memory nodes. 6840 SDValue BetterChain = FindBetterChain(N, Chain); 6841 6842 // If there is a better chain. 6843 if (Chain != BetterChain) { 6844 SDValue ReplStore; 6845 6846 // Replace the chain to avoid dependency. 6847 if (ST->isTruncatingStore()) { 6848 ReplStore = DAG.getTruncStore(BetterChain, N->getDebugLoc(), Value, Ptr, 6849 ST->getPointerInfo(), 6850 ST->getMemoryVT(), ST->isVolatile(), 6851 ST->isNonTemporal(), ST->getAlignment()); 6852 } else { 6853 ReplStore = DAG.getStore(BetterChain, N->getDebugLoc(), Value, Ptr, 6854 ST->getPointerInfo(), 6855 ST->isVolatile(), ST->isNonTemporal(), 6856 ST->getAlignment()); 6857 } 6858 6859 // Create token to keep both nodes around. 6860 SDValue Token = DAG.getNode(ISD::TokenFactor, N->getDebugLoc(), 6861 MVT::Other, Chain, ReplStore); 6862 6863 // Make sure the new and old chains are cleaned up. 6864 AddToWorkList(Token.getNode()); 6865 6866 // Don't add users to work list. 6867 return CombineTo(N, Token, false); 6868 } 6869 } 6870 6871 // Try transforming N to an indexed store. 6872 if (CombineToPreIndexedLoadStore(N) || CombineToPostIndexedLoadStore(N)) 6873 return SDValue(N, 0); 6874 6875 // FIXME: is there such a thing as a truncating indexed store? 6876 if (ST->isTruncatingStore() && ST->isUnindexed() && 6877 Value.getValueType().isInteger()) { 6878 // See if we can simplify the input to this truncstore with knowledge that 6879 // only the low bits are being used. For example: 6880 // "truncstore (or (shl x, 8), y), i8" -> "truncstore y, i8" 6881 SDValue Shorter = 6882 GetDemandedBits(Value, 6883 APInt::getLowBitsSet( 6884 Value.getValueType().getScalarType().getSizeInBits(), 6885 ST->getMemoryVT().getScalarType().getSizeInBits())); 6886 AddToWorkList(Value.getNode()); 6887 if (Shorter.getNode()) 6888 return DAG.getTruncStore(Chain, N->getDebugLoc(), Shorter, 6889 Ptr, ST->getPointerInfo(), ST->getMemoryVT(), 6890 ST->isVolatile(), ST->isNonTemporal(), 6891 ST->getAlignment()); 6892 6893 // Otherwise, see if we can simplify the operation with 6894 // SimplifyDemandedBits, which only works if the value has a single use. 6895 if (SimplifyDemandedBits(Value, 6896 APInt::getLowBitsSet( 6897 Value.getValueType().getScalarType().getSizeInBits(), 6898 ST->getMemoryVT().getScalarType().getSizeInBits()))) 6899 return SDValue(N, 0); 6900 } 6901 6902 // If this is a load followed by a store to the same location, then the store 6903 // is dead/noop. 6904 if (LoadSDNode *Ld = dyn_cast<LoadSDNode>(Value)) { 6905 if (Ld->getBasePtr() == Ptr && ST->getMemoryVT() == Ld->getMemoryVT() && 6906 ST->isUnindexed() && !ST->isVolatile() && 6907 // There can't be any side effects between the load and store, such as 6908 // a call or store. 6909 Chain.reachesChainWithoutSideEffects(SDValue(Ld, 1))) { 6910 // The store is dead, remove it. 6911 return Chain; 6912 } 6913 } 6914 6915 // If this is an FP_ROUND or TRUNC followed by a store, fold this into a 6916 // truncating store. We can do this even if this is already a truncstore. 6917 if ((Value.getOpcode() == ISD::FP_ROUND || Value.getOpcode() == ISD::TRUNCATE) 6918 && Value.getNode()->hasOneUse() && ST->isUnindexed() && 6919 TLI.isTruncStoreLegal(Value.getOperand(0).getValueType(), 6920 ST->getMemoryVT())) { 6921 return DAG.getTruncStore(Chain, N->getDebugLoc(), Value.getOperand(0), 6922 Ptr, ST->getPointerInfo(), ST->getMemoryVT(), 6923 ST->isVolatile(), ST->isNonTemporal(), 6924 ST->getAlignment()); 6925 } 6926 6927 return ReduceLoadOpStoreWidth(N); 6928} 6929 6930SDValue DAGCombiner::visitINSERT_VECTOR_ELT(SDNode *N) { 6931 SDValue InVec = N->getOperand(0); 6932 SDValue InVal = N->getOperand(1); 6933 SDValue EltNo = N->getOperand(2); 6934 DebugLoc dl = N->getDebugLoc(); 6935 6936 // If the inserted element is an UNDEF, just use the input vector. 6937 if (InVal.getOpcode() == ISD::UNDEF) 6938 return InVec; 6939 6940 EVT VT = InVec.getValueType(); 6941 6942 // If we can't generate a legal BUILD_VECTOR, exit 6943 if (LegalOperations && !TLI.isOperationLegal(ISD::BUILD_VECTOR, VT)) 6944 return SDValue(); 6945 6946 // Check that we know which element is being inserted 6947 if (!isa<ConstantSDNode>(EltNo)) 6948 return SDValue(); 6949 unsigned Elt = cast<ConstantSDNode>(EltNo)->getZExtValue(); 6950 6951 // Check that the operand is a BUILD_VECTOR (or UNDEF, which can essentially 6952 // be converted to a BUILD_VECTOR). Fill in the Ops vector with the 6953 // vector elements. 6954 SmallVector<SDValue, 8> Ops; 6955 if (InVec.getOpcode() == ISD::BUILD_VECTOR) { 6956 Ops.append(InVec.getNode()->op_begin(), 6957 InVec.getNode()->op_end()); 6958 } else if (InVec.getOpcode() == ISD::UNDEF) { 6959 unsigned NElts = VT.getVectorNumElements(); 6960 Ops.append(NElts, DAG.getUNDEF(InVal.getValueType())); 6961 } else { 6962 return SDValue(); 6963 } 6964 6965 // Insert the element 6966 if (Elt < Ops.size()) { 6967 // All the operands of BUILD_VECTOR must have the same type; 6968 // we enforce that here. 6969 EVT OpVT = Ops[0].getValueType(); 6970 if (InVal.getValueType() != OpVT) 6971 InVal = OpVT.bitsGT(InVal.getValueType()) ? 6972 DAG.getNode(ISD::ANY_EXTEND, dl, OpVT, InVal) : 6973 DAG.getNode(ISD::TRUNCATE, dl, OpVT, InVal); 6974 Ops[Elt] = InVal; 6975 } 6976 6977 // Return the new vector 6978 return DAG.getNode(ISD::BUILD_VECTOR, dl, 6979 VT, &Ops[0], Ops.size()); 6980} 6981 6982SDValue DAGCombiner::visitEXTRACT_VECTOR_ELT(SDNode *N) { 6983 // (vextract (scalar_to_vector val, 0) -> val 6984 SDValue InVec = N->getOperand(0); 6985 6986 if (InVec.getOpcode() == ISD::SCALAR_TO_VECTOR) { 6987 // Check if the result type doesn't match the inserted element type. A 6988 // SCALAR_TO_VECTOR may truncate the inserted element and the 6989 // EXTRACT_VECTOR_ELT may widen the extracted vector. 6990 SDValue InOp = InVec.getOperand(0); 6991 EVT NVT = N->getValueType(0); 6992 if (InOp.getValueType() != NVT) { 6993 assert(InOp.getValueType().isInteger() && NVT.isInteger()); 6994 return DAG.getSExtOrTrunc(InOp, InVec.getDebugLoc(), NVT); 6995 } 6996 return InOp; 6997 } 6998 6999 // Perform only after legalization to ensure build_vector / vector_shuffle 7000 // optimizations have already been done. 7001 if (!LegalOperations) return SDValue(); 7002 7003 // (vextract (v4f32 load $addr), c) -> (f32 load $addr+c*size) 7004 // (vextract (v4f32 s2v (f32 load $addr)), c) -> (f32 load $addr+c*size) 7005 // (vextract (v4f32 shuffle (load $addr), <1,u,u,u>), 0) -> (f32 load $addr) 7006 SDValue EltNo = N->getOperand(1); 7007 7008 if (isa<ConstantSDNode>(EltNo)) { 7009 int Elt = cast<ConstantSDNode>(EltNo)->getZExtValue(); 7010 bool NewLoad = false; 7011 bool BCNumEltsChanged = false; 7012 EVT VT = InVec.getValueType(); 7013 EVT ExtVT = VT.getVectorElementType(); 7014 EVT LVT = ExtVT; 7015 7016 if (InVec.getOpcode() == ISD::BITCAST) { 7017 // Don't duplicate a load with other uses. 7018 if (!InVec.hasOneUse()) 7019 return SDValue(); 7020 7021 EVT BCVT = InVec.getOperand(0).getValueType(); 7022 if (!BCVT.isVector() || ExtVT.bitsGT(BCVT.getVectorElementType())) 7023 return SDValue(); 7024 if (VT.getVectorNumElements() != BCVT.getVectorNumElements()) 7025 BCNumEltsChanged = true; 7026 InVec = InVec.getOperand(0); 7027 ExtVT = BCVT.getVectorElementType(); 7028 NewLoad = true; 7029 } 7030 7031 LoadSDNode *LN0 = NULL; 7032 const ShuffleVectorSDNode *SVN = NULL; 7033 if (ISD::isNormalLoad(InVec.getNode())) { 7034 LN0 = cast<LoadSDNode>(InVec); 7035 } else if (InVec.getOpcode() == ISD::SCALAR_TO_VECTOR && 7036 InVec.getOperand(0).getValueType() == ExtVT && 7037 ISD::isNormalLoad(InVec.getOperand(0).getNode())) { 7038 // Don't duplicate a load with other uses. 7039 if (!InVec.hasOneUse()) 7040 return SDValue(); 7041 7042 LN0 = cast<LoadSDNode>(InVec.getOperand(0)); 7043 } else if ((SVN = dyn_cast<ShuffleVectorSDNode>(InVec))) { 7044 // (vextract (vector_shuffle (load $addr), v2, <1, u, u, u>), 1) 7045 // => 7046 // (load $addr+1*size) 7047 7048 // Don't duplicate a load with other uses. 7049 if (!InVec.hasOneUse()) 7050 return SDValue(); 7051 7052 // If the bit convert changed the number of elements, it is unsafe 7053 // to examine the mask. 7054 if (BCNumEltsChanged) 7055 return SDValue(); 7056 7057 // Select the input vector, guarding against out of range extract vector. 7058 unsigned NumElems = VT.getVectorNumElements(); 7059 int Idx = (Elt > (int)NumElems) ? -1 : SVN->getMaskElt(Elt); 7060 InVec = (Idx < (int)NumElems) ? InVec.getOperand(0) : InVec.getOperand(1); 7061 7062 if (InVec.getOpcode() == ISD::BITCAST) { 7063 // Don't duplicate a load with other uses. 7064 if (!InVec.hasOneUse()) 7065 return SDValue(); 7066 7067 InVec = InVec.getOperand(0); 7068 } 7069 if (ISD::isNormalLoad(InVec.getNode())) { 7070 LN0 = cast<LoadSDNode>(InVec); 7071 Elt = (Idx < (int)NumElems) ? Idx : Idx - (int)NumElems; 7072 } 7073 } 7074 7075 // Make sure we found a non-volatile load and the extractelement is 7076 // the only use. 7077 if (!LN0 || !LN0->hasNUsesOfValue(1,0) || LN0->isVolatile()) 7078 return SDValue(); 7079 7080 // If Idx was -1 above, Elt is going to be -1, so just return undef. 7081 if (Elt == -1) 7082 return DAG.getUNDEF(LVT); 7083 7084 unsigned Align = LN0->getAlignment(); 7085 if (NewLoad) { 7086 // Check the resultant load doesn't need a higher alignment than the 7087 // original load. 7088 unsigned NewAlign = 7089 TLI.getTargetData() 7090 ->getABITypeAlignment(LVT.getTypeForEVT(*DAG.getContext())); 7091 7092 if (NewAlign > Align || !TLI.isOperationLegalOrCustom(ISD::LOAD, LVT)) 7093 return SDValue(); 7094 7095 Align = NewAlign; 7096 } 7097 7098 SDValue NewPtr = LN0->getBasePtr(); 7099 unsigned PtrOff = 0; 7100 7101 if (Elt) { 7102 PtrOff = LVT.getSizeInBits() * Elt / 8; 7103 EVT PtrType = NewPtr.getValueType(); 7104 if (TLI.isBigEndian()) 7105 PtrOff = VT.getSizeInBits() / 8 - PtrOff; 7106 NewPtr = DAG.getNode(ISD::ADD, N->getDebugLoc(), PtrType, NewPtr, 7107 DAG.getConstant(PtrOff, PtrType)); 7108 } 7109 7110 // The replacement we need to do here is a little tricky: we need to 7111 // replace an extractelement of a load with a load. 7112 // Use ReplaceAllUsesOfValuesWith to do the replacement. 7113 // Note that this replacement assumes that the extractvalue is the only 7114 // use of the load; that's okay because we don't want to perform this 7115 // transformation in other cases anyway. 7116 SDValue Load = DAG.getLoad(LVT, N->getDebugLoc(), LN0->getChain(), NewPtr, 7117 LN0->getPointerInfo().getWithOffset(PtrOff), 7118 LN0->isVolatile(), LN0->isNonTemporal(), 7119 LN0->isInvariant(), Align); 7120 WorkListRemover DeadNodes(*this); 7121 SDValue From[] = { SDValue(N, 0), SDValue(LN0,1) }; 7122 SDValue To[] = { Load.getValue(0), Load.getValue(1) }; 7123 DAG.ReplaceAllUsesOfValuesWith(From, To, 2, &DeadNodes); 7124 // Since we're explcitly calling ReplaceAllUses, add the new node to the 7125 // worklist explicitly as well. 7126 AddToWorkList(Load.getNode()); 7127 // Make sure to revisit this node to clean it up; it will usually be dead. 7128 AddToWorkList(N); 7129 return SDValue(N, 0); 7130 } 7131 7132 return SDValue(); 7133} 7134 7135SDValue DAGCombiner::visitBUILD_VECTOR(SDNode *N) { 7136 unsigned NumInScalars = N->getNumOperands(); 7137 DebugLoc dl = N->getDebugLoc(); 7138 EVT VT = N->getValueType(0); 7139 // Check to see if this is a BUILD_VECTOR of a bunch of values 7140 // which come from any_extend or zero_extend nodes. If so, we can create 7141 // a new BUILD_VECTOR using bit-casts which may enable other BUILD_VECTOR 7142 // optimizations. We do not handle sign-extend because we can't fill the sign 7143 // using shuffles. 7144 EVT SourceType = MVT::Other; 7145 bool allAnyExt = true; 7146 for (unsigned i = 0; i < NumInScalars; ++i) { 7147 SDValue In = N->getOperand(i); 7148 // Ignore undef inputs. 7149 if (In.getOpcode() == ISD::UNDEF) continue; 7150 7151 bool AnyExt = In.getOpcode() == ISD::ANY_EXTEND; 7152 bool ZeroExt = In.getOpcode() == ISD::ZERO_EXTEND; 7153 7154 // Abort if the element is not an extension. 7155 if (!ZeroExt && !AnyExt) { 7156 SourceType = MVT::Other; 7157 break; 7158 } 7159 7160 // The input is a ZeroExt or AnyExt. Check the original type. 7161 EVT InTy = In.getOperand(0).getValueType(); 7162 7163 // Check that all of the widened source types are the same. 7164 if (SourceType == MVT::Other) 7165 // First time. 7166 SourceType = InTy; 7167 else if (InTy != SourceType) { 7168 // Multiple income types. Abort. 7169 SourceType = MVT::Other; 7170 break; 7171 } 7172 7173 // Check if all of the extends are ANY_EXTENDs. 7174 allAnyExt &= AnyExt; 7175 } 7176 7177 7178 // In order to have valid types, all of the inputs must be extended from the 7179 // same source type and all of the inputs must be any or zero extend. 7180 // Scalar sizes must be a power of two. 7181 EVT OutScalarTy = N->getValueType(0).getScalarType(); 7182 bool validTypes = SourceType != MVT::Other && 7183 isPowerOf2_32(OutScalarTy.getSizeInBits()) && 7184 isPowerOf2_32(SourceType.getSizeInBits()); 7185 7186 // We perform this optimization post type-legalization because 7187 // the type-legalizer often scalarizes integer-promoted vectors. 7188 // Performing this optimization before may create bit-casts which 7189 // will be type-legalized to complex code sequences. 7190 // We perform this optimization only before the operation legalizer because we 7191 // may introduce illegal operations. 7192 if (LegalTypes && !LegalOperations && validTypes) { 7193 bool isLE = TLI.isLittleEndian(); 7194 unsigned ElemRatio = OutScalarTy.getSizeInBits()/SourceType.getSizeInBits(); 7195 assert(ElemRatio > 1 && "Invalid element size ratio"); 7196 SDValue Filler = allAnyExt ? DAG.getUNDEF(SourceType): 7197 DAG.getConstant(0, SourceType); 7198 7199 unsigned NewBVElems = ElemRatio * N->getValueType(0).getVectorNumElements(); 7200 SmallVector<SDValue, 8> Ops(NewBVElems, Filler); 7201 7202 // Populate the new build_vector 7203 for (unsigned i=0; i < N->getNumOperands(); ++i) { 7204 SDValue Cast = N->getOperand(i); 7205 assert((Cast.getOpcode() == ISD::ANY_EXTEND || 7206 Cast.getOpcode() == ISD::ZERO_EXTEND || 7207 Cast.getOpcode() == ISD::UNDEF) && "Invalid cast opcode"); 7208 SDValue In; 7209 if (Cast.getOpcode() == ISD::UNDEF) 7210 In = DAG.getUNDEF(SourceType); 7211 else 7212 In = Cast->getOperand(0); 7213 unsigned Index = isLE ? (i * ElemRatio) : 7214 (i * ElemRatio + (ElemRatio - 1)); 7215 7216 assert(Index < Ops.size() && "Invalid index"); 7217 Ops[Index] = In; 7218 } 7219 7220 // The type of the new BUILD_VECTOR node. 7221 EVT VecVT = EVT::getVectorVT(*DAG.getContext(), SourceType, NewBVElems); 7222 assert(VecVT.getSizeInBits() == N->getValueType(0).getSizeInBits() && 7223 "Invalid vector size"); 7224 // Check if the new vector type is legal. 7225 if (!isTypeLegal(VecVT)) return SDValue(); 7226 7227 // Make the new BUILD_VECTOR. 7228 SDValue BV = DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(), 7229 VecVT, &Ops[0], Ops.size()); 7230 7231 // Bitcast to the desired type. 7232 return DAG.getNode(ISD::BITCAST, dl, N->getValueType(0), BV); 7233 } 7234 7235 // Check to see if this is a BUILD_VECTOR of a bunch of EXTRACT_VECTOR_ELT 7236 // operations. If so, and if the EXTRACT_VECTOR_ELT vector inputs come from 7237 // at most two distinct vectors, turn this into a shuffle node. 7238 SDValue VecIn1, VecIn2; 7239 for (unsigned i = 0; i != NumInScalars; ++i) { 7240 // Ignore undef inputs. 7241 if (N->getOperand(i).getOpcode() == ISD::UNDEF) continue; 7242 7243 // If this input is something other than a EXTRACT_VECTOR_ELT with a 7244 // constant index, bail out. 7245 if (N->getOperand(i).getOpcode() != ISD::EXTRACT_VECTOR_ELT || 7246 !isa<ConstantSDNode>(N->getOperand(i).getOperand(1))) { 7247 VecIn1 = VecIn2 = SDValue(0, 0); 7248 break; 7249 } 7250 7251 // If the input vector type disagrees with the result of the build_vector, 7252 // we can't make a shuffle. 7253 SDValue ExtractedFromVec = N->getOperand(i).getOperand(0); 7254 if (ExtractedFromVec.getValueType() != VT) { 7255 VecIn1 = VecIn2 = SDValue(0, 0); 7256 break; 7257 } 7258 7259 // Otherwise, remember this. We allow up to two distinct input vectors. 7260 if (ExtractedFromVec == VecIn1 || ExtractedFromVec == VecIn2) 7261 continue; 7262 7263 if (VecIn1.getNode() == 0) { 7264 VecIn1 = ExtractedFromVec; 7265 } else if (VecIn2.getNode() == 0) { 7266 VecIn2 = ExtractedFromVec; 7267 } else { 7268 // Too many inputs. 7269 VecIn1 = VecIn2 = SDValue(0, 0); 7270 break; 7271 } 7272 } 7273 7274 // If everything is good, we can make a shuffle operation. 7275 if (VecIn1.getNode()) { 7276 SmallVector<int, 8> Mask; 7277 for (unsigned i = 0; i != NumInScalars; ++i) { 7278 if (N->getOperand(i).getOpcode() == ISD::UNDEF) { 7279 Mask.push_back(-1); 7280 continue; 7281 } 7282 7283 // If extracting from the first vector, just use the index directly. 7284 SDValue Extract = N->getOperand(i); 7285 SDValue ExtVal = Extract.getOperand(1); 7286 if (Extract.getOperand(0) == VecIn1) { 7287 unsigned ExtIndex = cast<ConstantSDNode>(ExtVal)->getZExtValue(); 7288 if (ExtIndex > VT.getVectorNumElements()) 7289 return SDValue(); 7290 7291 Mask.push_back(ExtIndex); 7292 continue; 7293 } 7294 7295 // Otherwise, use InIdx + VecSize 7296 unsigned Idx = cast<ConstantSDNode>(ExtVal)->getZExtValue(); 7297 Mask.push_back(Idx+NumInScalars); 7298 } 7299 7300 // Add count and size info. 7301 if (!isTypeLegal(VT)) 7302 return SDValue(); 7303 7304 // Return the new VECTOR_SHUFFLE node. 7305 SDValue Ops[2]; 7306 Ops[0] = VecIn1; 7307 Ops[1] = VecIn2.getNode() ? VecIn2 : DAG.getUNDEF(VT); 7308 return DAG.getVectorShuffle(VT, N->getDebugLoc(), Ops[0], Ops[1], &Mask[0]); 7309 } 7310 7311 return SDValue(); 7312} 7313 7314SDValue DAGCombiner::visitCONCAT_VECTORS(SDNode *N) { 7315 // TODO: Check to see if this is a CONCAT_VECTORS of a bunch of 7316 // EXTRACT_SUBVECTOR operations. If so, and if the EXTRACT_SUBVECTOR vector 7317 // inputs come from at most two distinct vectors, turn this into a shuffle 7318 // node. 7319 7320 // If we only have one input vector, we don't need to do any concatenation. 7321 if (N->getNumOperands() == 1) 7322 return N->getOperand(0); 7323 7324 return SDValue(); 7325} 7326 7327SDValue DAGCombiner::visitEXTRACT_SUBVECTOR(SDNode* N) { 7328 EVT NVT = N->getValueType(0); 7329 SDValue V = N->getOperand(0); 7330 7331 if (V->getOpcode() == ISD::INSERT_SUBVECTOR) { 7332 // Handle only simple case where vector being inserted and vector 7333 // being extracted are of same type, and are half size of larger vectors. 7334 EVT BigVT = V->getOperand(0).getValueType(); 7335 EVT SmallVT = V->getOperand(1).getValueType(); 7336 if (NVT != SmallVT || NVT.getSizeInBits()*2 != BigVT.getSizeInBits()) 7337 return SDValue(); 7338 7339 // Only handle cases where both indexes are constants with the same type. 7340 ConstantSDNode *InsIdx = dyn_cast<ConstantSDNode>(N->getOperand(1)); 7341 ConstantSDNode *ExtIdx = dyn_cast<ConstantSDNode>(V->getOperand(2)); 7342 7343 if (InsIdx && ExtIdx && 7344 InsIdx->getValueType(0).getSizeInBits() <= 64 && 7345 ExtIdx->getValueType(0).getSizeInBits() <= 64) { 7346 // Combine: 7347 // (extract_subvec (insert_subvec V1, V2, InsIdx), ExtIdx) 7348 // Into: 7349 // indices are equal => V1 7350 // otherwise => (extract_subvec V1, ExtIdx) 7351 if (InsIdx->getZExtValue() == ExtIdx->getZExtValue()) 7352 return V->getOperand(1); 7353 return DAG.getNode(ISD::EXTRACT_SUBVECTOR, N->getDebugLoc(), NVT, 7354 V->getOperand(0), N->getOperand(1)); 7355 } 7356 } 7357 7358 return SDValue(); 7359} 7360 7361SDValue DAGCombiner::visitVECTOR_SHUFFLE(SDNode *N) { 7362 EVT VT = N->getValueType(0); 7363 unsigned NumElts = VT.getVectorNumElements(); 7364 7365 SDValue N0 = N->getOperand(0); 7366 SDValue N1 = N->getOperand(1); 7367 7368 assert(N0.getValueType().getVectorNumElements() == NumElts && 7369 "Vector shuffle must be normalized in DAG"); 7370 7371 // Canonicalize shuffle undef, undef -> undef 7372 if (N0.getOpcode() == ISD::UNDEF && N1.getOpcode() == ISD::UNDEF) 7373 return DAG.getUNDEF(VT); 7374 7375 ShuffleVectorSDNode *SVN = cast<ShuffleVectorSDNode>(N); 7376 7377 // Canonicalize shuffle v, v -> v, undef 7378 if (N0 == N1) { 7379 SmallVector<int, 8> NewMask; 7380 for (unsigned i = 0; i != NumElts; ++i) { 7381 int Idx = SVN->getMaskElt(i); 7382 if (Idx >= (int)NumElts) Idx -= NumElts; 7383 NewMask.push_back(Idx); 7384 } 7385 return DAG.getVectorShuffle(VT, N->getDebugLoc(), N0, DAG.getUNDEF(VT), 7386 &NewMask[0]); 7387 } 7388 7389 // Canonicalize shuffle undef, v -> v, undef. Commute the shuffle mask. 7390 if (N0.getOpcode() == ISD::UNDEF) { 7391 SmallVector<int, 8> NewMask; 7392 for (unsigned i = 0; i != NumElts; ++i) { 7393 int Idx = SVN->getMaskElt(i); 7394 if (Idx < 0) 7395 NewMask.push_back(Idx); 7396 else if (Idx < (int)NumElts) 7397 NewMask.push_back(Idx + NumElts); 7398 else 7399 NewMask.push_back(Idx - NumElts); 7400 } 7401 return DAG.getVectorShuffle(VT, N->getDebugLoc(), N1, DAG.getUNDEF(VT), 7402 &NewMask[0]); 7403 } 7404 7405 // Remove references to rhs if it is undef 7406 if (N1.getOpcode() == ISD::UNDEF) { 7407 bool Changed = false; 7408 SmallVector<int, 8> NewMask; 7409 for (unsigned i = 0; i != NumElts; ++i) { 7410 int Idx = SVN->getMaskElt(i); 7411 if (Idx >= (int)NumElts) { 7412 Idx = -1; 7413 Changed = true; 7414 } 7415 NewMask.push_back(Idx); 7416 } 7417 if (Changed) 7418 return DAG.getVectorShuffle(VT, N->getDebugLoc(), N0, N1, &NewMask[0]); 7419 } 7420 7421 // If it is a splat, check if the argument vector is another splat or a 7422 // build_vector with all scalar elements the same. 7423 if (SVN->isSplat() && SVN->getSplatIndex() < (int)NumElts) { 7424 SDNode *V = N0.getNode(); 7425 7426 // If this is a bit convert that changes the element type of the vector but 7427 // not the number of vector elements, look through it. Be careful not to 7428 // look though conversions that change things like v4f32 to v2f64. 7429 if (V->getOpcode() == ISD::BITCAST) { 7430 SDValue ConvInput = V->getOperand(0); 7431 if (ConvInput.getValueType().isVector() && 7432 ConvInput.getValueType().getVectorNumElements() == NumElts) 7433 V = ConvInput.getNode(); 7434 } 7435 7436 if (V->getOpcode() == ISD::BUILD_VECTOR) { 7437 assert(V->getNumOperands() == NumElts && 7438 "BUILD_VECTOR has wrong number of operands"); 7439 SDValue Base; 7440 bool AllSame = true; 7441 for (unsigned i = 0; i != NumElts; ++i) { 7442 if (V->getOperand(i).getOpcode() != ISD::UNDEF) { 7443 Base = V->getOperand(i); 7444 break; 7445 } 7446 } 7447 // Splat of <u, u, u, u>, return <u, u, u, u> 7448 if (!Base.getNode()) 7449 return N0; 7450 for (unsigned i = 0; i != NumElts; ++i) { 7451 if (V->getOperand(i) != Base) { 7452 AllSame = false; 7453 break; 7454 } 7455 } 7456 // Splat of <x, x, x, x>, return <x, x, x, x> 7457 if (AllSame) 7458 return N0; 7459 } 7460 } 7461 return SDValue(); 7462} 7463 7464SDValue DAGCombiner::visitMEMBARRIER(SDNode* N) { 7465 if (!TLI.getShouldFoldAtomicFences()) 7466 return SDValue(); 7467 7468 SDValue atomic = N->getOperand(0); 7469 switch (atomic.getOpcode()) { 7470 case ISD::ATOMIC_CMP_SWAP: 7471 case ISD::ATOMIC_SWAP: 7472 case ISD::ATOMIC_LOAD_ADD: 7473 case ISD::ATOMIC_LOAD_SUB: 7474 case ISD::ATOMIC_LOAD_AND: 7475 case ISD::ATOMIC_LOAD_OR: 7476 case ISD::ATOMIC_LOAD_XOR: 7477 case ISD::ATOMIC_LOAD_NAND: 7478 case ISD::ATOMIC_LOAD_MIN: 7479 case ISD::ATOMIC_LOAD_MAX: 7480 case ISD::ATOMIC_LOAD_UMIN: 7481 case ISD::ATOMIC_LOAD_UMAX: 7482 break; 7483 default: 7484 return SDValue(); 7485 } 7486 7487 SDValue fence = atomic.getOperand(0); 7488 if (fence.getOpcode() != ISD::MEMBARRIER) 7489 return SDValue(); 7490 7491 switch (atomic.getOpcode()) { 7492 case ISD::ATOMIC_CMP_SWAP: 7493 return SDValue(DAG.UpdateNodeOperands(atomic.getNode(), 7494 fence.getOperand(0), 7495 atomic.getOperand(1), atomic.getOperand(2), 7496 atomic.getOperand(3)), atomic.getResNo()); 7497 case ISD::ATOMIC_SWAP: 7498 case ISD::ATOMIC_LOAD_ADD: 7499 case ISD::ATOMIC_LOAD_SUB: 7500 case ISD::ATOMIC_LOAD_AND: 7501 case ISD::ATOMIC_LOAD_OR: 7502 case ISD::ATOMIC_LOAD_XOR: 7503 case ISD::ATOMIC_LOAD_NAND: 7504 case ISD::ATOMIC_LOAD_MIN: 7505 case ISD::ATOMIC_LOAD_MAX: 7506 case ISD::ATOMIC_LOAD_UMIN: 7507 case ISD::ATOMIC_LOAD_UMAX: 7508 return SDValue(DAG.UpdateNodeOperands(atomic.getNode(), 7509 fence.getOperand(0), 7510 atomic.getOperand(1), atomic.getOperand(2)), 7511 atomic.getResNo()); 7512 default: 7513 return SDValue(); 7514 } 7515} 7516 7517/// XformToShuffleWithZero - Returns a vector_shuffle if it able to transform 7518/// an AND to a vector_shuffle with the destination vector and a zero vector. 7519/// e.g. AND V, <0xffffffff, 0, 0xffffffff, 0>. ==> 7520/// vector_shuffle V, Zero, <0, 4, 2, 4> 7521SDValue DAGCombiner::XformToShuffleWithZero(SDNode *N) { 7522 EVT VT = N->getValueType(0); 7523 DebugLoc dl = N->getDebugLoc(); 7524 SDValue LHS = N->getOperand(0); 7525 SDValue RHS = N->getOperand(1); 7526 if (N->getOpcode() == ISD::AND) { 7527 if (RHS.getOpcode() == ISD::BITCAST) 7528 RHS = RHS.getOperand(0); 7529 if (RHS.getOpcode() == ISD::BUILD_VECTOR) { 7530 SmallVector<int, 8> Indices; 7531 unsigned NumElts = RHS.getNumOperands(); 7532 for (unsigned i = 0; i != NumElts; ++i) { 7533 SDValue Elt = RHS.getOperand(i); 7534 if (!isa<ConstantSDNode>(Elt)) 7535 return SDValue(); 7536 else if (cast<ConstantSDNode>(Elt)->isAllOnesValue()) 7537 Indices.push_back(i); 7538 else if (cast<ConstantSDNode>(Elt)->isNullValue()) 7539 Indices.push_back(NumElts); 7540 else 7541 return SDValue(); 7542 } 7543 7544 // Let's see if the target supports this vector_shuffle. 7545 EVT RVT = RHS.getValueType(); 7546 if (!TLI.isVectorClearMaskLegal(Indices, RVT)) 7547 return SDValue(); 7548 7549 // Return the new VECTOR_SHUFFLE node. 7550 EVT EltVT = RVT.getVectorElementType(); 7551 SmallVector<SDValue,8> ZeroOps(RVT.getVectorNumElements(), 7552 DAG.getConstant(0, EltVT)); 7553 SDValue Zero = DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(), 7554 RVT, &ZeroOps[0], ZeroOps.size()); 7555 LHS = DAG.getNode(ISD::BITCAST, dl, RVT, LHS); 7556 SDValue Shuf = DAG.getVectorShuffle(RVT, dl, LHS, Zero, &Indices[0]); 7557 return DAG.getNode(ISD::BITCAST, dl, VT, Shuf); 7558 } 7559 } 7560 7561 return SDValue(); 7562} 7563 7564/// SimplifyVBinOp - Visit a binary vector operation, like ADD. 7565SDValue DAGCombiner::SimplifyVBinOp(SDNode *N) { 7566 // After legalize, the target may be depending on adds and other 7567 // binary ops to provide legal ways to construct constants or other 7568 // things. Simplifying them may result in a loss of legality. 7569 if (LegalOperations) return SDValue(); 7570 7571 assert(N->getValueType(0).isVector() && 7572 "SimplifyVBinOp only works on vectors!"); 7573 7574 SDValue LHS = N->getOperand(0); 7575 SDValue RHS = N->getOperand(1); 7576 SDValue Shuffle = XformToShuffleWithZero(N); 7577 if (Shuffle.getNode()) return Shuffle; 7578 7579 // If the LHS and RHS are BUILD_VECTOR nodes, see if we can constant fold 7580 // this operation. 7581 if (LHS.getOpcode() == ISD::BUILD_VECTOR && 7582 RHS.getOpcode() == ISD::BUILD_VECTOR) { 7583 SmallVector<SDValue, 8> Ops; 7584 for (unsigned i = 0, e = LHS.getNumOperands(); i != e; ++i) { 7585 SDValue LHSOp = LHS.getOperand(i); 7586 SDValue RHSOp = RHS.getOperand(i); 7587 // If these two elements can't be folded, bail out. 7588 if ((LHSOp.getOpcode() != ISD::UNDEF && 7589 LHSOp.getOpcode() != ISD::Constant && 7590 LHSOp.getOpcode() != ISD::ConstantFP) || 7591 (RHSOp.getOpcode() != ISD::UNDEF && 7592 RHSOp.getOpcode() != ISD::Constant && 7593 RHSOp.getOpcode() != ISD::ConstantFP)) 7594 break; 7595 7596 // Can't fold divide by zero. 7597 if (N->getOpcode() == ISD::SDIV || N->getOpcode() == ISD::UDIV || 7598 N->getOpcode() == ISD::FDIV) { 7599 if ((RHSOp.getOpcode() == ISD::Constant && 7600 cast<ConstantSDNode>(RHSOp.getNode())->isNullValue()) || 7601 (RHSOp.getOpcode() == ISD::ConstantFP && 7602 cast<ConstantFPSDNode>(RHSOp.getNode())->getValueAPF().isZero())) 7603 break; 7604 } 7605 7606 EVT VT = LHSOp.getValueType(); 7607 EVT RVT = RHSOp.getValueType(); 7608 if (RVT != VT) { 7609 // Integer BUILD_VECTOR operands may have types larger than the element 7610 // size (e.g., when the element type is not legal). Prior to type 7611 // legalization, the types may not match between the two BUILD_VECTORS. 7612 // Truncate one of the operands to make them match. 7613 if (RVT.getSizeInBits() > VT.getSizeInBits()) { 7614 RHSOp = DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, RHSOp); 7615 } else { 7616 LHSOp = DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), RVT, LHSOp); 7617 VT = RVT; 7618 } 7619 } 7620 SDValue FoldOp = DAG.getNode(N->getOpcode(), LHS.getDebugLoc(), VT, 7621 LHSOp, RHSOp); 7622 if (FoldOp.getOpcode() != ISD::UNDEF && 7623 FoldOp.getOpcode() != ISD::Constant && 7624 FoldOp.getOpcode() != ISD::ConstantFP) 7625 break; 7626 Ops.push_back(FoldOp); 7627 AddToWorkList(FoldOp.getNode()); 7628 } 7629 7630 if (Ops.size() == LHS.getNumOperands()) 7631 return DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(), 7632 LHS.getValueType(), &Ops[0], Ops.size()); 7633 } 7634 7635 return SDValue(); 7636} 7637 7638SDValue DAGCombiner::SimplifySelect(DebugLoc DL, SDValue N0, 7639 SDValue N1, SDValue N2){ 7640 assert(N0.getOpcode() ==ISD::SETCC && "First argument must be a SetCC node!"); 7641 7642 SDValue SCC = SimplifySelectCC(DL, N0.getOperand(0), N0.getOperand(1), N1, N2, 7643 cast<CondCodeSDNode>(N0.getOperand(2))->get()); 7644 7645 // If we got a simplified select_cc node back from SimplifySelectCC, then 7646 // break it down into a new SETCC node, and a new SELECT node, and then return 7647 // the SELECT node, since we were called with a SELECT node. 7648 if (SCC.getNode()) { 7649 // Check to see if we got a select_cc back (to turn into setcc/select). 7650 // Otherwise, just return whatever node we got back, like fabs. 7651 if (SCC.getOpcode() == ISD::SELECT_CC) { 7652 SDValue SETCC = DAG.getNode(ISD::SETCC, N0.getDebugLoc(), 7653 N0.getValueType(), 7654 SCC.getOperand(0), SCC.getOperand(1), 7655 SCC.getOperand(4)); 7656 AddToWorkList(SETCC.getNode()); 7657 return DAG.getNode(ISD::SELECT, SCC.getDebugLoc(), SCC.getValueType(), 7658 SCC.getOperand(2), SCC.getOperand(3), SETCC); 7659 } 7660 7661 return SCC; 7662 } 7663 return SDValue(); 7664} 7665 7666/// SimplifySelectOps - Given a SELECT or a SELECT_CC node, where LHS and RHS 7667/// are the two values being selected between, see if we can simplify the 7668/// select. Callers of this should assume that TheSelect is deleted if this 7669/// returns true. As such, they should return the appropriate thing (e.g. the 7670/// node) back to the top-level of the DAG combiner loop to avoid it being 7671/// looked at. 7672bool DAGCombiner::SimplifySelectOps(SDNode *TheSelect, SDValue LHS, 7673 SDValue RHS) { 7674 7675 // Cannot simplify select with vector condition 7676 if (TheSelect->getOperand(0).getValueType().isVector()) return false; 7677 7678 // If this is a select from two identical things, try to pull the operation 7679 // through the select. 7680 if (LHS.getOpcode() != RHS.getOpcode() || 7681 !LHS.hasOneUse() || !RHS.hasOneUse()) 7682 return false; 7683 7684 // If this is a load and the token chain is identical, replace the select 7685 // of two loads with a load through a select of the address to load from. 7686 // This triggers in things like "select bool X, 10.0, 123.0" after the FP 7687 // constants have been dropped into the constant pool. 7688 if (LHS.getOpcode() == ISD::LOAD) { 7689 LoadSDNode *LLD = cast<LoadSDNode>(LHS); 7690 LoadSDNode *RLD = cast<LoadSDNode>(RHS); 7691 7692 // Token chains must be identical. 7693 if (LHS.getOperand(0) != RHS.getOperand(0) || 7694 // Do not let this transformation reduce the number of volatile loads. 7695 LLD->isVolatile() || RLD->isVolatile() || 7696 // If this is an EXTLOAD, the VT's must match. 7697 LLD->getMemoryVT() != RLD->getMemoryVT() || 7698 // If this is an EXTLOAD, the kind of extension must match. 7699 (LLD->getExtensionType() != RLD->getExtensionType() && 7700 // The only exception is if one of the extensions is anyext. 7701 LLD->getExtensionType() != ISD::EXTLOAD && 7702 RLD->getExtensionType() != ISD::EXTLOAD) || 7703 // FIXME: this discards src value information. This is 7704 // over-conservative. It would be beneficial to be able to remember 7705 // both potential memory locations. Since we are discarding 7706 // src value info, don't do the transformation if the memory 7707 // locations are not in the default address space. 7708 LLD->getPointerInfo().getAddrSpace() != 0 || 7709 RLD->getPointerInfo().getAddrSpace() != 0) 7710 return false; 7711 7712 // Check that the select condition doesn't reach either load. If so, 7713 // folding this will induce a cycle into the DAG. If not, this is safe to 7714 // xform, so create a select of the addresses. 7715 SDValue Addr; 7716 if (TheSelect->getOpcode() == ISD::SELECT) { 7717 SDNode *CondNode = TheSelect->getOperand(0).getNode(); 7718 if ((LLD->hasAnyUseOfValue(1) && LLD->isPredecessorOf(CondNode)) || 7719 (RLD->hasAnyUseOfValue(1) && RLD->isPredecessorOf(CondNode))) 7720 return false; 7721 Addr = DAG.getNode(ISD::SELECT, TheSelect->getDebugLoc(), 7722 LLD->getBasePtr().getValueType(), 7723 TheSelect->getOperand(0), LLD->getBasePtr(), 7724 RLD->getBasePtr()); 7725 } else { // Otherwise SELECT_CC 7726 SDNode *CondLHS = TheSelect->getOperand(0).getNode(); 7727 SDNode *CondRHS = TheSelect->getOperand(1).getNode(); 7728 7729 if ((LLD->hasAnyUseOfValue(1) && 7730 (LLD->isPredecessorOf(CondLHS) || LLD->isPredecessorOf(CondRHS))) || 7731 (LLD->hasAnyUseOfValue(1) && 7732 (LLD->isPredecessorOf(CondLHS) || LLD->isPredecessorOf(CondRHS)))) 7733 return false; 7734 7735 Addr = DAG.getNode(ISD::SELECT_CC, TheSelect->getDebugLoc(), 7736 LLD->getBasePtr().getValueType(), 7737 TheSelect->getOperand(0), 7738 TheSelect->getOperand(1), 7739 LLD->getBasePtr(), RLD->getBasePtr(), 7740 TheSelect->getOperand(4)); 7741 } 7742 7743 SDValue Load; 7744 if (LLD->getExtensionType() == ISD::NON_EXTLOAD) { 7745 Load = DAG.getLoad(TheSelect->getValueType(0), 7746 TheSelect->getDebugLoc(), 7747 // FIXME: Discards pointer info. 7748 LLD->getChain(), Addr, MachinePointerInfo(), 7749 LLD->isVolatile(), LLD->isNonTemporal(), 7750 LLD->isInvariant(), LLD->getAlignment()); 7751 } else { 7752 Load = DAG.getExtLoad(LLD->getExtensionType() == ISD::EXTLOAD ? 7753 RLD->getExtensionType() : LLD->getExtensionType(), 7754 TheSelect->getDebugLoc(), 7755 TheSelect->getValueType(0), 7756 // FIXME: Discards pointer info. 7757 LLD->getChain(), Addr, MachinePointerInfo(), 7758 LLD->getMemoryVT(), LLD->isVolatile(), 7759 LLD->isNonTemporal(), LLD->getAlignment()); 7760 } 7761 7762 // Users of the select now use the result of the load. 7763 CombineTo(TheSelect, Load); 7764 7765 // Users of the old loads now use the new load's chain. We know the 7766 // old-load value is dead now. 7767 CombineTo(LHS.getNode(), Load.getValue(0), Load.getValue(1)); 7768 CombineTo(RHS.getNode(), Load.getValue(0), Load.getValue(1)); 7769 return true; 7770 } 7771 7772 return false; 7773} 7774 7775/// SimplifySelectCC - Simplify an expression of the form (N0 cond N1) ? N2 : N3 7776/// where 'cond' is the comparison specified by CC. 7777SDValue DAGCombiner::SimplifySelectCC(DebugLoc DL, SDValue N0, SDValue N1, 7778 SDValue N2, SDValue N3, 7779 ISD::CondCode CC, bool NotExtCompare) { 7780 // (x ? y : y) -> y. 7781 if (N2 == N3) return N2; 7782 7783 EVT VT = N2.getValueType(); 7784 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.getNode()); 7785 ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(N2.getNode()); 7786 ConstantSDNode *N3C = dyn_cast<ConstantSDNode>(N3.getNode()); 7787 7788 // Determine if the condition we're dealing with is constant 7789 SDValue SCC = SimplifySetCC(TLI.getSetCCResultType(N0.getValueType()), 7790 N0, N1, CC, DL, false); 7791 if (SCC.getNode()) AddToWorkList(SCC.getNode()); 7792 ConstantSDNode *SCCC = dyn_cast_or_null<ConstantSDNode>(SCC.getNode()); 7793 7794 // fold select_cc true, x, y -> x 7795 if (SCCC && !SCCC->isNullValue()) 7796 return N2; 7797 // fold select_cc false, x, y -> y 7798 if (SCCC && SCCC->isNullValue()) 7799 return N3; 7800 7801 // Check to see if we can simplify the select into an fabs node 7802 if (ConstantFPSDNode *CFP = dyn_cast<ConstantFPSDNode>(N1)) { 7803 // Allow either -0.0 or 0.0 7804 if (CFP->getValueAPF().isZero()) { 7805 // select (setg[te] X, +/-0.0), X, fneg(X) -> fabs 7806 if ((CC == ISD::SETGE || CC == ISD::SETGT) && 7807 N0 == N2 && N3.getOpcode() == ISD::FNEG && 7808 N2 == N3.getOperand(0)) 7809 return DAG.getNode(ISD::FABS, DL, VT, N0); 7810 7811 // select (setl[te] X, +/-0.0), fneg(X), X -> fabs 7812 if ((CC == ISD::SETLT || CC == ISD::SETLE) && 7813 N0 == N3 && N2.getOpcode() == ISD::FNEG && 7814 N2.getOperand(0) == N3) 7815 return DAG.getNode(ISD::FABS, DL, VT, N3); 7816 } 7817 } 7818 7819 // Turn "(a cond b) ? 1.0f : 2.0f" into "load (tmp + ((a cond b) ? 0 : 4)" 7820 // where "tmp" is a constant pool entry containing an array with 1.0 and 2.0 7821 // in it. This is a win when the constant is not otherwise available because 7822 // it replaces two constant pool loads with one. We only do this if the FP 7823 // type is known to be legal, because if it isn't, then we are before legalize 7824 // types an we want the other legalization to happen first (e.g. to avoid 7825 // messing with soft float) and if the ConstantFP is not legal, because if 7826 // it is legal, we may not need to store the FP constant in a constant pool. 7827 if (ConstantFPSDNode *TV = dyn_cast<ConstantFPSDNode>(N2)) 7828 if (ConstantFPSDNode *FV = dyn_cast<ConstantFPSDNode>(N3)) { 7829 if (TLI.isTypeLegal(N2.getValueType()) && 7830 (TLI.getOperationAction(ISD::ConstantFP, N2.getValueType()) != 7831 TargetLowering::Legal) && 7832 // If both constants have multiple uses, then we won't need to do an 7833 // extra load, they are likely around in registers for other users. 7834 (TV->hasOneUse() || FV->hasOneUse())) { 7835 Constant *Elts[] = { 7836 const_cast<ConstantFP*>(FV->getConstantFPValue()), 7837 const_cast<ConstantFP*>(TV->getConstantFPValue()) 7838 }; 7839 Type *FPTy = Elts[0]->getType(); 7840 const TargetData &TD = *TLI.getTargetData(); 7841 7842 // Create a ConstantArray of the two constants. 7843 Constant *CA = ConstantArray::get(ArrayType::get(FPTy, 2), Elts); 7844 SDValue CPIdx = DAG.getConstantPool(CA, TLI.getPointerTy(), 7845 TD.getPrefTypeAlignment(FPTy)); 7846 unsigned Alignment = cast<ConstantPoolSDNode>(CPIdx)->getAlignment(); 7847 7848 // Get the offsets to the 0 and 1 element of the array so that we can 7849 // select between them. 7850 SDValue Zero = DAG.getIntPtrConstant(0); 7851 unsigned EltSize = (unsigned)TD.getTypeAllocSize(Elts[0]->getType()); 7852 SDValue One = DAG.getIntPtrConstant(EltSize); 7853 7854 SDValue Cond = DAG.getSetCC(DL, 7855 TLI.getSetCCResultType(N0.getValueType()), 7856 N0, N1, CC); 7857 AddToWorkList(Cond.getNode()); 7858 SDValue CstOffset = DAG.getNode(ISD::SELECT, DL, Zero.getValueType(), 7859 Cond, One, Zero); 7860 AddToWorkList(CstOffset.getNode()); 7861 CPIdx = DAG.getNode(ISD::ADD, DL, TLI.getPointerTy(), CPIdx, 7862 CstOffset); 7863 AddToWorkList(CPIdx.getNode()); 7864 return DAG.getLoad(TV->getValueType(0), DL, DAG.getEntryNode(), CPIdx, 7865 MachinePointerInfo::getConstantPool(), false, 7866 false, false, Alignment); 7867 7868 } 7869 } 7870 7871 // Check to see if we can perform the "gzip trick", transforming 7872 // (select_cc setlt X, 0, A, 0) -> (and (sra X, (sub size(X), 1), A) 7873 if (N1C && N3C && N3C->isNullValue() && CC == ISD::SETLT && 7874 (N1C->isNullValue() || // (a < 0) ? b : 0 7875 (N1C->getAPIntValue() == 1 && N0 == N2))) { // (a < 1) ? a : 0 7876 EVT XType = N0.getValueType(); 7877 EVT AType = N2.getValueType(); 7878 if (XType.bitsGE(AType)) { 7879 // and (sra X, size(X)-1, A) -> "and (srl X, C2), A" iff A is a 7880 // single-bit constant. 7881 if (N2C && ((N2C->getAPIntValue() & (N2C->getAPIntValue()-1)) == 0)) { 7882 unsigned ShCtV = N2C->getAPIntValue().logBase2(); 7883 ShCtV = XType.getSizeInBits()-ShCtV-1; 7884 SDValue ShCt = DAG.getConstant(ShCtV, 7885 getShiftAmountTy(N0.getValueType())); 7886 SDValue Shift = DAG.getNode(ISD::SRL, N0.getDebugLoc(), 7887 XType, N0, ShCt); 7888 AddToWorkList(Shift.getNode()); 7889 7890 if (XType.bitsGT(AType)) { 7891 Shift = DAG.getNode(ISD::TRUNCATE, DL, AType, Shift); 7892 AddToWorkList(Shift.getNode()); 7893 } 7894 7895 return DAG.getNode(ISD::AND, DL, AType, Shift, N2); 7896 } 7897 7898 SDValue Shift = DAG.getNode(ISD::SRA, N0.getDebugLoc(), 7899 XType, N0, 7900 DAG.getConstant(XType.getSizeInBits()-1, 7901 getShiftAmountTy(N0.getValueType()))); 7902 AddToWorkList(Shift.getNode()); 7903 7904 if (XType.bitsGT(AType)) { 7905 Shift = DAG.getNode(ISD::TRUNCATE, DL, AType, Shift); 7906 AddToWorkList(Shift.getNode()); 7907 } 7908 7909 return DAG.getNode(ISD::AND, DL, AType, Shift, N2); 7910 } 7911 } 7912 7913 // fold (select_cc seteq (and x, y), 0, 0, A) -> (and (shr (shl x)) A) 7914 // where y is has a single bit set. 7915 // A plaintext description would be, we can turn the SELECT_CC into an AND 7916 // when the condition can be materialized as an all-ones register. Any 7917 // single bit-test can be materialized as an all-ones register with 7918 // shift-left and shift-right-arith. 7919 if (CC == ISD::SETEQ && N0->getOpcode() == ISD::AND && 7920 N0->getValueType(0) == VT && 7921 N1C && N1C->isNullValue() && 7922 N2C && N2C->isNullValue()) { 7923 SDValue AndLHS = N0->getOperand(0); 7924 ConstantSDNode *ConstAndRHS = dyn_cast<ConstantSDNode>(N0->getOperand(1)); 7925 if (ConstAndRHS && ConstAndRHS->getAPIntValue().countPopulation() == 1) { 7926 // Shift the tested bit over the sign bit. 7927 APInt AndMask = ConstAndRHS->getAPIntValue(); 7928 SDValue ShlAmt = 7929 DAG.getConstant(AndMask.countLeadingZeros(), 7930 getShiftAmountTy(AndLHS.getValueType())); 7931 SDValue Shl = DAG.getNode(ISD::SHL, N0.getDebugLoc(), VT, AndLHS, ShlAmt); 7932 7933 // Now arithmetic right shift it all the way over, so the result is either 7934 // all-ones, or zero. 7935 SDValue ShrAmt = 7936 DAG.getConstant(AndMask.getBitWidth()-1, 7937 getShiftAmountTy(Shl.getValueType())); 7938 SDValue Shr = DAG.getNode(ISD::SRA, N0.getDebugLoc(), VT, Shl, ShrAmt); 7939 7940 return DAG.getNode(ISD::AND, DL, VT, Shr, N3); 7941 } 7942 } 7943 7944 // fold select C, 16, 0 -> shl C, 4 7945 if (N2C && N3C && N3C->isNullValue() && N2C->getAPIntValue().isPowerOf2() && 7946 TLI.getBooleanContents(N0.getValueType().isVector()) == 7947 TargetLowering::ZeroOrOneBooleanContent) { 7948 7949 // If the caller doesn't want us to simplify this into a zext of a compare, 7950 // don't do it. 7951 if (NotExtCompare && N2C->getAPIntValue() == 1) 7952 return SDValue(); 7953 7954 // Get a SetCC of the condition 7955 // FIXME: Should probably make sure that setcc is legal if we ever have a 7956 // target where it isn't. 7957 SDValue Temp, SCC; 7958 // cast from setcc result type to select result type 7959 if (LegalTypes) { 7960 SCC = DAG.getSetCC(DL, TLI.getSetCCResultType(N0.getValueType()), 7961 N0, N1, CC); 7962 if (N2.getValueType().bitsLT(SCC.getValueType())) 7963 Temp = DAG.getZeroExtendInReg(SCC, N2.getDebugLoc(), N2.getValueType()); 7964 else 7965 Temp = DAG.getNode(ISD::ZERO_EXTEND, N2.getDebugLoc(), 7966 N2.getValueType(), SCC); 7967 } else { 7968 SCC = DAG.getSetCC(N0.getDebugLoc(), MVT::i1, N0, N1, CC); 7969 Temp = DAG.getNode(ISD::ZERO_EXTEND, N2.getDebugLoc(), 7970 N2.getValueType(), SCC); 7971 } 7972 7973 AddToWorkList(SCC.getNode()); 7974 AddToWorkList(Temp.getNode()); 7975 7976 if (N2C->getAPIntValue() == 1) 7977 return Temp; 7978 7979 // shl setcc result by log2 n2c 7980 return DAG.getNode(ISD::SHL, DL, N2.getValueType(), Temp, 7981 DAG.getConstant(N2C->getAPIntValue().logBase2(), 7982 getShiftAmountTy(Temp.getValueType()))); 7983 } 7984 7985 // Check to see if this is the equivalent of setcc 7986 // FIXME: Turn all of these into setcc if setcc if setcc is legal 7987 // otherwise, go ahead with the folds. 7988 if (0 && N3C && N3C->isNullValue() && N2C && (N2C->getAPIntValue() == 1ULL)) { 7989 EVT XType = N0.getValueType(); 7990 if (!LegalOperations || 7991 TLI.isOperationLegal(ISD::SETCC, TLI.getSetCCResultType(XType))) { 7992 SDValue Res = DAG.getSetCC(DL, TLI.getSetCCResultType(XType), N0, N1, CC); 7993 if (Res.getValueType() != VT) 7994 Res = DAG.getNode(ISD::ZERO_EXTEND, DL, VT, Res); 7995 return Res; 7996 } 7997 7998 // fold (seteq X, 0) -> (srl (ctlz X, log2(size(X)))) 7999 if (N1C && N1C->isNullValue() && CC == ISD::SETEQ && 8000 (!LegalOperations || 8001 TLI.isOperationLegal(ISD::CTLZ, XType))) { 8002 SDValue Ctlz = DAG.getNode(ISD::CTLZ, N0.getDebugLoc(), XType, N0); 8003 return DAG.getNode(ISD::SRL, DL, XType, Ctlz, 8004 DAG.getConstant(Log2_32(XType.getSizeInBits()), 8005 getShiftAmountTy(Ctlz.getValueType()))); 8006 } 8007 // fold (setgt X, 0) -> (srl (and (-X, ~X), size(X)-1)) 8008 if (N1C && N1C->isNullValue() && CC == ISD::SETGT) { 8009 SDValue NegN0 = DAG.getNode(ISD::SUB, N0.getDebugLoc(), 8010 XType, DAG.getConstant(0, XType), N0); 8011 SDValue NotN0 = DAG.getNOT(N0.getDebugLoc(), N0, XType); 8012 return DAG.getNode(ISD::SRL, DL, XType, 8013 DAG.getNode(ISD::AND, DL, XType, NegN0, NotN0), 8014 DAG.getConstant(XType.getSizeInBits()-1, 8015 getShiftAmountTy(XType))); 8016 } 8017 // fold (setgt X, -1) -> (xor (srl (X, size(X)-1), 1)) 8018 if (N1C && N1C->isAllOnesValue() && CC == ISD::SETGT) { 8019 SDValue Sign = DAG.getNode(ISD::SRL, N0.getDebugLoc(), XType, N0, 8020 DAG.getConstant(XType.getSizeInBits()-1, 8021 getShiftAmountTy(N0.getValueType()))); 8022 return DAG.getNode(ISD::XOR, DL, XType, Sign, DAG.getConstant(1, XType)); 8023 } 8024 } 8025 8026 // Check to see if this is an integer abs. 8027 // select_cc setg[te] X, 0, X, -X -> 8028 // select_cc setgt X, -1, X, -X -> 8029 // select_cc setl[te] X, 0, -X, X -> 8030 // select_cc setlt X, 1, -X, X -> 8031 // Y = sra (X, size(X)-1); xor (add (X, Y), Y) 8032 if (N1C) { 8033 ConstantSDNode *SubC = NULL; 8034 if (((N1C->isNullValue() && (CC == ISD::SETGT || CC == ISD::SETGE)) || 8035 (N1C->isAllOnesValue() && CC == ISD::SETGT)) && 8036 N0 == N2 && N3.getOpcode() == ISD::SUB && N0 == N3.getOperand(1)) 8037 SubC = dyn_cast<ConstantSDNode>(N3.getOperand(0)); 8038 else if (((N1C->isNullValue() && (CC == ISD::SETLT || CC == ISD::SETLE)) || 8039 (N1C->isOne() && CC == ISD::SETLT)) && 8040 N0 == N3 && N2.getOpcode() == ISD::SUB && N0 == N2.getOperand(1)) 8041 SubC = dyn_cast<ConstantSDNode>(N2.getOperand(0)); 8042 8043 EVT XType = N0.getValueType(); 8044 if (SubC && SubC->isNullValue() && XType.isInteger()) { 8045 SDValue Shift = DAG.getNode(ISD::SRA, N0.getDebugLoc(), XType, 8046 N0, 8047 DAG.getConstant(XType.getSizeInBits()-1, 8048 getShiftAmountTy(N0.getValueType()))); 8049 SDValue Add = DAG.getNode(ISD::ADD, N0.getDebugLoc(), 8050 XType, N0, Shift); 8051 AddToWorkList(Shift.getNode()); 8052 AddToWorkList(Add.getNode()); 8053 return DAG.getNode(ISD::XOR, DL, XType, Add, Shift); 8054 } 8055 } 8056 8057 return SDValue(); 8058} 8059 8060/// SimplifySetCC - This is a stub for TargetLowering::SimplifySetCC. 8061SDValue DAGCombiner::SimplifySetCC(EVT VT, SDValue N0, 8062 SDValue N1, ISD::CondCode Cond, 8063 DebugLoc DL, bool foldBooleans) { 8064 TargetLowering::DAGCombinerInfo 8065 DagCombineInfo(DAG, !LegalTypes, !LegalOperations, false, this); 8066 return TLI.SimplifySetCC(VT, N0, N1, Cond, foldBooleans, DagCombineInfo, DL); 8067} 8068 8069/// BuildSDIVSequence - Given an ISD::SDIV node expressing a divide by constant, 8070/// return a DAG expression to select that will generate the same value by 8071/// multiplying by a magic number. See: 8072/// <http://the.wall.riscom.net/books/proc/ppc/cwg/code2.html> 8073SDValue DAGCombiner::BuildSDIV(SDNode *N) { 8074 std::vector<SDNode*> Built; 8075 SDValue S = TLI.BuildSDIV(N, DAG, LegalOperations, &Built); 8076 8077 for (std::vector<SDNode*>::iterator ii = Built.begin(), ee = Built.end(); 8078 ii != ee; ++ii) 8079 AddToWorkList(*ii); 8080 return S; 8081} 8082 8083/// BuildUDIVSequence - Given an ISD::UDIV node expressing a divide by constant, 8084/// return a DAG expression to select that will generate the same value by 8085/// multiplying by a magic number. See: 8086/// <http://the.wall.riscom.net/books/proc/ppc/cwg/code2.html> 8087SDValue DAGCombiner::BuildUDIV(SDNode *N) { 8088 std::vector<SDNode*> Built; 8089 SDValue S = TLI.BuildUDIV(N, DAG, LegalOperations, &Built); 8090 8091 for (std::vector<SDNode*>::iterator ii = Built.begin(), ee = Built.end(); 8092 ii != ee; ++ii) 8093 AddToWorkList(*ii); 8094 return S; 8095} 8096 8097/// FindBaseOffset - Return true if base is a frame index, which is known not 8098// to alias with anything but itself. Provides base object and offset as 8099// results. 8100static bool FindBaseOffset(SDValue Ptr, SDValue &Base, int64_t &Offset, 8101 const GlobalValue *&GV, void *&CV) { 8102 // Assume it is a primitive operation. 8103 Base = Ptr; Offset = 0; GV = 0; CV = 0; 8104 8105 // If it's an adding a simple constant then integrate the offset. 8106 if (Base.getOpcode() == ISD::ADD) { 8107 if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Base.getOperand(1))) { 8108 Base = Base.getOperand(0); 8109 Offset += C->getZExtValue(); 8110 } 8111 } 8112 8113 // Return the underlying GlobalValue, and update the Offset. Return false 8114 // for GlobalAddressSDNode since the same GlobalAddress may be represented 8115 // by multiple nodes with different offsets. 8116 if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Base)) { 8117 GV = G->getGlobal(); 8118 Offset += G->getOffset(); 8119 return false; 8120 } 8121 8122 // Return the underlying Constant value, and update the Offset. Return false 8123 // for ConstantSDNodes since the same constant pool entry may be represented 8124 // by multiple nodes with different offsets. 8125 if (ConstantPoolSDNode *C = dyn_cast<ConstantPoolSDNode>(Base)) { 8126 CV = C->isMachineConstantPoolEntry() ? (void *)C->getMachineCPVal() 8127 : (void *)C->getConstVal(); 8128 Offset += C->getOffset(); 8129 return false; 8130 } 8131 // If it's any of the following then it can't alias with anything but itself. 8132 return isa<FrameIndexSDNode>(Base); 8133} 8134 8135/// isAlias - Return true if there is any possibility that the two addresses 8136/// overlap. 8137bool DAGCombiner::isAlias(SDValue Ptr1, int64_t Size1, 8138 const Value *SrcValue1, int SrcValueOffset1, 8139 unsigned SrcValueAlign1, 8140 const MDNode *TBAAInfo1, 8141 SDValue Ptr2, int64_t Size2, 8142 const Value *SrcValue2, int SrcValueOffset2, 8143 unsigned SrcValueAlign2, 8144 const MDNode *TBAAInfo2) const { 8145 // If they are the same then they must be aliases. 8146 if (Ptr1 == Ptr2) return true; 8147 8148 // Gather base node and offset information. 8149 SDValue Base1, Base2; 8150 int64_t Offset1, Offset2; 8151 const GlobalValue *GV1, *GV2; 8152 void *CV1, *CV2; 8153 bool isFrameIndex1 = FindBaseOffset(Ptr1, Base1, Offset1, GV1, CV1); 8154 bool isFrameIndex2 = FindBaseOffset(Ptr2, Base2, Offset2, GV2, CV2); 8155 8156 // If they have a same base address then check to see if they overlap. 8157 if (Base1 == Base2 || (GV1 && (GV1 == GV2)) || (CV1 && (CV1 == CV2))) 8158 return !((Offset1 + Size1) <= Offset2 || (Offset2 + Size2) <= Offset1); 8159 8160 // It is possible for different frame indices to alias each other, mostly 8161 // when tail call optimization reuses return address slots for arguments. 8162 // To catch this case, look up the actual index of frame indices to compute 8163 // the real alias relationship. 8164 if (isFrameIndex1 && isFrameIndex2) { 8165 MachineFrameInfo *MFI = DAG.getMachineFunction().getFrameInfo(); 8166 Offset1 += MFI->getObjectOffset(cast<FrameIndexSDNode>(Base1)->getIndex()); 8167 Offset2 += MFI->getObjectOffset(cast<FrameIndexSDNode>(Base2)->getIndex()); 8168 return !((Offset1 + Size1) <= Offset2 || (Offset2 + Size2) <= Offset1); 8169 } 8170 8171 // Otherwise, if we know what the bases are, and they aren't identical, then 8172 // we know they cannot alias. 8173 if ((isFrameIndex1 || CV1 || GV1) && (isFrameIndex2 || CV2 || GV2)) 8174 return false; 8175 8176 // If we know required SrcValue1 and SrcValue2 have relatively large alignment 8177 // compared to the size and offset of the access, we may be able to prove they 8178 // do not alias. This check is conservative for now to catch cases created by 8179 // splitting vector types. 8180 if ((SrcValueAlign1 == SrcValueAlign2) && 8181 (SrcValueOffset1 != SrcValueOffset2) && 8182 (Size1 == Size2) && (SrcValueAlign1 > Size1)) { 8183 int64_t OffAlign1 = SrcValueOffset1 % SrcValueAlign1; 8184 int64_t OffAlign2 = SrcValueOffset2 % SrcValueAlign1; 8185 8186 // There is no overlap between these relatively aligned accesses of similar 8187 // size, return no alias. 8188 if ((OffAlign1 + Size1) <= OffAlign2 || (OffAlign2 + Size2) <= OffAlign1) 8189 return false; 8190 } 8191 8192 if (CombinerGlobalAA) { 8193 // Use alias analysis information. 8194 int64_t MinOffset = std::min(SrcValueOffset1, SrcValueOffset2); 8195 int64_t Overlap1 = Size1 + SrcValueOffset1 - MinOffset; 8196 int64_t Overlap2 = Size2 + SrcValueOffset2 - MinOffset; 8197 AliasAnalysis::AliasResult AAResult = 8198 AA.alias(AliasAnalysis::Location(SrcValue1, Overlap1, TBAAInfo1), 8199 AliasAnalysis::Location(SrcValue2, Overlap2, TBAAInfo2)); 8200 if (AAResult == AliasAnalysis::NoAlias) 8201 return false; 8202 } 8203 8204 // Otherwise we have to assume they alias. 8205 return true; 8206} 8207 8208/// FindAliasInfo - Extracts the relevant alias information from the memory 8209/// node. Returns true if the operand was a load. 8210bool DAGCombiner::FindAliasInfo(SDNode *N, 8211 SDValue &Ptr, int64_t &Size, 8212 const Value *&SrcValue, 8213 int &SrcValueOffset, 8214 unsigned &SrcValueAlign, 8215 const MDNode *&TBAAInfo) const { 8216 LSBaseSDNode *LS = cast<LSBaseSDNode>(N); 8217 8218 Ptr = LS->getBasePtr(); 8219 Size = LS->getMemoryVT().getSizeInBits() >> 3; 8220 SrcValue = LS->getSrcValue(); 8221 SrcValueOffset = LS->getSrcValueOffset(); 8222 SrcValueAlign = LS->getOriginalAlignment(); 8223 TBAAInfo = LS->getTBAAInfo(); 8224 return isa<LoadSDNode>(LS); 8225} 8226 8227/// GatherAllAliases - Walk up chain skipping non-aliasing memory nodes, 8228/// looking for aliasing nodes and adding them to the Aliases vector. 8229void DAGCombiner::GatherAllAliases(SDNode *N, SDValue OriginalChain, 8230 SmallVector<SDValue, 8> &Aliases) { 8231 SmallVector<SDValue, 8> Chains; // List of chains to visit. 8232 SmallPtrSet<SDNode *, 16> Visited; // Visited node set. 8233 8234 // Get alias information for node. 8235 SDValue Ptr; 8236 int64_t Size; 8237 const Value *SrcValue; 8238 int SrcValueOffset; 8239 unsigned SrcValueAlign; 8240 const MDNode *SrcTBAAInfo; 8241 bool IsLoad = FindAliasInfo(N, Ptr, Size, SrcValue, SrcValueOffset, 8242 SrcValueAlign, SrcTBAAInfo); 8243 8244 // Starting off. 8245 Chains.push_back(OriginalChain); 8246 unsigned Depth = 0; 8247 8248 // Look at each chain and determine if it is an alias. If so, add it to the 8249 // aliases list. If not, then continue up the chain looking for the next 8250 // candidate. 8251 while (!Chains.empty()) { 8252 SDValue Chain = Chains.back(); 8253 Chains.pop_back(); 8254 8255 // For TokenFactor nodes, look at each operand and only continue up the 8256 // chain until we find two aliases. If we've seen two aliases, assume we'll 8257 // find more and revert to original chain since the xform is unlikely to be 8258 // profitable. 8259 // 8260 // FIXME: The depth check could be made to return the last non-aliasing 8261 // chain we found before we hit a tokenfactor rather than the original 8262 // chain. 8263 if (Depth > 6 || Aliases.size() == 2) { 8264 Aliases.clear(); 8265 Aliases.push_back(OriginalChain); 8266 break; 8267 } 8268 8269 // Don't bother if we've been before. 8270 if (!Visited.insert(Chain.getNode())) 8271 continue; 8272 8273 switch (Chain.getOpcode()) { 8274 case ISD::EntryToken: 8275 // Entry token is ideal chain operand, but handled in FindBetterChain. 8276 break; 8277 8278 case ISD::LOAD: 8279 case ISD::STORE: { 8280 // Get alias information for Chain. 8281 SDValue OpPtr; 8282 int64_t OpSize; 8283 const Value *OpSrcValue; 8284 int OpSrcValueOffset; 8285 unsigned OpSrcValueAlign; 8286 const MDNode *OpSrcTBAAInfo; 8287 bool IsOpLoad = FindAliasInfo(Chain.getNode(), OpPtr, OpSize, 8288 OpSrcValue, OpSrcValueOffset, 8289 OpSrcValueAlign, 8290 OpSrcTBAAInfo); 8291 8292 // If chain is alias then stop here. 8293 if (!(IsLoad && IsOpLoad) && 8294 isAlias(Ptr, Size, SrcValue, SrcValueOffset, SrcValueAlign, 8295 SrcTBAAInfo, 8296 OpPtr, OpSize, OpSrcValue, OpSrcValueOffset, 8297 OpSrcValueAlign, OpSrcTBAAInfo)) { 8298 Aliases.push_back(Chain); 8299 } else { 8300 // Look further up the chain. 8301 Chains.push_back(Chain.getOperand(0)); 8302 ++Depth; 8303 } 8304 break; 8305 } 8306 8307 case ISD::TokenFactor: 8308 // We have to check each of the operands of the token factor for "small" 8309 // token factors, so we queue them up. Adding the operands to the queue 8310 // (stack) in reverse order maintains the original order and increases the 8311 // likelihood that getNode will find a matching token factor (CSE.) 8312 if (Chain.getNumOperands() > 16) { 8313 Aliases.push_back(Chain); 8314 break; 8315 } 8316 for (unsigned n = Chain.getNumOperands(); n;) 8317 Chains.push_back(Chain.getOperand(--n)); 8318 ++Depth; 8319 break; 8320 8321 default: 8322 // For all other instructions we will just have to take what we can get. 8323 Aliases.push_back(Chain); 8324 break; 8325 } 8326 } 8327} 8328 8329/// FindBetterChain - Walk up chain skipping non-aliasing memory nodes, looking 8330/// for a better chain (aliasing node.) 8331SDValue DAGCombiner::FindBetterChain(SDNode *N, SDValue OldChain) { 8332 SmallVector<SDValue, 8> Aliases; // Ops for replacing token factor. 8333 8334 // Accumulate all the aliases to this node. 8335 GatherAllAliases(N, OldChain, Aliases); 8336 8337 // If no operands then chain to entry token. 8338 if (Aliases.size() == 0) 8339 return DAG.getEntryNode(); 8340 8341 // If a single operand then chain to it. We don't need to revisit it. 8342 if (Aliases.size() == 1) 8343 return Aliases[0]; 8344 8345 // Construct a custom tailored token factor. 8346 return DAG.getNode(ISD::TokenFactor, N->getDebugLoc(), MVT::Other, 8347 &Aliases[0], Aliases.size()); 8348} 8349 8350// SelectionDAG::Combine - This is the entry point for the file. 8351// 8352void SelectionDAG::Combine(CombineLevel Level, AliasAnalysis &AA, 8353 CodeGenOpt::Level OptLevel) { 8354 /// run - This is the main entry point to this class. 8355 /// 8356 DAGCombiner(*this, AA, OptLevel).Run(Level); 8357} 8358