DAGCombiner.cpp revision e0f06c78d3ee56cea4e7195c616aafc200cb0ba2
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/CodeGen/PseudoSourceValue.h" 26#include "llvm/Analysis/AliasAnalysis.h" 27#include "llvm/Target/TargetData.h" 28#include "llvm/Target/TargetFrameInfo.h" 29#include "llvm/Target/TargetLowering.h" 30#include "llvm/Target/TargetMachine.h" 31#include "llvm/Target/TargetOptions.h" 32#include "llvm/ADT/SmallPtrSet.h" 33#include "llvm/ADT/Statistic.h" 34#include "llvm/Support/CommandLine.h" 35#include "llvm/Support/Debug.h" 36#include "llvm/Support/ErrorHandling.h" 37#include "llvm/Support/MathExtras.h" 38#include "llvm/Support/raw_ostream.h" 39#include <algorithm> 40using namespace llvm; 41 42STATISTIC(NodesCombined , "Number of dag nodes combined"); 43STATISTIC(PreIndexedNodes , "Number of pre-indexed nodes created"); 44STATISTIC(PostIndexedNodes, "Number of post-indexed nodes created"); 45STATISTIC(OpsNarrowed , "Number of load/op/store narrowed"); 46 47namespace { 48 static cl::opt<bool> 49 CombinerAA("combiner-alias-analysis", cl::Hidden, 50 cl::desc("Turn on alias analysis during testing")); 51 52 static cl::opt<bool> 53 CombinerGlobalAA("combiner-global-alias-analysis", cl::Hidden, 54 cl::desc("Include global information in alias analysis")); 55 56//------------------------------ DAGCombiner ---------------------------------// 57 58 class DAGCombiner { 59 SelectionDAG &DAG; 60 const TargetLowering &TLI; 61 CombineLevel Level; 62 CodeGenOpt::Level OptLevel; 63 bool LegalOperations; 64 bool LegalTypes; 65 66 // Worklist of all of the nodes that need to be simplified. 67 std::vector<SDNode*> WorkList; 68 69 // AA - Used for DAG load/store alias analysis. 70 AliasAnalysis &AA; 71 72 /// AddUsersToWorkList - When an instruction is simplified, add all users of 73 /// the instruction to the work lists because they might get more simplified 74 /// now. 75 /// 76 void AddUsersToWorkList(SDNode *N) { 77 for (SDNode::use_iterator UI = N->use_begin(), UE = N->use_end(); 78 UI != UE; ++UI) 79 AddToWorkList(*UI); 80 } 81 82 /// visit - call the node-specific routine that knows how to fold each 83 /// particular type of node. 84 SDValue visit(SDNode *N); 85 86 public: 87 /// AddToWorkList - Add to the work list making sure it's instance is at the 88 /// the back (next to be processed.) 89 void AddToWorkList(SDNode *N) { 90 removeFromWorkList(N); 91 WorkList.push_back(N); 92 } 93 94 /// removeFromWorkList - remove all instances of N from the worklist. 95 /// 96 void removeFromWorkList(SDNode *N) { 97 WorkList.erase(std::remove(WorkList.begin(), WorkList.end(), N), 98 WorkList.end()); 99 } 100 101 SDValue CombineTo(SDNode *N, const SDValue *To, unsigned NumTo, 102 bool AddTo = true); 103 104 SDValue CombineTo(SDNode *N, SDValue Res, bool AddTo = true) { 105 return CombineTo(N, &Res, 1, AddTo); 106 } 107 108 SDValue CombineTo(SDNode *N, SDValue Res0, SDValue Res1, 109 bool AddTo = true) { 110 SDValue To[] = { Res0, Res1 }; 111 return CombineTo(N, To, 2, AddTo); 112 } 113 114 void CommitTargetLoweringOpt(const TargetLowering::TargetLoweringOpt &TLO); 115 116 private: 117 118 /// SimplifyDemandedBits - Check the specified integer node value to see if 119 /// it can be simplified or if things it uses can be simplified by bit 120 /// propagation. If so, return true. 121 bool SimplifyDemandedBits(SDValue Op) { 122 APInt Demanded = APInt::getAllOnesValue(Op.getValueSizeInBits()); 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); 130 131 132 /// combine - call the node-specific routine that knows how to fold each 133 /// particular type of node. If that doesn't do anything, try the 134 /// target-specific DAG combines. 135 SDValue combine(SDNode *N); 136 137 // Visitation implementation - Implement dag node combining for different 138 // node types. The semantics are as follows: 139 // Return Value: 140 // SDValue.getNode() == 0 - No change was made 141 // SDValue.getNode() == N - N was replaced, is dead and has been handled. 142 // otherwise - N should be replaced by the returned Operand. 143 // 144 SDValue visitTokenFactor(SDNode *N); 145 SDValue visitMERGE_VALUES(SDNode *N); 146 SDValue visitADD(SDNode *N); 147 SDValue visitSUB(SDNode *N); 148 SDValue visitADDC(SDNode *N); 149 SDValue visitADDE(SDNode *N); 150 SDValue visitMUL(SDNode *N); 151 SDValue visitSDIV(SDNode *N); 152 SDValue visitUDIV(SDNode *N); 153 SDValue visitSREM(SDNode *N); 154 SDValue visitUREM(SDNode *N); 155 SDValue visitMULHU(SDNode *N); 156 SDValue visitMULHS(SDNode *N); 157 SDValue visitSMUL_LOHI(SDNode *N); 158 SDValue visitUMUL_LOHI(SDNode *N); 159 SDValue visitSDIVREM(SDNode *N); 160 SDValue visitUDIVREM(SDNode *N); 161 SDValue visitAND(SDNode *N); 162 SDValue visitOR(SDNode *N); 163 SDValue visitXOR(SDNode *N); 164 SDValue SimplifyVBinOp(SDNode *N); 165 SDValue visitSHL(SDNode *N); 166 SDValue visitSRA(SDNode *N); 167 SDValue visitSRL(SDNode *N); 168 SDValue visitCTLZ(SDNode *N); 169 SDValue visitCTTZ(SDNode *N); 170 SDValue visitCTPOP(SDNode *N); 171 SDValue visitSELECT(SDNode *N); 172 SDValue visitSELECT_CC(SDNode *N); 173 SDValue visitSETCC(SDNode *N); 174 SDValue visitSIGN_EXTEND(SDNode *N); 175 SDValue visitZERO_EXTEND(SDNode *N); 176 SDValue visitANY_EXTEND(SDNode *N); 177 SDValue visitSIGN_EXTEND_INREG(SDNode *N); 178 SDValue visitTRUNCATE(SDNode *N); 179 SDValue visitBIT_CONVERT(SDNode *N); 180 SDValue visitBUILD_PAIR(SDNode *N); 181 SDValue visitFADD(SDNode *N); 182 SDValue visitFSUB(SDNode *N); 183 SDValue visitFMUL(SDNode *N); 184 SDValue visitFDIV(SDNode *N); 185 SDValue visitFREM(SDNode *N); 186 SDValue visitFCOPYSIGN(SDNode *N); 187 SDValue visitSINT_TO_FP(SDNode *N); 188 SDValue visitUINT_TO_FP(SDNode *N); 189 SDValue visitFP_TO_SINT(SDNode *N); 190 SDValue visitFP_TO_UINT(SDNode *N); 191 SDValue visitFP_ROUND(SDNode *N); 192 SDValue visitFP_ROUND_INREG(SDNode *N); 193 SDValue visitFP_EXTEND(SDNode *N); 194 SDValue visitFNEG(SDNode *N); 195 SDValue visitFABS(SDNode *N); 196 SDValue visitBRCOND(SDNode *N); 197 SDValue visitBR_CC(SDNode *N); 198 SDValue visitLOAD(SDNode *N); 199 SDValue visitSTORE(SDNode *N); 200 SDValue visitINSERT_VECTOR_ELT(SDNode *N); 201 SDValue visitEXTRACT_VECTOR_ELT(SDNode *N); 202 SDValue visitBUILD_VECTOR(SDNode *N); 203 SDValue visitCONCAT_VECTORS(SDNode *N); 204 SDValue visitVECTOR_SHUFFLE(SDNode *N); 205 206 SDValue XformToShuffleWithZero(SDNode *N); 207 SDValue ReassociateOps(unsigned Opc, DebugLoc DL, SDValue LHS, SDValue RHS); 208 209 SDValue visitShiftByConstant(SDNode *N, unsigned Amt); 210 211 bool SimplifySelectOps(SDNode *SELECT, SDValue LHS, SDValue RHS); 212 SDValue SimplifyBinOpWithSameOpcodeHands(SDNode *N); 213 SDValue SimplifySelect(DebugLoc DL, SDValue N0, SDValue N1, SDValue N2); 214 SDValue SimplifySelectCC(DebugLoc DL, SDValue N0, SDValue N1, SDValue N2, 215 SDValue N3, ISD::CondCode CC, 216 bool NotExtCompare = false); 217 SDValue SimplifySetCC(EVT VT, SDValue N0, SDValue N1, ISD::CondCode Cond, 218 DebugLoc DL, bool foldBooleans = true); 219 SDValue SimplifyNodeWithTwoResults(SDNode *N, unsigned LoOp, 220 unsigned HiOp); 221 SDValue CombineConsecutiveLoads(SDNode *N, EVT VT); 222 SDValue ConstantFoldBIT_CONVERTofBUILD_VECTOR(SDNode *, EVT); 223 SDValue BuildSDIV(SDNode *N); 224 SDValue BuildUDIV(SDNode *N); 225 SDNode *MatchRotate(SDValue LHS, SDValue RHS, DebugLoc DL); 226 SDValue ReduceLoadWidth(SDNode *N); 227 SDValue ReduceLoadOpStoreWidth(SDNode *N); 228 229 SDValue GetDemandedBits(SDValue V, const APInt &Mask); 230 231 /// GatherAllAliases - Walk up chain skipping non-aliasing memory nodes, 232 /// looking for aliasing nodes and adding them to the Aliases vector. 233 void GatherAllAliases(SDNode *N, SDValue OriginalChain, 234 SmallVector<SDValue, 8> &Aliases); 235 236 /// isAlias - Return true if there is any possibility that the two addresses 237 /// overlap. 238 bool isAlias(SDValue Ptr1, int64_t Size1, 239 const Value *SrcValue1, int SrcValueOffset1, 240 unsigned SrcValueAlign1, 241 SDValue Ptr2, int64_t Size2, 242 const Value *SrcValue2, int SrcValueOffset2, 243 unsigned SrcValueAlign2) const; 244 245 /// FindAliasInfo - Extracts the relevant alias information from the memory 246 /// node. Returns true if the operand was a load. 247 bool FindAliasInfo(SDNode *N, 248 SDValue &Ptr, int64_t &Size, 249 const Value *&SrcValue, int &SrcValueOffset, 250 unsigned &SrcValueAlignment) const; 251 252 /// FindBetterChain - Walk up chain skipping non-aliasing memory nodes, 253 /// looking for a better chain (aliasing node.) 254 SDValue FindBetterChain(SDNode *N, SDValue Chain); 255 256 /// getShiftAmountTy - Returns a type large enough to hold any valid 257 /// shift amount - before type legalization these can be huge. 258 EVT getShiftAmountTy() { 259 return LegalTypes ? TLI.getShiftAmountTy() : TLI.getPointerTy(); 260 } 261 262public: 263 DAGCombiner(SelectionDAG &D, AliasAnalysis &A, CodeGenOpt::Level OL) 264 : DAG(D), 265 TLI(D.getTargetLoweringInfo()), 266 Level(Unrestricted), 267 OptLevel(OL), 268 LegalOperations(false), 269 LegalTypes(false), 270 AA(A) {} 271 272 /// Run - runs the dag combiner on all nodes in the work list 273 void Run(CombineLevel AtLevel); 274 }; 275} 276 277 278namespace { 279/// WorkListRemover - This class is a DAGUpdateListener that removes any deleted 280/// nodes from the worklist. 281class WorkListRemover : public SelectionDAG::DAGUpdateListener { 282 DAGCombiner &DC; 283public: 284 explicit WorkListRemover(DAGCombiner &dc) : DC(dc) {} 285 286 virtual void NodeDeleted(SDNode *N, SDNode *E) { 287 DC.removeFromWorkList(N); 288 } 289 290 virtual void NodeUpdated(SDNode *N) { 291 // Ignore updates. 292 } 293}; 294} 295 296//===----------------------------------------------------------------------===// 297// TargetLowering::DAGCombinerInfo implementation 298//===----------------------------------------------------------------------===// 299 300void TargetLowering::DAGCombinerInfo::AddToWorklist(SDNode *N) { 301 ((DAGCombiner*)DC)->AddToWorkList(N); 302} 303 304SDValue TargetLowering::DAGCombinerInfo:: 305CombineTo(SDNode *N, const std::vector<SDValue> &To, bool AddTo) { 306 return ((DAGCombiner*)DC)->CombineTo(N, &To[0], To.size(), AddTo); 307} 308 309SDValue TargetLowering::DAGCombinerInfo:: 310CombineTo(SDNode *N, SDValue Res, bool AddTo) { 311 return ((DAGCombiner*)DC)->CombineTo(N, Res, AddTo); 312} 313 314 315SDValue TargetLowering::DAGCombinerInfo:: 316CombineTo(SDNode *N, SDValue Res0, SDValue Res1, bool AddTo) { 317 return ((DAGCombiner*)DC)->CombineTo(N, Res0, Res1, AddTo); 318} 319 320void TargetLowering::DAGCombinerInfo:: 321CommitTargetLoweringOpt(const TargetLowering::TargetLoweringOpt &TLO) { 322 return ((DAGCombiner*)DC)->CommitTargetLoweringOpt(TLO); 323} 324 325//===----------------------------------------------------------------------===// 326// Helper Functions 327//===----------------------------------------------------------------------===// 328 329/// isNegatibleForFree - Return 1 if we can compute the negated form of the 330/// specified expression for the same cost as the expression itself, or 2 if we 331/// can compute the negated form more cheaply than the expression itself. 332static char isNegatibleForFree(SDValue Op, bool LegalOperations, 333 unsigned Depth = 0) { 334 // No compile time optimizations on this type. 335 if (Op.getValueType() == MVT::ppcf128) 336 return 0; 337 338 // fneg is removable even if it has multiple uses. 339 if (Op.getOpcode() == ISD::FNEG) return 2; 340 341 // Don't allow anything with multiple uses. 342 if (!Op.hasOneUse()) return 0; 343 344 // Don't recurse exponentially. 345 if (Depth > 6) return 0; 346 347 switch (Op.getOpcode()) { 348 default: return false; 349 case ISD::ConstantFP: 350 // Don't invert constant FP values after legalize. The negated constant 351 // isn't necessarily legal. 352 return LegalOperations ? 0 : 1; 353 case ISD::FADD: 354 // FIXME: determine better conditions for this xform. 355 if (!UnsafeFPMath) return 0; 356 357 // fold (fsub (fadd A, B)) -> (fsub (fneg A), B) 358 if (char V = isNegatibleForFree(Op.getOperand(0), LegalOperations, Depth+1)) 359 return V; 360 // fold (fneg (fadd A, B)) -> (fsub (fneg B), A) 361 return isNegatibleForFree(Op.getOperand(1), LegalOperations, Depth+1); 362 case ISD::FSUB: 363 // We can't turn -(A-B) into B-A when we honor signed zeros. 364 if (!UnsafeFPMath) return 0; 365 366 // fold (fneg (fsub A, B)) -> (fsub B, A) 367 return 1; 368 369 case ISD::FMUL: 370 case ISD::FDIV: 371 if (HonorSignDependentRoundingFPMath()) return 0; 372 373 // fold (fneg (fmul X, Y)) -> (fmul (fneg X), Y) or (fmul X, (fneg Y)) 374 if (char V = isNegatibleForFree(Op.getOperand(0), LegalOperations, Depth+1)) 375 return V; 376 377 return isNegatibleForFree(Op.getOperand(1), LegalOperations, Depth+1); 378 379 case ISD::FP_EXTEND: 380 case ISD::FP_ROUND: 381 case ISD::FSIN: 382 return isNegatibleForFree(Op.getOperand(0), LegalOperations, Depth+1); 383 } 384} 385 386/// GetNegatedExpression - If isNegatibleForFree returns true, this function 387/// returns the newly negated expression. 388static SDValue GetNegatedExpression(SDValue Op, SelectionDAG &DAG, 389 bool LegalOperations, unsigned Depth = 0) { 390 // fneg is removable even if it has multiple uses. 391 if (Op.getOpcode() == ISD::FNEG) return Op.getOperand(0); 392 393 // Don't allow anything with multiple uses. 394 assert(Op.hasOneUse() && "Unknown reuse!"); 395 396 assert(Depth <= 6 && "GetNegatedExpression doesn't match isNegatibleForFree"); 397 switch (Op.getOpcode()) { 398 default: llvm_unreachable("Unknown code"); 399 case ISD::ConstantFP: { 400 APFloat V = cast<ConstantFPSDNode>(Op)->getValueAPF(); 401 V.changeSign(); 402 return DAG.getConstantFP(V, Op.getValueType()); 403 } 404 case ISD::FADD: 405 // FIXME: determine better conditions for this xform. 406 assert(UnsafeFPMath); 407 408 // fold (fneg (fadd A, B)) -> (fsub (fneg A), B) 409 if (isNegatibleForFree(Op.getOperand(0), LegalOperations, Depth+1)) 410 return DAG.getNode(ISD::FSUB, Op.getDebugLoc(), Op.getValueType(), 411 GetNegatedExpression(Op.getOperand(0), DAG, 412 LegalOperations, Depth+1), 413 Op.getOperand(1)); 414 // fold (fneg (fadd A, B)) -> (fsub (fneg B), A) 415 return DAG.getNode(ISD::FSUB, Op.getDebugLoc(), Op.getValueType(), 416 GetNegatedExpression(Op.getOperand(1), DAG, 417 LegalOperations, Depth+1), 418 Op.getOperand(0)); 419 case ISD::FSUB: 420 // We can't turn -(A-B) into B-A when we honor signed zeros. 421 assert(UnsafeFPMath); 422 423 // fold (fneg (fsub 0, B)) -> B 424 if (ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(Op.getOperand(0))) 425 if (N0CFP->getValueAPF().isZero()) 426 return Op.getOperand(1); 427 428 // fold (fneg (fsub A, B)) -> (fsub B, A) 429 return DAG.getNode(ISD::FSUB, Op.getDebugLoc(), Op.getValueType(), 430 Op.getOperand(1), Op.getOperand(0)); 431 432 case ISD::FMUL: 433 case ISD::FDIV: 434 assert(!HonorSignDependentRoundingFPMath()); 435 436 // fold (fneg (fmul X, Y)) -> (fmul (fneg X), Y) 437 if (isNegatibleForFree(Op.getOperand(0), LegalOperations, Depth+1)) 438 return DAG.getNode(Op.getOpcode(), Op.getDebugLoc(), Op.getValueType(), 439 GetNegatedExpression(Op.getOperand(0), DAG, 440 LegalOperations, Depth+1), 441 Op.getOperand(1)); 442 443 // fold (fneg (fmul X, Y)) -> (fmul X, (fneg Y)) 444 return DAG.getNode(Op.getOpcode(), Op.getDebugLoc(), Op.getValueType(), 445 Op.getOperand(0), 446 GetNegatedExpression(Op.getOperand(1), DAG, 447 LegalOperations, Depth+1)); 448 449 case ISD::FP_EXTEND: 450 case ISD::FSIN: 451 return DAG.getNode(Op.getOpcode(), Op.getDebugLoc(), Op.getValueType(), 452 GetNegatedExpression(Op.getOperand(0), DAG, 453 LegalOperations, Depth+1)); 454 case ISD::FP_ROUND: 455 return DAG.getNode(ISD::FP_ROUND, Op.getDebugLoc(), Op.getValueType(), 456 GetNegatedExpression(Op.getOperand(0), DAG, 457 LegalOperations, Depth+1), 458 Op.getOperand(1)); 459 } 460} 461 462 463// isSetCCEquivalent - Return true if this node is a setcc, or is a select_cc 464// that selects between the values 1 and 0, making it equivalent to a setcc. 465// Also, set the incoming LHS, RHS, and CC references to the appropriate 466// nodes based on the type of node we are checking. This simplifies life a 467// bit for the callers. 468static bool isSetCCEquivalent(SDValue N, SDValue &LHS, SDValue &RHS, 469 SDValue &CC) { 470 if (N.getOpcode() == ISD::SETCC) { 471 LHS = N.getOperand(0); 472 RHS = N.getOperand(1); 473 CC = N.getOperand(2); 474 return true; 475 } 476 if (N.getOpcode() == ISD::SELECT_CC && 477 N.getOperand(2).getOpcode() == ISD::Constant && 478 N.getOperand(3).getOpcode() == ISD::Constant && 479 cast<ConstantSDNode>(N.getOperand(2))->getAPIntValue() == 1 && 480 cast<ConstantSDNode>(N.getOperand(3))->isNullValue()) { 481 LHS = N.getOperand(0); 482 RHS = N.getOperand(1); 483 CC = N.getOperand(4); 484 return true; 485 } 486 return false; 487} 488 489// isOneUseSetCC - Return true if this is a SetCC-equivalent operation with only 490// one use. If this is true, it allows the users to invert the operation for 491// free when it is profitable to do so. 492static bool isOneUseSetCC(SDValue N) { 493 SDValue N0, N1, N2; 494 if (isSetCCEquivalent(N, N0, N1, N2) && N.getNode()->hasOneUse()) 495 return true; 496 return false; 497} 498 499SDValue DAGCombiner::ReassociateOps(unsigned Opc, DebugLoc DL, 500 SDValue N0, SDValue N1) { 501 EVT VT = N0.getValueType(); 502 if (N0.getOpcode() == Opc && isa<ConstantSDNode>(N0.getOperand(1))) { 503 if (isa<ConstantSDNode>(N1)) { 504 // reassoc. (op (op x, c1), c2) -> (op x, (op c1, c2)) 505 SDValue OpNode = 506 DAG.FoldConstantArithmetic(Opc, VT, 507 cast<ConstantSDNode>(N0.getOperand(1)), 508 cast<ConstantSDNode>(N1)); 509 return DAG.getNode(Opc, DL, VT, N0.getOperand(0), OpNode); 510 } else if (N0.hasOneUse()) { 511 // reassoc. (op (op x, c1), y) -> (op (op x, y), c1) iff x+c1 has one use 512 SDValue OpNode = DAG.getNode(Opc, N0.getDebugLoc(), VT, 513 N0.getOperand(0), N1); 514 AddToWorkList(OpNode.getNode()); 515 return DAG.getNode(Opc, DL, VT, OpNode, N0.getOperand(1)); 516 } 517 } 518 519 if (N1.getOpcode() == Opc && isa<ConstantSDNode>(N1.getOperand(1))) { 520 if (isa<ConstantSDNode>(N0)) { 521 // reassoc. (op c2, (op x, c1)) -> (op x, (op c1, c2)) 522 SDValue OpNode = 523 DAG.FoldConstantArithmetic(Opc, VT, 524 cast<ConstantSDNode>(N1.getOperand(1)), 525 cast<ConstantSDNode>(N0)); 526 return DAG.getNode(Opc, DL, VT, N1.getOperand(0), OpNode); 527 } else if (N1.hasOneUse()) { 528 // reassoc. (op y, (op x, c1)) -> (op (op x, y), c1) iff x+c1 has one use 529 SDValue OpNode = DAG.getNode(Opc, N0.getDebugLoc(), VT, 530 N1.getOperand(0), N0); 531 AddToWorkList(OpNode.getNode()); 532 return DAG.getNode(Opc, DL, VT, OpNode, N1.getOperand(1)); 533 } 534 } 535 536 return SDValue(); 537} 538 539SDValue DAGCombiner::CombineTo(SDNode *N, const SDValue *To, unsigned NumTo, 540 bool AddTo) { 541 assert(N->getNumValues() == NumTo && "Broken CombineTo call!"); 542 ++NodesCombined; 543 DEBUG(errs() << "\nReplacing.1 "; 544 N->dump(&DAG); 545 errs() << "\nWith: "; 546 To[0].getNode()->dump(&DAG); 547 errs() << " and " << NumTo-1 << " other values\n"; 548 for (unsigned i = 0, e = NumTo; i != e; ++i) 549 assert(N->getValueType(i) == To[i].getValueType() && 550 "Cannot combine value to value of different type!")); 551 WorkListRemover DeadNodes(*this); 552 DAG.ReplaceAllUsesWith(N, To, &DeadNodes); 553 554 if (AddTo) { 555 // Push the new nodes and any users onto the worklist 556 for (unsigned i = 0, e = NumTo; i != e; ++i) { 557 if (To[i].getNode()) { 558 AddToWorkList(To[i].getNode()); 559 AddUsersToWorkList(To[i].getNode()); 560 } 561 } 562 } 563 564 // Finally, if the node is now dead, remove it from the graph. The node 565 // may not be dead if the replacement process recursively simplified to 566 // something else needing this node. 567 if (N->use_empty()) { 568 // Nodes can be reintroduced into the worklist. Make sure we do not 569 // process a node that has been replaced. 570 removeFromWorkList(N); 571 572 // Finally, since the node is now dead, remove it from the graph. 573 DAG.DeleteNode(N); 574 } 575 return SDValue(N, 0); 576} 577 578void 579DAGCombiner::CommitTargetLoweringOpt(const TargetLowering::TargetLoweringOpt & 580 TLO) { 581 // Replace all uses. If any nodes become isomorphic to other nodes and 582 // are deleted, make sure to remove them from our worklist. 583 WorkListRemover DeadNodes(*this); 584 DAG.ReplaceAllUsesOfValueWith(TLO.Old, TLO.New, &DeadNodes); 585 586 // Push the new node and any (possibly new) users onto the worklist. 587 AddToWorkList(TLO.New.getNode()); 588 AddUsersToWorkList(TLO.New.getNode()); 589 590 // Finally, if the node is now dead, remove it from the graph. The node 591 // may not be dead if the replacement process recursively simplified to 592 // something else needing this node. 593 if (TLO.Old.getNode()->use_empty()) { 594 removeFromWorkList(TLO.Old.getNode()); 595 596 // If the operands of this node are only used by the node, they will now 597 // be dead. Make sure to visit them first to delete dead nodes early. 598 for (unsigned i = 0, e = TLO.Old.getNode()->getNumOperands(); i != e; ++i) 599 if (TLO.Old.getNode()->getOperand(i).getNode()->hasOneUse()) 600 AddToWorkList(TLO.Old.getNode()->getOperand(i).getNode()); 601 602 DAG.DeleteNode(TLO.Old.getNode()); 603 } 604} 605 606/// SimplifyDemandedBits - Check the specified integer node value to see if 607/// it can be simplified or if things it uses can be simplified by bit 608/// propagation. If so, return true. 609bool DAGCombiner::SimplifyDemandedBits(SDValue Op, const APInt &Demanded) { 610 TargetLowering::TargetLoweringOpt TLO(DAG); 611 APInt KnownZero, KnownOne; 612 if (!TLI.SimplifyDemandedBits(Op, Demanded, KnownZero, KnownOne, TLO)) 613 return false; 614 615 // Revisit the node. 616 AddToWorkList(Op.getNode()); 617 618 // Replace the old value with the new one. 619 ++NodesCombined; 620 DEBUG(errs() << "\nReplacing.2 "; 621 TLO.Old.getNode()->dump(&DAG); 622 errs() << "\nWith: "; 623 TLO.New.getNode()->dump(&DAG); 624 errs() << '\n'); 625 626 CommitTargetLoweringOpt(TLO); 627 return true; 628} 629 630//===----------------------------------------------------------------------===// 631// Main DAG Combiner implementation 632//===----------------------------------------------------------------------===// 633 634void DAGCombiner::Run(CombineLevel AtLevel) { 635 // set the instance variables, so that the various visit routines may use it. 636 Level = AtLevel; 637 LegalOperations = Level >= NoIllegalOperations; 638 LegalTypes = Level >= NoIllegalTypes; 639 640 // Add all the dag nodes to the worklist. 641 WorkList.reserve(DAG.allnodes_size()); 642 for (SelectionDAG::allnodes_iterator I = DAG.allnodes_begin(), 643 E = DAG.allnodes_end(); I != E; ++I) 644 WorkList.push_back(I); 645 646 // Create a dummy node (which is not added to allnodes), that adds a reference 647 // to the root node, preventing it from being deleted, and tracking any 648 // changes of the root. 649 HandleSDNode Dummy(DAG.getRoot()); 650 651 // The root of the dag may dangle to deleted nodes until the dag combiner is 652 // done. Set it to null to avoid confusion. 653 DAG.setRoot(SDValue()); 654 655 // while the worklist isn't empty, inspect the node on the end of it and 656 // try and combine it. 657 while (!WorkList.empty()) { 658 SDNode *N = WorkList.back(); 659 WorkList.pop_back(); 660 661 // If N has no uses, it is dead. Make sure to revisit all N's operands once 662 // N is deleted from the DAG, since they too may now be dead or may have a 663 // reduced number of uses, allowing other xforms. 664 if (N->use_empty() && N != &Dummy) { 665 for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) 666 AddToWorkList(N->getOperand(i).getNode()); 667 668 DAG.DeleteNode(N); 669 continue; 670 } 671 672 SDValue RV = combine(N); 673 674 if (RV.getNode() == 0) 675 continue; 676 677 ++NodesCombined; 678 679 // If we get back the same node we passed in, rather than a new node or 680 // zero, we know that the node must have defined multiple values and 681 // CombineTo was used. Since CombineTo takes care of the worklist 682 // mechanics for us, we have no work to do in this case. 683 if (RV.getNode() == N) 684 continue; 685 686 assert(N->getOpcode() != ISD::DELETED_NODE && 687 RV.getNode()->getOpcode() != ISD::DELETED_NODE && 688 "Node was deleted but visit returned new node!"); 689 690 DEBUG(errs() << "\nReplacing.3 "; 691 N->dump(&DAG); 692 errs() << "\nWith: "; 693 RV.getNode()->dump(&DAG); 694 errs() << '\n'); 695 WorkListRemover DeadNodes(*this); 696 if (N->getNumValues() == RV.getNode()->getNumValues()) 697 DAG.ReplaceAllUsesWith(N, RV.getNode(), &DeadNodes); 698 else { 699 assert(N->getValueType(0) == RV.getValueType() && 700 N->getNumValues() == 1 && "Type mismatch"); 701 SDValue OpV = RV; 702 DAG.ReplaceAllUsesWith(N, &OpV, &DeadNodes); 703 } 704 705 // Push the new node and any users onto the worklist 706 AddToWorkList(RV.getNode()); 707 AddUsersToWorkList(RV.getNode()); 708 709 // Add any uses of the old node to the worklist in case this node is the 710 // last one that uses them. They may become dead after this node is 711 // deleted. 712 for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) 713 AddToWorkList(N->getOperand(i).getNode()); 714 715 // Finally, if the node is now dead, remove it from the graph. The node 716 // may not be dead if the replacement process recursively simplified to 717 // something else needing this node. 718 if (N->use_empty()) { 719 // Nodes can be reintroduced into the worklist. Make sure we do not 720 // process a node that has been replaced. 721 removeFromWorkList(N); 722 723 // Finally, since the node is now dead, remove it from the graph. 724 DAG.DeleteNode(N); 725 } 726 } 727 728 // If the root changed (e.g. it was a dead load, update the root). 729 DAG.setRoot(Dummy.getValue()); 730} 731 732SDValue DAGCombiner::visit(SDNode *N) { 733 switch(N->getOpcode()) { 734 default: break; 735 case ISD::TokenFactor: return visitTokenFactor(N); 736 case ISD::MERGE_VALUES: return visitMERGE_VALUES(N); 737 case ISD::ADD: return visitADD(N); 738 case ISD::SUB: return visitSUB(N); 739 case ISD::ADDC: return visitADDC(N); 740 case ISD::ADDE: return visitADDE(N); 741 case ISD::MUL: return visitMUL(N); 742 case ISD::SDIV: return visitSDIV(N); 743 case ISD::UDIV: return visitUDIV(N); 744 case ISD::SREM: return visitSREM(N); 745 case ISD::UREM: return visitUREM(N); 746 case ISD::MULHU: return visitMULHU(N); 747 case ISD::MULHS: return visitMULHS(N); 748 case ISD::SMUL_LOHI: return visitSMUL_LOHI(N); 749 case ISD::UMUL_LOHI: return visitUMUL_LOHI(N); 750 case ISD::SDIVREM: return visitSDIVREM(N); 751 case ISD::UDIVREM: return visitUDIVREM(N); 752 case ISD::AND: return visitAND(N); 753 case ISD::OR: return visitOR(N); 754 case ISD::XOR: return visitXOR(N); 755 case ISD::SHL: return visitSHL(N); 756 case ISD::SRA: return visitSRA(N); 757 case ISD::SRL: return visitSRL(N); 758 case ISD::CTLZ: return visitCTLZ(N); 759 case ISD::CTTZ: return visitCTTZ(N); 760 case ISD::CTPOP: return visitCTPOP(N); 761 case ISD::SELECT: return visitSELECT(N); 762 case ISD::SELECT_CC: return visitSELECT_CC(N); 763 case ISD::SETCC: return visitSETCC(N); 764 case ISD::SIGN_EXTEND: return visitSIGN_EXTEND(N); 765 case ISD::ZERO_EXTEND: return visitZERO_EXTEND(N); 766 case ISD::ANY_EXTEND: return visitANY_EXTEND(N); 767 case ISD::SIGN_EXTEND_INREG: return visitSIGN_EXTEND_INREG(N); 768 case ISD::TRUNCATE: return visitTRUNCATE(N); 769 case ISD::BIT_CONVERT: return visitBIT_CONVERT(N); 770 case ISD::BUILD_PAIR: return visitBUILD_PAIR(N); 771 case ISD::FADD: return visitFADD(N); 772 case ISD::FSUB: return visitFSUB(N); 773 case ISD::FMUL: return visitFMUL(N); 774 case ISD::FDIV: return visitFDIV(N); 775 case ISD::FREM: return visitFREM(N); 776 case ISD::FCOPYSIGN: return visitFCOPYSIGN(N); 777 case ISD::SINT_TO_FP: return visitSINT_TO_FP(N); 778 case ISD::UINT_TO_FP: return visitUINT_TO_FP(N); 779 case ISD::FP_TO_SINT: return visitFP_TO_SINT(N); 780 case ISD::FP_TO_UINT: return visitFP_TO_UINT(N); 781 case ISD::FP_ROUND: return visitFP_ROUND(N); 782 case ISD::FP_ROUND_INREG: return visitFP_ROUND_INREG(N); 783 case ISD::FP_EXTEND: return visitFP_EXTEND(N); 784 case ISD::FNEG: return visitFNEG(N); 785 case ISD::FABS: return visitFABS(N); 786 case ISD::BRCOND: return visitBRCOND(N); 787 case ISD::BR_CC: return visitBR_CC(N); 788 case ISD::LOAD: return visitLOAD(N); 789 case ISD::STORE: return visitSTORE(N); 790 case ISD::INSERT_VECTOR_ELT: return visitINSERT_VECTOR_ELT(N); 791 case ISD::EXTRACT_VECTOR_ELT: return visitEXTRACT_VECTOR_ELT(N); 792 case ISD::BUILD_VECTOR: return visitBUILD_VECTOR(N); 793 case ISD::CONCAT_VECTORS: return visitCONCAT_VECTORS(N); 794 case ISD::VECTOR_SHUFFLE: return visitVECTOR_SHUFFLE(N); 795 } 796 return SDValue(); 797} 798 799SDValue DAGCombiner::combine(SDNode *N) { 800 SDValue RV = visit(N); 801 802 // If nothing happened, try a target-specific DAG combine. 803 if (RV.getNode() == 0) { 804 assert(N->getOpcode() != ISD::DELETED_NODE && 805 "Node was deleted but visit returned NULL!"); 806 807 if (N->getOpcode() >= ISD::BUILTIN_OP_END || 808 TLI.hasTargetDAGCombine((ISD::NodeType)N->getOpcode())) { 809 810 // Expose the DAG combiner to the target combiner impls. 811 TargetLowering::DAGCombinerInfo 812 DagCombineInfo(DAG, !LegalTypes, !LegalOperations, false, this); 813 814 RV = TLI.PerformDAGCombine(N, DagCombineInfo); 815 } 816 } 817 818 // If N is a commutative binary node, try commuting it to enable more 819 // sdisel CSE. 820 if (RV.getNode() == 0 && 821 SelectionDAG::isCommutativeBinOp(N->getOpcode()) && 822 N->getNumValues() == 1) { 823 SDValue N0 = N->getOperand(0); 824 SDValue N1 = N->getOperand(1); 825 826 // Constant operands are canonicalized to RHS. 827 if (isa<ConstantSDNode>(N0) || !isa<ConstantSDNode>(N1)) { 828 SDValue Ops[] = { N1, N0 }; 829 SDNode *CSENode = DAG.getNodeIfExists(N->getOpcode(), N->getVTList(), 830 Ops, 2); 831 if (CSENode) 832 return SDValue(CSENode, 0); 833 } 834 } 835 836 return RV; 837} 838 839/// getInputChainForNode - Given a node, return its input chain if it has one, 840/// otherwise return a null sd operand. 841static SDValue getInputChainForNode(SDNode *N) { 842 if (unsigned NumOps = N->getNumOperands()) { 843 if (N->getOperand(0).getValueType() == MVT::Other) 844 return N->getOperand(0); 845 else if (N->getOperand(NumOps-1).getValueType() == MVT::Other) 846 return N->getOperand(NumOps-1); 847 for (unsigned i = 1; i < NumOps-1; ++i) 848 if (N->getOperand(i).getValueType() == MVT::Other) 849 return N->getOperand(i); 850 } 851 return SDValue(); 852} 853 854SDValue DAGCombiner::visitTokenFactor(SDNode *N) { 855 // If N has two operands, where one has an input chain equal to the other, 856 // the 'other' chain is redundant. 857 if (N->getNumOperands() == 2) { 858 if (getInputChainForNode(N->getOperand(0).getNode()) == N->getOperand(1)) 859 return N->getOperand(0); 860 if (getInputChainForNode(N->getOperand(1).getNode()) == N->getOperand(0)) 861 return N->getOperand(1); 862 } 863 864 SmallVector<SDNode *, 8> TFs; // List of token factors to visit. 865 SmallVector<SDValue, 8> Ops; // Ops for replacing token factor. 866 SmallPtrSet<SDNode*, 16> SeenOps; 867 bool Changed = false; // If we should replace this token factor. 868 869 // Start out with this token factor. 870 TFs.push_back(N); 871 872 // Iterate through token factors. The TFs grows when new token factors are 873 // encountered. 874 for (unsigned i = 0; i < TFs.size(); ++i) { 875 SDNode *TF = TFs[i]; 876 877 // Check each of the operands. 878 for (unsigned i = 0, ie = TF->getNumOperands(); i != ie; ++i) { 879 SDValue Op = TF->getOperand(i); 880 881 switch (Op.getOpcode()) { 882 case ISD::EntryToken: 883 // Entry tokens don't need to be added to the list. They are 884 // rededundant. 885 Changed = true; 886 break; 887 888 case ISD::TokenFactor: 889 if (Op.hasOneUse() && 890 std::find(TFs.begin(), TFs.end(), Op.getNode()) == TFs.end()) { 891 // Queue up for processing. 892 TFs.push_back(Op.getNode()); 893 // Clean up in case the token factor is removed. 894 AddToWorkList(Op.getNode()); 895 Changed = true; 896 break; 897 } 898 // Fall thru 899 900 default: 901 // Only add if it isn't already in the list. 902 if (SeenOps.insert(Op.getNode())) 903 Ops.push_back(Op); 904 else 905 Changed = true; 906 break; 907 } 908 } 909 } 910 911 SDValue Result; 912 913 // If we've change things around then replace token factor. 914 if (Changed) { 915 if (Ops.empty()) { 916 // The entry token is the only possible outcome. 917 Result = DAG.getEntryNode(); 918 } else { 919 // New and improved token factor. 920 Result = DAG.getNode(ISD::TokenFactor, N->getDebugLoc(), 921 MVT::Other, &Ops[0], Ops.size()); 922 } 923 924 // Don't add users to work list. 925 return CombineTo(N, Result, false); 926 } 927 928 return Result; 929} 930 931/// MERGE_VALUES can always be eliminated. 932SDValue DAGCombiner::visitMERGE_VALUES(SDNode *N) { 933 WorkListRemover DeadNodes(*this); 934 // Replacing results may cause a different MERGE_VALUES to suddenly 935 // be CSE'd with N, and carry its uses with it. Iterate until no 936 // uses remain, to ensure that the node can be safely deleted. 937 do { 938 for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) 939 DAG.ReplaceAllUsesOfValueWith(SDValue(N, i), N->getOperand(i), 940 &DeadNodes); 941 } while (!N->use_empty()); 942 removeFromWorkList(N); 943 DAG.DeleteNode(N); 944 return SDValue(N, 0); // Return N so it doesn't get rechecked! 945} 946 947static 948SDValue combineShlAddConstant(DebugLoc DL, SDValue N0, SDValue N1, 949 SelectionDAG &DAG) { 950 EVT VT = N0.getValueType(); 951 SDValue N00 = N0.getOperand(0); 952 SDValue N01 = N0.getOperand(1); 953 ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N01); 954 955 if (N01C && N00.getOpcode() == ISD::ADD && N00.getNode()->hasOneUse() && 956 isa<ConstantSDNode>(N00.getOperand(1))) { 957 // fold (add (shl (add x, c1), c2), ) -> (add (add (shl x, c2), c1<<c2), ) 958 N0 = DAG.getNode(ISD::ADD, N0.getDebugLoc(), VT, 959 DAG.getNode(ISD::SHL, N00.getDebugLoc(), VT, 960 N00.getOperand(0), N01), 961 DAG.getNode(ISD::SHL, N01.getDebugLoc(), VT, 962 N00.getOperand(1), N01)); 963 return DAG.getNode(ISD::ADD, DL, VT, N0, N1); 964 } 965 966 return SDValue(); 967} 968 969SDValue DAGCombiner::visitADD(SDNode *N) { 970 SDValue N0 = N->getOperand(0); 971 SDValue N1 = N->getOperand(1); 972 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 973 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 974 EVT VT = N0.getValueType(); 975 976 // fold vector ops 977 if (VT.isVector()) { 978 SDValue FoldedVOp = SimplifyVBinOp(N); 979 if (FoldedVOp.getNode()) return FoldedVOp; 980 } 981 982 // fold (add x, undef) -> undef 983 if (N0.getOpcode() == ISD::UNDEF) 984 return N0; 985 if (N1.getOpcode() == ISD::UNDEF) 986 return N1; 987 // fold (add c1, c2) -> c1+c2 988 if (N0C && N1C) 989 return DAG.FoldConstantArithmetic(ISD::ADD, VT, N0C, N1C); 990 // canonicalize constant to RHS 991 if (N0C && !N1C) 992 return DAG.getNode(ISD::ADD, N->getDebugLoc(), VT, N1, N0); 993 // fold (add x, 0) -> x 994 if (N1C && N1C->isNullValue()) 995 return N0; 996 // fold (add Sym, c) -> Sym+c 997 if (GlobalAddressSDNode *GA = dyn_cast<GlobalAddressSDNode>(N0)) 998 if (!LegalOperations && TLI.isOffsetFoldingLegal(GA) && N1C && 999 GA->getOpcode() == ISD::GlobalAddress) 1000 return DAG.getGlobalAddress(GA->getGlobal(), VT, 1001 GA->getOffset() + 1002 (uint64_t)N1C->getSExtValue()); 1003 // fold ((c1-A)+c2) -> (c1+c2)-A 1004 if (N1C && N0.getOpcode() == ISD::SUB) 1005 if (ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.getOperand(0))) 1006 return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, 1007 DAG.getConstant(N1C->getAPIntValue()+ 1008 N0C->getAPIntValue(), VT), 1009 N0.getOperand(1)); 1010 // reassociate add 1011 SDValue RADD = ReassociateOps(ISD::ADD, N->getDebugLoc(), N0, N1); 1012 if (RADD.getNode() != 0) 1013 return RADD; 1014 // fold ((0-A) + B) -> B-A 1015 if (N0.getOpcode() == ISD::SUB && isa<ConstantSDNode>(N0.getOperand(0)) && 1016 cast<ConstantSDNode>(N0.getOperand(0))->isNullValue()) 1017 return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N1, N0.getOperand(1)); 1018 // fold (A + (0-B)) -> A-B 1019 if (N1.getOpcode() == ISD::SUB && isa<ConstantSDNode>(N1.getOperand(0)) && 1020 cast<ConstantSDNode>(N1.getOperand(0))->isNullValue()) 1021 return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N0, N1.getOperand(1)); 1022 // fold (A+(B-A)) -> B 1023 if (N1.getOpcode() == ISD::SUB && N0 == N1.getOperand(1)) 1024 return N1.getOperand(0); 1025 // fold ((B-A)+A) -> B 1026 if (N0.getOpcode() == ISD::SUB && N1 == N0.getOperand(1)) 1027 return N0.getOperand(0); 1028 // fold (A+(B-(A+C))) to (B-C) 1029 if (N1.getOpcode() == ISD::SUB && N1.getOperand(1).getOpcode() == ISD::ADD && 1030 N0 == N1.getOperand(1).getOperand(0)) 1031 return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N1.getOperand(0), 1032 N1.getOperand(1).getOperand(1)); 1033 // fold (A+(B-(C+A))) to (B-C) 1034 if (N1.getOpcode() == ISD::SUB && N1.getOperand(1).getOpcode() == ISD::ADD && 1035 N0 == N1.getOperand(1).getOperand(1)) 1036 return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N1.getOperand(0), 1037 N1.getOperand(1).getOperand(0)); 1038 // fold (A+((B-A)+or-C)) to (B+or-C) 1039 if ((N1.getOpcode() == ISD::SUB || N1.getOpcode() == ISD::ADD) && 1040 N1.getOperand(0).getOpcode() == ISD::SUB && 1041 N0 == N1.getOperand(0).getOperand(1)) 1042 return DAG.getNode(N1.getOpcode(), N->getDebugLoc(), VT, 1043 N1.getOperand(0).getOperand(0), N1.getOperand(1)); 1044 1045 // fold (A-B)+(C-D) to (A+C)-(B+D) when A or C is constant 1046 if (N0.getOpcode() == ISD::SUB && N1.getOpcode() == ISD::SUB) { 1047 SDValue N00 = N0.getOperand(0); 1048 SDValue N01 = N0.getOperand(1); 1049 SDValue N10 = N1.getOperand(0); 1050 SDValue N11 = N1.getOperand(1); 1051 1052 if (isa<ConstantSDNode>(N00) || isa<ConstantSDNode>(N10)) 1053 return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, 1054 DAG.getNode(ISD::ADD, N0.getDebugLoc(), VT, N00, N10), 1055 DAG.getNode(ISD::ADD, N1.getDebugLoc(), VT, N01, N11)); 1056 } 1057 1058 if (!VT.isVector() && SimplifyDemandedBits(SDValue(N, 0))) 1059 return SDValue(N, 0); 1060 1061 // fold (a+b) -> (a|b) iff a and b share no bits. 1062 if (VT.isInteger() && !VT.isVector()) { 1063 APInt LHSZero, LHSOne; 1064 APInt RHSZero, RHSOne; 1065 APInt Mask = APInt::getAllOnesValue(VT.getSizeInBits()); 1066 DAG.ComputeMaskedBits(N0, Mask, LHSZero, LHSOne); 1067 1068 if (LHSZero.getBoolValue()) { 1069 DAG.ComputeMaskedBits(N1, Mask, RHSZero, RHSOne); 1070 1071 // If all possibly-set bits on the LHS are clear on the RHS, return an OR. 1072 // If all possibly-set bits on the RHS are clear on the LHS, return an OR. 1073 if ((RHSZero & (~LHSZero & Mask)) == (~LHSZero & Mask) || 1074 (LHSZero & (~RHSZero & Mask)) == (~RHSZero & Mask)) 1075 return DAG.getNode(ISD::OR, N->getDebugLoc(), VT, N0, N1); 1076 } 1077 } 1078 1079 // fold (add (shl (add x, c1), c2), ) -> (add (add (shl x, c2), c1<<c2), ) 1080 if (N0.getOpcode() == ISD::SHL && N0.getNode()->hasOneUse()) { 1081 SDValue Result = combineShlAddConstant(N->getDebugLoc(), N0, N1, DAG); 1082 if (Result.getNode()) return Result; 1083 } 1084 if (N1.getOpcode() == ISD::SHL && N1.getNode()->hasOneUse()) { 1085 SDValue Result = combineShlAddConstant(N->getDebugLoc(), N1, N0, DAG); 1086 if (Result.getNode()) return Result; 1087 } 1088 1089 return SDValue(); 1090} 1091 1092SDValue DAGCombiner::visitADDC(SDNode *N) { 1093 SDValue N0 = N->getOperand(0); 1094 SDValue N1 = N->getOperand(1); 1095 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 1096 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1097 EVT VT = N0.getValueType(); 1098 1099 // If the flag result is dead, turn this into an ADD. 1100 if (N->hasNUsesOfValue(0, 1)) 1101 return CombineTo(N, DAG.getNode(ISD::ADD, N->getDebugLoc(), VT, N1, N0), 1102 DAG.getNode(ISD::CARRY_FALSE, 1103 N->getDebugLoc(), MVT::Flag)); 1104 1105 // canonicalize constant to RHS. 1106 if (N0C && !N1C) 1107 return DAG.getNode(ISD::ADDC, N->getDebugLoc(), N->getVTList(), N1, N0); 1108 1109 // fold (addc x, 0) -> x + no carry out 1110 if (N1C && N1C->isNullValue()) 1111 return CombineTo(N, N0, DAG.getNode(ISD::CARRY_FALSE, 1112 N->getDebugLoc(), MVT::Flag)); 1113 1114 // fold (addc a, b) -> (or a, b), CARRY_FALSE iff a and b share no bits. 1115 APInt LHSZero, LHSOne; 1116 APInt RHSZero, RHSOne; 1117 APInt Mask = APInt::getAllOnesValue(VT.getSizeInBits()); 1118 DAG.ComputeMaskedBits(N0, Mask, LHSZero, LHSOne); 1119 1120 if (LHSZero.getBoolValue()) { 1121 DAG.ComputeMaskedBits(N1, Mask, RHSZero, RHSOne); 1122 1123 // If all possibly-set bits on the LHS are clear on the RHS, return an OR. 1124 // If all possibly-set bits on the RHS are clear on the LHS, return an OR. 1125 if ((RHSZero & (~LHSZero & Mask)) == (~LHSZero & Mask) || 1126 (LHSZero & (~RHSZero & Mask)) == (~RHSZero & Mask)) 1127 return CombineTo(N, DAG.getNode(ISD::OR, N->getDebugLoc(), VT, N0, N1), 1128 DAG.getNode(ISD::CARRY_FALSE, 1129 N->getDebugLoc(), MVT::Flag)); 1130 } 1131 1132 return SDValue(); 1133} 1134 1135SDValue DAGCombiner::visitADDE(SDNode *N) { 1136 SDValue N0 = N->getOperand(0); 1137 SDValue N1 = N->getOperand(1); 1138 SDValue CarryIn = N->getOperand(2); 1139 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 1140 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1141 1142 // canonicalize constant to RHS 1143 if (N0C && !N1C) 1144 return DAG.getNode(ISD::ADDE, N->getDebugLoc(), N->getVTList(), 1145 N1, N0, CarryIn); 1146 1147 // fold (adde x, y, false) -> (addc x, y) 1148 if (CarryIn.getOpcode() == ISD::CARRY_FALSE) 1149 return DAG.getNode(ISD::ADDC, N->getDebugLoc(), N->getVTList(), N1, N0); 1150 1151 return SDValue(); 1152} 1153 1154SDValue DAGCombiner::visitSUB(SDNode *N) { 1155 SDValue N0 = N->getOperand(0); 1156 SDValue N1 = N->getOperand(1); 1157 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.getNode()); 1158 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.getNode()); 1159 EVT VT = N0.getValueType(); 1160 1161 // fold vector ops 1162 if (VT.isVector()) { 1163 SDValue FoldedVOp = SimplifyVBinOp(N); 1164 if (FoldedVOp.getNode()) return FoldedVOp; 1165 } 1166 1167 // fold (sub x, x) -> 0 1168 if (N0 == N1) 1169 return DAG.getConstant(0, N->getValueType(0)); 1170 // fold (sub c1, c2) -> c1-c2 1171 if (N0C && N1C) 1172 return DAG.FoldConstantArithmetic(ISD::SUB, VT, N0C, N1C); 1173 // fold (sub x, c) -> (add x, -c) 1174 if (N1C) 1175 return DAG.getNode(ISD::ADD, N->getDebugLoc(), VT, N0, 1176 DAG.getConstant(-N1C->getAPIntValue(), VT)); 1177 // fold (A+B)-A -> B 1178 if (N0.getOpcode() == ISD::ADD && N0.getOperand(0) == N1) 1179 return N0.getOperand(1); 1180 // fold (A+B)-B -> A 1181 if (N0.getOpcode() == ISD::ADD && N0.getOperand(1) == N1) 1182 return N0.getOperand(0); 1183 // fold ((A+(B+or-C))-B) -> A+or-C 1184 if (N0.getOpcode() == ISD::ADD && 1185 (N0.getOperand(1).getOpcode() == ISD::SUB || 1186 N0.getOperand(1).getOpcode() == ISD::ADD) && 1187 N0.getOperand(1).getOperand(0) == N1) 1188 return DAG.getNode(N0.getOperand(1).getOpcode(), N->getDebugLoc(), VT, 1189 N0.getOperand(0), N0.getOperand(1).getOperand(1)); 1190 // fold ((A+(C+B))-B) -> A+C 1191 if (N0.getOpcode() == ISD::ADD && 1192 N0.getOperand(1).getOpcode() == ISD::ADD && 1193 N0.getOperand(1).getOperand(1) == N1) 1194 return DAG.getNode(ISD::ADD, N->getDebugLoc(), VT, 1195 N0.getOperand(0), N0.getOperand(1).getOperand(0)); 1196 // fold ((A-(B-C))-C) -> A-B 1197 if (N0.getOpcode() == ISD::SUB && 1198 N0.getOperand(1).getOpcode() == ISD::SUB && 1199 N0.getOperand(1).getOperand(1) == N1) 1200 return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, 1201 N0.getOperand(0), N0.getOperand(1).getOperand(0)); 1202 1203 // If either operand of a sub is undef, the result is undef 1204 if (N0.getOpcode() == ISD::UNDEF) 1205 return N0; 1206 if (N1.getOpcode() == ISD::UNDEF) 1207 return N1; 1208 1209 // If the relocation model supports it, consider symbol offsets. 1210 if (GlobalAddressSDNode *GA = dyn_cast<GlobalAddressSDNode>(N0)) 1211 if (!LegalOperations && TLI.isOffsetFoldingLegal(GA)) { 1212 // fold (sub Sym, c) -> Sym-c 1213 if (N1C && GA->getOpcode() == ISD::GlobalAddress) 1214 return DAG.getGlobalAddress(GA->getGlobal(), VT, 1215 GA->getOffset() - 1216 (uint64_t)N1C->getSExtValue()); 1217 // fold (sub Sym+c1, Sym+c2) -> c1-c2 1218 if (GlobalAddressSDNode *GB = dyn_cast<GlobalAddressSDNode>(N1)) 1219 if (GA->getGlobal() == GB->getGlobal()) 1220 return DAG.getConstant((uint64_t)GA->getOffset() - GB->getOffset(), 1221 VT); 1222 } 1223 1224 return SDValue(); 1225} 1226 1227SDValue DAGCombiner::visitMUL(SDNode *N) { 1228 SDValue N0 = N->getOperand(0); 1229 SDValue N1 = N->getOperand(1); 1230 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 1231 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1232 EVT VT = N0.getValueType(); 1233 1234 // fold vector ops 1235 if (VT.isVector()) { 1236 SDValue FoldedVOp = SimplifyVBinOp(N); 1237 if (FoldedVOp.getNode()) return FoldedVOp; 1238 } 1239 1240 // fold (mul x, undef) -> 0 1241 if (N0.getOpcode() == ISD::UNDEF || N1.getOpcode() == ISD::UNDEF) 1242 return DAG.getConstant(0, VT); 1243 // fold (mul c1, c2) -> c1*c2 1244 if (N0C && N1C) 1245 return DAG.FoldConstantArithmetic(ISD::MUL, VT, N0C, N1C); 1246 // canonicalize constant to RHS 1247 if (N0C && !N1C) 1248 return DAG.getNode(ISD::MUL, N->getDebugLoc(), VT, N1, N0); 1249 // fold (mul x, 0) -> 0 1250 if (N1C && N1C->isNullValue()) 1251 return N1; 1252 // fold (mul x, -1) -> 0-x 1253 if (N1C && N1C->isAllOnesValue()) 1254 return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, 1255 DAG.getConstant(0, VT), N0); 1256 // fold (mul x, (1 << c)) -> x << c 1257 if (N1C && N1C->getAPIntValue().isPowerOf2()) 1258 return DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, N0, 1259 DAG.getConstant(N1C->getAPIntValue().logBase2(), 1260 getShiftAmountTy())); 1261 // fold (mul x, -(1 << c)) -> -(x << c) or (-x) << c 1262 if (N1C && (-N1C->getAPIntValue()).isPowerOf2()) { 1263 unsigned Log2Val = (-N1C->getAPIntValue()).logBase2(); 1264 // FIXME: If the input is something that is easily negated (e.g. a 1265 // single-use add), we should put the negate there. 1266 return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, 1267 DAG.getConstant(0, VT), 1268 DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, N0, 1269 DAG.getConstant(Log2Val, getShiftAmountTy()))); 1270 } 1271 // (mul (shl X, c1), c2) -> (mul X, c2 << c1) 1272 if (N1C && N0.getOpcode() == ISD::SHL && 1273 isa<ConstantSDNode>(N0.getOperand(1))) { 1274 SDValue C3 = DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, 1275 N1, N0.getOperand(1)); 1276 AddToWorkList(C3.getNode()); 1277 return DAG.getNode(ISD::MUL, N->getDebugLoc(), VT, 1278 N0.getOperand(0), C3); 1279 } 1280 1281 // Change (mul (shl X, C), Y) -> (shl (mul X, Y), C) when the shift has one 1282 // use. 1283 { 1284 SDValue Sh(0,0), Y(0,0); 1285 // Check for both (mul (shl X, C), Y) and (mul Y, (shl X, C)). 1286 if (N0.getOpcode() == ISD::SHL && isa<ConstantSDNode>(N0.getOperand(1)) && 1287 N0.getNode()->hasOneUse()) { 1288 Sh = N0; Y = N1; 1289 } else if (N1.getOpcode() == ISD::SHL && 1290 isa<ConstantSDNode>(N1.getOperand(1)) && 1291 N1.getNode()->hasOneUse()) { 1292 Sh = N1; Y = N0; 1293 } 1294 1295 if (Sh.getNode()) { 1296 SDValue Mul = DAG.getNode(ISD::MUL, N->getDebugLoc(), VT, 1297 Sh.getOperand(0), Y); 1298 return DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, 1299 Mul, Sh.getOperand(1)); 1300 } 1301 } 1302 1303 // fold (mul (add x, c1), c2) -> (add (mul x, c2), c1*c2) 1304 if (N1C && N0.getOpcode() == ISD::ADD && N0.getNode()->hasOneUse() && 1305 isa<ConstantSDNode>(N0.getOperand(1))) 1306 return DAG.getNode(ISD::ADD, N->getDebugLoc(), VT, 1307 DAG.getNode(ISD::MUL, N0.getDebugLoc(), VT, 1308 N0.getOperand(0), N1), 1309 DAG.getNode(ISD::MUL, N1.getDebugLoc(), VT, 1310 N0.getOperand(1), N1)); 1311 1312 // reassociate mul 1313 SDValue RMUL = ReassociateOps(ISD::MUL, N->getDebugLoc(), N0, N1); 1314 if (RMUL.getNode() != 0) 1315 return RMUL; 1316 1317 return SDValue(); 1318} 1319 1320SDValue DAGCombiner::visitSDIV(SDNode *N) { 1321 SDValue N0 = N->getOperand(0); 1322 SDValue N1 = N->getOperand(1); 1323 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.getNode()); 1324 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.getNode()); 1325 EVT VT = N->getValueType(0); 1326 1327 // fold vector ops 1328 if (VT.isVector()) { 1329 SDValue FoldedVOp = SimplifyVBinOp(N); 1330 if (FoldedVOp.getNode()) return FoldedVOp; 1331 } 1332 1333 // fold (sdiv c1, c2) -> c1/c2 1334 if (N0C && N1C && !N1C->isNullValue()) 1335 return DAG.FoldConstantArithmetic(ISD::SDIV, VT, N0C, N1C); 1336 // fold (sdiv X, 1) -> X 1337 if (N1C && N1C->getSExtValue() == 1LL) 1338 return N0; 1339 // fold (sdiv X, -1) -> 0-X 1340 if (N1C && N1C->isAllOnesValue()) 1341 return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, 1342 DAG.getConstant(0, VT), N0); 1343 // If we know the sign bits of both operands are zero, strength reduce to a 1344 // udiv instead. Handles (X&15) /s 4 -> X&15 >> 2 1345 if (!VT.isVector()) { 1346 if (DAG.SignBitIsZero(N1) && DAG.SignBitIsZero(N0)) 1347 return DAG.getNode(ISD::UDIV, N->getDebugLoc(), N1.getValueType(), 1348 N0, N1); 1349 } 1350 // fold (sdiv X, pow2) -> simple ops after legalize 1351 if (N1C && !N1C->isNullValue() && !TLI.isIntDivCheap() && 1352 (isPowerOf2_64(N1C->getSExtValue()) || 1353 isPowerOf2_64(-N1C->getSExtValue()))) { 1354 // If dividing by powers of two is cheap, then don't perform the following 1355 // fold. 1356 if (TLI.isPow2DivCheap()) 1357 return SDValue(); 1358 1359 int64_t pow2 = N1C->getSExtValue(); 1360 int64_t abs2 = pow2 > 0 ? pow2 : -pow2; 1361 unsigned lg2 = Log2_64(abs2); 1362 1363 // Splat the sign bit into the register 1364 SDValue SGN = DAG.getNode(ISD::SRA, N->getDebugLoc(), VT, N0, 1365 DAG.getConstant(VT.getSizeInBits()-1, 1366 getShiftAmountTy())); 1367 AddToWorkList(SGN.getNode()); 1368 1369 // Add (N0 < 0) ? abs2 - 1 : 0; 1370 SDValue SRL = DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, SGN, 1371 DAG.getConstant(VT.getSizeInBits() - lg2, 1372 getShiftAmountTy())); 1373 SDValue ADD = DAG.getNode(ISD::ADD, N->getDebugLoc(), VT, N0, SRL); 1374 AddToWorkList(SRL.getNode()); 1375 AddToWorkList(ADD.getNode()); // Divide by pow2 1376 SDValue SRA = DAG.getNode(ISD::SRA, N->getDebugLoc(), VT, ADD, 1377 DAG.getConstant(lg2, getShiftAmountTy())); 1378 1379 // If we're dividing by a positive value, we're done. Otherwise, we must 1380 // negate the result. 1381 if (pow2 > 0) 1382 return SRA; 1383 1384 AddToWorkList(SRA.getNode()); 1385 return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, 1386 DAG.getConstant(0, VT), SRA); 1387 } 1388 1389 // if integer divide is expensive and we satisfy the requirements, emit an 1390 // alternate sequence. 1391 if (N1C && (N1C->getSExtValue() < -1 || N1C->getSExtValue() > 1) && 1392 !TLI.isIntDivCheap()) { 1393 SDValue Op = BuildSDIV(N); 1394 if (Op.getNode()) return Op; 1395 } 1396 1397 // undef / X -> 0 1398 if (N0.getOpcode() == ISD::UNDEF) 1399 return DAG.getConstant(0, VT); 1400 // X / undef -> undef 1401 if (N1.getOpcode() == ISD::UNDEF) 1402 return N1; 1403 1404 return SDValue(); 1405} 1406 1407SDValue DAGCombiner::visitUDIV(SDNode *N) { 1408 SDValue N0 = N->getOperand(0); 1409 SDValue N1 = N->getOperand(1); 1410 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.getNode()); 1411 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.getNode()); 1412 EVT VT = N->getValueType(0); 1413 1414 // fold vector ops 1415 if (VT.isVector()) { 1416 SDValue FoldedVOp = SimplifyVBinOp(N); 1417 if (FoldedVOp.getNode()) return FoldedVOp; 1418 } 1419 1420 // fold (udiv c1, c2) -> c1/c2 1421 if (N0C && N1C && !N1C->isNullValue()) 1422 return DAG.FoldConstantArithmetic(ISD::UDIV, VT, N0C, N1C); 1423 // fold (udiv x, (1 << c)) -> x >>u c 1424 if (N1C && N1C->getAPIntValue().isPowerOf2()) 1425 return DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, N0, 1426 DAG.getConstant(N1C->getAPIntValue().logBase2(), 1427 getShiftAmountTy())); 1428 // fold (udiv x, (shl c, y)) -> x >>u (log2(c)+y) iff c is power of 2 1429 if (N1.getOpcode() == ISD::SHL) { 1430 if (ConstantSDNode *SHC = dyn_cast<ConstantSDNode>(N1.getOperand(0))) { 1431 if (SHC->getAPIntValue().isPowerOf2()) { 1432 EVT ADDVT = N1.getOperand(1).getValueType(); 1433 SDValue Add = DAG.getNode(ISD::ADD, N->getDebugLoc(), ADDVT, 1434 N1.getOperand(1), 1435 DAG.getConstant(SHC->getAPIntValue() 1436 .logBase2(), 1437 ADDVT)); 1438 AddToWorkList(Add.getNode()); 1439 return DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, N0, Add); 1440 } 1441 } 1442 } 1443 // fold (udiv x, c) -> alternate 1444 if (N1C && !N1C->isNullValue() && !TLI.isIntDivCheap()) { 1445 SDValue Op = BuildUDIV(N); 1446 if (Op.getNode()) return Op; 1447 } 1448 1449 // undef / X -> 0 1450 if (N0.getOpcode() == ISD::UNDEF) 1451 return DAG.getConstant(0, VT); 1452 // X / undef -> undef 1453 if (N1.getOpcode() == ISD::UNDEF) 1454 return N1; 1455 1456 return SDValue(); 1457} 1458 1459SDValue DAGCombiner::visitSREM(SDNode *N) { 1460 SDValue N0 = N->getOperand(0); 1461 SDValue N1 = N->getOperand(1); 1462 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 1463 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1464 EVT VT = N->getValueType(0); 1465 1466 // fold (srem c1, c2) -> c1%c2 1467 if (N0C && N1C && !N1C->isNullValue()) 1468 return DAG.FoldConstantArithmetic(ISD::SREM, VT, N0C, N1C); 1469 // If we know the sign bits of both operands are zero, strength reduce to a 1470 // urem instead. Handles (X & 0x0FFFFFFF) %s 16 -> X&15 1471 if (!VT.isVector()) { 1472 if (DAG.SignBitIsZero(N1) && DAG.SignBitIsZero(N0)) 1473 return DAG.getNode(ISD::UREM, N->getDebugLoc(), VT, N0, N1); 1474 } 1475 1476 // If X/C can be simplified by the division-by-constant logic, lower 1477 // X%C to the equivalent of X-X/C*C. 1478 if (N1C && !N1C->isNullValue()) { 1479 SDValue Div = DAG.getNode(ISD::SDIV, N->getDebugLoc(), VT, N0, N1); 1480 AddToWorkList(Div.getNode()); 1481 SDValue OptimizedDiv = combine(Div.getNode()); 1482 if (OptimizedDiv.getNode() && OptimizedDiv.getNode() != Div.getNode()) { 1483 SDValue Mul = DAG.getNode(ISD::MUL, N->getDebugLoc(), VT, 1484 OptimizedDiv, N1); 1485 SDValue Sub = DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N0, Mul); 1486 AddToWorkList(Mul.getNode()); 1487 return Sub; 1488 } 1489 } 1490 1491 // undef % X -> 0 1492 if (N0.getOpcode() == ISD::UNDEF) 1493 return DAG.getConstant(0, VT); 1494 // X % undef -> undef 1495 if (N1.getOpcode() == ISD::UNDEF) 1496 return N1; 1497 1498 return SDValue(); 1499} 1500 1501SDValue DAGCombiner::visitUREM(SDNode *N) { 1502 SDValue N0 = N->getOperand(0); 1503 SDValue N1 = N->getOperand(1); 1504 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 1505 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1506 EVT VT = N->getValueType(0); 1507 1508 // fold (urem c1, c2) -> c1%c2 1509 if (N0C && N1C && !N1C->isNullValue()) 1510 return DAG.FoldConstantArithmetic(ISD::UREM, VT, N0C, N1C); 1511 // fold (urem x, pow2) -> (and x, pow2-1) 1512 if (N1C && !N1C->isNullValue() && N1C->getAPIntValue().isPowerOf2()) 1513 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, N0, 1514 DAG.getConstant(N1C->getAPIntValue()-1,VT)); 1515 // fold (urem x, (shl pow2, y)) -> (and x, (add (shl pow2, y), -1)) 1516 if (N1.getOpcode() == ISD::SHL) { 1517 if (ConstantSDNode *SHC = dyn_cast<ConstantSDNode>(N1.getOperand(0))) { 1518 if (SHC->getAPIntValue().isPowerOf2()) { 1519 SDValue Add = 1520 DAG.getNode(ISD::ADD, N->getDebugLoc(), VT, N1, 1521 DAG.getConstant(APInt::getAllOnesValue(VT.getSizeInBits()), 1522 VT)); 1523 AddToWorkList(Add.getNode()); 1524 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, N0, Add); 1525 } 1526 } 1527 } 1528 1529 // If X/C can be simplified by the division-by-constant logic, lower 1530 // X%C to the equivalent of X-X/C*C. 1531 if (N1C && !N1C->isNullValue()) { 1532 SDValue Div = DAG.getNode(ISD::UDIV, N->getDebugLoc(), VT, N0, N1); 1533 AddToWorkList(Div.getNode()); 1534 SDValue OptimizedDiv = combine(Div.getNode()); 1535 if (OptimizedDiv.getNode() && OptimizedDiv.getNode() != Div.getNode()) { 1536 SDValue Mul = DAG.getNode(ISD::MUL, N->getDebugLoc(), VT, 1537 OptimizedDiv, N1); 1538 SDValue Sub = DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N0, Mul); 1539 AddToWorkList(Mul.getNode()); 1540 return Sub; 1541 } 1542 } 1543 1544 // undef % X -> 0 1545 if (N0.getOpcode() == ISD::UNDEF) 1546 return DAG.getConstant(0, VT); 1547 // X % undef -> undef 1548 if (N1.getOpcode() == ISD::UNDEF) 1549 return N1; 1550 1551 return SDValue(); 1552} 1553 1554SDValue DAGCombiner::visitMULHS(SDNode *N) { 1555 SDValue N0 = N->getOperand(0); 1556 SDValue N1 = N->getOperand(1); 1557 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1558 EVT VT = N->getValueType(0); 1559 1560 // fold (mulhs x, 0) -> 0 1561 if (N1C && N1C->isNullValue()) 1562 return N1; 1563 // fold (mulhs x, 1) -> (sra x, size(x)-1) 1564 if (N1C && N1C->getAPIntValue() == 1) 1565 return DAG.getNode(ISD::SRA, N->getDebugLoc(), N0.getValueType(), N0, 1566 DAG.getConstant(N0.getValueType().getSizeInBits() - 1, 1567 getShiftAmountTy())); 1568 // fold (mulhs x, undef) -> 0 1569 if (N0.getOpcode() == ISD::UNDEF || N1.getOpcode() == ISD::UNDEF) 1570 return DAG.getConstant(0, VT); 1571 1572 return SDValue(); 1573} 1574 1575SDValue DAGCombiner::visitMULHU(SDNode *N) { 1576 SDValue N0 = N->getOperand(0); 1577 SDValue N1 = N->getOperand(1); 1578 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1579 EVT VT = N->getValueType(0); 1580 1581 // fold (mulhu x, 0) -> 0 1582 if (N1C && N1C->isNullValue()) 1583 return N1; 1584 // fold (mulhu x, 1) -> 0 1585 if (N1C && N1C->getAPIntValue() == 1) 1586 return DAG.getConstant(0, N0.getValueType()); 1587 // fold (mulhu x, undef) -> 0 1588 if (N0.getOpcode() == ISD::UNDEF || N1.getOpcode() == ISD::UNDEF) 1589 return DAG.getConstant(0, VT); 1590 1591 return SDValue(); 1592} 1593 1594/// SimplifyNodeWithTwoResults - Perform optimizations common to nodes that 1595/// compute two values. LoOp and HiOp give the opcodes for the two computations 1596/// that are being performed. Return true if a simplification was made. 1597/// 1598SDValue DAGCombiner::SimplifyNodeWithTwoResults(SDNode *N, unsigned LoOp, 1599 unsigned HiOp) { 1600 // If the high half is not needed, just compute the low half. 1601 bool HiExists = N->hasAnyUseOfValue(1); 1602 if (!HiExists && 1603 (!LegalOperations || 1604 TLI.isOperationLegal(LoOp, N->getValueType(0)))) { 1605 SDValue Res = DAG.getNode(LoOp, N->getDebugLoc(), N->getValueType(0), 1606 N->op_begin(), N->getNumOperands()); 1607 return CombineTo(N, Res, Res); 1608 } 1609 1610 // If the low half is not needed, just compute the high half. 1611 bool LoExists = N->hasAnyUseOfValue(0); 1612 if (!LoExists && 1613 (!LegalOperations || 1614 TLI.isOperationLegal(HiOp, N->getValueType(1)))) { 1615 SDValue Res = DAG.getNode(HiOp, N->getDebugLoc(), N->getValueType(1), 1616 N->op_begin(), N->getNumOperands()); 1617 return CombineTo(N, Res, Res); 1618 } 1619 1620 // If both halves are used, return as it is. 1621 if (LoExists && HiExists) 1622 return SDValue(); 1623 1624 // If the two computed results can be simplified separately, separate them. 1625 if (LoExists) { 1626 SDValue Lo = DAG.getNode(LoOp, N->getDebugLoc(), N->getValueType(0), 1627 N->op_begin(), N->getNumOperands()); 1628 AddToWorkList(Lo.getNode()); 1629 SDValue LoOpt = combine(Lo.getNode()); 1630 if (LoOpt.getNode() && LoOpt.getNode() != Lo.getNode() && 1631 (!LegalOperations || 1632 TLI.isOperationLegal(LoOpt.getOpcode(), LoOpt.getValueType()))) 1633 return CombineTo(N, LoOpt, LoOpt); 1634 } 1635 1636 if (HiExists) { 1637 SDValue Hi = DAG.getNode(HiOp, N->getDebugLoc(), N->getValueType(1), 1638 N->op_begin(), N->getNumOperands()); 1639 AddToWorkList(Hi.getNode()); 1640 SDValue HiOpt = combine(Hi.getNode()); 1641 if (HiOpt.getNode() && HiOpt != Hi && 1642 (!LegalOperations || 1643 TLI.isOperationLegal(HiOpt.getOpcode(), HiOpt.getValueType()))) 1644 return CombineTo(N, HiOpt, HiOpt); 1645 } 1646 1647 return SDValue(); 1648} 1649 1650SDValue DAGCombiner::visitSMUL_LOHI(SDNode *N) { 1651 SDValue Res = SimplifyNodeWithTwoResults(N, ISD::MUL, ISD::MULHS); 1652 if (Res.getNode()) return Res; 1653 1654 return SDValue(); 1655} 1656 1657SDValue DAGCombiner::visitUMUL_LOHI(SDNode *N) { 1658 SDValue Res = SimplifyNodeWithTwoResults(N, ISD::MUL, ISD::MULHU); 1659 if (Res.getNode()) return Res; 1660 1661 return SDValue(); 1662} 1663 1664SDValue DAGCombiner::visitSDIVREM(SDNode *N) { 1665 SDValue Res = SimplifyNodeWithTwoResults(N, ISD::SDIV, ISD::SREM); 1666 if (Res.getNode()) return Res; 1667 1668 return SDValue(); 1669} 1670 1671SDValue DAGCombiner::visitUDIVREM(SDNode *N) { 1672 SDValue Res = SimplifyNodeWithTwoResults(N, ISD::UDIV, ISD::UREM); 1673 if (Res.getNode()) return Res; 1674 1675 return SDValue(); 1676} 1677 1678/// SimplifyBinOpWithSameOpcodeHands - If this is a binary operator with 1679/// two operands of the same opcode, try to simplify it. 1680SDValue DAGCombiner::SimplifyBinOpWithSameOpcodeHands(SDNode *N) { 1681 SDValue N0 = N->getOperand(0), N1 = N->getOperand(1); 1682 EVT VT = N0.getValueType(); 1683 assert(N0.getOpcode() == N1.getOpcode() && "Bad input!"); 1684 1685 // For each of OP in AND/OR/XOR: 1686 // fold (OP (zext x), (zext y)) -> (zext (OP x, y)) 1687 // fold (OP (sext x), (sext y)) -> (sext (OP x, y)) 1688 // fold (OP (aext x), (aext y)) -> (aext (OP x, y)) 1689 // fold (OP (trunc x), (trunc y)) -> (trunc (OP x, y)) (if trunc isn't free) 1690 if ((N0.getOpcode() == ISD::ZERO_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND|| 1691 N0.getOpcode() == ISD::SIGN_EXTEND || 1692 (N0.getOpcode() == ISD::TRUNCATE && 1693 !TLI.isTruncateFree(N0.getOperand(0).getValueType(), VT))) && 1694 N0.getOperand(0).getValueType() == N1.getOperand(0).getValueType() && 1695 (!LegalOperations || 1696 TLI.isOperationLegal(N->getOpcode(), N0.getOperand(0).getValueType()))) { 1697 SDValue ORNode = DAG.getNode(N->getOpcode(), N0.getDebugLoc(), 1698 N0.getOperand(0).getValueType(), 1699 N0.getOperand(0), N1.getOperand(0)); 1700 AddToWorkList(ORNode.getNode()); 1701 return DAG.getNode(N0.getOpcode(), N->getDebugLoc(), VT, ORNode); 1702 } 1703 1704 // For each of OP in SHL/SRL/SRA/AND... 1705 // fold (and (OP x, z), (OP y, z)) -> (OP (and x, y), z) 1706 // fold (or (OP x, z), (OP y, z)) -> (OP (or x, y), z) 1707 // fold (xor (OP x, z), (OP y, z)) -> (OP (xor x, y), z) 1708 if ((N0.getOpcode() == ISD::SHL || N0.getOpcode() == ISD::SRL || 1709 N0.getOpcode() == ISD::SRA || N0.getOpcode() == ISD::AND) && 1710 N0.getOperand(1) == N1.getOperand(1)) { 1711 SDValue ORNode = DAG.getNode(N->getOpcode(), N0.getDebugLoc(), 1712 N0.getOperand(0).getValueType(), 1713 N0.getOperand(0), N1.getOperand(0)); 1714 AddToWorkList(ORNode.getNode()); 1715 return DAG.getNode(N0.getOpcode(), N->getDebugLoc(), VT, 1716 ORNode, N0.getOperand(1)); 1717 } 1718 1719 return SDValue(); 1720} 1721 1722SDValue DAGCombiner::visitAND(SDNode *N) { 1723 SDValue N0 = N->getOperand(0); 1724 SDValue N1 = N->getOperand(1); 1725 SDValue LL, LR, RL, RR, CC0, CC1; 1726 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 1727 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1728 EVT VT = N1.getValueType(); 1729 unsigned BitWidth = VT.getSizeInBits(); 1730 1731 // fold vector ops 1732 if (VT.isVector()) { 1733 SDValue FoldedVOp = SimplifyVBinOp(N); 1734 if (FoldedVOp.getNode()) return FoldedVOp; 1735 } 1736 1737 // fold (and x, undef) -> 0 1738 if (N0.getOpcode() == ISD::UNDEF || N1.getOpcode() == ISD::UNDEF) 1739 return DAG.getConstant(0, VT); 1740 // fold (and c1, c2) -> c1&c2 1741 if (N0C && N1C) 1742 return DAG.FoldConstantArithmetic(ISD::AND, VT, N0C, N1C); 1743 // canonicalize constant to RHS 1744 if (N0C && !N1C) 1745 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, N1, N0); 1746 // fold (and x, -1) -> x 1747 if (N1C && N1C->isAllOnesValue()) 1748 return N0; 1749 // if (and x, c) is known to be zero, return 0 1750 if (N1C && DAG.MaskedValueIsZero(SDValue(N, 0), 1751 APInt::getAllOnesValue(BitWidth))) 1752 return DAG.getConstant(0, VT); 1753 // reassociate and 1754 SDValue RAND = ReassociateOps(ISD::AND, N->getDebugLoc(), N0, N1); 1755 if (RAND.getNode() != 0) 1756 return RAND; 1757 // fold (and (or x, 0xFFFF), 0xFF) -> 0xFF 1758 if (N1C && N0.getOpcode() == ISD::OR) 1759 if (ConstantSDNode *ORI = dyn_cast<ConstantSDNode>(N0.getOperand(1))) 1760 if ((ORI->getAPIntValue() & N1C->getAPIntValue()) == N1C->getAPIntValue()) 1761 return N1; 1762 // fold (and (any_ext V), c) -> (zero_ext V) if 'and' only clears top bits. 1763 if (N1C && N0.getOpcode() == ISD::ANY_EXTEND) { 1764 SDValue N0Op0 = N0.getOperand(0); 1765 APInt Mask = ~N1C->getAPIntValue(); 1766 Mask.trunc(N0Op0.getValueSizeInBits()); 1767 if (DAG.MaskedValueIsZero(N0Op0, Mask)) { 1768 SDValue Zext = DAG.getNode(ISD::ZERO_EXTEND, N->getDebugLoc(), 1769 N0.getValueType(), N0Op0); 1770 1771 // Replace uses of the AND with uses of the Zero extend node. 1772 CombineTo(N, Zext); 1773 1774 // We actually want to replace all uses of the any_extend with the 1775 // zero_extend, to avoid duplicating things. This will later cause this 1776 // AND to be folded. 1777 CombineTo(N0.getNode(), Zext); 1778 return SDValue(N, 0); // Return N so it doesn't get rechecked! 1779 } 1780 } 1781 // fold (and (setcc x), (setcc y)) -> (setcc (and x, y)) 1782 if (isSetCCEquivalent(N0, LL, LR, CC0) && isSetCCEquivalent(N1, RL, RR, CC1)){ 1783 ISD::CondCode Op0 = cast<CondCodeSDNode>(CC0)->get(); 1784 ISD::CondCode Op1 = cast<CondCodeSDNode>(CC1)->get(); 1785 1786 if (LR == RR && isa<ConstantSDNode>(LR) && Op0 == Op1 && 1787 LL.getValueType().isInteger()) { 1788 // fold (and (seteq X, 0), (seteq Y, 0)) -> (seteq (or X, Y), 0) 1789 if (cast<ConstantSDNode>(LR)->isNullValue() && Op1 == ISD::SETEQ) { 1790 SDValue ORNode = DAG.getNode(ISD::OR, N0.getDebugLoc(), 1791 LR.getValueType(), LL, RL); 1792 AddToWorkList(ORNode.getNode()); 1793 return DAG.getSetCC(N->getDebugLoc(), VT, ORNode, LR, Op1); 1794 } 1795 // fold (and (seteq X, -1), (seteq Y, -1)) -> (seteq (and X, Y), -1) 1796 if (cast<ConstantSDNode>(LR)->isAllOnesValue() && Op1 == ISD::SETEQ) { 1797 SDValue ANDNode = DAG.getNode(ISD::AND, N0.getDebugLoc(), 1798 LR.getValueType(), LL, RL); 1799 AddToWorkList(ANDNode.getNode()); 1800 return DAG.getSetCC(N->getDebugLoc(), VT, ANDNode, LR, Op1); 1801 } 1802 // fold (and (setgt X, -1), (setgt Y, -1)) -> (setgt (or X, Y), -1) 1803 if (cast<ConstantSDNode>(LR)->isAllOnesValue() && Op1 == ISD::SETGT) { 1804 SDValue ORNode = DAG.getNode(ISD::OR, N0.getDebugLoc(), 1805 LR.getValueType(), LL, RL); 1806 AddToWorkList(ORNode.getNode()); 1807 return DAG.getSetCC(N->getDebugLoc(), VT, ORNode, LR, Op1); 1808 } 1809 } 1810 // canonicalize equivalent to ll == rl 1811 if (LL == RR && LR == RL) { 1812 Op1 = ISD::getSetCCSwappedOperands(Op1); 1813 std::swap(RL, RR); 1814 } 1815 if (LL == RL && LR == RR) { 1816 bool isInteger = LL.getValueType().isInteger(); 1817 ISD::CondCode Result = ISD::getSetCCAndOperation(Op0, Op1, isInteger); 1818 if (Result != ISD::SETCC_INVALID && 1819 (!LegalOperations || TLI.isCondCodeLegal(Result, LL.getValueType()))) 1820 return DAG.getSetCC(N->getDebugLoc(), N0.getValueType(), 1821 LL, LR, Result); 1822 } 1823 } 1824 1825 // Simplify: (and (op x...), (op y...)) -> (op (and x, y)) 1826 if (N0.getOpcode() == N1.getOpcode()) { 1827 SDValue Tmp = SimplifyBinOpWithSameOpcodeHands(N); 1828 if (Tmp.getNode()) return Tmp; 1829 } 1830 1831 // fold (and (sign_extend_inreg x, i16 to i32), 1) -> (and x, 1) 1832 // fold (and (sra)) -> (and (srl)) when possible. 1833 if (!VT.isVector() && 1834 SimplifyDemandedBits(SDValue(N, 0))) 1835 return SDValue(N, 0); 1836 // fold (zext_inreg (extload x)) -> (zextload x) 1837 if (ISD::isEXTLoad(N0.getNode()) && ISD::isUNINDEXEDLoad(N0.getNode())) { 1838 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 1839 EVT MemVT = LN0->getMemoryVT(); 1840 // If we zero all the possible extended bits, then we can turn this into 1841 // a zextload if we are running before legalize or the operation is legal. 1842 unsigned BitWidth = N1.getValueSizeInBits(); 1843 if (DAG.MaskedValueIsZero(N1, APInt::getHighBitsSet(BitWidth, 1844 BitWidth - MemVT.getSizeInBits())) && 1845 ((!LegalOperations && !LN0->isVolatile()) || 1846 TLI.isLoadExtLegal(ISD::ZEXTLOAD, MemVT))) { 1847 SDValue ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, N0.getDebugLoc(), VT, 1848 LN0->getChain(), LN0->getBasePtr(), 1849 LN0->getSrcValue(), 1850 LN0->getSrcValueOffset(), MemVT, 1851 LN0->isVolatile(), LN0->getAlignment()); 1852 AddToWorkList(N); 1853 CombineTo(N0.getNode(), ExtLoad, ExtLoad.getValue(1)); 1854 return SDValue(N, 0); // Return N so it doesn't get rechecked! 1855 } 1856 } 1857 // fold (zext_inreg (sextload x)) -> (zextload x) iff load has one use 1858 if (ISD::isSEXTLoad(N0.getNode()) && ISD::isUNINDEXEDLoad(N0.getNode()) && 1859 N0.hasOneUse()) { 1860 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 1861 EVT MemVT = LN0->getMemoryVT(); 1862 // If we zero all the possible extended bits, then we can turn this into 1863 // a zextload if we are running before legalize or the operation is legal. 1864 unsigned BitWidth = N1.getValueSizeInBits(); 1865 if (DAG.MaskedValueIsZero(N1, APInt::getHighBitsSet(BitWidth, 1866 BitWidth - MemVT.getSizeInBits())) && 1867 ((!LegalOperations && !LN0->isVolatile()) || 1868 TLI.isLoadExtLegal(ISD::ZEXTLOAD, MemVT))) { 1869 SDValue ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, N0.getDebugLoc(), VT, 1870 LN0->getChain(), 1871 LN0->getBasePtr(), LN0->getSrcValue(), 1872 LN0->getSrcValueOffset(), MemVT, 1873 LN0->isVolatile(), LN0->getAlignment()); 1874 AddToWorkList(N); 1875 CombineTo(N0.getNode(), ExtLoad, ExtLoad.getValue(1)); 1876 return SDValue(N, 0); // Return N so it doesn't get rechecked! 1877 } 1878 } 1879 1880 // fold (and (load x), 255) -> (zextload x, i8) 1881 // fold (and (extload x, i16), 255) -> (zextload x, i8) 1882 if (N1C && N0.getOpcode() == ISD::LOAD) { 1883 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 1884 if (LN0->getExtensionType() != ISD::SEXTLOAD && 1885 LN0->isUnindexed() && N0.hasOneUse() && 1886 // Do not change the width of a volatile load. 1887 !LN0->isVolatile()) { 1888 EVT ExtVT = MVT::Other; 1889 uint32_t ActiveBits = N1C->getAPIntValue().getActiveBits(); 1890 if (ActiveBits > 0 && APIntOps::isMask(ActiveBits, N1C->getAPIntValue())) 1891 ExtVT = EVT::getIntegerVT(*DAG.getContext(), ActiveBits); 1892 1893 EVT LoadedVT = LN0->getMemoryVT(); 1894 1895 // Do not generate loads of non-round integer types since these can 1896 // be expensive (and would be wrong if the type is not byte sized). 1897 if (ExtVT != MVT::Other && LoadedVT.bitsGT(ExtVT) && ExtVT.isRound() && 1898 (!LegalOperations || TLI.isLoadExtLegal(ISD::ZEXTLOAD, ExtVT))) { 1899 EVT PtrType = N0.getOperand(1).getValueType(); 1900 1901 // For big endian targets, we need to add an offset to the pointer to 1902 // load the correct bytes. For little endian systems, we merely need to 1903 // read fewer bytes from the same pointer. 1904 unsigned LVTStoreBytes = LoadedVT.getStoreSize(); 1905 unsigned EVTStoreBytes = ExtVT.getStoreSize(); 1906 unsigned PtrOff = LVTStoreBytes - EVTStoreBytes; 1907 unsigned Alignment = LN0->getAlignment(); 1908 SDValue NewPtr = LN0->getBasePtr(); 1909 1910 if (TLI.isBigEndian()) { 1911 NewPtr = DAG.getNode(ISD::ADD, LN0->getDebugLoc(), PtrType, 1912 NewPtr, DAG.getConstant(PtrOff, PtrType)); 1913 Alignment = MinAlign(Alignment, PtrOff); 1914 } 1915 1916 AddToWorkList(NewPtr.getNode()); 1917 SDValue Load = 1918 DAG.getExtLoad(ISD::ZEXTLOAD, LN0->getDebugLoc(), VT, LN0->getChain(), 1919 NewPtr, LN0->getSrcValue(), LN0->getSrcValueOffset(), 1920 ExtVT, LN0->isVolatile(), Alignment); 1921 AddToWorkList(N); 1922 CombineTo(N0.getNode(), Load, Load.getValue(1)); 1923 return SDValue(N, 0); // Return N so it doesn't get rechecked! 1924 } 1925 } 1926 } 1927 1928 return SDValue(); 1929} 1930 1931SDValue DAGCombiner::visitOR(SDNode *N) { 1932 SDValue N0 = N->getOperand(0); 1933 SDValue N1 = N->getOperand(1); 1934 SDValue LL, LR, RL, RR, CC0, CC1; 1935 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 1936 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1937 EVT VT = N1.getValueType(); 1938 1939 // fold vector ops 1940 if (VT.isVector()) { 1941 SDValue FoldedVOp = SimplifyVBinOp(N); 1942 if (FoldedVOp.getNode()) return FoldedVOp; 1943 } 1944 1945 // fold (or x, undef) -> -1 1946 if (N0.getOpcode() == ISD::UNDEF || N1.getOpcode() == ISD::UNDEF) 1947 return DAG.getConstant(APInt::getAllOnesValue(VT.getSizeInBits()), VT); 1948 // fold (or c1, c2) -> c1|c2 1949 if (N0C && N1C) 1950 return DAG.FoldConstantArithmetic(ISD::OR, VT, N0C, N1C); 1951 // canonicalize constant to RHS 1952 if (N0C && !N1C) 1953 return DAG.getNode(ISD::OR, N->getDebugLoc(), VT, N1, N0); 1954 // fold (or x, 0) -> x 1955 if (N1C && N1C->isNullValue()) 1956 return N0; 1957 // fold (or x, -1) -> -1 1958 if (N1C && N1C->isAllOnesValue()) 1959 return N1; 1960 // fold (or x, c) -> c iff (x & ~c) == 0 1961 if (N1C && DAG.MaskedValueIsZero(N0, ~N1C->getAPIntValue())) 1962 return N1; 1963 // reassociate or 1964 SDValue ROR = ReassociateOps(ISD::OR, N->getDebugLoc(), N0, N1); 1965 if (ROR.getNode() != 0) 1966 return ROR; 1967 // Canonicalize (or (and X, c1), c2) -> (and (or X, c2), c1|c2) 1968 if (N1C && N0.getOpcode() == ISD::AND && N0.getNode()->hasOneUse() && 1969 isa<ConstantSDNode>(N0.getOperand(1))) { 1970 ConstantSDNode *C1 = cast<ConstantSDNode>(N0.getOperand(1)); 1971 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, 1972 DAG.getNode(ISD::OR, N0.getDebugLoc(), VT, 1973 N0.getOperand(0), N1), 1974 DAG.FoldConstantArithmetic(ISD::OR, VT, N1C, C1)); 1975 } 1976 // fold (or (setcc x), (setcc y)) -> (setcc (or x, y)) 1977 if (isSetCCEquivalent(N0, LL, LR, CC0) && isSetCCEquivalent(N1, RL, RR, CC1)){ 1978 ISD::CondCode Op0 = cast<CondCodeSDNode>(CC0)->get(); 1979 ISD::CondCode Op1 = cast<CondCodeSDNode>(CC1)->get(); 1980 1981 if (LR == RR && isa<ConstantSDNode>(LR) && Op0 == Op1 && 1982 LL.getValueType().isInteger()) { 1983 // fold (or (setne X, 0), (setne Y, 0)) -> (setne (or X, Y), 0) 1984 // fold (or (setlt X, 0), (setlt Y, 0)) -> (setne (or X, Y), 0) 1985 if (cast<ConstantSDNode>(LR)->isNullValue() && 1986 (Op1 == ISD::SETNE || Op1 == ISD::SETLT)) { 1987 SDValue ORNode = DAG.getNode(ISD::OR, LR.getDebugLoc(), 1988 LR.getValueType(), LL, RL); 1989 AddToWorkList(ORNode.getNode()); 1990 return DAG.getSetCC(N->getDebugLoc(), VT, ORNode, LR, Op1); 1991 } 1992 // fold (or (setne X, -1), (setne Y, -1)) -> (setne (and X, Y), -1) 1993 // fold (or (setgt X, -1), (setgt Y -1)) -> (setgt (and X, Y), -1) 1994 if (cast<ConstantSDNode>(LR)->isAllOnesValue() && 1995 (Op1 == ISD::SETNE || Op1 == ISD::SETGT)) { 1996 SDValue ANDNode = DAG.getNode(ISD::AND, LR.getDebugLoc(), 1997 LR.getValueType(), LL, RL); 1998 AddToWorkList(ANDNode.getNode()); 1999 return DAG.getSetCC(N->getDebugLoc(), VT, ANDNode, LR, Op1); 2000 } 2001 } 2002 // canonicalize equivalent to ll == rl 2003 if (LL == RR && LR == RL) { 2004 Op1 = ISD::getSetCCSwappedOperands(Op1); 2005 std::swap(RL, RR); 2006 } 2007 if (LL == RL && LR == RR) { 2008 bool isInteger = LL.getValueType().isInteger(); 2009 ISD::CondCode Result = ISD::getSetCCOrOperation(Op0, Op1, isInteger); 2010 if (Result != ISD::SETCC_INVALID && 2011 (!LegalOperations || TLI.isCondCodeLegal(Result, LL.getValueType()))) 2012 return DAG.getSetCC(N->getDebugLoc(), N0.getValueType(), 2013 LL, LR, Result); 2014 } 2015 } 2016 2017 // Simplify: (or (op x...), (op y...)) -> (op (or x, y)) 2018 if (N0.getOpcode() == N1.getOpcode()) { 2019 SDValue Tmp = SimplifyBinOpWithSameOpcodeHands(N); 2020 if (Tmp.getNode()) return Tmp; 2021 } 2022 2023 // (or (and X, C1), (and Y, C2)) -> (and (or X, Y), C3) if possible. 2024 if (N0.getOpcode() == ISD::AND && 2025 N1.getOpcode() == ISD::AND && 2026 N0.getOperand(1).getOpcode() == ISD::Constant && 2027 N1.getOperand(1).getOpcode() == ISD::Constant && 2028 // Don't increase # computations. 2029 (N0.getNode()->hasOneUse() || N1.getNode()->hasOneUse())) { 2030 // We can only do this xform if we know that bits from X that are set in C2 2031 // but not in C1 are already zero. Likewise for Y. 2032 const APInt &LHSMask = 2033 cast<ConstantSDNode>(N0.getOperand(1))->getAPIntValue(); 2034 const APInt &RHSMask = 2035 cast<ConstantSDNode>(N1.getOperand(1))->getAPIntValue(); 2036 2037 if (DAG.MaskedValueIsZero(N0.getOperand(0), RHSMask&~LHSMask) && 2038 DAG.MaskedValueIsZero(N1.getOperand(0), LHSMask&~RHSMask)) { 2039 SDValue X = DAG.getNode(ISD::OR, N0.getDebugLoc(), VT, 2040 N0.getOperand(0), N1.getOperand(0)); 2041 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, X, 2042 DAG.getConstant(LHSMask | RHSMask, VT)); 2043 } 2044 } 2045 2046 // See if this is some rotate idiom. 2047 if (SDNode *Rot = MatchRotate(N0, N1, N->getDebugLoc())) 2048 return SDValue(Rot, 0); 2049 2050 return SDValue(); 2051} 2052 2053/// MatchRotateHalf - Match "(X shl/srl V1) & V2" where V2 may not be present. 2054static bool MatchRotateHalf(SDValue Op, SDValue &Shift, SDValue &Mask) { 2055 if (Op.getOpcode() == ISD::AND) { 2056 if (isa<ConstantSDNode>(Op.getOperand(1))) { 2057 Mask = Op.getOperand(1); 2058 Op = Op.getOperand(0); 2059 } else { 2060 return false; 2061 } 2062 } 2063 2064 if (Op.getOpcode() == ISD::SRL || Op.getOpcode() == ISD::SHL) { 2065 Shift = Op; 2066 return true; 2067 } 2068 2069 return false; 2070} 2071 2072// MatchRotate - Handle an 'or' of two operands. If this is one of the many 2073// idioms for rotate, and if the target supports rotation instructions, generate 2074// a rot[lr]. 2075SDNode *DAGCombiner::MatchRotate(SDValue LHS, SDValue RHS, DebugLoc DL) { 2076 // Must be a legal type. Expanded 'n promoted things won't work with rotates. 2077 EVT VT = LHS.getValueType(); 2078 if (!TLI.isTypeLegal(VT)) return 0; 2079 2080 // The target must have at least one rotate flavor. 2081 bool HasROTL = TLI.isOperationLegalOrCustom(ISD::ROTL, VT); 2082 bool HasROTR = TLI.isOperationLegalOrCustom(ISD::ROTR, VT); 2083 if (!HasROTL && !HasROTR) return 0; 2084 2085 // Match "(X shl/srl V1) & V2" where V2 may not be present. 2086 SDValue LHSShift; // The shift. 2087 SDValue LHSMask; // AND value if any. 2088 if (!MatchRotateHalf(LHS, LHSShift, LHSMask)) 2089 return 0; // Not part of a rotate. 2090 2091 SDValue RHSShift; // The shift. 2092 SDValue RHSMask; // AND value if any. 2093 if (!MatchRotateHalf(RHS, RHSShift, RHSMask)) 2094 return 0; // Not part of a rotate. 2095 2096 if (LHSShift.getOperand(0) != RHSShift.getOperand(0)) 2097 return 0; // Not shifting the same value. 2098 2099 if (LHSShift.getOpcode() == RHSShift.getOpcode()) 2100 return 0; // Shifts must disagree. 2101 2102 // Canonicalize shl to left side in a shl/srl pair. 2103 if (RHSShift.getOpcode() == ISD::SHL) { 2104 std::swap(LHS, RHS); 2105 std::swap(LHSShift, RHSShift); 2106 std::swap(LHSMask , RHSMask ); 2107 } 2108 2109 unsigned OpSizeInBits = VT.getSizeInBits(); 2110 SDValue LHSShiftArg = LHSShift.getOperand(0); 2111 SDValue LHSShiftAmt = LHSShift.getOperand(1); 2112 SDValue RHSShiftAmt = RHSShift.getOperand(1); 2113 2114 // fold (or (shl x, C1), (srl x, C2)) -> (rotl x, C1) 2115 // fold (or (shl x, C1), (srl x, C2)) -> (rotr x, C2) 2116 if (LHSShiftAmt.getOpcode() == ISD::Constant && 2117 RHSShiftAmt.getOpcode() == ISD::Constant) { 2118 uint64_t LShVal = cast<ConstantSDNode>(LHSShiftAmt)->getZExtValue(); 2119 uint64_t RShVal = cast<ConstantSDNode>(RHSShiftAmt)->getZExtValue(); 2120 if ((LShVal + RShVal) != OpSizeInBits) 2121 return 0; 2122 2123 SDValue Rot; 2124 if (HasROTL) 2125 Rot = DAG.getNode(ISD::ROTL, DL, VT, LHSShiftArg, LHSShiftAmt); 2126 else 2127 Rot = DAG.getNode(ISD::ROTR, DL, VT, LHSShiftArg, RHSShiftAmt); 2128 2129 // If there is an AND of either shifted operand, apply it to the result. 2130 if (LHSMask.getNode() || RHSMask.getNode()) { 2131 APInt Mask = APInt::getAllOnesValue(OpSizeInBits); 2132 2133 if (LHSMask.getNode()) { 2134 APInt RHSBits = APInt::getLowBitsSet(OpSizeInBits, LShVal); 2135 Mask &= cast<ConstantSDNode>(LHSMask)->getAPIntValue() | RHSBits; 2136 } 2137 if (RHSMask.getNode()) { 2138 APInt LHSBits = APInt::getHighBitsSet(OpSizeInBits, RShVal); 2139 Mask &= cast<ConstantSDNode>(RHSMask)->getAPIntValue() | LHSBits; 2140 } 2141 2142 Rot = DAG.getNode(ISD::AND, DL, VT, Rot, DAG.getConstant(Mask, VT)); 2143 } 2144 2145 return Rot.getNode(); 2146 } 2147 2148 // If there is a mask here, and we have a variable shift, we can't be sure 2149 // that we're masking out the right stuff. 2150 if (LHSMask.getNode() || RHSMask.getNode()) 2151 return 0; 2152 2153 // fold (or (shl x, y), (srl x, (sub 32, y))) -> (rotl x, y) 2154 // fold (or (shl x, y), (srl x, (sub 32, y))) -> (rotr x, (sub 32, y)) 2155 if (RHSShiftAmt.getOpcode() == ISD::SUB && 2156 LHSShiftAmt == RHSShiftAmt.getOperand(1)) { 2157 if (ConstantSDNode *SUBC = 2158 dyn_cast<ConstantSDNode>(RHSShiftAmt.getOperand(0))) { 2159 if (SUBC->getAPIntValue() == OpSizeInBits) { 2160 if (HasROTL) 2161 return DAG.getNode(ISD::ROTL, DL, VT, 2162 LHSShiftArg, LHSShiftAmt).getNode(); 2163 else 2164 return DAG.getNode(ISD::ROTR, DL, VT, 2165 LHSShiftArg, RHSShiftAmt).getNode(); 2166 } 2167 } 2168 } 2169 2170 // fold (or (shl x, (sub 32, y)), (srl x, r)) -> (rotr x, y) 2171 // fold (or (shl x, (sub 32, y)), (srl x, r)) -> (rotl x, (sub 32, y)) 2172 if (LHSShiftAmt.getOpcode() == ISD::SUB && 2173 RHSShiftAmt == LHSShiftAmt.getOperand(1)) { 2174 if (ConstantSDNode *SUBC = 2175 dyn_cast<ConstantSDNode>(LHSShiftAmt.getOperand(0))) { 2176 if (SUBC->getAPIntValue() == OpSizeInBits) { 2177 if (HasROTR) 2178 return DAG.getNode(ISD::ROTR, DL, VT, 2179 LHSShiftArg, RHSShiftAmt).getNode(); 2180 else 2181 return DAG.getNode(ISD::ROTL, DL, VT, 2182 LHSShiftArg, LHSShiftAmt).getNode(); 2183 } 2184 } 2185 } 2186 2187 // Look for sign/zext/any-extended or truncate cases: 2188 if ((LHSShiftAmt.getOpcode() == ISD::SIGN_EXTEND 2189 || LHSShiftAmt.getOpcode() == ISD::ZERO_EXTEND 2190 || LHSShiftAmt.getOpcode() == ISD::ANY_EXTEND 2191 || LHSShiftAmt.getOpcode() == ISD::TRUNCATE) && 2192 (RHSShiftAmt.getOpcode() == ISD::SIGN_EXTEND 2193 || RHSShiftAmt.getOpcode() == ISD::ZERO_EXTEND 2194 || RHSShiftAmt.getOpcode() == ISD::ANY_EXTEND 2195 || RHSShiftAmt.getOpcode() == ISD::TRUNCATE)) { 2196 SDValue LExtOp0 = LHSShiftAmt.getOperand(0); 2197 SDValue RExtOp0 = RHSShiftAmt.getOperand(0); 2198 if (RExtOp0.getOpcode() == ISD::SUB && 2199 RExtOp0.getOperand(1) == LExtOp0) { 2200 // fold (or (shl x, (*ext y)), (srl x, (*ext (sub 32, y)))) -> 2201 // (rotl x, y) 2202 // fold (or (shl x, (*ext y)), (srl x, (*ext (sub 32, y)))) -> 2203 // (rotr x, (sub 32, y)) 2204 if (ConstantSDNode *SUBC = 2205 dyn_cast<ConstantSDNode>(RExtOp0.getOperand(0))) { 2206 if (SUBC->getAPIntValue() == OpSizeInBits) { 2207 return DAG.getNode(HasROTL ? ISD::ROTL : ISD::ROTR, DL, VT, 2208 LHSShiftArg, 2209 HasROTL ? LHSShiftAmt : RHSShiftAmt).getNode(); 2210 } 2211 } 2212 } else if (LExtOp0.getOpcode() == ISD::SUB && 2213 RExtOp0 == LExtOp0.getOperand(1)) { 2214 // fold (or (shl x, (*ext (sub 32, y))), (srl x, (*ext y))) -> 2215 // (rotr x, y) 2216 // fold (or (shl x, (*ext (sub 32, y))), (srl x, (*ext y))) -> 2217 // (rotl x, (sub 32, y)) 2218 if (ConstantSDNode *SUBC = 2219 dyn_cast<ConstantSDNode>(LExtOp0.getOperand(0))) { 2220 if (SUBC->getAPIntValue() == OpSizeInBits) { 2221 return DAG.getNode(HasROTR ? ISD::ROTR : ISD::ROTL, DL, VT, 2222 LHSShiftArg, 2223 HasROTR ? RHSShiftAmt : LHSShiftAmt).getNode(); 2224 } 2225 } 2226 } 2227 } 2228 2229 return 0; 2230} 2231 2232SDValue DAGCombiner::visitXOR(SDNode *N) { 2233 SDValue N0 = N->getOperand(0); 2234 SDValue N1 = N->getOperand(1); 2235 SDValue LHS, RHS, CC; 2236 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 2237 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 2238 EVT VT = N0.getValueType(); 2239 2240 // fold vector ops 2241 if (VT.isVector()) { 2242 SDValue FoldedVOp = SimplifyVBinOp(N); 2243 if (FoldedVOp.getNode()) return FoldedVOp; 2244 } 2245 2246 // fold (xor undef, undef) -> 0. This is a common idiom (misuse). 2247 if (N0.getOpcode() == ISD::UNDEF && N1.getOpcode() == ISD::UNDEF) 2248 return DAG.getConstant(0, VT); 2249 // fold (xor x, undef) -> undef 2250 if (N0.getOpcode() == ISD::UNDEF) 2251 return N0; 2252 if (N1.getOpcode() == ISD::UNDEF) 2253 return N1; 2254 // fold (xor c1, c2) -> c1^c2 2255 if (N0C && N1C) 2256 return DAG.FoldConstantArithmetic(ISD::XOR, VT, N0C, N1C); 2257 // canonicalize constant to RHS 2258 if (N0C && !N1C) 2259 return DAG.getNode(ISD::XOR, N->getDebugLoc(), VT, N1, N0); 2260 // fold (xor x, 0) -> x 2261 if (N1C && N1C->isNullValue()) 2262 return N0; 2263 // reassociate xor 2264 SDValue RXOR = ReassociateOps(ISD::XOR, N->getDebugLoc(), N0, N1); 2265 if (RXOR.getNode() != 0) 2266 return RXOR; 2267 2268 // fold !(x cc y) -> (x !cc y) 2269 if (N1C && N1C->getAPIntValue() == 1 && isSetCCEquivalent(N0, LHS, RHS, CC)) { 2270 bool isInt = LHS.getValueType().isInteger(); 2271 ISD::CondCode NotCC = ISD::getSetCCInverse(cast<CondCodeSDNode>(CC)->get(), 2272 isInt); 2273 2274 if (!LegalOperations || TLI.isCondCodeLegal(NotCC, LHS.getValueType())) { 2275 switch (N0.getOpcode()) { 2276 default: 2277 llvm_unreachable("Unhandled SetCC Equivalent!"); 2278 case ISD::SETCC: 2279 return DAG.getSetCC(N->getDebugLoc(), VT, LHS, RHS, NotCC); 2280 case ISD::SELECT_CC: 2281 return DAG.getSelectCC(N->getDebugLoc(), LHS, RHS, N0.getOperand(2), 2282 N0.getOperand(3), NotCC); 2283 } 2284 } 2285 } 2286 2287 // fold (not (zext (setcc x, y))) -> (zext (not (setcc x, y))) 2288 if (N1C && N1C->getAPIntValue() == 1 && N0.getOpcode() == ISD::ZERO_EXTEND && 2289 N0.getNode()->hasOneUse() && 2290 isSetCCEquivalent(N0.getOperand(0), LHS, RHS, CC)){ 2291 SDValue V = N0.getOperand(0); 2292 V = DAG.getNode(ISD::XOR, N0.getDebugLoc(), V.getValueType(), V, 2293 DAG.getConstant(1, V.getValueType())); 2294 AddToWorkList(V.getNode()); 2295 return DAG.getNode(ISD::ZERO_EXTEND, N->getDebugLoc(), VT, V); 2296 } 2297 2298 // fold (not (or x, y)) -> (and (not x), (not y)) iff x or y are setcc 2299 if (N1C && N1C->getAPIntValue() == 1 && VT == MVT::i1 && 2300 (N0.getOpcode() == ISD::OR || N0.getOpcode() == ISD::AND)) { 2301 SDValue LHS = N0.getOperand(0), RHS = N0.getOperand(1); 2302 if (isOneUseSetCC(RHS) || isOneUseSetCC(LHS)) { 2303 unsigned NewOpcode = N0.getOpcode() == ISD::AND ? ISD::OR : ISD::AND; 2304 LHS = DAG.getNode(ISD::XOR, LHS.getDebugLoc(), VT, LHS, N1); // LHS = ~LHS 2305 RHS = DAG.getNode(ISD::XOR, RHS.getDebugLoc(), VT, RHS, N1); // RHS = ~RHS 2306 AddToWorkList(LHS.getNode()); AddToWorkList(RHS.getNode()); 2307 return DAG.getNode(NewOpcode, N->getDebugLoc(), VT, LHS, RHS); 2308 } 2309 } 2310 // fold (not (or x, y)) -> (and (not x), (not y)) iff x or y are constants 2311 if (N1C && N1C->isAllOnesValue() && 2312 (N0.getOpcode() == ISD::OR || N0.getOpcode() == ISD::AND)) { 2313 SDValue LHS = N0.getOperand(0), RHS = N0.getOperand(1); 2314 if (isa<ConstantSDNode>(RHS) || isa<ConstantSDNode>(LHS)) { 2315 unsigned NewOpcode = N0.getOpcode() == ISD::AND ? ISD::OR : ISD::AND; 2316 LHS = DAG.getNode(ISD::XOR, LHS.getDebugLoc(), VT, LHS, N1); // LHS = ~LHS 2317 RHS = DAG.getNode(ISD::XOR, RHS.getDebugLoc(), VT, RHS, N1); // RHS = ~RHS 2318 AddToWorkList(LHS.getNode()); AddToWorkList(RHS.getNode()); 2319 return DAG.getNode(NewOpcode, N->getDebugLoc(), VT, LHS, RHS); 2320 } 2321 } 2322 // fold (xor (xor x, c1), c2) -> (xor x, (xor c1, c2)) 2323 if (N1C && N0.getOpcode() == ISD::XOR) { 2324 ConstantSDNode *N00C = dyn_cast<ConstantSDNode>(N0.getOperand(0)); 2325 ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N0.getOperand(1)); 2326 if (N00C) 2327 return DAG.getNode(ISD::XOR, N->getDebugLoc(), VT, N0.getOperand(1), 2328 DAG.getConstant(N1C->getAPIntValue() ^ 2329 N00C->getAPIntValue(), VT)); 2330 if (N01C) 2331 return DAG.getNode(ISD::XOR, N->getDebugLoc(), VT, N0.getOperand(0), 2332 DAG.getConstant(N1C->getAPIntValue() ^ 2333 N01C->getAPIntValue(), VT)); 2334 } 2335 // fold (xor x, x) -> 0 2336 if (N0 == N1) { 2337 if (!VT.isVector()) { 2338 return DAG.getConstant(0, VT); 2339 } else if (!LegalOperations || TLI.isOperationLegal(ISD::BUILD_VECTOR, VT)){ 2340 // Produce a vector of zeros. 2341 SDValue El = DAG.getConstant(0, VT.getVectorElementType()); 2342 std::vector<SDValue> Ops(VT.getVectorNumElements(), El); 2343 return DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(), VT, 2344 &Ops[0], Ops.size()); 2345 } 2346 } 2347 2348 // Simplify: xor (op x...), (op y...) -> (op (xor x, y)) 2349 if (N0.getOpcode() == N1.getOpcode()) { 2350 SDValue Tmp = SimplifyBinOpWithSameOpcodeHands(N); 2351 if (Tmp.getNode()) return Tmp; 2352 } 2353 2354 // Simplify the expression using non-local knowledge. 2355 if (!VT.isVector() && 2356 SimplifyDemandedBits(SDValue(N, 0))) 2357 return SDValue(N, 0); 2358 2359 return SDValue(); 2360} 2361 2362/// visitShiftByConstant - Handle transforms common to the three shifts, when 2363/// the shift amount is a constant. 2364SDValue DAGCombiner::visitShiftByConstant(SDNode *N, unsigned Amt) { 2365 SDNode *LHS = N->getOperand(0).getNode(); 2366 if (!LHS->hasOneUse()) return SDValue(); 2367 2368 // We want to pull some binops through shifts, so that we have (and (shift)) 2369 // instead of (shift (and)), likewise for add, or, xor, etc. This sort of 2370 // thing happens with address calculations, so it's important to canonicalize 2371 // it. 2372 bool HighBitSet = false; // Can we transform this if the high bit is set? 2373 2374 switch (LHS->getOpcode()) { 2375 default: return SDValue(); 2376 case ISD::OR: 2377 case ISD::XOR: 2378 HighBitSet = false; // We can only transform sra if the high bit is clear. 2379 break; 2380 case ISD::AND: 2381 HighBitSet = true; // We can only transform sra if the high bit is set. 2382 break; 2383 case ISD::ADD: 2384 if (N->getOpcode() != ISD::SHL) 2385 return SDValue(); // only shl(add) not sr[al](add). 2386 HighBitSet = false; // We can only transform sra if the high bit is clear. 2387 break; 2388 } 2389 2390 // We require the RHS of the binop to be a constant as well. 2391 ConstantSDNode *BinOpCst = dyn_cast<ConstantSDNode>(LHS->getOperand(1)); 2392 if (!BinOpCst) return SDValue(); 2393 2394 // FIXME: disable this unless the input to the binop is a shift by a constant. 2395 // If it is not a shift, it pessimizes some common cases like: 2396 // 2397 // void foo(int *X, int i) { X[i & 1235] = 1; } 2398 // int bar(int *X, int i) { return X[i & 255]; } 2399 SDNode *BinOpLHSVal = LHS->getOperand(0).getNode(); 2400 if ((BinOpLHSVal->getOpcode() != ISD::SHL && 2401 BinOpLHSVal->getOpcode() != ISD::SRA && 2402 BinOpLHSVal->getOpcode() != ISD::SRL) || 2403 !isa<ConstantSDNode>(BinOpLHSVal->getOperand(1))) 2404 return SDValue(); 2405 2406 EVT VT = N->getValueType(0); 2407 2408 // If this is a signed shift right, and the high bit is modified by the 2409 // logical operation, do not perform the transformation. The highBitSet 2410 // boolean indicates the value of the high bit of the constant which would 2411 // cause it to be modified for this operation. 2412 if (N->getOpcode() == ISD::SRA) { 2413 bool BinOpRHSSignSet = BinOpCst->getAPIntValue().isNegative(); 2414 if (BinOpRHSSignSet != HighBitSet) 2415 return SDValue(); 2416 } 2417 2418 // Fold the constants, shifting the binop RHS by the shift amount. 2419 SDValue NewRHS = DAG.getNode(N->getOpcode(), LHS->getOperand(1).getDebugLoc(), 2420 N->getValueType(0), 2421 LHS->getOperand(1), N->getOperand(1)); 2422 2423 // Create the new shift. 2424 SDValue NewShift = DAG.getNode(N->getOpcode(), LHS->getOperand(0).getDebugLoc(), 2425 VT, LHS->getOperand(0), N->getOperand(1)); 2426 2427 // Create the new binop. 2428 return DAG.getNode(LHS->getOpcode(), N->getDebugLoc(), VT, NewShift, NewRHS); 2429} 2430 2431SDValue DAGCombiner::visitSHL(SDNode *N) { 2432 SDValue N0 = N->getOperand(0); 2433 SDValue N1 = N->getOperand(1); 2434 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 2435 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 2436 EVT VT = N0.getValueType(); 2437 unsigned OpSizeInBits = VT.getSizeInBits(); 2438 2439 // fold (shl c1, c2) -> c1<<c2 2440 if (N0C && N1C) 2441 return DAG.FoldConstantArithmetic(ISD::SHL, VT, N0C, N1C); 2442 // fold (shl 0, x) -> 0 2443 if (N0C && N0C->isNullValue()) 2444 return N0; 2445 // fold (shl x, c >= size(x)) -> undef 2446 if (N1C && N1C->getZExtValue() >= OpSizeInBits) 2447 return DAG.getUNDEF(VT); 2448 // fold (shl x, 0) -> x 2449 if (N1C && N1C->isNullValue()) 2450 return N0; 2451 // if (shl x, c) is known to be zero, return 0 2452 if (DAG.MaskedValueIsZero(SDValue(N, 0), 2453 APInt::getAllOnesValue(VT.getSizeInBits()))) 2454 return DAG.getConstant(0, VT); 2455 // fold (shl x, (trunc (and y, c))) -> (shl x, (and (trunc y), (trunc c))). 2456 if (N1.getOpcode() == ISD::TRUNCATE && 2457 N1.getOperand(0).getOpcode() == ISD::AND && 2458 N1.hasOneUse() && N1.getOperand(0).hasOneUse()) { 2459 SDValue N101 = N1.getOperand(0).getOperand(1); 2460 if (ConstantSDNode *N101C = dyn_cast<ConstantSDNode>(N101)) { 2461 EVT TruncVT = N1.getValueType(); 2462 SDValue N100 = N1.getOperand(0).getOperand(0); 2463 APInt TruncC = N101C->getAPIntValue(); 2464 TruncC.trunc(TruncVT.getSizeInBits()); 2465 return DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, N0, 2466 DAG.getNode(ISD::AND, N->getDebugLoc(), TruncVT, 2467 DAG.getNode(ISD::TRUNCATE, 2468 N->getDebugLoc(), 2469 TruncVT, N100), 2470 DAG.getConstant(TruncC, TruncVT))); 2471 } 2472 } 2473 2474 if (N1C && SimplifyDemandedBits(SDValue(N, 0))) 2475 return SDValue(N, 0); 2476 2477 // fold (shl (shl x, c1), c2) -> 0 or (shl x, (add c1, c2)) 2478 if (N1C && N0.getOpcode() == ISD::SHL && 2479 N0.getOperand(1).getOpcode() == ISD::Constant) { 2480 uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getZExtValue(); 2481 uint64_t c2 = N1C->getZExtValue(); 2482 if (c1 + c2 > OpSizeInBits) 2483 return DAG.getConstant(0, VT); 2484 return DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, N0.getOperand(0), 2485 DAG.getConstant(c1 + c2, N1.getValueType())); 2486 } 2487 // fold (shl (srl x, c1), c2) -> (shl (and x, (shl -1, c1)), (sub c2, c1)) or 2488 // (srl (and x, (shl -1, c1)), (sub c1, c2)) 2489 if (N1C && N0.getOpcode() == ISD::SRL && 2490 N0.getOperand(1).getOpcode() == ISD::Constant) { 2491 uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getZExtValue(); 2492 if (c1 < VT.getSizeInBits()) { 2493 uint64_t c2 = N1C->getZExtValue(); 2494 SDValue HiBitsMask = 2495 DAG.getConstant(APInt::getHighBitsSet(VT.getSizeInBits(), 2496 VT.getSizeInBits() - c1), 2497 VT); 2498 SDValue Mask = DAG.getNode(ISD::AND, N0.getDebugLoc(), VT, 2499 N0.getOperand(0), 2500 HiBitsMask); 2501 if (c2 > c1) 2502 return DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, Mask, 2503 DAG.getConstant(c2-c1, N1.getValueType())); 2504 else 2505 return DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, Mask, 2506 DAG.getConstant(c1-c2, N1.getValueType())); 2507 } 2508 } 2509 // fold (shl (sra x, c1), c1) -> (and x, (shl -1, c1)) 2510 if (N1C && N0.getOpcode() == ISD::SRA && N1 == N0.getOperand(1)) { 2511 SDValue HiBitsMask = 2512 DAG.getConstant(APInt::getHighBitsSet(VT.getSizeInBits(), 2513 VT.getSizeInBits() - 2514 N1C->getZExtValue()), 2515 VT); 2516 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, N0.getOperand(0), 2517 HiBitsMask); 2518 } 2519 2520 return N1C ? visitShiftByConstant(N, N1C->getZExtValue()) : SDValue(); 2521} 2522 2523SDValue DAGCombiner::visitSRA(SDNode *N) { 2524 SDValue N0 = N->getOperand(0); 2525 SDValue N1 = N->getOperand(1); 2526 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 2527 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 2528 EVT VT = N0.getValueType(); 2529 2530 // fold (sra c1, c2) -> (sra c1, c2) 2531 if (N0C && N1C) 2532 return DAG.FoldConstantArithmetic(ISD::SRA, VT, N0C, N1C); 2533 // fold (sra 0, x) -> 0 2534 if (N0C && N0C->isNullValue()) 2535 return N0; 2536 // fold (sra -1, x) -> -1 2537 if (N0C && N0C->isAllOnesValue()) 2538 return N0; 2539 // fold (sra x, (setge c, size(x))) -> undef 2540 if (N1C && N1C->getZExtValue() >= VT.getSizeInBits()) 2541 return DAG.getUNDEF(VT); 2542 // fold (sra x, 0) -> x 2543 if (N1C && N1C->isNullValue()) 2544 return N0; 2545 // fold (sra (shl x, c1), c1) -> sext_inreg for some c1 and target supports 2546 // sext_inreg. 2547 if (N1C && N0.getOpcode() == ISD::SHL && N1 == N0.getOperand(1)) { 2548 unsigned LowBits = VT.getSizeInBits() - (unsigned)N1C->getZExtValue(); 2549 EVT EVT = EVT::getIntegerVT(*DAG.getContext(), LowBits); 2550 if ((!LegalOperations || TLI.isOperationLegal(ISD::SIGN_EXTEND_INREG, EVT))) 2551 return DAG.getNode(ISD::SIGN_EXTEND_INREG, N->getDebugLoc(), VT, 2552 N0.getOperand(0), DAG.getValueType(EVT)); 2553 } 2554 2555 // fold (sra (sra x, c1), c2) -> (sra x, (add c1, c2)) 2556 if (N1C && N0.getOpcode() == ISD::SRA) { 2557 if (ConstantSDNode *C1 = dyn_cast<ConstantSDNode>(N0.getOperand(1))) { 2558 unsigned Sum = N1C->getZExtValue() + C1->getZExtValue(); 2559 if (Sum >= VT.getSizeInBits()) Sum = VT.getSizeInBits()-1; 2560 return DAG.getNode(ISD::SRA, N->getDebugLoc(), VT, N0.getOperand(0), 2561 DAG.getConstant(Sum, N1C->getValueType(0))); 2562 } 2563 } 2564 2565 // fold (sra (shl X, m), (sub result_size, n)) 2566 // -> (sign_extend (trunc (shl X, (sub (sub result_size, n), m)))) for 2567 // result_size - n != m. 2568 // If truncate is free for the target sext(shl) is likely to result in better 2569 // code. 2570 if (N0.getOpcode() == ISD::SHL) { 2571 // Get the two constanst of the shifts, CN0 = m, CN = n. 2572 const ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N0.getOperand(1)); 2573 if (N01C && N1C) { 2574 // Determine what the truncate's result bitsize and type would be. 2575 unsigned VTValSize = VT.getSizeInBits(); 2576 EVT TruncVT = 2577 EVT::getIntegerVT(*DAG.getContext(), VTValSize - N1C->getZExtValue()); 2578 // Determine the residual right-shift amount. 2579 signed ShiftAmt = N1C->getZExtValue() - N01C->getZExtValue(); 2580 2581 // If the shift is not a no-op (in which case this should be just a sign 2582 // extend already), the truncated to type is legal, sign_extend is legal 2583 // on that type, and the the truncate to that type is both legal and free, 2584 // perform the transform. 2585 if ((ShiftAmt > 0) && 2586 TLI.isOperationLegalOrCustom(ISD::SIGN_EXTEND, TruncVT) && 2587 TLI.isOperationLegalOrCustom(ISD::TRUNCATE, VT) && 2588 TLI.isTruncateFree(VT, TruncVT)) { 2589 2590 SDValue Amt = DAG.getConstant(ShiftAmt, getShiftAmountTy()); 2591 SDValue Shift = DAG.getNode(ISD::SRL, N0.getDebugLoc(), VT, 2592 N0.getOperand(0), Amt); 2593 SDValue Trunc = DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(), TruncVT, 2594 Shift); 2595 return DAG.getNode(ISD::SIGN_EXTEND, N->getDebugLoc(), 2596 N->getValueType(0), Trunc); 2597 } 2598 } 2599 } 2600 2601 // fold (sra x, (trunc (and y, c))) -> (sra x, (and (trunc y), (trunc c))). 2602 if (N1.getOpcode() == ISD::TRUNCATE && 2603 N1.getOperand(0).getOpcode() == ISD::AND && 2604 N1.hasOneUse() && N1.getOperand(0).hasOneUse()) { 2605 SDValue N101 = N1.getOperand(0).getOperand(1); 2606 if (ConstantSDNode *N101C = dyn_cast<ConstantSDNode>(N101)) { 2607 EVT TruncVT = N1.getValueType(); 2608 SDValue N100 = N1.getOperand(0).getOperand(0); 2609 APInt TruncC = N101C->getAPIntValue(); 2610 TruncC.trunc(TruncVT.getSizeInBits()); 2611 return DAG.getNode(ISD::SRA, N->getDebugLoc(), VT, N0, 2612 DAG.getNode(ISD::AND, N->getDebugLoc(), 2613 TruncVT, 2614 DAG.getNode(ISD::TRUNCATE, 2615 N->getDebugLoc(), 2616 TruncVT, N100), 2617 DAG.getConstant(TruncC, TruncVT))); 2618 } 2619 } 2620 2621 // Simplify, based on bits shifted out of the LHS. 2622 if (N1C && SimplifyDemandedBits(SDValue(N, 0))) 2623 return SDValue(N, 0); 2624 2625 2626 // If the sign bit is known to be zero, switch this to a SRL. 2627 if (DAG.SignBitIsZero(N0)) 2628 return DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, N0, N1); 2629 2630 return N1C ? visitShiftByConstant(N, N1C->getZExtValue()) : SDValue(); 2631} 2632 2633SDValue DAGCombiner::visitSRL(SDNode *N) { 2634 SDValue N0 = N->getOperand(0); 2635 SDValue N1 = N->getOperand(1); 2636 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 2637 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 2638 EVT VT = N0.getValueType(); 2639 unsigned OpSizeInBits = VT.getSizeInBits(); 2640 2641 // fold (srl c1, c2) -> c1 >>u c2 2642 if (N0C && N1C) 2643 return DAG.FoldConstantArithmetic(ISD::SRL, VT, N0C, N1C); 2644 // fold (srl 0, x) -> 0 2645 if (N0C && N0C->isNullValue()) 2646 return N0; 2647 // fold (srl x, c >= size(x)) -> undef 2648 if (N1C && N1C->getZExtValue() >= OpSizeInBits) 2649 return DAG.getUNDEF(VT); 2650 // fold (srl x, 0) -> x 2651 if (N1C && N1C->isNullValue()) 2652 return N0; 2653 // if (srl x, c) is known to be zero, return 0 2654 if (N1C && DAG.MaskedValueIsZero(SDValue(N, 0), 2655 APInt::getAllOnesValue(OpSizeInBits))) 2656 return DAG.getConstant(0, VT); 2657 2658 // fold (srl (srl x, c1), c2) -> 0 or (srl x, (add c1, c2)) 2659 if (N1C && N0.getOpcode() == ISD::SRL && 2660 N0.getOperand(1).getOpcode() == ISD::Constant) { 2661 uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getZExtValue(); 2662 uint64_t c2 = N1C->getZExtValue(); 2663 if (c1 + c2 > OpSizeInBits) 2664 return DAG.getConstant(0, VT); 2665 return DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, N0.getOperand(0), 2666 DAG.getConstant(c1 + c2, N1.getValueType())); 2667 } 2668 2669 // fold (srl (anyextend x), c) -> (anyextend (srl x, c)) 2670 if (N1C && N0.getOpcode() == ISD::ANY_EXTEND) { 2671 // Shifting in all undef bits? 2672 EVT SmallVT = N0.getOperand(0).getValueType(); 2673 if (N1C->getZExtValue() >= SmallVT.getSizeInBits()) 2674 return DAG.getUNDEF(VT); 2675 2676 SDValue SmallShift = DAG.getNode(ISD::SRL, N0.getDebugLoc(), SmallVT, 2677 N0.getOperand(0), N1); 2678 AddToWorkList(SmallShift.getNode()); 2679 return DAG.getNode(ISD::ANY_EXTEND, N->getDebugLoc(), VT, SmallShift); 2680 } 2681 2682 // fold (srl (sra X, Y), 31) -> (srl X, 31). This srl only looks at the sign 2683 // bit, which is unmodified by sra. 2684 if (N1C && N1C->getZExtValue() + 1 == VT.getSizeInBits()) { 2685 if (N0.getOpcode() == ISD::SRA) 2686 return DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, N0.getOperand(0), N1); 2687 } 2688 2689 // fold (srl (ctlz x), "5") -> x iff x has one bit set (the low bit). 2690 if (N1C && N0.getOpcode() == ISD::CTLZ && 2691 N1C->getAPIntValue() == Log2_32(VT.getSizeInBits())) { 2692 APInt KnownZero, KnownOne; 2693 APInt Mask = APInt::getAllOnesValue(VT.getSizeInBits()); 2694 DAG.ComputeMaskedBits(N0.getOperand(0), Mask, KnownZero, KnownOne); 2695 2696 // If any of the input bits are KnownOne, then the input couldn't be all 2697 // zeros, thus the result of the srl will always be zero. 2698 if (KnownOne.getBoolValue()) return DAG.getConstant(0, VT); 2699 2700 // If all of the bits input the to ctlz node are known to be zero, then 2701 // the result of the ctlz is "32" and the result of the shift is one. 2702 APInt UnknownBits = ~KnownZero & Mask; 2703 if (UnknownBits == 0) return DAG.getConstant(1, VT); 2704 2705 // Otherwise, check to see if there is exactly one bit input to the ctlz. 2706 if ((UnknownBits & (UnknownBits - 1)) == 0) { 2707 // Okay, we know that only that the single bit specified by UnknownBits 2708 // could be set on input to the CTLZ node. If this bit is set, the SRL 2709 // will return 0, if it is clear, it returns 1. Change the CTLZ/SRL pair 2710 // to an SRL/XOR pair, which is likely to simplify more. 2711 unsigned ShAmt = UnknownBits.countTrailingZeros(); 2712 SDValue Op = N0.getOperand(0); 2713 2714 if (ShAmt) { 2715 Op = DAG.getNode(ISD::SRL, N0.getDebugLoc(), VT, Op, 2716 DAG.getConstant(ShAmt, getShiftAmountTy())); 2717 AddToWorkList(Op.getNode()); 2718 } 2719 2720 return DAG.getNode(ISD::XOR, N->getDebugLoc(), VT, 2721 Op, DAG.getConstant(1, VT)); 2722 } 2723 } 2724 2725 // fold (srl x, (trunc (and y, c))) -> (srl x, (and (trunc y), (trunc c))). 2726 if (N1.getOpcode() == ISD::TRUNCATE && 2727 N1.getOperand(0).getOpcode() == ISD::AND && 2728 N1.hasOneUse() && N1.getOperand(0).hasOneUse()) { 2729 SDValue N101 = N1.getOperand(0).getOperand(1); 2730 if (ConstantSDNode *N101C = dyn_cast<ConstantSDNode>(N101)) { 2731 EVT TruncVT = N1.getValueType(); 2732 SDValue N100 = N1.getOperand(0).getOperand(0); 2733 APInt TruncC = N101C->getAPIntValue(); 2734 TruncC.trunc(TruncVT.getSizeInBits()); 2735 return DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, N0, 2736 DAG.getNode(ISD::AND, N->getDebugLoc(), 2737 TruncVT, 2738 DAG.getNode(ISD::TRUNCATE, 2739 N->getDebugLoc(), 2740 TruncVT, N100), 2741 DAG.getConstant(TruncC, TruncVT))); 2742 } 2743 } 2744 2745 // fold operands of srl based on knowledge that the low bits are not 2746 // demanded. 2747 if (N1C && SimplifyDemandedBits(SDValue(N, 0))) 2748 return SDValue(N, 0); 2749 2750 return N1C ? visitShiftByConstant(N, N1C->getZExtValue()) : SDValue(); 2751} 2752 2753SDValue DAGCombiner::visitCTLZ(SDNode *N) { 2754 SDValue N0 = N->getOperand(0); 2755 EVT VT = N->getValueType(0); 2756 2757 // fold (ctlz c1) -> c2 2758 if (isa<ConstantSDNode>(N0)) 2759 return DAG.getNode(ISD::CTLZ, N->getDebugLoc(), VT, N0); 2760 return SDValue(); 2761} 2762 2763SDValue DAGCombiner::visitCTTZ(SDNode *N) { 2764 SDValue N0 = N->getOperand(0); 2765 EVT VT = N->getValueType(0); 2766 2767 // fold (cttz c1) -> c2 2768 if (isa<ConstantSDNode>(N0)) 2769 return DAG.getNode(ISD::CTTZ, N->getDebugLoc(), VT, N0); 2770 return SDValue(); 2771} 2772 2773SDValue DAGCombiner::visitCTPOP(SDNode *N) { 2774 SDValue N0 = N->getOperand(0); 2775 EVT VT = N->getValueType(0); 2776 2777 // fold (ctpop c1) -> c2 2778 if (isa<ConstantSDNode>(N0)) 2779 return DAG.getNode(ISD::CTPOP, N->getDebugLoc(), VT, N0); 2780 return SDValue(); 2781} 2782 2783SDValue DAGCombiner::visitSELECT(SDNode *N) { 2784 SDValue N0 = N->getOperand(0); 2785 SDValue N1 = N->getOperand(1); 2786 SDValue N2 = N->getOperand(2); 2787 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 2788 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 2789 ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(N2); 2790 EVT VT = N->getValueType(0); 2791 EVT VT0 = N0.getValueType(); 2792 2793 // fold (select C, X, X) -> X 2794 if (N1 == N2) 2795 return N1; 2796 // fold (select true, X, Y) -> X 2797 if (N0C && !N0C->isNullValue()) 2798 return N1; 2799 // fold (select false, X, Y) -> Y 2800 if (N0C && N0C->isNullValue()) 2801 return N2; 2802 // fold (select C, 1, X) -> (or C, X) 2803 if (VT == MVT::i1 && N1C && N1C->getAPIntValue() == 1) 2804 return DAG.getNode(ISD::OR, N->getDebugLoc(), VT, N0, N2); 2805 // fold (select C, 0, 1) -> (xor C, 1) 2806 if (VT.isInteger() && 2807 (VT0 == MVT::i1 || 2808 (VT0.isInteger() && 2809 TLI.getBooleanContents() == TargetLowering::ZeroOrOneBooleanContent)) && 2810 N1C && N2C && N1C->isNullValue() && N2C->getAPIntValue() == 1) { 2811 SDValue XORNode; 2812 if (VT == VT0) 2813 return DAG.getNode(ISD::XOR, N->getDebugLoc(), VT0, 2814 N0, DAG.getConstant(1, VT0)); 2815 XORNode = DAG.getNode(ISD::XOR, N0.getDebugLoc(), VT0, 2816 N0, DAG.getConstant(1, VT0)); 2817 AddToWorkList(XORNode.getNode()); 2818 if (VT.bitsGT(VT0)) 2819 return DAG.getNode(ISD::ZERO_EXTEND, N->getDebugLoc(), VT, XORNode); 2820 return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, XORNode); 2821 } 2822 // fold (select C, 0, X) -> (and (not C), X) 2823 if (VT == VT0 && VT == MVT::i1 && N1C && N1C->isNullValue()) { 2824 SDValue NOTNode = DAG.getNOT(N0.getDebugLoc(), N0, VT); 2825 AddToWorkList(NOTNode.getNode()); 2826 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, NOTNode, N2); 2827 } 2828 // fold (select C, X, 1) -> (or (not C), X) 2829 if (VT == VT0 && VT == MVT::i1 && N2C && N2C->getAPIntValue() == 1) { 2830 SDValue NOTNode = DAG.getNOT(N0.getDebugLoc(), N0, VT); 2831 AddToWorkList(NOTNode.getNode()); 2832 return DAG.getNode(ISD::OR, N->getDebugLoc(), VT, NOTNode, N1); 2833 } 2834 // fold (select C, X, 0) -> (and C, X) 2835 if (VT == MVT::i1 && N2C && N2C->isNullValue()) 2836 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, N0, N1); 2837 // fold (select X, X, Y) -> (or X, Y) 2838 // fold (select X, 1, Y) -> (or X, Y) 2839 if (VT == MVT::i1 && (N0 == N1 || (N1C && N1C->getAPIntValue() == 1))) 2840 return DAG.getNode(ISD::OR, N->getDebugLoc(), VT, N0, N2); 2841 // fold (select X, Y, X) -> (and X, Y) 2842 // fold (select X, Y, 0) -> (and X, Y) 2843 if (VT == MVT::i1 && (N0 == N2 || (N2C && N2C->getAPIntValue() == 0))) 2844 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, N0, N1); 2845 2846 // If we can fold this based on the true/false value, do so. 2847 if (SimplifySelectOps(N, N1, N2)) 2848 return SDValue(N, 0); // Don't revisit N. 2849 2850 // fold selects based on a setcc into other things, such as min/max/abs 2851 if (N0.getOpcode() == ISD::SETCC) { 2852 // FIXME: 2853 // Check against MVT::Other for SELECT_CC, which is a workaround for targets 2854 // having to say they don't support SELECT_CC on every type the DAG knows 2855 // about, since there is no way to mark an opcode illegal at all value types 2856 if (TLI.isOperationLegalOrCustom(ISD::SELECT_CC, MVT::Other) && 2857 TLI.isOperationLegalOrCustom(ISD::SELECT_CC, VT)) 2858 return DAG.getNode(ISD::SELECT_CC, N->getDebugLoc(), VT, 2859 N0.getOperand(0), N0.getOperand(1), 2860 N1, N2, N0.getOperand(2)); 2861 return SimplifySelect(N->getDebugLoc(), N0, N1, N2); 2862 } 2863 2864 return SDValue(); 2865} 2866 2867SDValue DAGCombiner::visitSELECT_CC(SDNode *N) { 2868 SDValue N0 = N->getOperand(0); 2869 SDValue N1 = N->getOperand(1); 2870 SDValue N2 = N->getOperand(2); 2871 SDValue N3 = N->getOperand(3); 2872 SDValue N4 = N->getOperand(4); 2873 ISD::CondCode CC = cast<CondCodeSDNode>(N4)->get(); 2874 2875 // fold select_cc lhs, rhs, x, x, cc -> x 2876 if (N2 == N3) 2877 return N2; 2878 2879 // Determine if the condition we're dealing with is constant 2880 SDValue SCC = SimplifySetCC(TLI.getSetCCResultType(N0.getValueType()), 2881 N0, N1, CC, N->getDebugLoc(), false); 2882 if (SCC.getNode()) AddToWorkList(SCC.getNode()); 2883 2884 if (ConstantSDNode *SCCC = dyn_cast_or_null<ConstantSDNode>(SCC.getNode())) { 2885 if (!SCCC->isNullValue()) 2886 return N2; // cond always true -> true val 2887 else 2888 return N3; // cond always false -> false val 2889 } 2890 2891 // Fold to a simpler select_cc 2892 if (SCC.getNode() && SCC.getOpcode() == ISD::SETCC) 2893 return DAG.getNode(ISD::SELECT_CC, N->getDebugLoc(), N2.getValueType(), 2894 SCC.getOperand(0), SCC.getOperand(1), N2, N3, 2895 SCC.getOperand(2)); 2896 2897 // If we can fold this based on the true/false value, do so. 2898 if (SimplifySelectOps(N, N2, N3)) 2899 return SDValue(N, 0); // Don't revisit N. 2900 2901 // fold select_cc into other things, such as min/max/abs 2902 return SimplifySelectCC(N->getDebugLoc(), N0, N1, N2, N3, CC); 2903} 2904 2905SDValue DAGCombiner::visitSETCC(SDNode *N) { 2906 return SimplifySetCC(N->getValueType(0), N->getOperand(0), N->getOperand(1), 2907 cast<CondCodeSDNode>(N->getOperand(2))->get(), 2908 N->getDebugLoc()); 2909} 2910 2911// ExtendUsesToFormExtLoad - Trying to extend uses of a load to enable this: 2912// "fold ({s|z|a}ext (load x)) -> ({s|z|a}ext (truncate ({s|z|a}extload x)))" 2913// transformation. Returns true if extension are possible and the above 2914// mentioned transformation is profitable. 2915static bool ExtendUsesToFormExtLoad(SDNode *N, SDValue N0, 2916 unsigned ExtOpc, 2917 SmallVector<SDNode*, 4> &ExtendNodes, 2918 const TargetLowering &TLI) { 2919 bool HasCopyToRegUses = false; 2920 bool isTruncFree = TLI.isTruncateFree(N->getValueType(0), N0.getValueType()); 2921 for (SDNode::use_iterator UI = N0.getNode()->use_begin(), 2922 UE = N0.getNode()->use_end(); 2923 UI != UE; ++UI) { 2924 SDNode *User = *UI; 2925 if (User == N) 2926 continue; 2927 if (UI.getUse().getResNo() != N0.getResNo()) 2928 continue; 2929 // FIXME: Only extend SETCC N, N and SETCC N, c for now. 2930 if (ExtOpc != ISD::ANY_EXTEND && User->getOpcode() == ISD::SETCC) { 2931 ISD::CondCode CC = cast<CondCodeSDNode>(User->getOperand(2))->get(); 2932 if (ExtOpc == ISD::ZERO_EXTEND && ISD::isSignedIntSetCC(CC)) 2933 // Sign bits will be lost after a zext. 2934 return false; 2935 bool Add = false; 2936 for (unsigned i = 0; i != 2; ++i) { 2937 SDValue UseOp = User->getOperand(i); 2938 if (UseOp == N0) 2939 continue; 2940 if (!isa<ConstantSDNode>(UseOp)) 2941 return false; 2942 Add = true; 2943 } 2944 if (Add) 2945 ExtendNodes.push_back(User); 2946 continue; 2947 } 2948 // If truncates aren't free and there are users we can't 2949 // extend, it isn't worthwhile. 2950 if (!isTruncFree) 2951 return false; 2952 // Remember if this value is live-out. 2953 if (User->getOpcode() == ISD::CopyToReg) 2954 HasCopyToRegUses = true; 2955 } 2956 2957 if (HasCopyToRegUses) { 2958 bool BothLiveOut = false; 2959 for (SDNode::use_iterator UI = N->use_begin(), UE = N->use_end(); 2960 UI != UE; ++UI) { 2961 SDUse &Use = UI.getUse(); 2962 if (Use.getResNo() == 0 && Use.getUser()->getOpcode() == ISD::CopyToReg) { 2963 BothLiveOut = true; 2964 break; 2965 } 2966 } 2967 if (BothLiveOut) 2968 // Both unextended and extended values are live out. There had better be 2969 // good a reason for the transformation. 2970 return ExtendNodes.size(); 2971 } 2972 return true; 2973} 2974 2975SDValue DAGCombiner::visitSIGN_EXTEND(SDNode *N) { 2976 SDValue N0 = N->getOperand(0); 2977 EVT VT = N->getValueType(0); 2978 2979 // fold (sext c1) -> c1 2980 if (isa<ConstantSDNode>(N0)) 2981 return DAG.getNode(ISD::SIGN_EXTEND, N->getDebugLoc(), VT, N0); 2982 2983 // fold (sext (sext x)) -> (sext x) 2984 // fold (sext (aext x)) -> (sext x) 2985 if (N0.getOpcode() == ISD::SIGN_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND) 2986 return DAG.getNode(ISD::SIGN_EXTEND, N->getDebugLoc(), VT, 2987 N0.getOperand(0)); 2988 2989 if (N0.getOpcode() == ISD::TRUNCATE) { 2990 // fold (sext (truncate (load x))) -> (sext (smaller load x)) 2991 // fold (sext (truncate (srl (load x), c))) -> (sext (smaller load (x+c/n))) 2992 SDValue NarrowLoad = ReduceLoadWidth(N0.getNode()); 2993 if (NarrowLoad.getNode()) { 2994 if (NarrowLoad.getNode() != N0.getNode()) 2995 CombineTo(N0.getNode(), NarrowLoad); 2996 return SDValue(N, 0); // Return N so it doesn't get rechecked! 2997 } 2998 2999 // See if the value being truncated is already sign extended. If so, just 3000 // eliminate the trunc/sext pair. 3001 SDValue Op = N0.getOperand(0); 3002 unsigned OpBits = Op.getValueType().getSizeInBits(); 3003 unsigned MidBits = N0.getValueType().getSizeInBits(); 3004 unsigned DestBits = VT.getSizeInBits(); 3005 unsigned NumSignBits = DAG.ComputeNumSignBits(Op); 3006 3007 if (OpBits == DestBits) { 3008 // Op is i32, Mid is i8, and Dest is i32. If Op has more than 24 sign 3009 // bits, it is already ready. 3010 if (NumSignBits > DestBits-MidBits) 3011 return Op; 3012 } else if (OpBits < DestBits) { 3013 // Op is i32, Mid is i8, and Dest is i64. If Op has more than 24 sign 3014 // bits, just sext from i32. 3015 if (NumSignBits > OpBits-MidBits) 3016 return DAG.getNode(ISD::SIGN_EXTEND, N->getDebugLoc(), VT, Op); 3017 } else { 3018 // Op is i64, Mid is i8, and Dest is i32. If Op has more than 56 sign 3019 // bits, just truncate to i32. 3020 if (NumSignBits > OpBits-MidBits) 3021 return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, Op); 3022 } 3023 3024 // fold (sext (truncate x)) -> (sextinreg x). 3025 if (!LegalOperations || TLI.isOperationLegal(ISD::SIGN_EXTEND_INREG, 3026 N0.getValueType())) { 3027 if (Op.getValueType().bitsLT(VT)) 3028 Op = DAG.getNode(ISD::ANY_EXTEND, N0.getDebugLoc(), VT, Op); 3029 else if (Op.getValueType().bitsGT(VT)) 3030 Op = DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(), VT, Op); 3031 return DAG.getNode(ISD::SIGN_EXTEND_INREG, N->getDebugLoc(), VT, Op, 3032 DAG.getValueType(N0.getValueType())); 3033 } 3034 } 3035 3036 // fold (sext (load x)) -> (sext (truncate (sextload x))) 3037 if (ISD::isNON_EXTLoad(N0.getNode()) && 3038 ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) || 3039 TLI.isLoadExtLegal(ISD::SEXTLOAD, N0.getValueType()))) { 3040 bool DoXform = true; 3041 SmallVector<SDNode*, 4> SetCCs; 3042 if (!N0.hasOneUse()) 3043 DoXform = ExtendUsesToFormExtLoad(N, N0, ISD::SIGN_EXTEND, SetCCs, TLI); 3044 if (DoXform) { 3045 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 3046 SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, N->getDebugLoc(), VT, 3047 LN0->getChain(), 3048 LN0->getBasePtr(), LN0->getSrcValue(), 3049 LN0->getSrcValueOffset(), 3050 N0.getValueType(), 3051 LN0->isVolatile(), LN0->getAlignment()); 3052 CombineTo(N, ExtLoad); 3053 SDValue Trunc = DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(), 3054 N0.getValueType(), ExtLoad); 3055 CombineTo(N0.getNode(), Trunc, ExtLoad.getValue(1)); 3056 3057 // Extend SetCC uses if necessary. 3058 for (unsigned i = 0, e = SetCCs.size(); i != e; ++i) { 3059 SDNode *SetCC = SetCCs[i]; 3060 SmallVector<SDValue, 4> Ops; 3061 3062 for (unsigned j = 0; j != 2; ++j) { 3063 SDValue SOp = SetCC->getOperand(j); 3064 if (SOp == Trunc) 3065 Ops.push_back(ExtLoad); 3066 else 3067 Ops.push_back(DAG.getNode(ISD::SIGN_EXTEND, 3068 N->getDebugLoc(), VT, SOp)); 3069 } 3070 3071 Ops.push_back(SetCC->getOperand(2)); 3072 CombineTo(SetCC, DAG.getNode(ISD::SETCC, N->getDebugLoc(), 3073 SetCC->getValueType(0), 3074 &Ops[0], Ops.size())); 3075 } 3076 3077 return SDValue(N, 0); // Return N so it doesn't get rechecked! 3078 } 3079 } 3080 3081 // fold (sext (sextload x)) -> (sext (truncate (sextload x))) 3082 // fold (sext ( extload x)) -> (sext (truncate (sextload x))) 3083 if ((ISD::isSEXTLoad(N0.getNode()) || ISD::isEXTLoad(N0.getNode())) && 3084 ISD::isUNINDEXEDLoad(N0.getNode()) && N0.hasOneUse()) { 3085 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 3086 EVT MemVT = LN0->getMemoryVT(); 3087 if ((!LegalOperations && !LN0->isVolatile()) || 3088 TLI.isLoadExtLegal(ISD::SEXTLOAD, MemVT)) { 3089 SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, N->getDebugLoc(), VT, 3090 LN0->getChain(), 3091 LN0->getBasePtr(), LN0->getSrcValue(), 3092 LN0->getSrcValueOffset(), MemVT, 3093 LN0->isVolatile(), LN0->getAlignment()); 3094 CombineTo(N, ExtLoad); 3095 CombineTo(N0.getNode(), 3096 DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(), 3097 N0.getValueType(), ExtLoad), 3098 ExtLoad.getValue(1)); 3099 return SDValue(N, 0); // Return N so it doesn't get rechecked! 3100 } 3101 } 3102 3103 if (N0.getOpcode() == ISD::SETCC) { 3104 // sext(setcc) -> sext_in_reg(vsetcc) for vectors. 3105 if (VT.isVector() && 3106 // We know that the # elements of the results is the same as the 3107 // # elements of the compare (and the # elements of the compare result 3108 // for that matter). Check to see that they are the same size. If so, 3109 // we know that the element size of the sext'd result matches the 3110 // element size of the compare operands. 3111 VT.getSizeInBits() == N0.getOperand(0).getValueType().getSizeInBits() && 3112 3113 // Only do this before legalize for now. 3114 !LegalOperations) { 3115 return DAG.getVSetCC(N->getDebugLoc(), VT, N0.getOperand(0), 3116 N0.getOperand(1), 3117 cast<CondCodeSDNode>(N0.getOperand(2))->get()); 3118 } 3119 3120 // sext(setcc x, y, cc) -> (select_cc x, y, -1, 0, cc) 3121 SDValue NegOne = 3122 DAG.getConstant(APInt::getAllOnesValue(VT.getSizeInBits()), VT); 3123 SDValue SCC = 3124 SimplifySelectCC(N->getDebugLoc(), N0.getOperand(0), N0.getOperand(1), 3125 NegOne, DAG.getConstant(0, VT), 3126 cast<CondCodeSDNode>(N0.getOperand(2))->get(), true); 3127 if (SCC.getNode()) return SCC; 3128 } 3129 3130 3131 3132 // fold (sext x) -> (zext x) if the sign bit is known zero. 3133 if ((!LegalOperations || TLI.isOperationLegal(ISD::ZERO_EXTEND, VT)) && 3134 DAG.SignBitIsZero(N0)) 3135 return DAG.getNode(ISD::ZERO_EXTEND, N->getDebugLoc(), VT, N0); 3136 3137 return SDValue(); 3138} 3139 3140SDValue DAGCombiner::visitZERO_EXTEND(SDNode *N) { 3141 SDValue N0 = N->getOperand(0); 3142 EVT VT = N->getValueType(0); 3143 3144 // fold (zext c1) -> c1 3145 if (isa<ConstantSDNode>(N0)) 3146 return DAG.getNode(ISD::ZERO_EXTEND, N->getDebugLoc(), VT, N0); 3147 // fold (zext (zext x)) -> (zext x) 3148 // fold (zext (aext x)) -> (zext x) 3149 if (N0.getOpcode() == ISD::ZERO_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND) 3150 return DAG.getNode(ISD::ZERO_EXTEND, N->getDebugLoc(), VT, 3151 N0.getOperand(0)); 3152 3153 // fold (zext (truncate (load x))) -> (zext (smaller load x)) 3154 // fold (zext (truncate (srl (load x), c))) -> (zext (small load (x+c/n))) 3155 if (N0.getOpcode() == ISD::TRUNCATE) { 3156 SDValue NarrowLoad = ReduceLoadWidth(N0.getNode()); 3157 if (NarrowLoad.getNode()) { 3158 if (NarrowLoad.getNode() != N0.getNode()) 3159 CombineTo(N0.getNode(), NarrowLoad); 3160 return DAG.getNode(ISD::ZERO_EXTEND, N->getDebugLoc(), VT, NarrowLoad); 3161 } 3162 } 3163 3164 // fold (zext (truncate x)) -> (and x, mask) 3165 if (N0.getOpcode() == ISD::TRUNCATE && 3166 (!LegalOperations || TLI.isOperationLegal(ISD::AND, VT))) { 3167 SDValue Op = N0.getOperand(0); 3168 if (Op.getValueType().bitsLT(VT)) { 3169 Op = DAG.getNode(ISD::ANY_EXTEND, N->getDebugLoc(), VT, Op); 3170 } else if (Op.getValueType().bitsGT(VT)) { 3171 Op = DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, Op); 3172 } 3173 return DAG.getZeroExtendInReg(Op, N->getDebugLoc(), N0.getValueType()); 3174 } 3175 3176 // Fold (zext (and (trunc x), cst)) -> (and x, cst), 3177 // if either of the casts is not free. 3178 if (N0.getOpcode() == ISD::AND && 3179 N0.getOperand(0).getOpcode() == ISD::TRUNCATE && 3180 N0.getOperand(1).getOpcode() == ISD::Constant && 3181 (!TLI.isTruncateFree(N0.getOperand(0).getOperand(0).getValueType(), 3182 N0.getValueType()) || 3183 !TLI.isZExtFree(N0.getValueType(), VT))) { 3184 SDValue X = N0.getOperand(0).getOperand(0); 3185 if (X.getValueType().bitsLT(VT)) { 3186 X = DAG.getNode(ISD::ANY_EXTEND, X.getDebugLoc(), VT, X); 3187 } else if (X.getValueType().bitsGT(VT)) { 3188 X = DAG.getNode(ISD::TRUNCATE, X.getDebugLoc(), VT, X); 3189 } 3190 APInt Mask = cast<ConstantSDNode>(N0.getOperand(1))->getAPIntValue(); 3191 Mask.zext(VT.getSizeInBits()); 3192 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, 3193 X, DAG.getConstant(Mask, VT)); 3194 } 3195 3196 // fold (zext (load x)) -> (zext (truncate (zextload x))) 3197 if (ISD::isNON_EXTLoad(N0.getNode()) && 3198 ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) || 3199 TLI.isLoadExtLegal(ISD::ZEXTLOAD, N0.getValueType()))) { 3200 bool DoXform = true; 3201 SmallVector<SDNode*, 4> SetCCs; 3202 if (!N0.hasOneUse()) 3203 DoXform = ExtendUsesToFormExtLoad(N, N0, ISD::ZERO_EXTEND, SetCCs, TLI); 3204 if (DoXform) { 3205 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 3206 SDValue ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, N->getDebugLoc(), VT, 3207 LN0->getChain(), 3208 LN0->getBasePtr(), LN0->getSrcValue(), 3209 LN0->getSrcValueOffset(), 3210 N0.getValueType(), 3211 LN0->isVolatile(), LN0->getAlignment()); 3212 CombineTo(N, ExtLoad); 3213 SDValue Trunc = DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(), 3214 N0.getValueType(), ExtLoad); 3215 CombineTo(N0.getNode(), Trunc, ExtLoad.getValue(1)); 3216 3217 // Extend SetCC uses if necessary. 3218 for (unsigned i = 0, e = SetCCs.size(); i != e; ++i) { 3219 SDNode *SetCC = SetCCs[i]; 3220 SmallVector<SDValue, 4> Ops; 3221 3222 for (unsigned j = 0; j != 2; ++j) { 3223 SDValue SOp = SetCC->getOperand(j); 3224 if (SOp == Trunc) 3225 Ops.push_back(ExtLoad); 3226 else 3227 Ops.push_back(DAG.getNode(ISD::ZERO_EXTEND, 3228 N->getDebugLoc(), VT, SOp)); 3229 } 3230 3231 Ops.push_back(SetCC->getOperand(2)); 3232 CombineTo(SetCC, DAG.getNode(ISD::SETCC, N->getDebugLoc(), 3233 SetCC->getValueType(0), 3234 &Ops[0], Ops.size())); 3235 } 3236 3237 return SDValue(N, 0); // Return N so it doesn't get rechecked! 3238 } 3239 } 3240 3241 // fold (zext (zextload x)) -> (zext (truncate (zextload x))) 3242 // fold (zext ( extload x)) -> (zext (truncate (zextload x))) 3243 if ((ISD::isZEXTLoad(N0.getNode()) || ISD::isEXTLoad(N0.getNode())) && 3244 ISD::isUNINDEXEDLoad(N0.getNode()) && N0.hasOneUse()) { 3245 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 3246 EVT MemVT = LN0->getMemoryVT(); 3247 if ((!LegalOperations && !LN0->isVolatile()) || 3248 TLI.isLoadExtLegal(ISD::ZEXTLOAD, MemVT)) { 3249 SDValue ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, N->getDebugLoc(), VT, 3250 LN0->getChain(), 3251 LN0->getBasePtr(), LN0->getSrcValue(), 3252 LN0->getSrcValueOffset(), MemVT, 3253 LN0->isVolatile(), LN0->getAlignment()); 3254 CombineTo(N, ExtLoad); 3255 CombineTo(N0.getNode(), 3256 DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(), N0.getValueType(), 3257 ExtLoad), 3258 ExtLoad.getValue(1)); 3259 return SDValue(N, 0); // Return N so it doesn't get rechecked! 3260 } 3261 } 3262 3263 // zext(setcc x,y,cc) -> select_cc x, y, 1, 0, cc 3264 if (N0.getOpcode() == ISD::SETCC) { 3265 SDValue SCC = 3266 SimplifySelectCC(N->getDebugLoc(), N0.getOperand(0), N0.getOperand(1), 3267 DAG.getConstant(1, VT), DAG.getConstant(0, VT), 3268 cast<CondCodeSDNode>(N0.getOperand(2))->get(), true); 3269 if (SCC.getNode()) return SCC; 3270 } 3271 3272 return SDValue(); 3273} 3274 3275SDValue DAGCombiner::visitANY_EXTEND(SDNode *N) { 3276 SDValue N0 = N->getOperand(0); 3277 EVT VT = N->getValueType(0); 3278 3279 // fold (aext c1) -> c1 3280 if (isa<ConstantSDNode>(N0)) 3281 return DAG.getNode(ISD::ANY_EXTEND, N->getDebugLoc(), VT, N0); 3282 // fold (aext (aext x)) -> (aext x) 3283 // fold (aext (zext x)) -> (zext x) 3284 // fold (aext (sext x)) -> (sext x) 3285 if (N0.getOpcode() == ISD::ANY_EXTEND || 3286 N0.getOpcode() == ISD::ZERO_EXTEND || 3287 N0.getOpcode() == ISD::SIGN_EXTEND) 3288 return DAG.getNode(N0.getOpcode(), N->getDebugLoc(), VT, N0.getOperand(0)); 3289 3290 // fold (aext (truncate (load x))) -> (aext (smaller load x)) 3291 // fold (aext (truncate (srl (load x), c))) -> (aext (small load (x+c/n))) 3292 if (N0.getOpcode() == ISD::TRUNCATE) { 3293 SDValue NarrowLoad = ReduceLoadWidth(N0.getNode()); 3294 if (NarrowLoad.getNode()) { 3295 if (NarrowLoad.getNode() != N0.getNode()) 3296 CombineTo(N0.getNode(), NarrowLoad); 3297 return DAG.getNode(ISD::ANY_EXTEND, N->getDebugLoc(), VT, NarrowLoad); 3298 } 3299 } 3300 3301 // fold (aext (truncate x)) 3302 if (N0.getOpcode() == ISD::TRUNCATE) { 3303 SDValue TruncOp = N0.getOperand(0); 3304 if (TruncOp.getValueType() == VT) 3305 return TruncOp; // x iff x size == zext size. 3306 if (TruncOp.getValueType().bitsGT(VT)) 3307 return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, TruncOp); 3308 return DAG.getNode(ISD::ANY_EXTEND, N->getDebugLoc(), VT, TruncOp); 3309 } 3310 3311 // Fold (aext (and (trunc x), cst)) -> (and x, cst) 3312 // if the trunc is not free. 3313 if (N0.getOpcode() == ISD::AND && 3314 N0.getOperand(0).getOpcode() == ISD::TRUNCATE && 3315 N0.getOperand(1).getOpcode() == ISD::Constant && 3316 !TLI.isTruncateFree(N0.getOperand(0).getOperand(0).getValueType(), 3317 N0.getValueType())) { 3318 SDValue X = N0.getOperand(0).getOperand(0); 3319 if (X.getValueType().bitsLT(VT)) { 3320 X = DAG.getNode(ISD::ANY_EXTEND, N->getDebugLoc(), VT, X); 3321 } else if (X.getValueType().bitsGT(VT)) { 3322 X = DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, X); 3323 } 3324 APInt Mask = cast<ConstantSDNode>(N0.getOperand(1))->getAPIntValue(); 3325 Mask.zext(VT.getSizeInBits()); 3326 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, 3327 X, DAG.getConstant(Mask, VT)); 3328 } 3329 3330 // fold (aext (load x)) -> (aext (truncate (extload x))) 3331 if (ISD::isNON_EXTLoad(N0.getNode()) && 3332 ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) || 3333 TLI.isLoadExtLegal(ISD::EXTLOAD, N0.getValueType()))) { 3334 bool DoXform = true; 3335 SmallVector<SDNode*, 4> SetCCs; 3336 if (!N0.hasOneUse()) 3337 DoXform = ExtendUsesToFormExtLoad(N, N0, ISD::ANY_EXTEND, SetCCs, TLI); 3338 if (DoXform) { 3339 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 3340 SDValue ExtLoad = DAG.getExtLoad(ISD::EXTLOAD, N->getDebugLoc(), VT, 3341 LN0->getChain(), 3342 LN0->getBasePtr(), LN0->getSrcValue(), 3343 LN0->getSrcValueOffset(), 3344 N0.getValueType(), 3345 LN0->isVolatile(), LN0->getAlignment()); 3346 CombineTo(N, ExtLoad); 3347 SDValue Trunc = DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(), 3348 N0.getValueType(), ExtLoad); 3349 CombineTo(N0.getNode(), Trunc, ExtLoad.getValue(1)); 3350 3351 // Extend SetCC uses if necessary. 3352 for (unsigned i = 0, e = SetCCs.size(); i != e; ++i) { 3353 SDNode *SetCC = SetCCs[i]; 3354 SmallVector<SDValue, 4> Ops; 3355 3356 for (unsigned j = 0; j != 2; ++j) { 3357 SDValue SOp = SetCC->getOperand(j); 3358 if (SOp == Trunc) 3359 Ops.push_back(ExtLoad); 3360 else 3361 Ops.push_back(DAG.getNode(ISD::ANY_EXTEND, 3362 N->getDebugLoc(), VT, SOp)); 3363 } 3364 3365 Ops.push_back(SetCC->getOperand(2)); 3366 CombineTo(SetCC, DAG.getNode(ISD::SETCC, N->getDebugLoc(), 3367 SetCC->getValueType(0), 3368 &Ops[0], Ops.size())); 3369 } 3370 3371 return SDValue(N, 0); // Return N so it doesn't get rechecked! 3372 } 3373 } 3374 3375 // fold (aext (zextload x)) -> (aext (truncate (zextload x))) 3376 // fold (aext (sextload x)) -> (aext (truncate (sextload x))) 3377 // fold (aext ( extload x)) -> (aext (truncate (extload x))) 3378 if (N0.getOpcode() == ISD::LOAD && 3379 !ISD::isNON_EXTLoad(N0.getNode()) && ISD::isUNINDEXEDLoad(N0.getNode()) && 3380 N0.hasOneUse()) { 3381 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 3382 EVT MemVT = LN0->getMemoryVT(); 3383 SDValue ExtLoad = DAG.getExtLoad(LN0->getExtensionType(), N->getDebugLoc(), 3384 VT, LN0->getChain(), LN0->getBasePtr(), 3385 LN0->getSrcValue(), 3386 LN0->getSrcValueOffset(), MemVT, 3387 LN0->isVolatile(), LN0->getAlignment()); 3388 CombineTo(N, ExtLoad); 3389 CombineTo(N0.getNode(), 3390 DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(), 3391 N0.getValueType(), ExtLoad), 3392 ExtLoad.getValue(1)); 3393 return SDValue(N, 0); // Return N so it doesn't get rechecked! 3394 } 3395 3396 // aext(setcc x,y,cc) -> select_cc x, y, 1, 0, cc 3397 if (N0.getOpcode() == ISD::SETCC) { 3398 SDValue SCC = 3399 SimplifySelectCC(N->getDebugLoc(), N0.getOperand(0), N0.getOperand(1), 3400 DAG.getConstant(1, VT), DAG.getConstant(0, VT), 3401 cast<CondCodeSDNode>(N0.getOperand(2))->get(), true); 3402 if (SCC.getNode()) 3403 return SCC; 3404 } 3405 3406 return SDValue(); 3407} 3408 3409/// GetDemandedBits - See if the specified operand can be simplified with the 3410/// knowledge that only the bits specified by Mask are used. If so, return the 3411/// simpler operand, otherwise return a null SDValue. 3412SDValue DAGCombiner::GetDemandedBits(SDValue V, const APInt &Mask) { 3413 switch (V.getOpcode()) { 3414 default: break; 3415 case ISD::OR: 3416 case ISD::XOR: 3417 // If the LHS or RHS don't contribute bits to the or, drop them. 3418 if (DAG.MaskedValueIsZero(V.getOperand(0), Mask)) 3419 return V.getOperand(1); 3420 if (DAG.MaskedValueIsZero(V.getOperand(1), Mask)) 3421 return V.getOperand(0); 3422 break; 3423 case ISD::SRL: 3424 // Only look at single-use SRLs. 3425 if (!V.getNode()->hasOneUse()) 3426 break; 3427 if (ConstantSDNode *RHSC = dyn_cast<ConstantSDNode>(V.getOperand(1))) { 3428 // See if we can recursively simplify the LHS. 3429 unsigned Amt = RHSC->getZExtValue(); 3430 3431 // Watch out for shift count overflow though. 3432 if (Amt >= Mask.getBitWidth()) break; 3433 APInt NewMask = Mask << Amt; 3434 SDValue SimplifyLHS = GetDemandedBits(V.getOperand(0), NewMask); 3435 if (SimplifyLHS.getNode()) 3436 return DAG.getNode(ISD::SRL, V.getDebugLoc(), V.getValueType(), 3437 SimplifyLHS, V.getOperand(1)); 3438 } 3439 } 3440 return SDValue(); 3441} 3442 3443/// ReduceLoadWidth - If the result of a wider load is shifted to right of N 3444/// bits and then truncated to a narrower type and where N is a multiple 3445/// of number of bits of the narrower type, transform it to a narrower load 3446/// from address + N / num of bits of new type. If the result is to be 3447/// extended, also fold the extension to form a extending load. 3448SDValue DAGCombiner::ReduceLoadWidth(SDNode *N) { 3449 unsigned Opc = N->getOpcode(); 3450 ISD::LoadExtType ExtType = ISD::NON_EXTLOAD; 3451 SDValue N0 = N->getOperand(0); 3452 EVT VT = N->getValueType(0); 3453 EVT ExtVT = VT; 3454 3455 // This transformation isn't valid for vector loads. 3456 if (VT.isVector()) 3457 return SDValue(); 3458 3459 // Special case: SIGN_EXTEND_INREG is basically truncating to EVT then 3460 // extended to VT. 3461 if (Opc == ISD::SIGN_EXTEND_INREG) { 3462 ExtType = ISD::SEXTLOAD; 3463 ExtVT = cast<VTSDNode>(N->getOperand(1))->getVT(); 3464 if (LegalOperations && !TLI.isLoadExtLegal(ISD::SEXTLOAD, ExtVT)) 3465 return SDValue(); 3466 } 3467 3468 unsigned EVTBits = ExtVT.getSizeInBits(); 3469 unsigned ShAmt = 0; 3470 if (N0.getOpcode() == ISD::SRL && N0.hasOneUse() && ExtVT.isRound()) { 3471 if (ConstantSDNode *N01 = dyn_cast<ConstantSDNode>(N0.getOperand(1))) { 3472 ShAmt = N01->getZExtValue(); 3473 // Is the shift amount a multiple of size of VT? 3474 if ((ShAmt & (EVTBits-1)) == 0) { 3475 N0 = N0.getOperand(0); 3476 // Is the load width a multiple of size of VT? 3477 if ((N0.getValueType().getSizeInBits() & (EVTBits-1)) != 0) 3478 return SDValue(); 3479 } 3480 } 3481 } 3482 3483 // Do not generate loads of non-round integer types since these can 3484 // be expensive (and would be wrong if the type is not byte sized). 3485 if (isa<LoadSDNode>(N0) && N0.hasOneUse() && ExtVT.isRound() && 3486 cast<LoadSDNode>(N0)->getMemoryVT().getSizeInBits() > EVTBits && 3487 // Do not change the width of a volatile load. 3488 !cast<LoadSDNode>(N0)->isVolatile()) { 3489 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 3490 EVT PtrType = N0.getOperand(1).getValueType(); 3491 3492 // For big endian targets, we need to adjust the offset to the pointer to 3493 // load the correct bytes. 3494 if (TLI.isBigEndian()) { 3495 unsigned LVTStoreBits = LN0->getMemoryVT().getStoreSizeInBits(); 3496 unsigned EVTStoreBits = ExtVT.getStoreSizeInBits(); 3497 ShAmt = LVTStoreBits - EVTStoreBits - ShAmt; 3498 } 3499 3500 uint64_t PtrOff = ShAmt / 8; 3501 unsigned NewAlign = MinAlign(LN0->getAlignment(), PtrOff); 3502 SDValue NewPtr = DAG.getNode(ISD::ADD, LN0->getDebugLoc(), 3503 PtrType, LN0->getBasePtr(), 3504 DAG.getConstant(PtrOff, PtrType)); 3505 AddToWorkList(NewPtr.getNode()); 3506 3507 SDValue Load = (ExtType == ISD::NON_EXTLOAD) 3508 ? DAG.getLoad(VT, N0.getDebugLoc(), LN0->getChain(), NewPtr, 3509 LN0->getSrcValue(), LN0->getSrcValueOffset() + PtrOff, 3510 LN0->isVolatile(), NewAlign) 3511 : DAG.getExtLoad(ExtType, N0.getDebugLoc(), VT, LN0->getChain(), NewPtr, 3512 LN0->getSrcValue(), LN0->getSrcValueOffset() + PtrOff, 3513 ExtVT, LN0->isVolatile(), NewAlign); 3514 3515 // Replace the old load's chain with the new load's chain. 3516 WorkListRemover DeadNodes(*this); 3517 DAG.ReplaceAllUsesOfValueWith(N0.getValue(1), Load.getValue(1), 3518 &DeadNodes); 3519 3520 // Return the new loaded value. 3521 return Load; 3522 } 3523 3524 return SDValue(); 3525} 3526 3527SDValue DAGCombiner::visitSIGN_EXTEND_INREG(SDNode *N) { 3528 SDValue N0 = N->getOperand(0); 3529 SDValue N1 = N->getOperand(1); 3530 EVT VT = N->getValueType(0); 3531 EVT EVT = cast<VTSDNode>(N1)->getVT(); 3532 unsigned VTBits = VT.getSizeInBits(); 3533 unsigned EVTBits = EVT.getSizeInBits(); 3534 3535 // fold (sext_in_reg c1) -> c1 3536 if (isa<ConstantSDNode>(N0) || N0.getOpcode() == ISD::UNDEF) 3537 return DAG.getNode(ISD::SIGN_EXTEND_INREG, N->getDebugLoc(), VT, N0, N1); 3538 3539 // If the input is already sign extended, just drop the extension. 3540 if (DAG.ComputeNumSignBits(N0) >= VT.getSizeInBits()-EVTBits+1) 3541 return N0; 3542 3543 // fold (sext_in_reg (sext_in_reg x, VT2), VT1) -> (sext_in_reg x, minVT) pt2 3544 if (N0.getOpcode() == ISD::SIGN_EXTEND_INREG && 3545 EVT.bitsLT(cast<VTSDNode>(N0.getOperand(1))->getVT())) { 3546 return DAG.getNode(ISD::SIGN_EXTEND_INREG, N->getDebugLoc(), VT, 3547 N0.getOperand(0), N1); 3548 } 3549 3550 // fold (sext_in_reg (sext x)) -> (sext x) 3551 // fold (sext_in_reg (aext x)) -> (sext x) 3552 // if x is small enough. 3553 if (N0.getOpcode() == ISD::SIGN_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND) { 3554 SDValue N00 = N0.getOperand(0); 3555 if (N00.getValueType().getSizeInBits() < EVTBits) 3556 return DAG.getNode(ISD::SIGN_EXTEND, N->getDebugLoc(), VT, N00, N1); 3557 } 3558 3559 // fold (sext_in_reg x) -> (zext_in_reg x) if the sign bit is known zero. 3560 if (DAG.MaskedValueIsZero(N0, APInt::getBitsSet(VTBits, EVTBits-1, EVTBits))) 3561 return DAG.getZeroExtendInReg(N0, N->getDebugLoc(), EVT); 3562 3563 // fold operands of sext_in_reg based on knowledge that the top bits are not 3564 // demanded. 3565 if (SimplifyDemandedBits(SDValue(N, 0))) 3566 return SDValue(N, 0); 3567 3568 // fold (sext_in_reg (load x)) -> (smaller sextload x) 3569 // fold (sext_in_reg (srl (load x), c)) -> (smaller sextload (x+c/evtbits)) 3570 SDValue NarrowLoad = ReduceLoadWidth(N); 3571 if (NarrowLoad.getNode()) 3572 return NarrowLoad; 3573 3574 // fold (sext_in_reg (srl X, 24), i8) -> (sra X, 24) 3575 // fold (sext_in_reg (srl X, 23), i8) -> (sra X, 23) iff possible. 3576 // We already fold "(sext_in_reg (srl X, 25), i8) -> srl X, 25" above. 3577 if (N0.getOpcode() == ISD::SRL) { 3578 if (ConstantSDNode *ShAmt = dyn_cast<ConstantSDNode>(N0.getOperand(1))) 3579 if (ShAmt->getZExtValue()+EVTBits <= VT.getSizeInBits()) { 3580 // We can turn this into an SRA iff the input to the SRL is already sign 3581 // extended enough. 3582 unsigned InSignBits = DAG.ComputeNumSignBits(N0.getOperand(0)); 3583 if (VT.getSizeInBits()-(ShAmt->getZExtValue()+EVTBits) < InSignBits) 3584 return DAG.getNode(ISD::SRA, N->getDebugLoc(), VT, 3585 N0.getOperand(0), N0.getOperand(1)); 3586 } 3587 } 3588 3589 // fold (sext_inreg (extload x)) -> (sextload x) 3590 if (ISD::isEXTLoad(N0.getNode()) && 3591 ISD::isUNINDEXEDLoad(N0.getNode()) && 3592 EVT == cast<LoadSDNode>(N0)->getMemoryVT() && 3593 ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) || 3594 TLI.isLoadExtLegal(ISD::SEXTLOAD, EVT))) { 3595 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 3596 SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, N->getDebugLoc(), VT, 3597 LN0->getChain(), 3598 LN0->getBasePtr(), LN0->getSrcValue(), 3599 LN0->getSrcValueOffset(), EVT, 3600 LN0->isVolatile(), LN0->getAlignment()); 3601 CombineTo(N, ExtLoad); 3602 CombineTo(N0.getNode(), ExtLoad, ExtLoad.getValue(1)); 3603 return SDValue(N, 0); // Return N so it doesn't get rechecked! 3604 } 3605 // fold (sext_inreg (zextload x)) -> (sextload x) iff load has one use 3606 if (ISD::isZEXTLoad(N0.getNode()) && ISD::isUNINDEXEDLoad(N0.getNode()) && 3607 N0.hasOneUse() && 3608 EVT == cast<LoadSDNode>(N0)->getMemoryVT() && 3609 ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) || 3610 TLI.isLoadExtLegal(ISD::SEXTLOAD, EVT))) { 3611 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 3612 SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, N->getDebugLoc(), VT, 3613 LN0->getChain(), 3614 LN0->getBasePtr(), LN0->getSrcValue(), 3615 LN0->getSrcValueOffset(), EVT, 3616 LN0->isVolatile(), LN0->getAlignment()); 3617 CombineTo(N, ExtLoad); 3618 CombineTo(N0.getNode(), ExtLoad, ExtLoad.getValue(1)); 3619 return SDValue(N, 0); // Return N so it doesn't get rechecked! 3620 } 3621 return SDValue(); 3622} 3623 3624SDValue DAGCombiner::visitTRUNCATE(SDNode *N) { 3625 SDValue N0 = N->getOperand(0); 3626 EVT VT = N->getValueType(0); 3627 3628 // noop truncate 3629 if (N0.getValueType() == N->getValueType(0)) 3630 return N0; 3631 // fold (truncate c1) -> c1 3632 if (isa<ConstantSDNode>(N0)) 3633 return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, N0); 3634 // fold (truncate (truncate x)) -> (truncate x) 3635 if (N0.getOpcode() == ISD::TRUNCATE) 3636 return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, N0.getOperand(0)); 3637 // fold (truncate (ext x)) -> (ext x) or (truncate x) or x 3638 if (N0.getOpcode() == ISD::ZERO_EXTEND || N0.getOpcode() == ISD::SIGN_EXTEND|| 3639 N0.getOpcode() == ISD::ANY_EXTEND) { 3640 if (N0.getOperand(0).getValueType().bitsLT(VT)) 3641 // if the source is smaller than the dest, we still need an extend 3642 return DAG.getNode(N0.getOpcode(), N->getDebugLoc(), VT, 3643 N0.getOperand(0)); 3644 else if (N0.getOperand(0).getValueType().bitsGT(VT)) 3645 // if the source is larger than the dest, than we just need the truncate 3646 return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, N0.getOperand(0)); 3647 else 3648 // if the source and dest are the same type, we can drop both the extend 3649 // and the truncate 3650 return N0.getOperand(0); 3651 } 3652 3653 // See if we can simplify the input to this truncate through knowledge that 3654 // only the low bits are being used. For example "trunc (or (shl x, 8), y)" 3655 // -> trunc y 3656 SDValue Shorter = 3657 GetDemandedBits(N0, APInt::getLowBitsSet(N0.getValueSizeInBits(), 3658 VT.getSizeInBits())); 3659 if (Shorter.getNode()) 3660 return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, Shorter); 3661 3662 // fold (truncate (load x)) -> (smaller load x) 3663 // fold (truncate (srl (load x), c)) -> (smaller load (x+c/evtbits)) 3664 return ReduceLoadWidth(N); 3665} 3666 3667static SDNode *getBuildPairElt(SDNode *N, unsigned i) { 3668 SDValue Elt = N->getOperand(i); 3669 if (Elt.getOpcode() != ISD::MERGE_VALUES) 3670 return Elt.getNode(); 3671 return Elt.getOperand(Elt.getResNo()).getNode(); 3672} 3673 3674/// CombineConsecutiveLoads - build_pair (load, load) -> load 3675/// if load locations are consecutive. 3676SDValue DAGCombiner::CombineConsecutiveLoads(SDNode *N, EVT VT) { 3677 assert(N->getOpcode() == ISD::BUILD_PAIR); 3678 3679 LoadSDNode *LD1 = dyn_cast<LoadSDNode>(getBuildPairElt(N, 0)); 3680 LoadSDNode *LD2 = dyn_cast<LoadSDNode>(getBuildPairElt(N, 1)); 3681 if (!LD1 || !LD2 || !ISD::isNON_EXTLoad(LD1) || !LD1->hasOneUse()) 3682 return SDValue(); 3683 EVT LD1VT = LD1->getValueType(0); 3684 const MachineFrameInfo *MFI = DAG.getMachineFunction().getFrameInfo(); 3685 3686 if (ISD::isNON_EXTLoad(LD2) && 3687 LD2->hasOneUse() && 3688 // If both are volatile this would reduce the number of volatile loads. 3689 // If one is volatile it might be ok, but play conservative and bail out. 3690 !LD1->isVolatile() && 3691 !LD2->isVolatile() && 3692 TLI.isConsecutiveLoad(LD2, LD1, LD1VT.getSizeInBits()/8, 1, MFI)) { 3693 unsigned Align = LD1->getAlignment(); 3694 unsigned NewAlign = TLI.getTargetData()-> 3695 getABITypeAlignment(VT.getTypeForEVT(*DAG.getContext())); 3696 3697 if (NewAlign <= Align && 3698 (!LegalOperations || TLI.isOperationLegal(ISD::LOAD, VT))) 3699 return DAG.getLoad(VT, N->getDebugLoc(), LD1->getChain(), 3700 LD1->getBasePtr(), LD1->getSrcValue(), 3701 LD1->getSrcValueOffset(), false, Align); 3702 } 3703 3704 return SDValue(); 3705} 3706 3707SDValue DAGCombiner::visitBIT_CONVERT(SDNode *N) { 3708 SDValue N0 = N->getOperand(0); 3709 EVT VT = N->getValueType(0); 3710 3711 // If the input is a BUILD_VECTOR with all constant elements, fold this now. 3712 // Only do this before legalize, since afterward the target may be depending 3713 // on the bitconvert. 3714 // First check to see if this is all constant. 3715 if (!LegalTypes && 3716 N0.getOpcode() == ISD::BUILD_VECTOR && N0.getNode()->hasOneUse() && 3717 VT.isVector()) { 3718 bool isSimple = true; 3719 for (unsigned i = 0, e = N0.getNumOperands(); i != e; ++i) 3720 if (N0.getOperand(i).getOpcode() != ISD::UNDEF && 3721 N0.getOperand(i).getOpcode() != ISD::Constant && 3722 N0.getOperand(i).getOpcode() != ISD::ConstantFP) { 3723 isSimple = false; 3724 break; 3725 } 3726 3727 EVT DestEltVT = N->getValueType(0).getVectorElementType(); 3728 assert(!DestEltVT.isVector() && 3729 "Element type of vector ValueType must not be vector!"); 3730 if (isSimple) 3731 return ConstantFoldBIT_CONVERTofBUILD_VECTOR(N0.getNode(), DestEltVT); 3732 } 3733 3734 // If the input is a constant, let getNode fold it. 3735 if (isa<ConstantSDNode>(N0) || isa<ConstantFPSDNode>(N0)) { 3736 SDValue Res = DAG.getNode(ISD::BIT_CONVERT, N->getDebugLoc(), VT, N0); 3737 if (Res.getNode() != N) { 3738 if (!LegalOperations || 3739 TLI.isOperationLegal(Res.getNode()->getOpcode(), VT)) 3740 return Res; 3741 3742 // Folding it resulted in an illegal node, and it's too late to 3743 // do that. Clean up the old node and forego the transformation. 3744 // Ideally this won't happen very often, because instcombine 3745 // and the earlier dagcombine runs (where illegal nodes are 3746 // permitted) should have folded most of them already. 3747 DAG.DeleteNode(Res.getNode()); 3748 } 3749 } 3750 3751 // (conv (conv x, t1), t2) -> (conv x, t2) 3752 if (N0.getOpcode() == ISD::BIT_CONVERT) 3753 return DAG.getNode(ISD::BIT_CONVERT, N->getDebugLoc(), VT, 3754 N0.getOperand(0)); 3755 3756 // fold (conv (load x)) -> (load (conv*)x) 3757 // If the resultant load doesn't need a higher alignment than the original! 3758 if (ISD::isNormalLoad(N0.getNode()) && N0.hasOneUse() && 3759 // Do not change the width of a volatile load. 3760 !cast<LoadSDNode>(N0)->isVolatile() && 3761 (!LegalOperations || TLI.isOperationLegal(ISD::LOAD, VT))) { 3762 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 3763 unsigned Align = TLI.getTargetData()-> 3764 getABITypeAlignment(VT.getTypeForEVT(*DAG.getContext())); 3765 unsigned OrigAlign = LN0->getAlignment(); 3766 3767 if (Align <= OrigAlign) { 3768 SDValue Load = DAG.getLoad(VT, N->getDebugLoc(), LN0->getChain(), 3769 LN0->getBasePtr(), 3770 LN0->getSrcValue(), LN0->getSrcValueOffset(), 3771 LN0->isVolatile(), OrigAlign); 3772 AddToWorkList(N); 3773 CombineTo(N0.getNode(), 3774 DAG.getNode(ISD::BIT_CONVERT, N0.getDebugLoc(), 3775 N0.getValueType(), Load), 3776 Load.getValue(1)); 3777 return Load; 3778 } 3779 } 3780 3781 // fold (bitconvert (fneg x)) -> (xor (bitconvert x), signbit) 3782 // fold (bitconvert (fabs x)) -> (and (bitconvert x), (not signbit)) 3783 // This often reduces constant pool loads. 3784 if ((N0.getOpcode() == ISD::FNEG || N0.getOpcode() == ISD::FABS) && 3785 N0.getNode()->hasOneUse() && VT.isInteger() && !VT.isVector()) { 3786 SDValue NewConv = DAG.getNode(ISD::BIT_CONVERT, N0.getDebugLoc(), VT, 3787 N0.getOperand(0)); 3788 AddToWorkList(NewConv.getNode()); 3789 3790 APInt SignBit = APInt::getSignBit(VT.getSizeInBits()); 3791 if (N0.getOpcode() == ISD::FNEG) 3792 return DAG.getNode(ISD::XOR, N->getDebugLoc(), VT, 3793 NewConv, DAG.getConstant(SignBit, VT)); 3794 assert(N0.getOpcode() == ISD::FABS); 3795 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, 3796 NewConv, DAG.getConstant(~SignBit, VT)); 3797 } 3798 3799 // fold (bitconvert (fcopysign cst, x)) -> 3800 // (or (and (bitconvert x), sign), (and cst, (not sign))) 3801 // Note that we don't handle (copysign x, cst) because this can always be 3802 // folded to an fneg or fabs. 3803 if (N0.getOpcode() == ISD::FCOPYSIGN && N0.getNode()->hasOneUse() && 3804 isa<ConstantFPSDNode>(N0.getOperand(0)) && 3805 VT.isInteger() && !VT.isVector()) { 3806 unsigned OrigXWidth = N0.getOperand(1).getValueType().getSizeInBits(); 3807 EVT IntXVT = EVT::getIntegerVT(*DAG.getContext(), OrigXWidth); 3808 if (TLI.isTypeLegal(IntXVT) || !LegalTypes) { 3809 SDValue X = DAG.getNode(ISD::BIT_CONVERT, N0.getDebugLoc(), 3810 IntXVT, N0.getOperand(1)); 3811 AddToWorkList(X.getNode()); 3812 3813 // If X has a different width than the result/lhs, sext it or truncate it. 3814 unsigned VTWidth = VT.getSizeInBits(); 3815 if (OrigXWidth < VTWidth) { 3816 X = DAG.getNode(ISD::SIGN_EXTEND, N->getDebugLoc(), VT, X); 3817 AddToWorkList(X.getNode()); 3818 } else if (OrigXWidth > VTWidth) { 3819 // To get the sign bit in the right place, we have to shift it right 3820 // before truncating. 3821 X = DAG.getNode(ISD::SRL, X.getDebugLoc(), 3822 X.getValueType(), X, 3823 DAG.getConstant(OrigXWidth-VTWidth, X.getValueType())); 3824 AddToWorkList(X.getNode()); 3825 X = DAG.getNode(ISD::TRUNCATE, X.getDebugLoc(), VT, X); 3826 AddToWorkList(X.getNode()); 3827 } 3828 3829 APInt SignBit = APInt::getSignBit(VT.getSizeInBits()); 3830 X = DAG.getNode(ISD::AND, X.getDebugLoc(), VT, 3831 X, DAG.getConstant(SignBit, VT)); 3832 AddToWorkList(X.getNode()); 3833 3834 SDValue Cst = DAG.getNode(ISD::BIT_CONVERT, N0.getDebugLoc(), 3835 VT, N0.getOperand(0)); 3836 Cst = DAG.getNode(ISD::AND, Cst.getDebugLoc(), VT, 3837 Cst, DAG.getConstant(~SignBit, VT)); 3838 AddToWorkList(Cst.getNode()); 3839 3840 return DAG.getNode(ISD::OR, N->getDebugLoc(), VT, X, Cst); 3841 } 3842 } 3843 3844 // bitconvert(build_pair(ld, ld)) -> ld iff load locations are consecutive. 3845 if (N0.getOpcode() == ISD::BUILD_PAIR) { 3846 SDValue CombineLD = CombineConsecutiveLoads(N0.getNode(), VT); 3847 if (CombineLD.getNode()) 3848 return CombineLD; 3849 } 3850 3851 return SDValue(); 3852} 3853 3854SDValue DAGCombiner::visitBUILD_PAIR(SDNode *N) { 3855 EVT VT = N->getValueType(0); 3856 return CombineConsecutiveLoads(N, VT); 3857} 3858 3859/// ConstantFoldBIT_CONVERTofBUILD_VECTOR - We know that BV is a build_vector 3860/// node with Constant, ConstantFP or Undef operands. DstEltVT indicates the 3861/// destination element value type. 3862SDValue DAGCombiner:: 3863ConstantFoldBIT_CONVERTofBUILD_VECTOR(SDNode *BV, EVT DstEltVT) { 3864 EVT SrcEltVT = BV->getValueType(0).getVectorElementType(); 3865 3866 // If this is already the right type, we're done. 3867 if (SrcEltVT == DstEltVT) return SDValue(BV, 0); 3868 3869 unsigned SrcBitSize = SrcEltVT.getSizeInBits(); 3870 unsigned DstBitSize = DstEltVT.getSizeInBits(); 3871 3872 // If this is a conversion of N elements of one type to N elements of another 3873 // type, convert each element. This handles FP<->INT cases. 3874 if (SrcBitSize == DstBitSize) { 3875 SmallVector<SDValue, 8> Ops; 3876 for (unsigned i = 0, e = BV->getNumOperands(); i != e; ++i) { 3877 SDValue Op = BV->getOperand(i); 3878 // If the vector element type is not legal, the BUILD_VECTOR operands 3879 // are promoted and implicitly truncated. Make that explicit here. 3880 if (Op.getValueType() != SrcEltVT) 3881 Op = DAG.getNode(ISD::TRUNCATE, BV->getDebugLoc(), SrcEltVT, Op); 3882 Ops.push_back(DAG.getNode(ISD::BIT_CONVERT, BV->getDebugLoc(), 3883 DstEltVT, Op)); 3884 AddToWorkList(Ops.back().getNode()); 3885 } 3886 EVT VT = EVT::getVectorVT(*DAG.getContext(), DstEltVT, 3887 BV->getValueType(0).getVectorNumElements()); 3888 return DAG.getNode(ISD::BUILD_VECTOR, BV->getDebugLoc(), VT, 3889 &Ops[0], Ops.size()); 3890 } 3891 3892 // Otherwise, we're growing or shrinking the elements. To avoid having to 3893 // handle annoying details of growing/shrinking FP values, we convert them to 3894 // int first. 3895 if (SrcEltVT.isFloatingPoint()) { 3896 // Convert the input float vector to a int vector where the elements are the 3897 // same sizes. 3898 assert((SrcEltVT == MVT::f32 || SrcEltVT == MVT::f64) && "Unknown FP VT!"); 3899 EVT IntVT = EVT::getIntegerVT(*DAG.getContext(), SrcEltVT.getSizeInBits()); 3900 BV = ConstantFoldBIT_CONVERTofBUILD_VECTOR(BV, IntVT).getNode(); 3901 SrcEltVT = IntVT; 3902 } 3903 3904 // Now we know the input is an integer vector. If the output is a FP type, 3905 // convert to integer first, then to FP of the right size. 3906 if (DstEltVT.isFloatingPoint()) { 3907 assert((DstEltVT == MVT::f32 || DstEltVT == MVT::f64) && "Unknown FP VT!"); 3908 EVT TmpVT = EVT::getIntegerVT(*DAG.getContext(), DstEltVT.getSizeInBits()); 3909 SDNode *Tmp = ConstantFoldBIT_CONVERTofBUILD_VECTOR(BV, TmpVT).getNode(); 3910 3911 // Next, convert to FP elements of the same size. 3912 return ConstantFoldBIT_CONVERTofBUILD_VECTOR(Tmp, DstEltVT); 3913 } 3914 3915 // Okay, we know the src/dst types are both integers of differing types. 3916 // Handling growing first. 3917 assert(SrcEltVT.isInteger() && DstEltVT.isInteger()); 3918 if (SrcBitSize < DstBitSize) { 3919 unsigned NumInputsPerOutput = DstBitSize/SrcBitSize; 3920 3921 SmallVector<SDValue, 8> Ops; 3922 for (unsigned i = 0, e = BV->getNumOperands(); i != e; 3923 i += NumInputsPerOutput) { 3924 bool isLE = TLI.isLittleEndian(); 3925 APInt NewBits = APInt(DstBitSize, 0); 3926 bool EltIsUndef = true; 3927 for (unsigned j = 0; j != NumInputsPerOutput; ++j) { 3928 // Shift the previously computed bits over. 3929 NewBits <<= SrcBitSize; 3930 SDValue Op = BV->getOperand(i+ (isLE ? (NumInputsPerOutput-j-1) : j)); 3931 if (Op.getOpcode() == ISD::UNDEF) continue; 3932 EltIsUndef = false; 3933 3934 NewBits |= (APInt(cast<ConstantSDNode>(Op)->getAPIntValue()). 3935 zextOrTrunc(SrcBitSize).zext(DstBitSize)); 3936 } 3937 3938 if (EltIsUndef) 3939 Ops.push_back(DAG.getUNDEF(DstEltVT)); 3940 else 3941 Ops.push_back(DAG.getConstant(NewBits, DstEltVT)); 3942 } 3943 3944 EVT VT = EVT::getVectorVT(*DAG.getContext(), DstEltVT, Ops.size()); 3945 return DAG.getNode(ISD::BUILD_VECTOR, BV->getDebugLoc(), VT, 3946 &Ops[0], Ops.size()); 3947 } 3948 3949 // Finally, this must be the case where we are shrinking elements: each input 3950 // turns into multiple outputs. 3951 bool isS2V = ISD::isScalarToVector(BV); 3952 unsigned NumOutputsPerInput = SrcBitSize/DstBitSize; 3953 EVT VT = EVT::getVectorVT(*DAG.getContext(), DstEltVT, 3954 NumOutputsPerInput*BV->getNumOperands()); 3955 SmallVector<SDValue, 8> Ops; 3956 3957 for (unsigned i = 0, e = BV->getNumOperands(); i != e; ++i) { 3958 if (BV->getOperand(i).getOpcode() == ISD::UNDEF) { 3959 for (unsigned j = 0; j != NumOutputsPerInput; ++j) 3960 Ops.push_back(DAG.getUNDEF(DstEltVT)); 3961 continue; 3962 } 3963 3964 APInt OpVal = APInt(cast<ConstantSDNode>(BV->getOperand(i))-> 3965 getAPIntValue()).zextOrTrunc(SrcBitSize); 3966 3967 for (unsigned j = 0; j != NumOutputsPerInput; ++j) { 3968 APInt ThisVal = APInt(OpVal).trunc(DstBitSize); 3969 Ops.push_back(DAG.getConstant(ThisVal, DstEltVT)); 3970 if (isS2V && i == 0 && j == 0 && APInt(ThisVal).zext(SrcBitSize) == OpVal) 3971 // Simply turn this into a SCALAR_TO_VECTOR of the new type. 3972 return DAG.getNode(ISD::SCALAR_TO_VECTOR, BV->getDebugLoc(), VT, 3973 Ops[0]); 3974 OpVal = OpVal.lshr(DstBitSize); 3975 } 3976 3977 // For big endian targets, swap the order of the pieces of each element. 3978 if (TLI.isBigEndian()) 3979 std::reverse(Ops.end()-NumOutputsPerInput, Ops.end()); 3980 } 3981 3982 return DAG.getNode(ISD::BUILD_VECTOR, BV->getDebugLoc(), VT, 3983 &Ops[0], Ops.size()); 3984} 3985 3986SDValue DAGCombiner::visitFADD(SDNode *N) { 3987 SDValue N0 = N->getOperand(0); 3988 SDValue N1 = N->getOperand(1); 3989 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 3990 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1); 3991 EVT VT = N->getValueType(0); 3992 3993 // fold vector ops 3994 if (VT.isVector()) { 3995 SDValue FoldedVOp = SimplifyVBinOp(N); 3996 if (FoldedVOp.getNode()) return FoldedVOp; 3997 } 3998 3999 // fold (fadd c1, c2) -> (fadd c1, c2) 4000 if (N0CFP && N1CFP && VT != MVT::ppcf128) 4001 return DAG.getNode(ISD::FADD, N->getDebugLoc(), VT, N0, N1); 4002 // canonicalize constant to RHS 4003 if (N0CFP && !N1CFP) 4004 return DAG.getNode(ISD::FADD, N->getDebugLoc(), VT, N1, N0); 4005 // fold (fadd A, 0) -> A 4006 if (UnsafeFPMath && N1CFP && N1CFP->getValueAPF().isZero()) 4007 return N0; 4008 // fold (fadd A, (fneg B)) -> (fsub A, B) 4009 if (isNegatibleForFree(N1, LegalOperations) == 2) 4010 return DAG.getNode(ISD::FSUB, N->getDebugLoc(), VT, N0, 4011 GetNegatedExpression(N1, DAG, LegalOperations)); 4012 // fold (fadd (fneg A), B) -> (fsub B, A) 4013 if (isNegatibleForFree(N0, LegalOperations) == 2) 4014 return DAG.getNode(ISD::FSUB, N->getDebugLoc(), VT, N1, 4015 GetNegatedExpression(N0, DAG, LegalOperations)); 4016 4017 // If allowed, fold (fadd (fadd x, c1), c2) -> (fadd x, (fadd c1, c2)) 4018 if (UnsafeFPMath && N1CFP && N0.getOpcode() == ISD::FADD && 4019 N0.getNode()->hasOneUse() && isa<ConstantFPSDNode>(N0.getOperand(1))) 4020 return DAG.getNode(ISD::FADD, N->getDebugLoc(), VT, N0.getOperand(0), 4021 DAG.getNode(ISD::FADD, N->getDebugLoc(), VT, 4022 N0.getOperand(1), N1)); 4023 4024 return SDValue(); 4025} 4026 4027SDValue DAGCombiner::visitFSUB(SDNode *N) { 4028 SDValue N0 = N->getOperand(0); 4029 SDValue N1 = N->getOperand(1); 4030 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 4031 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1); 4032 EVT VT = N->getValueType(0); 4033 4034 // fold vector ops 4035 if (VT.isVector()) { 4036 SDValue FoldedVOp = SimplifyVBinOp(N); 4037 if (FoldedVOp.getNode()) return FoldedVOp; 4038 } 4039 4040 // fold (fsub c1, c2) -> c1-c2 4041 if (N0CFP && N1CFP && VT != MVT::ppcf128) 4042 return DAG.getNode(ISD::FSUB, N->getDebugLoc(), VT, N0, N1); 4043 // fold (fsub A, 0) -> A 4044 if (UnsafeFPMath && N1CFP && N1CFP->getValueAPF().isZero()) 4045 return N0; 4046 // fold (fsub 0, B) -> -B 4047 if (UnsafeFPMath && N0CFP && N0CFP->getValueAPF().isZero()) { 4048 if (isNegatibleForFree(N1, LegalOperations)) 4049 return GetNegatedExpression(N1, DAG, LegalOperations); 4050 if (!LegalOperations || TLI.isOperationLegal(ISD::FNEG, VT)) 4051 return DAG.getNode(ISD::FNEG, N->getDebugLoc(), VT, N1); 4052 } 4053 // fold (fsub A, (fneg B)) -> (fadd A, B) 4054 if (isNegatibleForFree(N1, LegalOperations)) 4055 return DAG.getNode(ISD::FADD, N->getDebugLoc(), VT, N0, 4056 GetNegatedExpression(N1, DAG, LegalOperations)); 4057 4058 return SDValue(); 4059} 4060 4061SDValue DAGCombiner::visitFMUL(SDNode *N) { 4062 SDValue N0 = N->getOperand(0); 4063 SDValue N1 = N->getOperand(1); 4064 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 4065 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1); 4066 EVT VT = N->getValueType(0); 4067 4068 // fold vector ops 4069 if (VT.isVector()) { 4070 SDValue FoldedVOp = SimplifyVBinOp(N); 4071 if (FoldedVOp.getNode()) return FoldedVOp; 4072 } 4073 4074 // fold (fmul c1, c2) -> c1*c2 4075 if (N0CFP && N1CFP && VT != MVT::ppcf128) 4076 return DAG.getNode(ISD::FMUL, N->getDebugLoc(), VT, N0, N1); 4077 // canonicalize constant to RHS 4078 if (N0CFP && !N1CFP) 4079 return DAG.getNode(ISD::FMUL, N->getDebugLoc(), VT, N1, N0); 4080 // fold (fmul A, 0) -> 0 4081 if (UnsafeFPMath && N1CFP && N1CFP->getValueAPF().isZero()) 4082 return N1; 4083 // fold (fmul A, 0) -> 0, vector edition. 4084 if (UnsafeFPMath && ISD::isBuildVectorAllZeros(N1.getNode())) 4085 return N1; 4086 // fold (fmul X, 2.0) -> (fadd X, X) 4087 if (N1CFP && N1CFP->isExactlyValue(+2.0)) 4088 return DAG.getNode(ISD::FADD, N->getDebugLoc(), VT, N0, N0); 4089 // fold (fmul X, -1.0) -> (fneg X) 4090 if (N1CFP && N1CFP->isExactlyValue(-1.0)) 4091 if (!LegalOperations || TLI.isOperationLegal(ISD::FNEG, VT)) 4092 return DAG.getNode(ISD::FNEG, N->getDebugLoc(), VT, N0); 4093 4094 // fold (fmul (fneg X), (fneg Y)) -> (fmul X, Y) 4095 if (char LHSNeg = isNegatibleForFree(N0, LegalOperations)) { 4096 if (char RHSNeg = isNegatibleForFree(N1, LegalOperations)) { 4097 // Both can be negated for free, check to see if at least one is cheaper 4098 // negated. 4099 if (LHSNeg == 2 || RHSNeg == 2) 4100 return DAG.getNode(ISD::FMUL, N->getDebugLoc(), VT, 4101 GetNegatedExpression(N0, DAG, LegalOperations), 4102 GetNegatedExpression(N1, DAG, LegalOperations)); 4103 } 4104 } 4105 4106 // If allowed, fold (fmul (fmul x, c1), c2) -> (fmul x, (fmul c1, c2)) 4107 if (UnsafeFPMath && N1CFP && N0.getOpcode() == ISD::FMUL && 4108 N0.getNode()->hasOneUse() && isa<ConstantFPSDNode>(N0.getOperand(1))) 4109 return DAG.getNode(ISD::FMUL, N->getDebugLoc(), VT, N0.getOperand(0), 4110 DAG.getNode(ISD::FMUL, N->getDebugLoc(), VT, 4111 N0.getOperand(1), N1)); 4112 4113 return SDValue(); 4114} 4115 4116SDValue DAGCombiner::visitFDIV(SDNode *N) { 4117 SDValue N0 = N->getOperand(0); 4118 SDValue N1 = N->getOperand(1); 4119 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 4120 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1); 4121 EVT VT = N->getValueType(0); 4122 4123 // fold vector ops 4124 if (VT.isVector()) { 4125 SDValue FoldedVOp = SimplifyVBinOp(N); 4126 if (FoldedVOp.getNode()) return FoldedVOp; 4127 } 4128 4129 // fold (fdiv c1, c2) -> c1/c2 4130 if (N0CFP && N1CFP && VT != MVT::ppcf128) 4131 return DAG.getNode(ISD::FDIV, N->getDebugLoc(), VT, N0, N1); 4132 4133 4134 // (fdiv (fneg X), (fneg Y)) -> (fdiv X, Y) 4135 if (char LHSNeg = isNegatibleForFree(N0, LegalOperations)) { 4136 if (char RHSNeg = isNegatibleForFree(N1, LegalOperations)) { 4137 // Both can be negated for free, check to see if at least one is cheaper 4138 // negated. 4139 if (LHSNeg == 2 || RHSNeg == 2) 4140 return DAG.getNode(ISD::FDIV, N->getDebugLoc(), VT, 4141 GetNegatedExpression(N0, DAG, LegalOperations), 4142 GetNegatedExpression(N1, DAG, LegalOperations)); 4143 } 4144 } 4145 4146 return SDValue(); 4147} 4148 4149SDValue DAGCombiner::visitFREM(SDNode *N) { 4150 SDValue N0 = N->getOperand(0); 4151 SDValue N1 = N->getOperand(1); 4152 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 4153 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1); 4154 EVT VT = N->getValueType(0); 4155 4156 // fold (frem c1, c2) -> fmod(c1,c2) 4157 if (N0CFP && N1CFP && VT != MVT::ppcf128) 4158 return DAG.getNode(ISD::FREM, N->getDebugLoc(), VT, N0, N1); 4159 4160 return SDValue(); 4161} 4162 4163SDValue DAGCombiner::visitFCOPYSIGN(SDNode *N) { 4164 SDValue N0 = N->getOperand(0); 4165 SDValue N1 = N->getOperand(1); 4166 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 4167 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1); 4168 EVT VT = N->getValueType(0); 4169 4170 if (N0CFP && N1CFP && VT != MVT::ppcf128) // Constant fold 4171 return DAG.getNode(ISD::FCOPYSIGN, N->getDebugLoc(), VT, N0, N1); 4172 4173 if (N1CFP) { 4174 const APFloat& V = N1CFP->getValueAPF(); 4175 // copysign(x, c1) -> fabs(x) iff ispos(c1) 4176 // copysign(x, c1) -> fneg(fabs(x)) iff isneg(c1) 4177 if (!V.isNegative()) { 4178 if (!LegalOperations || TLI.isOperationLegal(ISD::FABS, VT)) 4179 return DAG.getNode(ISD::FABS, N->getDebugLoc(), VT, N0); 4180 } else { 4181 if (!LegalOperations || TLI.isOperationLegal(ISD::FNEG, VT)) 4182 return DAG.getNode(ISD::FNEG, N->getDebugLoc(), VT, 4183 DAG.getNode(ISD::FABS, N0.getDebugLoc(), VT, N0)); 4184 } 4185 } 4186 4187 // copysign(fabs(x), y) -> copysign(x, y) 4188 // copysign(fneg(x), y) -> copysign(x, y) 4189 // copysign(copysign(x,z), y) -> copysign(x, y) 4190 if (N0.getOpcode() == ISD::FABS || N0.getOpcode() == ISD::FNEG || 4191 N0.getOpcode() == ISD::FCOPYSIGN) 4192 return DAG.getNode(ISD::FCOPYSIGN, N->getDebugLoc(), VT, 4193 N0.getOperand(0), N1); 4194 4195 // copysign(x, abs(y)) -> abs(x) 4196 if (N1.getOpcode() == ISD::FABS) 4197 return DAG.getNode(ISD::FABS, N->getDebugLoc(), VT, N0); 4198 4199 // copysign(x, copysign(y,z)) -> copysign(x, z) 4200 if (N1.getOpcode() == ISD::FCOPYSIGN) 4201 return DAG.getNode(ISD::FCOPYSIGN, N->getDebugLoc(), VT, 4202 N0, N1.getOperand(1)); 4203 4204 // copysign(x, fp_extend(y)) -> copysign(x, y) 4205 // copysign(x, fp_round(y)) -> copysign(x, y) 4206 if (N1.getOpcode() == ISD::FP_EXTEND || N1.getOpcode() == ISD::FP_ROUND) 4207 return DAG.getNode(ISD::FCOPYSIGN, N->getDebugLoc(), VT, 4208 N0, N1.getOperand(0)); 4209 4210 return SDValue(); 4211} 4212 4213SDValue DAGCombiner::visitSINT_TO_FP(SDNode *N) { 4214 SDValue N0 = N->getOperand(0); 4215 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 4216 EVT VT = N->getValueType(0); 4217 EVT OpVT = N0.getValueType(); 4218 4219 // fold (sint_to_fp c1) -> c1fp 4220 if (N0C && OpVT != MVT::ppcf128) 4221 return DAG.getNode(ISD::SINT_TO_FP, N->getDebugLoc(), VT, N0); 4222 4223 // If the input is a legal type, and SINT_TO_FP is not legal on this target, 4224 // but UINT_TO_FP is legal on this target, try to convert. 4225 if (!TLI.isOperationLegalOrCustom(ISD::SINT_TO_FP, OpVT) && 4226 TLI.isOperationLegalOrCustom(ISD::UINT_TO_FP, OpVT)) { 4227 // If the sign bit is known to be zero, we can change this to UINT_TO_FP. 4228 if (DAG.SignBitIsZero(N0)) 4229 return DAG.getNode(ISD::UINT_TO_FP, N->getDebugLoc(), VT, N0); 4230 } 4231 4232 return SDValue(); 4233} 4234 4235SDValue DAGCombiner::visitUINT_TO_FP(SDNode *N) { 4236 SDValue N0 = N->getOperand(0); 4237 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 4238 EVT VT = N->getValueType(0); 4239 EVT OpVT = N0.getValueType(); 4240 4241 // fold (uint_to_fp c1) -> c1fp 4242 if (N0C && OpVT != MVT::ppcf128) 4243 return DAG.getNode(ISD::UINT_TO_FP, N->getDebugLoc(), VT, N0); 4244 4245 // If the input is a legal type, and UINT_TO_FP is not legal on this target, 4246 // but SINT_TO_FP is legal on this target, try to convert. 4247 if (!TLI.isOperationLegalOrCustom(ISD::UINT_TO_FP, OpVT) && 4248 TLI.isOperationLegalOrCustom(ISD::SINT_TO_FP, OpVT)) { 4249 // If the sign bit is known to be zero, we can change this to SINT_TO_FP. 4250 if (DAG.SignBitIsZero(N0)) 4251 return DAG.getNode(ISD::SINT_TO_FP, N->getDebugLoc(), VT, N0); 4252 } 4253 4254 return SDValue(); 4255} 4256 4257SDValue DAGCombiner::visitFP_TO_SINT(SDNode *N) { 4258 SDValue N0 = N->getOperand(0); 4259 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 4260 EVT VT = N->getValueType(0); 4261 4262 // fold (fp_to_sint c1fp) -> c1 4263 if (N0CFP) 4264 return DAG.getNode(ISD::FP_TO_SINT, N->getDebugLoc(), VT, N0); 4265 4266 return SDValue(); 4267} 4268 4269SDValue DAGCombiner::visitFP_TO_UINT(SDNode *N) { 4270 SDValue N0 = N->getOperand(0); 4271 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 4272 EVT VT = N->getValueType(0); 4273 4274 // fold (fp_to_uint c1fp) -> c1 4275 if (N0CFP && VT != MVT::ppcf128) 4276 return DAG.getNode(ISD::FP_TO_UINT, N->getDebugLoc(), VT, N0); 4277 4278 return SDValue(); 4279} 4280 4281SDValue DAGCombiner::visitFP_ROUND(SDNode *N) { 4282 SDValue N0 = N->getOperand(0); 4283 SDValue N1 = N->getOperand(1); 4284 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 4285 EVT VT = N->getValueType(0); 4286 4287 // fold (fp_round c1fp) -> c1fp 4288 if (N0CFP && N0.getValueType() != MVT::ppcf128) 4289 return DAG.getNode(ISD::FP_ROUND, N->getDebugLoc(), VT, N0, N1); 4290 4291 // fold (fp_round (fp_extend x)) -> x 4292 if (N0.getOpcode() == ISD::FP_EXTEND && VT == N0.getOperand(0).getValueType()) 4293 return N0.getOperand(0); 4294 4295 // fold (fp_round (fp_round x)) -> (fp_round x) 4296 if (N0.getOpcode() == ISD::FP_ROUND) { 4297 // This is a value preserving truncation if both round's are. 4298 bool IsTrunc = N->getConstantOperandVal(1) == 1 && 4299 N0.getNode()->getConstantOperandVal(1) == 1; 4300 return DAG.getNode(ISD::FP_ROUND, N->getDebugLoc(), VT, N0.getOperand(0), 4301 DAG.getIntPtrConstant(IsTrunc)); 4302 } 4303 4304 // fold (fp_round (copysign X, Y)) -> (copysign (fp_round X), Y) 4305 if (N0.getOpcode() == ISD::FCOPYSIGN && N0.getNode()->hasOneUse()) { 4306 SDValue Tmp = DAG.getNode(ISD::FP_ROUND, N0.getDebugLoc(), VT, 4307 N0.getOperand(0), N1); 4308 AddToWorkList(Tmp.getNode()); 4309 return DAG.getNode(ISD::FCOPYSIGN, N->getDebugLoc(), VT, 4310 Tmp, N0.getOperand(1)); 4311 } 4312 4313 return SDValue(); 4314} 4315 4316SDValue DAGCombiner::visitFP_ROUND_INREG(SDNode *N) { 4317 SDValue N0 = N->getOperand(0); 4318 EVT VT = N->getValueType(0); 4319 EVT EVT = cast<VTSDNode>(N->getOperand(1))->getVT(); 4320 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 4321 4322 // fold (fp_round_inreg c1fp) -> c1fp 4323 if (N0CFP && (TLI.isTypeLegal(EVT) || !LegalTypes)) { 4324 SDValue Round = DAG.getConstantFP(*N0CFP->getConstantFPValue(), EVT); 4325 return DAG.getNode(ISD::FP_EXTEND, N->getDebugLoc(), VT, Round); 4326 } 4327 4328 return SDValue(); 4329} 4330 4331SDValue DAGCombiner::visitFP_EXTEND(SDNode *N) { 4332 SDValue N0 = N->getOperand(0); 4333 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 4334 EVT VT = N->getValueType(0); 4335 4336 // If this is fp_round(fpextend), don't fold it, allow ourselves to be folded. 4337 if (N->hasOneUse() && 4338 N->use_begin()->getOpcode() == ISD::FP_ROUND) 4339 return SDValue(); 4340 4341 // fold (fp_extend c1fp) -> c1fp 4342 if (N0CFP && VT != MVT::ppcf128) 4343 return DAG.getNode(ISD::FP_EXTEND, N->getDebugLoc(), VT, N0); 4344 4345 // Turn fp_extend(fp_round(X, 1)) -> x since the fp_round doesn't affect the 4346 // value of X. 4347 if (N0.getOpcode() == ISD::FP_ROUND 4348 && N0.getNode()->getConstantOperandVal(1) == 1) { 4349 SDValue In = N0.getOperand(0); 4350 if (In.getValueType() == VT) return In; 4351 if (VT.bitsLT(In.getValueType())) 4352 return DAG.getNode(ISD::FP_ROUND, N->getDebugLoc(), VT, 4353 In, N0.getOperand(1)); 4354 return DAG.getNode(ISD::FP_EXTEND, N->getDebugLoc(), VT, In); 4355 } 4356 4357 // fold (fpext (load x)) -> (fpext (fptrunc (extload x))) 4358 if (ISD::isNON_EXTLoad(N0.getNode()) && N0.hasOneUse() && 4359 ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) || 4360 TLI.isLoadExtLegal(ISD::EXTLOAD, N0.getValueType()))) { 4361 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 4362 SDValue ExtLoad = DAG.getExtLoad(ISD::EXTLOAD, N->getDebugLoc(), VT, 4363 LN0->getChain(), 4364 LN0->getBasePtr(), LN0->getSrcValue(), 4365 LN0->getSrcValueOffset(), 4366 N0.getValueType(), 4367 LN0->isVolatile(), LN0->getAlignment()); 4368 CombineTo(N, ExtLoad); 4369 CombineTo(N0.getNode(), 4370 DAG.getNode(ISD::FP_ROUND, N0.getDebugLoc(), 4371 N0.getValueType(), ExtLoad, DAG.getIntPtrConstant(1)), 4372 ExtLoad.getValue(1)); 4373 return SDValue(N, 0); // Return N so it doesn't get rechecked! 4374 } 4375 4376 return SDValue(); 4377} 4378 4379SDValue DAGCombiner::visitFNEG(SDNode *N) { 4380 SDValue N0 = N->getOperand(0); 4381 EVT VT = N->getValueType(0); 4382 4383 if (isNegatibleForFree(N0, LegalOperations)) 4384 return GetNegatedExpression(N0, DAG, LegalOperations); 4385 4386 // Transform fneg(bitconvert(x)) -> bitconvert(x^sign) to avoid loading 4387 // constant pool values. 4388 if (N0.getOpcode() == ISD::BIT_CONVERT && 4389 !VT.isVector() && 4390 N0.getNode()->hasOneUse() && 4391 N0.getOperand(0).getValueType().isInteger()) { 4392 SDValue Int = N0.getOperand(0); 4393 EVT IntVT = Int.getValueType(); 4394 if (IntVT.isInteger() && !IntVT.isVector()) { 4395 Int = DAG.getNode(ISD::XOR, N0.getDebugLoc(), IntVT, Int, 4396 DAG.getConstant(APInt::getSignBit(IntVT.getSizeInBits()), IntVT)); 4397 AddToWorkList(Int.getNode()); 4398 return DAG.getNode(ISD::BIT_CONVERT, N->getDebugLoc(), 4399 VT, Int); 4400 } 4401 } 4402 4403 return SDValue(); 4404} 4405 4406SDValue DAGCombiner::visitFABS(SDNode *N) { 4407 SDValue N0 = N->getOperand(0); 4408 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 4409 EVT VT = N->getValueType(0); 4410 4411 // fold (fabs c1) -> fabs(c1) 4412 if (N0CFP && VT != MVT::ppcf128) 4413 return DAG.getNode(ISD::FABS, N->getDebugLoc(), VT, N0); 4414 // fold (fabs (fabs x)) -> (fabs x) 4415 if (N0.getOpcode() == ISD::FABS) 4416 return N->getOperand(0); 4417 // fold (fabs (fneg x)) -> (fabs x) 4418 // fold (fabs (fcopysign x, y)) -> (fabs x) 4419 if (N0.getOpcode() == ISD::FNEG || N0.getOpcode() == ISD::FCOPYSIGN) 4420 return DAG.getNode(ISD::FABS, N->getDebugLoc(), VT, N0.getOperand(0)); 4421 4422 // Transform fabs(bitconvert(x)) -> bitconvert(x&~sign) to avoid loading 4423 // constant pool values. 4424 if (N0.getOpcode() == ISD::BIT_CONVERT && N0.getNode()->hasOneUse() && 4425 N0.getOperand(0).getValueType().isInteger() && 4426 !N0.getOperand(0).getValueType().isVector()) { 4427 SDValue Int = N0.getOperand(0); 4428 EVT IntVT = Int.getValueType(); 4429 if (IntVT.isInteger() && !IntVT.isVector()) { 4430 Int = DAG.getNode(ISD::AND, N0.getDebugLoc(), IntVT, Int, 4431 DAG.getConstant(~APInt::getSignBit(IntVT.getSizeInBits()), IntVT)); 4432 AddToWorkList(Int.getNode()); 4433 return DAG.getNode(ISD::BIT_CONVERT, N->getDebugLoc(), 4434 N->getValueType(0), Int); 4435 } 4436 } 4437 4438 return SDValue(); 4439} 4440 4441SDValue DAGCombiner::visitBRCOND(SDNode *N) { 4442 SDValue Chain = N->getOperand(0); 4443 SDValue N1 = N->getOperand(1); 4444 SDValue N2 = N->getOperand(2); 4445 4446 // If N is a constant we could fold this into a fallthrough or unconditional 4447 // branch. However that doesn't happen very often in normal code, because 4448 // Instcombine/SimplifyCFG should have handled the available opportunities. 4449 // If we did this folding here, it would be necessary to update the 4450 // MachineBasicBlock CFG, which is awkward. 4451 4452 // fold a brcond with a setcc condition into a BR_CC node if BR_CC is legal 4453 // on the target. 4454 if (N1.getOpcode() == ISD::SETCC && 4455 TLI.isOperationLegalOrCustom(ISD::BR_CC, MVT::Other)) { 4456 return DAG.getNode(ISD::BR_CC, N->getDebugLoc(), MVT::Other, 4457 Chain, N1.getOperand(2), 4458 N1.getOperand(0), N1.getOperand(1), N2); 4459 } 4460 4461 if (N1.hasOneUse() && N1.getOpcode() == ISD::SRL) { 4462 // Match this pattern so that we can generate simpler code: 4463 // 4464 // %a = ... 4465 // %b = and i32 %a, 2 4466 // %c = srl i32 %b, 1 4467 // brcond i32 %c ... 4468 // 4469 // into 4470 // 4471 // %a = ... 4472 // %b = and %a, 2 4473 // %c = setcc eq %b, 0 4474 // brcond %c ... 4475 // 4476 // This applies only when the AND constant value has one bit set and the 4477 // SRL constant is equal to the log2 of the AND constant. The back-end is 4478 // smart enough to convert the result into a TEST/JMP sequence. 4479 SDValue Op0 = N1.getOperand(0); 4480 SDValue Op1 = N1.getOperand(1); 4481 4482 if (Op0.getOpcode() == ISD::AND && 4483 Op0.hasOneUse() && 4484 Op1.getOpcode() == ISD::Constant) { 4485 SDValue AndOp1 = Op0.getOperand(1); 4486 4487 if (AndOp1.getOpcode() == ISD::Constant) { 4488 const APInt &AndConst = cast<ConstantSDNode>(AndOp1)->getAPIntValue(); 4489 4490 if (AndConst.isPowerOf2() && 4491 cast<ConstantSDNode>(Op1)->getAPIntValue()==AndConst.logBase2()) { 4492 SDValue SetCC = 4493 DAG.getSetCC(N->getDebugLoc(), 4494 TLI.getSetCCResultType(Op0.getValueType()), 4495 Op0, DAG.getConstant(0, Op0.getValueType()), 4496 ISD::SETNE); 4497 4498 // Replace the uses of SRL with SETCC 4499 DAG.ReplaceAllUsesOfValueWith(N1, SetCC); 4500 removeFromWorkList(N1.getNode()); 4501 DAG.DeleteNode(N1.getNode()); 4502 return DAG.getNode(ISD::BRCOND, N->getDebugLoc(), 4503 MVT::Other, Chain, SetCC, N2); 4504 } 4505 } 4506 } 4507 } 4508 4509 return SDValue(); 4510} 4511 4512// Operand List for BR_CC: Chain, CondCC, CondLHS, CondRHS, DestBB. 4513// 4514SDValue DAGCombiner::visitBR_CC(SDNode *N) { 4515 CondCodeSDNode *CC = cast<CondCodeSDNode>(N->getOperand(1)); 4516 SDValue CondLHS = N->getOperand(2), CondRHS = N->getOperand(3); 4517 4518 // If N is a constant we could fold this into a fallthrough or unconditional 4519 // branch. However that doesn't happen very often in normal code, because 4520 // Instcombine/SimplifyCFG should have handled the available opportunities. 4521 // If we did this folding here, it would be necessary to update the 4522 // MachineBasicBlock CFG, which is awkward. 4523 4524 // Use SimplifySetCC to simplify SETCC's. 4525 SDValue Simp = SimplifySetCC(TLI.getSetCCResultType(CondLHS.getValueType()), 4526 CondLHS, CondRHS, CC->get(), N->getDebugLoc(), 4527 false); 4528 if (Simp.getNode()) AddToWorkList(Simp.getNode()); 4529 4530 // fold to a simpler setcc 4531 if (Simp.getNode() && Simp.getOpcode() == ISD::SETCC) 4532 return DAG.getNode(ISD::BR_CC, N->getDebugLoc(), MVT::Other, 4533 N->getOperand(0), Simp.getOperand(2), 4534 Simp.getOperand(0), Simp.getOperand(1), 4535 N->getOperand(4)); 4536 4537 return SDValue(); 4538} 4539 4540/// CombineToPreIndexedLoadStore - Try turning a load / store into a 4541/// pre-indexed load / store when the base pointer is an add or subtract 4542/// and it has other uses besides the load / store. After the 4543/// transformation, the new indexed load / store has effectively folded 4544/// the add / subtract in and all of its other uses are redirected to the 4545/// new load / store. 4546bool DAGCombiner::CombineToPreIndexedLoadStore(SDNode *N) { 4547 if (!LegalOperations) 4548 return false; 4549 4550 bool isLoad = true; 4551 SDValue Ptr; 4552 EVT VT; 4553 if (LoadSDNode *LD = dyn_cast<LoadSDNode>(N)) { 4554 if (LD->isIndexed()) 4555 return false; 4556 VT = LD->getMemoryVT(); 4557 if (!TLI.isIndexedLoadLegal(ISD::PRE_INC, VT) && 4558 !TLI.isIndexedLoadLegal(ISD::PRE_DEC, VT)) 4559 return false; 4560 Ptr = LD->getBasePtr(); 4561 } else if (StoreSDNode *ST = dyn_cast<StoreSDNode>(N)) { 4562 if (ST->isIndexed()) 4563 return false; 4564 VT = ST->getMemoryVT(); 4565 if (!TLI.isIndexedStoreLegal(ISD::PRE_INC, VT) && 4566 !TLI.isIndexedStoreLegal(ISD::PRE_DEC, VT)) 4567 return false; 4568 Ptr = ST->getBasePtr(); 4569 isLoad = false; 4570 } else { 4571 return false; 4572 } 4573 4574 // If the pointer is not an add/sub, or if it doesn't have multiple uses, bail 4575 // out. There is no reason to make this a preinc/predec. 4576 if ((Ptr.getOpcode() != ISD::ADD && Ptr.getOpcode() != ISD::SUB) || 4577 Ptr.getNode()->hasOneUse()) 4578 return false; 4579 4580 // Ask the target to do addressing mode selection. 4581 SDValue BasePtr; 4582 SDValue Offset; 4583 ISD::MemIndexedMode AM = ISD::UNINDEXED; 4584 if (!TLI.getPreIndexedAddressParts(N, BasePtr, Offset, AM, DAG)) 4585 return false; 4586 // Don't create a indexed load / store with zero offset. 4587 if (isa<ConstantSDNode>(Offset) && 4588 cast<ConstantSDNode>(Offset)->isNullValue()) 4589 return false; 4590 4591 // Try turning it into a pre-indexed load / store except when: 4592 // 1) The new base ptr is a frame index. 4593 // 2) If N is a store and the new base ptr is either the same as or is a 4594 // predecessor of the value being stored. 4595 // 3) Another use of old base ptr is a predecessor of N. If ptr is folded 4596 // that would create a cycle. 4597 // 4) All uses are load / store ops that use it as old base ptr. 4598 4599 // Check #1. Preinc'ing a frame index would require copying the stack pointer 4600 // (plus the implicit offset) to a register to preinc anyway. 4601 if (isa<FrameIndexSDNode>(BasePtr) || isa<RegisterSDNode>(BasePtr)) 4602 return false; 4603 4604 // Check #2. 4605 if (!isLoad) { 4606 SDValue Val = cast<StoreSDNode>(N)->getValue(); 4607 if (Val == BasePtr || BasePtr.getNode()->isPredecessorOf(Val.getNode())) 4608 return false; 4609 } 4610 4611 // Now check for #3 and #4. 4612 bool RealUse = false; 4613 for (SDNode::use_iterator I = Ptr.getNode()->use_begin(), 4614 E = Ptr.getNode()->use_end(); I != E; ++I) { 4615 SDNode *Use = *I; 4616 if (Use == N) 4617 continue; 4618 if (Use->isPredecessorOf(N)) 4619 return false; 4620 4621 if (!((Use->getOpcode() == ISD::LOAD && 4622 cast<LoadSDNode>(Use)->getBasePtr() == Ptr) || 4623 (Use->getOpcode() == ISD::STORE && 4624 cast<StoreSDNode>(Use)->getBasePtr() == Ptr))) 4625 RealUse = true; 4626 } 4627 4628 if (!RealUse) 4629 return false; 4630 4631 SDValue Result; 4632 if (isLoad) 4633 Result = DAG.getIndexedLoad(SDValue(N,0), N->getDebugLoc(), 4634 BasePtr, Offset, AM); 4635 else 4636 Result = DAG.getIndexedStore(SDValue(N,0), N->getDebugLoc(), 4637 BasePtr, Offset, AM); 4638 ++PreIndexedNodes; 4639 ++NodesCombined; 4640 DEBUG(errs() << "\nReplacing.4 "; 4641 N->dump(&DAG); 4642 errs() << "\nWith: "; 4643 Result.getNode()->dump(&DAG); 4644 errs() << '\n'); 4645 WorkListRemover DeadNodes(*this); 4646 if (isLoad) { 4647 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Result.getValue(0), 4648 &DeadNodes); 4649 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), Result.getValue(2), 4650 &DeadNodes); 4651 } else { 4652 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Result.getValue(1), 4653 &DeadNodes); 4654 } 4655 4656 // Finally, since the node is now dead, remove it from the graph. 4657 DAG.DeleteNode(N); 4658 4659 // Replace the uses of Ptr with uses of the updated base value. 4660 DAG.ReplaceAllUsesOfValueWith(Ptr, Result.getValue(isLoad ? 1 : 0), 4661 &DeadNodes); 4662 removeFromWorkList(Ptr.getNode()); 4663 DAG.DeleteNode(Ptr.getNode()); 4664 4665 return true; 4666} 4667 4668/// CombineToPostIndexedLoadStore - Try to combine a load / store with a 4669/// add / sub of the base pointer node into a post-indexed load / store. 4670/// The transformation folded the add / subtract into the new indexed 4671/// load / store effectively and all of its uses are redirected to the 4672/// new load / store. 4673bool DAGCombiner::CombineToPostIndexedLoadStore(SDNode *N) { 4674 if (!LegalOperations) 4675 return false; 4676 4677 bool isLoad = true; 4678 SDValue Ptr; 4679 EVT VT; 4680 if (LoadSDNode *LD = dyn_cast<LoadSDNode>(N)) { 4681 if (LD->isIndexed()) 4682 return false; 4683 VT = LD->getMemoryVT(); 4684 if (!TLI.isIndexedLoadLegal(ISD::POST_INC, VT) && 4685 !TLI.isIndexedLoadLegal(ISD::POST_DEC, VT)) 4686 return false; 4687 Ptr = LD->getBasePtr(); 4688 } else if (StoreSDNode *ST = dyn_cast<StoreSDNode>(N)) { 4689 if (ST->isIndexed()) 4690 return false; 4691 VT = ST->getMemoryVT(); 4692 if (!TLI.isIndexedStoreLegal(ISD::POST_INC, VT) && 4693 !TLI.isIndexedStoreLegal(ISD::POST_DEC, VT)) 4694 return false; 4695 Ptr = ST->getBasePtr(); 4696 isLoad = false; 4697 } else { 4698 return false; 4699 } 4700 4701 if (Ptr.getNode()->hasOneUse()) 4702 return false; 4703 4704 for (SDNode::use_iterator I = Ptr.getNode()->use_begin(), 4705 E = Ptr.getNode()->use_end(); I != E; ++I) { 4706 SDNode *Op = *I; 4707 if (Op == N || 4708 (Op->getOpcode() != ISD::ADD && Op->getOpcode() != ISD::SUB)) 4709 continue; 4710 4711 SDValue BasePtr; 4712 SDValue Offset; 4713 ISD::MemIndexedMode AM = ISD::UNINDEXED; 4714 if (TLI.getPostIndexedAddressParts(N, Op, BasePtr, Offset, AM, DAG)) { 4715 if (Ptr == Offset && Op->getOpcode() == ISD::ADD) 4716 std::swap(BasePtr, Offset); 4717 if (Ptr != BasePtr) 4718 continue; 4719 // Don't create a indexed load / store with zero offset. 4720 if (isa<ConstantSDNode>(Offset) && 4721 cast<ConstantSDNode>(Offset)->isNullValue()) 4722 continue; 4723 4724 // Try turning it into a post-indexed load / store except when 4725 // 1) All uses are load / store ops that use it as base ptr. 4726 // 2) Op must be independent of N, i.e. Op is neither a predecessor 4727 // nor a successor of N. Otherwise, if Op is folded that would 4728 // create a cycle. 4729 4730 if (isa<FrameIndexSDNode>(BasePtr) || isa<RegisterSDNode>(BasePtr)) 4731 continue; 4732 4733 // Check for #1. 4734 bool TryNext = false; 4735 for (SDNode::use_iterator II = BasePtr.getNode()->use_begin(), 4736 EE = BasePtr.getNode()->use_end(); II != EE; ++II) { 4737 SDNode *Use = *II; 4738 if (Use == Ptr.getNode()) 4739 continue; 4740 4741 // If all the uses are load / store addresses, then don't do the 4742 // transformation. 4743 if (Use->getOpcode() == ISD::ADD || Use->getOpcode() == ISD::SUB){ 4744 bool RealUse = false; 4745 for (SDNode::use_iterator III = Use->use_begin(), 4746 EEE = Use->use_end(); III != EEE; ++III) { 4747 SDNode *UseUse = *III; 4748 if (!((UseUse->getOpcode() == ISD::LOAD && 4749 cast<LoadSDNode>(UseUse)->getBasePtr().getNode() == Use) || 4750 (UseUse->getOpcode() == ISD::STORE && 4751 cast<StoreSDNode>(UseUse)->getBasePtr().getNode() == Use))) 4752 RealUse = true; 4753 } 4754 4755 if (!RealUse) { 4756 TryNext = true; 4757 break; 4758 } 4759 } 4760 } 4761 4762 if (TryNext) 4763 continue; 4764 4765 // Check for #2 4766 if (!Op->isPredecessorOf(N) && !N->isPredecessorOf(Op)) { 4767 SDValue Result = isLoad 4768 ? DAG.getIndexedLoad(SDValue(N,0), N->getDebugLoc(), 4769 BasePtr, Offset, AM) 4770 : DAG.getIndexedStore(SDValue(N,0), N->getDebugLoc(), 4771 BasePtr, Offset, AM); 4772 ++PostIndexedNodes; 4773 ++NodesCombined; 4774 DEBUG(errs() << "\nReplacing.5 "; 4775 N->dump(&DAG); 4776 errs() << "\nWith: "; 4777 Result.getNode()->dump(&DAG); 4778 errs() << '\n'); 4779 WorkListRemover DeadNodes(*this); 4780 if (isLoad) { 4781 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Result.getValue(0), 4782 &DeadNodes); 4783 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), Result.getValue(2), 4784 &DeadNodes); 4785 } else { 4786 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Result.getValue(1), 4787 &DeadNodes); 4788 } 4789 4790 // Finally, since the node is now dead, remove it from the graph. 4791 DAG.DeleteNode(N); 4792 4793 // Replace the uses of Use with uses of the updated base value. 4794 DAG.ReplaceAllUsesOfValueWith(SDValue(Op, 0), 4795 Result.getValue(isLoad ? 1 : 0), 4796 &DeadNodes); 4797 removeFromWorkList(Op); 4798 DAG.DeleteNode(Op); 4799 return true; 4800 } 4801 } 4802 } 4803 4804 return false; 4805} 4806 4807/// InferAlignment - If we can infer some alignment information from this 4808/// pointer, return it. 4809static unsigned InferAlignment(SDValue Ptr, SelectionDAG &DAG) { 4810 // If this is a direct reference to a stack slot, use information about the 4811 // stack slot's alignment. 4812 int FrameIdx = 1 << 31; 4813 int64_t FrameOffset = 0; 4814 if (FrameIndexSDNode *FI = dyn_cast<FrameIndexSDNode>(Ptr)) { 4815 FrameIdx = FI->getIndex(); 4816 } else if (Ptr.getOpcode() == ISD::ADD && 4817 isa<ConstantSDNode>(Ptr.getOperand(1)) && 4818 isa<FrameIndexSDNode>(Ptr.getOperand(0))) { 4819 FrameIdx = cast<FrameIndexSDNode>(Ptr.getOperand(0))->getIndex(); 4820 FrameOffset = Ptr.getConstantOperandVal(1); 4821 } 4822 4823 if (FrameIdx != (1 << 31)) { 4824 // FIXME: Handle FI+CST. 4825 const MachineFrameInfo &MFI = *DAG.getMachineFunction().getFrameInfo(); 4826 if (MFI.isFixedObjectIndex(FrameIdx)) { 4827 int64_t ObjectOffset = MFI.getObjectOffset(FrameIdx) + FrameOffset; 4828 4829 // The alignment of the frame index can be determined from its offset from 4830 // the incoming frame position. If the frame object is at offset 32 and 4831 // the stack is guaranteed to be 16-byte aligned, then we know that the 4832 // object is 16-byte aligned. 4833 unsigned StackAlign = DAG.getTarget().getFrameInfo()->getStackAlignment(); 4834 unsigned Align = MinAlign(ObjectOffset, StackAlign); 4835 4836 // Finally, the frame object itself may have a known alignment. Factor 4837 // the alignment + offset into a new alignment. For example, if we know 4838 // the FI is 8 byte aligned, but the pointer is 4 off, we really have a 4839 // 4-byte alignment of the resultant pointer. Likewise align 4 + 4-byte 4840 // offset = 4-byte alignment, align 4 + 1-byte offset = align 1, etc. 4841 unsigned FIInfoAlign = MinAlign(MFI.getObjectAlignment(FrameIdx), 4842 FrameOffset); 4843 return std::max(Align, FIInfoAlign); 4844 } 4845 } 4846 4847 return 0; 4848} 4849 4850SDValue DAGCombiner::visitLOAD(SDNode *N) { 4851 LoadSDNode *LD = cast<LoadSDNode>(N); 4852 SDValue Chain = LD->getChain(); 4853 SDValue Ptr = LD->getBasePtr(); 4854 4855 // Try to infer better alignment information than the load already has. 4856 if (OptLevel != CodeGenOpt::None && LD->isUnindexed()) { 4857 if (unsigned Align = InferAlignment(Ptr, DAG)) { 4858 if (Align > LD->getAlignment()) 4859 return DAG.getExtLoad(LD->getExtensionType(), N->getDebugLoc(), 4860 LD->getValueType(0), 4861 Chain, Ptr, LD->getSrcValue(), 4862 LD->getSrcValueOffset(), LD->getMemoryVT(), 4863 LD->isVolatile(), Align); 4864 } 4865 } 4866 4867 // If load is not volatile and there are no uses of the loaded value (and 4868 // the updated indexed value in case of indexed loads), change uses of the 4869 // chain value into uses of the chain input (i.e. delete the dead load). 4870 if (!LD->isVolatile()) { 4871 if (N->getValueType(1) == MVT::Other) { 4872 // Unindexed loads. 4873 if (N->hasNUsesOfValue(0, 0)) { 4874 // It's not safe to use the two value CombineTo variant here. e.g. 4875 // v1, chain2 = load chain1, loc 4876 // v2, chain3 = load chain2, loc 4877 // v3 = add v2, c 4878 // Now we replace use of chain2 with chain1. This makes the second load 4879 // isomorphic to the one we are deleting, and thus makes this load live. 4880 DEBUG(errs() << "\nReplacing.6 "; 4881 N->dump(&DAG); 4882 errs() << "\nWith chain: "; 4883 Chain.getNode()->dump(&DAG); 4884 errs() << "\n"); 4885 WorkListRemover DeadNodes(*this); 4886 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), Chain, &DeadNodes); 4887 4888 if (N->use_empty()) { 4889 removeFromWorkList(N); 4890 DAG.DeleteNode(N); 4891 } 4892 4893 return SDValue(N, 0); // Return N so it doesn't get rechecked! 4894 } 4895 } else { 4896 // Indexed loads. 4897 assert(N->getValueType(2) == MVT::Other && "Malformed indexed loads?"); 4898 if (N->hasNUsesOfValue(0, 0) && N->hasNUsesOfValue(0, 1)) { 4899 SDValue Undef = DAG.getUNDEF(N->getValueType(0)); 4900 DEBUG(errs() << "\nReplacing.6 "; 4901 N->dump(&DAG); 4902 errs() << "\nWith: "; 4903 Undef.getNode()->dump(&DAG); 4904 errs() << " and 2 other values\n"); 4905 WorkListRemover DeadNodes(*this); 4906 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Undef, &DeadNodes); 4907 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), 4908 DAG.getUNDEF(N->getValueType(1)), 4909 &DeadNodes); 4910 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 2), Chain, &DeadNodes); 4911 removeFromWorkList(N); 4912 DAG.DeleteNode(N); 4913 return SDValue(N, 0); // Return N so it doesn't get rechecked! 4914 } 4915 } 4916 } 4917 4918 // If this load is directly stored, replace the load value with the stored 4919 // value. 4920 // TODO: Handle store large -> read small portion. 4921 // TODO: Handle TRUNCSTORE/LOADEXT 4922 if (LD->getExtensionType() == ISD::NON_EXTLOAD && 4923 !LD->isVolatile()) { 4924 if (ISD::isNON_TRUNCStore(Chain.getNode())) { 4925 StoreSDNode *PrevST = cast<StoreSDNode>(Chain); 4926 if (PrevST->getBasePtr() == Ptr && 4927 PrevST->getValue().getValueType() == N->getValueType(0)) 4928 return CombineTo(N, Chain.getOperand(1), Chain); 4929 } 4930 } 4931 4932 if (CombinerAA) { 4933 // Walk up chain skipping non-aliasing memory nodes. 4934 SDValue BetterChain = FindBetterChain(N, Chain); 4935 4936 // If there is a better chain. 4937 if (Chain != BetterChain) { 4938 SDValue ReplLoad; 4939 4940 // Replace the chain to void dependency. 4941 if (LD->getExtensionType() == ISD::NON_EXTLOAD) { 4942 ReplLoad = DAG.getLoad(N->getValueType(0), LD->getDebugLoc(), 4943 BetterChain, Ptr, 4944 LD->getSrcValue(), LD->getSrcValueOffset(), 4945 LD->isVolatile(), LD->getAlignment()); 4946 } else { 4947 ReplLoad = DAG.getExtLoad(LD->getExtensionType(), LD->getDebugLoc(), 4948 LD->getValueType(0), 4949 BetterChain, Ptr, LD->getSrcValue(), 4950 LD->getSrcValueOffset(), 4951 LD->getMemoryVT(), 4952 LD->isVolatile(), 4953 LD->getAlignment()); 4954 } 4955 4956 // Create token factor to keep old chain connected. 4957 SDValue Token = DAG.getNode(ISD::TokenFactor, N->getDebugLoc(), 4958 MVT::Other, Chain, ReplLoad.getValue(1)); 4959 4960 // Make sure the new and old chains are cleaned up. 4961 AddToWorkList(Token.getNode()); 4962 4963 // Replace uses with load result and token factor. Don't add users 4964 // to work list. 4965 return CombineTo(N, ReplLoad.getValue(0), Token, false); 4966 } 4967 } 4968 4969 // Try transforming N to an indexed load. 4970 if (CombineToPreIndexedLoadStore(N) || CombineToPostIndexedLoadStore(N)) 4971 return SDValue(N, 0); 4972 4973 return SDValue(); 4974} 4975 4976 4977/// ReduceLoadOpStoreWidth - Look for sequence of load / op / store where op is 4978/// one of 'or', 'xor', and 'and' of immediates. If 'op' is only touching some 4979/// of the loaded bits, try narrowing the load and store if it would end up 4980/// being a win for performance or code size. 4981SDValue DAGCombiner::ReduceLoadOpStoreWidth(SDNode *N) { 4982 StoreSDNode *ST = cast<StoreSDNode>(N); 4983 if (ST->isVolatile()) 4984 return SDValue(); 4985 4986 SDValue Chain = ST->getChain(); 4987 SDValue Value = ST->getValue(); 4988 SDValue Ptr = ST->getBasePtr(); 4989 EVT VT = Value.getValueType(); 4990 4991 if (ST->isTruncatingStore() || VT.isVector() || !Value.hasOneUse()) 4992 return SDValue(); 4993 4994 unsigned Opc = Value.getOpcode(); 4995 if ((Opc != ISD::OR && Opc != ISD::XOR && Opc != ISD::AND) || 4996 Value.getOperand(1).getOpcode() != ISD::Constant) 4997 return SDValue(); 4998 4999 SDValue N0 = Value.getOperand(0); 5000 if (ISD::isNormalLoad(N0.getNode()) && N0.hasOneUse()) { 5001 LoadSDNode *LD = cast<LoadSDNode>(N0); 5002 if (LD->getBasePtr() != Ptr) 5003 return SDValue(); 5004 5005 // Find the type to narrow it the load / op / store to. 5006 SDValue N1 = Value.getOperand(1); 5007 unsigned BitWidth = N1.getValueSizeInBits(); 5008 APInt Imm = cast<ConstantSDNode>(N1)->getAPIntValue(); 5009 if (Opc == ISD::AND) 5010 Imm ^= APInt::getAllOnesValue(BitWidth); 5011 if (Imm == 0 || Imm.isAllOnesValue()) 5012 return SDValue(); 5013 unsigned ShAmt = Imm.countTrailingZeros(); 5014 unsigned MSB = BitWidth - Imm.countLeadingZeros() - 1; 5015 unsigned NewBW = NextPowerOf2(MSB - ShAmt); 5016 EVT NewVT = EVT::getIntegerVT(*DAG.getContext(), NewBW); 5017 while (NewBW < BitWidth && 5018 !(TLI.isOperationLegalOrCustom(Opc, NewVT) && 5019 TLI.isNarrowingProfitable(VT, NewVT))) { 5020 NewBW = NextPowerOf2(NewBW); 5021 NewVT = EVT::getIntegerVT(*DAG.getContext(), NewBW); 5022 } 5023 if (NewBW >= BitWidth) 5024 return SDValue(); 5025 5026 // If the lsb changed does not start at the type bitwidth boundary, 5027 // start at the previous one. 5028 if (ShAmt % NewBW) 5029 ShAmt = (((ShAmt + NewBW - 1) / NewBW) * NewBW) - NewBW; 5030 APInt Mask = APInt::getBitsSet(BitWidth, ShAmt, ShAmt + NewBW); 5031 if ((Imm & Mask) == Imm) { 5032 APInt NewImm = (Imm & Mask).lshr(ShAmt).trunc(NewBW); 5033 if (Opc == ISD::AND) 5034 NewImm ^= APInt::getAllOnesValue(NewBW); 5035 uint64_t PtrOff = ShAmt / 8; 5036 // For big endian targets, we need to adjust the offset to the pointer to 5037 // load the correct bytes. 5038 if (TLI.isBigEndian()) 5039 PtrOff = (BitWidth + 7 - NewBW) / 8 - PtrOff; 5040 5041 unsigned NewAlign = MinAlign(LD->getAlignment(), PtrOff); 5042 if (NewAlign < 5043 TLI.getTargetData()->getABITypeAlignment(NewVT.getTypeForEVT(*DAG.getContext()))) 5044 return SDValue(); 5045 5046 SDValue NewPtr = DAG.getNode(ISD::ADD, LD->getDebugLoc(), 5047 Ptr.getValueType(), Ptr, 5048 DAG.getConstant(PtrOff, Ptr.getValueType())); 5049 SDValue NewLD = DAG.getLoad(NewVT, N0.getDebugLoc(), 5050 LD->getChain(), NewPtr, 5051 LD->getSrcValue(), LD->getSrcValueOffset(), 5052 LD->isVolatile(), NewAlign); 5053 SDValue NewVal = DAG.getNode(Opc, Value.getDebugLoc(), NewVT, NewLD, 5054 DAG.getConstant(NewImm, NewVT)); 5055 SDValue NewST = DAG.getStore(Chain, N->getDebugLoc(), 5056 NewVal, NewPtr, 5057 ST->getSrcValue(), ST->getSrcValueOffset(), 5058 false, NewAlign); 5059 5060 AddToWorkList(NewPtr.getNode()); 5061 AddToWorkList(NewLD.getNode()); 5062 AddToWorkList(NewVal.getNode()); 5063 WorkListRemover DeadNodes(*this); 5064 DAG.ReplaceAllUsesOfValueWith(N0.getValue(1), NewLD.getValue(1), 5065 &DeadNodes); 5066 ++OpsNarrowed; 5067 return NewST; 5068 } 5069 } 5070 5071 return SDValue(); 5072} 5073 5074SDValue DAGCombiner::visitSTORE(SDNode *N) { 5075 StoreSDNode *ST = cast<StoreSDNode>(N); 5076 SDValue Chain = ST->getChain(); 5077 SDValue Value = ST->getValue(); 5078 SDValue Ptr = ST->getBasePtr(); 5079 5080 // Try to infer better alignment information than the store already has. 5081 if (OptLevel != CodeGenOpt::None && ST->isUnindexed()) { 5082 if (unsigned Align = InferAlignment(Ptr, DAG)) { 5083 if (Align > ST->getAlignment()) 5084 return DAG.getTruncStore(Chain, N->getDebugLoc(), Value, 5085 Ptr, ST->getSrcValue(), 5086 ST->getSrcValueOffset(), ST->getMemoryVT(), 5087 ST->isVolatile(), Align); 5088 } 5089 } 5090 5091 // If this is a store of a bit convert, store the input value if the 5092 // resultant store does not need a higher alignment than the original. 5093 if (Value.getOpcode() == ISD::BIT_CONVERT && !ST->isTruncatingStore() && 5094 ST->isUnindexed()) { 5095 unsigned OrigAlign = ST->getAlignment(); 5096 EVT SVT = Value.getOperand(0).getValueType(); 5097 unsigned Align = TLI.getTargetData()-> 5098 getABITypeAlignment(SVT.getTypeForEVT(*DAG.getContext())); 5099 if (Align <= OrigAlign && 5100 ((!LegalOperations && !ST->isVolatile()) || 5101 TLI.isOperationLegalOrCustom(ISD::STORE, SVT))) 5102 return DAG.getStore(Chain, N->getDebugLoc(), Value.getOperand(0), 5103 Ptr, ST->getSrcValue(), 5104 ST->getSrcValueOffset(), ST->isVolatile(), OrigAlign); 5105 } 5106 5107 // Turn 'store float 1.0, Ptr' -> 'store int 0x12345678, Ptr' 5108 if (ConstantFPSDNode *CFP = dyn_cast<ConstantFPSDNode>(Value)) { 5109 // NOTE: If the original store is volatile, this transform must not increase 5110 // the number of stores. For example, on x86-32 an f64 can be stored in one 5111 // processor operation but an i64 (which is not legal) requires two. So the 5112 // transform should not be done in this case. 5113 if (Value.getOpcode() != ISD::TargetConstantFP) { 5114 SDValue Tmp; 5115 switch (CFP->getValueType(0).getSimpleVT().SimpleTy) { 5116 default: llvm_unreachable("Unknown FP type"); 5117 case MVT::f80: // We don't do this for these yet. 5118 case MVT::f128: 5119 case MVT::ppcf128: 5120 break; 5121 case MVT::f32: 5122 if (((TLI.isTypeLegal(MVT::i32) || !LegalTypes) && !LegalOperations && 5123 !ST->isVolatile()) || 5124 TLI.isOperationLegalOrCustom(ISD::STORE, MVT::i32)) { 5125 Tmp = DAG.getConstant((uint32_t)CFP->getValueAPF(). 5126 bitcastToAPInt().getZExtValue(), MVT::i32); 5127 return DAG.getStore(Chain, N->getDebugLoc(), Tmp, 5128 Ptr, ST->getSrcValue(), 5129 ST->getSrcValueOffset(), ST->isVolatile(), 5130 ST->getAlignment()); 5131 } 5132 break; 5133 case MVT::f64: 5134 if (((TLI.isTypeLegal(MVT::i64) || !LegalTypes) && !LegalOperations && 5135 !ST->isVolatile()) || 5136 TLI.isOperationLegalOrCustom(ISD::STORE, MVT::i64)) { 5137 Tmp = DAG.getConstant(CFP->getValueAPF().bitcastToAPInt(). 5138 getZExtValue(), MVT::i64); 5139 return DAG.getStore(Chain, N->getDebugLoc(), Tmp, 5140 Ptr, ST->getSrcValue(), 5141 ST->getSrcValueOffset(), ST->isVolatile(), 5142 ST->getAlignment()); 5143 } else if (!ST->isVolatile() && 5144 TLI.isOperationLegalOrCustom(ISD::STORE, MVT::i32)) { 5145 // Many FP stores are not made apparent until after legalize, e.g. for 5146 // argument passing. Since this is so common, custom legalize the 5147 // 64-bit integer store into two 32-bit stores. 5148 uint64_t Val = CFP->getValueAPF().bitcastToAPInt().getZExtValue(); 5149 SDValue Lo = DAG.getConstant(Val & 0xFFFFFFFF, MVT::i32); 5150 SDValue Hi = DAG.getConstant(Val >> 32, MVT::i32); 5151 if (TLI.isBigEndian()) std::swap(Lo, Hi); 5152 5153 int SVOffset = ST->getSrcValueOffset(); 5154 unsigned Alignment = ST->getAlignment(); 5155 bool isVolatile = ST->isVolatile(); 5156 5157 SDValue St0 = DAG.getStore(Chain, ST->getDebugLoc(), Lo, 5158 Ptr, ST->getSrcValue(), 5159 ST->getSrcValueOffset(), 5160 isVolatile, ST->getAlignment()); 5161 Ptr = DAG.getNode(ISD::ADD, N->getDebugLoc(), Ptr.getValueType(), Ptr, 5162 DAG.getConstant(4, Ptr.getValueType())); 5163 SVOffset += 4; 5164 Alignment = MinAlign(Alignment, 4U); 5165 SDValue St1 = DAG.getStore(Chain, ST->getDebugLoc(), Hi, 5166 Ptr, ST->getSrcValue(), 5167 SVOffset, isVolatile, Alignment); 5168 return DAG.getNode(ISD::TokenFactor, N->getDebugLoc(), MVT::Other, 5169 St0, St1); 5170 } 5171 5172 break; 5173 } 5174 } 5175 } 5176 5177 if (CombinerAA) { 5178 // Walk up chain skipping non-aliasing memory nodes. 5179 SDValue BetterChain = FindBetterChain(N, Chain); 5180 5181 // If there is a better chain. 5182 if (Chain != BetterChain) { 5183 SDValue ReplStore; 5184 5185 // Replace the chain to avoid dependency. 5186 if (ST->isTruncatingStore()) { 5187 ReplStore = DAG.getTruncStore(BetterChain, N->getDebugLoc(), Value, Ptr, 5188 ST->getSrcValue(),ST->getSrcValueOffset(), 5189 ST->getMemoryVT(), 5190 ST->isVolatile(), ST->getAlignment()); 5191 } else { 5192 ReplStore = DAG.getStore(BetterChain, N->getDebugLoc(), Value, Ptr, 5193 ST->getSrcValue(), ST->getSrcValueOffset(), 5194 ST->isVolatile(), ST->getAlignment()); 5195 } 5196 5197 // Create token to keep both nodes around. 5198 SDValue Token = DAG.getNode(ISD::TokenFactor, N->getDebugLoc(), 5199 MVT::Other, Chain, ReplStore); 5200 5201 // Make sure the new and old chains are cleaned up. 5202 AddToWorkList(Token.getNode()); 5203 5204 // Don't add users to work list. 5205 return CombineTo(N, Token, false); 5206 } 5207 } 5208 5209 // Try transforming N to an indexed store. 5210 if (CombineToPreIndexedLoadStore(N) || CombineToPostIndexedLoadStore(N)) 5211 return SDValue(N, 0); 5212 5213 // FIXME: is there such a thing as a truncating indexed store? 5214 if (ST->isTruncatingStore() && ST->isUnindexed() && 5215 Value.getValueType().isInteger()) { 5216 // See if we can simplify the input to this truncstore with knowledge that 5217 // only the low bits are being used. For example: 5218 // "truncstore (or (shl x, 8), y), i8" -> "truncstore y, i8" 5219 SDValue Shorter = 5220 GetDemandedBits(Value, 5221 APInt::getLowBitsSet(Value.getValueSizeInBits(), 5222 ST->getMemoryVT().getSizeInBits())); 5223 AddToWorkList(Value.getNode()); 5224 if (Shorter.getNode()) 5225 return DAG.getTruncStore(Chain, N->getDebugLoc(), Shorter, 5226 Ptr, ST->getSrcValue(), 5227 ST->getSrcValueOffset(), ST->getMemoryVT(), 5228 ST->isVolatile(), ST->getAlignment()); 5229 5230 // Otherwise, see if we can simplify the operation with 5231 // SimplifyDemandedBits, which only works if the value has a single use. 5232 if (SimplifyDemandedBits(Value, 5233 APInt::getLowBitsSet( 5234 Value.getValueSizeInBits(), 5235 ST->getMemoryVT().getSizeInBits()))) 5236 return SDValue(N, 0); 5237 } 5238 5239 // If this is a load followed by a store to the same location, then the store 5240 // is dead/noop. 5241 if (LoadSDNode *Ld = dyn_cast<LoadSDNode>(Value)) { 5242 if (Ld->getBasePtr() == Ptr && ST->getMemoryVT() == Ld->getMemoryVT() && 5243 ST->isUnindexed() && !ST->isVolatile() && 5244 // There can't be any side effects between the load and store, such as 5245 // a call or store. 5246 Chain.reachesChainWithoutSideEffects(SDValue(Ld, 1))) { 5247 // The store is dead, remove it. 5248 return Chain; 5249 } 5250 } 5251 5252 // If this is an FP_ROUND or TRUNC followed by a store, fold this into a 5253 // truncating store. We can do this even if this is already a truncstore. 5254 if ((Value.getOpcode() == ISD::FP_ROUND || Value.getOpcode() == ISD::TRUNCATE) 5255 && Value.getNode()->hasOneUse() && ST->isUnindexed() && 5256 TLI.isTruncStoreLegal(Value.getOperand(0).getValueType(), 5257 ST->getMemoryVT())) { 5258 return DAG.getTruncStore(Chain, N->getDebugLoc(), Value.getOperand(0), 5259 Ptr, ST->getSrcValue(), 5260 ST->getSrcValueOffset(), ST->getMemoryVT(), 5261 ST->isVolatile(), ST->getAlignment()); 5262 } 5263 5264 return ReduceLoadOpStoreWidth(N); 5265} 5266 5267SDValue DAGCombiner::visitINSERT_VECTOR_ELT(SDNode *N) { 5268 SDValue InVec = N->getOperand(0); 5269 SDValue InVal = N->getOperand(1); 5270 SDValue EltNo = N->getOperand(2); 5271 5272 // If the invec is a BUILD_VECTOR and if EltNo is a constant, build a new 5273 // vector with the inserted element. 5274 if (InVec.getOpcode() == ISD::BUILD_VECTOR && isa<ConstantSDNode>(EltNo)) { 5275 unsigned Elt = cast<ConstantSDNode>(EltNo)->getZExtValue(); 5276 SmallVector<SDValue, 8> Ops(InVec.getNode()->op_begin(), 5277 InVec.getNode()->op_end()); 5278 if (Elt < Ops.size()) 5279 Ops[Elt] = InVal; 5280 return DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(), 5281 InVec.getValueType(), &Ops[0], Ops.size()); 5282 } 5283 // If the invec is an UNDEF and if EltNo is a constant, create a new 5284 // BUILD_VECTOR with undef elements and the inserted element. 5285 if (!LegalOperations && InVec.getOpcode() == ISD::UNDEF && 5286 isa<ConstantSDNode>(EltNo)) { 5287 EVT VT = InVec.getValueType(); 5288 EVT EltVT = VT.getVectorElementType(); 5289 unsigned NElts = VT.getVectorNumElements(); 5290 SmallVector<SDValue, 8> Ops(NElts, DAG.getUNDEF(EltVT)); 5291 5292 unsigned Elt = cast<ConstantSDNode>(EltNo)->getZExtValue(); 5293 if (Elt < Ops.size()) 5294 Ops[Elt] = InVal; 5295 return DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(), 5296 InVec.getValueType(), &Ops[0], Ops.size()); 5297 } 5298 return SDValue(); 5299} 5300 5301SDValue DAGCombiner::visitEXTRACT_VECTOR_ELT(SDNode *N) { 5302 // (vextract (scalar_to_vector val, 0) -> val 5303 SDValue InVec = N->getOperand(0); 5304 5305 if (InVec.getOpcode() == ISD::SCALAR_TO_VECTOR) { 5306 // If the operand is wider than the vector element type then it is implicitly 5307 // truncated. Make that explicit here. 5308 EVT EltVT = InVec.getValueType().getVectorElementType(); 5309 SDValue InOp = InVec.getOperand(0); 5310 if (InOp.getValueType() != EltVT) 5311 return DAG.getNode(ISD::TRUNCATE, InVec.getDebugLoc(), EltVT, InOp); 5312 return InOp; 5313 } 5314 5315 // Perform only after legalization to ensure build_vector / vector_shuffle 5316 // optimizations have already been done. 5317 if (!LegalOperations) return SDValue(); 5318 5319 // (vextract (v4f32 load $addr), c) -> (f32 load $addr+c*size) 5320 // (vextract (v4f32 s2v (f32 load $addr)), c) -> (f32 load $addr+c*size) 5321 // (vextract (v4f32 shuffle (load $addr), <1,u,u,u>), 0) -> (f32 load $addr) 5322 SDValue EltNo = N->getOperand(1); 5323 5324 if (isa<ConstantSDNode>(EltNo)) { 5325 unsigned Elt = cast<ConstantSDNode>(EltNo)->getZExtValue(); 5326 bool NewLoad = false; 5327 bool BCNumEltsChanged = false; 5328 EVT VT = InVec.getValueType(); 5329 EVT ExtVT = VT.getVectorElementType(); 5330 EVT LVT = ExtVT; 5331 5332 if (InVec.getOpcode() == ISD::BIT_CONVERT) { 5333 EVT BCVT = InVec.getOperand(0).getValueType(); 5334 if (!BCVT.isVector() || ExtVT.bitsGT(BCVT.getVectorElementType())) 5335 return SDValue(); 5336 if (VT.getVectorNumElements() != BCVT.getVectorNumElements()) 5337 BCNumEltsChanged = true; 5338 InVec = InVec.getOperand(0); 5339 ExtVT = BCVT.getVectorElementType(); 5340 NewLoad = true; 5341 } 5342 5343 LoadSDNode *LN0 = NULL; 5344 const ShuffleVectorSDNode *SVN = NULL; 5345 if (ISD::isNormalLoad(InVec.getNode())) { 5346 LN0 = cast<LoadSDNode>(InVec); 5347 } else if (InVec.getOpcode() == ISD::SCALAR_TO_VECTOR && 5348 InVec.getOperand(0).getValueType() == ExtVT && 5349 ISD::isNormalLoad(InVec.getOperand(0).getNode())) { 5350 LN0 = cast<LoadSDNode>(InVec.getOperand(0)); 5351 } else if ((SVN = dyn_cast<ShuffleVectorSDNode>(InVec))) { 5352 // (vextract (vector_shuffle (load $addr), v2, <1, u, u, u>), 1) 5353 // => 5354 // (load $addr+1*size) 5355 5356 // If the bit convert changed the number of elements, it is unsafe 5357 // to examine the mask. 5358 if (BCNumEltsChanged) 5359 return SDValue(); 5360 5361 // Select the input vector, guarding against out of range extract vector. 5362 unsigned NumElems = VT.getVectorNumElements(); 5363 int Idx = (Elt > NumElems) ? -1 : SVN->getMaskElt(Elt); 5364 InVec = (Idx < (int)NumElems) ? InVec.getOperand(0) : InVec.getOperand(1); 5365 5366 if (InVec.getOpcode() == ISD::BIT_CONVERT) 5367 InVec = InVec.getOperand(0); 5368 if (ISD::isNormalLoad(InVec.getNode())) { 5369 LN0 = cast<LoadSDNode>(InVec); 5370 Elt = (Idx < (int)NumElems) ? Idx : Idx - NumElems; 5371 } 5372 } 5373 5374 if (!LN0 || !LN0->hasOneUse() || LN0->isVolatile()) 5375 return SDValue(); 5376 5377 unsigned Align = LN0->getAlignment(); 5378 if (NewLoad) { 5379 // Check the resultant load doesn't need a higher alignment than the 5380 // original load. 5381 unsigned NewAlign = 5382 TLI.getTargetData()->getABITypeAlignment(LVT.getTypeForEVT(*DAG.getContext())); 5383 5384 if (NewAlign > Align || !TLI.isOperationLegalOrCustom(ISD::LOAD, LVT)) 5385 return SDValue(); 5386 5387 Align = NewAlign; 5388 } 5389 5390 SDValue NewPtr = LN0->getBasePtr(); 5391 if (Elt) { 5392 unsigned PtrOff = LVT.getSizeInBits() * Elt / 8; 5393 EVT PtrType = NewPtr.getValueType(); 5394 if (TLI.isBigEndian()) 5395 PtrOff = VT.getSizeInBits() / 8 - PtrOff; 5396 NewPtr = DAG.getNode(ISD::ADD, N->getDebugLoc(), PtrType, NewPtr, 5397 DAG.getConstant(PtrOff, PtrType)); 5398 } 5399 5400 return DAG.getLoad(LVT, N->getDebugLoc(), LN0->getChain(), NewPtr, 5401 LN0->getSrcValue(), LN0->getSrcValueOffset(), 5402 LN0->isVolatile(), Align); 5403 } 5404 5405 return SDValue(); 5406} 5407 5408SDValue DAGCombiner::visitBUILD_VECTOR(SDNode *N) { 5409 unsigned NumInScalars = N->getNumOperands(); 5410 EVT VT = N->getValueType(0); 5411 5412 // Check to see if this is a BUILD_VECTOR of a bunch of EXTRACT_VECTOR_ELT 5413 // operations. If so, and if the EXTRACT_VECTOR_ELT vector inputs come from 5414 // at most two distinct vectors, turn this into a shuffle node. 5415 SDValue VecIn1, VecIn2; 5416 for (unsigned i = 0; i != NumInScalars; ++i) { 5417 // Ignore undef inputs. 5418 if (N->getOperand(i).getOpcode() == ISD::UNDEF) continue; 5419 5420 // If this input is something other than a EXTRACT_VECTOR_ELT with a 5421 // constant index, bail out. 5422 if (N->getOperand(i).getOpcode() != ISD::EXTRACT_VECTOR_ELT || 5423 !isa<ConstantSDNode>(N->getOperand(i).getOperand(1))) { 5424 VecIn1 = VecIn2 = SDValue(0, 0); 5425 break; 5426 } 5427 5428 // If the input vector type disagrees with the result of the build_vector, 5429 // we can't make a shuffle. 5430 SDValue ExtractedFromVec = N->getOperand(i).getOperand(0); 5431 if (ExtractedFromVec.getValueType() != VT) { 5432 VecIn1 = VecIn2 = SDValue(0, 0); 5433 break; 5434 } 5435 5436 // Otherwise, remember this. We allow up to two distinct input vectors. 5437 if (ExtractedFromVec == VecIn1 || ExtractedFromVec == VecIn2) 5438 continue; 5439 5440 if (VecIn1.getNode() == 0) { 5441 VecIn1 = ExtractedFromVec; 5442 } else if (VecIn2.getNode() == 0) { 5443 VecIn2 = ExtractedFromVec; 5444 } else { 5445 // Too many inputs. 5446 VecIn1 = VecIn2 = SDValue(0, 0); 5447 break; 5448 } 5449 } 5450 5451 // If everything is good, we can make a shuffle operation. 5452 if (VecIn1.getNode()) { 5453 SmallVector<int, 8> Mask; 5454 for (unsigned i = 0; i != NumInScalars; ++i) { 5455 if (N->getOperand(i).getOpcode() == ISD::UNDEF) { 5456 Mask.push_back(-1); 5457 continue; 5458 } 5459 5460 // If extracting from the first vector, just use the index directly. 5461 SDValue Extract = N->getOperand(i); 5462 SDValue ExtVal = Extract.getOperand(1); 5463 if (Extract.getOperand(0) == VecIn1) { 5464 unsigned ExtIndex = cast<ConstantSDNode>(ExtVal)->getZExtValue(); 5465 if (ExtIndex > VT.getVectorNumElements()) 5466 return SDValue(); 5467 5468 Mask.push_back(ExtIndex); 5469 continue; 5470 } 5471 5472 // Otherwise, use InIdx + VecSize 5473 unsigned Idx = cast<ConstantSDNode>(ExtVal)->getZExtValue(); 5474 Mask.push_back(Idx+NumInScalars); 5475 } 5476 5477 // Add count and size info. 5478 if (!TLI.isTypeLegal(VT) && LegalTypes) 5479 return SDValue(); 5480 5481 // Return the new VECTOR_SHUFFLE node. 5482 SDValue Ops[2]; 5483 Ops[0] = VecIn1; 5484 Ops[1] = VecIn2.getNode() ? VecIn2 : DAG.getUNDEF(VT); 5485 return DAG.getVectorShuffle(VT, N->getDebugLoc(), Ops[0], Ops[1], &Mask[0]); 5486 } 5487 5488 return SDValue(); 5489} 5490 5491SDValue DAGCombiner::visitCONCAT_VECTORS(SDNode *N) { 5492 // TODO: Check to see if this is a CONCAT_VECTORS of a bunch of 5493 // EXTRACT_SUBVECTOR operations. If so, and if the EXTRACT_SUBVECTOR vector 5494 // inputs come from at most two distinct vectors, turn this into a shuffle 5495 // node. 5496 5497 // If we only have one input vector, we don't need to do any concatenation. 5498 if (N->getNumOperands() == 1) 5499 return N->getOperand(0); 5500 5501 return SDValue(); 5502} 5503 5504SDValue DAGCombiner::visitVECTOR_SHUFFLE(SDNode *N) { 5505 return SDValue(); 5506 5507 EVT VT = N->getValueType(0); 5508 unsigned NumElts = VT.getVectorNumElements(); 5509 5510 SDValue N0 = N->getOperand(0); 5511 5512 assert(N0.getValueType().getVectorNumElements() == NumElts && 5513 "Vector shuffle must be normalized in DAG"); 5514 5515 // FIXME: implement canonicalizations from DAG.getVectorShuffle() 5516 5517 // If it is a splat, check if the argument vector is a build_vector with 5518 // all scalar elements the same. 5519 if (cast<ShuffleVectorSDNode>(N)->isSplat()) { 5520 SDNode *V = N0.getNode(); 5521 5522 5523 // If this is a bit convert that changes the element type of the vector but 5524 // not the number of vector elements, look through it. Be careful not to 5525 // look though conversions that change things like v4f32 to v2f64. 5526 if (V->getOpcode() == ISD::BIT_CONVERT) { 5527 SDValue ConvInput = V->getOperand(0); 5528 if (ConvInput.getValueType().isVector() && 5529 ConvInput.getValueType().getVectorNumElements() == NumElts) 5530 V = ConvInput.getNode(); 5531 } 5532 5533 if (V->getOpcode() == ISD::BUILD_VECTOR) { 5534 unsigned NumElems = V->getNumOperands(); 5535 unsigned BaseIdx = cast<ShuffleVectorSDNode>(N)->getSplatIndex(); 5536 if (NumElems > BaseIdx) { 5537 SDValue Base; 5538 bool AllSame = true; 5539 for (unsigned i = 0; i != NumElems; ++i) { 5540 if (V->getOperand(i).getOpcode() != ISD::UNDEF) { 5541 Base = V->getOperand(i); 5542 break; 5543 } 5544 } 5545 // Splat of <u, u, u, u>, return <u, u, u, u> 5546 if (!Base.getNode()) 5547 return N0; 5548 for (unsigned i = 0; i != NumElems; ++i) { 5549 if (V->getOperand(i) != Base) { 5550 AllSame = false; 5551 break; 5552 } 5553 } 5554 // Splat of <x, x, x, x>, return <x, x, x, x> 5555 if (AllSame) 5556 return N0; 5557 } 5558 } 5559 } 5560 return SDValue(); 5561} 5562 5563/// XformToShuffleWithZero - Returns a vector_shuffle if it able to transform 5564/// an AND to a vector_shuffle with the destination vector and a zero vector. 5565/// e.g. AND V, <0xffffffff, 0, 0xffffffff, 0>. ==> 5566/// vector_shuffle V, Zero, <0, 4, 2, 4> 5567SDValue DAGCombiner::XformToShuffleWithZero(SDNode *N) { 5568 EVT VT = N->getValueType(0); 5569 DebugLoc dl = N->getDebugLoc(); 5570 SDValue LHS = N->getOperand(0); 5571 SDValue RHS = N->getOperand(1); 5572 if (N->getOpcode() == ISD::AND) { 5573 if (RHS.getOpcode() == ISD::BIT_CONVERT) 5574 RHS = RHS.getOperand(0); 5575 if (RHS.getOpcode() == ISD::BUILD_VECTOR) { 5576 SmallVector<int, 8> Indices; 5577 unsigned NumElts = RHS.getNumOperands(); 5578 for (unsigned i = 0; i != NumElts; ++i) { 5579 SDValue Elt = RHS.getOperand(i); 5580 if (!isa<ConstantSDNode>(Elt)) 5581 return SDValue(); 5582 else if (cast<ConstantSDNode>(Elt)->isAllOnesValue()) 5583 Indices.push_back(i); 5584 else if (cast<ConstantSDNode>(Elt)->isNullValue()) 5585 Indices.push_back(NumElts); 5586 else 5587 return SDValue(); 5588 } 5589 5590 // Let's see if the target supports this vector_shuffle. 5591 EVT RVT = RHS.getValueType(); 5592 if (!TLI.isVectorClearMaskLegal(Indices, RVT)) 5593 return SDValue(); 5594 5595 // Return the new VECTOR_SHUFFLE node. 5596 EVT EltVT = RVT.getVectorElementType(); 5597 SmallVector<SDValue,8> ZeroOps(RVT.getVectorNumElements(), 5598 DAG.getConstant(0, EltVT)); 5599 SDValue Zero = DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(), 5600 RVT, &ZeroOps[0], ZeroOps.size()); 5601 LHS = DAG.getNode(ISD::BIT_CONVERT, dl, RVT, LHS); 5602 SDValue Shuf = DAG.getVectorShuffle(RVT, dl, LHS, Zero, &Indices[0]); 5603 return DAG.getNode(ISD::BIT_CONVERT, dl, VT, Shuf); 5604 } 5605 } 5606 5607 return SDValue(); 5608} 5609 5610/// SimplifyVBinOp - Visit a binary vector operation, like ADD. 5611SDValue DAGCombiner::SimplifyVBinOp(SDNode *N) { 5612 // After legalize, the target may be depending on adds and other 5613 // binary ops to provide legal ways to construct constants or other 5614 // things. Simplifying them may result in a loss of legality. 5615 if (LegalOperations) return SDValue(); 5616 5617 EVT VT = N->getValueType(0); 5618 assert(VT.isVector() && "SimplifyVBinOp only works on vectors!"); 5619 5620 EVT EltType = VT.getVectorElementType(); 5621 SDValue LHS = N->getOperand(0); 5622 SDValue RHS = N->getOperand(1); 5623 SDValue Shuffle = XformToShuffleWithZero(N); 5624 if (Shuffle.getNode()) return Shuffle; 5625 5626 // If the LHS and RHS are BUILD_VECTOR nodes, see if we can constant fold 5627 // this operation. 5628 if (LHS.getOpcode() == ISD::BUILD_VECTOR && 5629 RHS.getOpcode() == ISD::BUILD_VECTOR) { 5630 SmallVector<SDValue, 8> Ops; 5631 for (unsigned i = 0, e = LHS.getNumOperands(); i != e; ++i) { 5632 SDValue LHSOp = LHS.getOperand(i); 5633 SDValue RHSOp = RHS.getOperand(i); 5634 // If these two elements can't be folded, bail out. 5635 if ((LHSOp.getOpcode() != ISD::UNDEF && 5636 LHSOp.getOpcode() != ISD::Constant && 5637 LHSOp.getOpcode() != ISD::ConstantFP) || 5638 (RHSOp.getOpcode() != ISD::UNDEF && 5639 RHSOp.getOpcode() != ISD::Constant && 5640 RHSOp.getOpcode() != ISD::ConstantFP)) 5641 break; 5642 5643 // Can't fold divide by zero. 5644 if (N->getOpcode() == ISD::SDIV || N->getOpcode() == ISD::UDIV || 5645 N->getOpcode() == ISD::FDIV) { 5646 if ((RHSOp.getOpcode() == ISD::Constant && 5647 cast<ConstantSDNode>(RHSOp.getNode())->isNullValue()) || 5648 (RHSOp.getOpcode() == ISD::ConstantFP && 5649 cast<ConstantFPSDNode>(RHSOp.getNode())->getValueAPF().isZero())) 5650 break; 5651 } 5652 5653 Ops.push_back(DAG.getNode(N->getOpcode(), LHS.getDebugLoc(), 5654 EltType, LHSOp, RHSOp)); 5655 AddToWorkList(Ops.back().getNode()); 5656 assert((Ops.back().getOpcode() == ISD::UNDEF || 5657 Ops.back().getOpcode() == ISD::Constant || 5658 Ops.back().getOpcode() == ISD::ConstantFP) && 5659 "Scalar binop didn't fold!"); 5660 } 5661 5662 if (Ops.size() == LHS.getNumOperands()) { 5663 EVT VT = LHS.getValueType(); 5664 return DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(), VT, 5665 &Ops[0], Ops.size()); 5666 } 5667 } 5668 5669 return SDValue(); 5670} 5671 5672SDValue DAGCombiner::SimplifySelect(DebugLoc DL, SDValue N0, 5673 SDValue N1, SDValue N2){ 5674 assert(N0.getOpcode() ==ISD::SETCC && "First argument must be a SetCC node!"); 5675 5676 SDValue SCC = SimplifySelectCC(DL, N0.getOperand(0), N0.getOperand(1), N1, N2, 5677 cast<CondCodeSDNode>(N0.getOperand(2))->get()); 5678 5679 // If we got a simplified select_cc node back from SimplifySelectCC, then 5680 // break it down into a new SETCC node, and a new SELECT node, and then return 5681 // the SELECT node, since we were called with a SELECT node. 5682 if (SCC.getNode()) { 5683 // Check to see if we got a select_cc back (to turn into setcc/select). 5684 // Otherwise, just return whatever node we got back, like fabs. 5685 if (SCC.getOpcode() == ISD::SELECT_CC) { 5686 SDValue SETCC = DAG.getNode(ISD::SETCC, N0.getDebugLoc(), 5687 N0.getValueType(), 5688 SCC.getOperand(0), SCC.getOperand(1), 5689 SCC.getOperand(4)); 5690 AddToWorkList(SETCC.getNode()); 5691 return DAG.getNode(ISD::SELECT, SCC.getDebugLoc(), SCC.getValueType(), 5692 SCC.getOperand(2), SCC.getOperand(3), SETCC); 5693 } 5694 5695 return SCC; 5696 } 5697 return SDValue(); 5698} 5699 5700/// SimplifySelectOps - Given a SELECT or a SELECT_CC node, where LHS and RHS 5701/// are the two values being selected between, see if we can simplify the 5702/// select. Callers of this should assume that TheSelect is deleted if this 5703/// returns true. As such, they should return the appropriate thing (e.g. the 5704/// node) back to the top-level of the DAG combiner loop to avoid it being 5705/// looked at. 5706bool DAGCombiner::SimplifySelectOps(SDNode *TheSelect, SDValue LHS, 5707 SDValue RHS) { 5708 5709 // If this is a select from two identical things, try to pull the operation 5710 // through the select. 5711 if (LHS.getOpcode() == RHS.getOpcode() && LHS.hasOneUse() && RHS.hasOneUse()){ 5712 // If this is a load and the token chain is identical, replace the select 5713 // of two loads with a load through a select of the address to load from. 5714 // This triggers in things like "select bool X, 10.0, 123.0" after the FP 5715 // constants have been dropped into the constant pool. 5716 if (LHS.getOpcode() == ISD::LOAD && 5717 // Do not let this transformation reduce the number of volatile loads. 5718 !cast<LoadSDNode>(LHS)->isVolatile() && 5719 !cast<LoadSDNode>(RHS)->isVolatile() && 5720 // Token chains must be identical. 5721 LHS.getOperand(0) == RHS.getOperand(0)) { 5722 LoadSDNode *LLD = cast<LoadSDNode>(LHS); 5723 LoadSDNode *RLD = cast<LoadSDNode>(RHS); 5724 5725 // If this is an EXTLOAD, the VT's must match. 5726 if (LLD->getMemoryVT() == RLD->getMemoryVT()) { 5727 // FIXME: this discards src value information. This is 5728 // over-conservative. It would be beneficial to be able to remember 5729 // both potential memory locations. 5730 SDValue Addr; 5731 if (TheSelect->getOpcode() == ISD::SELECT) { 5732 // Check that the condition doesn't reach either load. If so, folding 5733 // this will induce a cycle into the DAG. 5734 if ((!LLD->hasAnyUseOfValue(1) || 5735 !LLD->isPredecessorOf(TheSelect->getOperand(0).getNode())) && 5736 (!RLD->hasAnyUseOfValue(1) || 5737 !RLD->isPredecessorOf(TheSelect->getOperand(0).getNode()))) { 5738 Addr = DAG.getNode(ISD::SELECT, TheSelect->getDebugLoc(), 5739 LLD->getBasePtr().getValueType(), 5740 TheSelect->getOperand(0), LLD->getBasePtr(), 5741 RLD->getBasePtr()); 5742 } 5743 } else { 5744 // Check that the condition doesn't reach either load. If so, folding 5745 // this will induce a cycle into the DAG. 5746 if ((!LLD->hasAnyUseOfValue(1) || 5747 (!LLD->isPredecessorOf(TheSelect->getOperand(0).getNode()) && 5748 !LLD->isPredecessorOf(TheSelect->getOperand(1).getNode()))) && 5749 (!RLD->hasAnyUseOfValue(1) || 5750 (!RLD->isPredecessorOf(TheSelect->getOperand(0).getNode()) && 5751 !RLD->isPredecessorOf(TheSelect->getOperand(1).getNode())))) { 5752 Addr = DAG.getNode(ISD::SELECT_CC, TheSelect->getDebugLoc(), 5753 LLD->getBasePtr().getValueType(), 5754 TheSelect->getOperand(0), 5755 TheSelect->getOperand(1), 5756 LLD->getBasePtr(), RLD->getBasePtr(), 5757 TheSelect->getOperand(4)); 5758 } 5759 } 5760 5761 if (Addr.getNode()) { 5762 SDValue Load; 5763 if (LLD->getExtensionType() == ISD::NON_EXTLOAD) { 5764 Load = DAG.getLoad(TheSelect->getValueType(0), 5765 TheSelect->getDebugLoc(), 5766 LLD->getChain(), 5767 Addr, 0, 0, 5768 LLD->isVolatile(), 5769 LLD->getAlignment()); 5770 } else { 5771 Load = DAG.getExtLoad(LLD->getExtensionType(), 5772 TheSelect->getDebugLoc(), 5773 TheSelect->getValueType(0), 5774 LLD->getChain(), Addr, 0, 0, 5775 LLD->getMemoryVT(), 5776 LLD->isVolatile(), 5777 LLD->getAlignment()); 5778 } 5779 5780 // Users of the select now use the result of the load. 5781 CombineTo(TheSelect, Load); 5782 5783 // Users of the old loads now use the new load's chain. We know the 5784 // old-load value is dead now. 5785 CombineTo(LHS.getNode(), Load.getValue(0), Load.getValue(1)); 5786 CombineTo(RHS.getNode(), Load.getValue(0), Load.getValue(1)); 5787 return true; 5788 } 5789 } 5790 } 5791 } 5792 5793 return false; 5794} 5795 5796/// SimplifySelectCC - Simplify an expression of the form (N0 cond N1) ? N2 : N3 5797/// where 'cond' is the comparison specified by CC. 5798SDValue DAGCombiner::SimplifySelectCC(DebugLoc DL, SDValue N0, SDValue N1, 5799 SDValue N2, SDValue N3, 5800 ISD::CondCode CC, bool NotExtCompare) { 5801 // (x ? y : y) -> y. 5802 if (N2 == N3) return N2; 5803 5804 EVT VT = N2.getValueType(); 5805 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.getNode()); 5806 ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(N2.getNode()); 5807 ConstantSDNode *N3C = dyn_cast<ConstantSDNode>(N3.getNode()); 5808 5809 // Determine if the condition we're dealing with is constant 5810 SDValue SCC = SimplifySetCC(TLI.getSetCCResultType(N0.getValueType()), 5811 N0, N1, CC, DL, false); 5812 if (SCC.getNode()) AddToWorkList(SCC.getNode()); 5813 ConstantSDNode *SCCC = dyn_cast_or_null<ConstantSDNode>(SCC.getNode()); 5814 5815 // fold select_cc true, x, y -> x 5816 if (SCCC && !SCCC->isNullValue()) 5817 return N2; 5818 // fold select_cc false, x, y -> y 5819 if (SCCC && SCCC->isNullValue()) 5820 return N3; 5821 5822 // Check to see if we can simplify the select into an fabs node 5823 if (ConstantFPSDNode *CFP = dyn_cast<ConstantFPSDNode>(N1)) { 5824 // Allow either -0.0 or 0.0 5825 if (CFP->getValueAPF().isZero()) { 5826 // select (setg[te] X, +/-0.0), X, fneg(X) -> fabs 5827 if ((CC == ISD::SETGE || CC == ISD::SETGT) && 5828 N0 == N2 && N3.getOpcode() == ISD::FNEG && 5829 N2 == N3.getOperand(0)) 5830 return DAG.getNode(ISD::FABS, DL, VT, N0); 5831 5832 // select (setl[te] X, +/-0.0), fneg(X), X -> fabs 5833 if ((CC == ISD::SETLT || CC == ISD::SETLE) && 5834 N0 == N3 && N2.getOpcode() == ISD::FNEG && 5835 N2.getOperand(0) == N3) 5836 return DAG.getNode(ISD::FABS, DL, VT, N3); 5837 } 5838 } 5839 5840 // Turn "(a cond b) ? 1.0f : 2.0f" into "load (tmp + ((a cond b) ? 0 : 4)" 5841 // where "tmp" is a constant pool entry containing an array with 1.0 and 2.0 5842 // in it. This is a win when the constant is not otherwise available because 5843 // it replaces two constant pool loads with one. We only do this if the FP 5844 // type is known to be legal, because if it isn't, then we are before legalize 5845 // types an we want the other legalization to happen first (e.g. to avoid 5846 // messing with soft float) and if the ConstantFP is not legal, because if 5847 // it is legal, we may not need to store the FP constant in a constant pool. 5848 if (ConstantFPSDNode *TV = dyn_cast<ConstantFPSDNode>(N2)) 5849 if (ConstantFPSDNode *FV = dyn_cast<ConstantFPSDNode>(N3)) { 5850 if (TLI.isTypeLegal(N2.getValueType()) && 5851 (TLI.getOperationAction(ISD::ConstantFP, N2.getValueType()) != 5852 TargetLowering::Legal) && 5853 // If both constants have multiple uses, then we won't need to do an 5854 // extra load, they are likely around in registers for other users. 5855 (TV->hasOneUse() || FV->hasOneUse())) { 5856 Constant *Elts[] = { 5857 const_cast<ConstantFP*>(FV->getConstantFPValue()), 5858 const_cast<ConstantFP*>(TV->getConstantFPValue()) 5859 }; 5860 const Type *FPTy = Elts[0]->getType(); 5861 const TargetData &TD = *TLI.getTargetData(); 5862 5863 // Create a ConstantArray of the two constants. 5864 Constant *CA = ConstantArray::get(ArrayType::get(FPTy, 2), Elts, 2); 5865 SDValue CPIdx = DAG.getConstantPool(CA, TLI.getPointerTy(), 5866 TD.getPrefTypeAlignment(FPTy)); 5867 unsigned Alignment = cast<ConstantPoolSDNode>(CPIdx)->getAlignment(); 5868 5869 // Get the offsets to the 0 and 1 element of the array so that we can 5870 // select between them. 5871 SDValue Zero = DAG.getIntPtrConstant(0); 5872 unsigned EltSize = (unsigned)TD.getTypeAllocSize(Elts[0]->getType()); 5873 SDValue One = DAG.getIntPtrConstant(EltSize); 5874 5875 SDValue Cond = DAG.getSetCC(DL, 5876 TLI.getSetCCResultType(N0.getValueType()), 5877 N0, N1, CC); 5878 SDValue CstOffset = DAG.getNode(ISD::SELECT, DL, Zero.getValueType(), 5879 Cond, One, Zero); 5880 CPIdx = DAG.getNode(ISD::ADD, DL, TLI.getPointerTy(), CPIdx, 5881 CstOffset); 5882 return DAG.getLoad(TV->getValueType(0), DL, DAG.getEntryNode(), CPIdx, 5883 PseudoSourceValue::getConstantPool(), 0, false, 5884 Alignment); 5885 5886 } 5887 } 5888 5889 // Check to see if we can perform the "gzip trick", transforming 5890 // (select_cc setlt X, 0, A, 0) -> (and (sra X, (sub size(X), 1), A) 5891 if (N1C && N3C && N3C->isNullValue() && CC == ISD::SETLT && 5892 N0.getValueType().isInteger() && 5893 N2.getValueType().isInteger() && 5894 (N1C->isNullValue() || // (a < 0) ? b : 0 5895 (N1C->getAPIntValue() == 1 && N0 == N2))) { // (a < 1) ? a : 0 5896 EVT XType = N0.getValueType(); 5897 EVT AType = N2.getValueType(); 5898 if (XType.bitsGE(AType)) { 5899 // and (sra X, size(X)-1, A) -> "and (srl X, C2), A" iff A is a 5900 // single-bit constant. 5901 if (N2C && ((N2C->getAPIntValue() & (N2C->getAPIntValue()-1)) == 0)) { 5902 unsigned ShCtV = N2C->getAPIntValue().logBase2(); 5903 ShCtV = XType.getSizeInBits()-ShCtV-1; 5904 SDValue ShCt = DAG.getConstant(ShCtV, getShiftAmountTy()); 5905 SDValue Shift = DAG.getNode(ISD::SRL, N0.getDebugLoc(), 5906 XType, N0, ShCt); 5907 AddToWorkList(Shift.getNode()); 5908 5909 if (XType.bitsGT(AType)) { 5910 Shift = DAG.getNode(ISD::TRUNCATE, DL, AType, Shift); 5911 AddToWorkList(Shift.getNode()); 5912 } 5913 5914 return DAG.getNode(ISD::AND, DL, AType, Shift, N2); 5915 } 5916 5917 SDValue Shift = DAG.getNode(ISD::SRA, N0.getDebugLoc(), 5918 XType, N0, 5919 DAG.getConstant(XType.getSizeInBits()-1, 5920 getShiftAmountTy())); 5921 AddToWorkList(Shift.getNode()); 5922 5923 if (XType.bitsGT(AType)) { 5924 Shift = DAG.getNode(ISD::TRUNCATE, DL, AType, Shift); 5925 AddToWorkList(Shift.getNode()); 5926 } 5927 5928 return DAG.getNode(ISD::AND, DL, AType, Shift, N2); 5929 } 5930 } 5931 5932 // fold select C, 16, 0 -> shl C, 4 5933 if (N2C && N3C && N3C->isNullValue() && N2C->getAPIntValue().isPowerOf2() && 5934 TLI.getBooleanContents() == TargetLowering::ZeroOrOneBooleanContent) { 5935 5936 // If the caller doesn't want us to simplify this into a zext of a compare, 5937 // don't do it. 5938 if (NotExtCompare && N2C->getAPIntValue() == 1) 5939 return SDValue(); 5940 5941 // Get a SetCC of the condition 5942 // FIXME: Should probably make sure that setcc is legal if we ever have a 5943 // target where it isn't. 5944 SDValue Temp, SCC; 5945 // cast from setcc result type to select result type 5946 if (LegalTypes) { 5947 SCC = DAG.getSetCC(DL, TLI.getSetCCResultType(N0.getValueType()), 5948 N0, N1, CC); 5949 if (N2.getValueType().bitsLT(SCC.getValueType())) 5950 Temp = DAG.getZeroExtendInReg(SCC, N2.getDebugLoc(), N2.getValueType()); 5951 else 5952 Temp = DAG.getNode(ISD::ZERO_EXTEND, N2.getDebugLoc(), 5953 N2.getValueType(), SCC); 5954 } else { 5955 SCC = DAG.getSetCC(N0.getDebugLoc(), MVT::i1, N0, N1, CC); 5956 Temp = DAG.getNode(ISD::ZERO_EXTEND, N2.getDebugLoc(), 5957 N2.getValueType(), SCC); 5958 } 5959 5960 AddToWorkList(SCC.getNode()); 5961 AddToWorkList(Temp.getNode()); 5962 5963 if (N2C->getAPIntValue() == 1) 5964 return Temp; 5965 5966 // shl setcc result by log2 n2c 5967 return DAG.getNode(ISD::SHL, DL, N2.getValueType(), Temp, 5968 DAG.getConstant(N2C->getAPIntValue().logBase2(), 5969 getShiftAmountTy())); 5970 } 5971 5972 // Check to see if this is the equivalent of setcc 5973 // FIXME: Turn all of these into setcc if setcc if setcc is legal 5974 // otherwise, go ahead with the folds. 5975 if (0 && N3C && N3C->isNullValue() && N2C && (N2C->getAPIntValue() == 1ULL)) { 5976 EVT XType = N0.getValueType(); 5977 if (!LegalOperations || 5978 TLI.isOperationLegal(ISD::SETCC, TLI.getSetCCResultType(XType))) { 5979 SDValue Res = DAG.getSetCC(DL, TLI.getSetCCResultType(XType), N0, N1, CC); 5980 if (Res.getValueType() != VT) 5981 Res = DAG.getNode(ISD::ZERO_EXTEND, DL, VT, Res); 5982 return Res; 5983 } 5984 5985 // fold (seteq X, 0) -> (srl (ctlz X, log2(size(X)))) 5986 if (N1C && N1C->isNullValue() && CC == ISD::SETEQ && 5987 (!LegalOperations || 5988 TLI.isOperationLegal(ISD::CTLZ, XType))) { 5989 SDValue Ctlz = DAG.getNode(ISD::CTLZ, N0.getDebugLoc(), XType, N0); 5990 return DAG.getNode(ISD::SRL, DL, XType, Ctlz, 5991 DAG.getConstant(Log2_32(XType.getSizeInBits()), 5992 getShiftAmountTy())); 5993 } 5994 // fold (setgt X, 0) -> (srl (and (-X, ~X), size(X)-1)) 5995 if (N1C && N1C->isNullValue() && CC == ISD::SETGT) { 5996 SDValue NegN0 = DAG.getNode(ISD::SUB, N0.getDebugLoc(), 5997 XType, DAG.getConstant(0, XType), N0); 5998 SDValue NotN0 = DAG.getNOT(N0.getDebugLoc(), N0, XType); 5999 return DAG.getNode(ISD::SRL, DL, XType, 6000 DAG.getNode(ISD::AND, DL, XType, NegN0, NotN0), 6001 DAG.getConstant(XType.getSizeInBits()-1, 6002 getShiftAmountTy())); 6003 } 6004 // fold (setgt X, -1) -> (xor (srl (X, size(X)-1), 1)) 6005 if (N1C && N1C->isAllOnesValue() && CC == ISD::SETGT) { 6006 SDValue Sign = DAG.getNode(ISD::SRL, N0.getDebugLoc(), XType, N0, 6007 DAG.getConstant(XType.getSizeInBits()-1, 6008 getShiftAmountTy())); 6009 return DAG.getNode(ISD::XOR, DL, XType, Sign, DAG.getConstant(1, XType)); 6010 } 6011 } 6012 6013 // Check to see if this is an integer abs. select_cc setl[te] X, 0, -X, X -> 6014 // Y = sra (X, size(X)-1); xor (add (X, Y), Y) 6015 if (N1C && N1C->isNullValue() && (CC == ISD::SETLT || CC == ISD::SETLE) && 6016 N0 == N3 && N2.getOpcode() == ISD::SUB && N0 == N2.getOperand(1) && 6017 N2.getOperand(0) == N1 && N0.getValueType().isInteger()) { 6018 EVT XType = N0.getValueType(); 6019 SDValue Shift = DAG.getNode(ISD::SRA, N0.getDebugLoc(), XType, N0, 6020 DAG.getConstant(XType.getSizeInBits()-1, 6021 getShiftAmountTy())); 6022 SDValue Add = DAG.getNode(ISD::ADD, N0.getDebugLoc(), XType, 6023 N0, Shift); 6024 AddToWorkList(Shift.getNode()); 6025 AddToWorkList(Add.getNode()); 6026 return DAG.getNode(ISD::XOR, DL, XType, Add, Shift); 6027 } 6028 // Check to see if this is an integer abs. select_cc setgt X, -1, X, -X -> 6029 // Y = sra (X, size(X)-1); xor (add (X, Y), Y) 6030 if (N1C && N1C->isAllOnesValue() && CC == ISD::SETGT && 6031 N0 == N2 && N3.getOpcode() == ISD::SUB && N0 == N3.getOperand(1)) { 6032 if (ConstantSDNode *SubC = dyn_cast<ConstantSDNode>(N3.getOperand(0))) { 6033 EVT XType = N0.getValueType(); 6034 if (SubC->isNullValue() && XType.isInteger()) { 6035 SDValue Shift = DAG.getNode(ISD::SRA, N0.getDebugLoc(), XType, 6036 N0, 6037 DAG.getConstant(XType.getSizeInBits()-1, 6038 getShiftAmountTy())); 6039 SDValue Add = DAG.getNode(ISD::ADD, N0.getDebugLoc(), 6040 XType, N0, Shift); 6041 AddToWorkList(Shift.getNode()); 6042 AddToWorkList(Add.getNode()); 6043 return DAG.getNode(ISD::XOR, DL, XType, Add, Shift); 6044 } 6045 } 6046 } 6047 6048 return SDValue(); 6049} 6050 6051/// SimplifySetCC - This is a stub for TargetLowering::SimplifySetCC. 6052SDValue DAGCombiner::SimplifySetCC(EVT VT, SDValue N0, 6053 SDValue N1, ISD::CondCode Cond, 6054 DebugLoc DL, bool foldBooleans) { 6055 TargetLowering::DAGCombinerInfo 6056 DagCombineInfo(DAG, !LegalTypes, !LegalOperations, false, this); 6057 return TLI.SimplifySetCC(VT, N0, N1, Cond, foldBooleans, DagCombineInfo, DL); 6058} 6059 6060/// BuildSDIVSequence - Given an ISD::SDIV node expressing a divide by constant, 6061/// return a DAG expression to select that will generate the same value by 6062/// multiplying by a magic number. See: 6063/// <http://the.wall.riscom.net/books/proc/ppc/cwg/code2.html> 6064SDValue DAGCombiner::BuildSDIV(SDNode *N) { 6065 std::vector<SDNode*> Built; 6066 SDValue S = TLI.BuildSDIV(N, DAG, &Built); 6067 6068 for (std::vector<SDNode*>::iterator ii = Built.begin(), ee = Built.end(); 6069 ii != ee; ++ii) 6070 AddToWorkList(*ii); 6071 return S; 6072} 6073 6074/// BuildUDIVSequence - Given an ISD::UDIV node expressing a divide by constant, 6075/// return a DAG expression to select that will generate the same value by 6076/// multiplying by a magic number. See: 6077/// <http://the.wall.riscom.net/books/proc/ppc/cwg/code2.html> 6078SDValue DAGCombiner::BuildUDIV(SDNode *N) { 6079 std::vector<SDNode*> Built; 6080 SDValue S = TLI.BuildUDIV(N, DAG, &Built); 6081 6082 for (std::vector<SDNode*>::iterator ii = Built.begin(), ee = Built.end(); 6083 ii != ee; ++ii) 6084 AddToWorkList(*ii); 6085 return S; 6086} 6087 6088/// FindBaseOffset - Return true if base is a frame index, which is known not 6089// to alias with anything but itself. Provides base object and offset as results. 6090static bool FindBaseOffset(SDValue Ptr, SDValue &Base, int64_t &Offset, 6091 GlobalValue *&GV, void *&CV) { 6092 // Assume it is a primitive operation. 6093 Base = Ptr; Offset = 0; GV = 0; CV = 0; 6094 6095 // If it's an adding a simple constant then integrate the offset. 6096 if (Base.getOpcode() == ISD::ADD) { 6097 if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Base.getOperand(1))) { 6098 Base = Base.getOperand(0); 6099 Offset += C->getZExtValue(); 6100 } 6101 } 6102 6103 // Return the underlying GlobalValue, and update the Offset. Return false 6104 // for GlobalAddressSDNode since the same GlobalAddress may be represented 6105 // by multiple nodes with different offsets. 6106 if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Base)) { 6107 GV = G->getGlobal(); 6108 Offset += G->getOffset(); 6109 return false; 6110 } 6111 6112 // Return the underlying Constant value, and update the Offset. Return false 6113 // for ConstantSDNodes since the same constant pool entry may be represented 6114 // by multiple nodes with different offsets. 6115 if (ConstantPoolSDNode *C = dyn_cast<ConstantPoolSDNode>(Base)) { 6116 CV = C->isMachineConstantPoolEntry() ? (void *)C->getMachineCPVal() 6117 : (void *)C->getConstVal(); 6118 Offset += C->getOffset(); 6119 return false; 6120 } 6121 // If it's any of the following then it can't alias with anything but itself. 6122 return isa<FrameIndexSDNode>(Base); 6123} 6124 6125/// isAlias - Return true if there is any possibility that the two addresses 6126/// overlap. 6127bool DAGCombiner::isAlias(SDValue Ptr1, int64_t Size1, 6128 const Value *SrcValue1, int SrcValueOffset1, 6129 unsigned SrcValueAlign1, 6130 SDValue Ptr2, int64_t Size2, 6131 const Value *SrcValue2, int SrcValueOffset2, 6132 unsigned SrcValueAlign2) const { 6133 // If they are the same then they must be aliases. 6134 if (Ptr1 == Ptr2) return true; 6135 6136 // Gather base node and offset information. 6137 SDValue Base1, Base2; 6138 int64_t Offset1, Offset2; 6139 GlobalValue *GV1, *GV2; 6140 void *CV1, *CV2; 6141 bool isFrameIndex1 = FindBaseOffset(Ptr1, Base1, Offset1, GV1, CV1); 6142 bool isFrameIndex2 = FindBaseOffset(Ptr2, Base2, Offset2, GV2, CV2); 6143 6144 // If they have a same base address then check to see if they overlap. 6145 if (Base1 == Base2 || (GV1 && (GV1 == GV2)) || (CV1 && (CV1 == CV2))) 6146 return !((Offset1 + Size1) <= Offset2 || (Offset2 + Size2) <= Offset1); 6147 6148 // If we know what the bases are, and they aren't identical, then we know they 6149 // cannot alias. 6150 if ((isFrameIndex1 || CV1 || GV1) && (isFrameIndex2 || CV2 || GV2)) 6151 return false; 6152 6153 // If we know required SrcValue1 and SrcValue2 have relatively large alignment 6154 // compared to the size and offset of the access, we may be able to prove they 6155 // do not alias. This check is conservative for now to catch cases created by 6156 // splitting vector types. 6157 if ((SrcValueAlign1 == SrcValueAlign2) && 6158 (SrcValueOffset1 != SrcValueOffset2) && 6159 (Size1 == Size2) && (SrcValueAlign1 > Size1)) { 6160 int64_t OffAlign1 = SrcValueOffset1 % SrcValueAlign1; 6161 int64_t OffAlign2 = SrcValueOffset2 % SrcValueAlign1; 6162 6163 // There is no overlap between these relatively aligned accesses of similar 6164 // size, return no alias. 6165 if ((OffAlign1 + Size1) <= OffAlign2 || (OffAlign2 + Size2) <= OffAlign1) 6166 return false; 6167 } 6168 6169 if (CombinerGlobalAA) { 6170 // Use alias analysis information. 6171 int64_t MinOffset = std::min(SrcValueOffset1, SrcValueOffset2); 6172 int64_t Overlap1 = Size1 + SrcValueOffset1 - MinOffset; 6173 int64_t Overlap2 = Size2 + SrcValueOffset2 - MinOffset; 6174 AliasAnalysis::AliasResult AAResult = 6175 AA.alias(SrcValue1, Overlap1, SrcValue2, Overlap2); 6176 if (AAResult == AliasAnalysis::NoAlias) 6177 return false; 6178 } 6179 6180 // Otherwise we have to assume they alias. 6181 return true; 6182} 6183 6184/// FindAliasInfo - Extracts the relevant alias information from the memory 6185/// node. Returns true if the operand was a load. 6186bool DAGCombiner::FindAliasInfo(SDNode *N, 6187 SDValue &Ptr, int64_t &Size, 6188 const Value *&SrcValue, 6189 int &SrcValueOffset, 6190 unsigned &SrcValueAlign) const { 6191 if (LoadSDNode *LD = dyn_cast<LoadSDNode>(N)) { 6192 Ptr = LD->getBasePtr(); 6193 Size = LD->getMemoryVT().getSizeInBits() >> 3; 6194 SrcValue = LD->getSrcValue(); 6195 SrcValueOffset = LD->getSrcValueOffset(); 6196 SrcValueAlign = LD->getOriginalAlignment(); 6197 return true; 6198 } else if (StoreSDNode *ST = dyn_cast<StoreSDNode>(N)) { 6199 Ptr = ST->getBasePtr(); 6200 Size = ST->getMemoryVT().getSizeInBits() >> 3; 6201 SrcValue = ST->getSrcValue(); 6202 SrcValueOffset = ST->getSrcValueOffset(); 6203 SrcValueAlign = ST->getOriginalAlignment(); 6204 } else { 6205 llvm_unreachable("FindAliasInfo expected a memory operand"); 6206 } 6207 6208 return false; 6209} 6210 6211/// GatherAllAliases - Walk up chain skipping non-aliasing memory nodes, 6212/// looking for aliasing nodes and adding them to the Aliases vector. 6213void DAGCombiner::GatherAllAliases(SDNode *N, SDValue OriginalChain, 6214 SmallVector<SDValue, 8> &Aliases) { 6215 SmallVector<SDValue, 8> Chains; // List of chains to visit. 6216 SmallPtrSet<SDNode *, 16> Visited; // Visited node set. 6217 6218 // Get alias information for node. 6219 SDValue Ptr; 6220 int64_t Size; 6221 const Value *SrcValue; 6222 int SrcValueOffset; 6223 unsigned SrcValueAlign; 6224 bool IsLoad = FindAliasInfo(N, Ptr, Size, SrcValue, SrcValueOffset, 6225 SrcValueAlign); 6226 6227 // Starting off. 6228 Chains.push_back(OriginalChain); 6229 unsigned Depth = 0; 6230 6231 // Look at each chain and determine if it is an alias. If so, add it to the 6232 // aliases list. If not, then continue up the chain looking for the next 6233 // candidate. 6234 while (!Chains.empty()) { 6235 SDValue Chain = Chains.back(); 6236 Chains.pop_back(); 6237 6238 // For TokenFactor nodes, look at each operand and only continue up the 6239 // chain until we find two aliases. If we've seen two aliases, assume we'll 6240 // find more and revert to original chain since the xform is unlikely to be 6241 // profitable. 6242 // 6243 // FIXME: The depth check could be made to return the last non-aliasing 6244 // chain we found before we hit a tokenfactor rather than the original 6245 // chain. 6246 if (Depth > 6 || Aliases.size() == 2) { 6247 Aliases.clear(); 6248 Aliases.push_back(OriginalChain); 6249 break; 6250 } 6251 6252 // Don't bother if we've been before. 6253 if (!Visited.insert(Chain.getNode())) 6254 continue; 6255 6256 switch (Chain.getOpcode()) { 6257 case ISD::EntryToken: 6258 // Entry token is ideal chain operand, but handled in FindBetterChain. 6259 break; 6260 6261 case ISD::LOAD: 6262 case ISD::STORE: { 6263 // Get alias information for Chain. 6264 SDValue OpPtr; 6265 int64_t OpSize; 6266 const Value *OpSrcValue; 6267 int OpSrcValueOffset; 6268 unsigned OpSrcValueAlign; 6269 bool IsOpLoad = FindAliasInfo(Chain.getNode(), OpPtr, OpSize, 6270 OpSrcValue, OpSrcValueOffset, 6271 OpSrcValueAlign); 6272 6273 // If chain is alias then stop here. 6274 if (!(IsLoad && IsOpLoad) && 6275 isAlias(Ptr, Size, SrcValue, SrcValueOffset, SrcValueAlign, 6276 OpPtr, OpSize, OpSrcValue, OpSrcValueOffset, 6277 OpSrcValueAlign)) { 6278 Aliases.push_back(Chain); 6279 } else { 6280 // Look further up the chain. 6281 Chains.push_back(Chain.getOperand(0)); 6282 ++Depth; 6283 } 6284 break; 6285 } 6286 6287 case ISD::TokenFactor: 6288 // We have to check each of the operands of the token factor for "small" 6289 // token factors, so we queue them up. Adding the operands to the queue 6290 // (stack) in reverse order maintains the original order and increases the 6291 // likelihood that getNode will find a matching token factor (CSE.) 6292 if (Chain.getNumOperands() > 16) { 6293 Aliases.push_back(Chain); 6294 break; 6295 } 6296 for (unsigned n = Chain.getNumOperands(); n;) 6297 Chains.push_back(Chain.getOperand(--n)); 6298 ++Depth; 6299 break; 6300 6301 default: 6302 // For all other instructions we will just have to take what we can get. 6303 Aliases.push_back(Chain); 6304 break; 6305 } 6306 } 6307} 6308 6309/// FindBetterChain - Walk up chain skipping non-aliasing memory nodes, looking 6310/// for a better chain (aliasing node.) 6311SDValue DAGCombiner::FindBetterChain(SDNode *N, SDValue OldChain) { 6312 SmallVector<SDValue, 8> Aliases; // Ops for replacing token factor. 6313 6314 // Accumulate all the aliases to this node. 6315 GatherAllAliases(N, OldChain, Aliases); 6316 6317 if (Aliases.size() == 0) { 6318 // If no operands then chain to entry token. 6319 return DAG.getEntryNode(); 6320 } else if (Aliases.size() == 1) { 6321 // If a single operand then chain to it. We don't need to revisit it. 6322 return Aliases[0]; 6323 } 6324 6325 // Construct a custom tailored token factor. 6326 return DAG.getNode(ISD::TokenFactor, N->getDebugLoc(), MVT::Other, 6327 &Aliases[0], Aliases.size()); 6328} 6329 6330// SelectionDAG::Combine - This is the entry point for the file. 6331// 6332void SelectionDAG::Combine(CombineLevel Level, AliasAnalysis &AA, 6333 CodeGenOpt::Level OptLevel) { 6334 /// run - This is the main entry point to this class. 6335 /// 6336 DAGCombiner(*this, AA, OptLevel).Run(Level); 6337} 6338