DAGCombiner.cpp revision 81a42cf05bf437d155f5491b490b1204c0acccfb
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//===----------------------------------------------------------------------===// 14 15#define DEBUG_TYPE "dagcombine" 16#include "llvm/CodeGen/SelectionDAG.h" 17#include "llvm/CodeGen/MachineFunction.h" 18#include "llvm/CodeGen/MachineFrameInfo.h" 19#include "llvm/Analysis/AliasAnalysis.h" 20#include "llvm/Target/TargetData.h" 21#include "llvm/Target/TargetFrameInfo.h" 22#include "llvm/Target/TargetLowering.h" 23#include "llvm/Target/TargetMachine.h" 24#include "llvm/Target/TargetOptions.h" 25#include "llvm/ADT/SmallPtrSet.h" 26#include "llvm/ADT/Statistic.h" 27#include "llvm/Support/Compiler.h" 28#include "llvm/Support/CommandLine.h" 29#include "llvm/Support/Debug.h" 30#include "llvm/Support/MathExtras.h" 31#include <algorithm> 32#include <set> 33using namespace llvm; 34 35STATISTIC(NodesCombined , "Number of dag nodes combined"); 36STATISTIC(PreIndexedNodes , "Number of pre-indexed nodes created"); 37STATISTIC(PostIndexedNodes, "Number of post-indexed nodes created"); 38 39namespace { 40 static cl::opt<bool> 41 CombinerAA("combiner-alias-analysis", cl::Hidden, 42 cl::desc("Turn on alias analysis during testing")); 43 44 static cl::opt<bool> 45 CombinerGlobalAA("combiner-global-alias-analysis", cl::Hidden, 46 cl::desc("Include global information in alias analysis")); 47 48//------------------------------ DAGCombiner ---------------------------------// 49 50 class VISIBILITY_HIDDEN DAGCombiner { 51 SelectionDAG &DAG; 52 const TargetLowering &TLI; 53 CombineLevel Level; 54 bool LegalOperations; 55 bool LegalTypes; 56 bool Fast; 57 58 // Worklist of all of the nodes that need to be simplified. 59 std::vector<SDNode*> WorkList; 60 61 // AA - Used for DAG load/store alias analysis. 62 AliasAnalysis &AA; 63 64 /// AddUsersToWorkList - When an instruction is simplified, add all users of 65 /// the instruction to the work lists because they might get more simplified 66 /// now. 67 /// 68 void AddUsersToWorkList(SDNode *N) { 69 for (SDNode::use_iterator UI = N->use_begin(), UE = N->use_end(); 70 UI != UE; ++UI) 71 AddToWorkList(*UI); 72 } 73 74 /// visit - call the node-specific routine that knows how to fold each 75 /// particular type of node. 76 SDValue visit(SDNode *N); 77 78 public: 79 /// AddToWorkList - Add to the work list making sure it's instance is at the 80 /// the back (next to be processed.) 81 void AddToWorkList(SDNode *N) { 82 removeFromWorkList(N); 83 WorkList.push_back(N); 84 } 85 86 /// removeFromWorkList - remove all instances of N from the worklist. 87 /// 88 void removeFromWorkList(SDNode *N) { 89 WorkList.erase(std::remove(WorkList.begin(), WorkList.end(), N), 90 WorkList.end()); 91 } 92 93 SDValue CombineTo(SDNode *N, const SDValue *To, unsigned NumTo, 94 bool AddTo = true); 95 96 SDValue CombineTo(SDNode *N, SDValue Res, bool AddTo = true) { 97 return CombineTo(N, &Res, 1, AddTo); 98 } 99 100 SDValue CombineTo(SDNode *N, SDValue Res0, SDValue Res1, 101 bool AddTo = true) { 102 SDValue To[] = { Res0, Res1 }; 103 return CombineTo(N, To, 2, AddTo); 104 } 105 106 private: 107 108 /// SimplifyDemandedBits - Check the specified integer node value to see if 109 /// it can be simplified or if things it uses can be simplified by bit 110 /// propagation. If so, return true. 111 bool SimplifyDemandedBits(SDValue Op) { 112 APInt Demanded = APInt::getAllOnesValue(Op.getValueSizeInBits()); 113 return SimplifyDemandedBits(Op, Demanded); 114 } 115 116 bool SimplifyDemandedBits(SDValue Op, const APInt &Demanded); 117 118 bool CombineToPreIndexedLoadStore(SDNode *N); 119 bool CombineToPostIndexedLoadStore(SDNode *N); 120 121 122 /// combine - call the node-specific routine that knows how to fold each 123 /// particular type of node. If that doesn't do anything, try the 124 /// target-specific DAG combines. 125 SDValue combine(SDNode *N); 126 127 // Visitation implementation - Implement dag node combining for different 128 // node types. The semantics are as follows: 129 // Return Value: 130 // SDValue.getNode() == 0 - No change was made 131 // SDValue.getNode() == N - N was replaced, is dead and has been handled. 132 // otherwise - N should be replaced by the returned Operand. 133 // 134 SDValue visitTokenFactor(SDNode *N); 135 SDValue visitMERGE_VALUES(SDNode *N); 136 SDValue visitADD(SDNode *N); 137 SDValue visitSUB(SDNode *N); 138 SDValue visitADDC(SDNode *N); 139 SDValue visitADDE(SDNode *N); 140 SDValue visitMUL(SDNode *N); 141 SDValue visitSDIV(SDNode *N); 142 SDValue visitUDIV(SDNode *N); 143 SDValue visitSREM(SDNode *N); 144 SDValue visitUREM(SDNode *N); 145 SDValue visitMULHU(SDNode *N); 146 SDValue visitMULHS(SDNode *N); 147 SDValue visitSMUL_LOHI(SDNode *N); 148 SDValue visitUMUL_LOHI(SDNode *N); 149 SDValue visitSDIVREM(SDNode *N); 150 SDValue visitUDIVREM(SDNode *N); 151 SDValue visitAND(SDNode *N); 152 SDValue visitOR(SDNode *N); 153 SDValue visitXOR(SDNode *N); 154 SDValue SimplifyVBinOp(SDNode *N); 155 SDValue visitSHL(SDNode *N); 156 SDValue visitSRA(SDNode *N); 157 SDValue visitSRL(SDNode *N); 158 SDValue visitCTLZ(SDNode *N); 159 SDValue visitCTTZ(SDNode *N); 160 SDValue visitCTPOP(SDNode *N); 161 SDValue visitSELECT(SDNode *N); 162 SDValue visitSELECT_CC(SDNode *N); 163 SDValue visitSETCC(SDNode *N); 164 SDValue visitSIGN_EXTEND(SDNode *N); 165 SDValue visitZERO_EXTEND(SDNode *N); 166 SDValue visitANY_EXTEND(SDNode *N); 167 SDValue visitSIGN_EXTEND_INREG(SDNode *N); 168 SDValue visitTRUNCATE(SDNode *N); 169 SDValue visitBIT_CONVERT(SDNode *N); 170 SDValue visitBUILD_PAIR(SDNode *N); 171 SDValue visitFADD(SDNode *N); 172 SDValue visitFSUB(SDNode *N); 173 SDValue visitFMUL(SDNode *N); 174 SDValue visitFDIV(SDNode *N); 175 SDValue visitFREM(SDNode *N); 176 SDValue visitFCOPYSIGN(SDNode *N); 177 SDValue visitSINT_TO_FP(SDNode *N); 178 SDValue visitUINT_TO_FP(SDNode *N); 179 SDValue visitFP_TO_SINT(SDNode *N); 180 SDValue visitFP_TO_UINT(SDNode *N); 181 SDValue visitFP_ROUND(SDNode *N); 182 SDValue visitFP_ROUND_INREG(SDNode *N); 183 SDValue visitFP_EXTEND(SDNode *N); 184 SDValue visitFNEG(SDNode *N); 185 SDValue visitFABS(SDNode *N); 186 SDValue visitBRCOND(SDNode *N); 187 SDValue visitBR_CC(SDNode *N); 188 SDValue visitLOAD(SDNode *N); 189 SDValue visitSTORE(SDNode *N); 190 SDValue visitINSERT_VECTOR_ELT(SDNode *N); 191 SDValue visitEXTRACT_VECTOR_ELT(SDNode *N); 192 SDValue visitBUILD_VECTOR(SDNode *N); 193 SDValue visitCONCAT_VECTORS(SDNode *N); 194 SDValue visitVECTOR_SHUFFLE(SDNode *N); 195 196 SDValue XformToShuffleWithZero(SDNode *N); 197 SDValue ReassociateOps(unsigned Opc, SDValue LHS, SDValue RHS); 198 199 SDValue visitShiftByConstant(SDNode *N, unsigned Amt); 200 201 bool SimplifySelectOps(SDNode *SELECT, SDValue LHS, SDValue RHS); 202 SDValue SimplifyBinOpWithSameOpcodeHands(SDNode *N); 203 SDValue SimplifySelect(SDValue N0, SDValue N1, SDValue N2); 204 SDValue SimplifySelectCC(SDValue N0, SDValue N1, SDValue N2, 205 SDValue N3, ISD::CondCode CC, 206 bool NotExtCompare = false); 207 SDValue SimplifySetCC(MVT VT, SDValue N0, SDValue N1, ISD::CondCode Cond, 208 bool foldBooleans = true); 209 SDValue SimplifyNodeWithTwoResults(SDNode *N, unsigned LoOp, 210 unsigned HiOp); 211 SDValue CombineConsecutiveLoads(SDNode *N, MVT VT); 212 SDValue ConstantFoldBIT_CONVERTofBUILD_VECTOR(SDNode *, MVT); 213 SDValue BuildSDIV(SDNode *N); 214 SDValue BuildUDIV(SDNode *N); 215 SDNode *MatchRotate(SDValue LHS, SDValue RHS); 216 SDValue ReduceLoadWidth(SDNode *N); 217 218 SDValue GetDemandedBits(SDValue V, const APInt &Mask); 219 220 /// GatherAllAliases - Walk up chain skipping non-aliasing memory nodes, 221 /// looking for aliasing nodes and adding them to the Aliases vector. 222 void GatherAllAliases(SDNode *N, SDValue OriginalChain, 223 SmallVector<SDValue, 8> &Aliases); 224 225 /// isAlias - Return true if there is any possibility that the two addresses 226 /// overlap. 227 bool isAlias(SDValue Ptr1, int64_t Size1, 228 const Value *SrcValue1, int SrcValueOffset1, 229 SDValue Ptr2, int64_t Size2, 230 const Value *SrcValue2, int SrcValueOffset2); 231 232 /// FindAliasInfo - Extracts the relevant alias information from the memory 233 /// node. Returns true if the operand was a load. 234 bool FindAliasInfo(SDNode *N, 235 SDValue &Ptr, int64_t &Size, 236 const Value *&SrcValue, int &SrcValueOffset); 237 238 /// FindBetterChain - Walk up chain skipping non-aliasing memory nodes, 239 /// looking for a better chain (aliasing node.) 240 SDValue FindBetterChain(SDNode *N, SDValue Chain); 241 242public: 243 DAGCombiner(SelectionDAG &D, AliasAnalysis &A, bool fast) 244 : DAG(D), 245 TLI(D.getTargetLoweringInfo()), 246 Level(Unrestricted), 247 LegalOperations(false), 248 LegalTypes(false), 249 Fast(fast), 250 AA(A) {} 251 252 /// Run - runs the dag combiner on all nodes in the work list 253 void Run(CombineLevel AtLevel); 254 }; 255} 256 257 258namespace { 259/// WorkListRemover - This class is a DAGUpdateListener that removes any deleted 260/// nodes from the worklist. 261class VISIBILITY_HIDDEN WorkListRemover : 262 public SelectionDAG::DAGUpdateListener { 263 DAGCombiner &DC; 264public: 265 explicit WorkListRemover(DAGCombiner &dc) : DC(dc) {} 266 267 virtual void NodeDeleted(SDNode *N, SDNode *E) { 268 DC.removeFromWorkList(N); 269 } 270 271 virtual void NodeUpdated(SDNode *N) { 272 // Ignore updates. 273 } 274}; 275} 276 277//===----------------------------------------------------------------------===// 278// TargetLowering::DAGCombinerInfo implementation 279//===----------------------------------------------------------------------===// 280 281void TargetLowering::DAGCombinerInfo::AddToWorklist(SDNode *N) { 282 ((DAGCombiner*)DC)->AddToWorkList(N); 283} 284 285SDValue TargetLowering::DAGCombinerInfo:: 286CombineTo(SDNode *N, const std::vector<SDValue> &To) { 287 return ((DAGCombiner*)DC)->CombineTo(N, &To[0], To.size()); 288} 289 290SDValue TargetLowering::DAGCombinerInfo:: 291CombineTo(SDNode *N, SDValue Res) { 292 return ((DAGCombiner*)DC)->CombineTo(N, Res); 293} 294 295 296SDValue TargetLowering::DAGCombinerInfo:: 297CombineTo(SDNode *N, SDValue Res0, SDValue Res1) { 298 return ((DAGCombiner*)DC)->CombineTo(N, Res0, Res1); 299} 300 301 302//===----------------------------------------------------------------------===// 303// Helper Functions 304//===----------------------------------------------------------------------===// 305 306/// isNegatibleForFree - Return 1 if we can compute the negated form of the 307/// specified expression for the same cost as the expression itself, or 2 if we 308/// can compute the negated form more cheaply than the expression itself. 309static char isNegatibleForFree(SDValue Op, bool LegalOperations, 310 unsigned Depth = 0) { 311 // No compile time optimizations on this type. 312 if (Op.getValueType() == MVT::ppcf128) 313 return 0; 314 315 // fneg is removable even if it has multiple uses. 316 if (Op.getOpcode() == ISD::FNEG) return 2; 317 318 // Don't allow anything with multiple uses. 319 if (!Op.hasOneUse()) return 0; 320 321 // Don't recurse exponentially. 322 if (Depth > 6) return 0; 323 324 switch (Op.getOpcode()) { 325 default: return false; 326 case ISD::ConstantFP: 327 // Don't invert constant FP values after legalize. The negated constant 328 // isn't necessarily legal. 329 return LegalOperations ? 0 : 1; 330 case ISD::FADD: 331 // FIXME: determine better conditions for this xform. 332 if (!UnsafeFPMath) return 0; 333 334 // -(A+B) -> -A - B 335 if (char V = isNegatibleForFree(Op.getOperand(0), LegalOperations, Depth+1)) 336 return V; 337 // -(A+B) -> -B - A 338 return isNegatibleForFree(Op.getOperand(1), LegalOperations, Depth+1); 339 case ISD::FSUB: 340 // We can't turn -(A-B) into B-A when we honor signed zeros. 341 if (!UnsafeFPMath) return 0; 342 343 // -(A-B) -> B-A 344 return 1; 345 346 case ISD::FMUL: 347 case ISD::FDIV: 348 if (HonorSignDependentRoundingFPMath()) return 0; 349 350 // -(X*Y) -> (-X * Y) or (X*-Y) 351 if (char V = isNegatibleForFree(Op.getOperand(0), LegalOperations, Depth+1)) 352 return V; 353 354 return isNegatibleForFree(Op.getOperand(1), LegalOperations, Depth+1); 355 356 case ISD::FP_EXTEND: 357 case ISD::FP_ROUND: 358 case ISD::FSIN: 359 return isNegatibleForFree(Op.getOperand(0), LegalOperations, Depth+1); 360 } 361} 362 363/// GetNegatedExpression - If isNegatibleForFree returns true, this function 364/// returns the newly negated expression. 365static SDValue GetNegatedExpression(SDValue Op, SelectionDAG &DAG, 366 bool LegalOperations, unsigned Depth = 0) { 367 // fneg is removable even if it has multiple uses. 368 if (Op.getOpcode() == ISD::FNEG) return Op.getOperand(0); 369 370 // Don't allow anything with multiple uses. 371 assert(Op.hasOneUse() && "Unknown reuse!"); 372 373 assert(Depth <= 6 && "GetNegatedExpression doesn't match isNegatibleForFree"); 374 switch (Op.getOpcode()) { 375 default: assert(0 && "Unknown code"); 376 case ISD::ConstantFP: { 377 APFloat V = cast<ConstantFPSDNode>(Op)->getValueAPF(); 378 V.changeSign(); 379 return DAG.getConstantFP(V, Op.getValueType()); 380 } 381 case ISD::FADD: 382 // FIXME: determine better conditions for this xform. 383 assert(UnsafeFPMath); 384 385 // -(A+B) -> -A - B 386 if (isNegatibleForFree(Op.getOperand(0), LegalOperations, Depth+1)) 387 return DAG.getNode(ISD::FSUB, Op.getValueType(), 388 GetNegatedExpression(Op.getOperand(0), DAG, 389 LegalOperations, Depth+1), 390 Op.getOperand(1)); 391 // -(A+B) -> -B - A 392 return DAG.getNode(ISD::FSUB, Op.getValueType(), 393 GetNegatedExpression(Op.getOperand(1), DAG, 394 LegalOperations, Depth+1), 395 Op.getOperand(0)); 396 case ISD::FSUB: 397 // We can't turn -(A-B) into B-A when we honor signed zeros. 398 assert(UnsafeFPMath); 399 400 // -(0-B) -> B 401 if (ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(Op.getOperand(0))) 402 if (N0CFP->getValueAPF().isZero()) 403 return Op.getOperand(1); 404 405 // -(A-B) -> B-A 406 return DAG.getNode(ISD::FSUB, Op.getValueType(), Op.getOperand(1), 407 Op.getOperand(0)); 408 409 case ISD::FMUL: 410 case ISD::FDIV: 411 assert(!HonorSignDependentRoundingFPMath()); 412 413 // -(X*Y) -> -X * Y 414 if (isNegatibleForFree(Op.getOperand(0), LegalOperations, Depth+1)) 415 return DAG.getNode(Op.getOpcode(), Op.getValueType(), 416 GetNegatedExpression(Op.getOperand(0), DAG, 417 LegalOperations, Depth+1), 418 Op.getOperand(1)); 419 420 // -(X*Y) -> X * -Y 421 return DAG.getNode(Op.getOpcode(), Op.getValueType(), 422 Op.getOperand(0), 423 GetNegatedExpression(Op.getOperand(1), DAG, 424 LegalOperations, Depth+1)); 425 426 case ISD::FP_EXTEND: 427 case ISD::FSIN: 428 return DAG.getNode(Op.getOpcode(), Op.getValueType(), 429 GetNegatedExpression(Op.getOperand(0), DAG, 430 LegalOperations, Depth+1)); 431 case ISD::FP_ROUND: 432 return DAG.getNode(ISD::FP_ROUND, Op.getValueType(), 433 GetNegatedExpression(Op.getOperand(0), DAG, 434 LegalOperations, Depth+1), 435 Op.getOperand(1)); 436 } 437} 438 439 440// isSetCCEquivalent - Return true if this node is a setcc, or is a select_cc 441// that selects between the values 1 and 0, making it equivalent to a setcc. 442// Also, set the incoming LHS, RHS, and CC references to the appropriate 443// nodes based on the type of node we are checking. This simplifies life a 444// bit for the callers. 445static bool isSetCCEquivalent(SDValue N, SDValue &LHS, SDValue &RHS, 446 SDValue &CC) { 447 if (N.getOpcode() == ISD::SETCC) { 448 LHS = N.getOperand(0); 449 RHS = N.getOperand(1); 450 CC = N.getOperand(2); 451 return true; 452 } 453 if (N.getOpcode() == ISD::SELECT_CC && 454 N.getOperand(2).getOpcode() == ISD::Constant && 455 N.getOperand(3).getOpcode() == ISD::Constant && 456 cast<ConstantSDNode>(N.getOperand(2))->getAPIntValue() == 1 && 457 cast<ConstantSDNode>(N.getOperand(3))->isNullValue()) { 458 LHS = N.getOperand(0); 459 RHS = N.getOperand(1); 460 CC = N.getOperand(4); 461 return true; 462 } 463 return false; 464} 465 466// isOneUseSetCC - Return true if this is a SetCC-equivalent operation with only 467// one use. If this is true, it allows the users to invert the operation for 468// free when it is profitable to do so. 469static bool isOneUseSetCC(SDValue N) { 470 SDValue N0, N1, N2; 471 if (isSetCCEquivalent(N, N0, N1, N2) && N.getNode()->hasOneUse()) 472 return true; 473 return false; 474} 475 476SDValue DAGCombiner::ReassociateOps(unsigned Opc, SDValue N0, SDValue N1){ 477 MVT VT = N0.getValueType(); 478 // reassoc. (op (op x, c1), y) -> (op (op x, y), c1) iff x+c1 has one use 479 // reassoc. (op (op x, c1), c2) -> (op x, (op c1, c2)) 480 if (N0.getOpcode() == Opc && isa<ConstantSDNode>(N0.getOperand(1))) { 481 if (isa<ConstantSDNode>(N1)) { 482 SDValue OpNode = DAG.getNode(Opc, VT, N0.getOperand(1), N1); 483 AddToWorkList(OpNode.getNode()); 484 return DAG.getNode(Opc, VT, OpNode, N0.getOperand(0)); 485 } else if (N0.hasOneUse()) { 486 SDValue OpNode = DAG.getNode(Opc, VT, N0.getOperand(0), N1); 487 AddToWorkList(OpNode.getNode()); 488 return DAG.getNode(Opc, VT, OpNode, N0.getOperand(1)); 489 } 490 } 491 // reassoc. (op y, (op x, c1)) -> (op (op x, y), c1) iff x+c1 has one use 492 // reassoc. (op c2, (op x, c1)) -> (op x, (op c1, c2)) 493 if (N1.getOpcode() == Opc && isa<ConstantSDNode>(N1.getOperand(1))) { 494 if (isa<ConstantSDNode>(N0)) { 495 SDValue OpNode = DAG.getNode(Opc, VT, N1.getOperand(1), N0); 496 AddToWorkList(OpNode.getNode()); 497 return DAG.getNode(Opc, VT, OpNode, N1.getOperand(0)); 498 } else if (N1.hasOneUse()) { 499 SDValue OpNode = DAG.getNode(Opc, VT, N1.getOperand(0), N0); 500 AddToWorkList(OpNode.getNode()); 501 return DAG.getNode(Opc, VT, OpNode, N1.getOperand(1)); 502 } 503 } 504 return SDValue(); 505} 506 507SDValue DAGCombiner::CombineTo(SDNode *N, const SDValue *To, unsigned NumTo, 508 bool AddTo) { 509 assert(N->getNumValues() == NumTo && "Broken CombineTo call!"); 510 ++NodesCombined; 511 DOUT << "\nReplacing.1 "; DEBUG(N->dump(&DAG)); 512 DOUT << "\nWith: "; DEBUG(To[0].getNode()->dump(&DAG)); 513 DOUT << " and " << NumTo-1 << " other values\n"; 514 DEBUG(for (unsigned i = 0, e = NumTo; i != e; ++i) 515 assert(N->getValueType(i) == To[i].getValueType() && 516 "Cannot combine value to value of different type!")); 517 WorkListRemover DeadNodes(*this); 518 DAG.ReplaceAllUsesWith(N, To, &DeadNodes); 519 520 if (AddTo) { 521 // Push the new nodes and any users onto the worklist 522 for (unsigned i = 0, e = NumTo; i != e; ++i) { 523 AddToWorkList(To[i].getNode()); 524 AddUsersToWorkList(To[i].getNode()); 525 } 526 } 527 528 // Finally, if the node is now dead, remove it from the graph. The node 529 // may not be dead if the replacement process recursively simplified to 530 // something else needing this node. 531 if (N->use_empty()) { 532 // Nodes can be reintroduced into the worklist. Make sure we do not 533 // process a node that has been replaced. 534 removeFromWorkList(N); 535 536 // Finally, since the node is now dead, remove it from the graph. 537 DAG.DeleteNode(N); 538 } 539 return SDValue(N, 0); 540} 541 542/// SimplifyDemandedBits - Check the specified integer node value to see if 543/// it can be simplified or if things it uses can be simplified by bit 544/// propagation. If so, return true. 545bool DAGCombiner::SimplifyDemandedBits(SDValue Op, const APInt &Demanded) { 546 TargetLowering::TargetLoweringOpt TLO(DAG); 547 APInt KnownZero, KnownOne; 548 if (!TLI.SimplifyDemandedBits(Op, Demanded, KnownZero, KnownOne, TLO)) 549 return false; 550 551 // Revisit the node. 552 AddToWorkList(Op.getNode()); 553 554 // Replace the old value with the new one. 555 ++NodesCombined; 556 DOUT << "\nReplacing.2 "; DEBUG(TLO.Old.getNode()->dump(&DAG)); 557 DOUT << "\nWith: "; DEBUG(TLO.New.getNode()->dump(&DAG)); 558 DOUT << '\n'; 559 560 // Replace all uses. If any nodes become isomorphic to other nodes and 561 // are deleted, make sure to remove them from our worklist. 562 WorkListRemover DeadNodes(*this); 563 DAG.ReplaceAllUsesOfValueWith(TLO.Old, TLO.New, &DeadNodes); 564 565 // Push the new node and any (possibly new) users onto the worklist. 566 AddToWorkList(TLO.New.getNode()); 567 AddUsersToWorkList(TLO.New.getNode()); 568 569 // Finally, if the node is now dead, remove it from the graph. The node 570 // may not be dead if the replacement process recursively simplified to 571 // something else needing this node. 572 if (TLO.Old.getNode()->use_empty()) { 573 removeFromWorkList(TLO.Old.getNode()); 574 575 // If the operands of this node are only used by the node, they will now 576 // be dead. Make sure to visit them first to delete dead nodes early. 577 for (unsigned i = 0, e = TLO.Old.getNode()->getNumOperands(); i != e; ++i) 578 if (TLO.Old.getNode()->getOperand(i).getNode()->hasOneUse()) 579 AddToWorkList(TLO.Old.getNode()->getOperand(i).getNode()); 580 581 DAG.DeleteNode(TLO.Old.getNode()); 582 } 583 return true; 584} 585 586//===----------------------------------------------------------------------===// 587// Main DAG Combiner implementation 588//===----------------------------------------------------------------------===// 589 590void DAGCombiner::Run(CombineLevel AtLevel) { 591 // set the instance variables, so that the various visit routines may use it. 592 Level = AtLevel; 593 LegalOperations = Level >= NoIllegalOperations; 594 LegalTypes = Level >= NoIllegalTypes; 595 596 // Add all the dag nodes to the worklist. 597 WorkList.reserve(DAG.allnodes_size()); 598 for (SelectionDAG::allnodes_iterator I = DAG.allnodes_begin(), 599 E = DAG.allnodes_end(); I != E; ++I) 600 WorkList.push_back(I); 601 602 // Create a dummy node (which is not added to allnodes), that adds a reference 603 // to the root node, preventing it from being deleted, and tracking any 604 // changes of the root. 605 HandleSDNode Dummy(DAG.getRoot()); 606 607 // The root of the dag may dangle to deleted nodes until the dag combiner is 608 // done. Set it to null to avoid confusion. 609 DAG.setRoot(SDValue()); 610 611 // while the worklist isn't empty, inspect the node on the end of it and 612 // try and combine it. 613 while (!WorkList.empty()) { 614 SDNode *N = WorkList.back(); 615 WorkList.pop_back(); 616 617 // If N has no uses, it is dead. Make sure to revisit all N's operands once 618 // N is deleted from the DAG, since they too may now be dead or may have a 619 // reduced number of uses, allowing other xforms. 620 if (N->use_empty() && N != &Dummy) { 621 for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) 622 AddToWorkList(N->getOperand(i).getNode()); 623 624 DAG.DeleteNode(N); 625 continue; 626 } 627 628 SDValue RV = combine(N); 629 630 if (RV.getNode() == 0) 631 continue; 632 633 ++NodesCombined; 634 635 // If we get back the same node we passed in, rather than a new node or 636 // zero, we know that the node must have defined multiple values and 637 // CombineTo was used. Since CombineTo takes care of the worklist 638 // mechanics for us, we have no work to do in this case. 639 if (RV.getNode() == N) 640 continue; 641 642 assert(N->getOpcode() != ISD::DELETED_NODE && 643 RV.getNode()->getOpcode() != ISD::DELETED_NODE && 644 "Node was deleted but visit returned new node!"); 645 646 DOUT << "\nReplacing.3 "; DEBUG(N->dump(&DAG)); 647 DOUT << "\nWith: "; DEBUG(RV.getNode()->dump(&DAG)); 648 DOUT << '\n'; 649 WorkListRemover DeadNodes(*this); 650 if (N->getNumValues() == RV.getNode()->getNumValues()) 651 DAG.ReplaceAllUsesWith(N, RV.getNode(), &DeadNodes); 652 else { 653 assert(N->getValueType(0) == RV.getValueType() && 654 N->getNumValues() == 1 && "Type mismatch"); 655 SDValue OpV = RV; 656 DAG.ReplaceAllUsesWith(N, &OpV, &DeadNodes); 657 } 658 659 // Push the new node and any users onto the worklist 660 AddToWorkList(RV.getNode()); 661 AddUsersToWorkList(RV.getNode()); 662 663 // Add any uses of the old node to the worklist in case this node is the 664 // last one that uses them. They may become dead after this node is 665 // deleted. 666 for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) 667 AddToWorkList(N->getOperand(i).getNode()); 668 669 // Finally, if the node is now dead, remove it from the graph. The node 670 // may not be dead if the replacement process recursively simplified to 671 // something else needing this node. 672 if (N->use_empty()) { 673 // Nodes can be reintroduced into the worklist. Make sure we do not 674 // process a node that has been replaced. 675 removeFromWorkList(N); 676 677 // Finally, since the node is now dead, remove it from the graph. 678 DAG.DeleteNode(N); 679 } 680 } 681 682 // If the root changed (e.g. it was a dead load, update the root). 683 DAG.setRoot(Dummy.getValue()); 684} 685 686SDValue DAGCombiner::visit(SDNode *N) { 687 switch(N->getOpcode()) { 688 default: break; 689 case ISD::TokenFactor: return visitTokenFactor(N); 690 case ISD::MERGE_VALUES: return visitMERGE_VALUES(N); 691 case ISD::ADD: return visitADD(N); 692 case ISD::SUB: return visitSUB(N); 693 case ISD::ADDC: return visitADDC(N); 694 case ISD::ADDE: return visitADDE(N); 695 case ISD::MUL: return visitMUL(N); 696 case ISD::SDIV: return visitSDIV(N); 697 case ISD::UDIV: return visitUDIV(N); 698 case ISD::SREM: return visitSREM(N); 699 case ISD::UREM: return visitUREM(N); 700 case ISD::MULHU: return visitMULHU(N); 701 case ISD::MULHS: return visitMULHS(N); 702 case ISD::SMUL_LOHI: return visitSMUL_LOHI(N); 703 case ISD::UMUL_LOHI: return visitUMUL_LOHI(N); 704 case ISD::SDIVREM: return visitSDIVREM(N); 705 case ISD::UDIVREM: return visitUDIVREM(N); 706 case ISD::AND: return visitAND(N); 707 case ISD::OR: return visitOR(N); 708 case ISD::XOR: return visitXOR(N); 709 case ISD::SHL: return visitSHL(N); 710 case ISD::SRA: return visitSRA(N); 711 case ISD::SRL: return visitSRL(N); 712 case ISD::CTLZ: return visitCTLZ(N); 713 case ISD::CTTZ: return visitCTTZ(N); 714 case ISD::CTPOP: return visitCTPOP(N); 715 case ISD::SELECT: return visitSELECT(N); 716 case ISD::SELECT_CC: return visitSELECT_CC(N); 717 case ISD::SETCC: return visitSETCC(N); 718 case ISD::SIGN_EXTEND: return visitSIGN_EXTEND(N); 719 case ISD::ZERO_EXTEND: return visitZERO_EXTEND(N); 720 case ISD::ANY_EXTEND: return visitANY_EXTEND(N); 721 case ISD::SIGN_EXTEND_INREG: return visitSIGN_EXTEND_INREG(N); 722 case ISD::TRUNCATE: return visitTRUNCATE(N); 723 case ISD::BIT_CONVERT: return visitBIT_CONVERT(N); 724 case ISD::BUILD_PAIR: return visitBUILD_PAIR(N); 725 case ISD::FADD: return visitFADD(N); 726 case ISD::FSUB: return visitFSUB(N); 727 case ISD::FMUL: return visitFMUL(N); 728 case ISD::FDIV: return visitFDIV(N); 729 case ISD::FREM: return visitFREM(N); 730 case ISD::FCOPYSIGN: return visitFCOPYSIGN(N); 731 case ISD::SINT_TO_FP: return visitSINT_TO_FP(N); 732 case ISD::UINT_TO_FP: return visitUINT_TO_FP(N); 733 case ISD::FP_TO_SINT: return visitFP_TO_SINT(N); 734 case ISD::FP_TO_UINT: return visitFP_TO_UINT(N); 735 case ISD::FP_ROUND: return visitFP_ROUND(N); 736 case ISD::FP_ROUND_INREG: return visitFP_ROUND_INREG(N); 737 case ISD::FP_EXTEND: return visitFP_EXTEND(N); 738 case ISD::FNEG: return visitFNEG(N); 739 case ISD::FABS: return visitFABS(N); 740 case ISD::BRCOND: return visitBRCOND(N); 741 case ISD::BR_CC: return visitBR_CC(N); 742 case ISD::LOAD: return visitLOAD(N); 743 case ISD::STORE: return visitSTORE(N); 744 case ISD::INSERT_VECTOR_ELT: return visitINSERT_VECTOR_ELT(N); 745 case ISD::EXTRACT_VECTOR_ELT: return visitEXTRACT_VECTOR_ELT(N); 746 case ISD::BUILD_VECTOR: return visitBUILD_VECTOR(N); 747 case ISD::CONCAT_VECTORS: return visitCONCAT_VECTORS(N); 748 case ISD::VECTOR_SHUFFLE: return visitVECTOR_SHUFFLE(N); 749 } 750 return SDValue(); 751} 752 753SDValue DAGCombiner::combine(SDNode *N) { 754 755 SDValue RV = visit(N); 756 757 // If nothing happened, try a target-specific DAG combine. 758 if (RV.getNode() == 0) { 759 assert(N->getOpcode() != ISD::DELETED_NODE && 760 "Node was deleted but visit returned NULL!"); 761 762 if (N->getOpcode() >= ISD::BUILTIN_OP_END || 763 TLI.hasTargetDAGCombine((ISD::NodeType)N->getOpcode())) { 764 765 // Expose the DAG combiner to the target combiner impls. 766 TargetLowering::DAGCombinerInfo 767 DagCombineInfo(DAG, Level == Unrestricted, false, this); 768 769 RV = TLI.PerformDAGCombine(N, DagCombineInfo); 770 } 771 } 772 773 // If N is a commutative binary node, try commuting it to enable more 774 // sdisel CSE. 775 if (RV.getNode() == 0 && 776 SelectionDAG::isCommutativeBinOp(N->getOpcode()) && 777 N->getNumValues() == 1) { 778 SDValue N0 = N->getOperand(0); 779 SDValue N1 = N->getOperand(1); 780 // Constant operands are canonicalized to RHS. 781 if (isa<ConstantSDNode>(N0) || !isa<ConstantSDNode>(N1)) { 782 SDValue Ops[] = { N1, N0 }; 783 SDNode *CSENode = DAG.getNodeIfExists(N->getOpcode(), N->getVTList(), 784 Ops, 2); 785 if (CSENode) 786 return SDValue(CSENode, 0); 787 } 788 } 789 790 return RV; 791} 792 793/// getInputChainForNode - Given a node, return its input chain if it has one, 794/// otherwise return a null sd operand. 795static SDValue getInputChainForNode(SDNode *N) { 796 if (unsigned NumOps = N->getNumOperands()) { 797 if (N->getOperand(0).getValueType() == MVT::Other) 798 return N->getOperand(0); 799 else if (N->getOperand(NumOps-1).getValueType() == MVT::Other) 800 return N->getOperand(NumOps-1); 801 for (unsigned i = 1; i < NumOps-1; ++i) 802 if (N->getOperand(i).getValueType() == MVT::Other) 803 return N->getOperand(i); 804 } 805 return SDValue(0, 0); 806} 807 808SDValue DAGCombiner::visitTokenFactor(SDNode *N) { 809 // If N has two operands, where one has an input chain equal to the other, 810 // the 'other' chain is redundant. 811 if (N->getNumOperands() == 2) { 812 if (getInputChainForNode(N->getOperand(0).getNode()) == N->getOperand(1)) 813 return N->getOperand(0); 814 if (getInputChainForNode(N->getOperand(1).getNode()) == N->getOperand(0)) 815 return N->getOperand(1); 816 } 817 818 SmallVector<SDNode *, 8> TFs; // List of token factors to visit. 819 SmallVector<SDValue, 8> Ops; // Ops for replacing token factor. 820 SmallPtrSet<SDNode*, 16> SeenOps; 821 bool Changed = false; // If we should replace this token factor. 822 823 // Start out with this token factor. 824 TFs.push_back(N); 825 826 // Iterate through token factors. The TFs grows when new token factors are 827 // encountered. 828 for (unsigned i = 0; i < TFs.size(); ++i) { 829 SDNode *TF = TFs[i]; 830 831 // Check each of the operands. 832 for (unsigned i = 0, ie = TF->getNumOperands(); i != ie; ++i) { 833 SDValue Op = TF->getOperand(i); 834 835 switch (Op.getOpcode()) { 836 case ISD::EntryToken: 837 // Entry tokens don't need to be added to the list. They are 838 // rededundant. 839 Changed = true; 840 break; 841 842 case ISD::TokenFactor: 843 if ((CombinerAA || Op.hasOneUse()) && 844 std::find(TFs.begin(), TFs.end(), Op.getNode()) == TFs.end()) { 845 // Queue up for processing. 846 TFs.push_back(Op.getNode()); 847 // Clean up in case the token factor is removed. 848 AddToWorkList(Op.getNode()); 849 Changed = true; 850 break; 851 } 852 // Fall thru 853 854 default: 855 // Only add if it isn't already in the list. 856 if (SeenOps.insert(Op.getNode())) 857 Ops.push_back(Op); 858 else 859 Changed = true; 860 break; 861 } 862 } 863 } 864 865 SDValue Result; 866 867 // If we've change things around then replace token factor. 868 if (Changed) { 869 if (Ops.empty()) { 870 // The entry token is the only possible outcome. 871 Result = DAG.getEntryNode(); 872 } else { 873 // New and improved token factor. 874 Result = DAG.getNode(ISD::TokenFactor, MVT::Other, &Ops[0], Ops.size()); 875 } 876 877 // Don't add users to work list. 878 return CombineTo(N, Result, false); 879 } 880 881 return Result; 882} 883 884/// MERGE_VALUES can always be eliminated. 885SDValue DAGCombiner::visitMERGE_VALUES(SDNode *N) { 886 WorkListRemover DeadNodes(*this); 887 for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) 888 DAG.ReplaceAllUsesOfValueWith(SDValue(N, i), N->getOperand(i), 889 &DeadNodes); 890 removeFromWorkList(N); 891 DAG.DeleteNode(N); 892 return SDValue(N, 0); // Return N so it doesn't get rechecked! 893} 894 895 896static 897SDValue combineShlAddConstant(SDValue N0, SDValue N1, SelectionDAG &DAG) { 898 MVT VT = N0.getValueType(); 899 SDValue N00 = N0.getOperand(0); 900 SDValue N01 = N0.getOperand(1); 901 ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N01); 902 if (N01C && N00.getOpcode() == ISD::ADD && N00.getNode()->hasOneUse() && 903 isa<ConstantSDNode>(N00.getOperand(1))) { 904 N0 = DAG.getNode(ISD::ADD, VT, 905 DAG.getNode(ISD::SHL, VT, N00.getOperand(0), N01), 906 DAG.getNode(ISD::SHL, VT, N00.getOperand(1), N01)); 907 return DAG.getNode(ISD::ADD, VT, N0, N1); 908 } 909 return SDValue(); 910} 911 912static 913SDValue combineSelectAndUse(SDNode *N, SDValue Slct, SDValue OtherOp, 914 SelectionDAG &DAG, const TargetLowering &TLI, 915 bool LegalOperations) { 916 MVT VT = N->getValueType(0); 917 unsigned Opc = N->getOpcode(); 918 bool isSlctCC = Slct.getOpcode() == ISD::SELECT_CC; 919 SDValue LHS = isSlctCC ? Slct.getOperand(2) : Slct.getOperand(1); 920 SDValue RHS = isSlctCC ? Slct.getOperand(3) : Slct.getOperand(2); 921 ISD::CondCode CC = ISD::SETCC_INVALID; 922 923 if (isSlctCC) { 924 CC = cast<CondCodeSDNode>(Slct.getOperand(4))->get(); 925 } else { 926 SDValue CCOp = Slct.getOperand(0); 927 if (CCOp.getOpcode() == ISD::SETCC) 928 CC = cast<CondCodeSDNode>(CCOp.getOperand(2))->get(); 929 } 930 931 bool DoXform = false; 932 bool InvCC = false; 933 assert ((Opc == ISD::ADD || (Opc == ISD::SUB && Slct == N->getOperand(1))) && 934 "Bad input!"); 935 936 if (LHS.getOpcode() == ISD::Constant && 937 cast<ConstantSDNode>(LHS)->isNullValue()) { 938 DoXform = true; 939 } else if (CC != ISD::SETCC_INVALID && 940 RHS.getOpcode() == ISD::Constant && 941 cast<ConstantSDNode>(RHS)->isNullValue()) { 942 std::swap(LHS, RHS); 943 SDValue Op0 = Slct.getOperand(0); 944 MVT OpVT = isSlctCC ? Op0.getValueType() : 945 Op0.getOperand(0).getValueType(); 946 bool isInt = OpVT.isInteger(); 947 CC = ISD::getSetCCInverse(CC, isInt); 948 949 if (LegalOperations && !TLI.isCondCodeLegal(CC, OpVT)) 950 return SDValue(); // Inverse operator isn't legal. 951 952 DoXform = true; 953 InvCC = true; 954 } 955 956 if (DoXform) { 957 SDValue Result = DAG.getNode(Opc, VT, OtherOp, RHS); 958 if (isSlctCC) 959 return DAG.getSelectCC(OtherOp, Result, 960 Slct.getOperand(0), Slct.getOperand(1), CC); 961 SDValue CCOp = Slct.getOperand(0); 962 if (InvCC) 963 CCOp = DAG.getSetCC(CCOp.getValueType(), CCOp.getOperand(0), 964 CCOp.getOperand(1), CC); 965 return DAG.getNode(ISD::SELECT, VT, CCOp, OtherOp, Result); 966 } 967 return SDValue(); 968} 969 970SDValue DAGCombiner::visitADD(SDNode *N) { 971 SDValue N0 = N->getOperand(0); 972 SDValue N1 = N->getOperand(1); 973 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 974 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 975 MVT VT = N0.getValueType(); 976 977 // fold vector ops 978 if (VT.isVector()) { 979 SDValue FoldedVOp = SimplifyVBinOp(N); 980 if (FoldedVOp.getNode()) return FoldedVOp; 981 } 982 983 // fold (add x, undef) -> undef 984 if (N0.getOpcode() == ISD::UNDEF) 985 return N0; 986 if (N1.getOpcode() == ISD::UNDEF) 987 return N1; 988 // fold (add c1, c2) -> c1+c2 989 if (N0C && N1C) 990 return DAG.FoldConstantArithmetic(ISD::ADD, VT, N0C, N1C); 991 // canonicalize constant to RHS 992 if (N0C && !N1C) 993 return DAG.getNode(ISD::ADD, VT, N1, N0); 994 // fold (add x, 0) -> x 995 if (N1C && N1C->isNullValue()) 996 return N0; 997 // fold (add Sym, c) -> Sym+c 998 if (GlobalAddressSDNode *GA = dyn_cast<GlobalAddressSDNode>(N0)) 999 if (!LegalOperations && TLI.isOffsetFoldingLegal(GA) && N1C && 1000 GA->getOpcode() == ISD::GlobalAddress) 1001 return DAG.getGlobalAddress(GA->getGlobal(), VT, 1002 GA->getOffset() + 1003 (uint64_t)N1C->getSExtValue()); 1004 // fold ((c1-A)+c2) -> (c1+c2)-A 1005 if (N1C && N0.getOpcode() == ISD::SUB) 1006 if (ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.getOperand(0))) 1007 return DAG.getNode(ISD::SUB, VT, 1008 DAG.getConstant(N1C->getAPIntValue()+ 1009 N0C->getAPIntValue(), VT), 1010 N0.getOperand(1)); 1011 // reassociate add 1012 SDValue RADD = ReassociateOps(ISD::ADD, N0, N1); 1013 if (RADD.getNode() != 0) 1014 return RADD; 1015 // fold ((0-A) + B) -> B-A 1016 if (N0.getOpcode() == ISD::SUB && isa<ConstantSDNode>(N0.getOperand(0)) && 1017 cast<ConstantSDNode>(N0.getOperand(0))->isNullValue()) 1018 return DAG.getNode(ISD::SUB, VT, N1, N0.getOperand(1)); 1019 // fold (A + (0-B)) -> A-B 1020 if (N1.getOpcode() == ISD::SUB && isa<ConstantSDNode>(N1.getOperand(0)) && 1021 cast<ConstantSDNode>(N1.getOperand(0))->isNullValue()) 1022 return DAG.getNode(ISD::SUB, VT, N0, N1.getOperand(1)); 1023 // fold (A+(B-A)) -> B 1024 if (N1.getOpcode() == ISD::SUB && N0 == N1.getOperand(1)) 1025 return N1.getOperand(0); 1026 // fold ((B-A)+A) -> B 1027 if (N0.getOpcode() == ISD::SUB && N1 == N0.getOperand(1)) 1028 return N0.getOperand(0); 1029 // fold (A+(B-(A+C))) to (B-C) 1030 if (N1.getOpcode() == ISD::SUB && N1.getOperand(1).getOpcode() == ISD::ADD && 1031 N0 == N1.getOperand(1).getOperand(0)) { 1032 return DAG.getNode(ISD::SUB, VT, N1.getOperand(0), 1033 N1.getOperand(1).getOperand(1)); 1034 } 1035 // fold (A+(B-(C+A))) to (B-C) 1036 if (N1.getOpcode() == ISD::SUB && N1.getOperand(1).getOpcode() == ISD::ADD && 1037 N0 == N1.getOperand(1).getOperand(1)) { 1038 return DAG.getNode(ISD::SUB, VT, N1.getOperand(0), 1039 N1.getOperand(1).getOperand(0)); 1040 } 1041 // fold (A+((B-A)+or-C)) to (B+or-C) 1042 if ((N1.getOpcode() == ISD::SUB || N1.getOpcode() == ISD::ADD) && 1043 N1.getOperand(0).getOpcode() == ISD::SUB && 1044 N0 == N1.getOperand(0).getOperand(1)) { 1045 return DAG.getNode(N1.getOpcode(), VT, N1.getOperand(0).getOperand(0), 1046 N1.getOperand(1)); 1047 } 1048 1049 // fold (A-B)+(C-D) to (A+C)-(B+D) when A or C is constant 1050 if (N0.getOpcode() == ISD::SUB && N1.getOpcode() == ISD::SUB) { 1051 SDValue N00 = N0.getOperand(0); 1052 SDValue N01 = N0.getOperand(1); 1053 SDValue N10 = N1.getOperand(0); 1054 SDValue N11 = N1.getOperand(1); 1055 if (isa<ConstantSDNode>(N00) || isa<ConstantSDNode>(N10)) { 1056 return DAG.getNode(ISD::SUB, VT, 1057 DAG.getNode(ISD::ADD, VT, N00, N10), 1058 DAG.getNode(ISD::ADD, VT, N01, N11)); 1059 } 1060 } 1061 1062 if (!VT.isVector() && SimplifyDemandedBits(SDValue(N, 0))) 1063 return SDValue(N, 0); 1064 1065 // fold (a+b) -> (a|b) iff a and b share no bits. 1066 if (VT.isInteger() && !VT.isVector()) { 1067 APInt LHSZero, LHSOne; 1068 APInt RHSZero, RHSOne; 1069 APInt Mask = APInt::getAllOnesValue(VT.getSizeInBits()); 1070 DAG.ComputeMaskedBits(N0, Mask, LHSZero, LHSOne); 1071 if (LHSZero.getBoolValue()) { 1072 DAG.ComputeMaskedBits(N1, Mask, RHSZero, RHSOne); 1073 1074 // If all possibly-set bits on the LHS are clear on the RHS, return an OR. 1075 // If all possibly-set bits on the RHS are clear on the LHS, return an OR. 1076 if ((RHSZero & (~LHSZero & Mask)) == (~LHSZero & Mask) || 1077 (LHSZero & (~RHSZero & Mask)) == (~RHSZero & Mask)) 1078 return DAG.getNode(ISD::OR, VT, N0, N1); 1079 } 1080 } 1081 1082 // fold (add (shl (add x, c1), c2), ) -> (add (add (shl x, c2), c1<<c2), ) 1083 if (N0.getOpcode() == ISD::SHL && N0.getNode()->hasOneUse()) { 1084 SDValue Result = combineShlAddConstant(N0, N1, DAG); 1085 if (Result.getNode()) return Result; 1086 } 1087 if (N1.getOpcode() == ISD::SHL && N1.getNode()->hasOneUse()) { 1088 SDValue Result = combineShlAddConstant(N1, N0, DAG); 1089 if (Result.getNode()) return Result; 1090 } 1091 1092 // fold (add (select cc, 0, c), x) -> (select cc, x, (add, x, c)) 1093 if (N0.getOpcode() == ISD::SELECT && N0.getNode()->hasOneUse()) { 1094 SDValue Result = combineSelectAndUse(N, N0, N1, DAG, TLI, LegalOperations); 1095 if (Result.getNode()) return Result; 1096 } 1097 if (N1.getOpcode() == ISD::SELECT && N1.getNode()->hasOneUse()) { 1098 SDValue Result = combineSelectAndUse(N, N1, N0, DAG, TLI, LegalOperations); 1099 if (Result.getNode()) return Result; 1100 } 1101 1102 return SDValue(); 1103} 1104 1105SDValue DAGCombiner::visitADDC(SDNode *N) { 1106 SDValue N0 = N->getOperand(0); 1107 SDValue N1 = N->getOperand(1); 1108 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 1109 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1110 MVT VT = N0.getValueType(); 1111 1112 // If the flag result is dead, turn this into an ADD. 1113 if (N->hasNUsesOfValue(0, 1)) 1114 return CombineTo(N, DAG.getNode(ISD::ADD, VT, N1, N0), 1115 DAG.getNode(ISD::CARRY_FALSE, MVT::Flag)); 1116 1117 // canonicalize constant to RHS. 1118 if (N0C && !N1C) 1119 return DAG.getNode(ISD::ADDC, N->getVTList(), N1, N0); 1120 1121 // fold (addc x, 0) -> x + no carry out 1122 if (N1C && N1C->isNullValue()) 1123 return CombineTo(N, N0, DAG.getNode(ISD::CARRY_FALSE, MVT::Flag)); 1124 1125 // fold (addc a, b) -> (or a, b), CARRY_FALSE iff a and b share no bits. 1126 APInt LHSZero, LHSOne; 1127 APInt RHSZero, RHSOne; 1128 APInt Mask = APInt::getAllOnesValue(VT.getSizeInBits()); 1129 DAG.ComputeMaskedBits(N0, Mask, LHSZero, LHSOne); 1130 if (LHSZero.getBoolValue()) { 1131 DAG.ComputeMaskedBits(N1, Mask, RHSZero, RHSOne); 1132 1133 // If all possibly-set bits on the LHS are clear on the RHS, return an OR. 1134 // If all possibly-set bits on the RHS are clear on the LHS, return an OR. 1135 if ((RHSZero & (~LHSZero & Mask)) == (~LHSZero & Mask) || 1136 (LHSZero & (~RHSZero & Mask)) == (~RHSZero & Mask)) 1137 return CombineTo(N, DAG.getNode(ISD::OR, VT, N0, N1), 1138 DAG.getNode(ISD::CARRY_FALSE, MVT::Flag)); 1139 } 1140 1141 return SDValue(); 1142} 1143 1144SDValue DAGCombiner::visitADDE(SDNode *N) { 1145 SDValue N0 = N->getOperand(0); 1146 SDValue N1 = N->getOperand(1); 1147 SDValue CarryIn = N->getOperand(2); 1148 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 1149 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1150 //MVT VT = N0.getValueType(); 1151 1152 // canonicalize constant to RHS 1153 if (N0C && !N1C) 1154 return DAG.getNode(ISD::ADDE, N->getVTList(), N1, N0, CarryIn); 1155 1156 // fold (adde x, y, false) -> (addc x, y) 1157 if (CarryIn.getOpcode() == ISD::CARRY_FALSE) 1158 return DAG.getNode(ISD::ADDC, N->getVTList(), N1, N0); 1159 1160 return SDValue(); 1161} 1162 1163 1164 1165SDValue DAGCombiner::visitSUB(SDNode *N) { 1166 SDValue N0 = N->getOperand(0); 1167 SDValue N1 = N->getOperand(1); 1168 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.getNode()); 1169 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.getNode()); 1170 MVT VT = N0.getValueType(); 1171 1172 // fold vector ops 1173 if (VT.isVector()) { 1174 SDValue FoldedVOp = SimplifyVBinOp(N); 1175 if (FoldedVOp.getNode()) return FoldedVOp; 1176 } 1177 1178 // fold (sub x, x) -> 0 1179 if (N0 == N1) 1180 return DAG.getConstant(0, N->getValueType(0)); 1181 // fold (sub c1, c2) -> c1-c2 1182 if (N0C && N1C) 1183 return DAG.FoldConstantArithmetic(ISD::SUB, VT, N0C, N1C); 1184 // fold (sub x, c) -> (add x, -c) 1185 if (N1C) 1186 return DAG.getNode(ISD::ADD, VT, N0, 1187 DAG.getConstant(-N1C->getAPIntValue(), VT)); 1188 // fold (A+B)-A -> B 1189 if (N0.getOpcode() == ISD::ADD && N0.getOperand(0) == N1) 1190 return N0.getOperand(1); 1191 // fold (A+B)-B -> A 1192 if (N0.getOpcode() == ISD::ADD && N0.getOperand(1) == N1) 1193 return N0.getOperand(0); 1194 // fold ((A+(B+or-C))-B) -> A+or-C 1195 if (N0.getOpcode() == ISD::ADD && 1196 (N0.getOperand(1).getOpcode() == ISD::SUB || 1197 N0.getOperand(1).getOpcode() == ISD::ADD) && 1198 N0.getOperand(1).getOperand(0) == N1) 1199 return DAG.getNode(N0.getOperand(1).getOpcode(), VT, N0.getOperand(0), 1200 N0.getOperand(1).getOperand(1)); 1201 // fold ((A+(C+B))-B) -> A+C 1202 if (N0.getOpcode() == ISD::ADD && 1203 N0.getOperand(1).getOpcode() == ISD::ADD && 1204 N0.getOperand(1).getOperand(1) == N1) 1205 return DAG.getNode(ISD::ADD, VT, N0.getOperand(0), 1206 N0.getOperand(1).getOperand(0)); 1207 // fold ((A-(B-C))-C) -> A-B 1208 if (N0.getOpcode() == ISD::SUB && 1209 N0.getOperand(1).getOpcode() == ISD::SUB && 1210 N0.getOperand(1).getOperand(1) == N1) 1211 return DAG.getNode(ISD::SUB, VT, N0.getOperand(0), 1212 N0.getOperand(1).getOperand(0)); 1213 // fold (sub x, (select cc, 0, c)) -> (select cc, x, (sub, x, c)) 1214 if (N1.getOpcode() == ISD::SELECT && N1.getNode()->hasOneUse()) { 1215 SDValue Result = combineSelectAndUse(N, N1, N0, DAG, TLI, LegalOperations); 1216 if (Result.getNode()) return Result; 1217 } 1218 // If either operand of a sub is undef, the result is undef 1219 if (N0.getOpcode() == ISD::UNDEF) 1220 return N0; 1221 if (N1.getOpcode() == ISD::UNDEF) 1222 return N1; 1223 1224 // If the relocation model supports it, consider symbol offsets. 1225 if (GlobalAddressSDNode *GA = dyn_cast<GlobalAddressSDNode>(N0)) 1226 if (!LegalOperations && TLI.isOffsetFoldingLegal(GA)) { 1227 // fold (sub Sym, c) -> Sym-c 1228 if (N1C && GA->getOpcode() == ISD::GlobalAddress) 1229 return DAG.getGlobalAddress(GA->getGlobal(), VT, 1230 GA->getOffset() - 1231 (uint64_t)N1C->getSExtValue()); 1232 // fold (sub Sym+c1, Sym+c2) -> c1-c2 1233 if (GlobalAddressSDNode *GB = dyn_cast<GlobalAddressSDNode>(N1)) 1234 if (GA->getGlobal() == GB->getGlobal()) 1235 return DAG.getConstant((uint64_t)GA->getOffset() - GB->getOffset(), 1236 VT); 1237 } 1238 1239 return SDValue(); 1240} 1241 1242SDValue DAGCombiner::visitMUL(SDNode *N) { 1243 SDValue N0 = N->getOperand(0); 1244 SDValue N1 = N->getOperand(1); 1245 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 1246 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1247 MVT VT = N0.getValueType(); 1248 1249 // fold vector ops 1250 if (VT.isVector()) { 1251 SDValue FoldedVOp = SimplifyVBinOp(N); 1252 if (FoldedVOp.getNode()) return FoldedVOp; 1253 } 1254 1255 // fold (mul x, undef) -> 0 1256 if (N0.getOpcode() == ISD::UNDEF || N1.getOpcode() == ISD::UNDEF) 1257 return DAG.getConstant(0, VT); 1258 // fold (mul c1, c2) -> c1*c2 1259 if (N0C && N1C) 1260 return DAG.FoldConstantArithmetic(ISD::MUL, VT, N0C, N1C); 1261 // canonicalize constant to RHS 1262 if (N0C && !N1C) 1263 return DAG.getNode(ISD::MUL, VT, N1, N0); 1264 // fold (mul x, 0) -> 0 1265 if (N1C && N1C->isNullValue()) 1266 return N1; 1267 // fold (mul x, -1) -> 0-x 1268 if (N1C && N1C->isAllOnesValue()) 1269 return DAG.getNode(ISD::SUB, VT, DAG.getConstant(0, VT), N0); 1270 // fold (mul x, (1 << c)) -> x << c 1271 if (N1C && N1C->getAPIntValue().isPowerOf2()) 1272 return DAG.getNode(ISD::SHL, VT, N0, 1273 DAG.getConstant(N1C->getAPIntValue().logBase2(), 1274 TLI.getShiftAmountTy())); 1275 // fold (mul x, -(1 << c)) -> -(x << c) or (-x) << c 1276 if (N1C && isPowerOf2_64(-N1C->getSExtValue())) { 1277 // FIXME: If the input is something that is easily negated (e.g. a 1278 // single-use add), we should put the negate there. 1279 return DAG.getNode(ISD::SUB, VT, DAG.getConstant(0, VT), 1280 DAG.getNode(ISD::SHL, VT, N0, 1281 DAG.getConstant(Log2_64(-N1C->getSExtValue()), 1282 TLI.getShiftAmountTy()))); 1283 } 1284 1285 // (mul (shl X, c1), c2) -> (mul X, c2 << c1) 1286 if (N1C && N0.getOpcode() == ISD::SHL && 1287 isa<ConstantSDNode>(N0.getOperand(1))) { 1288 SDValue C3 = DAG.getNode(ISD::SHL, VT, N1, N0.getOperand(1)); 1289 AddToWorkList(C3.getNode()); 1290 return DAG.getNode(ISD::MUL, VT, N0.getOperand(0), C3); 1291 } 1292 1293 // Change (mul (shl X, C), Y) -> (shl (mul X, Y), C) when the shift has one 1294 // use. 1295 { 1296 SDValue Sh(0,0), Y(0,0); 1297 // Check for both (mul (shl X, C), Y) and (mul Y, (shl X, C)). 1298 if (N0.getOpcode() == ISD::SHL && isa<ConstantSDNode>(N0.getOperand(1)) && 1299 N0.getNode()->hasOneUse()) { 1300 Sh = N0; Y = N1; 1301 } else if (N1.getOpcode() == ISD::SHL && 1302 isa<ConstantSDNode>(N1.getOperand(1)) && 1303 N1.getNode()->hasOneUse()) { 1304 Sh = N1; Y = N0; 1305 } 1306 if (Sh.getNode()) { 1307 SDValue Mul = DAG.getNode(ISD::MUL, VT, Sh.getOperand(0), Y); 1308 return DAG.getNode(ISD::SHL, VT, Mul, Sh.getOperand(1)); 1309 } 1310 } 1311 // fold (mul (add x, c1), c2) -> (add (mul x, c2), c1*c2) 1312 if (N1C && N0.getOpcode() == ISD::ADD && N0.getNode()->hasOneUse() && 1313 isa<ConstantSDNode>(N0.getOperand(1))) { 1314 return DAG.getNode(ISD::ADD, VT, 1315 DAG.getNode(ISD::MUL, VT, N0.getOperand(0), N1), 1316 DAG.getNode(ISD::MUL, VT, N0.getOperand(1), N1)); 1317 } 1318 1319 // reassociate mul 1320 SDValue RMUL = ReassociateOps(ISD::MUL, N0, N1); 1321 if (RMUL.getNode() != 0) 1322 return RMUL; 1323 1324 return SDValue(); 1325} 1326 1327SDValue DAGCombiner::visitSDIV(SDNode *N) { 1328 SDValue N0 = N->getOperand(0); 1329 SDValue N1 = N->getOperand(1); 1330 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.getNode()); 1331 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.getNode()); 1332 MVT VT = N->getValueType(0); 1333 1334 // fold vector ops 1335 if (VT.isVector()) { 1336 SDValue FoldedVOp = SimplifyVBinOp(N); 1337 if (FoldedVOp.getNode()) return FoldedVOp; 1338 } 1339 1340 // fold (sdiv c1, c2) -> c1/c2 1341 if (N0C && N1C && !N1C->isNullValue()) 1342 return DAG.FoldConstantArithmetic(ISD::SDIV, VT, N0C, N1C); 1343 // fold (sdiv X, 1) -> X 1344 if (N1C && N1C->getSExtValue() == 1LL) 1345 return N0; 1346 // fold (sdiv X, -1) -> 0-X 1347 if (N1C && N1C->isAllOnesValue()) 1348 return DAG.getNode(ISD::SUB, VT, DAG.getConstant(0, VT), N0); 1349 // If we know the sign bits of both operands are zero, strength reduce to a 1350 // udiv instead. Handles (X&15) /s 4 -> X&15 >> 2 1351 if (!VT.isVector()) { 1352 if (DAG.SignBitIsZero(N1) && DAG.SignBitIsZero(N0)) 1353 return DAG.getNode(ISD::UDIV, N1.getValueType(), N0, N1); 1354 } 1355 // fold (sdiv X, pow2) -> simple ops after legalize 1356 if (N1C && !N1C->isNullValue() && !TLI.isIntDivCheap() && 1357 (isPowerOf2_64(N1C->getSExtValue()) || 1358 isPowerOf2_64(-N1C->getSExtValue()))) { 1359 // If dividing by powers of two is cheap, then don't perform the following 1360 // fold. 1361 if (TLI.isPow2DivCheap()) 1362 return SDValue(); 1363 int64_t pow2 = N1C->getSExtValue(); 1364 int64_t abs2 = pow2 > 0 ? pow2 : -pow2; 1365 unsigned lg2 = Log2_64(abs2); 1366 // Splat the sign bit into the register 1367 SDValue SGN = DAG.getNode(ISD::SRA, VT, N0, 1368 DAG.getConstant(VT.getSizeInBits()-1, 1369 TLI.getShiftAmountTy())); 1370 AddToWorkList(SGN.getNode()); 1371 // Add (N0 < 0) ? abs2 - 1 : 0; 1372 SDValue SRL = DAG.getNode(ISD::SRL, VT, SGN, 1373 DAG.getConstant(VT.getSizeInBits()-lg2, 1374 TLI.getShiftAmountTy())); 1375 SDValue ADD = DAG.getNode(ISD::ADD, VT, N0, SRL); 1376 AddToWorkList(SRL.getNode()); 1377 AddToWorkList(ADD.getNode()); // Divide by pow2 1378 SDValue SRA = DAG.getNode(ISD::SRA, VT, ADD, 1379 DAG.getConstant(lg2, TLI.getShiftAmountTy())); 1380 // If we're dividing by a positive value, we're done. Otherwise, we must 1381 // negate the result. 1382 if (pow2 > 0) 1383 return SRA; 1384 AddToWorkList(SRA.getNode()); 1385 return DAG.getNode(ISD::SUB, VT, DAG.getConstant(0, VT), SRA); 1386 } 1387 // if integer divide is expensive and we satisfy the requirements, emit an 1388 // alternate sequence. 1389 if (N1C && (N1C->getSExtValue() < -1 || N1C->getSExtValue() > 1) && 1390 !TLI.isIntDivCheap()) { 1391 SDValue Op = BuildSDIV(N); 1392 if (Op.getNode()) return Op; 1393 } 1394 1395 // undef / X -> 0 1396 if (N0.getOpcode() == ISD::UNDEF) 1397 return DAG.getConstant(0, VT); 1398 // X / undef -> undef 1399 if (N1.getOpcode() == ISD::UNDEF) 1400 return N1; 1401 1402 return SDValue(); 1403} 1404 1405SDValue DAGCombiner::visitUDIV(SDNode *N) { 1406 SDValue N0 = N->getOperand(0); 1407 SDValue N1 = N->getOperand(1); 1408 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.getNode()); 1409 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.getNode()); 1410 MVT VT = N->getValueType(0); 1411 1412 // fold vector ops 1413 if (VT.isVector()) { 1414 SDValue FoldedVOp = SimplifyVBinOp(N); 1415 if (FoldedVOp.getNode()) return FoldedVOp; 1416 } 1417 1418 // fold (udiv c1, c2) -> c1/c2 1419 if (N0C && N1C && !N1C->isNullValue()) 1420 return DAG.FoldConstantArithmetic(ISD::UDIV, VT, N0C, N1C); 1421 // fold (udiv x, (1 << c)) -> x >>u c 1422 if (N1C && N1C->getAPIntValue().isPowerOf2()) 1423 return DAG.getNode(ISD::SRL, VT, N0, 1424 DAG.getConstant(N1C->getAPIntValue().logBase2(), 1425 TLI.getShiftAmountTy())); 1426 // fold (udiv x, (shl c, y)) -> x >>u (log2(c)+y) iff c is power of 2 1427 if (N1.getOpcode() == ISD::SHL) { 1428 if (ConstantSDNode *SHC = dyn_cast<ConstantSDNode>(N1.getOperand(0))) { 1429 if (SHC->getAPIntValue().isPowerOf2()) { 1430 MVT ADDVT = N1.getOperand(1).getValueType(); 1431 SDValue Add = DAG.getNode(ISD::ADD, ADDVT, N1.getOperand(1), 1432 DAG.getConstant(SHC->getAPIntValue() 1433 .logBase2(), 1434 ADDVT)); 1435 AddToWorkList(Add.getNode()); 1436 return DAG.getNode(ISD::SRL, VT, N0, Add); 1437 } 1438 } 1439 } 1440 // fold (udiv x, c) -> alternate 1441 if (N1C && !N1C->isNullValue() && !TLI.isIntDivCheap()) { 1442 SDValue Op = BuildUDIV(N); 1443 if (Op.getNode()) return Op; 1444 } 1445 1446 // undef / X -> 0 1447 if (N0.getOpcode() == ISD::UNDEF) 1448 return DAG.getConstant(0, VT); 1449 // X / undef -> undef 1450 if (N1.getOpcode() == ISD::UNDEF) 1451 return N1; 1452 1453 return SDValue(); 1454} 1455 1456SDValue DAGCombiner::visitSREM(SDNode *N) { 1457 SDValue N0 = N->getOperand(0); 1458 SDValue N1 = N->getOperand(1); 1459 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 1460 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1461 MVT VT = N->getValueType(0); 1462 1463 // fold (srem c1, c2) -> c1%c2 1464 if (N0C && N1C && !N1C->isNullValue()) 1465 return DAG.FoldConstantArithmetic(ISD::SREM, VT, N0C, N1C); 1466 // If we know the sign bits of both operands are zero, strength reduce to a 1467 // urem instead. Handles (X & 0x0FFFFFFF) %s 16 -> X&15 1468 if (!VT.isVector()) { 1469 if (DAG.SignBitIsZero(N1) && DAG.SignBitIsZero(N0)) 1470 return DAG.getNode(ISD::UREM, VT, N0, N1); 1471 } 1472 1473 // If X/C can be simplified by the division-by-constant logic, lower 1474 // X%C to the equivalent of X-X/C*C. 1475 if (N1C && !N1C->isNullValue()) { 1476 SDValue Div = DAG.getNode(ISD::SDIV, VT, N0, N1); 1477 AddToWorkList(Div.getNode()); 1478 SDValue OptimizedDiv = combine(Div.getNode()); 1479 if (OptimizedDiv.getNode() && OptimizedDiv.getNode() != Div.getNode()) { 1480 SDValue Mul = DAG.getNode(ISD::MUL, VT, OptimizedDiv, N1); 1481 SDValue Sub = DAG.getNode(ISD::SUB, VT, N0, Mul); 1482 AddToWorkList(Mul.getNode()); 1483 return Sub; 1484 } 1485 } 1486 1487 // undef % X -> 0 1488 if (N0.getOpcode() == ISD::UNDEF) 1489 return DAG.getConstant(0, VT); 1490 // X % undef -> undef 1491 if (N1.getOpcode() == ISD::UNDEF) 1492 return N1; 1493 1494 return SDValue(); 1495} 1496 1497SDValue DAGCombiner::visitUREM(SDNode *N) { 1498 SDValue N0 = N->getOperand(0); 1499 SDValue N1 = N->getOperand(1); 1500 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 1501 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1502 MVT VT = N->getValueType(0); 1503 1504 // fold (urem c1, c2) -> c1%c2 1505 if (N0C && N1C && !N1C->isNullValue()) 1506 return DAG.FoldConstantArithmetic(ISD::UREM, VT, N0C, N1C); 1507 // fold (urem x, pow2) -> (and x, pow2-1) 1508 if (N1C && !N1C->isNullValue() && N1C->getAPIntValue().isPowerOf2()) 1509 return DAG.getNode(ISD::AND, VT, N0, 1510 DAG.getConstant(N1C->getAPIntValue()-1,VT)); 1511 // fold (urem x, (shl pow2, y)) -> (and x, (add (shl pow2, y), -1)) 1512 if (N1.getOpcode() == ISD::SHL) { 1513 if (ConstantSDNode *SHC = dyn_cast<ConstantSDNode>(N1.getOperand(0))) { 1514 if (SHC->getAPIntValue().isPowerOf2()) { 1515 SDValue Add = 1516 DAG.getNode(ISD::ADD, VT, N1, 1517 DAG.getConstant(APInt::getAllOnesValue(VT.getSizeInBits()), 1518 VT)); 1519 AddToWorkList(Add.getNode()); 1520 return DAG.getNode(ISD::AND, VT, N0, Add); 1521 } 1522 } 1523 } 1524 1525 // If X/C can be simplified by the division-by-constant logic, lower 1526 // X%C to the equivalent of X-X/C*C. 1527 if (N1C && !N1C->isNullValue()) { 1528 SDValue Div = DAG.getNode(ISD::UDIV, VT, N0, N1); 1529 AddToWorkList(Div.getNode()); 1530 SDValue OptimizedDiv = combine(Div.getNode()); 1531 if (OptimizedDiv.getNode() && OptimizedDiv.getNode() != Div.getNode()) { 1532 SDValue Mul = DAG.getNode(ISD::MUL, VT, OptimizedDiv, N1); 1533 SDValue Sub = DAG.getNode(ISD::SUB, VT, N0, Mul); 1534 AddToWorkList(Mul.getNode()); 1535 return Sub; 1536 } 1537 } 1538 1539 // undef % X -> 0 1540 if (N0.getOpcode() == ISD::UNDEF) 1541 return DAG.getConstant(0, VT); 1542 // X % undef -> undef 1543 if (N1.getOpcode() == ISD::UNDEF) 1544 return N1; 1545 1546 return SDValue(); 1547} 1548 1549SDValue DAGCombiner::visitMULHS(SDNode *N) { 1550 SDValue N0 = N->getOperand(0); 1551 SDValue N1 = N->getOperand(1); 1552 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1553 MVT VT = N->getValueType(0); 1554 1555 // fold (mulhs x, 0) -> 0 1556 if (N1C && N1C->isNullValue()) 1557 return N1; 1558 // fold (mulhs x, 1) -> (sra x, size(x)-1) 1559 if (N1C && N1C->getAPIntValue() == 1) 1560 return DAG.getNode(ISD::SRA, N0.getValueType(), N0, 1561 DAG.getConstant(N0.getValueType().getSizeInBits()-1, 1562 TLI.getShiftAmountTy())); 1563 // fold (mulhs x, undef) -> 0 1564 if (N0.getOpcode() == ISD::UNDEF || N1.getOpcode() == ISD::UNDEF) 1565 return DAG.getConstant(0, VT); 1566 1567 return SDValue(); 1568} 1569 1570SDValue DAGCombiner::visitMULHU(SDNode *N) { 1571 SDValue N0 = N->getOperand(0); 1572 SDValue N1 = N->getOperand(1); 1573 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1574 MVT VT = N->getValueType(0); 1575 1576 // fold (mulhu x, 0) -> 0 1577 if (N1C && N1C->isNullValue()) 1578 return N1; 1579 // fold (mulhu x, 1) -> 0 1580 if (N1C && N1C->getAPIntValue() == 1) 1581 return DAG.getConstant(0, N0.getValueType()); 1582 // fold (mulhu x, undef) -> 0 1583 if (N0.getOpcode() == ISD::UNDEF || N1.getOpcode() == ISD::UNDEF) 1584 return DAG.getConstant(0, VT); 1585 1586 return SDValue(); 1587} 1588 1589/// SimplifyNodeWithTwoResults - Perform optimizations common to nodes that 1590/// compute two values. LoOp and HiOp give the opcodes for the two computations 1591/// that are being performed. Return true if a simplification was made. 1592/// 1593SDValue DAGCombiner::SimplifyNodeWithTwoResults(SDNode *N, unsigned LoOp, 1594 unsigned HiOp) { 1595 // If the high half is not needed, just compute the low half. 1596 bool HiExists = N->hasAnyUseOfValue(1); 1597 if (!HiExists && 1598 (!LegalOperations || 1599 TLI.isOperationLegal(LoOp, N->getValueType(0)))) { 1600 SDValue Res = DAG.getNode(LoOp, N->getValueType(0), N->op_begin(), 1601 N->getNumOperands()); 1602 return CombineTo(N, Res, Res); 1603 } 1604 1605 // If the low half is not needed, just compute the high half. 1606 bool LoExists = N->hasAnyUseOfValue(0); 1607 if (!LoExists && 1608 (!LegalOperations || 1609 TLI.isOperationLegal(HiOp, N->getValueType(1)))) { 1610 SDValue Res = DAG.getNode(HiOp, N->getValueType(1), N->op_begin(), 1611 N->getNumOperands()); 1612 return CombineTo(N, Res, Res); 1613 } 1614 1615 // If both halves are used, return as it is. 1616 if (LoExists && HiExists) 1617 return SDValue(); 1618 1619 // If the two computed results can be simplified separately, separate them. 1620 if (LoExists) { 1621 SDValue Lo = DAG.getNode(LoOp, N->getValueType(0), 1622 N->op_begin(), N->getNumOperands()); 1623 AddToWorkList(Lo.getNode()); 1624 SDValue LoOpt = combine(Lo.getNode()); 1625 if (LoOpt.getNode() && LoOpt.getNode() != Lo.getNode() && 1626 (!LegalOperations || 1627 TLI.isOperationLegal(LoOpt.getOpcode(), LoOpt.getValueType()))) 1628 return CombineTo(N, LoOpt, LoOpt); 1629 } 1630 1631 if (HiExists) { 1632 SDValue Hi = DAG.getNode(HiOp, N->getValueType(1), 1633 N->op_begin(), N->getNumOperands()); 1634 AddToWorkList(Hi.getNode()); 1635 SDValue HiOpt = combine(Hi.getNode()); 1636 if (HiOpt.getNode() && HiOpt != Hi && 1637 (!LegalOperations || 1638 TLI.isOperationLegal(HiOpt.getOpcode(), HiOpt.getValueType()))) 1639 return CombineTo(N, HiOpt, HiOpt); 1640 } 1641 return SDValue(); 1642} 1643 1644SDValue DAGCombiner::visitSMUL_LOHI(SDNode *N) { 1645 SDValue Res = SimplifyNodeWithTwoResults(N, ISD::MUL, ISD::MULHS); 1646 if (Res.getNode()) return Res; 1647 1648 return SDValue(); 1649} 1650 1651SDValue DAGCombiner::visitUMUL_LOHI(SDNode *N) { 1652 SDValue Res = SimplifyNodeWithTwoResults(N, ISD::MUL, ISD::MULHU); 1653 if (Res.getNode()) return Res; 1654 1655 return SDValue(); 1656} 1657 1658SDValue DAGCombiner::visitSDIVREM(SDNode *N) { 1659 SDValue Res = SimplifyNodeWithTwoResults(N, ISD::SDIV, ISD::SREM); 1660 if (Res.getNode()) return Res; 1661 1662 return SDValue(); 1663} 1664 1665SDValue DAGCombiner::visitUDIVREM(SDNode *N) { 1666 SDValue Res = SimplifyNodeWithTwoResults(N, ISD::UDIV, ISD::UREM); 1667 if (Res.getNode()) return Res; 1668 1669 return SDValue(); 1670} 1671 1672/// SimplifyBinOpWithSameOpcodeHands - If this is a binary operator with 1673/// two operands of the same opcode, try to simplify it. 1674SDValue DAGCombiner::SimplifyBinOpWithSameOpcodeHands(SDNode *N) { 1675 SDValue N0 = N->getOperand(0), N1 = N->getOperand(1); 1676 MVT VT = N0.getValueType(); 1677 assert(N0.getOpcode() == N1.getOpcode() && "Bad input!"); 1678 1679 // For each of OP in AND/OR/XOR: 1680 // fold (OP (zext x), (zext y)) -> (zext (OP x, y)) 1681 // fold (OP (sext x), (sext y)) -> (sext (OP x, y)) 1682 // fold (OP (aext x), (aext y)) -> (aext (OP x, y)) 1683 // fold (OP (trunc x), (trunc y)) -> (trunc (OP x, y)) 1684 if ((N0.getOpcode() == ISD::ZERO_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND|| 1685 N0.getOpcode() == ISD::SIGN_EXTEND || N0.getOpcode() == ISD::TRUNCATE) && 1686 N0.getOperand(0).getValueType() == N1.getOperand(0).getValueType()) { 1687 SDValue ORNode = DAG.getNode(N->getOpcode(), 1688 N0.getOperand(0).getValueType(), 1689 N0.getOperand(0), N1.getOperand(0)); 1690 AddToWorkList(ORNode.getNode()); 1691 return DAG.getNode(N0.getOpcode(), VT, ORNode); 1692 } 1693 1694 // For each of OP in SHL/SRL/SRA/AND... 1695 // fold (and (OP x, z), (OP y, z)) -> (OP (and x, y), z) 1696 // fold (or (OP x, z), (OP y, z)) -> (OP (or x, y), z) 1697 // fold (xor (OP x, z), (OP y, z)) -> (OP (xor x, y), z) 1698 if ((N0.getOpcode() == ISD::SHL || N0.getOpcode() == ISD::SRL || 1699 N0.getOpcode() == ISD::SRA || N0.getOpcode() == ISD::AND) && 1700 N0.getOperand(1) == N1.getOperand(1)) { 1701 SDValue ORNode = DAG.getNode(N->getOpcode(), 1702 N0.getOperand(0).getValueType(), 1703 N0.getOperand(0), N1.getOperand(0)); 1704 AddToWorkList(ORNode.getNode()); 1705 return DAG.getNode(N0.getOpcode(), VT, ORNode, N0.getOperand(1)); 1706 } 1707 1708 return SDValue(); 1709} 1710 1711SDValue DAGCombiner::visitAND(SDNode *N) { 1712 SDValue N0 = N->getOperand(0); 1713 SDValue N1 = N->getOperand(1); 1714 SDValue LL, LR, RL, RR, CC0, CC1; 1715 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 1716 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1717 MVT VT = N1.getValueType(); 1718 unsigned BitWidth = VT.getSizeInBits(); 1719 1720 // fold vector ops 1721 if (VT.isVector()) { 1722 SDValue FoldedVOp = SimplifyVBinOp(N); 1723 if (FoldedVOp.getNode()) return FoldedVOp; 1724 } 1725 1726 // fold (and x, undef) -> 0 1727 if (N0.getOpcode() == ISD::UNDEF || N1.getOpcode() == ISD::UNDEF) 1728 return DAG.getConstant(0, VT); 1729 // fold (and c1, c2) -> c1&c2 1730 if (N0C && N1C) 1731 return DAG.FoldConstantArithmetic(ISD::AND, VT, N0C, N1C); 1732 // canonicalize constant to RHS 1733 if (N0C && !N1C) 1734 return DAG.getNode(ISD::AND, VT, N1, N0); 1735 // fold (and x, -1) -> x 1736 if (N1C && N1C->isAllOnesValue()) 1737 return N0; 1738 // if (and x, c) is known to be zero, return 0 1739 if (N1C && DAG.MaskedValueIsZero(SDValue(N, 0), 1740 APInt::getAllOnesValue(BitWidth))) 1741 return DAG.getConstant(0, VT); 1742 // reassociate and 1743 SDValue RAND = ReassociateOps(ISD::AND, N0, N1); 1744 if (RAND.getNode() != 0) 1745 return RAND; 1746 // fold (and (or x, 0xFFFF), 0xFF) -> 0xFF 1747 if (N1C && N0.getOpcode() == ISD::OR) 1748 if (ConstantSDNode *ORI = dyn_cast<ConstantSDNode>(N0.getOperand(1))) 1749 if ((ORI->getAPIntValue() & N1C->getAPIntValue()) == N1C->getAPIntValue()) 1750 return N1; 1751 // fold (and (any_ext V), c) -> (zero_ext V) if 'and' only clears top bits. 1752 if (N1C && N0.getOpcode() == ISD::ANY_EXTEND) { 1753 SDValue N0Op0 = N0.getOperand(0); 1754 APInt Mask = ~N1C->getAPIntValue(); 1755 Mask.trunc(N0Op0.getValueSizeInBits()); 1756 if (DAG.MaskedValueIsZero(N0Op0, Mask)) { 1757 SDValue Zext = DAG.getNode(ISD::ZERO_EXTEND, N0.getValueType(), 1758 N0Op0); 1759 1760 // Replace uses of the AND with uses of the Zero extend node. 1761 CombineTo(N, Zext); 1762 1763 // We actually want to replace all uses of the any_extend with the 1764 // zero_extend, to avoid duplicating things. This will later cause this 1765 // AND to be folded. 1766 CombineTo(N0.getNode(), Zext); 1767 return SDValue(N, 0); // Return N so it doesn't get rechecked! 1768 } 1769 } 1770 // fold (and (setcc x), (setcc y)) -> (setcc (and x, y)) 1771 if (isSetCCEquivalent(N0, LL, LR, CC0) && isSetCCEquivalent(N1, RL, RR, CC1)){ 1772 ISD::CondCode Op0 = cast<CondCodeSDNode>(CC0)->get(); 1773 ISD::CondCode Op1 = cast<CondCodeSDNode>(CC1)->get(); 1774 1775 if (LR == RR && isa<ConstantSDNode>(LR) && Op0 == Op1 && 1776 LL.getValueType().isInteger()) { 1777 // fold (X == 0) & (Y == 0) -> (X|Y == 0) 1778 if (cast<ConstantSDNode>(LR)->isNullValue() && Op1 == ISD::SETEQ) { 1779 SDValue ORNode = DAG.getNode(ISD::OR, LR.getValueType(), LL, RL); 1780 AddToWorkList(ORNode.getNode()); 1781 return DAG.getSetCC(VT, ORNode, LR, Op1); 1782 } 1783 // fold (X == -1) & (Y == -1) -> (X&Y == -1) 1784 if (cast<ConstantSDNode>(LR)->isAllOnesValue() && Op1 == ISD::SETEQ) { 1785 SDValue ANDNode = DAG.getNode(ISD::AND, LR.getValueType(), LL, RL); 1786 AddToWorkList(ANDNode.getNode()); 1787 return DAG.getSetCC(VT, ANDNode, LR, Op1); 1788 } 1789 // fold (X > -1) & (Y > -1) -> (X|Y > -1) 1790 if (cast<ConstantSDNode>(LR)->isAllOnesValue() && Op1 == ISD::SETGT) { 1791 SDValue ORNode = DAG.getNode(ISD::OR, LR.getValueType(), LL, RL); 1792 AddToWorkList(ORNode.getNode()); 1793 return DAG.getSetCC(VT, ORNode, LR, Op1); 1794 } 1795 } 1796 // canonicalize equivalent to ll == rl 1797 if (LL == RR && LR == RL) { 1798 Op1 = ISD::getSetCCSwappedOperands(Op1); 1799 std::swap(RL, RR); 1800 } 1801 if (LL == RL && LR == RR) { 1802 bool isInteger = LL.getValueType().isInteger(); 1803 ISD::CondCode Result = ISD::getSetCCAndOperation(Op0, Op1, isInteger); 1804 if (Result != ISD::SETCC_INVALID && 1805 (!LegalOperations || TLI.isCondCodeLegal(Result, LL.getValueType()))) 1806 return DAG.getSetCC(N0.getValueType(), LL, LR, Result); 1807 } 1808 } 1809 1810 // Simplify: and (op x...), (op y...) -> (op (and x, y)) 1811 if (N0.getOpcode() == N1.getOpcode()) { 1812 SDValue Tmp = SimplifyBinOpWithSameOpcodeHands(N); 1813 if (Tmp.getNode()) return Tmp; 1814 } 1815 1816 // fold (and (sign_extend_inreg x, i16 to i32), 1) -> (and x, 1) 1817 // fold (and (sra)) -> (and (srl)) when possible. 1818 if (!VT.isVector() && 1819 SimplifyDemandedBits(SDValue(N, 0))) 1820 return SDValue(N, 0); 1821 // fold (zext_inreg (extload x)) -> (zextload x) 1822 if (ISD::isEXTLoad(N0.getNode()) && ISD::isUNINDEXEDLoad(N0.getNode())) { 1823 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 1824 MVT EVT = LN0->getMemoryVT(); 1825 // If we zero all the possible extended bits, then we can turn this into 1826 // a zextload if we are running before legalize or the operation is legal. 1827 unsigned BitWidth = N1.getValueSizeInBits(); 1828 if (DAG.MaskedValueIsZero(N1, APInt::getHighBitsSet(BitWidth, 1829 BitWidth - EVT.getSizeInBits())) && 1830 ((!LegalOperations && !LN0->isVolatile()) || 1831 TLI.isLoadExtLegal(ISD::ZEXTLOAD, EVT))) { 1832 SDValue ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, LN0->getChain(), 1833 LN0->getBasePtr(), LN0->getSrcValue(), 1834 LN0->getSrcValueOffset(), EVT, 1835 LN0->isVolatile(), LN0->getAlignment()); 1836 AddToWorkList(N); 1837 CombineTo(N0.getNode(), ExtLoad, ExtLoad.getValue(1)); 1838 return SDValue(N, 0); // Return N so it doesn't get rechecked! 1839 } 1840 } 1841 // fold (zext_inreg (sextload x)) -> (zextload x) iff load has one use 1842 if (ISD::isSEXTLoad(N0.getNode()) && ISD::isUNINDEXEDLoad(N0.getNode()) && 1843 N0.hasOneUse()) { 1844 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 1845 MVT EVT = LN0->getMemoryVT(); 1846 // If we zero all the possible extended bits, then we can turn this into 1847 // a zextload if we are running before legalize or the operation is legal. 1848 unsigned BitWidth = N1.getValueSizeInBits(); 1849 if (DAG.MaskedValueIsZero(N1, APInt::getHighBitsSet(BitWidth, 1850 BitWidth - EVT.getSizeInBits())) && 1851 ((!LegalOperations && !LN0->isVolatile()) || 1852 TLI.isLoadExtLegal(ISD::ZEXTLOAD, EVT))) { 1853 SDValue ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, LN0->getChain(), 1854 LN0->getBasePtr(), LN0->getSrcValue(), 1855 LN0->getSrcValueOffset(), EVT, 1856 LN0->isVolatile(), LN0->getAlignment()); 1857 AddToWorkList(N); 1858 CombineTo(N0.getNode(), ExtLoad, ExtLoad.getValue(1)); 1859 return SDValue(N, 0); // Return N so it doesn't get rechecked! 1860 } 1861 } 1862 1863 // fold (and (load x), 255) -> (zextload x, i8) 1864 // fold (and (extload x, i16), 255) -> (zextload x, i8) 1865 if (N1C && N0.getOpcode() == ISD::LOAD) { 1866 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 1867 if (LN0->getExtensionType() != ISD::SEXTLOAD && 1868 LN0->isUnindexed() && N0.hasOneUse() && 1869 // Do not change the width of a volatile load. 1870 !LN0->isVolatile()) { 1871 MVT EVT = MVT::Other; 1872 uint32_t ActiveBits = N1C->getAPIntValue().getActiveBits(); 1873 if (ActiveBits > 0 && APIntOps::isMask(ActiveBits, N1C->getAPIntValue())) 1874 EVT = MVT::getIntegerVT(ActiveBits); 1875 1876 MVT LoadedVT = LN0->getMemoryVT(); 1877 // Do not generate loads of non-round integer types since these can 1878 // be expensive (and would be wrong if the type is not byte sized). 1879 if (EVT != MVT::Other && LoadedVT.bitsGT(EVT) && EVT.isRound() && 1880 (!LegalOperations || TLI.isLoadExtLegal(ISD::ZEXTLOAD, EVT))) { 1881 MVT PtrType = N0.getOperand(1).getValueType(); 1882 // For big endian targets, we need to add an offset to the pointer to 1883 // load the correct bytes. For little endian systems, we merely need to 1884 // read fewer bytes from the same pointer. 1885 unsigned LVTStoreBytes = LoadedVT.getStoreSizeInBits()/8; 1886 unsigned EVTStoreBytes = EVT.getStoreSizeInBits()/8; 1887 unsigned PtrOff = LVTStoreBytes - EVTStoreBytes; 1888 unsigned Alignment = LN0->getAlignment(); 1889 SDValue NewPtr = LN0->getBasePtr(); 1890 if (TLI.isBigEndian()) { 1891 NewPtr = DAG.getNode(ISD::ADD, PtrType, NewPtr, 1892 DAG.getConstant(PtrOff, PtrType)); 1893 Alignment = MinAlign(Alignment, PtrOff); 1894 } 1895 AddToWorkList(NewPtr.getNode()); 1896 SDValue Load = 1897 DAG.getExtLoad(ISD::ZEXTLOAD, VT, LN0->getChain(), NewPtr, 1898 LN0->getSrcValue(), LN0->getSrcValueOffset(), EVT, 1899 LN0->isVolatile(), Alignment); 1900 AddToWorkList(N); 1901 CombineTo(N0.getNode(), Load, Load.getValue(1)); 1902 return SDValue(N, 0); // Return N so it doesn't get rechecked! 1903 } 1904 } 1905 } 1906 1907 return SDValue(); 1908} 1909 1910SDValue DAGCombiner::visitOR(SDNode *N) { 1911 SDValue N0 = N->getOperand(0); 1912 SDValue N1 = N->getOperand(1); 1913 SDValue LL, LR, RL, RR, CC0, CC1; 1914 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 1915 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1916 MVT VT = N1.getValueType(); 1917 1918 // fold vector ops 1919 if (VT.isVector()) { 1920 SDValue FoldedVOp = SimplifyVBinOp(N); 1921 if (FoldedVOp.getNode()) return FoldedVOp; 1922 } 1923 1924 // fold (or x, undef) -> -1 1925 if (N0.getOpcode() == ISD::UNDEF || N1.getOpcode() == ISD::UNDEF) 1926 return DAG.getConstant(~0ULL, VT); 1927 // fold (or c1, c2) -> c1|c2 1928 if (N0C && N1C) 1929 return DAG.FoldConstantArithmetic(ISD::OR, VT, N0C, N1C); 1930 // canonicalize constant to RHS 1931 if (N0C && !N1C) 1932 return DAG.getNode(ISD::OR, VT, N1, N0); 1933 // fold (or x, 0) -> x 1934 if (N1C && N1C->isNullValue()) 1935 return N0; 1936 // fold (or x, -1) -> -1 1937 if (N1C && N1C->isAllOnesValue()) 1938 return N1; 1939 // fold (or x, c) -> c iff (x & ~c) == 0 1940 if (N1C && DAG.MaskedValueIsZero(N0, ~N1C->getAPIntValue())) 1941 return N1; 1942 // reassociate or 1943 SDValue ROR = ReassociateOps(ISD::OR, N0, N1); 1944 if (ROR.getNode() != 0) 1945 return ROR; 1946 // Canonicalize (or (and X, c1), c2) -> (and (or X, c2), c1|c2) 1947 if (N1C && N0.getOpcode() == ISD::AND && N0.getNode()->hasOneUse() && 1948 isa<ConstantSDNode>(N0.getOperand(1))) { 1949 ConstantSDNode *C1 = cast<ConstantSDNode>(N0.getOperand(1)); 1950 return DAG.getNode(ISD::AND, VT, DAG.getNode(ISD::OR, VT, N0.getOperand(0), 1951 N1), 1952 DAG.getConstant(N1C->getAPIntValue() | 1953 C1->getAPIntValue(), VT)); 1954 } 1955 // fold (or (setcc x), (setcc y)) -> (setcc (or x, y)) 1956 if (isSetCCEquivalent(N0, LL, LR, CC0) && isSetCCEquivalent(N1, RL, RR, CC1)){ 1957 ISD::CondCode Op0 = cast<CondCodeSDNode>(CC0)->get(); 1958 ISD::CondCode Op1 = cast<CondCodeSDNode>(CC1)->get(); 1959 1960 if (LR == RR && isa<ConstantSDNode>(LR) && Op0 == Op1 && 1961 LL.getValueType().isInteger()) { 1962 // fold (X != 0) | (Y != 0) -> (X|Y != 0) 1963 // fold (X < 0) | (Y < 0) -> (X|Y < 0) 1964 if (cast<ConstantSDNode>(LR)->isNullValue() && 1965 (Op1 == ISD::SETNE || Op1 == ISD::SETLT)) { 1966 SDValue ORNode = DAG.getNode(ISD::OR, LR.getValueType(), LL, RL); 1967 AddToWorkList(ORNode.getNode()); 1968 return DAG.getSetCC(VT, ORNode, LR, Op1); 1969 } 1970 // fold (X != -1) | (Y != -1) -> (X&Y != -1) 1971 // fold (X > -1) | (Y > -1) -> (X&Y > -1) 1972 if (cast<ConstantSDNode>(LR)->isAllOnesValue() && 1973 (Op1 == ISD::SETNE || Op1 == ISD::SETGT)) { 1974 SDValue ANDNode = DAG.getNode(ISD::AND, LR.getValueType(), LL, RL); 1975 AddToWorkList(ANDNode.getNode()); 1976 return DAG.getSetCC(VT, ANDNode, LR, Op1); 1977 } 1978 } 1979 // canonicalize equivalent to ll == rl 1980 if (LL == RR && LR == RL) { 1981 Op1 = ISD::getSetCCSwappedOperands(Op1); 1982 std::swap(RL, RR); 1983 } 1984 if (LL == RL && LR == RR) { 1985 bool isInteger = LL.getValueType().isInteger(); 1986 ISD::CondCode Result = ISD::getSetCCOrOperation(Op0, Op1, isInteger); 1987 if (Result != ISD::SETCC_INVALID && 1988 (!LegalOperations || TLI.isCondCodeLegal(Result, LL.getValueType()))) 1989 return DAG.getSetCC(N0.getValueType(), LL, LR, Result); 1990 } 1991 } 1992 1993 // Simplify: or (op x...), (op y...) -> (op (or x, y)) 1994 if (N0.getOpcode() == N1.getOpcode()) { 1995 SDValue Tmp = SimplifyBinOpWithSameOpcodeHands(N); 1996 if (Tmp.getNode()) return Tmp; 1997 } 1998 1999 // (X & C1) | (Y & C2) -> (X|Y) & C3 if possible. 2000 if (N0.getOpcode() == ISD::AND && 2001 N1.getOpcode() == ISD::AND && 2002 N0.getOperand(1).getOpcode() == ISD::Constant && 2003 N1.getOperand(1).getOpcode() == ISD::Constant && 2004 // Don't increase # computations. 2005 (N0.getNode()->hasOneUse() || N1.getNode()->hasOneUse())) { 2006 // We can only do this xform if we know that bits from X that are set in C2 2007 // but not in C1 are already zero. Likewise for Y. 2008 const APInt &LHSMask = 2009 cast<ConstantSDNode>(N0.getOperand(1))->getAPIntValue(); 2010 const APInt &RHSMask = 2011 cast<ConstantSDNode>(N1.getOperand(1))->getAPIntValue(); 2012 2013 if (DAG.MaskedValueIsZero(N0.getOperand(0), RHSMask&~LHSMask) && 2014 DAG.MaskedValueIsZero(N1.getOperand(0), LHSMask&~RHSMask)) { 2015 SDValue X =DAG.getNode(ISD::OR, VT, N0.getOperand(0), N1.getOperand(0)); 2016 return DAG.getNode(ISD::AND, VT, X, DAG.getConstant(LHSMask|RHSMask, VT)); 2017 } 2018 } 2019 2020 2021 // See if this is some rotate idiom. 2022 if (SDNode *Rot = MatchRotate(N0, N1)) 2023 return SDValue(Rot, 0); 2024 2025 return SDValue(); 2026} 2027 2028 2029/// MatchRotateHalf - Match "(X shl/srl V1) & V2" where V2 may not be present. 2030static bool MatchRotateHalf(SDValue Op, SDValue &Shift, SDValue &Mask) { 2031 if (Op.getOpcode() == ISD::AND) { 2032 if (isa<ConstantSDNode>(Op.getOperand(1))) { 2033 Mask = Op.getOperand(1); 2034 Op = Op.getOperand(0); 2035 } else { 2036 return false; 2037 } 2038 } 2039 2040 if (Op.getOpcode() == ISD::SRL || Op.getOpcode() == ISD::SHL) { 2041 Shift = Op; 2042 return true; 2043 } 2044 return false; 2045} 2046 2047 2048// MatchRotate - Handle an 'or' of two operands. If this is one of the many 2049// idioms for rotate, and if the target supports rotation instructions, generate 2050// a rot[lr]. 2051SDNode *DAGCombiner::MatchRotate(SDValue LHS, SDValue RHS) { 2052 // Must be a legal type. Expanded 'n promoted things won't work with rotates. 2053 MVT VT = LHS.getValueType(); 2054 if (!TLI.isTypeLegal(VT)) return 0; 2055 2056 // The target must have at least one rotate flavor. 2057 bool HasROTL = TLI.isOperationLegal(ISD::ROTL, VT); 2058 bool HasROTR = TLI.isOperationLegal(ISD::ROTR, VT); 2059 if (!HasROTL && !HasROTR) return 0; 2060 2061 // Match "(X shl/srl V1) & V2" where V2 may not be present. 2062 SDValue LHSShift; // The shift. 2063 SDValue LHSMask; // AND value if any. 2064 if (!MatchRotateHalf(LHS, LHSShift, LHSMask)) 2065 return 0; // Not part of a rotate. 2066 2067 SDValue RHSShift; // The shift. 2068 SDValue RHSMask; // AND value if any. 2069 if (!MatchRotateHalf(RHS, RHSShift, RHSMask)) 2070 return 0; // Not part of a rotate. 2071 2072 if (LHSShift.getOperand(0) != RHSShift.getOperand(0)) 2073 return 0; // Not shifting the same value. 2074 2075 if (LHSShift.getOpcode() == RHSShift.getOpcode()) 2076 return 0; // Shifts must disagree. 2077 2078 // Canonicalize shl to left side in a shl/srl pair. 2079 if (RHSShift.getOpcode() == ISD::SHL) { 2080 std::swap(LHS, RHS); 2081 std::swap(LHSShift, RHSShift); 2082 std::swap(LHSMask , RHSMask ); 2083 } 2084 2085 unsigned OpSizeInBits = VT.getSizeInBits(); 2086 SDValue LHSShiftArg = LHSShift.getOperand(0); 2087 SDValue LHSShiftAmt = LHSShift.getOperand(1); 2088 SDValue RHSShiftAmt = RHSShift.getOperand(1); 2089 2090 // fold (or (shl x, C1), (srl x, C2)) -> (rotl x, C1) 2091 // fold (or (shl x, C1), (srl x, C2)) -> (rotr x, C2) 2092 if (LHSShiftAmt.getOpcode() == ISD::Constant && 2093 RHSShiftAmt.getOpcode() == ISD::Constant) { 2094 uint64_t LShVal = cast<ConstantSDNode>(LHSShiftAmt)->getZExtValue(); 2095 uint64_t RShVal = cast<ConstantSDNode>(RHSShiftAmt)->getZExtValue(); 2096 if ((LShVal + RShVal) != OpSizeInBits) 2097 return 0; 2098 2099 SDValue Rot; 2100 if (HasROTL) 2101 Rot = DAG.getNode(ISD::ROTL, VT, LHSShiftArg, LHSShiftAmt); 2102 else 2103 Rot = DAG.getNode(ISD::ROTR, VT, LHSShiftArg, RHSShiftAmt); 2104 2105 // If there is an AND of either shifted operand, apply it to the result. 2106 if (LHSMask.getNode() || RHSMask.getNode()) { 2107 APInt Mask = APInt::getAllOnesValue(OpSizeInBits); 2108 2109 if (LHSMask.getNode()) { 2110 APInt RHSBits = APInt::getLowBitsSet(OpSizeInBits, LShVal); 2111 Mask &= cast<ConstantSDNode>(LHSMask)->getAPIntValue() | RHSBits; 2112 } 2113 if (RHSMask.getNode()) { 2114 APInt LHSBits = APInt::getHighBitsSet(OpSizeInBits, RShVal); 2115 Mask &= cast<ConstantSDNode>(RHSMask)->getAPIntValue() | LHSBits; 2116 } 2117 2118 Rot = DAG.getNode(ISD::AND, VT, Rot, DAG.getConstant(Mask, VT)); 2119 } 2120 2121 return Rot.getNode(); 2122 } 2123 2124 // If there is a mask here, and we have a variable shift, we can't be sure 2125 // that we're masking out the right stuff. 2126 if (LHSMask.getNode() || RHSMask.getNode()) 2127 return 0; 2128 2129 // fold (or (shl x, y), (srl x, (sub 32, y))) -> (rotl x, y) 2130 // fold (or (shl x, y), (srl x, (sub 32, y))) -> (rotr x, (sub 32, y)) 2131 if (RHSShiftAmt.getOpcode() == ISD::SUB && 2132 LHSShiftAmt == RHSShiftAmt.getOperand(1)) { 2133 if (ConstantSDNode *SUBC = 2134 dyn_cast<ConstantSDNode>(RHSShiftAmt.getOperand(0))) { 2135 if (SUBC->getAPIntValue() == OpSizeInBits) { 2136 if (HasROTL) 2137 return DAG.getNode(ISD::ROTL, VT, LHSShiftArg, LHSShiftAmt).getNode(); 2138 else 2139 return DAG.getNode(ISD::ROTR, VT, LHSShiftArg, RHSShiftAmt).getNode(); 2140 } 2141 } 2142 } 2143 2144 // fold (or (shl x, (sub 32, y)), (srl x, r)) -> (rotr x, y) 2145 // fold (or (shl x, (sub 32, y)), (srl x, r)) -> (rotl x, (sub 32, y)) 2146 if (LHSShiftAmt.getOpcode() == ISD::SUB && 2147 RHSShiftAmt == LHSShiftAmt.getOperand(1)) { 2148 if (ConstantSDNode *SUBC = 2149 dyn_cast<ConstantSDNode>(LHSShiftAmt.getOperand(0))) { 2150 if (SUBC->getAPIntValue() == OpSizeInBits) { 2151 if (HasROTR) 2152 return DAG.getNode(ISD::ROTR, VT, LHSShiftArg, RHSShiftAmt).getNode(); 2153 else 2154 return DAG.getNode(ISD::ROTL, VT, LHSShiftArg, LHSShiftAmt).getNode(); 2155 } 2156 } 2157 } 2158 2159 // Look for sign/zext/any-extended or truncate cases: 2160 if ((LHSShiftAmt.getOpcode() == ISD::SIGN_EXTEND 2161 || LHSShiftAmt.getOpcode() == ISD::ZERO_EXTEND 2162 || LHSShiftAmt.getOpcode() == ISD::ANY_EXTEND 2163 || LHSShiftAmt.getOpcode() == ISD::TRUNCATE) && 2164 (RHSShiftAmt.getOpcode() == ISD::SIGN_EXTEND 2165 || RHSShiftAmt.getOpcode() == ISD::ZERO_EXTEND 2166 || RHSShiftAmt.getOpcode() == ISD::ANY_EXTEND 2167 || RHSShiftAmt.getOpcode() == ISD::TRUNCATE)) { 2168 SDValue LExtOp0 = LHSShiftAmt.getOperand(0); 2169 SDValue RExtOp0 = RHSShiftAmt.getOperand(0); 2170 if (RExtOp0.getOpcode() == ISD::SUB && 2171 RExtOp0.getOperand(1) == LExtOp0) { 2172 // fold (or (shl x, (*ext y)), (srl x, (*ext (sub 32, y)))) -> 2173 // (rotl x, y) 2174 // fold (or (shl x, (*ext y)), (srl x, (*ext (sub 32, y)))) -> 2175 // (rotr x, (sub 32, y)) 2176 if (ConstantSDNode *SUBC = 2177 dyn_cast<ConstantSDNode>(RExtOp0.getOperand(0))) { 2178 if (SUBC->getAPIntValue() == OpSizeInBits) { 2179 return DAG.getNode(HasROTL ? ISD::ROTL : ISD::ROTR, VT, LHSShiftArg, 2180 HasROTL ? LHSShiftAmt : RHSShiftAmt).getNode(); 2181 } 2182 } 2183 } else if (LExtOp0.getOpcode() == ISD::SUB && 2184 RExtOp0 == LExtOp0.getOperand(1)) { 2185 // fold (or (shl x, (*ext (sub 32, y))), (srl x, (*ext y))) -> 2186 // (rotr x, y) 2187 // fold (or (shl x, (*ext (sub 32, y))), (srl x, (*ext y))) -> 2188 // (rotl x, (sub 32, y)) 2189 if (ConstantSDNode *SUBC = 2190 dyn_cast<ConstantSDNode>(LExtOp0.getOperand(0))) { 2191 if (SUBC->getAPIntValue() == OpSizeInBits) { 2192 return DAG.getNode(HasROTR ? ISD::ROTR : ISD::ROTL, VT, LHSShiftArg, 2193 HasROTR ? RHSShiftAmt : LHSShiftAmt).getNode(); 2194 } 2195 } 2196 } 2197 } 2198 2199 return 0; 2200} 2201 2202 2203SDValue DAGCombiner::visitXOR(SDNode *N) { 2204 SDValue N0 = N->getOperand(0); 2205 SDValue N1 = N->getOperand(1); 2206 SDValue LHS, RHS, CC; 2207 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 2208 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 2209 MVT VT = N0.getValueType(); 2210 2211 // fold vector ops 2212 if (VT.isVector()) { 2213 SDValue FoldedVOp = SimplifyVBinOp(N); 2214 if (FoldedVOp.getNode()) return FoldedVOp; 2215 } 2216 2217 // fold (xor undef, undef) -> 0. This is a common idiom (misuse). 2218 if (N0.getOpcode() == ISD::UNDEF && N1.getOpcode() == ISD::UNDEF) 2219 return DAG.getConstant(0, VT); 2220 // fold (xor x, undef) -> undef 2221 if (N0.getOpcode() == ISD::UNDEF) 2222 return N0; 2223 if (N1.getOpcode() == ISD::UNDEF) 2224 return N1; 2225 // fold (xor c1, c2) -> c1^c2 2226 if (N0C && N1C) 2227 return DAG.FoldConstantArithmetic(ISD::XOR, VT, N0C, N1C); 2228 // canonicalize constant to RHS 2229 if (N0C && !N1C) 2230 return DAG.getNode(ISD::XOR, VT, N1, N0); 2231 // fold (xor x, 0) -> x 2232 if (N1C && N1C->isNullValue()) 2233 return N0; 2234 // reassociate xor 2235 SDValue RXOR = ReassociateOps(ISD::XOR, N0, N1); 2236 if (RXOR.getNode() != 0) 2237 return RXOR; 2238 2239 // fold !(x cc y) -> (x !cc y) 2240 if (N1C && N1C->getAPIntValue() == 1 && isSetCCEquivalent(N0, LHS, RHS, CC)) { 2241 bool isInt = LHS.getValueType().isInteger(); 2242 ISD::CondCode NotCC = ISD::getSetCCInverse(cast<CondCodeSDNode>(CC)->get(), 2243 isInt); 2244 2245 if (!LegalOperations || TLI.isCondCodeLegal(NotCC, LHS.getValueType())) { 2246 switch (N0.getOpcode()) { 2247 default: 2248 assert(0 && "Unhandled SetCC Equivalent!"); 2249 abort(); 2250 case ISD::SETCC: 2251 return DAG.getSetCC(VT, LHS, RHS, NotCC); 2252 case ISD::SELECT_CC: 2253 return DAG.getSelectCC(LHS, RHS, N0.getOperand(2), 2254 N0.getOperand(3), NotCC); 2255 } 2256 } 2257 } 2258 2259 // fold (not (zext (setcc x, y))) -> (zext (not (setcc x, y))) 2260 if (N1C && N1C->getAPIntValue() == 1 && N0.getOpcode() == ISD::ZERO_EXTEND && 2261 N0.getNode()->hasOneUse() && 2262 isSetCCEquivalent(N0.getOperand(0), LHS, RHS, CC)){ 2263 SDValue V = N0.getOperand(0); 2264 V = DAG.getNode(ISD::XOR, V.getValueType(), V, 2265 DAG.getConstant(1, V.getValueType())); 2266 AddToWorkList(V.getNode()); 2267 return DAG.getNode(ISD::ZERO_EXTEND, VT, V); 2268 } 2269 2270 // fold !(x or y) -> (!x and !y) iff x or y are setcc 2271 if (N1C && N1C->getAPIntValue() == 1 && VT == MVT::i1 && 2272 (N0.getOpcode() == ISD::OR || N0.getOpcode() == ISD::AND)) { 2273 SDValue LHS = N0.getOperand(0), RHS = N0.getOperand(1); 2274 if (isOneUseSetCC(RHS) || isOneUseSetCC(LHS)) { 2275 unsigned NewOpcode = N0.getOpcode() == ISD::AND ? ISD::OR : ISD::AND; 2276 LHS = DAG.getNode(ISD::XOR, VT, LHS, N1); // RHS = ~LHS 2277 RHS = DAG.getNode(ISD::XOR, VT, RHS, N1); // RHS = ~RHS 2278 AddToWorkList(LHS.getNode()); AddToWorkList(RHS.getNode()); 2279 return DAG.getNode(NewOpcode, VT, LHS, RHS); 2280 } 2281 } 2282 // fold !(x or y) -> (!x and !y) iff x or y are constants 2283 if (N1C && N1C->isAllOnesValue() && 2284 (N0.getOpcode() == ISD::OR || N0.getOpcode() == ISD::AND)) { 2285 SDValue LHS = N0.getOperand(0), RHS = N0.getOperand(1); 2286 if (isa<ConstantSDNode>(RHS) || isa<ConstantSDNode>(LHS)) { 2287 unsigned NewOpcode = N0.getOpcode() == ISD::AND ? ISD::OR : ISD::AND; 2288 LHS = DAG.getNode(ISD::XOR, VT, LHS, N1); // RHS = ~LHS 2289 RHS = DAG.getNode(ISD::XOR, VT, RHS, N1); // RHS = ~RHS 2290 AddToWorkList(LHS.getNode()); AddToWorkList(RHS.getNode()); 2291 return DAG.getNode(NewOpcode, VT, LHS, RHS); 2292 } 2293 } 2294 // fold (xor (xor x, c1), c2) -> (xor x, c1^c2) 2295 if (N1C && N0.getOpcode() == ISD::XOR) { 2296 ConstantSDNode *N00C = dyn_cast<ConstantSDNode>(N0.getOperand(0)); 2297 ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N0.getOperand(1)); 2298 if (N00C) 2299 return DAG.getNode(ISD::XOR, VT, N0.getOperand(1), 2300 DAG.getConstant(N1C->getAPIntValue()^ 2301 N00C->getAPIntValue(), VT)); 2302 if (N01C) 2303 return DAG.getNode(ISD::XOR, VT, N0.getOperand(0), 2304 DAG.getConstant(N1C->getAPIntValue()^ 2305 N01C->getAPIntValue(), VT)); 2306 } 2307 // fold (xor x, x) -> 0 2308 if (N0 == N1) { 2309 if (!VT.isVector()) { 2310 return DAG.getConstant(0, VT); 2311 } else if (!LegalOperations || TLI.isOperationLegal(ISD::BUILD_VECTOR, VT)){ 2312 // Produce a vector of zeros. 2313 SDValue El = DAG.getConstant(0, VT.getVectorElementType()); 2314 std::vector<SDValue> Ops(VT.getVectorNumElements(), El); 2315 return DAG.getNode(ISD::BUILD_VECTOR, VT, &Ops[0], Ops.size()); 2316 } 2317 } 2318 2319 // Simplify: xor (op x...), (op y...) -> (op (xor x, y)) 2320 if (N0.getOpcode() == N1.getOpcode()) { 2321 SDValue Tmp = SimplifyBinOpWithSameOpcodeHands(N); 2322 if (Tmp.getNode()) return Tmp; 2323 } 2324 2325 // Simplify the expression using non-local knowledge. 2326 if (!VT.isVector() && 2327 SimplifyDemandedBits(SDValue(N, 0))) 2328 return SDValue(N, 0); 2329 2330 return SDValue(); 2331} 2332 2333/// visitShiftByConstant - Handle transforms common to the three shifts, when 2334/// the shift amount is a constant. 2335SDValue DAGCombiner::visitShiftByConstant(SDNode *N, unsigned Amt) { 2336 SDNode *LHS = N->getOperand(0).getNode(); 2337 if (!LHS->hasOneUse()) return SDValue(); 2338 2339 // We want to pull some binops through shifts, so that we have (and (shift)) 2340 // instead of (shift (and)), likewise for add, or, xor, etc. This sort of 2341 // thing happens with address calculations, so it's important to canonicalize 2342 // it. 2343 bool HighBitSet = false; // Can we transform this if the high bit is set? 2344 2345 switch (LHS->getOpcode()) { 2346 default: return SDValue(); 2347 case ISD::OR: 2348 case ISD::XOR: 2349 HighBitSet = false; // We can only transform sra if the high bit is clear. 2350 break; 2351 case ISD::AND: 2352 HighBitSet = true; // We can only transform sra if the high bit is set. 2353 break; 2354 case ISD::ADD: 2355 if (N->getOpcode() != ISD::SHL) 2356 return SDValue(); // only shl(add) not sr[al](add). 2357 HighBitSet = false; // We can only transform sra if the high bit is clear. 2358 break; 2359 } 2360 2361 // We require the RHS of the binop to be a constant as well. 2362 ConstantSDNode *BinOpCst = dyn_cast<ConstantSDNode>(LHS->getOperand(1)); 2363 if (!BinOpCst) return SDValue(); 2364 2365 2366 // FIXME: disable this for unless the input to the binop is a shift by a 2367 // constant. If it is not a shift, it pessimizes some common cases like: 2368 // 2369 //void foo(int *X, int i) { X[i & 1235] = 1; } 2370 //int bar(int *X, int i) { return X[i & 255]; } 2371 SDNode *BinOpLHSVal = LHS->getOperand(0).getNode(); 2372 if ((BinOpLHSVal->getOpcode() != ISD::SHL && 2373 BinOpLHSVal->getOpcode() != ISD::SRA && 2374 BinOpLHSVal->getOpcode() != ISD::SRL) || 2375 !isa<ConstantSDNode>(BinOpLHSVal->getOperand(1))) 2376 return SDValue(); 2377 2378 MVT VT = N->getValueType(0); 2379 2380 // If this is a signed shift right, and the high bit is modified 2381 // by the logical operation, do not perform the transformation. 2382 // The highBitSet boolean indicates the value of the high bit of 2383 // the constant which would cause it to be modified for this 2384 // operation. 2385 if (N->getOpcode() == ISD::SRA) { 2386 bool BinOpRHSSignSet = BinOpCst->getAPIntValue().isNegative(); 2387 if (BinOpRHSSignSet != HighBitSet) 2388 return SDValue(); 2389 } 2390 2391 // Fold the constants, shifting the binop RHS by the shift amount. 2392 SDValue NewRHS = DAG.getNode(N->getOpcode(), N->getValueType(0), 2393 LHS->getOperand(1), N->getOperand(1)); 2394 2395 // Create the new shift. 2396 SDValue NewShift = DAG.getNode(N->getOpcode(), VT, LHS->getOperand(0), 2397 N->getOperand(1)); 2398 2399 // Create the new binop. 2400 return DAG.getNode(LHS->getOpcode(), VT, NewShift, NewRHS); 2401} 2402 2403 2404SDValue DAGCombiner::visitSHL(SDNode *N) { 2405 SDValue N0 = N->getOperand(0); 2406 SDValue N1 = N->getOperand(1); 2407 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 2408 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 2409 MVT VT = N0.getValueType(); 2410 unsigned OpSizeInBits = VT.getSizeInBits(); 2411 2412 // fold (shl c1, c2) -> c1<<c2 2413 if (N0C && N1C) 2414 return DAG.FoldConstantArithmetic(ISD::SHL, VT, N0C, N1C); 2415 // fold (shl 0, x) -> 0 2416 if (N0C && N0C->isNullValue()) 2417 return N0; 2418 // fold (shl x, c >= size(x)) -> undef 2419 if (N1C && N1C->getZExtValue() >= OpSizeInBits) 2420 return DAG.getNode(ISD::UNDEF, VT); 2421 // fold (shl x, 0) -> x 2422 if (N1C && N1C->isNullValue()) 2423 return N0; 2424 // if (shl x, c) is known to be zero, return 0 2425 if (DAG.MaskedValueIsZero(SDValue(N, 0), 2426 APInt::getAllOnesValue(VT.getSizeInBits()))) 2427 return DAG.getConstant(0, VT); 2428 // fold (shl x, (trunc (and y, c))) -> (shl x, (and (trunc y), c)) 2429 // iff (trunc c) == c 2430 if (N1.getOpcode() == ISD::TRUNCATE && 2431 N1.getOperand(0).getOpcode() == ISD::AND && 2432 N1.hasOneUse() && N1.getOperand(0).hasOneUse()) { 2433 SDValue N101 = N1.getOperand(0).getOperand(1); 2434 if (ConstantSDNode *N101C = dyn_cast<ConstantSDNode>(N101)) { 2435 MVT TruncVT = N1.getValueType(); 2436 SDValue N100 = N1.getOperand(0).getOperand(0); 2437 return DAG.getNode(ISD::SHL, VT, N0, 2438 DAG.getNode(ISD::AND, TruncVT, 2439 DAG.getNode(ISD::TRUNCATE, TruncVT, N100), 2440 DAG.getConstant(N101C->getZExtValue(), 2441 TruncVT))); 2442 } 2443 } 2444 2445 if (N1C && SimplifyDemandedBits(SDValue(N, 0))) 2446 return SDValue(N, 0); 2447 // fold (shl (shl x, c1), c2) -> 0 or (shl x, c1+c2) 2448 if (N1C && N0.getOpcode() == ISD::SHL && 2449 N0.getOperand(1).getOpcode() == ISD::Constant) { 2450 uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getZExtValue(); 2451 uint64_t c2 = N1C->getZExtValue(); 2452 if (c1 + c2 > OpSizeInBits) 2453 return DAG.getConstant(0, VT); 2454 return DAG.getNode(ISD::SHL, VT, N0.getOperand(0), 2455 DAG.getConstant(c1 + c2, N1.getValueType())); 2456 } 2457 // fold (shl (srl x, c1), c2) -> (shl (and x, -1 << c1), c2-c1) or 2458 // (srl (and x, -1 << c1), c1-c2) 2459 if (N1C && N0.getOpcode() == ISD::SRL && 2460 N0.getOperand(1).getOpcode() == ISD::Constant) { 2461 uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getZExtValue(); 2462 uint64_t c2 = N1C->getZExtValue(); 2463 SDValue Mask = DAG.getNode(ISD::AND, VT, N0.getOperand(0), 2464 DAG.getConstant(~0ULL << c1, VT)); 2465 if (c2 > c1) 2466 return DAG.getNode(ISD::SHL, VT, Mask, 2467 DAG.getConstant(c2-c1, N1.getValueType())); 2468 else 2469 return DAG.getNode(ISD::SRL, VT, Mask, 2470 DAG.getConstant(c1-c2, N1.getValueType())); 2471 } 2472 // fold (shl (sra x, c1), c1) -> (and x, -1 << c1) 2473 if (N1C && N0.getOpcode() == ISD::SRA && N1 == N0.getOperand(1)) 2474 return DAG.getNode(ISD::AND, VT, N0.getOperand(0), 2475 DAG.getConstant(~0ULL << N1C->getZExtValue(), VT)); 2476 2477 return N1C ? visitShiftByConstant(N, N1C->getZExtValue()) : SDValue(); 2478} 2479 2480SDValue DAGCombiner::visitSRA(SDNode *N) { 2481 SDValue N0 = N->getOperand(0); 2482 SDValue N1 = N->getOperand(1); 2483 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 2484 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 2485 MVT VT = N0.getValueType(); 2486 2487 // fold (sra c1, c2) -> c1>>c2 2488 if (N0C && N1C) 2489 return DAG.FoldConstantArithmetic(ISD::SRA, VT, N0C, N1C); 2490 // fold (sra 0, x) -> 0 2491 if (N0C && N0C->isNullValue()) 2492 return N0; 2493 // fold (sra -1, x) -> -1 2494 if (N0C && N0C->isAllOnesValue()) 2495 return N0; 2496 // fold (sra x, c >= size(x)) -> undef 2497 if (N1C && N1C->getZExtValue() >= VT.getSizeInBits()) 2498 return DAG.getNode(ISD::UNDEF, VT); 2499 // fold (sra x, 0) -> x 2500 if (N1C && N1C->isNullValue()) 2501 return N0; 2502 // fold (sra (shl x, c1), c1) -> sext_inreg for some c1 and target supports 2503 // sext_inreg. 2504 if (N1C && N0.getOpcode() == ISD::SHL && N1 == N0.getOperand(1)) { 2505 unsigned LowBits = VT.getSizeInBits() - (unsigned)N1C->getZExtValue(); 2506 MVT EVT = MVT::getIntegerVT(LowBits); 2507 if ((!LegalOperations || TLI.isOperationLegal(ISD::SIGN_EXTEND_INREG, EVT))) 2508 return DAG.getNode(ISD::SIGN_EXTEND_INREG, VT, N0.getOperand(0), 2509 DAG.getValueType(EVT)); 2510 } 2511 2512 // fold (sra (sra x, c1), c2) -> (sra x, c1+c2) 2513 if (N1C && N0.getOpcode() == ISD::SRA) { 2514 if (ConstantSDNode *C1 = dyn_cast<ConstantSDNode>(N0.getOperand(1))) { 2515 unsigned Sum = N1C->getZExtValue() + C1->getZExtValue(); 2516 if (Sum >= VT.getSizeInBits()) Sum = VT.getSizeInBits()-1; 2517 return DAG.getNode(ISD::SRA, VT, N0.getOperand(0), 2518 DAG.getConstant(Sum, N1C->getValueType(0))); 2519 } 2520 } 2521 2522 // fold sra (shl X, m), result_size - n 2523 // -> (sign_extend (trunc (shl X, result_size - n - m))) for 2524 // result_size - n != m. 2525 // If truncate is free for the target sext(shl) is likely to result in better 2526 // code. 2527 if (N0.getOpcode() == ISD::SHL) { 2528 // Get the two constanst of the shifts, CN0 = m, CN = n. 2529 const ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N0.getOperand(1)); 2530 if (N01C && N1C) { 2531 // Determine what the truncate's result bitsize and type would be. 2532 unsigned VTValSize = VT.getSizeInBits(); 2533 MVT TruncVT = 2534 MVT::getIntegerVT(VTValSize - N1C->getZExtValue()); 2535 // Determine the residual right-shift amount. 2536 unsigned ShiftAmt = N1C->getZExtValue() - N01C->getZExtValue(); 2537 2538 // If the shift is not a no-op (in which case this should be just a sign 2539 // extend already), the truncated to type is legal, sign_extend is legal 2540 // on that type, and the the truncate to that type is both legal and free, 2541 // perform the transform. 2542 if (ShiftAmt && 2543 TLI.isOperationLegal(ISD::SIGN_EXTEND, TruncVT) && 2544 TLI.isOperationLegal(ISD::TRUNCATE, VT) && 2545 TLI.isTruncateFree(VT, TruncVT)) { 2546 2547 SDValue Amt = DAG.getConstant(ShiftAmt, TLI.getShiftAmountTy()); 2548 SDValue Shift = DAG.getNode(ISD::SRL, VT, N0.getOperand(0), Amt); 2549 SDValue Trunc = DAG.getNode(ISD::TRUNCATE, TruncVT, Shift); 2550 return DAG.getNode(ISD::SIGN_EXTEND, N->getValueType(0), Trunc); 2551 } 2552 } 2553 } 2554 2555 // fold (sra x, (trunc (and y, c))) -> (sra x, (and (trunc y), c)) 2556 // iff (trunc c) == c 2557 if (N1.getOpcode() == ISD::TRUNCATE && 2558 N1.getOperand(0).getOpcode() == ISD::AND && 2559 N1.hasOneUse() && N1.getOperand(0).hasOneUse()) { 2560 SDValue N101 = N1.getOperand(0).getOperand(1); 2561 if (ConstantSDNode *N101C = dyn_cast<ConstantSDNode>(N101)) { 2562 MVT TruncVT = N1.getValueType(); 2563 SDValue N100 = N1.getOperand(0).getOperand(0); 2564 return DAG.getNode(ISD::SRA, VT, N0, 2565 DAG.getNode(ISD::AND, TruncVT, 2566 DAG.getNode(ISD::TRUNCATE, TruncVT, N100), 2567 DAG.getConstant(N101C->getZExtValue(), 2568 TruncVT))); 2569 } 2570 } 2571 2572 // Simplify, based on bits shifted out of the LHS. 2573 if (N1C && SimplifyDemandedBits(SDValue(N, 0))) 2574 return SDValue(N, 0); 2575 2576 2577 // If the sign bit is known to be zero, switch this to a SRL. 2578 if (DAG.SignBitIsZero(N0)) 2579 return DAG.getNode(ISD::SRL, VT, N0, N1); 2580 2581 return N1C ? visitShiftByConstant(N, N1C->getZExtValue()) : SDValue(); 2582} 2583 2584SDValue DAGCombiner::visitSRL(SDNode *N) { 2585 SDValue N0 = N->getOperand(0); 2586 SDValue N1 = N->getOperand(1); 2587 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 2588 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 2589 MVT VT = N0.getValueType(); 2590 unsigned OpSizeInBits = VT.getSizeInBits(); 2591 2592 // fold (srl c1, c2) -> c1 >>u c2 2593 if (N0C && N1C) 2594 return DAG.FoldConstantArithmetic(ISD::SRL, VT, N0C, N1C); 2595 // fold (srl 0, x) -> 0 2596 if (N0C && N0C->isNullValue()) 2597 return N0; 2598 // fold (srl x, c >= size(x)) -> undef 2599 if (N1C && N1C->getZExtValue() >= OpSizeInBits) 2600 return DAG.getNode(ISD::UNDEF, VT); 2601 // fold (srl x, 0) -> x 2602 if (N1C && N1C->isNullValue()) 2603 return N0; 2604 // if (srl x, c) is known to be zero, return 0 2605 if (N1C && DAG.MaskedValueIsZero(SDValue(N, 0), 2606 APInt::getAllOnesValue(OpSizeInBits))) 2607 return DAG.getConstant(0, VT); 2608 2609 // fold (srl (srl x, c1), c2) -> 0 or (srl x, c1+c2) 2610 if (N1C && N0.getOpcode() == ISD::SRL && 2611 N0.getOperand(1).getOpcode() == ISD::Constant) { 2612 uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getZExtValue(); 2613 uint64_t c2 = N1C->getZExtValue(); 2614 if (c1 + c2 > OpSizeInBits) 2615 return DAG.getConstant(0, VT); 2616 return DAG.getNode(ISD::SRL, VT, N0.getOperand(0), 2617 DAG.getConstant(c1 + c2, N1.getValueType())); 2618 } 2619 2620 // fold (srl (anyextend x), c) -> (anyextend (srl x, c)) 2621 if (N1C && N0.getOpcode() == ISD::ANY_EXTEND) { 2622 // Shifting in all undef bits? 2623 MVT SmallVT = N0.getOperand(0).getValueType(); 2624 if (N1C->getZExtValue() >= SmallVT.getSizeInBits()) 2625 return DAG.getNode(ISD::UNDEF, VT); 2626 2627 SDValue SmallShift = DAG.getNode(ISD::SRL, SmallVT, N0.getOperand(0), N1); 2628 AddToWorkList(SmallShift.getNode()); 2629 return DAG.getNode(ISD::ANY_EXTEND, VT, SmallShift); 2630 } 2631 2632 // fold (srl (sra X, Y), 31) -> (srl X, 31). This srl only looks at the sign 2633 // bit, which is unmodified by sra. 2634 if (N1C && N1C->getZExtValue()+1 == VT.getSizeInBits()) { 2635 if (N0.getOpcode() == ISD::SRA) 2636 return DAG.getNode(ISD::SRL, VT, N0.getOperand(0), N1); 2637 } 2638 2639 // fold (srl (ctlz x), "5") -> x iff x has one bit set (the low bit). 2640 if (N1C && N0.getOpcode() == ISD::CTLZ && 2641 N1C->getAPIntValue() == Log2_32(VT.getSizeInBits())) { 2642 APInt KnownZero, KnownOne; 2643 APInt Mask = APInt::getAllOnesValue(VT.getSizeInBits()); 2644 DAG.ComputeMaskedBits(N0.getOperand(0), Mask, KnownZero, KnownOne); 2645 2646 // If any of the input bits are KnownOne, then the input couldn't be all 2647 // zeros, thus the result of the srl will always be zero. 2648 if (KnownOne.getBoolValue()) return DAG.getConstant(0, VT); 2649 2650 // If all of the bits input the to ctlz node are known to be zero, then 2651 // the result of the ctlz is "32" and the result of the shift is one. 2652 APInt UnknownBits = ~KnownZero & Mask; 2653 if (UnknownBits == 0) return DAG.getConstant(1, VT); 2654 2655 // Otherwise, check to see if there is exactly one bit input to the ctlz. 2656 if ((UnknownBits & (UnknownBits-1)) == 0) { 2657 // Okay, we know that only that the single bit specified by UnknownBits 2658 // could be set on input to the CTLZ node. If this bit is set, the SRL 2659 // will return 0, if it is clear, it returns 1. Change the CTLZ/SRL pair 2660 // to an SRL,XOR pair, which is likely to simplify more. 2661 unsigned ShAmt = UnknownBits.countTrailingZeros(); 2662 SDValue Op = N0.getOperand(0); 2663 if (ShAmt) { 2664 Op = DAG.getNode(ISD::SRL, VT, Op, 2665 DAG.getConstant(ShAmt, TLI.getShiftAmountTy())); 2666 AddToWorkList(Op.getNode()); 2667 } 2668 return DAG.getNode(ISD::XOR, VT, Op, DAG.getConstant(1, VT)); 2669 } 2670 } 2671 2672 // fold (srl x, (trunc (and y, c))) -> (srl x, (and (trunc y), c)) 2673 // iff (trunc c) == c 2674 if (N1.getOpcode() == ISD::TRUNCATE && 2675 N1.getOperand(0).getOpcode() == ISD::AND && 2676 N1.hasOneUse() && N1.getOperand(0).hasOneUse()) { 2677 SDValue N101 = N1.getOperand(0).getOperand(1); 2678 if (ConstantSDNode *N101C = dyn_cast<ConstantSDNode>(N101)) { 2679 MVT TruncVT = N1.getValueType(); 2680 SDValue N100 = N1.getOperand(0).getOperand(0); 2681 return DAG.getNode(ISD::SRL, VT, N0, 2682 DAG.getNode(ISD::AND, TruncVT, 2683 DAG.getNode(ISD::TRUNCATE, TruncVT, N100), 2684 DAG.getConstant(N101C->getZExtValue(), 2685 TruncVT))); 2686 } 2687 } 2688 2689 // fold operands of srl based on knowledge that the low bits are not 2690 // demanded. 2691 if (N1C && SimplifyDemandedBits(SDValue(N, 0))) 2692 return SDValue(N, 0); 2693 2694 return N1C ? visitShiftByConstant(N, N1C->getZExtValue()) : SDValue(); 2695} 2696 2697SDValue DAGCombiner::visitCTLZ(SDNode *N) { 2698 SDValue N0 = N->getOperand(0); 2699 MVT VT = N->getValueType(0); 2700 2701 // fold (ctlz c1) -> c2 2702 if (isa<ConstantSDNode>(N0)) 2703 return DAG.getNode(ISD::CTLZ, VT, N0); 2704 return SDValue(); 2705} 2706 2707SDValue DAGCombiner::visitCTTZ(SDNode *N) { 2708 SDValue N0 = N->getOperand(0); 2709 MVT VT = N->getValueType(0); 2710 2711 // fold (cttz c1) -> c2 2712 if (isa<ConstantSDNode>(N0)) 2713 return DAG.getNode(ISD::CTTZ, VT, N0); 2714 return SDValue(); 2715} 2716 2717SDValue DAGCombiner::visitCTPOP(SDNode *N) { 2718 SDValue N0 = N->getOperand(0); 2719 MVT VT = N->getValueType(0); 2720 2721 // fold (ctpop c1) -> c2 2722 if (isa<ConstantSDNode>(N0)) 2723 return DAG.getNode(ISD::CTPOP, VT, N0); 2724 return SDValue(); 2725} 2726 2727SDValue DAGCombiner::visitSELECT(SDNode *N) { 2728 SDValue N0 = N->getOperand(0); 2729 SDValue N1 = N->getOperand(1); 2730 SDValue N2 = N->getOperand(2); 2731 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 2732 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 2733 ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(N2); 2734 MVT VT = N->getValueType(0); 2735 MVT VT0 = N0.getValueType(); 2736 2737 // fold select C, X, X -> X 2738 if (N1 == N2) 2739 return N1; 2740 // fold select true, X, Y -> X 2741 if (N0C && !N0C->isNullValue()) 2742 return N1; 2743 // fold select false, X, Y -> Y 2744 if (N0C && N0C->isNullValue()) 2745 return N2; 2746 // fold select C, 1, X -> C | X 2747 if (VT == MVT::i1 && N1C && N1C->getAPIntValue() == 1) 2748 return DAG.getNode(ISD::OR, VT, N0, N2); 2749 // fold select C, 0, 1 -> ~C 2750 if (VT.isInteger() && VT0.isInteger() && 2751 N1C && N2C && N1C->isNullValue() && N2C->getAPIntValue() == 1) { 2752 SDValue XORNode = DAG.getNode(ISD::XOR, VT0, N0, DAG.getConstant(1, VT0)); 2753 if (VT == VT0) 2754 return XORNode; 2755 AddToWorkList(XORNode.getNode()); 2756 if (VT.bitsGT(VT0)) 2757 return DAG.getNode(ISD::ZERO_EXTEND, VT, XORNode); 2758 return DAG.getNode(ISD::TRUNCATE, VT, XORNode); 2759 } 2760 // fold select C, 0, X -> ~C & X 2761 if (VT == VT0 && VT == MVT::i1 && N1C && N1C->isNullValue()) { 2762 SDValue NOTNode = DAG.getNOT(N0, VT); 2763 AddToWorkList(NOTNode.getNode()); 2764 return DAG.getNode(ISD::AND, VT, NOTNode, N2); 2765 } 2766 // fold select C, X, 1 -> ~C | X 2767 if (VT == VT0 && VT == MVT::i1 && N2C && N2C->getAPIntValue() == 1) { 2768 SDValue NOTNode = DAG.getNOT(N0, VT); 2769 AddToWorkList(NOTNode.getNode()); 2770 return DAG.getNode(ISD::OR, VT, NOTNode, N1); 2771 } 2772 // fold select C, X, 0 -> C & X 2773 // FIXME: this should check for C type == X type, not i1? 2774 if (VT == MVT::i1 && N2C && N2C->isNullValue()) 2775 return DAG.getNode(ISD::AND, VT, N0, N1); 2776 // fold X ? X : Y --> X ? 1 : Y --> X | Y 2777 if (VT == MVT::i1 && N0 == N1) 2778 return DAG.getNode(ISD::OR, VT, N0, N2); 2779 // fold X ? Y : X --> X ? Y : 0 --> X & Y 2780 if (VT == MVT::i1 && N0 == N2) 2781 return DAG.getNode(ISD::AND, VT, N0, N1); 2782 2783 // If we can fold this based on the true/false value, do so. 2784 if (SimplifySelectOps(N, N1, N2)) 2785 return SDValue(N, 0); // Don't revisit N. 2786 2787 // fold selects based on a setcc into other things, such as min/max/abs 2788 if (N0.getOpcode() == ISD::SETCC) { 2789 // FIXME: 2790 // Check against MVT::Other for SELECT_CC, which is a workaround for targets 2791 // having to say they don't support SELECT_CC on every type the DAG knows 2792 // about, since there is no way to mark an opcode illegal at all value types 2793 if (TLI.isOperationLegal(ISD::SELECT_CC, MVT::Other)) 2794 return DAG.getNode(ISD::SELECT_CC, VT, N0.getOperand(0), N0.getOperand(1), 2795 N1, N2, N0.getOperand(2)); 2796 else 2797 return SimplifySelect(N0, N1, N2); 2798 } 2799 return SDValue(); 2800} 2801 2802SDValue DAGCombiner::visitSELECT_CC(SDNode *N) { 2803 SDValue N0 = N->getOperand(0); 2804 SDValue N1 = N->getOperand(1); 2805 SDValue N2 = N->getOperand(2); 2806 SDValue N3 = N->getOperand(3); 2807 SDValue N4 = N->getOperand(4); 2808 ISD::CondCode CC = cast<CondCodeSDNode>(N4)->get(); 2809 2810 // fold select_cc lhs, rhs, x, x, cc -> x 2811 if (N2 == N3) 2812 return N2; 2813 2814 // Determine if the condition we're dealing with is constant 2815 SDValue SCC = SimplifySetCC(TLI.getSetCCResultType(N0.getValueType()), 2816 N0, N1, CC, false); 2817 if (SCC.getNode()) AddToWorkList(SCC.getNode()); 2818 2819 if (ConstantSDNode *SCCC = dyn_cast_or_null<ConstantSDNode>(SCC.getNode())) { 2820 if (!SCCC->isNullValue()) 2821 return N2; // cond always true -> true val 2822 else 2823 return N3; // cond always false -> false val 2824 } 2825 2826 // Fold to a simpler select_cc 2827 if (SCC.getNode() && SCC.getOpcode() == ISD::SETCC) 2828 return DAG.getNode(ISD::SELECT_CC, N2.getValueType(), 2829 SCC.getOperand(0), SCC.getOperand(1), N2, N3, 2830 SCC.getOperand(2)); 2831 2832 // If we can fold this based on the true/false value, do so. 2833 if (SimplifySelectOps(N, N2, N3)) 2834 return SDValue(N, 0); // Don't revisit N. 2835 2836 // fold select_cc into other things, such as min/max/abs 2837 return SimplifySelectCC(N0, N1, N2, N3, CC); 2838} 2839 2840SDValue DAGCombiner::visitSETCC(SDNode *N) { 2841 return SimplifySetCC(N->getValueType(0), N->getOperand(0), N->getOperand(1), 2842 cast<CondCodeSDNode>(N->getOperand(2))->get()); 2843} 2844 2845// ExtendUsesToFormExtLoad - Trying to extend uses of a load to enable this: 2846// "fold ({s|z}ext (load x)) -> ({s|z}ext (truncate ({s|z}extload x)))" 2847// transformation. Returns true if extension are possible and the above 2848// mentioned transformation is profitable. 2849static bool ExtendUsesToFormExtLoad(SDNode *N, SDValue N0, 2850 unsigned ExtOpc, 2851 SmallVector<SDNode*, 4> &ExtendNodes, 2852 const TargetLowering &TLI) { 2853 bool HasCopyToRegUses = false; 2854 bool isTruncFree = TLI.isTruncateFree(N->getValueType(0), N0.getValueType()); 2855 for (SDNode::use_iterator UI = N0.getNode()->use_begin(), 2856 UE = N0.getNode()->use_end(); 2857 UI != UE; ++UI) { 2858 SDNode *User = *UI; 2859 if (User == N) 2860 continue; 2861 // FIXME: Only extend SETCC N, N and SETCC N, c for now. 2862 if (User->getOpcode() == ISD::SETCC) { 2863 ISD::CondCode CC = cast<CondCodeSDNode>(User->getOperand(2))->get(); 2864 if (ExtOpc == ISD::ZERO_EXTEND && ISD::isSignedIntSetCC(CC)) 2865 // Sign bits will be lost after a zext. 2866 return false; 2867 bool Add = false; 2868 for (unsigned i = 0; i != 2; ++i) { 2869 SDValue UseOp = User->getOperand(i); 2870 if (UseOp == N0) 2871 continue; 2872 if (!isa<ConstantSDNode>(UseOp)) 2873 return false; 2874 Add = true; 2875 } 2876 if (Add) 2877 ExtendNodes.push_back(User); 2878 } else { 2879 for (unsigned i = 0, e = User->getNumOperands(); i != e; ++i) { 2880 SDValue UseOp = User->getOperand(i); 2881 if (UseOp == N0) { 2882 // If truncate from extended type to original load type is free 2883 // on this target, then it's ok to extend a CopyToReg. 2884 if (isTruncFree && User->getOpcode() == ISD::CopyToReg) 2885 HasCopyToRegUses = true; 2886 else 2887 return false; 2888 } 2889 } 2890 } 2891 } 2892 2893 if (HasCopyToRegUses) { 2894 bool BothLiveOut = false; 2895 for (SDNode::use_iterator UI = N->use_begin(), UE = N->use_end(); 2896 UI != UE; ++UI) { 2897 SDNode *User = *UI; 2898 for (unsigned i = 0, e = User->getNumOperands(); i != e; ++i) { 2899 SDValue UseOp = User->getOperand(i); 2900 if (UseOp.getNode() == N && UseOp.getResNo() == 0) { 2901 BothLiveOut = true; 2902 break; 2903 } 2904 } 2905 } 2906 if (BothLiveOut) 2907 // Both unextended and extended values are live out. There had better be 2908 // good a reason for the transformation. 2909 return ExtendNodes.size(); 2910 } 2911 return true; 2912} 2913 2914SDValue DAGCombiner::visitSIGN_EXTEND(SDNode *N) { 2915 SDValue N0 = N->getOperand(0); 2916 MVT VT = N->getValueType(0); 2917 2918 // fold (sext c1) -> c1 2919 if (isa<ConstantSDNode>(N0)) 2920 return DAG.getNode(ISD::SIGN_EXTEND, VT, N0); 2921 2922 // fold (sext (sext x)) -> (sext x) 2923 // fold (sext (aext x)) -> (sext x) 2924 if (N0.getOpcode() == ISD::SIGN_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND) 2925 return DAG.getNode(ISD::SIGN_EXTEND, VT, N0.getOperand(0)); 2926 2927 if (N0.getOpcode() == ISD::TRUNCATE) { 2928 // fold (sext (truncate (load x))) -> (sext (smaller load x)) 2929 // fold (sext (truncate (srl (load x), c))) -> (sext (smaller load (x+c/n))) 2930 SDValue NarrowLoad = ReduceLoadWidth(N0.getNode()); 2931 if (NarrowLoad.getNode()) { 2932 if (NarrowLoad.getNode() != N0.getNode()) 2933 CombineTo(N0.getNode(), NarrowLoad); 2934 return DAG.getNode(ISD::SIGN_EXTEND, VT, NarrowLoad); 2935 } 2936 2937 // See if the value being truncated is already sign extended. If so, just 2938 // eliminate the trunc/sext pair. 2939 SDValue Op = N0.getOperand(0); 2940 unsigned OpBits = Op.getValueType().getSizeInBits(); 2941 unsigned MidBits = N0.getValueType().getSizeInBits(); 2942 unsigned DestBits = VT.getSizeInBits(); 2943 unsigned NumSignBits = DAG.ComputeNumSignBits(Op); 2944 2945 if (OpBits == DestBits) { 2946 // Op is i32, Mid is i8, and Dest is i32. If Op has more than 24 sign 2947 // bits, it is already ready. 2948 if (NumSignBits > DestBits-MidBits) 2949 return Op; 2950 } else if (OpBits < DestBits) { 2951 // Op is i32, Mid is i8, and Dest is i64. If Op has more than 24 sign 2952 // bits, just sext from i32. 2953 if (NumSignBits > OpBits-MidBits) 2954 return DAG.getNode(ISD::SIGN_EXTEND, VT, Op); 2955 } else { 2956 // Op is i64, Mid is i8, and Dest is i32. If Op has more than 56 sign 2957 // bits, just truncate to i32. 2958 if (NumSignBits > OpBits-MidBits) 2959 return DAG.getNode(ISD::TRUNCATE, VT, Op); 2960 } 2961 2962 // fold (sext (truncate x)) -> (sextinreg x). 2963 if (!LegalOperations || TLI.isOperationLegal(ISD::SIGN_EXTEND_INREG, 2964 N0.getValueType())) { 2965 if (Op.getValueType().bitsLT(VT)) 2966 Op = DAG.getNode(ISD::ANY_EXTEND, VT, Op); 2967 else if (Op.getValueType().bitsGT(VT)) 2968 Op = DAG.getNode(ISD::TRUNCATE, VT, Op); 2969 return DAG.getNode(ISD::SIGN_EXTEND_INREG, VT, Op, 2970 DAG.getValueType(N0.getValueType())); 2971 } 2972 } 2973 2974 // fold (sext (load x)) -> (sext (truncate (sextload x))) 2975 if (ISD::isNON_EXTLoad(N0.getNode()) && 2976 ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) || 2977 TLI.isLoadExtLegal(ISD::SEXTLOAD, N0.getValueType()))) { 2978 bool DoXform = true; 2979 SmallVector<SDNode*, 4> SetCCs; 2980 if (!N0.hasOneUse()) 2981 DoXform = ExtendUsesToFormExtLoad(N, N0, ISD::SIGN_EXTEND, SetCCs, TLI); 2982 if (DoXform) { 2983 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 2984 SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, LN0->getChain(), 2985 LN0->getBasePtr(), LN0->getSrcValue(), 2986 LN0->getSrcValueOffset(), 2987 N0.getValueType(), 2988 LN0->isVolatile(), LN0->getAlignment()); 2989 CombineTo(N, ExtLoad); 2990 SDValue Trunc = DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad); 2991 CombineTo(N0.getNode(), Trunc, ExtLoad.getValue(1)); 2992 // Extend SetCC uses if necessary. 2993 for (unsigned i = 0, e = SetCCs.size(); i != e; ++i) { 2994 SDNode *SetCC = SetCCs[i]; 2995 SmallVector<SDValue, 4> Ops; 2996 for (unsigned j = 0; j != 2; ++j) { 2997 SDValue SOp = SetCC->getOperand(j); 2998 if (SOp == Trunc) 2999 Ops.push_back(ExtLoad); 3000 else 3001 Ops.push_back(DAG.getNode(ISD::SIGN_EXTEND, VT, SOp)); 3002 } 3003 Ops.push_back(SetCC->getOperand(2)); 3004 CombineTo(SetCC, DAG.getNode(ISD::SETCC, SetCC->getValueType(0), 3005 &Ops[0], Ops.size())); 3006 } 3007 return SDValue(N, 0); // Return N so it doesn't get rechecked! 3008 } 3009 } 3010 3011 // fold (sext (sextload x)) -> (sext (truncate (sextload x))) 3012 // fold (sext ( extload x)) -> (sext (truncate (sextload x))) 3013 if ((ISD::isSEXTLoad(N0.getNode()) || ISD::isEXTLoad(N0.getNode())) && 3014 ISD::isUNINDEXEDLoad(N0.getNode()) && N0.hasOneUse()) { 3015 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 3016 MVT EVT = LN0->getMemoryVT(); 3017 if ((!LegalOperations && !LN0->isVolatile()) || 3018 TLI.isLoadExtLegal(ISD::SEXTLOAD, EVT)) { 3019 SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, LN0->getChain(), 3020 LN0->getBasePtr(), LN0->getSrcValue(), 3021 LN0->getSrcValueOffset(), EVT, 3022 LN0->isVolatile(), LN0->getAlignment()); 3023 CombineTo(N, ExtLoad); 3024 CombineTo(N0.getNode(), 3025 DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad), 3026 ExtLoad.getValue(1)); 3027 return SDValue(N, 0); // Return N so it doesn't get rechecked! 3028 } 3029 } 3030 3031 // sext(setcc x,y,cc) -> select_cc x, y, -1, 0, cc 3032 if (N0.getOpcode() == ISD::SETCC) { 3033 SDValue SCC = 3034 SimplifySelectCC(N0.getOperand(0), N0.getOperand(1), 3035 DAG.getConstant(~0ULL, VT), DAG.getConstant(0, VT), 3036 cast<CondCodeSDNode>(N0.getOperand(2))->get(), true); 3037 if (SCC.getNode()) return SCC; 3038 } 3039 3040 // fold (sext x) -> (zext x) if the sign bit is known zero. 3041 if ((!LegalOperations || TLI.isOperationLegal(ISD::ZERO_EXTEND, VT)) && 3042 DAG.SignBitIsZero(N0)) 3043 return DAG.getNode(ISD::ZERO_EXTEND, VT, N0); 3044 3045 return SDValue(); 3046} 3047 3048SDValue DAGCombiner::visitZERO_EXTEND(SDNode *N) { 3049 SDValue N0 = N->getOperand(0); 3050 MVT VT = N->getValueType(0); 3051 3052 // fold (zext c1) -> c1 3053 if (isa<ConstantSDNode>(N0)) 3054 return DAG.getNode(ISD::ZERO_EXTEND, VT, N0); 3055 // fold (zext (zext x)) -> (zext x) 3056 // fold (zext (aext x)) -> (zext x) 3057 if (N0.getOpcode() == ISD::ZERO_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND) 3058 return DAG.getNode(ISD::ZERO_EXTEND, VT, N0.getOperand(0)); 3059 3060 // fold (zext (truncate (load x))) -> (zext (smaller load x)) 3061 // fold (zext (truncate (srl (load x), c))) -> (zext (small load (x+c/n))) 3062 if (N0.getOpcode() == ISD::TRUNCATE) { 3063 SDValue NarrowLoad = ReduceLoadWidth(N0.getNode()); 3064 if (NarrowLoad.getNode()) { 3065 if (NarrowLoad.getNode() != N0.getNode()) 3066 CombineTo(N0.getNode(), NarrowLoad); 3067 return DAG.getNode(ISD::ZERO_EXTEND, VT, NarrowLoad); 3068 } 3069 } 3070 3071 // fold (zext (truncate x)) -> (and x, mask) 3072 if (N0.getOpcode() == ISD::TRUNCATE && 3073 (!LegalOperations || TLI.isOperationLegal(ISD::AND, VT))) { 3074 SDValue Op = N0.getOperand(0); 3075 if (Op.getValueType().bitsLT(VT)) { 3076 Op = DAG.getNode(ISD::ANY_EXTEND, VT, Op); 3077 } else if (Op.getValueType().bitsGT(VT)) { 3078 Op = DAG.getNode(ISD::TRUNCATE, VT, Op); 3079 } 3080 return DAG.getZeroExtendInReg(Op, N0.getValueType()); 3081 } 3082 3083 // fold (zext (and (trunc x), cst)) -> (and x, cst). 3084 if (N0.getOpcode() == ISD::AND && 3085 N0.getOperand(0).getOpcode() == ISD::TRUNCATE && 3086 N0.getOperand(1).getOpcode() == ISD::Constant) { 3087 SDValue X = N0.getOperand(0).getOperand(0); 3088 if (X.getValueType().bitsLT(VT)) { 3089 X = DAG.getNode(ISD::ANY_EXTEND, VT, X); 3090 } else if (X.getValueType().bitsGT(VT)) { 3091 X = DAG.getNode(ISD::TRUNCATE, VT, X); 3092 } 3093 APInt Mask = cast<ConstantSDNode>(N0.getOperand(1))->getAPIntValue(); 3094 Mask.zext(VT.getSizeInBits()); 3095 return DAG.getNode(ISD::AND, VT, X, DAG.getConstant(Mask, VT)); 3096 } 3097 3098 // fold (zext (load x)) -> (zext (truncate (zextload x))) 3099 if (ISD::isNON_EXTLoad(N0.getNode()) && 3100 ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) || 3101 TLI.isLoadExtLegal(ISD::ZEXTLOAD, N0.getValueType()))) { 3102 bool DoXform = true; 3103 SmallVector<SDNode*, 4> SetCCs; 3104 if (!N0.hasOneUse()) 3105 DoXform = ExtendUsesToFormExtLoad(N, N0, ISD::ZERO_EXTEND, SetCCs, TLI); 3106 if (DoXform) { 3107 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 3108 SDValue ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, LN0->getChain(), 3109 LN0->getBasePtr(), LN0->getSrcValue(), 3110 LN0->getSrcValueOffset(), 3111 N0.getValueType(), 3112 LN0->isVolatile(), LN0->getAlignment()); 3113 CombineTo(N, ExtLoad); 3114 SDValue Trunc = DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad); 3115 CombineTo(N0.getNode(), Trunc, ExtLoad.getValue(1)); 3116 // Extend SetCC uses if necessary. 3117 for (unsigned i = 0, e = SetCCs.size(); i != e; ++i) { 3118 SDNode *SetCC = SetCCs[i]; 3119 SmallVector<SDValue, 4> Ops; 3120 for (unsigned j = 0; j != 2; ++j) { 3121 SDValue SOp = SetCC->getOperand(j); 3122 if (SOp == Trunc) 3123 Ops.push_back(ExtLoad); 3124 else 3125 Ops.push_back(DAG.getNode(ISD::ZERO_EXTEND, VT, SOp)); 3126 } 3127 Ops.push_back(SetCC->getOperand(2)); 3128 CombineTo(SetCC, DAG.getNode(ISD::SETCC, SetCC->getValueType(0), 3129 &Ops[0], Ops.size())); 3130 } 3131 return SDValue(N, 0); // Return N so it doesn't get rechecked! 3132 } 3133 } 3134 3135 // fold (zext (zextload x)) -> (zext (truncate (zextload x))) 3136 // fold (zext ( extload x)) -> (zext (truncate (zextload x))) 3137 if ((ISD::isZEXTLoad(N0.getNode()) || ISD::isEXTLoad(N0.getNode())) && 3138 ISD::isUNINDEXEDLoad(N0.getNode()) && N0.hasOneUse()) { 3139 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 3140 MVT EVT = LN0->getMemoryVT(); 3141 if ((!LegalOperations && !LN0->isVolatile()) || 3142 TLI.isLoadExtLegal(ISD::ZEXTLOAD, EVT)) { 3143 SDValue ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, LN0->getChain(), 3144 LN0->getBasePtr(), LN0->getSrcValue(), 3145 LN0->getSrcValueOffset(), EVT, 3146 LN0->isVolatile(), LN0->getAlignment()); 3147 CombineTo(N, ExtLoad); 3148 CombineTo(N0.getNode(), 3149 DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad), 3150 ExtLoad.getValue(1)); 3151 return SDValue(N, 0); // Return N so it doesn't get rechecked! 3152 } 3153 } 3154 3155 // zext(setcc x,y,cc) -> select_cc x, y, 1, 0, cc 3156 if (N0.getOpcode() == ISD::SETCC) { 3157 SDValue SCC = 3158 SimplifySelectCC(N0.getOperand(0), N0.getOperand(1), 3159 DAG.getConstant(1, VT), DAG.getConstant(0, VT), 3160 cast<CondCodeSDNode>(N0.getOperand(2))->get(), true); 3161 if (SCC.getNode()) return SCC; 3162 } 3163 3164 return SDValue(); 3165} 3166 3167SDValue DAGCombiner::visitANY_EXTEND(SDNode *N) { 3168 SDValue N0 = N->getOperand(0); 3169 MVT VT = N->getValueType(0); 3170 3171 // fold (aext c1) -> c1 3172 if (isa<ConstantSDNode>(N0)) 3173 return DAG.getNode(ISD::ANY_EXTEND, VT, N0); 3174 // fold (aext (aext x)) -> (aext x) 3175 // fold (aext (zext x)) -> (zext x) 3176 // fold (aext (sext x)) -> (sext x) 3177 if (N0.getOpcode() == ISD::ANY_EXTEND || 3178 N0.getOpcode() == ISD::ZERO_EXTEND || 3179 N0.getOpcode() == ISD::SIGN_EXTEND) 3180 return DAG.getNode(N0.getOpcode(), VT, N0.getOperand(0)); 3181 3182 // fold (aext (truncate (load x))) -> (aext (smaller load x)) 3183 // fold (aext (truncate (srl (load x), c))) -> (aext (small load (x+c/n))) 3184 if (N0.getOpcode() == ISD::TRUNCATE) { 3185 SDValue NarrowLoad = ReduceLoadWidth(N0.getNode()); 3186 if (NarrowLoad.getNode()) { 3187 if (NarrowLoad.getNode() != N0.getNode()) 3188 CombineTo(N0.getNode(), NarrowLoad); 3189 return DAG.getNode(ISD::ANY_EXTEND, VT, NarrowLoad); 3190 } 3191 } 3192 3193 // fold (aext (truncate x)) 3194 if (N0.getOpcode() == ISD::TRUNCATE) { 3195 SDValue TruncOp = N0.getOperand(0); 3196 if (TruncOp.getValueType() == VT) 3197 return TruncOp; // x iff x size == zext size. 3198 if (TruncOp.getValueType().bitsGT(VT)) 3199 return DAG.getNode(ISD::TRUNCATE, VT, TruncOp); 3200 return DAG.getNode(ISD::ANY_EXTEND, VT, TruncOp); 3201 } 3202 3203 // fold (aext (and (trunc x), cst)) -> (and x, cst). 3204 if (N0.getOpcode() == ISD::AND && 3205 N0.getOperand(0).getOpcode() == ISD::TRUNCATE && 3206 N0.getOperand(1).getOpcode() == ISD::Constant) { 3207 SDValue X = N0.getOperand(0).getOperand(0); 3208 if (X.getValueType().bitsLT(VT)) { 3209 X = DAG.getNode(ISD::ANY_EXTEND, VT, X); 3210 } else if (X.getValueType().bitsGT(VT)) { 3211 X = DAG.getNode(ISD::TRUNCATE, VT, X); 3212 } 3213 APInt Mask = cast<ConstantSDNode>(N0.getOperand(1))->getAPIntValue(); 3214 Mask.zext(VT.getSizeInBits()); 3215 return DAG.getNode(ISD::AND, VT, X, DAG.getConstant(Mask, VT)); 3216 } 3217 3218 // fold (aext (load x)) -> (aext (truncate (extload x))) 3219 if (ISD::isNON_EXTLoad(N0.getNode()) && N0.hasOneUse() && 3220 ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) || 3221 TLI.isLoadExtLegal(ISD::EXTLOAD, N0.getValueType()))) { 3222 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 3223 SDValue ExtLoad = DAG.getExtLoad(ISD::EXTLOAD, VT, LN0->getChain(), 3224 LN0->getBasePtr(), LN0->getSrcValue(), 3225 LN0->getSrcValueOffset(), 3226 N0.getValueType(), 3227 LN0->isVolatile(), LN0->getAlignment()); 3228 CombineTo(N, ExtLoad); 3229 // Redirect any chain users to the new load. 3230 DAG.ReplaceAllUsesOfValueWith(SDValue(LN0, 1), 3231 SDValue(ExtLoad.getNode(), 1)); 3232 // If any node needs the original loaded value, recompute it. 3233 if (!LN0->use_empty()) 3234 CombineTo(LN0, DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad), 3235 ExtLoad.getValue(1)); 3236 return SDValue(N, 0); // Return N so it doesn't get rechecked! 3237 } 3238 3239 // fold (aext (zextload x)) -> (aext (truncate (zextload x))) 3240 // fold (aext (sextload x)) -> (aext (truncate (sextload x))) 3241 // fold (aext ( extload x)) -> (aext (truncate (extload x))) 3242 if (N0.getOpcode() == ISD::LOAD && 3243 !ISD::isNON_EXTLoad(N0.getNode()) && ISD::isUNINDEXEDLoad(N0.getNode()) && 3244 N0.hasOneUse()) { 3245 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 3246 MVT EVT = LN0->getMemoryVT(); 3247 SDValue ExtLoad = DAG.getExtLoad(LN0->getExtensionType(), VT, 3248 LN0->getChain(), LN0->getBasePtr(), 3249 LN0->getSrcValue(), 3250 LN0->getSrcValueOffset(), EVT, 3251 LN0->isVolatile(), LN0->getAlignment()); 3252 CombineTo(N, ExtLoad); 3253 CombineTo(N0.getNode(), 3254 DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad), 3255 ExtLoad.getValue(1)); 3256 return SDValue(N, 0); // Return N so it doesn't get rechecked! 3257 } 3258 3259 // aext(setcc x,y,cc) -> select_cc x, y, 1, 0, cc 3260 if (N0.getOpcode() == ISD::SETCC) { 3261 SDValue SCC = 3262 SimplifySelectCC(N0.getOperand(0), N0.getOperand(1), 3263 DAG.getConstant(1, VT), DAG.getConstant(0, VT), 3264 cast<CondCodeSDNode>(N0.getOperand(2))->get(), true); 3265 if (SCC.getNode()) 3266 return SCC; 3267 } 3268 3269 return SDValue(); 3270} 3271 3272/// GetDemandedBits - See if the specified operand can be simplified with the 3273/// knowledge that only the bits specified by Mask are used. If so, return the 3274/// simpler operand, otherwise return a null SDValue. 3275SDValue DAGCombiner::GetDemandedBits(SDValue V, const APInt &Mask) { 3276 switch (V.getOpcode()) { 3277 default: break; 3278 case ISD::OR: 3279 case ISD::XOR: 3280 // If the LHS or RHS don't contribute bits to the or, drop them. 3281 if (DAG.MaskedValueIsZero(V.getOperand(0), Mask)) 3282 return V.getOperand(1); 3283 if (DAG.MaskedValueIsZero(V.getOperand(1), Mask)) 3284 return V.getOperand(0); 3285 break; 3286 case ISD::SRL: 3287 // Only look at single-use SRLs. 3288 if (!V.getNode()->hasOneUse()) 3289 break; 3290 if (ConstantSDNode *RHSC = dyn_cast<ConstantSDNode>(V.getOperand(1))) { 3291 // See if we can recursively simplify the LHS. 3292 unsigned Amt = RHSC->getZExtValue(); 3293 // Watch out for shift count overflow though. 3294 if (Amt >= Mask.getBitWidth()) break; 3295 APInt NewMask = Mask << Amt; 3296 SDValue SimplifyLHS = GetDemandedBits(V.getOperand(0), NewMask); 3297 if (SimplifyLHS.getNode()) { 3298 return DAG.getNode(ISD::SRL, V.getValueType(), 3299 SimplifyLHS, V.getOperand(1)); 3300 } 3301 } 3302 } 3303 return SDValue(); 3304} 3305 3306/// ReduceLoadWidth - If the result of a wider load is shifted to right of N 3307/// bits and then truncated to a narrower type and where N is a multiple 3308/// of number of bits of the narrower type, transform it to a narrower load 3309/// from address + N / num of bits of new type. If the result is to be 3310/// extended, also fold the extension to form a extending load. 3311SDValue DAGCombiner::ReduceLoadWidth(SDNode *N) { 3312 unsigned Opc = N->getOpcode(); 3313 ISD::LoadExtType ExtType = ISD::NON_EXTLOAD; 3314 SDValue N0 = N->getOperand(0); 3315 MVT VT = N->getValueType(0); 3316 MVT EVT = VT; 3317 3318 // This transformation isn't valid for vector loads. 3319 if (VT.isVector()) 3320 return SDValue(); 3321 3322 // Special case: SIGN_EXTEND_INREG is basically truncating to EVT then 3323 // extended to VT. 3324 if (Opc == ISD::SIGN_EXTEND_INREG) { 3325 ExtType = ISD::SEXTLOAD; 3326 EVT = cast<VTSDNode>(N->getOperand(1))->getVT(); 3327 if (LegalOperations && !TLI.isLoadExtLegal(ISD::SEXTLOAD, EVT)) 3328 return SDValue(); 3329 } 3330 3331 unsigned EVTBits = EVT.getSizeInBits(); 3332 unsigned ShAmt = 0; 3333 if (N0.getOpcode() == ISD::SRL && N0.hasOneUse()) { 3334 if (ConstantSDNode *N01 = dyn_cast<ConstantSDNode>(N0.getOperand(1))) { 3335 ShAmt = N01->getZExtValue(); 3336 // Is the shift amount a multiple of size of VT? 3337 if ((ShAmt & (EVTBits-1)) == 0) { 3338 N0 = N0.getOperand(0); 3339 if (N0.getValueType().getSizeInBits() <= EVTBits) 3340 return SDValue(); 3341 } 3342 } 3343 } 3344 3345 // Do not generate loads of non-round integer types since these can 3346 // be expensive (and would be wrong if the type is not byte sized). 3347 if (isa<LoadSDNode>(N0) && N0.hasOneUse() && EVT.isRound() && 3348 cast<LoadSDNode>(N0)->getMemoryVT().getSizeInBits() > EVTBits && 3349 // Do not change the width of a volatile load. 3350 !cast<LoadSDNode>(N0)->isVolatile()) { 3351 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 3352 MVT PtrType = N0.getOperand(1).getValueType(); 3353 // For big endian targets, we need to adjust the offset to the pointer to 3354 // load the correct bytes. 3355 if (TLI.isBigEndian()) { 3356 unsigned LVTStoreBits = LN0->getMemoryVT().getStoreSizeInBits(); 3357 unsigned EVTStoreBits = EVT.getStoreSizeInBits(); 3358 ShAmt = LVTStoreBits - EVTStoreBits - ShAmt; 3359 } 3360 uint64_t PtrOff = ShAmt / 8; 3361 unsigned NewAlign = MinAlign(LN0->getAlignment(), PtrOff); 3362 SDValue NewPtr = DAG.getNode(ISD::ADD, PtrType, LN0->getBasePtr(), 3363 DAG.getConstant(PtrOff, PtrType)); 3364 AddToWorkList(NewPtr.getNode()); 3365 SDValue Load = (ExtType == ISD::NON_EXTLOAD) 3366 ? DAG.getLoad(VT, LN0->getChain(), NewPtr, 3367 LN0->getSrcValue(), LN0->getSrcValueOffset() + PtrOff, 3368 LN0->isVolatile(), NewAlign) 3369 : DAG.getExtLoad(ExtType, VT, LN0->getChain(), NewPtr, 3370 LN0->getSrcValue(), LN0->getSrcValueOffset() + PtrOff, 3371 EVT, LN0->isVolatile(), NewAlign); 3372 // Replace the old load's chain with the new load's chain. 3373 WorkListRemover DeadNodes(*this); 3374 DAG.ReplaceAllUsesOfValueWith(N0.getValue(1), Load.getValue(1), 3375 &DeadNodes); 3376 // Return the new loaded value. 3377 return Load; 3378 } 3379 3380 return SDValue(); 3381} 3382 3383 3384SDValue DAGCombiner::visitSIGN_EXTEND_INREG(SDNode *N) { 3385 SDValue N0 = N->getOperand(0); 3386 SDValue N1 = N->getOperand(1); 3387 MVT VT = N->getValueType(0); 3388 MVT EVT = cast<VTSDNode>(N1)->getVT(); 3389 unsigned VTBits = VT.getSizeInBits(); 3390 unsigned EVTBits = EVT.getSizeInBits(); 3391 3392 // fold (sext_in_reg c1) -> c1 3393 if (isa<ConstantSDNode>(N0) || N0.getOpcode() == ISD::UNDEF) 3394 return DAG.getNode(ISD::SIGN_EXTEND_INREG, VT, N0, N1); 3395 3396 // If the input is already sign extended, just drop the extension. 3397 if (DAG.ComputeNumSignBits(N0) >= VT.getSizeInBits()-EVTBits+1) 3398 return N0; 3399 3400 // fold (sext_in_reg (sext_in_reg x, VT2), VT1) -> (sext_in_reg x, minVT) pt2 3401 if (N0.getOpcode() == ISD::SIGN_EXTEND_INREG && 3402 EVT.bitsLT(cast<VTSDNode>(N0.getOperand(1))->getVT())) { 3403 return DAG.getNode(ISD::SIGN_EXTEND_INREG, VT, N0.getOperand(0), N1); 3404 } 3405 3406 // fold (sext_in_reg (sext x)) -> (sext x) 3407 // fold (sext_in_reg (aext x)) -> (sext x) 3408 // if x is small enough. 3409 if (N0.getOpcode() == ISD::SIGN_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND) { 3410 SDValue N00 = N0.getOperand(0); 3411 if (N00.getValueType().getSizeInBits() < EVTBits) 3412 return DAG.getNode(ISD::SIGN_EXTEND, VT, N00, N1); 3413 } 3414 3415 // fold (sext_in_reg x) -> (zext_in_reg x) if the sign bit is known zero. 3416 if (DAG.MaskedValueIsZero(N0, APInt::getBitsSet(VTBits, EVTBits-1, EVTBits))) 3417 return DAG.getZeroExtendInReg(N0, EVT); 3418 3419 // fold operands of sext_in_reg based on knowledge that the top bits are not 3420 // demanded. 3421 if (SimplifyDemandedBits(SDValue(N, 0))) 3422 return SDValue(N, 0); 3423 3424 // fold (sext_in_reg (load x)) -> (smaller sextload x) 3425 // fold (sext_in_reg (srl (load x), c)) -> (smaller sextload (x+c/evtbits)) 3426 SDValue NarrowLoad = ReduceLoadWidth(N); 3427 if (NarrowLoad.getNode()) 3428 return NarrowLoad; 3429 3430 // fold (sext_in_reg (srl X, 24), i8) -> sra X, 24 3431 // fold (sext_in_reg (srl X, 23), i8) -> sra X, 23 iff possible. 3432 // We already fold "(sext_in_reg (srl X, 25), i8) -> srl X, 25" above. 3433 if (N0.getOpcode() == ISD::SRL) { 3434 if (ConstantSDNode *ShAmt = dyn_cast<ConstantSDNode>(N0.getOperand(1))) 3435 if (ShAmt->getZExtValue()+EVTBits <= VT.getSizeInBits()) { 3436 // We can turn this into an SRA iff the input to the SRL is already sign 3437 // extended enough. 3438 unsigned InSignBits = DAG.ComputeNumSignBits(N0.getOperand(0)); 3439 if (VT.getSizeInBits()-(ShAmt->getZExtValue()+EVTBits) < InSignBits) 3440 return DAG.getNode(ISD::SRA, VT, N0.getOperand(0), N0.getOperand(1)); 3441 } 3442 } 3443 3444 // fold (sext_inreg (extload x)) -> (sextload x) 3445 if (ISD::isEXTLoad(N0.getNode()) && 3446 ISD::isUNINDEXEDLoad(N0.getNode()) && 3447 EVT == cast<LoadSDNode>(N0)->getMemoryVT() && 3448 ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) || 3449 TLI.isLoadExtLegal(ISD::SEXTLOAD, EVT))) { 3450 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 3451 SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, LN0->getChain(), 3452 LN0->getBasePtr(), LN0->getSrcValue(), 3453 LN0->getSrcValueOffset(), EVT, 3454 LN0->isVolatile(), LN0->getAlignment()); 3455 CombineTo(N, ExtLoad); 3456 CombineTo(N0.getNode(), ExtLoad, ExtLoad.getValue(1)); 3457 return SDValue(N, 0); // Return N so it doesn't get rechecked! 3458 } 3459 // fold (sext_inreg (zextload x)) -> (sextload x) iff load has one use 3460 if (ISD::isZEXTLoad(N0.getNode()) && ISD::isUNINDEXEDLoad(N0.getNode()) && 3461 N0.hasOneUse() && 3462 EVT == cast<LoadSDNode>(N0)->getMemoryVT() && 3463 ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) || 3464 TLI.isLoadExtLegal(ISD::SEXTLOAD, EVT))) { 3465 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 3466 SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, LN0->getChain(), 3467 LN0->getBasePtr(), LN0->getSrcValue(), 3468 LN0->getSrcValueOffset(), EVT, 3469 LN0->isVolatile(), LN0->getAlignment()); 3470 CombineTo(N, ExtLoad); 3471 CombineTo(N0.getNode(), ExtLoad, ExtLoad.getValue(1)); 3472 return SDValue(N, 0); // Return N so it doesn't get rechecked! 3473 } 3474 return SDValue(); 3475} 3476 3477SDValue DAGCombiner::visitTRUNCATE(SDNode *N) { 3478 SDValue N0 = N->getOperand(0); 3479 MVT VT = N->getValueType(0); 3480 3481 // noop truncate 3482 if (N0.getValueType() == N->getValueType(0)) 3483 return N0; 3484 // fold (truncate c1) -> c1 3485 if (isa<ConstantSDNode>(N0)) 3486 return DAG.getNode(ISD::TRUNCATE, VT, N0); 3487 // fold (truncate (truncate x)) -> (truncate x) 3488 if (N0.getOpcode() == ISD::TRUNCATE) 3489 return DAG.getNode(ISD::TRUNCATE, VT, N0.getOperand(0)); 3490 // fold (truncate (ext x)) -> (ext x) or (truncate x) or x 3491 if (N0.getOpcode() == ISD::ZERO_EXTEND || N0.getOpcode() == ISD::SIGN_EXTEND|| 3492 N0.getOpcode() == ISD::ANY_EXTEND) { 3493 if (N0.getOperand(0).getValueType().bitsLT(VT)) 3494 // if the source is smaller than the dest, we still need an extend 3495 return DAG.getNode(N0.getOpcode(), VT, N0.getOperand(0)); 3496 else if (N0.getOperand(0).getValueType().bitsGT(VT)) 3497 // if the source is larger than the dest, than we just need the truncate 3498 return DAG.getNode(ISD::TRUNCATE, VT, N0.getOperand(0)); 3499 else 3500 // if the source and dest are the same type, we can drop both the extend 3501 // and the truncate 3502 return N0.getOperand(0); 3503 } 3504 3505 // See if we can simplify the input to this truncate through knowledge that 3506 // only the low bits are being used. For example "trunc (or (shl x, 8), y)" 3507 // -> trunc y 3508 SDValue Shorter = 3509 GetDemandedBits(N0, APInt::getLowBitsSet(N0.getValueSizeInBits(), 3510 VT.getSizeInBits())); 3511 if (Shorter.getNode()) 3512 return DAG.getNode(ISD::TRUNCATE, VT, Shorter); 3513 3514 // fold (truncate (load x)) -> (smaller load x) 3515 // fold (truncate (srl (load x), c)) -> (smaller load (x+c/evtbits)) 3516 return ReduceLoadWidth(N); 3517} 3518 3519static SDNode *getBuildPairElt(SDNode *N, unsigned i) { 3520 SDValue Elt = N->getOperand(i); 3521 if (Elt.getOpcode() != ISD::MERGE_VALUES) 3522 return Elt.getNode(); 3523 return Elt.getOperand(Elt.getResNo()).getNode(); 3524} 3525 3526/// CombineConsecutiveLoads - build_pair (load, load) -> load 3527/// if load locations are consecutive. 3528SDValue DAGCombiner::CombineConsecutiveLoads(SDNode *N, MVT VT) { 3529 assert(N->getOpcode() == ISD::BUILD_PAIR); 3530 3531 SDNode *LD1 = getBuildPairElt(N, 0); 3532 if (!ISD::isNON_EXTLoad(LD1) || !LD1->hasOneUse()) 3533 return SDValue(); 3534 MVT LD1VT = LD1->getValueType(0); 3535 SDNode *LD2 = getBuildPairElt(N, 1); 3536 const MachineFrameInfo *MFI = DAG.getMachineFunction().getFrameInfo(); 3537 if (ISD::isNON_EXTLoad(LD2) && 3538 LD2->hasOneUse() && 3539 // If both are volatile this would reduce the number of volatile loads. 3540 // If one is volatile it might be ok, but play conservative and bail out. 3541 !cast<LoadSDNode>(LD1)->isVolatile() && 3542 !cast<LoadSDNode>(LD2)->isVolatile() && 3543 TLI.isConsecutiveLoad(LD2, LD1, LD1VT.getSizeInBits()/8, 1, MFI)) { 3544 LoadSDNode *LD = cast<LoadSDNode>(LD1); 3545 unsigned Align = LD->getAlignment(); 3546 unsigned NewAlign = TLI.getTargetData()-> 3547 getABITypeAlignment(VT.getTypeForMVT()); 3548 if (NewAlign <= Align && 3549 (!LegalOperations || TLI.isOperationLegal(ISD::LOAD, VT))) 3550 return DAG.getLoad(VT, LD->getChain(), LD->getBasePtr(), 3551 LD->getSrcValue(), LD->getSrcValueOffset(), 3552 false, Align); 3553 } 3554 return SDValue(); 3555} 3556 3557SDValue DAGCombiner::visitBIT_CONVERT(SDNode *N) { 3558 SDValue N0 = N->getOperand(0); 3559 MVT VT = N->getValueType(0); 3560 3561 // If the input is a BUILD_VECTOR with all constant elements, fold this now. 3562 // Only do this before legalize, since afterward the target may be depending 3563 // on the bitconvert. 3564 // First check to see if this is all constant. 3565 if (!LegalTypes && 3566 N0.getOpcode() == ISD::BUILD_VECTOR && N0.getNode()->hasOneUse() && 3567 VT.isVector()) { 3568 bool isSimple = true; 3569 for (unsigned i = 0, e = N0.getNumOperands(); i != e; ++i) 3570 if (N0.getOperand(i).getOpcode() != ISD::UNDEF && 3571 N0.getOperand(i).getOpcode() != ISD::Constant && 3572 N0.getOperand(i).getOpcode() != ISD::ConstantFP) { 3573 isSimple = false; 3574 break; 3575 } 3576 3577 MVT DestEltVT = N->getValueType(0).getVectorElementType(); 3578 assert(!DestEltVT.isVector() && 3579 "Element type of vector ValueType must not be vector!"); 3580 if (isSimple) { 3581 return ConstantFoldBIT_CONVERTofBUILD_VECTOR(N0.getNode(), DestEltVT); 3582 } 3583 } 3584 3585 // If the input is a constant, let getNode fold it. 3586 if (isa<ConstantSDNode>(N0) || isa<ConstantFPSDNode>(N0)) { 3587 SDValue Res = DAG.getNode(ISD::BIT_CONVERT, VT, N0); 3588 if (Res.getNode() != N) return Res; 3589 } 3590 3591 if (N0.getOpcode() == ISD::BIT_CONVERT) // conv(conv(x,t1),t2) -> conv(x,t2) 3592 return DAG.getNode(ISD::BIT_CONVERT, VT, N0.getOperand(0)); 3593 3594 // fold (conv (load x)) -> (load (conv*)x) 3595 // If the resultant load doesn't need a higher alignment than the original! 3596 if (ISD::isNormalLoad(N0.getNode()) && N0.hasOneUse() && 3597 // Do not change the width of a volatile load. 3598 !cast<LoadSDNode>(N0)->isVolatile() && 3599 (!LegalOperations || TLI.isOperationLegal(ISD::LOAD, VT))) { 3600 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 3601 unsigned Align = TLI.getTargetData()-> 3602 getABITypeAlignment(VT.getTypeForMVT()); 3603 unsigned OrigAlign = LN0->getAlignment(); 3604 if (Align <= OrigAlign) { 3605 SDValue Load = DAG.getLoad(VT, LN0->getChain(), LN0->getBasePtr(), 3606 LN0->getSrcValue(), LN0->getSrcValueOffset(), 3607 LN0->isVolatile(), OrigAlign); 3608 AddToWorkList(N); 3609 CombineTo(N0.getNode(), 3610 DAG.getNode(ISD::BIT_CONVERT, N0.getValueType(), Load), 3611 Load.getValue(1)); 3612 return Load; 3613 } 3614 } 3615 3616 // Fold bitconvert(fneg(x)) -> xor(bitconvert(x), signbit) 3617 // Fold bitconvert(fabs(x)) -> and(bitconvert(x), ~signbit) 3618 // This often reduces constant pool loads. 3619 if ((N0.getOpcode() == ISD::FNEG || N0.getOpcode() == ISD::FABS) && 3620 N0.getNode()->hasOneUse() && VT.isInteger() && !VT.isVector()) { 3621 SDValue NewConv = DAG.getNode(ISD::BIT_CONVERT, VT, N0.getOperand(0)); 3622 AddToWorkList(NewConv.getNode()); 3623 3624 APInt SignBit = APInt::getSignBit(VT.getSizeInBits()); 3625 if (N0.getOpcode() == ISD::FNEG) 3626 return DAG.getNode(ISD::XOR, VT, NewConv, DAG.getConstant(SignBit, VT)); 3627 assert(N0.getOpcode() == ISD::FABS); 3628 return DAG.getNode(ISD::AND, VT, NewConv, DAG.getConstant(~SignBit, VT)); 3629 } 3630 3631 // Fold bitconvert(fcopysign(cst, x)) -> bitconvert(x)&sign | cst&~sign' 3632 // Note that we don't handle copysign(x,cst) because this can always be folded 3633 // to an fneg or fabs. 3634 if (N0.getOpcode() == ISD::FCOPYSIGN && N0.getNode()->hasOneUse() && 3635 isa<ConstantFPSDNode>(N0.getOperand(0)) && 3636 VT.isInteger() && !VT.isVector()) { 3637 unsigned OrigXWidth = N0.getOperand(1).getValueType().getSizeInBits(); 3638 MVT IntXVT = MVT::getIntegerVT(OrigXWidth); 3639 if (TLI.isTypeLegal(IntXVT) || !LegalTypes) { 3640 SDValue X = DAG.getNode(ISD::BIT_CONVERT, IntXVT, N0.getOperand(1)); 3641 AddToWorkList(X.getNode()); 3642 3643 // If X has a different width than the result/lhs, sext it or truncate it. 3644 unsigned VTWidth = VT.getSizeInBits(); 3645 if (OrigXWidth < VTWidth) { 3646 X = DAG.getNode(ISD::SIGN_EXTEND, VT, X); 3647 AddToWorkList(X.getNode()); 3648 } else if (OrigXWidth > VTWidth) { 3649 // To get the sign bit in the right place, we have to shift it right 3650 // before truncating. 3651 X = DAG.getNode(ISD::SRL, X.getValueType(), X, 3652 DAG.getConstant(OrigXWidth-VTWidth, X.getValueType())); 3653 AddToWorkList(X.getNode()); 3654 X = DAG.getNode(ISD::TRUNCATE, VT, X); 3655 AddToWorkList(X.getNode()); 3656 } 3657 3658 APInt SignBit = APInt::getSignBit(VT.getSizeInBits()); 3659 X = DAG.getNode(ISD::AND, VT, X, DAG.getConstant(SignBit, VT)); 3660 AddToWorkList(X.getNode()); 3661 3662 SDValue Cst = DAG.getNode(ISD::BIT_CONVERT, VT, N0.getOperand(0)); 3663 Cst = DAG.getNode(ISD::AND, VT, Cst, DAG.getConstant(~SignBit, VT)); 3664 AddToWorkList(Cst.getNode()); 3665 3666 return DAG.getNode(ISD::OR, VT, X, Cst); 3667 } 3668 } 3669 3670 // bitconvert(build_pair(ld, ld)) -> ld iff load locations are consecutive. 3671 if (N0.getOpcode() == ISD::BUILD_PAIR) { 3672 SDValue CombineLD = CombineConsecutiveLoads(N0.getNode(), VT); 3673 if (CombineLD.getNode()) 3674 return CombineLD; 3675 } 3676 3677 return SDValue(); 3678} 3679 3680SDValue DAGCombiner::visitBUILD_PAIR(SDNode *N) { 3681 MVT VT = N->getValueType(0); 3682 return CombineConsecutiveLoads(N, VT); 3683} 3684 3685/// ConstantFoldBIT_CONVERTofBUILD_VECTOR - We know that BV is a build_vector 3686/// node with Constant, ConstantFP or Undef operands. DstEltVT indicates the 3687/// destination element value type. 3688SDValue DAGCombiner:: 3689ConstantFoldBIT_CONVERTofBUILD_VECTOR(SDNode *BV, MVT DstEltVT) { 3690 MVT SrcEltVT = BV->getOperand(0).getValueType(); 3691 3692 // If this is already the right type, we're done. 3693 if (SrcEltVT == DstEltVT) return SDValue(BV, 0); 3694 3695 unsigned SrcBitSize = SrcEltVT.getSizeInBits(); 3696 unsigned DstBitSize = DstEltVT.getSizeInBits(); 3697 3698 // If this is a conversion of N elements of one type to N elements of another 3699 // type, convert each element. This handles FP<->INT cases. 3700 if (SrcBitSize == DstBitSize) { 3701 SmallVector<SDValue, 8> Ops; 3702 for (unsigned i = 0, e = BV->getNumOperands(); i != e; ++i) { 3703 Ops.push_back(DAG.getNode(ISD::BIT_CONVERT, DstEltVT, BV->getOperand(i))); 3704 AddToWorkList(Ops.back().getNode()); 3705 } 3706 MVT VT = MVT::getVectorVT(DstEltVT, 3707 BV->getValueType(0).getVectorNumElements()); 3708 return DAG.getNode(ISD::BUILD_VECTOR, VT, &Ops[0], Ops.size()); 3709 } 3710 3711 // Otherwise, we're growing or shrinking the elements. To avoid having to 3712 // handle annoying details of growing/shrinking FP values, we convert them to 3713 // int first. 3714 if (SrcEltVT.isFloatingPoint()) { 3715 // Convert the input float vector to a int vector where the elements are the 3716 // same sizes. 3717 assert((SrcEltVT == MVT::f32 || SrcEltVT == MVT::f64) && "Unknown FP VT!"); 3718 MVT IntVT = MVT::getIntegerVT(SrcEltVT.getSizeInBits()); 3719 BV = ConstantFoldBIT_CONVERTofBUILD_VECTOR(BV, IntVT).getNode(); 3720 SrcEltVT = IntVT; 3721 } 3722 3723 // Now we know the input is an integer vector. If the output is a FP type, 3724 // convert to integer first, then to FP of the right size. 3725 if (DstEltVT.isFloatingPoint()) { 3726 assert((DstEltVT == MVT::f32 || DstEltVT == MVT::f64) && "Unknown FP VT!"); 3727 MVT TmpVT = MVT::getIntegerVT(DstEltVT.getSizeInBits()); 3728 SDNode *Tmp = ConstantFoldBIT_CONVERTofBUILD_VECTOR(BV, TmpVT).getNode(); 3729 3730 // Next, convert to FP elements of the same size. 3731 return ConstantFoldBIT_CONVERTofBUILD_VECTOR(Tmp, DstEltVT); 3732 } 3733 3734 // Okay, we know the src/dst types are both integers of differing types. 3735 // Handling growing first. 3736 assert(SrcEltVT.isInteger() && DstEltVT.isInteger()); 3737 if (SrcBitSize < DstBitSize) { 3738 unsigned NumInputsPerOutput = DstBitSize/SrcBitSize; 3739 3740 SmallVector<SDValue, 8> Ops; 3741 for (unsigned i = 0, e = BV->getNumOperands(); i != e; 3742 i += NumInputsPerOutput) { 3743 bool isLE = TLI.isLittleEndian(); 3744 APInt NewBits = APInt(DstBitSize, 0); 3745 bool EltIsUndef = true; 3746 for (unsigned j = 0; j != NumInputsPerOutput; ++j) { 3747 // Shift the previously computed bits over. 3748 NewBits <<= SrcBitSize; 3749 SDValue Op = BV->getOperand(i+ (isLE ? (NumInputsPerOutput-j-1) : j)); 3750 if (Op.getOpcode() == ISD::UNDEF) continue; 3751 EltIsUndef = false; 3752 3753 NewBits |= 3754 APInt(cast<ConstantSDNode>(Op)->getAPIntValue()).zext(DstBitSize); 3755 } 3756 3757 if (EltIsUndef) 3758 Ops.push_back(DAG.getNode(ISD::UNDEF, DstEltVT)); 3759 else 3760 Ops.push_back(DAG.getConstant(NewBits, DstEltVT)); 3761 } 3762 3763 MVT VT = MVT::getVectorVT(DstEltVT, Ops.size()); 3764 return DAG.getNode(ISD::BUILD_VECTOR, VT, &Ops[0], Ops.size()); 3765 } 3766 3767 // Finally, this must be the case where we are shrinking elements: each input 3768 // turns into multiple outputs. 3769 bool isS2V = ISD::isScalarToVector(BV); 3770 unsigned NumOutputsPerInput = SrcBitSize/DstBitSize; 3771 MVT VT = MVT::getVectorVT(DstEltVT, NumOutputsPerInput*BV->getNumOperands()); 3772 SmallVector<SDValue, 8> Ops; 3773 for (unsigned i = 0, e = BV->getNumOperands(); i != e; ++i) { 3774 if (BV->getOperand(i).getOpcode() == ISD::UNDEF) { 3775 for (unsigned j = 0; j != NumOutputsPerInput; ++j) 3776 Ops.push_back(DAG.getNode(ISD::UNDEF, DstEltVT)); 3777 continue; 3778 } 3779 APInt OpVal = cast<ConstantSDNode>(BV->getOperand(i))->getAPIntValue(); 3780 for (unsigned j = 0; j != NumOutputsPerInput; ++j) { 3781 APInt ThisVal = APInt(OpVal).trunc(DstBitSize); 3782 Ops.push_back(DAG.getConstant(ThisVal, DstEltVT)); 3783 if (isS2V && i == 0 && j == 0 && APInt(ThisVal).zext(SrcBitSize) == OpVal) 3784 // Simply turn this into a SCALAR_TO_VECTOR of the new type. 3785 return DAG.getNode(ISD::SCALAR_TO_VECTOR, VT, Ops[0]); 3786 OpVal = OpVal.lshr(DstBitSize); 3787 } 3788 3789 // For big endian targets, swap the order of the pieces of each element. 3790 if (TLI.isBigEndian()) 3791 std::reverse(Ops.end()-NumOutputsPerInput, Ops.end()); 3792 } 3793 return DAG.getNode(ISD::BUILD_VECTOR, VT, &Ops[0], Ops.size()); 3794} 3795 3796 3797 3798SDValue DAGCombiner::visitFADD(SDNode *N) { 3799 SDValue N0 = N->getOperand(0); 3800 SDValue N1 = N->getOperand(1); 3801 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 3802 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1); 3803 MVT VT = N->getValueType(0); 3804 3805 // fold vector ops 3806 if (VT.isVector()) { 3807 SDValue FoldedVOp = SimplifyVBinOp(N); 3808 if (FoldedVOp.getNode()) return FoldedVOp; 3809 } 3810 3811 // fold (fadd c1, c2) -> c1+c2 3812 if (N0CFP && N1CFP && VT != MVT::ppcf128) 3813 return DAG.getNode(ISD::FADD, VT, N0, N1); 3814 // canonicalize constant to RHS 3815 if (N0CFP && !N1CFP) 3816 return DAG.getNode(ISD::FADD, VT, N1, N0); 3817 // fold (A + (-B)) -> A-B 3818 if (isNegatibleForFree(N1, LegalOperations) == 2) 3819 return DAG.getNode(ISD::FSUB, VT, N0, 3820 GetNegatedExpression(N1, DAG, LegalOperations)); 3821 // fold ((-A) + B) -> B-A 3822 if (isNegatibleForFree(N0, LegalOperations) == 2) 3823 return DAG.getNode(ISD::FSUB, VT, N1, 3824 GetNegatedExpression(N0, DAG, LegalOperations)); 3825 3826 // If allowed, fold (fadd (fadd x, c1), c2) -> (fadd x, (fadd c1, c2)) 3827 if (UnsafeFPMath && N1CFP && N0.getOpcode() == ISD::FADD && 3828 N0.getNode()->hasOneUse() && isa<ConstantFPSDNode>(N0.getOperand(1))) 3829 return DAG.getNode(ISD::FADD, VT, N0.getOperand(0), 3830 DAG.getNode(ISD::FADD, VT, N0.getOperand(1), N1)); 3831 3832 return SDValue(); 3833} 3834 3835SDValue DAGCombiner::visitFSUB(SDNode *N) { 3836 SDValue N0 = N->getOperand(0); 3837 SDValue N1 = N->getOperand(1); 3838 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 3839 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1); 3840 MVT VT = N->getValueType(0); 3841 3842 // fold vector ops 3843 if (VT.isVector()) { 3844 SDValue FoldedVOp = SimplifyVBinOp(N); 3845 if (FoldedVOp.getNode()) return FoldedVOp; 3846 } 3847 3848 // fold (fsub c1, c2) -> c1-c2 3849 if (N0CFP && N1CFP && VT != MVT::ppcf128) 3850 return DAG.getNode(ISD::FSUB, VT, N0, N1); 3851 // fold (0-B) -> -B 3852 if (UnsafeFPMath && N0CFP && N0CFP->getValueAPF().isZero()) { 3853 if (isNegatibleForFree(N1, LegalOperations)) 3854 return GetNegatedExpression(N1, DAG, LegalOperations); 3855 return DAG.getNode(ISD::FNEG, VT, N1); 3856 } 3857 // fold (A-(-B)) -> A+B 3858 if (isNegatibleForFree(N1, LegalOperations)) 3859 return DAG.getNode(ISD::FADD, VT, N0, 3860 GetNegatedExpression(N1, DAG, LegalOperations)); 3861 3862 return SDValue(); 3863} 3864 3865SDValue DAGCombiner::visitFMUL(SDNode *N) { 3866 SDValue N0 = N->getOperand(0); 3867 SDValue N1 = N->getOperand(1); 3868 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 3869 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1); 3870 MVT VT = N->getValueType(0); 3871 3872 // fold vector ops 3873 if (VT.isVector()) { 3874 SDValue FoldedVOp = SimplifyVBinOp(N); 3875 if (FoldedVOp.getNode()) return FoldedVOp; 3876 } 3877 3878 // fold (fmul c1, c2) -> c1*c2 3879 if (N0CFP && N1CFP && VT != MVT::ppcf128) 3880 return DAG.getNode(ISD::FMUL, VT, N0, N1); 3881 // canonicalize constant to RHS 3882 if (N0CFP && !N1CFP) 3883 return DAG.getNode(ISD::FMUL, VT, N1, N0); 3884 // fold (fmul X, 2.0) -> (fadd X, X) 3885 if (N1CFP && N1CFP->isExactlyValue(+2.0)) 3886 return DAG.getNode(ISD::FADD, VT, N0, N0); 3887 // fold (fmul X, -1.0) -> (fneg X) 3888 if (N1CFP && N1CFP->isExactlyValue(-1.0)) 3889 return DAG.getNode(ISD::FNEG, VT, N0); 3890 3891 // -X * -Y -> X*Y 3892 if (char LHSNeg = isNegatibleForFree(N0, LegalOperations)) { 3893 if (char RHSNeg = isNegatibleForFree(N1, LegalOperations)) { 3894 // Both can be negated for free, check to see if at least one is cheaper 3895 // negated. 3896 if (LHSNeg == 2 || RHSNeg == 2) 3897 return DAG.getNode(ISD::FMUL, VT, 3898 GetNegatedExpression(N0, DAG, LegalOperations), 3899 GetNegatedExpression(N1, DAG, LegalOperations)); 3900 } 3901 } 3902 3903 // If allowed, fold (fmul (fmul x, c1), c2) -> (fmul x, (fmul c1, c2)) 3904 if (UnsafeFPMath && N1CFP && N0.getOpcode() == ISD::FMUL && 3905 N0.getNode()->hasOneUse() && isa<ConstantFPSDNode>(N0.getOperand(1))) 3906 return DAG.getNode(ISD::FMUL, VT, N0.getOperand(0), 3907 DAG.getNode(ISD::FMUL, VT, N0.getOperand(1), N1)); 3908 3909 return SDValue(); 3910} 3911 3912SDValue DAGCombiner::visitFDIV(SDNode *N) { 3913 SDValue N0 = N->getOperand(0); 3914 SDValue N1 = N->getOperand(1); 3915 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 3916 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1); 3917 MVT VT = N->getValueType(0); 3918 3919 // fold vector ops 3920 if (VT.isVector()) { 3921 SDValue FoldedVOp = SimplifyVBinOp(N); 3922 if (FoldedVOp.getNode()) return FoldedVOp; 3923 } 3924 3925 // fold (fdiv c1, c2) -> c1/c2 3926 if (N0CFP && N1CFP && VT != MVT::ppcf128) 3927 return DAG.getNode(ISD::FDIV, VT, N0, N1); 3928 3929 3930 // -X / -Y -> X*Y 3931 if (char LHSNeg = isNegatibleForFree(N0, LegalOperations)) { 3932 if (char RHSNeg = isNegatibleForFree(N1, LegalOperations)) { 3933 // Both can be negated for free, check to see if at least one is cheaper 3934 // negated. 3935 if (LHSNeg == 2 || RHSNeg == 2) 3936 return DAG.getNode(ISD::FDIV, VT, 3937 GetNegatedExpression(N0, DAG, LegalOperations), 3938 GetNegatedExpression(N1, DAG, LegalOperations)); 3939 } 3940 } 3941 3942 return SDValue(); 3943} 3944 3945SDValue DAGCombiner::visitFREM(SDNode *N) { 3946 SDValue N0 = N->getOperand(0); 3947 SDValue N1 = N->getOperand(1); 3948 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 3949 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1); 3950 MVT VT = N->getValueType(0); 3951 3952 // fold (frem c1, c2) -> fmod(c1,c2) 3953 if (N0CFP && N1CFP && VT != MVT::ppcf128) 3954 return DAG.getNode(ISD::FREM, VT, N0, N1); 3955 3956 return SDValue(); 3957} 3958 3959SDValue DAGCombiner::visitFCOPYSIGN(SDNode *N) { 3960 SDValue N0 = N->getOperand(0); 3961 SDValue N1 = N->getOperand(1); 3962 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 3963 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1); 3964 MVT VT = N->getValueType(0); 3965 3966 if (N0CFP && N1CFP && VT != MVT::ppcf128) // Constant fold 3967 return DAG.getNode(ISD::FCOPYSIGN, VT, N0, N1); 3968 3969 if (N1CFP) { 3970 const APFloat& V = N1CFP->getValueAPF(); 3971 // copysign(x, c1) -> fabs(x) iff ispos(c1) 3972 // copysign(x, c1) -> fneg(fabs(x)) iff isneg(c1) 3973 if (!V.isNegative()) 3974 return DAG.getNode(ISD::FABS, VT, N0); 3975 else 3976 return DAG.getNode(ISD::FNEG, VT, DAG.getNode(ISD::FABS, VT, N0)); 3977 } 3978 3979 // copysign(fabs(x), y) -> copysign(x, y) 3980 // copysign(fneg(x), y) -> copysign(x, y) 3981 // copysign(copysign(x,z), y) -> copysign(x, y) 3982 if (N0.getOpcode() == ISD::FABS || N0.getOpcode() == ISD::FNEG || 3983 N0.getOpcode() == ISD::FCOPYSIGN) 3984 return DAG.getNode(ISD::FCOPYSIGN, VT, N0.getOperand(0), N1); 3985 3986 // copysign(x, abs(y)) -> abs(x) 3987 if (N1.getOpcode() == ISD::FABS) 3988 return DAG.getNode(ISD::FABS, VT, N0); 3989 3990 // copysign(x, copysign(y,z)) -> copysign(x, z) 3991 if (N1.getOpcode() == ISD::FCOPYSIGN) 3992 return DAG.getNode(ISD::FCOPYSIGN, VT, N0, N1.getOperand(1)); 3993 3994 // copysign(x, fp_extend(y)) -> copysign(x, y) 3995 // copysign(x, fp_round(y)) -> copysign(x, y) 3996 if (N1.getOpcode() == ISD::FP_EXTEND || N1.getOpcode() == ISD::FP_ROUND) 3997 return DAG.getNode(ISD::FCOPYSIGN, VT, N0, N1.getOperand(0)); 3998 3999 return SDValue(); 4000} 4001 4002 4003 4004SDValue DAGCombiner::visitSINT_TO_FP(SDNode *N) { 4005 SDValue N0 = N->getOperand(0); 4006 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 4007 MVT VT = N->getValueType(0); 4008 MVT OpVT = N0.getValueType(); 4009 4010 // fold (sint_to_fp c1) -> c1fp 4011 if (N0C && OpVT != MVT::ppcf128) 4012 return DAG.getNode(ISD::SINT_TO_FP, VT, N0); 4013 4014 // If the input is a legal type, and SINT_TO_FP is not legal on this target, 4015 // but UINT_TO_FP is legal on this target, try to convert. 4016 if (!TLI.isOperationLegal(ISD::SINT_TO_FP, OpVT) && 4017 TLI.isOperationLegal(ISD::UINT_TO_FP, OpVT)) { 4018 // If the sign bit is known to be zero, we can change this to UINT_TO_FP. 4019 if (DAG.SignBitIsZero(N0)) 4020 return DAG.getNode(ISD::UINT_TO_FP, VT, N0); 4021 } 4022 4023 4024 return SDValue(); 4025} 4026 4027SDValue DAGCombiner::visitUINT_TO_FP(SDNode *N) { 4028 SDValue N0 = N->getOperand(0); 4029 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 4030 MVT VT = N->getValueType(0); 4031 MVT OpVT = N0.getValueType(); 4032 4033 // fold (uint_to_fp c1) -> c1fp 4034 if (N0C && OpVT != MVT::ppcf128) 4035 return DAG.getNode(ISD::UINT_TO_FP, VT, N0); 4036 4037 // If the input is a legal type, and UINT_TO_FP is not legal on this target, 4038 // but SINT_TO_FP is legal on this target, try to convert. 4039 if (!TLI.isOperationLegal(ISD::UINT_TO_FP, OpVT) && 4040 TLI.isOperationLegal(ISD::SINT_TO_FP, OpVT)) { 4041 // If the sign bit is known to be zero, we can change this to SINT_TO_FP. 4042 if (DAG.SignBitIsZero(N0)) 4043 return DAG.getNode(ISD::SINT_TO_FP, VT, N0); 4044 } 4045 4046 return SDValue(); 4047} 4048 4049SDValue DAGCombiner::visitFP_TO_SINT(SDNode *N) { 4050 SDValue N0 = N->getOperand(0); 4051 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 4052 MVT VT = N->getValueType(0); 4053 4054 // fold (fp_to_sint c1fp) -> c1 4055 if (N0CFP) 4056 return DAG.getNode(ISD::FP_TO_SINT, VT, N0); 4057 return SDValue(); 4058} 4059 4060SDValue DAGCombiner::visitFP_TO_UINT(SDNode *N) { 4061 SDValue N0 = N->getOperand(0); 4062 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 4063 MVT VT = N->getValueType(0); 4064 4065 // fold (fp_to_uint c1fp) -> c1 4066 if (N0CFP && VT != MVT::ppcf128) 4067 return DAG.getNode(ISD::FP_TO_UINT, VT, N0); 4068 return SDValue(); 4069} 4070 4071SDValue DAGCombiner::visitFP_ROUND(SDNode *N) { 4072 SDValue N0 = N->getOperand(0); 4073 SDValue N1 = N->getOperand(1); 4074 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 4075 MVT VT = N->getValueType(0); 4076 4077 // fold (fp_round c1fp) -> c1fp 4078 if (N0CFP && N0.getValueType() != MVT::ppcf128) 4079 return DAG.getNode(ISD::FP_ROUND, VT, N0, N1); 4080 4081 // fold (fp_round (fp_extend x)) -> x 4082 if (N0.getOpcode() == ISD::FP_EXTEND && VT == N0.getOperand(0).getValueType()) 4083 return N0.getOperand(0); 4084 4085 // fold (fp_round (fp_round x)) -> (fp_round x) 4086 if (N0.getOpcode() == ISD::FP_ROUND) { 4087 // This is a value preserving truncation if both round's are. 4088 bool IsTrunc = N->getConstantOperandVal(1) == 1 && 4089 N0.getNode()->getConstantOperandVal(1) == 1; 4090 return DAG.getNode(ISD::FP_ROUND, VT, N0.getOperand(0), 4091 DAG.getIntPtrConstant(IsTrunc)); 4092 } 4093 4094 // fold (fp_round (copysign X, Y)) -> (copysign (fp_round X), Y) 4095 if (N0.getOpcode() == ISD::FCOPYSIGN && N0.getNode()->hasOneUse()) { 4096 SDValue Tmp = DAG.getNode(ISD::FP_ROUND, VT, N0.getOperand(0), N1); 4097 AddToWorkList(Tmp.getNode()); 4098 return DAG.getNode(ISD::FCOPYSIGN, VT, Tmp, N0.getOperand(1)); 4099 } 4100 4101 return SDValue(); 4102} 4103 4104SDValue DAGCombiner::visitFP_ROUND_INREG(SDNode *N) { 4105 SDValue N0 = N->getOperand(0); 4106 MVT VT = N->getValueType(0); 4107 MVT EVT = cast<VTSDNode>(N->getOperand(1))->getVT(); 4108 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 4109 4110 // fold (fp_round_inreg c1fp) -> c1fp 4111 if (N0CFP && (TLI.isTypeLegal(EVT) || !LegalTypes)) { 4112 SDValue Round = DAG.getConstantFP(*N0CFP->getConstantFPValue(), EVT); 4113 return DAG.getNode(ISD::FP_EXTEND, VT, Round); 4114 } 4115 return SDValue(); 4116} 4117 4118SDValue DAGCombiner::visitFP_EXTEND(SDNode *N) { 4119 SDValue N0 = N->getOperand(0); 4120 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 4121 MVT VT = N->getValueType(0); 4122 4123 // If this is fp_round(fpextend), don't fold it, allow ourselves to be folded. 4124 if (N->hasOneUse() && 4125 N->use_begin().getUse().getSDValue().getOpcode() == ISD::FP_ROUND) 4126 return SDValue(); 4127 4128 // fold (fp_extend c1fp) -> c1fp 4129 if (N0CFP && VT != MVT::ppcf128) 4130 return DAG.getNode(ISD::FP_EXTEND, VT, N0); 4131 4132 // Turn fp_extend(fp_round(X, 1)) -> x since the fp_round doesn't affect the 4133 // value of X. 4134 if (N0.getOpcode() == ISD::FP_ROUND 4135 && N0.getNode()->getConstantOperandVal(1) == 1) { 4136 SDValue In = N0.getOperand(0); 4137 if (In.getValueType() == VT) return In; 4138 if (VT.bitsLT(In.getValueType())) 4139 return DAG.getNode(ISD::FP_ROUND, VT, In, N0.getOperand(1)); 4140 return DAG.getNode(ISD::FP_EXTEND, VT, In); 4141 } 4142 4143 // fold (fpext (load x)) -> (fpext (fptrunc (extload x))) 4144 if (ISD::isNON_EXTLoad(N0.getNode()) && N0.hasOneUse() && 4145 ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) || 4146 TLI.isLoadExtLegal(ISD::EXTLOAD, N0.getValueType()))) { 4147 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 4148 SDValue ExtLoad = DAG.getExtLoad(ISD::EXTLOAD, VT, LN0->getChain(), 4149 LN0->getBasePtr(), LN0->getSrcValue(), 4150 LN0->getSrcValueOffset(), 4151 N0.getValueType(), 4152 LN0->isVolatile(), LN0->getAlignment()); 4153 CombineTo(N, ExtLoad); 4154 CombineTo(N0.getNode(), DAG.getNode(ISD::FP_ROUND, N0.getValueType(), 4155 ExtLoad, DAG.getIntPtrConstant(1)), 4156 ExtLoad.getValue(1)); 4157 return SDValue(N, 0); // Return N so it doesn't get rechecked! 4158 } 4159 4160 return SDValue(); 4161} 4162 4163SDValue DAGCombiner::visitFNEG(SDNode *N) { 4164 SDValue N0 = N->getOperand(0); 4165 4166 if (isNegatibleForFree(N0, LegalOperations)) 4167 return GetNegatedExpression(N0, DAG, LegalOperations); 4168 4169 // Transform fneg(bitconvert(x)) -> bitconvert(x^sign) to avoid loading 4170 // constant pool values. 4171 if (N0.getOpcode() == ISD::BIT_CONVERT && N0.getNode()->hasOneUse() && 4172 N0.getOperand(0).getValueType().isInteger() && 4173 !N0.getOperand(0).getValueType().isVector()) { 4174 SDValue Int = N0.getOperand(0); 4175 MVT IntVT = Int.getValueType(); 4176 if (IntVT.isInteger() && !IntVT.isVector()) { 4177 Int = DAG.getNode(ISD::XOR, IntVT, Int, 4178 DAG.getConstant(IntVT.getIntegerVTSignBit(), IntVT)); 4179 AddToWorkList(Int.getNode()); 4180 return DAG.getNode(ISD::BIT_CONVERT, N->getValueType(0), Int); 4181 } 4182 } 4183 4184 return SDValue(); 4185} 4186 4187SDValue DAGCombiner::visitFABS(SDNode *N) { 4188 SDValue N0 = N->getOperand(0); 4189 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 4190 MVT VT = N->getValueType(0); 4191 4192 // fold (fabs c1) -> fabs(c1) 4193 if (N0CFP && VT != MVT::ppcf128) 4194 return DAG.getNode(ISD::FABS, VT, N0); 4195 // fold (fabs (fabs x)) -> (fabs x) 4196 if (N0.getOpcode() == ISD::FABS) 4197 return N->getOperand(0); 4198 // fold (fabs (fneg x)) -> (fabs x) 4199 // fold (fabs (fcopysign x, y)) -> (fabs x) 4200 if (N0.getOpcode() == ISD::FNEG || N0.getOpcode() == ISD::FCOPYSIGN) 4201 return DAG.getNode(ISD::FABS, VT, N0.getOperand(0)); 4202 4203 // Transform fabs(bitconvert(x)) -> bitconvert(x&~sign) to avoid loading 4204 // constant pool values. 4205 if (N0.getOpcode() == ISD::BIT_CONVERT && N0.getNode()->hasOneUse() && 4206 N0.getOperand(0).getValueType().isInteger() && 4207 !N0.getOperand(0).getValueType().isVector()) { 4208 SDValue Int = N0.getOperand(0); 4209 MVT IntVT = Int.getValueType(); 4210 if (IntVT.isInteger() && !IntVT.isVector()) { 4211 Int = DAG.getNode(ISD::AND, IntVT, Int, 4212 DAG.getConstant(~IntVT.getIntegerVTSignBit(), IntVT)); 4213 AddToWorkList(Int.getNode()); 4214 return DAG.getNode(ISD::BIT_CONVERT, N->getValueType(0), Int); 4215 } 4216 } 4217 4218 return SDValue(); 4219} 4220 4221SDValue DAGCombiner::visitBRCOND(SDNode *N) { 4222 SDValue Chain = N->getOperand(0); 4223 SDValue N1 = N->getOperand(1); 4224 SDValue N2 = N->getOperand(2); 4225 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 4226 4227 // never taken branch, fold to chain 4228 if (N1C && N1C->isNullValue()) 4229 return Chain; 4230 // unconditional branch 4231 if (N1C && N1C->getAPIntValue() == 1) 4232 return DAG.getNode(ISD::BR, MVT::Other, Chain, N2); 4233 // fold a brcond with a setcc condition into a BR_CC node if BR_CC is legal 4234 // on the target. 4235 if (N1.getOpcode() == ISD::SETCC && 4236 TLI.isOperationLegal(ISD::BR_CC, MVT::Other)) { 4237 return DAG.getNode(ISD::BR_CC, MVT::Other, Chain, N1.getOperand(2), 4238 N1.getOperand(0), N1.getOperand(1), N2); 4239 } 4240 return SDValue(); 4241} 4242 4243// Operand List for BR_CC: Chain, CondCC, CondLHS, CondRHS, DestBB. 4244// 4245SDValue DAGCombiner::visitBR_CC(SDNode *N) { 4246 CondCodeSDNode *CC = cast<CondCodeSDNode>(N->getOperand(1)); 4247 SDValue CondLHS = N->getOperand(2), CondRHS = N->getOperand(3); 4248 4249 // Use SimplifySetCC to simplify SETCC's. 4250 SDValue Simp = SimplifySetCC(TLI.getSetCCResultType(CondLHS.getValueType()), 4251 CondLHS, CondRHS, CC->get(), false); 4252 if (Simp.getNode()) AddToWorkList(Simp.getNode()); 4253 4254 ConstantSDNode *SCCC = dyn_cast_or_null<ConstantSDNode>(Simp.getNode()); 4255 4256 // fold br_cc true, dest -> br dest (unconditional branch) 4257 if (SCCC && !SCCC->isNullValue()) 4258 return DAG.getNode(ISD::BR, MVT::Other, N->getOperand(0), 4259 N->getOperand(4)); 4260 // fold br_cc false, dest -> unconditional fall through 4261 if (SCCC && SCCC->isNullValue()) 4262 return N->getOperand(0); 4263 4264 // fold to a simpler setcc 4265 if (Simp.getNode() && Simp.getOpcode() == ISD::SETCC) 4266 return DAG.getNode(ISD::BR_CC, MVT::Other, N->getOperand(0), 4267 Simp.getOperand(2), Simp.getOperand(0), 4268 Simp.getOperand(1), N->getOperand(4)); 4269 return SDValue(); 4270} 4271 4272 4273/// CombineToPreIndexedLoadStore - Try turning a load / store into a 4274/// pre-indexed load / store when the base pointer is an add or subtract 4275/// and it has other uses besides the load / store. After the 4276/// transformation, the new indexed load / store has effectively folded 4277/// the add / subtract in and all of its other uses are redirected to the 4278/// new load / store. 4279bool DAGCombiner::CombineToPreIndexedLoadStore(SDNode *N) { 4280 if (!LegalOperations) 4281 return false; 4282 4283 bool isLoad = true; 4284 SDValue Ptr; 4285 MVT VT; 4286 if (LoadSDNode *LD = dyn_cast<LoadSDNode>(N)) { 4287 if (LD->isIndexed()) 4288 return false; 4289 VT = LD->getMemoryVT(); 4290 if (!TLI.isIndexedLoadLegal(ISD::PRE_INC, VT) && 4291 !TLI.isIndexedLoadLegal(ISD::PRE_DEC, VT)) 4292 return false; 4293 Ptr = LD->getBasePtr(); 4294 } else if (StoreSDNode *ST = dyn_cast<StoreSDNode>(N)) { 4295 if (ST->isIndexed()) 4296 return false; 4297 VT = ST->getMemoryVT(); 4298 if (!TLI.isIndexedStoreLegal(ISD::PRE_INC, VT) && 4299 !TLI.isIndexedStoreLegal(ISD::PRE_DEC, VT)) 4300 return false; 4301 Ptr = ST->getBasePtr(); 4302 isLoad = false; 4303 } else 4304 return false; 4305 4306 // If the pointer is not an add/sub, or if it doesn't have multiple uses, bail 4307 // out. There is no reason to make this a preinc/predec. 4308 if ((Ptr.getOpcode() != ISD::ADD && Ptr.getOpcode() != ISD::SUB) || 4309 Ptr.getNode()->hasOneUse()) 4310 return false; 4311 4312 // Ask the target to do addressing mode selection. 4313 SDValue BasePtr; 4314 SDValue Offset; 4315 ISD::MemIndexedMode AM = ISD::UNINDEXED; 4316 if (!TLI.getPreIndexedAddressParts(N, BasePtr, Offset, AM, DAG)) 4317 return false; 4318 // Don't create a indexed load / store with zero offset. 4319 if (isa<ConstantSDNode>(Offset) && 4320 cast<ConstantSDNode>(Offset)->isNullValue()) 4321 return false; 4322 4323 // Try turning it into a pre-indexed load / store except when: 4324 // 1) The new base ptr is a frame index. 4325 // 2) If N is a store and the new base ptr is either the same as or is a 4326 // predecessor of the value being stored. 4327 // 3) Another use of old base ptr is a predecessor of N. If ptr is folded 4328 // that would create a cycle. 4329 // 4) All uses are load / store ops that use it as old base ptr. 4330 4331 // Check #1. Preinc'ing a frame index would require copying the stack pointer 4332 // (plus the implicit offset) to a register to preinc anyway. 4333 if (isa<FrameIndexSDNode>(BasePtr)) 4334 return false; 4335 4336 // Check #2. 4337 if (!isLoad) { 4338 SDValue Val = cast<StoreSDNode>(N)->getValue(); 4339 if (Val == BasePtr || BasePtr.getNode()->isPredecessorOf(Val.getNode())) 4340 return false; 4341 } 4342 4343 // Now check for #3 and #4. 4344 bool RealUse = false; 4345 for (SDNode::use_iterator I = Ptr.getNode()->use_begin(), 4346 E = Ptr.getNode()->use_end(); I != E; ++I) { 4347 SDNode *Use = *I; 4348 if (Use == N) 4349 continue; 4350 if (Use->isPredecessorOf(N)) 4351 return false; 4352 4353 if (!((Use->getOpcode() == ISD::LOAD && 4354 cast<LoadSDNode>(Use)->getBasePtr() == Ptr) || 4355 (Use->getOpcode() == ISD::STORE && 4356 cast<StoreSDNode>(Use)->getBasePtr() == Ptr))) 4357 RealUse = true; 4358 } 4359 if (!RealUse) 4360 return false; 4361 4362 SDValue Result; 4363 if (isLoad) 4364 Result = DAG.getIndexedLoad(SDValue(N,0), BasePtr, Offset, AM); 4365 else 4366 Result = DAG.getIndexedStore(SDValue(N,0), BasePtr, Offset, AM); 4367 ++PreIndexedNodes; 4368 ++NodesCombined; 4369 DOUT << "\nReplacing.4 "; DEBUG(N->dump(&DAG)); 4370 DOUT << "\nWith: "; DEBUG(Result.getNode()->dump(&DAG)); 4371 DOUT << '\n'; 4372 WorkListRemover DeadNodes(*this); 4373 if (isLoad) { 4374 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Result.getValue(0), 4375 &DeadNodes); 4376 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), Result.getValue(2), 4377 &DeadNodes); 4378 } else { 4379 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Result.getValue(1), 4380 &DeadNodes); 4381 } 4382 4383 // Finally, since the node is now dead, remove it from the graph. 4384 DAG.DeleteNode(N); 4385 4386 // Replace the uses of Ptr with uses of the updated base value. 4387 DAG.ReplaceAllUsesOfValueWith(Ptr, Result.getValue(isLoad ? 1 : 0), 4388 &DeadNodes); 4389 removeFromWorkList(Ptr.getNode()); 4390 DAG.DeleteNode(Ptr.getNode()); 4391 4392 return true; 4393} 4394 4395/// CombineToPostIndexedLoadStore - Try to combine a load / store with a 4396/// add / sub of the base pointer node into a post-indexed load / store. 4397/// The transformation folded the add / subtract into the new indexed 4398/// load / store effectively and all of its uses are redirected to the 4399/// new load / store. 4400bool DAGCombiner::CombineToPostIndexedLoadStore(SDNode *N) { 4401 if (!LegalOperations) 4402 return false; 4403 4404 bool isLoad = true; 4405 SDValue Ptr; 4406 MVT VT; 4407 if (LoadSDNode *LD = dyn_cast<LoadSDNode>(N)) { 4408 if (LD->isIndexed()) 4409 return false; 4410 VT = LD->getMemoryVT(); 4411 if (!TLI.isIndexedLoadLegal(ISD::POST_INC, VT) && 4412 !TLI.isIndexedLoadLegal(ISD::POST_DEC, VT)) 4413 return false; 4414 Ptr = LD->getBasePtr(); 4415 } else if (StoreSDNode *ST = dyn_cast<StoreSDNode>(N)) { 4416 if (ST->isIndexed()) 4417 return false; 4418 VT = ST->getMemoryVT(); 4419 if (!TLI.isIndexedStoreLegal(ISD::POST_INC, VT) && 4420 !TLI.isIndexedStoreLegal(ISD::POST_DEC, VT)) 4421 return false; 4422 Ptr = ST->getBasePtr(); 4423 isLoad = false; 4424 } else 4425 return false; 4426 4427 if (Ptr.getNode()->hasOneUse()) 4428 return false; 4429 4430 for (SDNode::use_iterator I = Ptr.getNode()->use_begin(), 4431 E = Ptr.getNode()->use_end(); I != E; ++I) { 4432 SDNode *Op = *I; 4433 if (Op == N || 4434 (Op->getOpcode() != ISD::ADD && Op->getOpcode() != ISD::SUB)) 4435 continue; 4436 4437 SDValue BasePtr; 4438 SDValue Offset; 4439 ISD::MemIndexedMode AM = ISD::UNINDEXED; 4440 if (TLI.getPostIndexedAddressParts(N, Op, BasePtr, Offset, AM, DAG)) { 4441 if (Ptr == Offset) 4442 std::swap(BasePtr, Offset); 4443 if (Ptr != BasePtr) 4444 continue; 4445 // Don't create a indexed load / store with zero offset. 4446 if (isa<ConstantSDNode>(Offset) && 4447 cast<ConstantSDNode>(Offset)->isNullValue()) 4448 continue; 4449 4450 // Try turning it into a post-indexed load / store except when 4451 // 1) All uses are load / store ops that use it as base ptr. 4452 // 2) Op must be independent of N, i.e. Op is neither a predecessor 4453 // nor a successor of N. Otherwise, if Op is folded that would 4454 // create a cycle. 4455 4456 // Check for #1. 4457 bool TryNext = false; 4458 for (SDNode::use_iterator II = BasePtr.getNode()->use_begin(), 4459 EE = BasePtr.getNode()->use_end(); II != EE; ++II) { 4460 SDNode *Use = *II; 4461 if (Use == Ptr.getNode()) 4462 continue; 4463 4464 // If all the uses are load / store addresses, then don't do the 4465 // transformation. 4466 if (Use->getOpcode() == ISD::ADD || Use->getOpcode() == ISD::SUB){ 4467 bool RealUse = false; 4468 for (SDNode::use_iterator III = Use->use_begin(), 4469 EEE = Use->use_end(); III != EEE; ++III) { 4470 SDNode *UseUse = *III; 4471 if (!((UseUse->getOpcode() == ISD::LOAD && 4472 cast<LoadSDNode>(UseUse)->getBasePtr().getNode() == Use) || 4473 (UseUse->getOpcode() == ISD::STORE && 4474 cast<StoreSDNode>(UseUse)->getBasePtr().getNode() == Use))) 4475 RealUse = true; 4476 } 4477 4478 if (!RealUse) { 4479 TryNext = true; 4480 break; 4481 } 4482 } 4483 } 4484 if (TryNext) 4485 continue; 4486 4487 // Check for #2 4488 if (!Op->isPredecessorOf(N) && !N->isPredecessorOf(Op)) { 4489 SDValue Result = isLoad 4490 ? DAG.getIndexedLoad(SDValue(N,0), BasePtr, Offset, AM) 4491 : DAG.getIndexedStore(SDValue(N,0), BasePtr, Offset, AM); 4492 ++PostIndexedNodes; 4493 ++NodesCombined; 4494 DOUT << "\nReplacing.5 "; DEBUG(N->dump(&DAG)); 4495 DOUT << "\nWith: "; DEBUG(Result.getNode()->dump(&DAG)); 4496 DOUT << '\n'; 4497 WorkListRemover DeadNodes(*this); 4498 if (isLoad) { 4499 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Result.getValue(0), 4500 &DeadNodes); 4501 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), Result.getValue(2), 4502 &DeadNodes); 4503 } else { 4504 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Result.getValue(1), 4505 &DeadNodes); 4506 } 4507 4508 // Finally, since the node is now dead, remove it from the graph. 4509 DAG.DeleteNode(N); 4510 4511 // Replace the uses of Use with uses of the updated base value. 4512 DAG.ReplaceAllUsesOfValueWith(SDValue(Op, 0), 4513 Result.getValue(isLoad ? 1 : 0), 4514 &DeadNodes); 4515 removeFromWorkList(Op); 4516 DAG.DeleteNode(Op); 4517 return true; 4518 } 4519 } 4520 } 4521 return false; 4522} 4523 4524/// InferAlignment - If we can infer some alignment information from this 4525/// pointer, return it. 4526static unsigned InferAlignment(SDValue Ptr, SelectionDAG &DAG) { 4527 // If this is a direct reference to a stack slot, use information about the 4528 // stack slot's alignment. 4529 int FrameIdx = 1 << 31; 4530 int64_t FrameOffset = 0; 4531 if (FrameIndexSDNode *FI = dyn_cast<FrameIndexSDNode>(Ptr)) { 4532 FrameIdx = FI->getIndex(); 4533 } else if (Ptr.getOpcode() == ISD::ADD && 4534 isa<ConstantSDNode>(Ptr.getOperand(1)) && 4535 isa<FrameIndexSDNode>(Ptr.getOperand(0))) { 4536 FrameIdx = cast<FrameIndexSDNode>(Ptr.getOperand(0))->getIndex(); 4537 FrameOffset = Ptr.getConstantOperandVal(1); 4538 } 4539 4540 if (FrameIdx != (1 << 31)) { 4541 // FIXME: Handle FI+CST. 4542 const MachineFrameInfo &MFI = *DAG.getMachineFunction().getFrameInfo(); 4543 if (MFI.isFixedObjectIndex(FrameIdx)) { 4544 int64_t ObjectOffset = MFI.getObjectOffset(FrameIdx) + FrameOffset; 4545 4546 // The alignment of the frame index can be determined from its offset from 4547 // the incoming frame position. If the frame object is at offset 32 and 4548 // the stack is guaranteed to be 16-byte aligned, then we know that the 4549 // object is 16-byte aligned. 4550 unsigned StackAlign = DAG.getTarget().getFrameInfo()->getStackAlignment(); 4551 unsigned Align = MinAlign(ObjectOffset, StackAlign); 4552 4553 // Finally, the frame object itself may have a known alignment. Factor 4554 // the alignment + offset into a new alignment. For example, if we know 4555 // the FI is 8 byte aligned, but the pointer is 4 off, we really have a 4556 // 4-byte alignment of the resultant pointer. Likewise align 4 + 4-byte 4557 // offset = 4-byte alignment, align 4 + 1-byte offset = align 1, etc. 4558 unsigned FIInfoAlign = MinAlign(MFI.getObjectAlignment(FrameIdx), 4559 FrameOffset); 4560 return std::max(Align, FIInfoAlign); 4561 } 4562 } 4563 4564 return 0; 4565} 4566 4567SDValue DAGCombiner::visitLOAD(SDNode *N) { 4568 LoadSDNode *LD = cast<LoadSDNode>(N); 4569 SDValue Chain = LD->getChain(); 4570 SDValue Ptr = LD->getBasePtr(); 4571 4572 // Try to infer better alignment information than the load already has. 4573 if (!Fast && LD->isUnindexed()) { 4574 if (unsigned Align = InferAlignment(Ptr, DAG)) { 4575 if (Align > LD->getAlignment()) 4576 return DAG.getExtLoad(LD->getExtensionType(), LD->getValueType(0), 4577 Chain, Ptr, LD->getSrcValue(), 4578 LD->getSrcValueOffset(), LD->getMemoryVT(), 4579 LD->isVolatile(), Align); 4580 } 4581 } 4582 4583 4584 // If load is not volatile and there are no uses of the loaded value (and 4585 // the updated indexed value in case of indexed loads), change uses of the 4586 // chain value into uses of the chain input (i.e. delete the dead load). 4587 if (!LD->isVolatile()) { 4588 if (N->getValueType(1) == MVT::Other) { 4589 // Unindexed loads. 4590 if (N->hasNUsesOfValue(0, 0)) { 4591 // It's not safe to use the two value CombineTo variant here. e.g. 4592 // v1, chain2 = load chain1, loc 4593 // v2, chain3 = load chain2, loc 4594 // v3 = add v2, c 4595 // Now we replace use of chain2 with chain1. This makes the second load 4596 // isomorphic to the one we are deleting, and thus makes this load live. 4597 DOUT << "\nReplacing.6 "; DEBUG(N->dump(&DAG)); 4598 DOUT << "\nWith chain: "; DEBUG(Chain.getNode()->dump(&DAG)); 4599 DOUT << "\n"; 4600 WorkListRemover DeadNodes(*this); 4601 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), Chain, &DeadNodes); 4602 if (N->use_empty()) { 4603 removeFromWorkList(N); 4604 DAG.DeleteNode(N); 4605 } 4606 return SDValue(N, 0); // Return N so it doesn't get rechecked! 4607 } 4608 } else { 4609 // Indexed loads. 4610 assert(N->getValueType(2) == MVT::Other && "Malformed indexed loads?"); 4611 if (N->hasNUsesOfValue(0, 0) && N->hasNUsesOfValue(0, 1)) { 4612 SDValue Undef = DAG.getNode(ISD::UNDEF, N->getValueType(0)); 4613 DOUT << "\nReplacing.6 "; DEBUG(N->dump(&DAG)); 4614 DOUT << "\nWith: "; DEBUG(Undef.getNode()->dump(&DAG)); 4615 DOUT << " and 2 other values\n"; 4616 WorkListRemover DeadNodes(*this); 4617 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Undef, &DeadNodes); 4618 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), 4619 DAG.getNode(ISD::UNDEF, N->getValueType(1)), 4620 &DeadNodes); 4621 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 2), Chain, &DeadNodes); 4622 removeFromWorkList(N); 4623 DAG.DeleteNode(N); 4624 return SDValue(N, 0); // Return N so it doesn't get rechecked! 4625 } 4626 } 4627 } 4628 4629 // If this load is directly stored, replace the load value with the stored 4630 // value. 4631 // TODO: Handle store large -> read small portion. 4632 // TODO: Handle TRUNCSTORE/LOADEXT 4633 if (LD->getExtensionType() == ISD::NON_EXTLOAD && 4634 !LD->isVolatile()) { 4635 if (ISD::isNON_TRUNCStore(Chain.getNode())) { 4636 StoreSDNode *PrevST = cast<StoreSDNode>(Chain); 4637 if (PrevST->getBasePtr() == Ptr && 4638 PrevST->getValue().getValueType() == N->getValueType(0)) 4639 return CombineTo(N, Chain.getOperand(1), Chain); 4640 } 4641 } 4642 4643 if (CombinerAA) { 4644 // Walk up chain skipping non-aliasing memory nodes. 4645 SDValue BetterChain = FindBetterChain(N, Chain); 4646 4647 // If there is a better chain. 4648 if (Chain != BetterChain) { 4649 SDValue ReplLoad; 4650 4651 // Replace the chain to void dependency. 4652 if (LD->getExtensionType() == ISD::NON_EXTLOAD) { 4653 ReplLoad = DAG.getLoad(N->getValueType(0), BetterChain, Ptr, 4654 LD->getSrcValue(), LD->getSrcValueOffset(), 4655 LD->isVolatile(), LD->getAlignment()); 4656 } else { 4657 ReplLoad = DAG.getExtLoad(LD->getExtensionType(), 4658 LD->getValueType(0), 4659 BetterChain, Ptr, LD->getSrcValue(), 4660 LD->getSrcValueOffset(), 4661 LD->getMemoryVT(), 4662 LD->isVolatile(), 4663 LD->getAlignment()); 4664 } 4665 4666 // Create token factor to keep old chain connected. 4667 SDValue Token = DAG.getNode(ISD::TokenFactor, MVT::Other, 4668 Chain, ReplLoad.getValue(1)); 4669 4670 // Replace uses with load result and token factor. Don't add users 4671 // to work list. 4672 return CombineTo(N, ReplLoad.getValue(0), Token, false); 4673 } 4674 } 4675 4676 // Try transforming N to an indexed load. 4677 if (CombineToPreIndexedLoadStore(N) || CombineToPostIndexedLoadStore(N)) 4678 return SDValue(N, 0); 4679 4680 return SDValue(); 4681} 4682 4683 4684SDValue DAGCombiner::visitSTORE(SDNode *N) { 4685 StoreSDNode *ST = cast<StoreSDNode>(N); 4686 SDValue Chain = ST->getChain(); 4687 SDValue Value = ST->getValue(); 4688 SDValue Ptr = ST->getBasePtr(); 4689 4690 // Try to infer better alignment information than the store already has. 4691 if (!Fast && ST->isUnindexed()) { 4692 if (unsigned Align = InferAlignment(Ptr, DAG)) { 4693 if (Align > ST->getAlignment()) 4694 return DAG.getTruncStore(Chain, Value, Ptr, ST->getSrcValue(), 4695 ST->getSrcValueOffset(), ST->getMemoryVT(), 4696 ST->isVolatile(), Align); 4697 } 4698 } 4699 4700 // If this is a store of a bit convert, store the input value if the 4701 // resultant store does not need a higher alignment than the original. 4702 if (Value.getOpcode() == ISD::BIT_CONVERT && !ST->isTruncatingStore() && 4703 ST->isUnindexed()) { 4704 unsigned Align = ST->getAlignment(); 4705 MVT SVT = Value.getOperand(0).getValueType(); 4706 unsigned OrigAlign = TLI.getTargetData()-> 4707 getABITypeAlignment(SVT.getTypeForMVT()); 4708 if (Align <= OrigAlign && 4709 ((!LegalOperations && !ST->isVolatile()) || 4710 TLI.isOperationLegal(ISD::STORE, SVT))) 4711 return DAG.getStore(Chain, Value.getOperand(0), Ptr, ST->getSrcValue(), 4712 ST->getSrcValueOffset(), ST->isVolatile(), OrigAlign); 4713 } 4714 4715 // Turn 'store float 1.0, Ptr' -> 'store int 0x12345678, Ptr' 4716 if (ConstantFPSDNode *CFP = dyn_cast<ConstantFPSDNode>(Value)) { 4717 // NOTE: If the original store is volatile, this transform must not increase 4718 // the number of stores. For example, on x86-32 an f64 can be stored in one 4719 // processor operation but an i64 (which is not legal) requires two. So the 4720 // transform should not be done in this case. 4721 if (Value.getOpcode() != ISD::TargetConstantFP) { 4722 SDValue Tmp; 4723 switch (CFP->getValueType(0).getSimpleVT()) { 4724 default: assert(0 && "Unknown FP type"); 4725 case MVT::f80: // We don't do this for these yet. 4726 case MVT::f128: 4727 case MVT::ppcf128: 4728 break; 4729 case MVT::f32: 4730 if (((TLI.isTypeLegal(MVT::i32) || !LegalTypes) && !LegalOperations && 4731 !ST->isVolatile()) || TLI.isOperationLegal(ISD::STORE, MVT::i32)) { 4732 Tmp = DAG.getConstant((uint32_t)CFP->getValueAPF(). 4733 bitcastToAPInt().getZExtValue(), MVT::i32); 4734 return DAG.getStore(Chain, Tmp, Ptr, ST->getSrcValue(), 4735 ST->getSrcValueOffset(), ST->isVolatile(), 4736 ST->getAlignment()); 4737 } 4738 break; 4739 case MVT::f64: 4740 if (((TLI.isTypeLegal(MVT::i64) || !LegalTypes) && !LegalOperations && 4741 !ST->isVolatile()) || TLI.isOperationLegal(ISD::STORE, MVT::i64)) { 4742 Tmp = DAG.getConstant(CFP->getValueAPF().bitcastToAPInt(). 4743 getZExtValue(), MVT::i64); 4744 return DAG.getStore(Chain, Tmp, Ptr, ST->getSrcValue(), 4745 ST->getSrcValueOffset(), ST->isVolatile(), 4746 ST->getAlignment()); 4747 } else if (!ST->isVolatile() && 4748 TLI.isOperationLegal(ISD::STORE, MVT::i32)) { 4749 // Many FP stores are not made apparent until after legalize, e.g. for 4750 // argument passing. Since this is so common, custom legalize the 4751 // 64-bit integer store into two 32-bit stores. 4752 uint64_t Val = CFP->getValueAPF().bitcastToAPInt().getZExtValue(); 4753 SDValue Lo = DAG.getConstant(Val & 0xFFFFFFFF, MVT::i32); 4754 SDValue Hi = DAG.getConstant(Val >> 32, MVT::i32); 4755 if (TLI.isBigEndian()) std::swap(Lo, Hi); 4756 4757 int SVOffset = ST->getSrcValueOffset(); 4758 unsigned Alignment = ST->getAlignment(); 4759 bool isVolatile = ST->isVolatile(); 4760 4761 SDValue St0 = DAG.getStore(Chain, Lo, Ptr, ST->getSrcValue(), 4762 ST->getSrcValueOffset(), 4763 isVolatile, ST->getAlignment()); 4764 Ptr = DAG.getNode(ISD::ADD, Ptr.getValueType(), Ptr, 4765 DAG.getConstant(4, Ptr.getValueType())); 4766 SVOffset += 4; 4767 Alignment = MinAlign(Alignment, 4U); 4768 SDValue St1 = DAG.getStore(Chain, Hi, Ptr, ST->getSrcValue(), 4769 SVOffset, isVolatile, Alignment); 4770 return DAG.getNode(ISD::TokenFactor, MVT::Other, St0, St1); 4771 } 4772 break; 4773 } 4774 } 4775 } 4776 4777 if (CombinerAA) { 4778 // Walk up chain skipping non-aliasing memory nodes. 4779 SDValue BetterChain = FindBetterChain(N, Chain); 4780 4781 // If there is a better chain. 4782 if (Chain != BetterChain) { 4783 // Replace the chain to avoid dependency. 4784 SDValue ReplStore; 4785 if (ST->isTruncatingStore()) { 4786 ReplStore = DAG.getTruncStore(BetterChain, Value, Ptr, 4787 ST->getSrcValue(),ST->getSrcValueOffset(), 4788 ST->getMemoryVT(), 4789 ST->isVolatile(), ST->getAlignment()); 4790 } else { 4791 ReplStore = DAG.getStore(BetterChain, Value, Ptr, 4792 ST->getSrcValue(), ST->getSrcValueOffset(), 4793 ST->isVolatile(), ST->getAlignment()); 4794 } 4795 4796 // Create token to keep both nodes around. 4797 SDValue Token = 4798 DAG.getNode(ISD::TokenFactor, MVT::Other, Chain, ReplStore); 4799 4800 // Don't add users to work list. 4801 return CombineTo(N, Token, false); 4802 } 4803 } 4804 4805 // Try transforming N to an indexed store. 4806 if (CombineToPreIndexedLoadStore(N) || CombineToPostIndexedLoadStore(N)) 4807 return SDValue(N, 0); 4808 4809 // FIXME: is there such a thing as a truncating indexed store? 4810 if (ST->isTruncatingStore() && ST->isUnindexed() && 4811 Value.getValueType().isInteger()) { 4812 // See if we can simplify the input to this truncstore with knowledge that 4813 // only the low bits are being used. For example: 4814 // "truncstore (or (shl x, 8), y), i8" -> "truncstore y, i8" 4815 SDValue Shorter = 4816 GetDemandedBits(Value, 4817 APInt::getLowBitsSet(Value.getValueSizeInBits(), 4818 ST->getMemoryVT().getSizeInBits())); 4819 AddToWorkList(Value.getNode()); 4820 if (Shorter.getNode()) 4821 return DAG.getTruncStore(Chain, Shorter, Ptr, ST->getSrcValue(), 4822 ST->getSrcValueOffset(), ST->getMemoryVT(), 4823 ST->isVolatile(), ST->getAlignment()); 4824 4825 // Otherwise, see if we can simplify the operation with 4826 // SimplifyDemandedBits, which only works if the value has a single use. 4827 if (SimplifyDemandedBits(Value, 4828 APInt::getLowBitsSet( 4829 Value.getValueSizeInBits(), 4830 ST->getMemoryVT().getSizeInBits()))) 4831 return SDValue(N, 0); 4832 } 4833 4834 // If this is a load followed by a store to the same location, then the store 4835 // is dead/noop. 4836 if (LoadSDNode *Ld = dyn_cast<LoadSDNode>(Value)) { 4837 if (Ld->getBasePtr() == Ptr && ST->getMemoryVT() == Ld->getMemoryVT() && 4838 ST->isUnindexed() && !ST->isVolatile() && 4839 // There can't be any side effects between the load and store, such as 4840 // a call or store. 4841 Chain.reachesChainWithoutSideEffects(SDValue(Ld, 1))) { 4842 // The store is dead, remove it. 4843 return Chain; 4844 } 4845 } 4846 4847 // If this is an FP_ROUND or TRUNC followed by a store, fold this into a 4848 // truncating store. We can do this even if this is already a truncstore. 4849 if ((Value.getOpcode() == ISD::FP_ROUND || Value.getOpcode() == ISD::TRUNCATE) 4850 && Value.getNode()->hasOneUse() && ST->isUnindexed() && 4851 TLI.isTruncStoreLegal(Value.getOperand(0).getValueType(), 4852 ST->getMemoryVT())) { 4853 return DAG.getTruncStore(Chain, Value.getOperand(0), Ptr, ST->getSrcValue(), 4854 ST->getSrcValueOffset(), ST->getMemoryVT(), 4855 ST->isVolatile(), ST->getAlignment()); 4856 } 4857 4858 return SDValue(); 4859} 4860 4861SDValue DAGCombiner::visitINSERT_VECTOR_ELT(SDNode *N) { 4862 SDValue InVec = N->getOperand(0); 4863 SDValue InVal = N->getOperand(1); 4864 SDValue EltNo = N->getOperand(2); 4865 4866 // If the invec is a BUILD_VECTOR and if EltNo is a constant, build a new 4867 // vector with the inserted element. 4868 if (InVec.getOpcode() == ISD::BUILD_VECTOR && isa<ConstantSDNode>(EltNo)) { 4869 unsigned Elt = cast<ConstantSDNode>(EltNo)->getZExtValue(); 4870 SmallVector<SDValue, 8> Ops(InVec.getNode()->op_begin(), 4871 InVec.getNode()->op_end()); 4872 if (Elt < Ops.size()) 4873 Ops[Elt] = InVal; 4874 return DAG.getNode(ISD::BUILD_VECTOR, InVec.getValueType(), 4875 &Ops[0], Ops.size()); 4876 } 4877 4878 return SDValue(); 4879} 4880 4881SDValue DAGCombiner::visitEXTRACT_VECTOR_ELT(SDNode *N) { 4882 // (vextract (scalar_to_vector val, 0) -> val 4883 SDValue InVec = N->getOperand(0); 4884 4885 if (InVec.getOpcode() == ISD::SCALAR_TO_VECTOR) 4886 return InVec.getOperand(0); 4887 4888 // Perform only after legalization to ensure build_vector / vector_shuffle 4889 // optimizations have already been done. 4890 if (!LegalOperations) return SDValue(); 4891 4892 // (vextract (v4f32 load $addr), c) -> (f32 load $addr+c*size) 4893 // (vextract (v4f32 s2v (f32 load $addr)), c) -> (f32 load $addr+c*size) 4894 // (vextract (v4f32 shuffle (load $addr), <1,u,u,u>), 0) -> (f32 load $addr) 4895 SDValue EltNo = N->getOperand(1); 4896 4897 if (isa<ConstantSDNode>(EltNo)) { 4898 unsigned Elt = cast<ConstantSDNode>(EltNo)->getZExtValue(); 4899 bool NewLoad = false; 4900 bool BCNumEltsChanged = false; 4901 MVT VT = InVec.getValueType(); 4902 MVT EVT = VT.getVectorElementType(); 4903 MVT LVT = EVT; 4904 if (InVec.getOpcode() == ISD::BIT_CONVERT) { 4905 MVT BCVT = InVec.getOperand(0).getValueType(); 4906 if (!BCVT.isVector() || EVT.bitsGT(BCVT.getVectorElementType())) 4907 return SDValue(); 4908 if (VT.getVectorNumElements() != BCVT.getVectorNumElements()) 4909 BCNumEltsChanged = true; 4910 InVec = InVec.getOperand(0); 4911 EVT = BCVT.getVectorElementType(); 4912 NewLoad = true; 4913 } 4914 4915 LoadSDNode *LN0 = NULL; 4916 if (ISD::isNormalLoad(InVec.getNode())) 4917 LN0 = cast<LoadSDNode>(InVec); 4918 else if (InVec.getOpcode() == ISD::SCALAR_TO_VECTOR && 4919 InVec.getOperand(0).getValueType() == EVT && 4920 ISD::isNormalLoad(InVec.getOperand(0).getNode())) { 4921 LN0 = cast<LoadSDNode>(InVec.getOperand(0)); 4922 } else if (InVec.getOpcode() == ISD::VECTOR_SHUFFLE) { 4923 // (vextract (vector_shuffle (load $addr), v2, <1, u, u, u>), 1) 4924 // => 4925 // (load $addr+1*size) 4926 4927 // If the bit convert changed the number of elements, it is unsafe 4928 // to examine the mask. 4929 if (BCNumEltsChanged) 4930 return SDValue(); 4931 unsigned Idx = cast<ConstantSDNode>(InVec.getOperand(2). 4932 getOperand(Elt))->getZExtValue(); 4933 unsigned NumElems = InVec.getOperand(2).getNumOperands(); 4934 InVec = (Idx < NumElems) ? InVec.getOperand(0) : InVec.getOperand(1); 4935 if (InVec.getOpcode() == ISD::BIT_CONVERT) 4936 InVec = InVec.getOperand(0); 4937 if (ISD::isNormalLoad(InVec.getNode())) { 4938 LN0 = cast<LoadSDNode>(InVec); 4939 Elt = (Idx < NumElems) ? Idx : Idx - NumElems; 4940 } 4941 } 4942 if (!LN0 || !LN0->hasOneUse() || LN0->isVolatile()) 4943 return SDValue(); 4944 4945 unsigned Align = LN0->getAlignment(); 4946 if (NewLoad) { 4947 // Check the resultant load doesn't need a higher alignment than the 4948 // original load. 4949 unsigned NewAlign = TLI.getTargetData()-> 4950 getABITypeAlignment(LVT.getTypeForMVT()); 4951 if (NewAlign > Align || !TLI.isOperationLegal(ISD::LOAD, LVT)) 4952 return SDValue(); 4953 Align = NewAlign; 4954 } 4955 4956 SDValue NewPtr = LN0->getBasePtr(); 4957 if (Elt) { 4958 unsigned PtrOff = LVT.getSizeInBits() * Elt / 8; 4959 MVT PtrType = NewPtr.getValueType(); 4960 if (TLI.isBigEndian()) 4961 PtrOff = VT.getSizeInBits() / 8 - PtrOff; 4962 NewPtr = DAG.getNode(ISD::ADD, PtrType, NewPtr, 4963 DAG.getConstant(PtrOff, PtrType)); 4964 } 4965 return DAG.getLoad(LVT, LN0->getChain(), NewPtr, 4966 LN0->getSrcValue(), LN0->getSrcValueOffset(), 4967 LN0->isVolatile(), Align); 4968 } 4969 return SDValue(); 4970} 4971 4972 4973SDValue DAGCombiner::visitBUILD_VECTOR(SDNode *N) { 4974 unsigned NumInScalars = N->getNumOperands(); 4975 MVT VT = N->getValueType(0); 4976 unsigned NumElts = VT.getVectorNumElements(); 4977 MVT EltType = VT.getVectorElementType(); 4978 4979 // Check to see if this is a BUILD_VECTOR of a bunch of EXTRACT_VECTOR_ELT 4980 // operations. If so, and if the EXTRACT_VECTOR_ELT vector inputs come from 4981 // at most two distinct vectors, turn this into a shuffle node. 4982 SDValue VecIn1, VecIn2; 4983 for (unsigned i = 0; i != NumInScalars; ++i) { 4984 // Ignore undef inputs. 4985 if (N->getOperand(i).getOpcode() == ISD::UNDEF) continue; 4986 4987 // If this input is something other than a EXTRACT_VECTOR_ELT with a 4988 // constant index, bail out. 4989 if (N->getOperand(i).getOpcode() != ISD::EXTRACT_VECTOR_ELT || 4990 !isa<ConstantSDNode>(N->getOperand(i).getOperand(1))) { 4991 VecIn1 = VecIn2 = SDValue(0, 0); 4992 break; 4993 } 4994 4995 // If the input vector type disagrees with the result of the build_vector, 4996 // we can't make a shuffle. 4997 SDValue ExtractedFromVec = N->getOperand(i).getOperand(0); 4998 if (ExtractedFromVec.getValueType() != VT) { 4999 VecIn1 = VecIn2 = SDValue(0, 0); 5000 break; 5001 } 5002 5003 // Otherwise, remember this. We allow up to two distinct input vectors. 5004 if (ExtractedFromVec == VecIn1 || ExtractedFromVec == VecIn2) 5005 continue; 5006 5007 if (VecIn1.getNode() == 0) { 5008 VecIn1 = ExtractedFromVec; 5009 } else if (VecIn2.getNode() == 0) { 5010 VecIn2 = ExtractedFromVec; 5011 } else { 5012 // Too many inputs. 5013 VecIn1 = VecIn2 = SDValue(0, 0); 5014 break; 5015 } 5016 } 5017 5018 // If everything is good, we can make a shuffle operation. 5019 if (VecIn1.getNode()) { 5020 SmallVector<SDValue, 8> BuildVecIndices; 5021 for (unsigned i = 0; i != NumInScalars; ++i) { 5022 if (N->getOperand(i).getOpcode() == ISD::UNDEF) { 5023 BuildVecIndices.push_back(DAG.getNode(ISD::UNDEF, TLI.getPointerTy())); 5024 continue; 5025 } 5026 5027 SDValue Extract = N->getOperand(i); 5028 5029 // If extracting from the first vector, just use the index directly. 5030 if (Extract.getOperand(0) == VecIn1) { 5031 BuildVecIndices.push_back(Extract.getOperand(1)); 5032 continue; 5033 } 5034 5035 // Otherwise, use InIdx + VecSize 5036 unsigned Idx = 5037 cast<ConstantSDNode>(Extract.getOperand(1))->getZExtValue(); 5038 BuildVecIndices.push_back(DAG.getIntPtrConstant(Idx+NumInScalars)); 5039 } 5040 5041 // Add count and size info. 5042 MVT BuildVecVT = MVT::getVectorVT(TLI.getPointerTy(), NumElts); 5043 if (!TLI.isTypeLegal(BuildVecVT) && LegalTypes) 5044 return SDValue(); 5045 5046 // Return the new VECTOR_SHUFFLE node. 5047 SDValue Ops[5]; 5048 Ops[0] = VecIn1; 5049 if (VecIn2.getNode()) { 5050 Ops[1] = VecIn2; 5051 } else { 5052 // Use an undef build_vector as input for the second operand. 5053 std::vector<SDValue> UnOps(NumInScalars, 5054 DAG.getNode(ISD::UNDEF, 5055 EltType)); 5056 Ops[1] = DAG.getNode(ISD::BUILD_VECTOR, VT, 5057 &UnOps[0], UnOps.size()); 5058 AddToWorkList(Ops[1].getNode()); 5059 } 5060 Ops[2] = DAG.getNode(ISD::BUILD_VECTOR, BuildVecVT, 5061 &BuildVecIndices[0], BuildVecIndices.size()); 5062 return DAG.getNode(ISD::VECTOR_SHUFFLE, VT, Ops, 3); 5063 } 5064 5065 return SDValue(); 5066} 5067 5068SDValue DAGCombiner::visitCONCAT_VECTORS(SDNode *N) { 5069 // TODO: Check to see if this is a CONCAT_VECTORS of a bunch of 5070 // EXTRACT_SUBVECTOR operations. If so, and if the EXTRACT_SUBVECTOR vector 5071 // inputs come from at most two distinct vectors, turn this into a shuffle 5072 // node. 5073 5074 // If we only have one input vector, we don't need to do any concatenation. 5075 if (N->getNumOperands() == 1) { 5076 return N->getOperand(0); 5077 } 5078 5079 return SDValue(); 5080} 5081 5082SDValue DAGCombiner::visitVECTOR_SHUFFLE(SDNode *N) { 5083 SDValue ShufMask = N->getOperand(2); 5084 unsigned NumElts = ShufMask.getNumOperands(); 5085 5086 SDValue N0 = N->getOperand(0); 5087 SDValue N1 = N->getOperand(1); 5088 5089 assert(N0.getValueType().getVectorNumElements() == NumElts && 5090 "Vector shuffle must be normalized in DAG"); 5091 5092 // If the shuffle mask is an identity operation on the LHS, return the LHS. 5093 bool isIdentity = true; 5094 for (unsigned i = 0; i != NumElts; ++i) { 5095 if (ShufMask.getOperand(i).getOpcode() != ISD::UNDEF && 5096 cast<ConstantSDNode>(ShufMask.getOperand(i))->getZExtValue() != i) { 5097 isIdentity = false; 5098 break; 5099 } 5100 } 5101 if (isIdentity) return N->getOperand(0); 5102 5103 // If the shuffle mask is an identity operation on the RHS, return the RHS. 5104 isIdentity = true; 5105 for (unsigned i = 0; i != NumElts; ++i) { 5106 if (ShufMask.getOperand(i).getOpcode() != ISD::UNDEF && 5107 cast<ConstantSDNode>(ShufMask.getOperand(i))->getZExtValue() != 5108 i+NumElts) { 5109 isIdentity = false; 5110 break; 5111 } 5112 } 5113 if (isIdentity) return N->getOperand(1); 5114 5115 // Check if the shuffle is a unary shuffle, i.e. one of the vectors is not 5116 // needed at all. 5117 bool isUnary = true; 5118 bool isSplat = true; 5119 int VecNum = -1; 5120 unsigned BaseIdx = 0; 5121 for (unsigned i = 0; i != NumElts; ++i) 5122 if (ShufMask.getOperand(i).getOpcode() != ISD::UNDEF) { 5123 unsigned Idx=cast<ConstantSDNode>(ShufMask.getOperand(i))->getZExtValue(); 5124 int V = (Idx < NumElts) ? 0 : 1; 5125 if (VecNum == -1) { 5126 VecNum = V; 5127 BaseIdx = Idx; 5128 } else { 5129 if (BaseIdx != Idx) 5130 isSplat = false; 5131 if (VecNum != V) { 5132 isUnary = false; 5133 break; 5134 } 5135 } 5136 } 5137 5138 // Normalize unary shuffle so the RHS is undef. 5139 if (isUnary && VecNum == 1) 5140 std::swap(N0, N1); 5141 5142 // If it is a splat, check if the argument vector is a build_vector with 5143 // all scalar elements the same. 5144 if (isSplat) { 5145 SDNode *V = N0.getNode(); 5146 5147 // If this is a bit convert that changes the element type of the vector but 5148 // not the number of vector elements, look through it. Be careful not to 5149 // look though conversions that change things like v4f32 to v2f64. 5150 if (V->getOpcode() == ISD::BIT_CONVERT) { 5151 SDValue ConvInput = V->getOperand(0); 5152 if (ConvInput.getValueType().isVector() && 5153 ConvInput.getValueType().getVectorNumElements() == NumElts) 5154 V = ConvInput.getNode(); 5155 } 5156 5157 if (V->getOpcode() == ISD::BUILD_VECTOR) { 5158 unsigned NumElems = V->getNumOperands(); 5159 if (NumElems > BaseIdx) { 5160 SDValue Base; 5161 bool AllSame = true; 5162 for (unsigned i = 0; i != NumElems; ++i) { 5163 if (V->getOperand(i).getOpcode() != ISD::UNDEF) { 5164 Base = V->getOperand(i); 5165 break; 5166 } 5167 } 5168 // Splat of <u, u, u, u>, return <u, u, u, u> 5169 if (!Base.getNode()) 5170 return N0; 5171 for (unsigned i = 0; i != NumElems; ++i) { 5172 if (V->getOperand(i) != Base) { 5173 AllSame = false; 5174 break; 5175 } 5176 } 5177 // Splat of <x, x, x, x>, return <x, x, x, x> 5178 if (AllSame) 5179 return N0; 5180 } 5181 } 5182 } 5183 5184 // If it is a unary or the LHS and the RHS are the same node, turn the RHS 5185 // into an undef. 5186 if (isUnary || N0 == N1) { 5187 // Check the SHUFFLE mask, mapping any inputs from the 2nd operand into the 5188 // first operand. 5189 SmallVector<SDValue, 8> MappedOps; 5190 for (unsigned i = 0; i != NumElts; ++i) { 5191 if (ShufMask.getOperand(i).getOpcode() == ISD::UNDEF || 5192 cast<ConstantSDNode>(ShufMask.getOperand(i))->getZExtValue() < 5193 NumElts) { 5194 MappedOps.push_back(ShufMask.getOperand(i)); 5195 } else { 5196 unsigned NewIdx = 5197 cast<ConstantSDNode>(ShufMask.getOperand(i))->getZExtValue() - 5198 NumElts; 5199 MappedOps.push_back(DAG.getConstant(NewIdx, 5200 ShufMask.getOperand(i).getValueType())); 5201 } 5202 } 5203 ShufMask = DAG.getNode(ISD::BUILD_VECTOR, ShufMask.getValueType(), 5204 &MappedOps[0], MappedOps.size()); 5205 AddToWorkList(ShufMask.getNode()); 5206 return DAG.getNode(ISD::VECTOR_SHUFFLE, N->getValueType(0), 5207 N0, 5208 DAG.getNode(ISD::UNDEF, N->getValueType(0)), 5209 ShufMask); 5210 } 5211 5212 return SDValue(); 5213} 5214 5215/// XformToShuffleWithZero - Returns a vector_shuffle if it able to transform 5216/// an AND to a vector_shuffle with the destination vector and a zero vector. 5217/// e.g. AND V, <0xffffffff, 0, 0xffffffff, 0>. ==> 5218/// vector_shuffle V, Zero, <0, 4, 2, 4> 5219SDValue DAGCombiner::XformToShuffleWithZero(SDNode *N) { 5220 SDValue LHS = N->getOperand(0); 5221 SDValue RHS = N->getOperand(1); 5222 if (N->getOpcode() == ISD::AND) { 5223 if (RHS.getOpcode() == ISD::BIT_CONVERT) 5224 RHS = RHS.getOperand(0); 5225 if (RHS.getOpcode() == ISD::BUILD_VECTOR) { 5226 std::vector<SDValue> IdxOps; 5227 unsigned NumOps = RHS.getNumOperands(); 5228 unsigned NumElts = NumOps; 5229 for (unsigned i = 0; i != NumElts; ++i) { 5230 SDValue Elt = RHS.getOperand(i); 5231 if (!isa<ConstantSDNode>(Elt)) 5232 return SDValue(); 5233 else if (cast<ConstantSDNode>(Elt)->isAllOnesValue()) 5234 IdxOps.push_back(DAG.getIntPtrConstant(i)); 5235 else if (cast<ConstantSDNode>(Elt)->isNullValue()) 5236 IdxOps.push_back(DAG.getIntPtrConstant(NumElts)); 5237 else 5238 return SDValue(); 5239 } 5240 5241 // Let's see if the target supports this vector_shuffle. 5242 if (!TLI.isVectorClearMaskLegal(IdxOps, TLI.getPointerTy(), DAG)) 5243 return SDValue(); 5244 5245 // Return the new VECTOR_SHUFFLE node. 5246 MVT EVT = RHS.getValueType().getVectorElementType(); 5247 MVT VT = MVT::getVectorVT(EVT, NumElts); 5248 MVT MaskVT = MVT::getVectorVT(TLI.getPointerTy(), NumElts); 5249 std::vector<SDValue> Ops; 5250 LHS = DAG.getNode(ISD::BIT_CONVERT, VT, LHS); 5251 Ops.push_back(LHS); 5252 AddToWorkList(LHS.getNode()); 5253 std::vector<SDValue> ZeroOps(NumElts, DAG.getConstant(0, EVT)); 5254 Ops.push_back(DAG.getNode(ISD::BUILD_VECTOR, VT, 5255 &ZeroOps[0], ZeroOps.size())); 5256 Ops.push_back(DAG.getNode(ISD::BUILD_VECTOR, MaskVT, 5257 &IdxOps[0], IdxOps.size())); 5258 SDValue Result = DAG.getNode(ISD::VECTOR_SHUFFLE, VT, 5259 &Ops[0], Ops.size()); 5260 if (VT != N->getValueType(0)) 5261 Result = DAG.getNode(ISD::BIT_CONVERT, N->getValueType(0), Result); 5262 return Result; 5263 } 5264 } 5265 return SDValue(); 5266} 5267 5268/// SimplifyVBinOp - Visit a binary vector operation, like ADD. 5269SDValue DAGCombiner::SimplifyVBinOp(SDNode *N) { 5270 // After legalize, the target may be depending on adds and other 5271 // binary ops to provide legal ways to construct constants or other 5272 // things. Simplifying them may result in a loss of legality. 5273 if (LegalOperations) return SDValue(); 5274 5275 MVT VT = N->getValueType(0); 5276 assert(VT.isVector() && "SimplifyVBinOp only works on vectors!"); 5277 5278 MVT EltType = VT.getVectorElementType(); 5279 SDValue LHS = N->getOperand(0); 5280 SDValue RHS = N->getOperand(1); 5281 SDValue Shuffle = XformToShuffleWithZero(N); 5282 if (Shuffle.getNode()) return Shuffle; 5283 5284 // If the LHS and RHS are BUILD_VECTOR nodes, see if we can constant fold 5285 // this operation. 5286 if (LHS.getOpcode() == ISD::BUILD_VECTOR && 5287 RHS.getOpcode() == ISD::BUILD_VECTOR) { 5288 SmallVector<SDValue, 8> Ops; 5289 for (unsigned i = 0, e = LHS.getNumOperands(); i != e; ++i) { 5290 SDValue LHSOp = LHS.getOperand(i); 5291 SDValue RHSOp = RHS.getOperand(i); 5292 // If these two elements can't be folded, bail out. 5293 if ((LHSOp.getOpcode() != ISD::UNDEF && 5294 LHSOp.getOpcode() != ISD::Constant && 5295 LHSOp.getOpcode() != ISD::ConstantFP) || 5296 (RHSOp.getOpcode() != ISD::UNDEF && 5297 RHSOp.getOpcode() != ISD::Constant && 5298 RHSOp.getOpcode() != ISD::ConstantFP)) 5299 break; 5300 // Can't fold divide by zero. 5301 if (N->getOpcode() == ISD::SDIV || N->getOpcode() == ISD::UDIV || 5302 N->getOpcode() == ISD::FDIV) { 5303 if ((RHSOp.getOpcode() == ISD::Constant && 5304 cast<ConstantSDNode>(RHSOp.getNode())->isNullValue()) || 5305 (RHSOp.getOpcode() == ISD::ConstantFP && 5306 cast<ConstantFPSDNode>(RHSOp.getNode())->getValueAPF().isZero())) 5307 break; 5308 } 5309 Ops.push_back(DAG.getNode(N->getOpcode(), EltType, LHSOp, RHSOp)); 5310 AddToWorkList(Ops.back().getNode()); 5311 assert((Ops.back().getOpcode() == ISD::UNDEF || 5312 Ops.back().getOpcode() == ISD::Constant || 5313 Ops.back().getOpcode() == ISD::ConstantFP) && 5314 "Scalar binop didn't fold!"); 5315 } 5316 5317 if (Ops.size() == LHS.getNumOperands()) { 5318 MVT VT = LHS.getValueType(); 5319 return DAG.getNode(ISD::BUILD_VECTOR, VT, &Ops[0], Ops.size()); 5320 } 5321 } 5322 5323 return SDValue(); 5324} 5325 5326SDValue DAGCombiner::SimplifySelect(SDValue N0, SDValue N1, SDValue N2){ 5327 assert(N0.getOpcode() ==ISD::SETCC && "First argument must be a SetCC node!"); 5328 5329 SDValue SCC = SimplifySelectCC(N0.getOperand(0), N0.getOperand(1), N1, N2, 5330 cast<CondCodeSDNode>(N0.getOperand(2))->get()); 5331 // If we got a simplified select_cc node back from SimplifySelectCC, then 5332 // break it down into a new SETCC node, and a new SELECT node, and then return 5333 // the SELECT node, since we were called with a SELECT node. 5334 if (SCC.getNode()) { 5335 // Check to see if we got a select_cc back (to turn into setcc/select). 5336 // Otherwise, just return whatever node we got back, like fabs. 5337 if (SCC.getOpcode() == ISD::SELECT_CC) { 5338 SDValue SETCC = DAG.getNode(ISD::SETCC, N0.getValueType(), 5339 SCC.getOperand(0), SCC.getOperand(1), 5340 SCC.getOperand(4)); 5341 AddToWorkList(SETCC.getNode()); 5342 return DAG.getNode(ISD::SELECT, SCC.getValueType(), SCC.getOperand(2), 5343 SCC.getOperand(3), SETCC); 5344 } 5345 return SCC; 5346 } 5347 return SDValue(); 5348} 5349 5350/// SimplifySelectOps - Given a SELECT or a SELECT_CC node, where LHS and RHS 5351/// are the two values being selected between, see if we can simplify the 5352/// select. Callers of this should assume that TheSelect is deleted if this 5353/// returns true. As such, they should return the appropriate thing (e.g. the 5354/// node) back to the top-level of the DAG combiner loop to avoid it being 5355/// looked at. 5356/// 5357bool DAGCombiner::SimplifySelectOps(SDNode *TheSelect, SDValue LHS, 5358 SDValue RHS) { 5359 5360 // If this is a select from two identical things, try to pull the operation 5361 // through the select. 5362 if (LHS.getOpcode() == RHS.getOpcode() && LHS.hasOneUse() && RHS.hasOneUse()){ 5363 // If this is a load and the token chain is identical, replace the select 5364 // of two loads with a load through a select of the address to load from. 5365 // This triggers in things like "select bool X, 10.0, 123.0" after the FP 5366 // constants have been dropped into the constant pool. 5367 if (LHS.getOpcode() == ISD::LOAD && 5368 // Do not let this transformation reduce the number of volatile loads. 5369 !cast<LoadSDNode>(LHS)->isVolatile() && 5370 !cast<LoadSDNode>(RHS)->isVolatile() && 5371 // Token chains must be identical. 5372 LHS.getOperand(0) == RHS.getOperand(0)) { 5373 LoadSDNode *LLD = cast<LoadSDNode>(LHS); 5374 LoadSDNode *RLD = cast<LoadSDNode>(RHS); 5375 5376 // If this is an EXTLOAD, the VT's must match. 5377 if (LLD->getMemoryVT() == RLD->getMemoryVT()) { 5378 // FIXME: this conflates two src values, discarding one. This is not 5379 // the right thing to do, but nothing uses srcvalues now. When they do, 5380 // turn SrcValue into a list of locations. 5381 SDValue Addr; 5382 if (TheSelect->getOpcode() == ISD::SELECT) { 5383 // Check that the condition doesn't reach either load. If so, folding 5384 // this will induce a cycle into the DAG. 5385 if (!LLD->isPredecessorOf(TheSelect->getOperand(0).getNode()) && 5386 !RLD->isPredecessorOf(TheSelect->getOperand(0).getNode())) { 5387 Addr = DAG.getNode(ISD::SELECT, LLD->getBasePtr().getValueType(), 5388 TheSelect->getOperand(0), LLD->getBasePtr(), 5389 RLD->getBasePtr()); 5390 } 5391 } else { 5392 // Check that the condition doesn't reach either load. If so, folding 5393 // this will induce a cycle into the DAG. 5394 if (!LLD->isPredecessorOf(TheSelect->getOperand(0).getNode()) && 5395 !RLD->isPredecessorOf(TheSelect->getOperand(0).getNode()) && 5396 !LLD->isPredecessorOf(TheSelect->getOperand(1).getNode()) && 5397 !RLD->isPredecessorOf(TheSelect->getOperand(1).getNode())) { 5398 Addr = DAG.getNode(ISD::SELECT_CC, LLD->getBasePtr().getValueType(), 5399 TheSelect->getOperand(0), 5400 TheSelect->getOperand(1), 5401 LLD->getBasePtr(), RLD->getBasePtr(), 5402 TheSelect->getOperand(4)); 5403 } 5404 } 5405 5406 if (Addr.getNode()) { 5407 SDValue Load; 5408 if (LLD->getExtensionType() == ISD::NON_EXTLOAD) 5409 Load = DAG.getLoad(TheSelect->getValueType(0), LLD->getChain(), 5410 Addr,LLD->getSrcValue(), 5411 LLD->getSrcValueOffset(), 5412 LLD->isVolatile(), 5413 LLD->getAlignment()); 5414 else { 5415 Load = DAG.getExtLoad(LLD->getExtensionType(), 5416 TheSelect->getValueType(0), 5417 LLD->getChain(), Addr, LLD->getSrcValue(), 5418 LLD->getSrcValueOffset(), 5419 LLD->getMemoryVT(), 5420 LLD->isVolatile(), 5421 LLD->getAlignment()); 5422 } 5423 // Users of the select now use the result of the load. 5424 CombineTo(TheSelect, Load); 5425 5426 // Users of the old loads now use the new load's chain. We know the 5427 // old-load value is dead now. 5428 CombineTo(LHS.getNode(), Load.getValue(0), Load.getValue(1)); 5429 CombineTo(RHS.getNode(), Load.getValue(0), Load.getValue(1)); 5430 return true; 5431 } 5432 } 5433 } 5434 } 5435 5436 return false; 5437} 5438 5439SDValue DAGCombiner::SimplifySelectCC(SDValue N0, SDValue N1, 5440 SDValue N2, SDValue N3, 5441 ISD::CondCode CC, bool NotExtCompare) { 5442 5443 MVT VT = N2.getValueType(); 5444 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.getNode()); 5445 ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(N2.getNode()); 5446 ConstantSDNode *N3C = dyn_cast<ConstantSDNode>(N3.getNode()); 5447 5448 // Determine if the condition we're dealing with is constant 5449 SDValue SCC = SimplifySetCC(TLI.getSetCCResultType(N0.getValueType()), 5450 N0, N1, CC, false); 5451 if (SCC.getNode()) AddToWorkList(SCC.getNode()); 5452 ConstantSDNode *SCCC = dyn_cast_or_null<ConstantSDNode>(SCC.getNode()); 5453 5454 // fold select_cc true, x, y -> x 5455 if (SCCC && !SCCC->isNullValue()) 5456 return N2; 5457 // fold select_cc false, x, y -> y 5458 if (SCCC && SCCC->isNullValue()) 5459 return N3; 5460 5461 // Check to see if we can simplify the select into an fabs node 5462 if (ConstantFPSDNode *CFP = dyn_cast<ConstantFPSDNode>(N1)) { 5463 // Allow either -0.0 or 0.0 5464 if (CFP->getValueAPF().isZero()) { 5465 // select (setg[te] X, +/-0.0), X, fneg(X) -> fabs 5466 if ((CC == ISD::SETGE || CC == ISD::SETGT) && 5467 N0 == N2 && N3.getOpcode() == ISD::FNEG && 5468 N2 == N3.getOperand(0)) 5469 return DAG.getNode(ISD::FABS, VT, N0); 5470 5471 // select (setl[te] X, +/-0.0), fneg(X), X -> fabs 5472 if ((CC == ISD::SETLT || CC == ISD::SETLE) && 5473 N0 == N3 && N2.getOpcode() == ISD::FNEG && 5474 N2.getOperand(0) == N3) 5475 return DAG.getNode(ISD::FABS, VT, N3); 5476 } 5477 } 5478 5479 // Check to see if we can perform the "gzip trick", transforming 5480 // select_cc setlt X, 0, A, 0 -> and (sra X, size(X)-1), A 5481 if (N1C && N3C && N3C->isNullValue() && CC == ISD::SETLT && 5482 N0.getValueType().isInteger() && 5483 N2.getValueType().isInteger() && 5484 (N1C->isNullValue() || // (a < 0) ? b : 0 5485 (N1C->getAPIntValue() == 1 && N0 == N2))) { // (a < 1) ? a : 0 5486 MVT XType = N0.getValueType(); 5487 MVT AType = N2.getValueType(); 5488 if (XType.bitsGE(AType)) { 5489 // and (sra X, size(X)-1, A) -> "and (srl X, C2), A" iff A is a 5490 // single-bit constant. 5491 if (N2C && ((N2C->getAPIntValue() & (N2C->getAPIntValue()-1)) == 0)) { 5492 unsigned ShCtV = N2C->getAPIntValue().logBase2(); 5493 ShCtV = XType.getSizeInBits()-ShCtV-1; 5494 SDValue ShCt = DAG.getConstant(ShCtV, TLI.getShiftAmountTy()); 5495 SDValue Shift = DAG.getNode(ISD::SRL, XType, N0, ShCt); 5496 AddToWorkList(Shift.getNode()); 5497 if (XType.bitsGT(AType)) { 5498 Shift = DAG.getNode(ISD::TRUNCATE, AType, Shift); 5499 AddToWorkList(Shift.getNode()); 5500 } 5501 return DAG.getNode(ISD::AND, AType, Shift, N2); 5502 } 5503 SDValue Shift = DAG.getNode(ISD::SRA, XType, N0, 5504 DAG.getConstant(XType.getSizeInBits()-1, 5505 TLI.getShiftAmountTy())); 5506 AddToWorkList(Shift.getNode()); 5507 if (XType.bitsGT(AType)) { 5508 Shift = DAG.getNode(ISD::TRUNCATE, AType, Shift); 5509 AddToWorkList(Shift.getNode()); 5510 } 5511 return DAG.getNode(ISD::AND, AType, Shift, N2); 5512 } 5513 } 5514 5515 // fold select C, 16, 0 -> shl C, 4 5516 if (N2C && N3C && N3C->isNullValue() && N2C->getAPIntValue().isPowerOf2() && 5517 TLI.getBooleanContents() == TargetLowering::ZeroOrOneBooleanContent) { 5518 5519 // If the caller doesn't want us to simplify this into a zext of a compare, 5520 // don't do it. 5521 if (NotExtCompare && N2C->getAPIntValue() == 1) 5522 return SDValue(); 5523 5524 // Get a SetCC of the condition 5525 // FIXME: Should probably make sure that setcc is legal if we ever have a 5526 // target where it isn't. 5527 SDValue Temp, SCC; 5528 // cast from setcc result type to select result type 5529 if (LegalTypes) { 5530 SCC = DAG.getSetCC(TLI.getSetCCResultType(N0.getValueType()), 5531 N0, N1, CC); 5532 if (N2.getValueType().bitsLT(SCC.getValueType())) 5533 Temp = DAG.getZeroExtendInReg(SCC, N2.getValueType()); 5534 else 5535 Temp = DAG.getNode(ISD::ZERO_EXTEND, N2.getValueType(), SCC); 5536 } else { 5537 SCC = DAG.getSetCC(MVT::i1, N0, N1, CC); 5538 Temp = DAG.getNode(ISD::ZERO_EXTEND, N2.getValueType(), SCC); 5539 } 5540 AddToWorkList(SCC.getNode()); 5541 AddToWorkList(Temp.getNode()); 5542 5543 if (N2C->getAPIntValue() == 1) 5544 return Temp; 5545 // shl setcc result by log2 n2c 5546 return DAG.getNode(ISD::SHL, N2.getValueType(), Temp, 5547 DAG.getConstant(N2C->getAPIntValue().logBase2(), 5548 TLI.getShiftAmountTy())); 5549 } 5550 5551 // Check to see if this is the equivalent of setcc 5552 // FIXME: Turn all of these into setcc if setcc if setcc is legal 5553 // otherwise, go ahead with the folds. 5554 if (0 && N3C && N3C->isNullValue() && N2C && (N2C->getAPIntValue() == 1ULL)) { 5555 MVT XType = N0.getValueType(); 5556 if (!LegalOperations || 5557 TLI.isOperationLegal(ISD::SETCC, TLI.getSetCCResultType(XType))) { 5558 SDValue Res = DAG.getSetCC(TLI.getSetCCResultType(XType), N0, N1, CC); 5559 if (Res.getValueType() != VT) 5560 Res = DAG.getNode(ISD::ZERO_EXTEND, VT, Res); 5561 return Res; 5562 } 5563 5564 // seteq X, 0 -> srl (ctlz X, log2(size(X))) 5565 if (N1C && N1C->isNullValue() && CC == ISD::SETEQ && 5566 (!LegalOperations || 5567 TLI.isOperationLegal(ISD::CTLZ, XType))) { 5568 SDValue Ctlz = DAG.getNode(ISD::CTLZ, XType, N0); 5569 return DAG.getNode(ISD::SRL, XType, Ctlz, 5570 DAG.getConstant(Log2_32(XType.getSizeInBits()), 5571 TLI.getShiftAmountTy())); 5572 } 5573 // setgt X, 0 -> srl (and (-X, ~X), size(X)-1) 5574 if (N1C && N1C->isNullValue() && CC == ISD::SETGT) { 5575 SDValue NegN0 = DAG.getNode(ISD::SUB, XType, DAG.getConstant(0, XType), 5576 N0); 5577 SDValue NotN0 = DAG.getNOT(N0, XType); 5578 return DAG.getNode(ISD::SRL, XType, 5579 DAG.getNode(ISD::AND, XType, NegN0, NotN0), 5580 DAG.getConstant(XType.getSizeInBits()-1, 5581 TLI.getShiftAmountTy())); 5582 } 5583 // setgt X, -1 -> xor (srl (X, size(X)-1), 1) 5584 if (N1C && N1C->isAllOnesValue() && CC == ISD::SETGT) { 5585 SDValue Sign = DAG.getNode(ISD::SRL, XType, N0, 5586 DAG.getConstant(XType.getSizeInBits()-1, 5587 TLI.getShiftAmountTy())); 5588 return DAG.getNode(ISD::XOR, XType, Sign, DAG.getConstant(1, XType)); 5589 } 5590 } 5591 5592 // Check to see if this is an integer abs. select_cc setl[te] X, 0, -X, X -> 5593 // Y = sra (X, size(X)-1); xor (add (X, Y), Y) 5594 if (N1C && N1C->isNullValue() && (CC == ISD::SETLT || CC == ISD::SETLE) && 5595 N0 == N3 && N2.getOpcode() == ISD::SUB && N0 == N2.getOperand(1) && 5596 N2.getOperand(0) == N1 && N0.getValueType().isInteger()) { 5597 MVT XType = N0.getValueType(); 5598 SDValue Shift = DAG.getNode(ISD::SRA, XType, N0, 5599 DAG.getConstant(XType.getSizeInBits()-1, 5600 TLI.getShiftAmountTy())); 5601 SDValue Add = DAG.getNode(ISD::ADD, XType, N0, Shift); 5602 AddToWorkList(Shift.getNode()); 5603 AddToWorkList(Add.getNode()); 5604 return DAG.getNode(ISD::XOR, XType, Add, Shift); 5605 } 5606 // Check to see if this is an integer abs. select_cc setgt X, -1, X, -X -> 5607 // Y = sra (X, size(X)-1); xor (add (X, Y), Y) 5608 if (N1C && N1C->isAllOnesValue() && CC == ISD::SETGT && 5609 N0 == N2 && N3.getOpcode() == ISD::SUB && N0 == N3.getOperand(1)) { 5610 if (ConstantSDNode *SubC = dyn_cast<ConstantSDNode>(N3.getOperand(0))) { 5611 MVT XType = N0.getValueType(); 5612 if (SubC->isNullValue() && XType.isInteger()) { 5613 SDValue Shift = DAG.getNode(ISD::SRA, XType, N0, 5614 DAG.getConstant(XType.getSizeInBits()-1, 5615 TLI.getShiftAmountTy())); 5616 SDValue Add = DAG.getNode(ISD::ADD, XType, N0, Shift); 5617 AddToWorkList(Shift.getNode()); 5618 AddToWorkList(Add.getNode()); 5619 return DAG.getNode(ISD::XOR, XType, Add, Shift); 5620 } 5621 } 5622 } 5623 5624 return SDValue(); 5625} 5626 5627/// SimplifySetCC - This is a stub for TargetLowering::SimplifySetCC. 5628SDValue DAGCombiner::SimplifySetCC(MVT VT, SDValue N0, 5629 SDValue N1, ISD::CondCode Cond, 5630 bool foldBooleans) { 5631 TargetLowering::DAGCombinerInfo 5632 DagCombineInfo(DAG, Level == Unrestricted, false, this); 5633 return TLI.SimplifySetCC(VT, N0, N1, Cond, foldBooleans, DagCombineInfo); 5634} 5635 5636/// BuildSDIVSequence - Given an ISD::SDIV node expressing a divide by constant, 5637/// return a DAG expression to select that will generate the same value by 5638/// multiplying by a magic number. See: 5639/// <http://the.wall.riscom.net/books/proc/ppc/cwg/code2.html> 5640SDValue DAGCombiner::BuildSDIV(SDNode *N) { 5641 std::vector<SDNode*> Built; 5642 SDValue S = TLI.BuildSDIV(N, DAG, &Built); 5643 5644 for (std::vector<SDNode*>::iterator ii = Built.begin(), ee = Built.end(); 5645 ii != ee; ++ii) 5646 AddToWorkList(*ii); 5647 return S; 5648} 5649 5650/// BuildUDIVSequence - Given an ISD::UDIV node expressing a divide by constant, 5651/// return a DAG expression to select that will generate the same value by 5652/// multiplying by a magic number. See: 5653/// <http://the.wall.riscom.net/books/proc/ppc/cwg/code2.html> 5654SDValue DAGCombiner::BuildUDIV(SDNode *N) { 5655 std::vector<SDNode*> Built; 5656 SDValue S = TLI.BuildUDIV(N, DAG, &Built); 5657 5658 for (std::vector<SDNode*>::iterator ii = Built.begin(), ee = Built.end(); 5659 ii != ee; ++ii) 5660 AddToWorkList(*ii); 5661 return S; 5662} 5663 5664/// FindBaseOffset - Return true if base is known not to alias with anything 5665/// but itself. Provides base object and offset as results. 5666static bool FindBaseOffset(SDValue Ptr, SDValue &Base, int64_t &Offset) { 5667 // Assume it is a primitive operation. 5668 Base = Ptr; Offset = 0; 5669 5670 // If it's an adding a simple constant then integrate the offset. 5671 if (Base.getOpcode() == ISD::ADD) { 5672 if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Base.getOperand(1))) { 5673 Base = Base.getOperand(0); 5674 Offset += C->getZExtValue(); 5675 } 5676 } 5677 5678 // If it's any of the following then it can't alias with anything but itself. 5679 return isa<FrameIndexSDNode>(Base) || 5680 isa<ConstantPoolSDNode>(Base) || 5681 isa<GlobalAddressSDNode>(Base); 5682} 5683 5684/// isAlias - Return true if there is any possibility that the two addresses 5685/// overlap. 5686bool DAGCombiner::isAlias(SDValue Ptr1, int64_t Size1, 5687 const Value *SrcValue1, int SrcValueOffset1, 5688 SDValue Ptr2, int64_t Size2, 5689 const Value *SrcValue2, int SrcValueOffset2) 5690{ 5691 // If they are the same then they must be aliases. 5692 if (Ptr1 == Ptr2) return true; 5693 5694 // Gather base node and offset information. 5695 SDValue Base1, Base2; 5696 int64_t Offset1, Offset2; 5697 bool KnownBase1 = FindBaseOffset(Ptr1, Base1, Offset1); 5698 bool KnownBase2 = FindBaseOffset(Ptr2, Base2, Offset2); 5699 5700 // If they have a same base address then... 5701 if (Base1 == Base2) { 5702 // Check to see if the addresses overlap. 5703 return!((Offset1 + Size1) <= Offset2 || (Offset2 + Size2) <= Offset1); 5704 } 5705 5706 // If we know both bases then they can't alias. 5707 if (KnownBase1 && KnownBase2) return false; 5708 5709 if (CombinerGlobalAA) { 5710 // Use alias analysis information. 5711 int64_t MinOffset = std::min(SrcValueOffset1, SrcValueOffset2); 5712 int64_t Overlap1 = Size1 + SrcValueOffset1 - MinOffset; 5713 int64_t Overlap2 = Size2 + SrcValueOffset2 - MinOffset; 5714 AliasAnalysis::AliasResult AAResult = 5715 AA.alias(SrcValue1, Overlap1, SrcValue2, Overlap2); 5716 if (AAResult == AliasAnalysis::NoAlias) 5717 return false; 5718 } 5719 5720 // Otherwise we have to assume they alias. 5721 return true; 5722} 5723 5724/// FindAliasInfo - Extracts the relevant alias information from the memory 5725/// node. Returns true if the operand was a load. 5726bool DAGCombiner::FindAliasInfo(SDNode *N, 5727 SDValue &Ptr, int64_t &Size, 5728 const Value *&SrcValue, int &SrcValueOffset) { 5729 if (LoadSDNode *LD = dyn_cast<LoadSDNode>(N)) { 5730 Ptr = LD->getBasePtr(); 5731 Size = LD->getMemoryVT().getSizeInBits() >> 3; 5732 SrcValue = LD->getSrcValue(); 5733 SrcValueOffset = LD->getSrcValueOffset(); 5734 return true; 5735 } else if (StoreSDNode *ST = dyn_cast<StoreSDNode>(N)) { 5736 Ptr = ST->getBasePtr(); 5737 Size = ST->getMemoryVT().getSizeInBits() >> 3; 5738 SrcValue = ST->getSrcValue(); 5739 SrcValueOffset = ST->getSrcValueOffset(); 5740 } else { 5741 assert(0 && "FindAliasInfo expected a memory operand"); 5742 } 5743 5744 return false; 5745} 5746 5747/// GatherAllAliases - Walk up chain skipping non-aliasing memory nodes, 5748/// looking for aliasing nodes and adding them to the Aliases vector. 5749void DAGCombiner::GatherAllAliases(SDNode *N, SDValue OriginalChain, 5750 SmallVector<SDValue, 8> &Aliases) { 5751 SmallVector<SDValue, 8> Chains; // List of chains to visit. 5752 std::set<SDNode *> Visited; // Visited node set. 5753 5754 // Get alias information for node. 5755 SDValue Ptr; 5756 int64_t Size; 5757 const Value *SrcValue; 5758 int SrcValueOffset; 5759 bool IsLoad = FindAliasInfo(N, Ptr, Size, SrcValue, SrcValueOffset); 5760 5761 // Starting off. 5762 Chains.push_back(OriginalChain); 5763 5764 // Look at each chain and determine if it is an alias. If so, add it to the 5765 // aliases list. If not, then continue up the chain looking for the next 5766 // candidate. 5767 while (!Chains.empty()) { 5768 SDValue Chain = Chains.back(); 5769 Chains.pop_back(); 5770 5771 // Don't bother if we've been before. 5772 if (Visited.find(Chain.getNode()) != Visited.end()) continue; 5773 Visited.insert(Chain.getNode()); 5774 5775 switch (Chain.getOpcode()) { 5776 case ISD::EntryToken: 5777 // Entry token is ideal chain operand, but handled in FindBetterChain. 5778 break; 5779 5780 case ISD::LOAD: 5781 case ISD::STORE: { 5782 // Get alias information for Chain. 5783 SDValue OpPtr; 5784 int64_t OpSize; 5785 const Value *OpSrcValue; 5786 int OpSrcValueOffset; 5787 bool IsOpLoad = FindAliasInfo(Chain.getNode(), OpPtr, OpSize, 5788 OpSrcValue, OpSrcValueOffset); 5789 5790 // If chain is alias then stop here. 5791 if (!(IsLoad && IsOpLoad) && 5792 isAlias(Ptr, Size, SrcValue, SrcValueOffset, 5793 OpPtr, OpSize, OpSrcValue, OpSrcValueOffset)) { 5794 Aliases.push_back(Chain); 5795 } else { 5796 // Look further up the chain. 5797 Chains.push_back(Chain.getOperand(0)); 5798 // Clean up old chain. 5799 AddToWorkList(Chain.getNode()); 5800 } 5801 break; 5802 } 5803 5804 case ISD::TokenFactor: 5805 // We have to check each of the operands of the token factor, so we queue 5806 // then up. Adding the operands to the queue (stack) in reverse order 5807 // maintains the original order and increases the likelihood that getNode 5808 // will find a matching token factor (CSE.) 5809 for (unsigned n = Chain.getNumOperands(); n;) 5810 Chains.push_back(Chain.getOperand(--n)); 5811 // Eliminate the token factor if we can. 5812 AddToWorkList(Chain.getNode()); 5813 break; 5814 5815 default: 5816 // For all other instructions we will just have to take what we can get. 5817 Aliases.push_back(Chain); 5818 break; 5819 } 5820 } 5821} 5822 5823/// FindBetterChain - Walk up chain skipping non-aliasing memory nodes, looking 5824/// for a better chain (aliasing node.) 5825SDValue DAGCombiner::FindBetterChain(SDNode *N, SDValue OldChain) { 5826 SmallVector<SDValue, 8> Aliases; // Ops for replacing token factor. 5827 5828 // Accumulate all the aliases to this node. 5829 GatherAllAliases(N, OldChain, Aliases); 5830 5831 if (Aliases.size() == 0) { 5832 // If no operands then chain to entry token. 5833 return DAG.getEntryNode(); 5834 } else if (Aliases.size() == 1) { 5835 // If a single operand then chain to it. We don't need to revisit it. 5836 return Aliases[0]; 5837 } 5838 5839 // Construct a custom tailored token factor. 5840 SDValue NewChain = DAG.getNode(ISD::TokenFactor, MVT::Other, 5841 &Aliases[0], Aliases.size()); 5842 5843 // Make sure the old chain gets cleaned up. 5844 if (NewChain != OldChain) AddToWorkList(OldChain.getNode()); 5845 5846 return NewChain; 5847} 5848 5849// SelectionDAG::Combine - This is the entry point for the file. 5850// 5851void SelectionDAG::Combine(CombineLevel Level, AliasAnalysis &AA, bool Fast) { 5852 /// run - This is the main entry point to this class. 5853 /// 5854 DAGCombiner(*this, AA, Fast).Run(Level); 5855} 5856