1 //===- BBVectorize.cpp - A Basic-Block Vectorizer -------------------------===// 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 file implements a basic-block vectorization pass. The algorithm was 11 // inspired by that used by the Vienna MAP Vectorizor by Franchetti and Kral, 12 // et al. It works by looking for chains of pairable operations and then 13 // pairing them. 14 // 15 //===----------------------------------------------------------------------===// 16 17 #define BBV_NAME "bb-vectorize" 18 #define DEBUG_TYPE BBV_NAME 19 #include "llvm/Transforms/Vectorize.h" 20 #include "llvm/ADT/DenseMap.h" 21 #include "llvm/ADT/DenseSet.h" 22 #include "llvm/ADT/STLExtras.h" 23 #include "llvm/ADT/SmallSet.h" 24 #include "llvm/ADT/SmallVector.h" 25 #include "llvm/ADT/Statistic.h" 26 #include "llvm/ADT/StringExtras.h" 27 #include "llvm/Analysis/AliasAnalysis.h" 28 #include "llvm/Analysis/AliasSetTracker.h" 29 #include "llvm/Analysis/Dominators.h" 30 #include "llvm/Analysis/ScalarEvolution.h" 31 #include "llvm/Analysis/ScalarEvolutionExpressions.h" 32 #include "llvm/Analysis/TargetTransformInfo.h" 33 #include "llvm/Analysis/ValueTracking.h" 34 #include "llvm/IR/Constants.h" 35 #include "llvm/IR/DataLayout.h" 36 #include "llvm/IR/DerivedTypes.h" 37 #include "llvm/IR/Function.h" 38 #include "llvm/IR/Instructions.h" 39 #include "llvm/IR/IntrinsicInst.h" 40 #include "llvm/IR/Intrinsics.h" 41 #include "llvm/IR/LLVMContext.h" 42 #include "llvm/IR/Metadata.h" 43 #include "llvm/IR/Type.h" 44 #include "llvm/Pass.h" 45 #include "llvm/Support/CommandLine.h" 46 #include "llvm/Support/Debug.h" 47 #include "llvm/Support/ValueHandle.h" 48 #include "llvm/Support/raw_ostream.h" 49 #include "llvm/Transforms/Utils/Local.h" 50 #include <algorithm> 51 using namespace llvm; 52 53 static cl::opt<bool> 54 IgnoreTargetInfo("bb-vectorize-ignore-target-info", cl::init(false), 55 cl::Hidden, cl::desc("Ignore target information")); 56 57 static cl::opt<unsigned> 58 ReqChainDepth("bb-vectorize-req-chain-depth", cl::init(6), cl::Hidden, 59 cl::desc("The required chain depth for vectorization")); 60 61 static cl::opt<bool> 62 UseChainDepthWithTI("bb-vectorize-use-chain-depth", cl::init(false), 63 cl::Hidden, cl::desc("Use the chain depth requirement with" 64 " target information")); 65 66 static cl::opt<unsigned> 67 SearchLimit("bb-vectorize-search-limit", cl::init(400), cl::Hidden, 68 cl::desc("The maximum search distance for instruction pairs")); 69 70 static cl::opt<bool> 71 SplatBreaksChain("bb-vectorize-splat-breaks-chain", cl::init(false), cl::Hidden, 72 cl::desc("Replicating one element to a pair breaks the chain")); 73 74 static cl::opt<unsigned> 75 VectorBits("bb-vectorize-vector-bits", cl::init(128), cl::Hidden, 76 cl::desc("The size of the native vector registers")); 77 78 static cl::opt<unsigned> 79 MaxIter("bb-vectorize-max-iter", cl::init(0), cl::Hidden, 80 cl::desc("The maximum number of pairing iterations")); 81 82 static cl::opt<bool> 83 Pow2LenOnly("bb-vectorize-pow2-len-only", cl::init(false), cl::Hidden, 84 cl::desc("Don't try to form non-2^n-length vectors")); 85 86 static cl::opt<unsigned> 87 MaxInsts("bb-vectorize-max-instr-per-group", cl::init(500), cl::Hidden, 88 cl::desc("The maximum number of pairable instructions per group")); 89 90 static cl::opt<unsigned> 91 MaxPairs("bb-vectorize-max-pairs-per-group", cl::init(3000), cl::Hidden, 92 cl::desc("The maximum number of candidate instruction pairs per group")); 93 94 static cl::opt<unsigned> 95 MaxCandPairsForCycleCheck("bb-vectorize-max-cycle-check-pairs", cl::init(200), 96 cl::Hidden, cl::desc("The maximum number of candidate pairs with which to use" 97 " a full cycle check")); 98 99 static cl::opt<bool> 100 NoBools("bb-vectorize-no-bools", cl::init(false), cl::Hidden, 101 cl::desc("Don't try to vectorize boolean (i1) values")); 102 103 static cl::opt<bool> 104 NoInts("bb-vectorize-no-ints", cl::init(false), cl::Hidden, 105 cl::desc("Don't try to vectorize integer values")); 106 107 static cl::opt<bool> 108 NoFloats("bb-vectorize-no-floats", cl::init(false), cl::Hidden, 109 cl::desc("Don't try to vectorize floating-point values")); 110 111 // FIXME: This should default to false once pointer vector support works. 112 static cl::opt<bool> 113 NoPointers("bb-vectorize-no-pointers", cl::init(/*false*/ true), cl::Hidden, 114 cl::desc("Don't try to vectorize pointer values")); 115 116 static cl::opt<bool> 117 NoCasts("bb-vectorize-no-casts", cl::init(false), cl::Hidden, 118 cl::desc("Don't try to vectorize casting (conversion) operations")); 119 120 static cl::opt<bool> 121 NoMath("bb-vectorize-no-math", cl::init(false), cl::Hidden, 122 cl::desc("Don't try to vectorize floating-point math intrinsics")); 123 124 static cl::opt<bool> 125 NoFMA("bb-vectorize-no-fma", cl::init(false), cl::Hidden, 126 cl::desc("Don't try to vectorize the fused-multiply-add intrinsic")); 127 128 static cl::opt<bool> 129 NoSelect("bb-vectorize-no-select", cl::init(false), cl::Hidden, 130 cl::desc("Don't try to vectorize select instructions")); 131 132 static cl::opt<bool> 133 NoCmp("bb-vectorize-no-cmp", cl::init(false), cl::Hidden, 134 cl::desc("Don't try to vectorize comparison instructions")); 135 136 static cl::opt<bool> 137 NoGEP("bb-vectorize-no-gep", cl::init(false), cl::Hidden, 138 cl::desc("Don't try to vectorize getelementptr instructions")); 139 140 static cl::opt<bool> 141 NoMemOps("bb-vectorize-no-mem-ops", cl::init(false), cl::Hidden, 142 cl::desc("Don't try to vectorize loads and stores")); 143 144 static cl::opt<bool> 145 AlignedOnly("bb-vectorize-aligned-only", cl::init(false), cl::Hidden, 146 cl::desc("Only generate aligned loads and stores")); 147 148 static cl::opt<bool> 149 NoMemOpBoost("bb-vectorize-no-mem-op-boost", 150 cl::init(false), cl::Hidden, 151 cl::desc("Don't boost the chain-depth contribution of loads and stores")); 152 153 static cl::opt<bool> 154 FastDep("bb-vectorize-fast-dep", cl::init(false), cl::Hidden, 155 cl::desc("Use a fast instruction dependency analysis")); 156 157 #ifndef NDEBUG 158 static cl::opt<bool> 159 DebugInstructionExamination("bb-vectorize-debug-instruction-examination", 160 cl::init(false), cl::Hidden, 161 cl::desc("When debugging is enabled, output information on the" 162 " instruction-examination process")); 163 static cl::opt<bool> 164 DebugCandidateSelection("bb-vectorize-debug-candidate-selection", 165 cl::init(false), cl::Hidden, 166 cl::desc("When debugging is enabled, output information on the" 167 " candidate-selection process")); 168 static cl::opt<bool> 169 DebugPairSelection("bb-vectorize-debug-pair-selection", 170 cl::init(false), cl::Hidden, 171 cl::desc("When debugging is enabled, output information on the" 172 " pair-selection process")); 173 static cl::opt<bool> 174 DebugCycleCheck("bb-vectorize-debug-cycle-check", 175 cl::init(false), cl::Hidden, 176 cl::desc("When debugging is enabled, output information on the" 177 " cycle-checking process")); 178 179 static cl::opt<bool> 180 PrintAfterEveryPair("bb-vectorize-debug-print-after-every-pair", 181 cl::init(false), cl::Hidden, 182 cl::desc("When debugging is enabled, dump the basic block after" 183 " every pair is fused")); 184 #endif 185 186 STATISTIC(NumFusedOps, "Number of operations fused by bb-vectorize"); 187 188 namespace { 189 struct BBVectorize : public BasicBlockPass { 190 static char ID; // Pass identification, replacement for typeid 191 192 const VectorizeConfig Config; 193 194 BBVectorize(const VectorizeConfig &C = VectorizeConfig()) 195 : BasicBlockPass(ID), Config(C) { 196 initializeBBVectorizePass(*PassRegistry::getPassRegistry()); 197 } 198 199 BBVectorize(Pass *P, const VectorizeConfig &C) 200 : BasicBlockPass(ID), Config(C) { 201 AA = &P->getAnalysis<AliasAnalysis>(); 202 DT = &P->getAnalysis<DominatorTree>(); 203 SE = &P->getAnalysis<ScalarEvolution>(); 204 TD = P->getAnalysisIfAvailable<DataLayout>(); 205 TTI = IgnoreTargetInfo ? 0 : &P->getAnalysis<TargetTransformInfo>(); 206 } 207 208 typedef std::pair<Value *, Value *> ValuePair; 209 typedef std::pair<ValuePair, int> ValuePairWithCost; 210 typedef std::pair<ValuePair, size_t> ValuePairWithDepth; 211 typedef std::pair<ValuePair, ValuePair> VPPair; // A ValuePair pair 212 typedef std::pair<VPPair, unsigned> VPPairWithType; 213 214 AliasAnalysis *AA; 215 DominatorTree *DT; 216 ScalarEvolution *SE; 217 DataLayout *TD; 218 const TargetTransformInfo *TTI; 219 220 // FIXME: const correct? 221 222 bool vectorizePairs(BasicBlock &BB, bool NonPow2Len = false); 223 224 bool getCandidatePairs(BasicBlock &BB, 225 BasicBlock::iterator &Start, 226 DenseMap<Value *, std::vector<Value *> > &CandidatePairs, 227 DenseSet<ValuePair> &FixedOrderPairs, 228 DenseMap<ValuePair, int> &CandidatePairCostSavings, 229 std::vector<Value *> &PairableInsts, bool NonPow2Len); 230 231 // FIXME: The current implementation does not account for pairs that 232 // are connected in multiple ways. For example: 233 // C1 = A1 / A2; C2 = A2 / A1 (which may be both direct and a swap) 234 enum PairConnectionType { 235 PairConnectionDirect, 236 PairConnectionSwap, 237 PairConnectionSplat 238 }; 239 240 void computeConnectedPairs( 241 DenseMap<Value *, std::vector<Value *> > &CandidatePairs, 242 DenseSet<ValuePair> &CandidatePairsSet, 243 std::vector<Value *> &PairableInsts, 244 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs, 245 DenseMap<VPPair, unsigned> &PairConnectionTypes); 246 247 void buildDepMap(BasicBlock &BB, 248 DenseMap<Value *, std::vector<Value *> > &CandidatePairs, 249 std::vector<Value *> &PairableInsts, 250 DenseSet<ValuePair> &PairableInstUsers); 251 252 void choosePairs(DenseMap<Value *, std::vector<Value *> > &CandidatePairs, 253 DenseSet<ValuePair> &CandidatePairsSet, 254 DenseMap<ValuePair, int> &CandidatePairCostSavings, 255 std::vector<Value *> &PairableInsts, 256 DenseSet<ValuePair> &FixedOrderPairs, 257 DenseMap<VPPair, unsigned> &PairConnectionTypes, 258 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs, 259 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairDeps, 260 DenseSet<ValuePair> &PairableInstUsers, 261 DenseMap<Value *, Value *>& ChosenPairs); 262 263 void fuseChosenPairs(BasicBlock &BB, 264 std::vector<Value *> &PairableInsts, 265 DenseMap<Value *, Value *>& ChosenPairs, 266 DenseSet<ValuePair> &FixedOrderPairs, 267 DenseMap<VPPair, unsigned> &PairConnectionTypes, 268 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs, 269 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairDeps); 270 271 272 bool isInstVectorizable(Instruction *I, bool &IsSimpleLoadStore); 273 274 bool areInstsCompatible(Instruction *I, Instruction *J, 275 bool IsSimpleLoadStore, bool NonPow2Len, 276 int &CostSavings, int &FixedOrder); 277 278 bool trackUsesOfI(DenseSet<Value *> &Users, 279 AliasSetTracker &WriteSet, Instruction *I, 280 Instruction *J, bool UpdateUsers = true, 281 DenseSet<ValuePair> *LoadMoveSetPairs = 0); 282 283 void computePairsConnectedTo( 284 DenseMap<Value *, std::vector<Value *> > &CandidatePairs, 285 DenseSet<ValuePair> &CandidatePairsSet, 286 std::vector<Value *> &PairableInsts, 287 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs, 288 DenseMap<VPPair, unsigned> &PairConnectionTypes, 289 ValuePair P); 290 291 bool pairsConflict(ValuePair P, ValuePair Q, 292 DenseSet<ValuePair> &PairableInstUsers, 293 DenseMap<ValuePair, std::vector<ValuePair> > 294 *PairableInstUserMap = 0, 295 DenseSet<VPPair> *PairableInstUserPairSet = 0); 296 297 bool pairWillFormCycle(ValuePair P, 298 DenseMap<ValuePair, std::vector<ValuePair> > &PairableInstUsers, 299 DenseSet<ValuePair> &CurrentPairs); 300 301 void pruneDAGFor( 302 DenseMap<Value *, std::vector<Value *> > &CandidatePairs, 303 std::vector<Value *> &PairableInsts, 304 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs, 305 DenseSet<ValuePair> &PairableInstUsers, 306 DenseMap<ValuePair, std::vector<ValuePair> > &PairableInstUserMap, 307 DenseSet<VPPair> &PairableInstUserPairSet, 308 DenseMap<Value *, Value *> &ChosenPairs, 309 DenseMap<ValuePair, size_t> &DAG, 310 DenseSet<ValuePair> &PrunedDAG, ValuePair J, 311 bool UseCycleCheck); 312 313 void buildInitialDAGFor( 314 DenseMap<Value *, std::vector<Value *> > &CandidatePairs, 315 DenseSet<ValuePair> &CandidatePairsSet, 316 std::vector<Value *> &PairableInsts, 317 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs, 318 DenseSet<ValuePair> &PairableInstUsers, 319 DenseMap<Value *, Value *> &ChosenPairs, 320 DenseMap<ValuePair, size_t> &DAG, ValuePair J); 321 322 void findBestDAGFor( 323 DenseMap<Value *, std::vector<Value *> > &CandidatePairs, 324 DenseSet<ValuePair> &CandidatePairsSet, 325 DenseMap<ValuePair, int> &CandidatePairCostSavings, 326 std::vector<Value *> &PairableInsts, 327 DenseSet<ValuePair> &FixedOrderPairs, 328 DenseMap<VPPair, unsigned> &PairConnectionTypes, 329 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs, 330 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairDeps, 331 DenseSet<ValuePair> &PairableInstUsers, 332 DenseMap<ValuePair, std::vector<ValuePair> > &PairableInstUserMap, 333 DenseSet<VPPair> &PairableInstUserPairSet, 334 DenseMap<Value *, Value *> &ChosenPairs, 335 DenseSet<ValuePair> &BestDAG, size_t &BestMaxDepth, 336 int &BestEffSize, Value *II, std::vector<Value *>&JJ, 337 bool UseCycleCheck); 338 339 Value *getReplacementPointerInput(LLVMContext& Context, Instruction *I, 340 Instruction *J, unsigned o); 341 342 void fillNewShuffleMask(LLVMContext& Context, Instruction *J, 343 unsigned MaskOffset, unsigned NumInElem, 344 unsigned NumInElem1, unsigned IdxOffset, 345 std::vector<Constant*> &Mask); 346 347 Value *getReplacementShuffleMask(LLVMContext& Context, Instruction *I, 348 Instruction *J); 349 350 bool expandIEChain(LLVMContext& Context, Instruction *I, Instruction *J, 351 unsigned o, Value *&LOp, unsigned numElemL, 352 Type *ArgTypeL, Type *ArgTypeR, bool IBeforeJ, 353 unsigned IdxOff = 0); 354 355 Value *getReplacementInput(LLVMContext& Context, Instruction *I, 356 Instruction *J, unsigned o, bool IBeforeJ); 357 358 void getReplacementInputsForPair(LLVMContext& Context, Instruction *I, 359 Instruction *J, SmallVector<Value *, 3> &ReplacedOperands, 360 bool IBeforeJ); 361 362 void replaceOutputsOfPair(LLVMContext& Context, Instruction *I, 363 Instruction *J, Instruction *K, 364 Instruction *&InsertionPt, Instruction *&K1, 365 Instruction *&K2); 366 367 void collectPairLoadMoveSet(BasicBlock &BB, 368 DenseMap<Value *, Value *> &ChosenPairs, 369 DenseMap<Value *, std::vector<Value *> > &LoadMoveSet, 370 DenseSet<ValuePair> &LoadMoveSetPairs, 371 Instruction *I); 372 373 void collectLoadMoveSet(BasicBlock &BB, 374 std::vector<Value *> &PairableInsts, 375 DenseMap<Value *, Value *> &ChosenPairs, 376 DenseMap<Value *, std::vector<Value *> > &LoadMoveSet, 377 DenseSet<ValuePair> &LoadMoveSetPairs); 378 379 bool canMoveUsesOfIAfterJ(BasicBlock &BB, 380 DenseSet<ValuePair> &LoadMoveSetPairs, 381 Instruction *I, Instruction *J); 382 383 void moveUsesOfIAfterJ(BasicBlock &BB, 384 DenseSet<ValuePair> &LoadMoveSetPairs, 385 Instruction *&InsertionPt, 386 Instruction *I, Instruction *J); 387 388 void combineMetadata(Instruction *K, const Instruction *J); 389 390 bool vectorizeBB(BasicBlock &BB) { 391 if (!DT->isReachableFromEntry(&BB)) { 392 DEBUG(dbgs() << "BBV: skipping unreachable " << BB.getName() << 393 " in " << BB.getParent()->getName() << "\n"); 394 return false; 395 } 396 397 DEBUG(if (TTI) dbgs() << "BBV: using target information\n"); 398 399 bool changed = false; 400 // Iterate a sufficient number of times to merge types of size 1 bit, 401 // then 2 bits, then 4, etc. up to half of the target vector width of the 402 // target vector register. 403 unsigned n = 1; 404 for (unsigned v = 2; 405 (TTI || v <= Config.VectorBits) && 406 (!Config.MaxIter || n <= Config.MaxIter); 407 v *= 2, ++n) { 408 DEBUG(dbgs() << "BBV: fusing loop #" << n << 409 " for " << BB.getName() << " in " << 410 BB.getParent()->getName() << "...\n"); 411 if (vectorizePairs(BB)) 412 changed = true; 413 else 414 break; 415 } 416 417 if (changed && !Pow2LenOnly) { 418 ++n; 419 for (; !Config.MaxIter || n <= Config.MaxIter; ++n) { 420 DEBUG(dbgs() << "BBV: fusing for non-2^n-length vectors loop #: " << 421 n << " for " << BB.getName() << " in " << 422 BB.getParent()->getName() << "...\n"); 423 if (!vectorizePairs(BB, true)) break; 424 } 425 } 426 427 DEBUG(dbgs() << "BBV: done!\n"); 428 return changed; 429 } 430 431 virtual bool runOnBasicBlock(BasicBlock &BB) { 432 AA = &getAnalysis<AliasAnalysis>(); 433 DT = &getAnalysis<DominatorTree>(); 434 SE = &getAnalysis<ScalarEvolution>(); 435 TD = getAnalysisIfAvailable<DataLayout>(); 436 TTI = IgnoreTargetInfo ? 0 : &getAnalysis<TargetTransformInfo>(); 437 438 return vectorizeBB(BB); 439 } 440 441 virtual void getAnalysisUsage(AnalysisUsage &AU) const { 442 BasicBlockPass::getAnalysisUsage(AU); 443 AU.addRequired<AliasAnalysis>(); 444 AU.addRequired<DominatorTree>(); 445 AU.addRequired<ScalarEvolution>(); 446 AU.addRequired<TargetTransformInfo>(); 447 AU.addPreserved<AliasAnalysis>(); 448 AU.addPreserved<DominatorTree>(); 449 AU.addPreserved<ScalarEvolution>(); 450 AU.setPreservesCFG(); 451 } 452 453 static inline VectorType *getVecTypeForPair(Type *ElemTy, Type *Elem2Ty) { 454 assert(ElemTy->getScalarType() == Elem2Ty->getScalarType() && 455 "Cannot form vector from incompatible scalar types"); 456 Type *STy = ElemTy->getScalarType(); 457 458 unsigned numElem; 459 if (VectorType *VTy = dyn_cast<VectorType>(ElemTy)) { 460 numElem = VTy->getNumElements(); 461 } else { 462 numElem = 1; 463 } 464 465 if (VectorType *VTy = dyn_cast<VectorType>(Elem2Ty)) { 466 numElem += VTy->getNumElements(); 467 } else { 468 numElem += 1; 469 } 470 471 return VectorType::get(STy, numElem); 472 } 473 474 static inline void getInstructionTypes(Instruction *I, 475 Type *&T1, Type *&T2) { 476 if (StoreInst *SI = dyn_cast<StoreInst>(I)) { 477 // For stores, it is the value type, not the pointer type that matters 478 // because the value is what will come from a vector register. 479 480 Value *IVal = SI->getValueOperand(); 481 T1 = IVal->getType(); 482 } else { 483 T1 = I->getType(); 484 } 485 486 if (CastInst *CI = dyn_cast<CastInst>(I)) 487 T2 = CI->getSrcTy(); 488 else 489 T2 = T1; 490 491 if (SelectInst *SI = dyn_cast<SelectInst>(I)) { 492 T2 = SI->getCondition()->getType(); 493 } else if (ShuffleVectorInst *SI = dyn_cast<ShuffleVectorInst>(I)) { 494 T2 = SI->getOperand(0)->getType(); 495 } else if (CmpInst *CI = dyn_cast<CmpInst>(I)) { 496 T2 = CI->getOperand(0)->getType(); 497 } 498 } 499 500 // Returns the weight associated with the provided value. A chain of 501 // candidate pairs has a length given by the sum of the weights of its 502 // members (one weight per pair; the weight of each member of the pair 503 // is assumed to be the same). This length is then compared to the 504 // chain-length threshold to determine if a given chain is significant 505 // enough to be vectorized. The length is also used in comparing 506 // candidate chains where longer chains are considered to be better. 507 // Note: when this function returns 0, the resulting instructions are 508 // not actually fused. 509 inline size_t getDepthFactor(Value *V) { 510 // InsertElement and ExtractElement have a depth factor of zero. This is 511 // for two reasons: First, they cannot be usefully fused. Second, because 512 // the pass generates a lot of these, they can confuse the simple metric 513 // used to compare the dags in the next iteration. Thus, giving them a 514 // weight of zero allows the pass to essentially ignore them in 515 // subsequent iterations when looking for vectorization opportunities 516 // while still tracking dependency chains that flow through those 517 // instructions. 518 if (isa<InsertElementInst>(V) || isa<ExtractElementInst>(V)) 519 return 0; 520 521 // Give a load or store half of the required depth so that load/store 522 // pairs will vectorize. 523 if (!Config.NoMemOpBoost && (isa<LoadInst>(V) || isa<StoreInst>(V))) 524 return Config.ReqChainDepth/2; 525 526 return 1; 527 } 528 529 // Returns the cost of the provided instruction using TTI. 530 // This does not handle loads and stores. 531 unsigned getInstrCost(unsigned Opcode, Type *T1, Type *T2) { 532 switch (Opcode) { 533 default: break; 534 case Instruction::GetElementPtr: 535 // We mark this instruction as zero-cost because scalar GEPs are usually 536 // lowered to the intruction addressing mode. At the moment we don't 537 // generate vector GEPs. 538 return 0; 539 case Instruction::Br: 540 return TTI->getCFInstrCost(Opcode); 541 case Instruction::PHI: 542 return 0; 543 case Instruction::Add: 544 case Instruction::FAdd: 545 case Instruction::Sub: 546 case Instruction::FSub: 547 case Instruction::Mul: 548 case Instruction::FMul: 549 case Instruction::UDiv: 550 case Instruction::SDiv: 551 case Instruction::FDiv: 552 case Instruction::URem: 553 case Instruction::SRem: 554 case Instruction::FRem: 555 case Instruction::Shl: 556 case Instruction::LShr: 557 case Instruction::AShr: 558 case Instruction::And: 559 case Instruction::Or: 560 case Instruction::Xor: 561 return TTI->getArithmeticInstrCost(Opcode, T1); 562 case Instruction::Select: 563 case Instruction::ICmp: 564 case Instruction::FCmp: 565 return TTI->getCmpSelInstrCost(Opcode, T1, T2); 566 case Instruction::ZExt: 567 case Instruction::SExt: 568 case Instruction::FPToUI: 569 case Instruction::FPToSI: 570 case Instruction::FPExt: 571 case Instruction::PtrToInt: 572 case Instruction::IntToPtr: 573 case Instruction::SIToFP: 574 case Instruction::UIToFP: 575 case Instruction::Trunc: 576 case Instruction::FPTrunc: 577 case Instruction::BitCast: 578 case Instruction::ShuffleVector: 579 return TTI->getCastInstrCost(Opcode, T1, T2); 580 } 581 582 return 1; 583 } 584 585 // This determines the relative offset of two loads or stores, returning 586 // true if the offset could be determined to be some constant value. 587 // For example, if OffsetInElmts == 1, then J accesses the memory directly 588 // after I; if OffsetInElmts == -1 then I accesses the memory 589 // directly after J. 590 bool getPairPtrInfo(Instruction *I, Instruction *J, 591 Value *&IPtr, Value *&JPtr, unsigned &IAlignment, unsigned &JAlignment, 592 unsigned &IAddressSpace, unsigned &JAddressSpace, 593 int64_t &OffsetInElmts, bool ComputeOffset = true) { 594 OffsetInElmts = 0; 595 if (LoadInst *LI = dyn_cast<LoadInst>(I)) { 596 LoadInst *LJ = cast<LoadInst>(J); 597 IPtr = LI->getPointerOperand(); 598 JPtr = LJ->getPointerOperand(); 599 IAlignment = LI->getAlignment(); 600 JAlignment = LJ->getAlignment(); 601 IAddressSpace = LI->getPointerAddressSpace(); 602 JAddressSpace = LJ->getPointerAddressSpace(); 603 } else { 604 StoreInst *SI = cast<StoreInst>(I), *SJ = cast<StoreInst>(J); 605 IPtr = SI->getPointerOperand(); 606 JPtr = SJ->getPointerOperand(); 607 IAlignment = SI->getAlignment(); 608 JAlignment = SJ->getAlignment(); 609 IAddressSpace = SI->getPointerAddressSpace(); 610 JAddressSpace = SJ->getPointerAddressSpace(); 611 } 612 613 if (!ComputeOffset) 614 return true; 615 616 const SCEV *IPtrSCEV = SE->getSCEV(IPtr); 617 const SCEV *JPtrSCEV = SE->getSCEV(JPtr); 618 619 // If this is a trivial offset, then we'll get something like 620 // 1*sizeof(type). With target data, which we need anyway, this will get 621 // constant folded into a number. 622 const SCEV *OffsetSCEV = SE->getMinusSCEV(JPtrSCEV, IPtrSCEV); 623 if (const SCEVConstant *ConstOffSCEV = 624 dyn_cast<SCEVConstant>(OffsetSCEV)) { 625 ConstantInt *IntOff = ConstOffSCEV->getValue(); 626 int64_t Offset = IntOff->getSExtValue(); 627 628 Type *VTy = cast<PointerType>(IPtr->getType())->getElementType(); 629 int64_t VTyTSS = (int64_t) TD->getTypeStoreSize(VTy); 630 631 Type *VTy2 = cast<PointerType>(JPtr->getType())->getElementType(); 632 if (VTy != VTy2 && Offset < 0) { 633 int64_t VTy2TSS = (int64_t) TD->getTypeStoreSize(VTy2); 634 OffsetInElmts = Offset/VTy2TSS; 635 return (abs64(Offset) % VTy2TSS) == 0; 636 } 637 638 OffsetInElmts = Offset/VTyTSS; 639 return (abs64(Offset) % VTyTSS) == 0; 640 } 641 642 return false; 643 } 644 645 // Returns true if the provided CallInst represents an intrinsic that can 646 // be vectorized. 647 bool isVectorizableIntrinsic(CallInst* I) { 648 Function *F = I->getCalledFunction(); 649 if (!F) return false; 650 651 Intrinsic::ID IID = (Intrinsic::ID) F->getIntrinsicID(); 652 if (!IID) return false; 653 654 switch(IID) { 655 default: 656 return false; 657 case Intrinsic::sqrt: 658 case Intrinsic::powi: 659 case Intrinsic::sin: 660 case Intrinsic::cos: 661 case Intrinsic::log: 662 case Intrinsic::log2: 663 case Intrinsic::log10: 664 case Intrinsic::exp: 665 case Intrinsic::exp2: 666 case Intrinsic::pow: 667 return Config.VectorizeMath; 668 case Intrinsic::fma: 669 case Intrinsic::fmuladd: 670 return Config.VectorizeFMA; 671 } 672 } 673 674 bool isPureIEChain(InsertElementInst *IE) { 675 InsertElementInst *IENext = IE; 676 do { 677 if (!isa<UndefValue>(IENext->getOperand(0)) && 678 !isa<InsertElementInst>(IENext->getOperand(0))) { 679 return false; 680 } 681 } while ((IENext = 682 dyn_cast<InsertElementInst>(IENext->getOperand(0)))); 683 684 return true; 685 } 686 }; 687 688 // This function implements one vectorization iteration on the provided 689 // basic block. It returns true if the block is changed. 690 bool BBVectorize::vectorizePairs(BasicBlock &BB, bool NonPow2Len) { 691 bool ShouldContinue; 692 BasicBlock::iterator Start = BB.getFirstInsertionPt(); 693 694 std::vector<Value *> AllPairableInsts; 695 DenseMap<Value *, Value *> AllChosenPairs; 696 DenseSet<ValuePair> AllFixedOrderPairs; 697 DenseMap<VPPair, unsigned> AllPairConnectionTypes; 698 DenseMap<ValuePair, std::vector<ValuePair> > AllConnectedPairs, 699 AllConnectedPairDeps; 700 701 do { 702 std::vector<Value *> PairableInsts; 703 DenseMap<Value *, std::vector<Value *> > CandidatePairs; 704 DenseSet<ValuePair> FixedOrderPairs; 705 DenseMap<ValuePair, int> CandidatePairCostSavings; 706 ShouldContinue = getCandidatePairs(BB, Start, CandidatePairs, 707 FixedOrderPairs, 708 CandidatePairCostSavings, 709 PairableInsts, NonPow2Len); 710 if (PairableInsts.empty()) continue; 711 712 // Build the candidate pair set for faster lookups. 713 DenseSet<ValuePair> CandidatePairsSet; 714 for (DenseMap<Value *, std::vector<Value *> >::iterator I = 715 CandidatePairs.begin(), E = CandidatePairs.end(); I != E; ++I) 716 for (std::vector<Value *>::iterator J = I->second.begin(), 717 JE = I->second.end(); J != JE; ++J) 718 CandidatePairsSet.insert(ValuePair(I->first, *J)); 719 720 // Now we have a map of all of the pairable instructions and we need to 721 // select the best possible pairing. A good pairing is one such that the 722 // users of the pair are also paired. This defines a (directed) forest 723 // over the pairs such that two pairs are connected iff the second pair 724 // uses the first. 725 726 // Note that it only matters that both members of the second pair use some 727 // element of the first pair (to allow for splatting). 728 729 DenseMap<ValuePair, std::vector<ValuePair> > ConnectedPairs, 730 ConnectedPairDeps; 731 DenseMap<VPPair, unsigned> PairConnectionTypes; 732 computeConnectedPairs(CandidatePairs, CandidatePairsSet, 733 PairableInsts, ConnectedPairs, PairConnectionTypes); 734 if (ConnectedPairs.empty()) continue; 735 736 for (DenseMap<ValuePair, std::vector<ValuePair> >::iterator 737 I = ConnectedPairs.begin(), IE = ConnectedPairs.end(); 738 I != IE; ++I) 739 for (std::vector<ValuePair>::iterator J = I->second.begin(), 740 JE = I->second.end(); J != JE; ++J) 741 ConnectedPairDeps[*J].push_back(I->first); 742 743 // Build the pairable-instruction dependency map 744 DenseSet<ValuePair> PairableInstUsers; 745 buildDepMap(BB, CandidatePairs, PairableInsts, PairableInstUsers); 746 747 // There is now a graph of the connected pairs. For each variable, pick 748 // the pairing with the largest dag meeting the depth requirement on at 749 // least one branch. Then select all pairings that are part of that dag 750 // and remove them from the list of available pairings and pairable 751 // variables. 752 753 DenseMap<Value *, Value *> ChosenPairs; 754 choosePairs(CandidatePairs, CandidatePairsSet, 755 CandidatePairCostSavings, 756 PairableInsts, FixedOrderPairs, PairConnectionTypes, 757 ConnectedPairs, ConnectedPairDeps, 758 PairableInstUsers, ChosenPairs); 759 760 if (ChosenPairs.empty()) continue; 761 AllPairableInsts.insert(AllPairableInsts.end(), PairableInsts.begin(), 762 PairableInsts.end()); 763 AllChosenPairs.insert(ChosenPairs.begin(), ChosenPairs.end()); 764 765 // Only for the chosen pairs, propagate information on fixed-order pairs, 766 // pair connections, and their types to the data structures used by the 767 // pair fusion procedures. 768 for (DenseMap<Value *, Value *>::iterator I = ChosenPairs.begin(), 769 IE = ChosenPairs.end(); I != IE; ++I) { 770 if (FixedOrderPairs.count(*I)) 771 AllFixedOrderPairs.insert(*I); 772 else if (FixedOrderPairs.count(ValuePair(I->second, I->first))) 773 AllFixedOrderPairs.insert(ValuePair(I->second, I->first)); 774 775 for (DenseMap<Value *, Value *>::iterator J = ChosenPairs.begin(); 776 J != IE; ++J) { 777 DenseMap<VPPair, unsigned>::iterator K = 778 PairConnectionTypes.find(VPPair(*I, *J)); 779 if (K != PairConnectionTypes.end()) { 780 AllPairConnectionTypes.insert(*K); 781 } else { 782 K = PairConnectionTypes.find(VPPair(*J, *I)); 783 if (K != PairConnectionTypes.end()) 784 AllPairConnectionTypes.insert(*K); 785 } 786 } 787 } 788 789 for (DenseMap<ValuePair, std::vector<ValuePair> >::iterator 790 I = ConnectedPairs.begin(), IE = ConnectedPairs.end(); 791 I != IE; ++I) 792 for (std::vector<ValuePair>::iterator J = I->second.begin(), 793 JE = I->second.end(); J != JE; ++J) 794 if (AllPairConnectionTypes.count(VPPair(I->first, *J))) { 795 AllConnectedPairs[I->first].push_back(*J); 796 AllConnectedPairDeps[*J].push_back(I->first); 797 } 798 } while (ShouldContinue); 799 800 if (AllChosenPairs.empty()) return false; 801 NumFusedOps += AllChosenPairs.size(); 802 803 // A set of pairs has now been selected. It is now necessary to replace the 804 // paired instructions with vector instructions. For this procedure each 805 // operand must be replaced with a vector operand. This vector is formed 806 // by using build_vector on the old operands. The replaced values are then 807 // replaced with a vector_extract on the result. Subsequent optimization 808 // passes should coalesce the build/extract combinations. 809 810 fuseChosenPairs(BB, AllPairableInsts, AllChosenPairs, AllFixedOrderPairs, 811 AllPairConnectionTypes, 812 AllConnectedPairs, AllConnectedPairDeps); 813 814 // It is important to cleanup here so that future iterations of this 815 // function have less work to do. 816 (void) SimplifyInstructionsInBlock(&BB, TD, AA->getTargetLibraryInfo()); 817 return true; 818 } 819 820 // This function returns true if the provided instruction is capable of being 821 // fused into a vector instruction. This determination is based only on the 822 // type and other attributes of the instruction. 823 bool BBVectorize::isInstVectorizable(Instruction *I, 824 bool &IsSimpleLoadStore) { 825 IsSimpleLoadStore = false; 826 827 if (CallInst *C = dyn_cast<CallInst>(I)) { 828 if (!isVectorizableIntrinsic(C)) 829 return false; 830 } else if (LoadInst *L = dyn_cast<LoadInst>(I)) { 831 // Vectorize simple loads if possbile: 832 IsSimpleLoadStore = L->isSimple(); 833 if (!IsSimpleLoadStore || !Config.VectorizeMemOps) 834 return false; 835 } else if (StoreInst *S = dyn_cast<StoreInst>(I)) { 836 // Vectorize simple stores if possbile: 837 IsSimpleLoadStore = S->isSimple(); 838 if (!IsSimpleLoadStore || !Config.VectorizeMemOps) 839 return false; 840 } else if (CastInst *C = dyn_cast<CastInst>(I)) { 841 // We can vectorize casts, but not casts of pointer types, etc. 842 if (!Config.VectorizeCasts) 843 return false; 844 845 Type *SrcTy = C->getSrcTy(); 846 if (!SrcTy->isSingleValueType()) 847 return false; 848 849 Type *DestTy = C->getDestTy(); 850 if (!DestTy->isSingleValueType()) 851 return false; 852 } else if (isa<SelectInst>(I)) { 853 if (!Config.VectorizeSelect) 854 return false; 855 } else if (isa<CmpInst>(I)) { 856 if (!Config.VectorizeCmp) 857 return false; 858 } else if (GetElementPtrInst *G = dyn_cast<GetElementPtrInst>(I)) { 859 if (!Config.VectorizeGEP) 860 return false; 861 862 // Currently, vector GEPs exist only with one index. 863 if (G->getNumIndices() != 1) 864 return false; 865 } else if (!(I->isBinaryOp() || isa<ShuffleVectorInst>(I) || 866 isa<ExtractElementInst>(I) || isa<InsertElementInst>(I))) { 867 return false; 868 } 869 870 // We can't vectorize memory operations without target data 871 if (TD == 0 && IsSimpleLoadStore) 872 return false; 873 874 Type *T1, *T2; 875 getInstructionTypes(I, T1, T2); 876 877 // Not every type can be vectorized... 878 if (!(VectorType::isValidElementType(T1) || T1->isVectorTy()) || 879 !(VectorType::isValidElementType(T2) || T2->isVectorTy())) 880 return false; 881 882 if (T1->getScalarSizeInBits() == 1) { 883 if (!Config.VectorizeBools) 884 return false; 885 } else { 886 if (!Config.VectorizeInts && T1->isIntOrIntVectorTy()) 887 return false; 888 } 889 890 if (T2->getScalarSizeInBits() == 1) { 891 if (!Config.VectorizeBools) 892 return false; 893 } else { 894 if (!Config.VectorizeInts && T2->isIntOrIntVectorTy()) 895 return false; 896 } 897 898 if (!Config.VectorizeFloats 899 && (T1->isFPOrFPVectorTy() || T2->isFPOrFPVectorTy())) 900 return false; 901 902 // Don't vectorize target-specific types. 903 if (T1->isX86_FP80Ty() || T1->isPPC_FP128Ty() || T1->isX86_MMXTy()) 904 return false; 905 if (T2->isX86_FP80Ty() || T2->isPPC_FP128Ty() || T2->isX86_MMXTy()) 906 return false; 907 908 if ((!Config.VectorizePointers || TD == 0) && 909 (T1->getScalarType()->isPointerTy() || 910 T2->getScalarType()->isPointerTy())) 911 return false; 912 913 if (!TTI && (T1->getPrimitiveSizeInBits() >= Config.VectorBits || 914 T2->getPrimitiveSizeInBits() >= Config.VectorBits)) 915 return false; 916 917 return true; 918 } 919 920 // This function returns true if the two provided instructions are compatible 921 // (meaning that they can be fused into a vector instruction). This assumes 922 // that I has already been determined to be vectorizable and that J is not 923 // in the use dag of I. 924 bool BBVectorize::areInstsCompatible(Instruction *I, Instruction *J, 925 bool IsSimpleLoadStore, bool NonPow2Len, 926 int &CostSavings, int &FixedOrder) { 927 DEBUG(if (DebugInstructionExamination) dbgs() << "BBV: looking at " << *I << 928 " <-> " << *J << "\n"); 929 930 CostSavings = 0; 931 FixedOrder = 0; 932 933 // Loads and stores can be merged if they have different alignments, 934 // but are otherwise the same. 935 if (!J->isSameOperationAs(I, Instruction::CompareIgnoringAlignment | 936 (NonPow2Len ? Instruction::CompareUsingScalarTypes : 0))) 937 return false; 938 939 Type *IT1, *IT2, *JT1, *JT2; 940 getInstructionTypes(I, IT1, IT2); 941 getInstructionTypes(J, JT1, JT2); 942 unsigned MaxTypeBits = std::max( 943 IT1->getPrimitiveSizeInBits() + JT1->getPrimitiveSizeInBits(), 944 IT2->getPrimitiveSizeInBits() + JT2->getPrimitiveSizeInBits()); 945 if (!TTI && MaxTypeBits > Config.VectorBits) 946 return false; 947 948 // FIXME: handle addsub-type operations! 949 950 if (IsSimpleLoadStore) { 951 Value *IPtr, *JPtr; 952 unsigned IAlignment, JAlignment, IAddressSpace, JAddressSpace; 953 int64_t OffsetInElmts = 0; 954 if (getPairPtrInfo(I, J, IPtr, JPtr, IAlignment, JAlignment, 955 IAddressSpace, JAddressSpace, 956 OffsetInElmts) && abs64(OffsetInElmts) == 1) { 957 FixedOrder = (int) OffsetInElmts; 958 unsigned BottomAlignment = IAlignment; 959 if (OffsetInElmts < 0) BottomAlignment = JAlignment; 960 961 Type *aTypeI = isa<StoreInst>(I) ? 962 cast<StoreInst>(I)->getValueOperand()->getType() : I->getType(); 963 Type *aTypeJ = isa<StoreInst>(J) ? 964 cast<StoreInst>(J)->getValueOperand()->getType() : J->getType(); 965 Type *VType = getVecTypeForPair(aTypeI, aTypeJ); 966 967 if (Config.AlignedOnly) { 968 // An aligned load or store is possible only if the instruction 969 // with the lower offset has an alignment suitable for the 970 // vector type. 971 972 unsigned VecAlignment = TD->getPrefTypeAlignment(VType); 973 if (BottomAlignment < VecAlignment) 974 return false; 975 } 976 977 if (TTI) { 978 unsigned ICost = TTI->getMemoryOpCost(I->getOpcode(), aTypeI, 979 IAlignment, IAddressSpace); 980 unsigned JCost = TTI->getMemoryOpCost(J->getOpcode(), aTypeJ, 981 JAlignment, JAddressSpace); 982 unsigned VCost = TTI->getMemoryOpCost(I->getOpcode(), VType, 983 BottomAlignment, 984 IAddressSpace); 985 986 ICost += TTI->getAddressComputationCost(aTypeI); 987 JCost += TTI->getAddressComputationCost(aTypeJ); 988 VCost += TTI->getAddressComputationCost(VType); 989 990 if (VCost > ICost + JCost) 991 return false; 992 993 // We don't want to fuse to a type that will be split, even 994 // if the two input types will also be split and there is no other 995 // associated cost. 996 unsigned VParts = TTI->getNumberOfParts(VType); 997 if (VParts > 1) 998 return false; 999 else if (!VParts && VCost == ICost + JCost) 1000 return false; 1001 1002 CostSavings = ICost + JCost - VCost; 1003 } 1004 } else { 1005 return false; 1006 } 1007 } else if (TTI) { 1008 unsigned ICost = getInstrCost(I->getOpcode(), IT1, IT2); 1009 unsigned JCost = getInstrCost(J->getOpcode(), JT1, JT2); 1010 Type *VT1 = getVecTypeForPair(IT1, JT1), 1011 *VT2 = getVecTypeForPair(IT2, JT2); 1012 1013 // Note that this procedure is incorrect for insert and extract element 1014 // instructions (because combining these often results in a shuffle), 1015 // but this cost is ignored (because insert and extract element 1016 // instructions are assigned a zero depth factor and are not really 1017 // fused in general). 1018 unsigned VCost = getInstrCost(I->getOpcode(), VT1, VT2); 1019 1020 if (VCost > ICost + JCost) 1021 return false; 1022 1023 // We don't want to fuse to a type that will be split, even 1024 // if the two input types will also be split and there is no other 1025 // associated cost. 1026 unsigned VParts1 = TTI->getNumberOfParts(VT1), 1027 VParts2 = TTI->getNumberOfParts(VT2); 1028 if (VParts1 > 1 || VParts2 > 1) 1029 return false; 1030 else if ((!VParts1 || !VParts2) && VCost == ICost + JCost) 1031 return false; 1032 1033 CostSavings = ICost + JCost - VCost; 1034 } 1035 1036 // The powi intrinsic is special because only the first argument is 1037 // vectorized, the second arguments must be equal. 1038 CallInst *CI = dyn_cast<CallInst>(I); 1039 Function *FI; 1040 if (CI && (FI = CI->getCalledFunction())) { 1041 Intrinsic::ID IID = (Intrinsic::ID) FI->getIntrinsicID(); 1042 if (IID == Intrinsic::powi) { 1043 Value *A1I = CI->getArgOperand(1), 1044 *A1J = cast<CallInst>(J)->getArgOperand(1); 1045 const SCEV *A1ISCEV = SE->getSCEV(A1I), 1046 *A1JSCEV = SE->getSCEV(A1J); 1047 return (A1ISCEV == A1JSCEV); 1048 } 1049 1050 if (IID && TTI) { 1051 SmallVector<Type*, 4> Tys; 1052 for (unsigned i = 0, ie = CI->getNumArgOperands(); i != ie; ++i) 1053 Tys.push_back(CI->getArgOperand(i)->getType()); 1054 unsigned ICost = TTI->getIntrinsicInstrCost(IID, IT1, Tys); 1055 1056 Tys.clear(); 1057 CallInst *CJ = cast<CallInst>(J); 1058 for (unsigned i = 0, ie = CJ->getNumArgOperands(); i != ie; ++i) 1059 Tys.push_back(CJ->getArgOperand(i)->getType()); 1060 unsigned JCost = TTI->getIntrinsicInstrCost(IID, JT1, Tys); 1061 1062 Tys.clear(); 1063 assert(CI->getNumArgOperands() == CJ->getNumArgOperands() && 1064 "Intrinsic argument counts differ"); 1065 for (unsigned i = 0, ie = CI->getNumArgOperands(); i != ie; ++i) { 1066 if (IID == Intrinsic::powi && i == 1) 1067 Tys.push_back(CI->getArgOperand(i)->getType()); 1068 else 1069 Tys.push_back(getVecTypeForPair(CI->getArgOperand(i)->getType(), 1070 CJ->getArgOperand(i)->getType())); 1071 } 1072 1073 Type *RetTy = getVecTypeForPair(IT1, JT1); 1074 unsigned VCost = TTI->getIntrinsicInstrCost(IID, RetTy, Tys); 1075 1076 if (VCost > ICost + JCost) 1077 return false; 1078 1079 // We don't want to fuse to a type that will be split, even 1080 // if the two input types will also be split and there is no other 1081 // associated cost. 1082 unsigned RetParts = TTI->getNumberOfParts(RetTy); 1083 if (RetParts > 1) 1084 return false; 1085 else if (!RetParts && VCost == ICost + JCost) 1086 return false; 1087 1088 for (unsigned i = 0, ie = CI->getNumArgOperands(); i != ie; ++i) { 1089 if (!Tys[i]->isVectorTy()) 1090 continue; 1091 1092 unsigned NumParts = TTI->getNumberOfParts(Tys[i]); 1093 if (NumParts > 1) 1094 return false; 1095 else if (!NumParts && VCost == ICost + JCost) 1096 return false; 1097 } 1098 1099 CostSavings = ICost + JCost - VCost; 1100 } 1101 } 1102 1103 return true; 1104 } 1105 1106 // Figure out whether or not J uses I and update the users and write-set 1107 // structures associated with I. Specifically, Users represents the set of 1108 // instructions that depend on I. WriteSet represents the set 1109 // of memory locations that are dependent on I. If UpdateUsers is true, 1110 // and J uses I, then Users is updated to contain J and WriteSet is updated 1111 // to contain any memory locations to which J writes. The function returns 1112 // true if J uses I. By default, alias analysis is used to determine 1113 // whether J reads from memory that overlaps with a location in WriteSet. 1114 // If LoadMoveSet is not null, then it is a previously-computed map 1115 // where the key is the memory-based user instruction and the value is 1116 // the instruction to be compared with I. So, if LoadMoveSet is provided, 1117 // then the alias analysis is not used. This is necessary because this 1118 // function is called during the process of moving instructions during 1119 // vectorization and the results of the alias analysis are not stable during 1120 // that process. 1121 bool BBVectorize::trackUsesOfI(DenseSet<Value *> &Users, 1122 AliasSetTracker &WriteSet, Instruction *I, 1123 Instruction *J, bool UpdateUsers, 1124 DenseSet<ValuePair> *LoadMoveSetPairs) { 1125 bool UsesI = false; 1126 1127 // This instruction may already be marked as a user due, for example, to 1128 // being a member of a selected pair. 1129 if (Users.count(J)) 1130 UsesI = true; 1131 1132 if (!UsesI) 1133 for (User::op_iterator JU = J->op_begin(), JE = J->op_end(); 1134 JU != JE; ++JU) { 1135 Value *V = *JU; 1136 if (I == V || Users.count(V)) { 1137 UsesI = true; 1138 break; 1139 } 1140 } 1141 if (!UsesI && J->mayReadFromMemory()) { 1142 if (LoadMoveSetPairs) { 1143 UsesI = LoadMoveSetPairs->count(ValuePair(J, I)); 1144 } else { 1145 for (AliasSetTracker::iterator W = WriteSet.begin(), 1146 WE = WriteSet.end(); W != WE; ++W) { 1147 if (W->aliasesUnknownInst(J, *AA)) { 1148 UsesI = true; 1149 break; 1150 } 1151 } 1152 } 1153 } 1154 1155 if (UsesI && UpdateUsers) { 1156 if (J->mayWriteToMemory()) WriteSet.add(J); 1157 Users.insert(J); 1158 } 1159 1160 return UsesI; 1161 } 1162 1163 // This function iterates over all instruction pairs in the provided 1164 // basic block and collects all candidate pairs for vectorization. 1165 bool BBVectorize::getCandidatePairs(BasicBlock &BB, 1166 BasicBlock::iterator &Start, 1167 DenseMap<Value *, std::vector<Value *> > &CandidatePairs, 1168 DenseSet<ValuePair> &FixedOrderPairs, 1169 DenseMap<ValuePair, int> &CandidatePairCostSavings, 1170 std::vector<Value *> &PairableInsts, bool NonPow2Len) { 1171 size_t TotalPairs = 0; 1172 BasicBlock::iterator E = BB.end(); 1173 if (Start == E) return false; 1174 1175 bool ShouldContinue = false, IAfterStart = false; 1176 for (BasicBlock::iterator I = Start++; I != E; ++I) { 1177 if (I == Start) IAfterStart = true; 1178 1179 bool IsSimpleLoadStore; 1180 if (!isInstVectorizable(I, IsSimpleLoadStore)) continue; 1181 1182 // Look for an instruction with which to pair instruction *I... 1183 DenseSet<Value *> Users; 1184 AliasSetTracker WriteSet(*AA); 1185 bool JAfterStart = IAfterStart; 1186 BasicBlock::iterator J = llvm::next(I); 1187 for (unsigned ss = 0; J != E && ss <= Config.SearchLimit; ++J, ++ss) { 1188 if (J == Start) JAfterStart = true; 1189 1190 // Determine if J uses I, if so, exit the loop. 1191 bool UsesI = trackUsesOfI(Users, WriteSet, I, J, !Config.FastDep); 1192 if (Config.FastDep) { 1193 // Note: For this heuristic to be effective, independent operations 1194 // must tend to be intermixed. This is likely to be true from some 1195 // kinds of grouped loop unrolling (but not the generic LLVM pass), 1196 // but otherwise may require some kind of reordering pass. 1197 1198 // When using fast dependency analysis, 1199 // stop searching after first use: 1200 if (UsesI) break; 1201 } else { 1202 if (UsesI) continue; 1203 } 1204 1205 // J does not use I, and comes before the first use of I, so it can be 1206 // merged with I if the instructions are compatible. 1207 int CostSavings, FixedOrder; 1208 if (!areInstsCompatible(I, J, IsSimpleLoadStore, NonPow2Len, 1209 CostSavings, FixedOrder)) continue; 1210 1211 // J is a candidate for merging with I. 1212 if (!PairableInsts.size() || 1213 PairableInsts[PairableInsts.size()-1] != I) { 1214 PairableInsts.push_back(I); 1215 } 1216 1217 CandidatePairs[I].push_back(J); 1218 ++TotalPairs; 1219 if (TTI) 1220 CandidatePairCostSavings.insert(ValuePairWithCost(ValuePair(I, J), 1221 CostSavings)); 1222 1223 if (FixedOrder == 1) 1224 FixedOrderPairs.insert(ValuePair(I, J)); 1225 else if (FixedOrder == -1) 1226 FixedOrderPairs.insert(ValuePair(J, I)); 1227 1228 // The next call to this function must start after the last instruction 1229 // selected during this invocation. 1230 if (JAfterStart) { 1231 Start = llvm::next(J); 1232 IAfterStart = JAfterStart = false; 1233 } 1234 1235 DEBUG(if (DebugCandidateSelection) dbgs() << "BBV: candidate pair " 1236 << *I << " <-> " << *J << " (cost savings: " << 1237 CostSavings << ")\n"); 1238 1239 // If we have already found too many pairs, break here and this function 1240 // will be called again starting after the last instruction selected 1241 // during this invocation. 1242 if (PairableInsts.size() >= Config.MaxInsts || 1243 TotalPairs >= Config.MaxPairs) { 1244 ShouldContinue = true; 1245 break; 1246 } 1247 } 1248 1249 if (ShouldContinue) 1250 break; 1251 } 1252 1253 DEBUG(dbgs() << "BBV: found " << PairableInsts.size() 1254 << " instructions with candidate pairs\n"); 1255 1256 return ShouldContinue; 1257 } 1258 1259 // Finds candidate pairs connected to the pair P = <PI, PJ>. This means that 1260 // it looks for pairs such that both members have an input which is an 1261 // output of PI or PJ. 1262 void BBVectorize::computePairsConnectedTo( 1263 DenseMap<Value *, std::vector<Value *> > &CandidatePairs, 1264 DenseSet<ValuePair> &CandidatePairsSet, 1265 std::vector<Value *> &PairableInsts, 1266 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs, 1267 DenseMap<VPPair, unsigned> &PairConnectionTypes, 1268 ValuePair P) { 1269 StoreInst *SI, *SJ; 1270 1271 // For each possible pairing for this variable, look at the uses of 1272 // the first value... 1273 for (Value::use_iterator I = P.first->use_begin(), 1274 E = P.first->use_end(); I != E; ++I) { 1275 if (isa<LoadInst>(*I)) { 1276 // A pair cannot be connected to a load because the load only takes one 1277 // operand (the address) and it is a scalar even after vectorization. 1278 continue; 1279 } else if ((SI = dyn_cast<StoreInst>(*I)) && 1280 P.first == SI->getPointerOperand()) { 1281 // Similarly, a pair cannot be connected to a store through its 1282 // pointer operand. 1283 continue; 1284 } 1285 1286 // For each use of the first variable, look for uses of the second 1287 // variable... 1288 for (Value::use_iterator J = P.second->use_begin(), 1289 E2 = P.second->use_end(); J != E2; ++J) { 1290 if ((SJ = dyn_cast<StoreInst>(*J)) && 1291 P.second == SJ->getPointerOperand()) 1292 continue; 1293 1294 // Look for <I, J>: 1295 if (CandidatePairsSet.count(ValuePair(*I, *J))) { 1296 VPPair VP(P, ValuePair(*I, *J)); 1297 ConnectedPairs[VP.first].push_back(VP.second); 1298 PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionDirect)); 1299 } 1300 1301 // Look for <J, I>: 1302 if (CandidatePairsSet.count(ValuePair(*J, *I))) { 1303 VPPair VP(P, ValuePair(*J, *I)); 1304 ConnectedPairs[VP.first].push_back(VP.second); 1305 PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionSwap)); 1306 } 1307 } 1308 1309 if (Config.SplatBreaksChain) continue; 1310 // Look for cases where just the first value in the pair is used by 1311 // both members of another pair (splatting). 1312 for (Value::use_iterator J = P.first->use_begin(); J != E; ++J) { 1313 if ((SJ = dyn_cast<StoreInst>(*J)) && 1314 P.first == SJ->getPointerOperand()) 1315 continue; 1316 1317 if (CandidatePairsSet.count(ValuePair(*I, *J))) { 1318 VPPair VP(P, ValuePair(*I, *J)); 1319 ConnectedPairs[VP.first].push_back(VP.second); 1320 PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionSplat)); 1321 } 1322 } 1323 } 1324 1325 if (Config.SplatBreaksChain) return; 1326 // Look for cases where just the second value in the pair is used by 1327 // both members of another pair (splatting). 1328 for (Value::use_iterator I = P.second->use_begin(), 1329 E = P.second->use_end(); I != E; ++I) { 1330 if (isa<LoadInst>(*I)) 1331 continue; 1332 else if ((SI = dyn_cast<StoreInst>(*I)) && 1333 P.second == SI->getPointerOperand()) 1334 continue; 1335 1336 for (Value::use_iterator J = P.second->use_begin(); J != E; ++J) { 1337 if ((SJ = dyn_cast<StoreInst>(*J)) && 1338 P.second == SJ->getPointerOperand()) 1339 continue; 1340 1341 if (CandidatePairsSet.count(ValuePair(*I, *J))) { 1342 VPPair VP(P, ValuePair(*I, *J)); 1343 ConnectedPairs[VP.first].push_back(VP.second); 1344 PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionSplat)); 1345 } 1346 } 1347 } 1348 } 1349 1350 // This function figures out which pairs are connected. Two pairs are 1351 // connected if some output of the first pair forms an input to both members 1352 // of the second pair. 1353 void BBVectorize::computeConnectedPairs( 1354 DenseMap<Value *, std::vector<Value *> > &CandidatePairs, 1355 DenseSet<ValuePair> &CandidatePairsSet, 1356 std::vector<Value *> &PairableInsts, 1357 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs, 1358 DenseMap<VPPair, unsigned> &PairConnectionTypes) { 1359 for (std::vector<Value *>::iterator PI = PairableInsts.begin(), 1360 PE = PairableInsts.end(); PI != PE; ++PI) { 1361 DenseMap<Value *, std::vector<Value *> >::iterator PP = 1362 CandidatePairs.find(*PI); 1363 if (PP == CandidatePairs.end()) 1364 continue; 1365 1366 for (std::vector<Value *>::iterator P = PP->second.begin(), 1367 E = PP->second.end(); P != E; ++P) 1368 computePairsConnectedTo(CandidatePairs, CandidatePairsSet, 1369 PairableInsts, ConnectedPairs, 1370 PairConnectionTypes, ValuePair(*PI, *P)); 1371 } 1372 1373 DEBUG(size_t TotalPairs = 0; 1374 for (DenseMap<ValuePair, std::vector<ValuePair> >::iterator I = 1375 ConnectedPairs.begin(), IE = ConnectedPairs.end(); I != IE; ++I) 1376 TotalPairs += I->second.size(); 1377 dbgs() << "BBV: found " << TotalPairs 1378 << " pair connections.\n"); 1379 } 1380 1381 // This function builds a set of use tuples such that <A, B> is in the set 1382 // if B is in the use dag of A. If B is in the use dag of A, then B 1383 // depends on the output of A. 1384 void BBVectorize::buildDepMap( 1385 BasicBlock &BB, 1386 DenseMap<Value *, std::vector<Value *> > &CandidatePairs, 1387 std::vector<Value *> &PairableInsts, 1388 DenseSet<ValuePair> &PairableInstUsers) { 1389 DenseSet<Value *> IsInPair; 1390 for (DenseMap<Value *, std::vector<Value *> >::iterator C = 1391 CandidatePairs.begin(), E = CandidatePairs.end(); C != E; ++C) { 1392 IsInPair.insert(C->first); 1393 IsInPair.insert(C->second.begin(), C->second.end()); 1394 } 1395 1396 // Iterate through the basic block, recording all users of each 1397 // pairable instruction. 1398 1399 BasicBlock::iterator E = BB.end(), EL = 1400 BasicBlock::iterator(cast<Instruction>(PairableInsts.back())); 1401 for (BasicBlock::iterator I = BB.getFirstInsertionPt(); I != E; ++I) { 1402 if (IsInPair.find(I) == IsInPair.end()) continue; 1403 1404 DenseSet<Value *> Users; 1405 AliasSetTracker WriteSet(*AA); 1406 for (BasicBlock::iterator J = llvm::next(I); J != E; ++J) { 1407 (void) trackUsesOfI(Users, WriteSet, I, J); 1408 1409 if (J == EL) 1410 break; 1411 } 1412 1413 for (DenseSet<Value *>::iterator U = Users.begin(), E = Users.end(); 1414 U != E; ++U) { 1415 if (IsInPair.find(*U) == IsInPair.end()) continue; 1416 PairableInstUsers.insert(ValuePair(I, *U)); 1417 } 1418 1419 if (I == EL) 1420 break; 1421 } 1422 } 1423 1424 // Returns true if an input to pair P is an output of pair Q and also an 1425 // input of pair Q is an output of pair P. If this is the case, then these 1426 // two pairs cannot be simultaneously fused. 1427 bool BBVectorize::pairsConflict(ValuePair P, ValuePair Q, 1428 DenseSet<ValuePair> &PairableInstUsers, 1429 DenseMap<ValuePair, std::vector<ValuePair> > *PairableInstUserMap, 1430 DenseSet<VPPair> *PairableInstUserPairSet) { 1431 // Two pairs are in conflict if they are mutual Users of eachother. 1432 bool QUsesP = PairableInstUsers.count(ValuePair(P.first, Q.first)) || 1433 PairableInstUsers.count(ValuePair(P.first, Q.second)) || 1434 PairableInstUsers.count(ValuePair(P.second, Q.first)) || 1435 PairableInstUsers.count(ValuePair(P.second, Q.second)); 1436 bool PUsesQ = PairableInstUsers.count(ValuePair(Q.first, P.first)) || 1437 PairableInstUsers.count(ValuePair(Q.first, P.second)) || 1438 PairableInstUsers.count(ValuePair(Q.second, P.first)) || 1439 PairableInstUsers.count(ValuePair(Q.second, P.second)); 1440 if (PairableInstUserMap) { 1441 // FIXME: The expensive part of the cycle check is not so much the cycle 1442 // check itself but this edge insertion procedure. This needs some 1443 // profiling and probably a different data structure. 1444 if (PUsesQ) { 1445 if (PairableInstUserPairSet->insert(VPPair(Q, P)).second) 1446 (*PairableInstUserMap)[Q].push_back(P); 1447 } 1448 if (QUsesP) { 1449 if (PairableInstUserPairSet->insert(VPPair(P, Q)).second) 1450 (*PairableInstUserMap)[P].push_back(Q); 1451 } 1452 } 1453 1454 return (QUsesP && PUsesQ); 1455 } 1456 1457 // This function walks the use graph of current pairs to see if, starting 1458 // from P, the walk returns to P. 1459 bool BBVectorize::pairWillFormCycle(ValuePair P, 1460 DenseMap<ValuePair, std::vector<ValuePair> > &PairableInstUserMap, 1461 DenseSet<ValuePair> &CurrentPairs) { 1462 DEBUG(if (DebugCycleCheck) 1463 dbgs() << "BBV: starting cycle check for : " << *P.first << " <-> " 1464 << *P.second << "\n"); 1465 // A lookup table of visisted pairs is kept because the PairableInstUserMap 1466 // contains non-direct associations. 1467 DenseSet<ValuePair> Visited; 1468 SmallVector<ValuePair, 32> Q; 1469 // General depth-first post-order traversal: 1470 Q.push_back(P); 1471 do { 1472 ValuePair QTop = Q.pop_back_val(); 1473 Visited.insert(QTop); 1474 1475 DEBUG(if (DebugCycleCheck) 1476 dbgs() << "BBV: cycle check visiting: " << *QTop.first << " <-> " 1477 << *QTop.second << "\n"); 1478 DenseMap<ValuePair, std::vector<ValuePair> >::iterator QQ = 1479 PairableInstUserMap.find(QTop); 1480 if (QQ == PairableInstUserMap.end()) 1481 continue; 1482 1483 for (std::vector<ValuePair>::iterator C = QQ->second.begin(), 1484 CE = QQ->second.end(); C != CE; ++C) { 1485 if (*C == P) { 1486 DEBUG(dbgs() 1487 << "BBV: rejected to prevent non-trivial cycle formation: " 1488 << QTop.first << " <-> " << C->second << "\n"); 1489 return true; 1490 } 1491 1492 if (CurrentPairs.count(*C) && !Visited.count(*C)) 1493 Q.push_back(*C); 1494 } 1495 } while (!Q.empty()); 1496 1497 return false; 1498 } 1499 1500 // This function builds the initial dag of connected pairs with the 1501 // pair J at the root. 1502 void BBVectorize::buildInitialDAGFor( 1503 DenseMap<Value *, std::vector<Value *> > &CandidatePairs, 1504 DenseSet<ValuePair> &CandidatePairsSet, 1505 std::vector<Value *> &PairableInsts, 1506 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs, 1507 DenseSet<ValuePair> &PairableInstUsers, 1508 DenseMap<Value *, Value *> &ChosenPairs, 1509 DenseMap<ValuePair, size_t> &DAG, ValuePair J) { 1510 // Each of these pairs is viewed as the root node of a DAG. The DAG 1511 // is then walked (depth-first). As this happens, we keep track of 1512 // the pairs that compose the DAG and the maximum depth of the DAG. 1513 SmallVector<ValuePairWithDepth, 32> Q; 1514 // General depth-first post-order traversal: 1515 Q.push_back(ValuePairWithDepth(J, getDepthFactor(J.first))); 1516 do { 1517 ValuePairWithDepth QTop = Q.back(); 1518 1519 // Push each child onto the queue: 1520 bool MoreChildren = false; 1521 size_t MaxChildDepth = QTop.second; 1522 DenseMap<ValuePair, std::vector<ValuePair> >::iterator QQ = 1523 ConnectedPairs.find(QTop.first); 1524 if (QQ != ConnectedPairs.end()) 1525 for (std::vector<ValuePair>::iterator k = QQ->second.begin(), 1526 ke = QQ->second.end(); k != ke; ++k) { 1527 // Make sure that this child pair is still a candidate: 1528 if (CandidatePairsSet.count(*k)) { 1529 DenseMap<ValuePair, size_t>::iterator C = DAG.find(*k); 1530 if (C == DAG.end()) { 1531 size_t d = getDepthFactor(k->first); 1532 Q.push_back(ValuePairWithDepth(*k, QTop.second+d)); 1533 MoreChildren = true; 1534 } else { 1535 MaxChildDepth = std::max(MaxChildDepth, C->second); 1536 } 1537 } 1538 } 1539 1540 if (!MoreChildren) { 1541 // Record the current pair as part of the DAG: 1542 DAG.insert(ValuePairWithDepth(QTop.first, MaxChildDepth)); 1543 Q.pop_back(); 1544 } 1545 } while (!Q.empty()); 1546 } 1547 1548 // Given some initial dag, prune it by removing conflicting pairs (pairs 1549 // that cannot be simultaneously chosen for vectorization). 1550 void BBVectorize::pruneDAGFor( 1551 DenseMap<Value *, std::vector<Value *> > &CandidatePairs, 1552 std::vector<Value *> &PairableInsts, 1553 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs, 1554 DenseSet<ValuePair> &PairableInstUsers, 1555 DenseMap<ValuePair, std::vector<ValuePair> > &PairableInstUserMap, 1556 DenseSet<VPPair> &PairableInstUserPairSet, 1557 DenseMap<Value *, Value *> &ChosenPairs, 1558 DenseMap<ValuePair, size_t> &DAG, 1559 DenseSet<ValuePair> &PrunedDAG, ValuePair J, 1560 bool UseCycleCheck) { 1561 SmallVector<ValuePairWithDepth, 32> Q; 1562 // General depth-first post-order traversal: 1563 Q.push_back(ValuePairWithDepth(J, getDepthFactor(J.first))); 1564 do { 1565 ValuePairWithDepth QTop = Q.pop_back_val(); 1566 PrunedDAG.insert(QTop.first); 1567 1568 // Visit each child, pruning as necessary... 1569 SmallVector<ValuePairWithDepth, 8> BestChildren; 1570 DenseMap<ValuePair, std::vector<ValuePair> >::iterator QQ = 1571 ConnectedPairs.find(QTop.first); 1572 if (QQ == ConnectedPairs.end()) 1573 continue; 1574 1575 for (std::vector<ValuePair>::iterator K = QQ->second.begin(), 1576 KE = QQ->second.end(); K != KE; ++K) { 1577 DenseMap<ValuePair, size_t>::iterator C = DAG.find(*K); 1578 if (C == DAG.end()) continue; 1579 1580 // This child is in the DAG, now we need to make sure it is the 1581 // best of any conflicting children. There could be multiple 1582 // conflicting children, so first, determine if we're keeping 1583 // this child, then delete conflicting children as necessary. 1584 1585 // It is also necessary to guard against pairing-induced 1586 // dependencies. Consider instructions a .. x .. y .. b 1587 // such that (a,b) are to be fused and (x,y) are to be fused 1588 // but a is an input to x and b is an output from y. This 1589 // means that y cannot be moved after b but x must be moved 1590 // after b for (a,b) to be fused. In other words, after 1591 // fusing (a,b) we have y .. a/b .. x where y is an input 1592 // to a/b and x is an output to a/b: x and y can no longer 1593 // be legally fused. To prevent this condition, we must 1594 // make sure that a child pair added to the DAG is not 1595 // both an input and output of an already-selected pair. 1596 1597 // Pairing-induced dependencies can also form from more complicated 1598 // cycles. The pair vs. pair conflicts are easy to check, and so 1599 // that is done explicitly for "fast rejection", and because for 1600 // child vs. child conflicts, we may prefer to keep the current 1601 // pair in preference to the already-selected child. 1602 DenseSet<ValuePair> CurrentPairs; 1603 1604 bool CanAdd = true; 1605 for (SmallVector<ValuePairWithDepth, 8>::iterator C2 1606 = BestChildren.begin(), E2 = BestChildren.end(); 1607 C2 != E2; ++C2) { 1608 if (C2->first.first == C->first.first || 1609 C2->first.first == C->first.second || 1610 C2->first.second == C->first.first || 1611 C2->first.second == C->first.second || 1612 pairsConflict(C2->first, C->first, PairableInstUsers, 1613 UseCycleCheck ? &PairableInstUserMap : 0, 1614 UseCycleCheck ? &PairableInstUserPairSet : 0)) { 1615 if (C2->second >= C->second) { 1616 CanAdd = false; 1617 break; 1618 } 1619 1620 CurrentPairs.insert(C2->first); 1621 } 1622 } 1623 if (!CanAdd) continue; 1624 1625 // Even worse, this child could conflict with another node already 1626 // selected for the DAG. If that is the case, ignore this child. 1627 for (DenseSet<ValuePair>::iterator T = PrunedDAG.begin(), 1628 E2 = PrunedDAG.end(); T != E2; ++T) { 1629 if (T->first == C->first.first || 1630 T->first == C->first.second || 1631 T->second == C->first.first || 1632 T->second == C->first.second || 1633 pairsConflict(*T, C->first, PairableInstUsers, 1634 UseCycleCheck ? &PairableInstUserMap : 0, 1635 UseCycleCheck ? &PairableInstUserPairSet : 0)) { 1636 CanAdd = false; 1637 break; 1638 } 1639 1640 CurrentPairs.insert(*T); 1641 } 1642 if (!CanAdd) continue; 1643 1644 // And check the queue too... 1645 for (SmallVector<ValuePairWithDepth, 32>::iterator C2 = Q.begin(), 1646 E2 = Q.end(); C2 != E2; ++C2) { 1647 if (C2->first.first == C->first.first || 1648 C2->first.first == C->first.second || 1649 C2->first.second == C->first.first || 1650 C2->first.second == C->first.second || 1651 pairsConflict(C2->first, C->first, PairableInstUsers, 1652 UseCycleCheck ? &PairableInstUserMap : 0, 1653 UseCycleCheck ? &PairableInstUserPairSet : 0)) { 1654 CanAdd = false; 1655 break; 1656 } 1657 1658 CurrentPairs.insert(C2->first); 1659 } 1660 if (!CanAdd) continue; 1661 1662 // Last but not least, check for a conflict with any of the 1663 // already-chosen pairs. 1664 for (DenseMap<Value *, Value *>::iterator C2 = 1665 ChosenPairs.begin(), E2 = ChosenPairs.end(); 1666 C2 != E2; ++C2) { 1667 if (pairsConflict(*C2, C->first, PairableInstUsers, 1668 UseCycleCheck ? &PairableInstUserMap : 0, 1669 UseCycleCheck ? &PairableInstUserPairSet : 0)) { 1670 CanAdd = false; 1671 break; 1672 } 1673 1674 CurrentPairs.insert(*C2); 1675 } 1676 if (!CanAdd) continue; 1677 1678 // To check for non-trivial cycles formed by the addition of the 1679 // current pair we've formed a list of all relevant pairs, now use a 1680 // graph walk to check for a cycle. We start from the current pair and 1681 // walk the use dag to see if we again reach the current pair. If we 1682 // do, then the current pair is rejected. 1683 1684 // FIXME: It may be more efficient to use a topological-ordering 1685 // algorithm to improve the cycle check. This should be investigated. 1686 if (UseCycleCheck && 1687 pairWillFormCycle(C->first, PairableInstUserMap, CurrentPairs)) 1688 continue; 1689 1690 // This child can be added, but we may have chosen it in preference 1691 // to an already-selected child. Check for this here, and if a 1692 // conflict is found, then remove the previously-selected child 1693 // before adding this one in its place. 1694 for (SmallVector<ValuePairWithDepth, 8>::iterator C2 1695 = BestChildren.begin(); C2 != BestChildren.end();) { 1696 if (C2->first.first == C->first.first || 1697 C2->first.first == C->first.second || 1698 C2->first.second == C->first.first || 1699 C2->first.second == C->first.second || 1700 pairsConflict(C2->first, C->first, PairableInstUsers)) 1701 C2 = BestChildren.erase(C2); 1702 else 1703 ++C2; 1704 } 1705 1706 BestChildren.push_back(ValuePairWithDepth(C->first, C->second)); 1707 } 1708 1709 for (SmallVector<ValuePairWithDepth, 8>::iterator C 1710 = BestChildren.begin(), E2 = BestChildren.end(); 1711 C != E2; ++C) { 1712 size_t DepthF = getDepthFactor(C->first.first); 1713 Q.push_back(ValuePairWithDepth(C->first, QTop.second+DepthF)); 1714 } 1715 } while (!Q.empty()); 1716 } 1717 1718 // This function finds the best dag of mututally-compatible connected 1719 // pairs, given the choice of root pairs as an iterator range. 1720 void BBVectorize::findBestDAGFor( 1721 DenseMap<Value *, std::vector<Value *> > &CandidatePairs, 1722 DenseSet<ValuePair> &CandidatePairsSet, 1723 DenseMap<ValuePair, int> &CandidatePairCostSavings, 1724 std::vector<Value *> &PairableInsts, 1725 DenseSet<ValuePair> &FixedOrderPairs, 1726 DenseMap<VPPair, unsigned> &PairConnectionTypes, 1727 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs, 1728 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairDeps, 1729 DenseSet<ValuePair> &PairableInstUsers, 1730 DenseMap<ValuePair, std::vector<ValuePair> > &PairableInstUserMap, 1731 DenseSet<VPPair> &PairableInstUserPairSet, 1732 DenseMap<Value *, Value *> &ChosenPairs, 1733 DenseSet<ValuePair> &BestDAG, size_t &BestMaxDepth, 1734 int &BestEffSize, Value *II, std::vector<Value *>&JJ, 1735 bool UseCycleCheck) { 1736 for (std::vector<Value *>::iterator J = JJ.begin(), JE = JJ.end(); 1737 J != JE; ++J) { 1738 ValuePair IJ(II, *J); 1739 if (!CandidatePairsSet.count(IJ)) 1740 continue; 1741 1742 // Before going any further, make sure that this pair does not 1743 // conflict with any already-selected pairs (see comment below 1744 // near the DAG pruning for more details). 1745 DenseSet<ValuePair> ChosenPairSet; 1746 bool DoesConflict = false; 1747 for (DenseMap<Value *, Value *>::iterator C = ChosenPairs.begin(), 1748 E = ChosenPairs.end(); C != E; ++C) { 1749 if (pairsConflict(*C, IJ, PairableInstUsers, 1750 UseCycleCheck ? &PairableInstUserMap : 0, 1751 UseCycleCheck ? &PairableInstUserPairSet : 0)) { 1752 DoesConflict = true; 1753 break; 1754 } 1755 1756 ChosenPairSet.insert(*C); 1757 } 1758 if (DoesConflict) continue; 1759 1760 if (UseCycleCheck && 1761 pairWillFormCycle(IJ, PairableInstUserMap, ChosenPairSet)) 1762 continue; 1763 1764 DenseMap<ValuePair, size_t> DAG; 1765 buildInitialDAGFor(CandidatePairs, CandidatePairsSet, 1766 PairableInsts, ConnectedPairs, 1767 PairableInstUsers, ChosenPairs, DAG, IJ); 1768 1769 // Because we'll keep the child with the largest depth, the largest 1770 // depth is still the same in the unpruned DAG. 1771 size_t MaxDepth = DAG.lookup(IJ); 1772 1773 DEBUG(if (DebugPairSelection) dbgs() << "BBV: found DAG for pair {" 1774 << *IJ.first << " <-> " << *IJ.second << "} of depth " << 1775 MaxDepth << " and size " << DAG.size() << "\n"); 1776 1777 // At this point the DAG has been constructed, but, may contain 1778 // contradictory children (meaning that different children of 1779 // some dag node may be attempting to fuse the same instruction). 1780 // So now we walk the dag again, in the case of a conflict, 1781 // keep only the child with the largest depth. To break a tie, 1782 // favor the first child. 1783 1784 DenseSet<ValuePair> PrunedDAG; 1785 pruneDAGFor(CandidatePairs, PairableInsts, ConnectedPairs, 1786 PairableInstUsers, PairableInstUserMap, 1787 PairableInstUserPairSet, 1788 ChosenPairs, DAG, PrunedDAG, IJ, UseCycleCheck); 1789 1790 int EffSize = 0; 1791 if (TTI) { 1792 DenseSet<Value *> PrunedDAGInstrs; 1793 for (DenseSet<ValuePair>::iterator S = PrunedDAG.begin(), 1794 E = PrunedDAG.end(); S != E; ++S) { 1795 PrunedDAGInstrs.insert(S->first); 1796 PrunedDAGInstrs.insert(S->second); 1797 } 1798 1799 // The set of pairs that have already contributed to the total cost. 1800 DenseSet<ValuePair> IncomingPairs; 1801 1802 // If the cost model were perfect, this might not be necessary; but we 1803 // need to make sure that we don't get stuck vectorizing our own 1804 // shuffle chains. 1805 bool HasNontrivialInsts = false; 1806 1807 // The node weights represent the cost savings associated with 1808 // fusing the pair of instructions. 1809 for (DenseSet<ValuePair>::iterator S = PrunedDAG.begin(), 1810 E = PrunedDAG.end(); S != E; ++S) { 1811 if (!isa<ShuffleVectorInst>(S->first) && 1812 !isa<InsertElementInst>(S->first) && 1813 !isa<ExtractElementInst>(S->first)) 1814 HasNontrivialInsts = true; 1815 1816 bool FlipOrder = false; 1817 1818 if (getDepthFactor(S->first)) { 1819 int ESContrib = CandidatePairCostSavings.find(*S)->second; 1820 DEBUG(if (DebugPairSelection) dbgs() << "\tweight {" 1821 << *S->first << " <-> " << *S->second << "} = " << 1822 ESContrib << "\n"); 1823 EffSize += ESContrib; 1824 } 1825 1826 // The edge weights contribute in a negative sense: they represent 1827 // the cost of shuffles. 1828 DenseMap<ValuePair, std::vector<ValuePair> >::iterator SS = 1829 ConnectedPairDeps.find(*S); 1830 if (SS != ConnectedPairDeps.end()) { 1831 unsigned NumDepsDirect = 0, NumDepsSwap = 0; 1832 for (std::vector<ValuePair>::iterator T = SS->second.begin(), 1833 TE = SS->second.end(); T != TE; ++T) { 1834 VPPair Q(*S, *T); 1835 if (!PrunedDAG.count(Q.second)) 1836 continue; 1837 DenseMap<VPPair, unsigned>::iterator R = 1838 PairConnectionTypes.find(VPPair(Q.second, Q.first)); 1839 assert(R != PairConnectionTypes.end() && 1840 "Cannot find pair connection type"); 1841 if (R->second == PairConnectionDirect) 1842 ++NumDepsDirect; 1843 else if (R->second == PairConnectionSwap) 1844 ++NumDepsSwap; 1845 } 1846 1847 // If there are more swaps than direct connections, then 1848 // the pair order will be flipped during fusion. So the real 1849 // number of swaps is the minimum number. 1850 FlipOrder = !FixedOrderPairs.count(*S) && 1851 ((NumDepsSwap > NumDepsDirect) || 1852 FixedOrderPairs.count(ValuePair(S->second, S->first))); 1853 1854 for (std::vector<ValuePair>::iterator T = SS->second.begin(), 1855 TE = SS->second.end(); T != TE; ++T) { 1856 VPPair Q(*S, *T); 1857 if (!PrunedDAG.count(Q.second)) 1858 continue; 1859 DenseMap<VPPair, unsigned>::iterator R = 1860 PairConnectionTypes.find(VPPair(Q.second, Q.first)); 1861 assert(R != PairConnectionTypes.end() && 1862 "Cannot find pair connection type"); 1863 Type *Ty1 = Q.second.first->getType(), 1864 *Ty2 = Q.second.second->getType(); 1865 Type *VTy = getVecTypeForPair(Ty1, Ty2); 1866 if ((R->second == PairConnectionDirect && FlipOrder) || 1867 (R->second == PairConnectionSwap && !FlipOrder) || 1868 R->second == PairConnectionSplat) { 1869 int ESContrib = (int) getInstrCost(Instruction::ShuffleVector, 1870 VTy, VTy); 1871 1872 if (VTy->getVectorNumElements() == 2) { 1873 if (R->second == PairConnectionSplat) 1874 ESContrib = std::min(ESContrib, (int) TTI->getShuffleCost( 1875 TargetTransformInfo::SK_Broadcast, VTy)); 1876 else 1877 ESContrib = std::min(ESContrib, (int) TTI->getShuffleCost( 1878 TargetTransformInfo::SK_Reverse, VTy)); 1879 } 1880 1881 DEBUG(if (DebugPairSelection) dbgs() << "\tcost {" << 1882 *Q.second.first << " <-> " << *Q.second.second << 1883 "} -> {" << 1884 *S->first << " <-> " << *S->second << "} = " << 1885 ESContrib << "\n"); 1886 EffSize -= ESContrib; 1887 } 1888 } 1889 } 1890 1891 // Compute the cost of outgoing edges. We assume that edges outgoing 1892 // to shuffles, inserts or extracts can be merged, and so contribute 1893 // no additional cost. 1894 if (!S->first->getType()->isVoidTy()) { 1895 Type *Ty1 = S->first->getType(), 1896 *Ty2 = S->second->getType(); 1897 Type *VTy = getVecTypeForPair(Ty1, Ty2); 1898 1899 bool NeedsExtraction = false; 1900 for (Value::use_iterator I = S->first->use_begin(), 1901 IE = S->first->use_end(); I != IE; ++I) { 1902 if (ShuffleVectorInst *SI = dyn_cast<ShuffleVectorInst>(*I)) { 1903 // Shuffle can be folded if it has no other input 1904 if (isa<UndefValue>(SI->getOperand(1))) 1905 continue; 1906 } 1907 if (isa<ExtractElementInst>(*I)) 1908 continue; 1909 if (PrunedDAGInstrs.count(*I)) 1910 continue; 1911 NeedsExtraction = true; 1912 break; 1913 } 1914 1915 if (NeedsExtraction) { 1916 int ESContrib; 1917 if (Ty1->isVectorTy()) { 1918 ESContrib = (int) getInstrCost(Instruction::ShuffleVector, 1919 Ty1, VTy); 1920 ESContrib = std::min(ESContrib, (int) TTI->getShuffleCost( 1921 TargetTransformInfo::SK_ExtractSubvector, VTy, 0, Ty1)); 1922 } else 1923 ESContrib = (int) TTI->getVectorInstrCost( 1924 Instruction::ExtractElement, VTy, 0); 1925 1926 DEBUG(if (DebugPairSelection) dbgs() << "\tcost {" << 1927 *S->first << "} = " << ESContrib << "\n"); 1928 EffSize -= ESContrib; 1929 } 1930 1931 NeedsExtraction = false; 1932 for (Value::use_iterator I = S->second->use_begin(), 1933 IE = S->second->use_end(); I != IE; ++I) { 1934 if (ShuffleVectorInst *SI = dyn_cast<ShuffleVectorInst>(*I)) { 1935 // Shuffle can be folded if it has no other input 1936 if (isa<UndefValue>(SI->getOperand(1))) 1937 continue; 1938 } 1939 if (isa<ExtractElementInst>(*I)) 1940 continue; 1941 if (PrunedDAGInstrs.count(*I)) 1942 continue; 1943 NeedsExtraction = true; 1944 break; 1945 } 1946 1947 if (NeedsExtraction) { 1948 int ESContrib; 1949 if (Ty2->isVectorTy()) { 1950 ESContrib = (int) getInstrCost(Instruction::ShuffleVector, 1951 Ty2, VTy); 1952 ESContrib = std::min(ESContrib, (int) TTI->getShuffleCost( 1953 TargetTransformInfo::SK_ExtractSubvector, VTy, 1954 Ty1->isVectorTy() ? Ty1->getVectorNumElements() : 1, Ty2)); 1955 } else 1956 ESContrib = (int) TTI->getVectorInstrCost( 1957 Instruction::ExtractElement, VTy, 1); 1958 DEBUG(if (DebugPairSelection) dbgs() << "\tcost {" << 1959 *S->second << "} = " << ESContrib << "\n"); 1960 EffSize -= ESContrib; 1961 } 1962 } 1963 1964 // Compute the cost of incoming edges. 1965 if (!isa<LoadInst>(S->first) && !isa<StoreInst>(S->first)) { 1966 Instruction *S1 = cast<Instruction>(S->first), 1967 *S2 = cast<Instruction>(S->second); 1968 for (unsigned o = 0; o < S1->getNumOperands(); ++o) { 1969 Value *O1 = S1->getOperand(o), *O2 = S2->getOperand(o); 1970 1971 // Combining constants into vector constants (or small vector 1972 // constants into larger ones are assumed free). 1973 if (isa<Constant>(O1) && isa<Constant>(O2)) 1974 continue; 1975 1976 if (FlipOrder) 1977 std::swap(O1, O2); 1978 1979 ValuePair VP = ValuePair(O1, O2); 1980 ValuePair VPR = ValuePair(O2, O1); 1981 1982 // Internal edges are not handled here. 1983 if (PrunedDAG.count(VP) || PrunedDAG.count(VPR)) 1984 continue; 1985 1986 Type *Ty1 = O1->getType(), 1987 *Ty2 = O2->getType(); 1988 Type *VTy = getVecTypeForPair(Ty1, Ty2); 1989 1990 // Combining vector operations of the same type is also assumed 1991 // folded with other operations. 1992 if (Ty1 == Ty2) { 1993 // If both are insert elements, then both can be widened. 1994 InsertElementInst *IEO1 = dyn_cast<InsertElementInst>(O1), 1995 *IEO2 = dyn_cast<InsertElementInst>(O2); 1996 if (IEO1 && IEO2 && isPureIEChain(IEO1) && isPureIEChain(IEO2)) 1997 continue; 1998 // If both are extract elements, and both have the same input 1999 // type, then they can be replaced with a shuffle 2000 ExtractElementInst *EIO1 = dyn_cast<ExtractElementInst>(O1), 2001 *EIO2 = dyn_cast<ExtractElementInst>(O2); 2002 if (EIO1 && EIO2 && 2003 EIO1->getOperand(0)->getType() == 2004 EIO2->getOperand(0)->getType()) 2005 continue; 2006 // If both are a shuffle with equal operand types and only two 2007 // unqiue operands, then they can be replaced with a single 2008 // shuffle 2009 ShuffleVectorInst *SIO1 = dyn_cast<ShuffleVectorInst>(O1), 2010 *SIO2 = dyn_cast<ShuffleVectorInst>(O2); 2011 if (SIO1 && SIO2 && 2012 SIO1->getOperand(0)->getType() == 2013 SIO2->getOperand(0)->getType()) { 2014 SmallSet<Value *, 4> SIOps; 2015 SIOps.insert(SIO1->getOperand(0)); 2016 SIOps.insert(SIO1->getOperand(1)); 2017 SIOps.insert(SIO2->getOperand(0)); 2018 SIOps.insert(SIO2->getOperand(1)); 2019 if (SIOps.size() <= 2) 2020 continue; 2021 } 2022 } 2023 2024 int ESContrib; 2025 // This pair has already been formed. 2026 if (IncomingPairs.count(VP)) { 2027 continue; 2028 } else if (IncomingPairs.count(VPR)) { 2029 ESContrib = (int) getInstrCost(Instruction::ShuffleVector, 2030 VTy, VTy); 2031 2032 if (VTy->getVectorNumElements() == 2) 2033 ESContrib = std::min(ESContrib, (int) TTI->getShuffleCost( 2034 TargetTransformInfo::SK_Reverse, VTy)); 2035 } else if (!Ty1->isVectorTy() && !Ty2->isVectorTy()) { 2036 ESContrib = (int) TTI->getVectorInstrCost( 2037 Instruction::InsertElement, VTy, 0); 2038 ESContrib += (int) TTI->getVectorInstrCost( 2039 Instruction::InsertElement, VTy, 1); 2040 } else if (!Ty1->isVectorTy()) { 2041 // O1 needs to be inserted into a vector of size O2, and then 2042 // both need to be shuffled together. 2043 ESContrib = (int) TTI->getVectorInstrCost( 2044 Instruction::InsertElement, Ty2, 0); 2045 ESContrib += (int) getInstrCost(Instruction::ShuffleVector, 2046 VTy, Ty2); 2047 } else if (!Ty2->isVectorTy()) { 2048 // O2 needs to be inserted into a vector of size O1, and then 2049 // both need to be shuffled together. 2050 ESContrib = (int) TTI->getVectorInstrCost( 2051 Instruction::InsertElement, Ty1, 0); 2052 ESContrib += (int) getInstrCost(Instruction::ShuffleVector, 2053 VTy, Ty1); 2054 } else { 2055 Type *TyBig = Ty1, *TySmall = Ty2; 2056 if (Ty2->getVectorNumElements() > Ty1->getVectorNumElements()) 2057 std::swap(TyBig, TySmall); 2058 2059 ESContrib = (int) getInstrCost(Instruction::ShuffleVector, 2060 VTy, TyBig); 2061 if (TyBig != TySmall) 2062 ESContrib += (int) getInstrCost(Instruction::ShuffleVector, 2063 TyBig, TySmall); 2064 } 2065 2066 DEBUG(if (DebugPairSelection) dbgs() << "\tcost {" 2067 << *O1 << " <-> " << *O2 << "} = " << 2068 ESContrib << "\n"); 2069 EffSize -= ESContrib; 2070 IncomingPairs.insert(VP); 2071 } 2072 } 2073 } 2074 2075 if (!HasNontrivialInsts) { 2076 DEBUG(if (DebugPairSelection) dbgs() << 2077 "\tNo non-trivial instructions in DAG;" 2078 " override to zero effective size\n"); 2079 EffSize = 0; 2080 } 2081 } else { 2082 for (DenseSet<ValuePair>::iterator S = PrunedDAG.begin(), 2083 E = PrunedDAG.end(); S != E; ++S) 2084 EffSize += (int) getDepthFactor(S->first); 2085 } 2086 2087 DEBUG(if (DebugPairSelection) 2088 dbgs() << "BBV: found pruned DAG for pair {" 2089 << *IJ.first << " <-> " << *IJ.second << "} of depth " << 2090 MaxDepth << " and size " << PrunedDAG.size() << 2091 " (effective size: " << EffSize << ")\n"); 2092 if (((TTI && !UseChainDepthWithTI) || 2093 MaxDepth >= Config.ReqChainDepth) && 2094 EffSize > 0 && EffSize > BestEffSize) { 2095 BestMaxDepth = MaxDepth; 2096 BestEffSize = EffSize; 2097 BestDAG = PrunedDAG; 2098 } 2099 } 2100 } 2101 2102 // Given the list of candidate pairs, this function selects those 2103 // that will be fused into vector instructions. 2104 void BBVectorize::choosePairs( 2105 DenseMap<Value *, std::vector<Value *> > &CandidatePairs, 2106 DenseSet<ValuePair> &CandidatePairsSet, 2107 DenseMap<ValuePair, int> &CandidatePairCostSavings, 2108 std::vector<Value *> &PairableInsts, 2109 DenseSet<ValuePair> &FixedOrderPairs, 2110 DenseMap<VPPair, unsigned> &PairConnectionTypes, 2111 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs, 2112 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairDeps, 2113 DenseSet<ValuePair> &PairableInstUsers, 2114 DenseMap<Value *, Value *>& ChosenPairs) { 2115 bool UseCycleCheck = 2116 CandidatePairsSet.size() <= Config.MaxCandPairsForCycleCheck; 2117 2118 DenseMap<Value *, std::vector<Value *> > CandidatePairs2; 2119 for (DenseSet<ValuePair>::iterator I = CandidatePairsSet.begin(), 2120 E = CandidatePairsSet.end(); I != E; ++I) { 2121 std::vector<Value *> &JJ = CandidatePairs2[I->second]; 2122 if (JJ.empty()) JJ.reserve(32); 2123 JJ.push_back(I->first); 2124 } 2125 2126 DenseMap<ValuePair, std::vector<ValuePair> > PairableInstUserMap; 2127 DenseSet<VPPair> PairableInstUserPairSet; 2128 for (std::vector<Value *>::iterator I = PairableInsts.begin(), 2129 E = PairableInsts.end(); I != E; ++I) { 2130 // The number of possible pairings for this variable: 2131 size_t NumChoices = CandidatePairs.lookup(*I).size(); 2132 if (!NumChoices) continue; 2133 2134 std::vector<Value *> &JJ = CandidatePairs[*I]; 2135 2136 // The best pair to choose and its dag: 2137 size_t BestMaxDepth = 0; 2138 int BestEffSize = 0; 2139 DenseSet<ValuePair> BestDAG; 2140 findBestDAGFor(CandidatePairs, CandidatePairsSet, 2141 CandidatePairCostSavings, 2142 PairableInsts, FixedOrderPairs, PairConnectionTypes, 2143 ConnectedPairs, ConnectedPairDeps, 2144 PairableInstUsers, PairableInstUserMap, 2145 PairableInstUserPairSet, ChosenPairs, 2146 BestDAG, BestMaxDepth, BestEffSize, *I, JJ, 2147 UseCycleCheck); 2148 2149 if (BestDAG.empty()) 2150 continue; 2151 2152 // A dag has been chosen (or not) at this point. If no dag was 2153 // chosen, then this instruction, I, cannot be paired (and is no longer 2154 // considered). 2155 2156 DEBUG(dbgs() << "BBV: selected pairs in the best DAG for: " 2157 << *cast<Instruction>(*I) << "\n"); 2158 2159 for (DenseSet<ValuePair>::iterator S = BestDAG.begin(), 2160 SE2 = BestDAG.end(); S != SE2; ++S) { 2161 // Insert the members of this dag into the list of chosen pairs. 2162 ChosenPairs.insert(ValuePair(S->first, S->second)); 2163 DEBUG(dbgs() << "BBV: selected pair: " << *S->first << " <-> " << 2164 *S->second << "\n"); 2165 2166 // Remove all candidate pairs that have values in the chosen dag. 2167 std::vector<Value *> &KK = CandidatePairs[S->first]; 2168 for (std::vector<Value *>::iterator K = KK.begin(), KE = KK.end(); 2169 K != KE; ++K) { 2170 if (*K == S->second) 2171 continue; 2172 2173 CandidatePairsSet.erase(ValuePair(S->first, *K)); 2174 } 2175 2176 std::vector<Value *> &LL = CandidatePairs2[S->second]; 2177 for (std::vector<Value *>::iterator L = LL.begin(), LE = LL.end(); 2178 L != LE; ++L) { 2179 if (*L == S->first) 2180 continue; 2181 2182 CandidatePairsSet.erase(ValuePair(*L, S->second)); 2183 } 2184 2185 std::vector<Value *> &MM = CandidatePairs[S->second]; 2186 for (std::vector<Value *>::iterator M = MM.begin(), ME = MM.end(); 2187 M != ME; ++M) { 2188 assert(*M != S->first && "Flipped pair in candidate list?"); 2189 CandidatePairsSet.erase(ValuePair(S->second, *M)); 2190 } 2191 2192 std::vector<Value *> &NN = CandidatePairs2[S->first]; 2193 for (std::vector<Value *>::iterator N = NN.begin(), NE = NN.end(); 2194 N != NE; ++N) { 2195 assert(*N != S->second && "Flipped pair in candidate list?"); 2196 CandidatePairsSet.erase(ValuePair(*N, S->first)); 2197 } 2198 } 2199 } 2200 2201 DEBUG(dbgs() << "BBV: selected " << ChosenPairs.size() << " pairs.\n"); 2202 } 2203 2204 std::string getReplacementName(Instruction *I, bool IsInput, unsigned o, 2205 unsigned n = 0) { 2206 if (!I->hasName()) 2207 return ""; 2208 2209 return (I->getName() + (IsInput ? ".v.i" : ".v.r") + utostr(o) + 2210 (n > 0 ? "." + utostr(n) : "")).str(); 2211 } 2212 2213 // Returns the value that is to be used as the pointer input to the vector 2214 // instruction that fuses I with J. 2215 Value *BBVectorize::getReplacementPointerInput(LLVMContext& Context, 2216 Instruction *I, Instruction *J, unsigned o) { 2217 Value *IPtr, *JPtr; 2218 unsigned IAlignment, JAlignment, IAddressSpace, JAddressSpace; 2219 int64_t OffsetInElmts; 2220 2221 // Note: the analysis might fail here, that is why the pair order has 2222 // been precomputed (OffsetInElmts must be unused here). 2223 (void) getPairPtrInfo(I, J, IPtr, JPtr, IAlignment, JAlignment, 2224 IAddressSpace, JAddressSpace, 2225 OffsetInElmts, false); 2226 2227 // The pointer value is taken to be the one with the lowest offset. 2228 Value *VPtr = IPtr; 2229 2230 Type *ArgTypeI = cast<PointerType>(IPtr->getType())->getElementType(); 2231 Type *ArgTypeJ = cast<PointerType>(JPtr->getType())->getElementType(); 2232 Type *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ); 2233 Type *VArgPtrType = PointerType::get(VArgType, 2234 cast<PointerType>(IPtr->getType())->getAddressSpace()); 2235 return new BitCastInst(VPtr, VArgPtrType, getReplacementName(I, true, o), 2236 /* insert before */ I); 2237 } 2238 2239 void BBVectorize::fillNewShuffleMask(LLVMContext& Context, Instruction *J, 2240 unsigned MaskOffset, unsigned NumInElem, 2241 unsigned NumInElem1, unsigned IdxOffset, 2242 std::vector<Constant*> &Mask) { 2243 unsigned NumElem1 = cast<VectorType>(J->getType())->getNumElements(); 2244 for (unsigned v = 0; v < NumElem1; ++v) { 2245 int m = cast<ShuffleVectorInst>(J)->getMaskValue(v); 2246 if (m < 0) { 2247 Mask[v+MaskOffset] = UndefValue::get(Type::getInt32Ty(Context)); 2248 } else { 2249 unsigned mm = m + (int) IdxOffset; 2250 if (m >= (int) NumInElem1) 2251 mm += (int) NumInElem; 2252 2253 Mask[v+MaskOffset] = 2254 ConstantInt::get(Type::getInt32Ty(Context), mm); 2255 } 2256 } 2257 } 2258 2259 // Returns the value that is to be used as the vector-shuffle mask to the 2260 // vector instruction that fuses I with J. 2261 Value *BBVectorize::getReplacementShuffleMask(LLVMContext& Context, 2262 Instruction *I, Instruction *J) { 2263 // This is the shuffle mask. We need to append the second 2264 // mask to the first, and the numbers need to be adjusted. 2265 2266 Type *ArgTypeI = I->getType(); 2267 Type *ArgTypeJ = J->getType(); 2268 Type *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ); 2269 2270 unsigned NumElemI = cast<VectorType>(ArgTypeI)->getNumElements(); 2271 2272 // Get the total number of elements in the fused vector type. 2273 // By definition, this must equal the number of elements in 2274 // the final mask. 2275 unsigned NumElem = cast<VectorType>(VArgType)->getNumElements(); 2276 std::vector<Constant*> Mask(NumElem); 2277 2278 Type *OpTypeI = I->getOperand(0)->getType(); 2279 unsigned NumInElemI = cast<VectorType>(OpTypeI)->getNumElements(); 2280 Type *OpTypeJ = J->getOperand(0)->getType(); 2281 unsigned NumInElemJ = cast<VectorType>(OpTypeJ)->getNumElements(); 2282 2283 // The fused vector will be: 2284 // ----------------------------------------------------- 2285 // | NumInElemI | NumInElemJ | NumInElemI | NumInElemJ | 2286 // ----------------------------------------------------- 2287 // from which we'll extract NumElem total elements (where the first NumElemI 2288 // of them come from the mask in I and the remainder come from the mask 2289 // in J. 2290 2291 // For the mask from the first pair... 2292 fillNewShuffleMask(Context, I, 0, NumInElemJ, NumInElemI, 2293 0, Mask); 2294 2295 // For the mask from the second pair... 2296 fillNewShuffleMask(Context, J, NumElemI, NumInElemI, NumInElemJ, 2297 NumInElemI, Mask); 2298 2299 return ConstantVector::get(Mask); 2300 } 2301 2302 bool BBVectorize::expandIEChain(LLVMContext& Context, Instruction *I, 2303 Instruction *J, unsigned o, Value *&LOp, 2304 unsigned numElemL, 2305 Type *ArgTypeL, Type *ArgTypeH, 2306 bool IBeforeJ, unsigned IdxOff) { 2307 bool ExpandedIEChain = false; 2308 if (InsertElementInst *LIE = dyn_cast<InsertElementInst>(LOp)) { 2309 // If we have a pure insertelement chain, then this can be rewritten 2310 // into a chain that directly builds the larger type. 2311 if (isPureIEChain(LIE)) { 2312 SmallVector<Value *, 8> VectElemts(numElemL, 2313 UndefValue::get(ArgTypeL->getScalarType())); 2314 InsertElementInst *LIENext = LIE; 2315 do { 2316 unsigned Idx = 2317 cast<ConstantInt>(LIENext->getOperand(2))->getSExtValue(); 2318 VectElemts[Idx] = LIENext->getOperand(1); 2319 } while ((LIENext = 2320 dyn_cast<InsertElementInst>(LIENext->getOperand(0)))); 2321 2322 LIENext = 0; 2323 Value *LIEPrev = UndefValue::get(ArgTypeH); 2324 for (unsigned i = 0; i < numElemL; ++i) { 2325 if (isa<UndefValue>(VectElemts[i])) continue; 2326 LIENext = InsertElementInst::Create(LIEPrev, VectElemts[i], 2327 ConstantInt::get(Type::getInt32Ty(Context), 2328 i + IdxOff), 2329 getReplacementName(IBeforeJ ? I : J, 2330 true, o, i+1)); 2331 LIENext->insertBefore(IBeforeJ ? J : I); 2332 LIEPrev = LIENext; 2333 } 2334 2335 LOp = LIENext ? (Value*) LIENext : UndefValue::get(ArgTypeH); 2336 ExpandedIEChain = true; 2337 } 2338 } 2339 2340 return ExpandedIEChain; 2341 } 2342 2343 // Returns the value to be used as the specified operand of the vector 2344 // instruction that fuses I with J. 2345 Value *BBVectorize::getReplacementInput(LLVMContext& Context, Instruction *I, 2346 Instruction *J, unsigned o, bool IBeforeJ) { 2347 Value *CV0 = ConstantInt::get(Type::getInt32Ty(Context), 0); 2348 Value *CV1 = ConstantInt::get(Type::getInt32Ty(Context), 1); 2349 2350 // Compute the fused vector type for this operand 2351 Type *ArgTypeI = I->getOperand(o)->getType(); 2352 Type *ArgTypeJ = J->getOperand(o)->getType(); 2353 VectorType *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ); 2354 2355 Instruction *L = I, *H = J; 2356 Type *ArgTypeL = ArgTypeI, *ArgTypeH = ArgTypeJ; 2357 2358 unsigned numElemL; 2359 if (ArgTypeL->isVectorTy()) 2360 numElemL = cast<VectorType>(ArgTypeL)->getNumElements(); 2361 else 2362 numElemL = 1; 2363 2364 unsigned numElemH; 2365 if (ArgTypeH->isVectorTy()) 2366 numElemH = cast<VectorType>(ArgTypeH)->getNumElements(); 2367 else 2368 numElemH = 1; 2369 2370 Value *LOp = L->getOperand(o); 2371 Value *HOp = H->getOperand(o); 2372 unsigned numElem = VArgType->getNumElements(); 2373 2374 // First, we check if we can reuse the "original" vector outputs (if these 2375 // exist). We might need a shuffle. 2376 ExtractElementInst *LEE = dyn_cast<ExtractElementInst>(LOp); 2377 ExtractElementInst *HEE = dyn_cast<ExtractElementInst>(HOp); 2378 ShuffleVectorInst *LSV = dyn_cast<ShuffleVectorInst>(LOp); 2379 ShuffleVectorInst *HSV = dyn_cast<ShuffleVectorInst>(HOp); 2380 2381 // FIXME: If we're fusing shuffle instructions, then we can't apply this 2382 // optimization. The input vectors to the shuffle might be a different 2383 // length from the shuffle outputs. Unfortunately, the replacement 2384 // shuffle mask has already been formed, and the mask entries are sensitive 2385 // to the sizes of the inputs. 2386 bool IsSizeChangeShuffle = 2387 isa<ShuffleVectorInst>(L) && 2388 (LOp->getType() != L->getType() || HOp->getType() != H->getType()); 2389 2390 if ((LEE || LSV) && (HEE || HSV) && !IsSizeChangeShuffle) { 2391 // We can have at most two unique vector inputs. 2392 bool CanUseInputs = true; 2393 Value *I1, *I2 = 0; 2394 if (LEE) { 2395 I1 = LEE->getOperand(0); 2396 } else { 2397 I1 = LSV->getOperand(0); 2398 I2 = LSV->getOperand(1); 2399 if (I2 == I1 || isa<UndefValue>(I2)) 2400 I2 = 0; 2401 } 2402 2403 if (HEE) { 2404 Value *I3 = HEE->getOperand(0); 2405 if (!I2 && I3 != I1) 2406 I2 = I3; 2407 else if (I3 != I1 && I3 != I2) 2408 CanUseInputs = false; 2409 } else { 2410 Value *I3 = HSV->getOperand(0); 2411 if (!I2 && I3 != I1) 2412 I2 = I3; 2413 else if (I3 != I1 && I3 != I2) 2414 CanUseInputs = false; 2415 2416 if (CanUseInputs) { 2417 Value *I4 = HSV->getOperand(1); 2418 if (!isa<UndefValue>(I4)) { 2419 if (!I2 && I4 != I1) 2420 I2 = I4; 2421 else if (I4 != I1 && I4 != I2) 2422 CanUseInputs = false; 2423 } 2424 } 2425 } 2426 2427 if (CanUseInputs) { 2428 unsigned LOpElem = 2429 cast<VectorType>(cast<Instruction>(LOp)->getOperand(0)->getType()) 2430 ->getNumElements(); 2431 unsigned HOpElem = 2432 cast<VectorType>(cast<Instruction>(HOp)->getOperand(0)->getType()) 2433 ->getNumElements(); 2434 2435 // We have one or two input vectors. We need to map each index of the 2436 // operands to the index of the original vector. 2437 SmallVector<std::pair<int, int>, 8> II(numElem); 2438 for (unsigned i = 0; i < numElemL; ++i) { 2439 int Idx, INum; 2440 if (LEE) { 2441 Idx = 2442 cast<ConstantInt>(LEE->getOperand(1))->getSExtValue(); 2443 INum = LEE->getOperand(0) == I1 ? 0 : 1; 2444 } else { 2445 Idx = LSV->getMaskValue(i); 2446 if (Idx < (int) LOpElem) { 2447 INum = LSV->getOperand(0) == I1 ? 0 : 1; 2448 } else { 2449 Idx -= LOpElem; 2450 INum = LSV->getOperand(1) == I1 ? 0 : 1; 2451 } 2452 } 2453 2454 II[i] = std::pair<int, int>(Idx, INum); 2455 } 2456 for (unsigned i = 0; i < numElemH; ++i) { 2457 int Idx, INum; 2458 if (HEE) { 2459 Idx = 2460 cast<ConstantInt>(HEE->getOperand(1))->getSExtValue(); 2461 INum = HEE->getOperand(0) == I1 ? 0 : 1; 2462 } else { 2463 Idx = HSV->getMaskValue(i); 2464 if (Idx < (int) HOpElem) { 2465 INum = HSV->getOperand(0) == I1 ? 0 : 1; 2466 } else { 2467 Idx -= HOpElem; 2468 INum = HSV->getOperand(1) == I1 ? 0 : 1; 2469 } 2470 } 2471 2472 II[i + numElemL] = std::pair<int, int>(Idx, INum); 2473 } 2474 2475 // We now have an array which tells us from which index of which 2476 // input vector each element of the operand comes. 2477 VectorType *I1T = cast<VectorType>(I1->getType()); 2478 unsigned I1Elem = I1T->getNumElements(); 2479 2480 if (!I2) { 2481 // In this case there is only one underlying vector input. Check for 2482 // the trivial case where we can use the input directly. 2483 if (I1Elem == numElem) { 2484 bool ElemInOrder = true; 2485 for (unsigned i = 0; i < numElem; ++i) { 2486 if (II[i].first != (int) i && II[i].first != -1) { 2487 ElemInOrder = false; 2488 break; 2489 } 2490 } 2491 2492 if (ElemInOrder) 2493 return I1; 2494 } 2495 2496 // A shuffle is needed. 2497 std::vector<Constant *> Mask(numElem); 2498 for (unsigned i = 0; i < numElem; ++i) { 2499 int Idx = II[i].first; 2500 if (Idx == -1) 2501 Mask[i] = UndefValue::get(Type::getInt32Ty(Context)); 2502 else 2503 Mask[i] = ConstantInt::get(Type::getInt32Ty(Context), Idx); 2504 } 2505 2506 Instruction *S = 2507 new ShuffleVectorInst(I1, UndefValue::get(I1T), 2508 ConstantVector::get(Mask), 2509 getReplacementName(IBeforeJ ? I : J, 2510 true, o)); 2511 S->insertBefore(IBeforeJ ? J : I); 2512 return S; 2513 } 2514 2515 VectorType *I2T = cast<VectorType>(I2->getType()); 2516 unsigned I2Elem = I2T->getNumElements(); 2517 2518 // This input comes from two distinct vectors. The first step is to 2519 // make sure that both vectors are the same length. If not, the 2520 // smaller one will need to grow before they can be shuffled together. 2521 if (I1Elem < I2Elem) { 2522 std::vector<Constant *> Mask(I2Elem); 2523 unsigned v = 0; 2524 for (; v < I1Elem; ++v) 2525 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v); 2526 for (; v < I2Elem; ++v) 2527 Mask[v] = UndefValue::get(Type::getInt32Ty(Context)); 2528 2529 Instruction *NewI1 = 2530 new ShuffleVectorInst(I1, UndefValue::get(I1T), 2531 ConstantVector::get(Mask), 2532 getReplacementName(IBeforeJ ? I : J, 2533 true, o, 1)); 2534 NewI1->insertBefore(IBeforeJ ? J : I); 2535 I1 = NewI1; 2536 I1T = I2T; 2537 I1Elem = I2Elem; 2538 } else if (I1Elem > I2Elem) { 2539 std::vector<Constant *> Mask(I1Elem); 2540 unsigned v = 0; 2541 for (; v < I2Elem; ++v) 2542 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v); 2543 for (; v < I1Elem; ++v) 2544 Mask[v] = UndefValue::get(Type::getInt32Ty(Context)); 2545 2546 Instruction *NewI2 = 2547 new ShuffleVectorInst(I2, UndefValue::get(I2T), 2548 ConstantVector::get(Mask), 2549 getReplacementName(IBeforeJ ? I : J, 2550 true, o, 1)); 2551 NewI2->insertBefore(IBeforeJ ? J : I); 2552 I2 = NewI2; 2553 I2T = I1T; 2554 I2Elem = I1Elem; 2555 } 2556 2557 // Now that both I1 and I2 are the same length we can shuffle them 2558 // together (and use the result). 2559 std::vector<Constant *> Mask(numElem); 2560 for (unsigned v = 0; v < numElem; ++v) { 2561 if (II[v].first == -1) { 2562 Mask[v] = UndefValue::get(Type::getInt32Ty(Context)); 2563 } else { 2564 int Idx = II[v].first + II[v].second * I1Elem; 2565 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), Idx); 2566 } 2567 } 2568 2569 Instruction *NewOp = 2570 new ShuffleVectorInst(I1, I2, ConstantVector::get(Mask), 2571 getReplacementName(IBeforeJ ? I : J, true, o)); 2572 NewOp->insertBefore(IBeforeJ ? J : I); 2573 return NewOp; 2574 } 2575 } 2576 2577 Type *ArgType = ArgTypeL; 2578 if (numElemL < numElemH) { 2579 if (numElemL == 1 && expandIEChain(Context, I, J, o, HOp, numElemH, 2580 ArgTypeL, VArgType, IBeforeJ, 1)) { 2581 // This is another short-circuit case: we're combining a scalar into 2582 // a vector that is formed by an IE chain. We've just expanded the IE 2583 // chain, now insert the scalar and we're done. 2584 2585 Instruction *S = InsertElementInst::Create(HOp, LOp, CV0, 2586 getReplacementName(IBeforeJ ? I : J, true, o)); 2587 S->insertBefore(IBeforeJ ? J : I); 2588 return S; 2589 } else if (!expandIEChain(Context, I, J, o, LOp, numElemL, ArgTypeL, 2590 ArgTypeH, IBeforeJ)) { 2591 // The two vector inputs to the shuffle must be the same length, 2592 // so extend the smaller vector to be the same length as the larger one. 2593 Instruction *NLOp; 2594 if (numElemL > 1) { 2595 2596 std::vector<Constant *> Mask(numElemH); 2597 unsigned v = 0; 2598 for (; v < numElemL; ++v) 2599 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v); 2600 for (; v < numElemH; ++v) 2601 Mask[v] = UndefValue::get(Type::getInt32Ty(Context)); 2602 2603 NLOp = new ShuffleVectorInst(LOp, UndefValue::get(ArgTypeL), 2604 ConstantVector::get(Mask), 2605 getReplacementName(IBeforeJ ? I : J, 2606 true, o, 1)); 2607 } else { 2608 NLOp = InsertElementInst::Create(UndefValue::get(ArgTypeH), LOp, CV0, 2609 getReplacementName(IBeforeJ ? I : J, 2610 true, o, 1)); 2611 } 2612 2613 NLOp->insertBefore(IBeforeJ ? J : I); 2614 LOp = NLOp; 2615 } 2616 2617 ArgType = ArgTypeH; 2618 } else if (numElemL > numElemH) { 2619 if (numElemH == 1 && expandIEChain(Context, I, J, o, LOp, numElemL, 2620 ArgTypeH, VArgType, IBeforeJ)) { 2621 Instruction *S = 2622 InsertElementInst::Create(LOp, HOp, 2623 ConstantInt::get(Type::getInt32Ty(Context), 2624 numElemL), 2625 getReplacementName(IBeforeJ ? I : J, 2626 true, o)); 2627 S->insertBefore(IBeforeJ ? J : I); 2628 return S; 2629 } else if (!expandIEChain(Context, I, J, o, HOp, numElemH, ArgTypeH, 2630 ArgTypeL, IBeforeJ)) { 2631 Instruction *NHOp; 2632 if (numElemH > 1) { 2633 std::vector<Constant *> Mask(numElemL); 2634 unsigned v = 0; 2635 for (; v < numElemH; ++v) 2636 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v); 2637 for (; v < numElemL; ++v) 2638 Mask[v] = UndefValue::get(Type::getInt32Ty(Context)); 2639 2640 NHOp = new ShuffleVectorInst(HOp, UndefValue::get(ArgTypeH), 2641 ConstantVector::get(Mask), 2642 getReplacementName(IBeforeJ ? I : J, 2643 true, o, 1)); 2644 } else { 2645 NHOp = InsertElementInst::Create(UndefValue::get(ArgTypeL), HOp, CV0, 2646 getReplacementName(IBeforeJ ? I : J, 2647 true, o, 1)); 2648 } 2649 2650 NHOp->insertBefore(IBeforeJ ? J : I); 2651 HOp = NHOp; 2652 } 2653 } 2654 2655 if (ArgType->isVectorTy()) { 2656 unsigned numElem = cast<VectorType>(VArgType)->getNumElements(); 2657 std::vector<Constant*> Mask(numElem); 2658 for (unsigned v = 0; v < numElem; ++v) { 2659 unsigned Idx = v; 2660 // If the low vector was expanded, we need to skip the extra 2661 // undefined entries. 2662 if (v >= numElemL && numElemH > numElemL) 2663 Idx += (numElemH - numElemL); 2664 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), Idx); 2665 } 2666 2667 Instruction *BV = new ShuffleVectorInst(LOp, HOp, 2668 ConstantVector::get(Mask), 2669 getReplacementName(IBeforeJ ? I : J, true, o)); 2670 BV->insertBefore(IBeforeJ ? J : I); 2671 return BV; 2672 } 2673 2674 Instruction *BV1 = InsertElementInst::Create( 2675 UndefValue::get(VArgType), LOp, CV0, 2676 getReplacementName(IBeforeJ ? I : J, 2677 true, o, 1)); 2678 BV1->insertBefore(IBeforeJ ? J : I); 2679 Instruction *BV2 = InsertElementInst::Create(BV1, HOp, CV1, 2680 getReplacementName(IBeforeJ ? I : J, 2681 true, o, 2)); 2682 BV2->insertBefore(IBeforeJ ? J : I); 2683 return BV2; 2684 } 2685 2686 // This function creates an array of values that will be used as the inputs 2687 // to the vector instruction that fuses I with J. 2688 void BBVectorize::getReplacementInputsForPair(LLVMContext& Context, 2689 Instruction *I, Instruction *J, 2690 SmallVector<Value *, 3> &ReplacedOperands, 2691 bool IBeforeJ) { 2692 unsigned NumOperands = I->getNumOperands(); 2693 2694 for (unsigned p = 0, o = NumOperands-1; p < NumOperands; ++p, --o) { 2695 // Iterate backward so that we look at the store pointer 2696 // first and know whether or not we need to flip the inputs. 2697 2698 if (isa<LoadInst>(I) || (o == 1 && isa<StoreInst>(I))) { 2699 // This is the pointer for a load/store instruction. 2700 ReplacedOperands[o] = getReplacementPointerInput(Context, I, J, o); 2701 continue; 2702 } else if (isa<CallInst>(I)) { 2703 Function *F = cast<CallInst>(I)->getCalledFunction(); 2704 Intrinsic::ID IID = (Intrinsic::ID) F->getIntrinsicID(); 2705 if (o == NumOperands-1) { 2706 BasicBlock &BB = *I->getParent(); 2707 2708 Module *M = BB.getParent()->getParent(); 2709 Type *ArgTypeI = I->getType(); 2710 Type *ArgTypeJ = J->getType(); 2711 Type *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ); 2712 2713 ReplacedOperands[o] = Intrinsic::getDeclaration(M, IID, VArgType); 2714 continue; 2715 } else if (IID == Intrinsic::powi && o == 1) { 2716 // The second argument of powi is a single integer and we've already 2717 // checked that both arguments are equal. As a result, we just keep 2718 // I's second argument. 2719 ReplacedOperands[o] = I->getOperand(o); 2720 continue; 2721 } 2722 } else if (isa<ShuffleVectorInst>(I) && o == NumOperands-1) { 2723 ReplacedOperands[o] = getReplacementShuffleMask(Context, I, J); 2724 continue; 2725 } 2726 2727 ReplacedOperands[o] = getReplacementInput(Context, I, J, o, IBeforeJ); 2728 } 2729 } 2730 2731 // This function creates two values that represent the outputs of the 2732 // original I and J instructions. These are generally vector shuffles 2733 // or extracts. In many cases, these will end up being unused and, thus, 2734 // eliminated by later passes. 2735 void BBVectorize::replaceOutputsOfPair(LLVMContext& Context, Instruction *I, 2736 Instruction *J, Instruction *K, 2737 Instruction *&InsertionPt, 2738 Instruction *&K1, Instruction *&K2) { 2739 if (isa<StoreInst>(I)) { 2740 AA->replaceWithNewValue(I, K); 2741 AA->replaceWithNewValue(J, K); 2742 } else { 2743 Type *IType = I->getType(); 2744 Type *JType = J->getType(); 2745 2746 VectorType *VType = getVecTypeForPair(IType, JType); 2747 unsigned numElem = VType->getNumElements(); 2748 2749 unsigned numElemI, numElemJ; 2750 if (IType->isVectorTy()) 2751 numElemI = cast<VectorType>(IType)->getNumElements(); 2752 else 2753 numElemI = 1; 2754 2755 if (JType->isVectorTy()) 2756 numElemJ = cast<VectorType>(JType)->getNumElements(); 2757 else 2758 numElemJ = 1; 2759 2760 if (IType->isVectorTy()) { 2761 std::vector<Constant*> Mask1(numElemI), Mask2(numElemI); 2762 for (unsigned v = 0; v < numElemI; ++v) { 2763 Mask1[v] = ConstantInt::get(Type::getInt32Ty(Context), v); 2764 Mask2[v] = ConstantInt::get(Type::getInt32Ty(Context), numElemJ+v); 2765 } 2766 2767 K1 = new ShuffleVectorInst(K, UndefValue::get(VType), 2768 ConstantVector::get( Mask1), 2769 getReplacementName(K, false, 1)); 2770 } else { 2771 Value *CV0 = ConstantInt::get(Type::getInt32Ty(Context), 0); 2772 K1 = ExtractElementInst::Create(K, CV0, 2773 getReplacementName(K, false, 1)); 2774 } 2775 2776 if (JType->isVectorTy()) { 2777 std::vector<Constant*> Mask1(numElemJ), Mask2(numElemJ); 2778 for (unsigned v = 0; v < numElemJ; ++v) { 2779 Mask1[v] = ConstantInt::get(Type::getInt32Ty(Context), v); 2780 Mask2[v] = ConstantInt::get(Type::getInt32Ty(Context), numElemI+v); 2781 } 2782 2783 K2 = new ShuffleVectorInst(K, UndefValue::get(VType), 2784 ConstantVector::get( Mask2), 2785 getReplacementName(K, false, 2)); 2786 } else { 2787 Value *CV1 = ConstantInt::get(Type::getInt32Ty(Context), numElem-1); 2788 K2 = ExtractElementInst::Create(K, CV1, 2789 getReplacementName(K, false, 2)); 2790 } 2791 2792 K1->insertAfter(K); 2793 K2->insertAfter(K1); 2794 InsertionPt = K2; 2795 } 2796 } 2797 2798 // Move all uses of the function I (including pairing-induced uses) after J. 2799 bool BBVectorize::canMoveUsesOfIAfterJ(BasicBlock &BB, 2800 DenseSet<ValuePair> &LoadMoveSetPairs, 2801 Instruction *I, Instruction *J) { 2802 // Skip to the first instruction past I. 2803 BasicBlock::iterator L = llvm::next(BasicBlock::iterator(I)); 2804 2805 DenseSet<Value *> Users; 2806 AliasSetTracker WriteSet(*AA); 2807 for (; cast<Instruction>(L) != J; ++L) 2808 (void) trackUsesOfI(Users, WriteSet, I, L, true, &LoadMoveSetPairs); 2809 2810 assert(cast<Instruction>(L) == J && 2811 "Tracking has not proceeded far enough to check for dependencies"); 2812 // If J is now in the use set of I, then trackUsesOfI will return true 2813 // and we have a dependency cycle (and the fusing operation must abort). 2814 return !trackUsesOfI(Users, WriteSet, I, J, true, &LoadMoveSetPairs); 2815 } 2816 2817 // Move all uses of the function I (including pairing-induced uses) after J. 2818 void BBVectorize::moveUsesOfIAfterJ(BasicBlock &BB, 2819 DenseSet<ValuePair> &LoadMoveSetPairs, 2820 Instruction *&InsertionPt, 2821 Instruction *I, Instruction *J) { 2822 // Skip to the first instruction past I. 2823 BasicBlock::iterator L = llvm::next(BasicBlock::iterator(I)); 2824 2825 DenseSet<Value *> Users; 2826 AliasSetTracker WriteSet(*AA); 2827 for (; cast<Instruction>(L) != J;) { 2828 if (trackUsesOfI(Users, WriteSet, I, L, true, &LoadMoveSetPairs)) { 2829 // Move this instruction 2830 Instruction *InstToMove = L; ++L; 2831 2832 DEBUG(dbgs() << "BBV: moving: " << *InstToMove << 2833 " to after " << *InsertionPt << "\n"); 2834 InstToMove->removeFromParent(); 2835 InstToMove->insertAfter(InsertionPt); 2836 InsertionPt = InstToMove; 2837 } else { 2838 ++L; 2839 } 2840 } 2841 } 2842 2843 // Collect all load instruction that are in the move set of a given first 2844 // pair member. These loads depend on the first instruction, I, and so need 2845 // to be moved after J (the second instruction) when the pair is fused. 2846 void BBVectorize::collectPairLoadMoveSet(BasicBlock &BB, 2847 DenseMap<Value *, Value *> &ChosenPairs, 2848 DenseMap<Value *, std::vector<Value *> > &LoadMoveSet, 2849 DenseSet<ValuePair> &LoadMoveSetPairs, 2850 Instruction *I) { 2851 // Skip to the first instruction past I. 2852 BasicBlock::iterator L = llvm::next(BasicBlock::iterator(I)); 2853 2854 DenseSet<Value *> Users; 2855 AliasSetTracker WriteSet(*AA); 2856 2857 // Note: We cannot end the loop when we reach J because J could be moved 2858 // farther down the use chain by another instruction pairing. Also, J 2859 // could be before I if this is an inverted input. 2860 for (BasicBlock::iterator E = BB.end(); cast<Instruction>(L) != E; ++L) { 2861 if (trackUsesOfI(Users, WriteSet, I, L)) { 2862 if (L->mayReadFromMemory()) { 2863 LoadMoveSet[L].push_back(I); 2864 LoadMoveSetPairs.insert(ValuePair(L, I)); 2865 } 2866 } 2867 } 2868 } 2869 2870 // In cases where both load/stores and the computation of their pointers 2871 // are chosen for vectorization, we can end up in a situation where the 2872 // aliasing analysis starts returning different query results as the 2873 // process of fusing instruction pairs continues. Because the algorithm 2874 // relies on finding the same use dags here as were found earlier, we'll 2875 // need to precompute the necessary aliasing information here and then 2876 // manually update it during the fusion process. 2877 void BBVectorize::collectLoadMoveSet(BasicBlock &BB, 2878 std::vector<Value *> &PairableInsts, 2879 DenseMap<Value *, Value *> &ChosenPairs, 2880 DenseMap<Value *, std::vector<Value *> > &LoadMoveSet, 2881 DenseSet<ValuePair> &LoadMoveSetPairs) { 2882 for (std::vector<Value *>::iterator PI = PairableInsts.begin(), 2883 PIE = PairableInsts.end(); PI != PIE; ++PI) { 2884 DenseMap<Value *, Value *>::iterator P = ChosenPairs.find(*PI); 2885 if (P == ChosenPairs.end()) continue; 2886 2887 Instruction *I = cast<Instruction>(P->first); 2888 collectPairLoadMoveSet(BB, ChosenPairs, LoadMoveSet, 2889 LoadMoveSetPairs, I); 2890 } 2891 } 2892 2893 // When the first instruction in each pair is cloned, it will inherit its 2894 // parent's metadata. This metadata must be combined with that of the other 2895 // instruction in a safe way. 2896 void BBVectorize::combineMetadata(Instruction *K, const Instruction *J) { 2897 SmallVector<std::pair<unsigned, MDNode*>, 4> Metadata; 2898 K->getAllMetadataOtherThanDebugLoc(Metadata); 2899 for (unsigned i = 0, n = Metadata.size(); i < n; ++i) { 2900 unsigned Kind = Metadata[i].first; 2901 MDNode *JMD = J->getMetadata(Kind); 2902 MDNode *KMD = Metadata[i].second; 2903 2904 switch (Kind) { 2905 default: 2906 K->setMetadata(Kind, 0); // Remove unknown metadata 2907 break; 2908 case LLVMContext::MD_tbaa: 2909 K->setMetadata(Kind, MDNode::getMostGenericTBAA(JMD, KMD)); 2910 break; 2911 case LLVMContext::MD_fpmath: 2912 K->setMetadata(Kind, MDNode::getMostGenericFPMath(JMD, KMD)); 2913 break; 2914 } 2915 } 2916 } 2917 2918 // This function fuses the chosen instruction pairs into vector instructions, 2919 // taking care preserve any needed scalar outputs and, then, it reorders the 2920 // remaining instructions as needed (users of the first member of the pair 2921 // need to be moved to after the location of the second member of the pair 2922 // because the vector instruction is inserted in the location of the pair's 2923 // second member). 2924 void BBVectorize::fuseChosenPairs(BasicBlock &BB, 2925 std::vector<Value *> &PairableInsts, 2926 DenseMap<Value *, Value *> &ChosenPairs, 2927 DenseSet<ValuePair> &FixedOrderPairs, 2928 DenseMap<VPPair, unsigned> &PairConnectionTypes, 2929 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs, 2930 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairDeps) { 2931 LLVMContext& Context = BB.getContext(); 2932 2933 // During the vectorization process, the order of the pairs to be fused 2934 // could be flipped. So we'll add each pair, flipped, into the ChosenPairs 2935 // list. After a pair is fused, the flipped pair is removed from the list. 2936 DenseSet<ValuePair> FlippedPairs; 2937 for (DenseMap<Value *, Value *>::iterator P = ChosenPairs.begin(), 2938 E = ChosenPairs.end(); P != E; ++P) 2939 FlippedPairs.insert(ValuePair(P->second, P->first)); 2940 for (DenseSet<ValuePair>::iterator P = FlippedPairs.begin(), 2941 E = FlippedPairs.end(); P != E; ++P) 2942 ChosenPairs.insert(*P); 2943 2944 DenseMap<Value *, std::vector<Value *> > LoadMoveSet; 2945 DenseSet<ValuePair> LoadMoveSetPairs; 2946 collectLoadMoveSet(BB, PairableInsts, ChosenPairs, 2947 LoadMoveSet, LoadMoveSetPairs); 2948 2949 DEBUG(dbgs() << "BBV: initial: \n" << BB << "\n"); 2950 2951 for (BasicBlock::iterator PI = BB.getFirstInsertionPt(); PI != BB.end();) { 2952 DenseMap<Value *, Value *>::iterator P = ChosenPairs.find(PI); 2953 if (P == ChosenPairs.end()) { 2954 ++PI; 2955 continue; 2956 } 2957 2958 if (getDepthFactor(P->first) == 0) { 2959 // These instructions are not really fused, but are tracked as though 2960 // they are. Any case in which it would be interesting to fuse them 2961 // will be taken care of by InstCombine. 2962 --NumFusedOps; 2963 ++PI; 2964 continue; 2965 } 2966 2967 Instruction *I = cast<Instruction>(P->first), 2968 *J = cast<Instruction>(P->second); 2969 2970 DEBUG(dbgs() << "BBV: fusing: " << *I << 2971 " <-> " << *J << "\n"); 2972 2973 // Remove the pair and flipped pair from the list. 2974 DenseMap<Value *, Value *>::iterator FP = ChosenPairs.find(P->second); 2975 assert(FP != ChosenPairs.end() && "Flipped pair not found in list"); 2976 ChosenPairs.erase(FP); 2977 ChosenPairs.erase(P); 2978 2979 if (!canMoveUsesOfIAfterJ(BB, LoadMoveSetPairs, I, J)) { 2980 DEBUG(dbgs() << "BBV: fusion of: " << *I << 2981 " <-> " << *J << 2982 " aborted because of non-trivial dependency cycle\n"); 2983 --NumFusedOps; 2984 ++PI; 2985 continue; 2986 } 2987 2988 // If the pair must have the other order, then flip it. 2989 bool FlipPairOrder = FixedOrderPairs.count(ValuePair(J, I)); 2990 if (!FlipPairOrder && !FixedOrderPairs.count(ValuePair(I, J))) { 2991 // This pair does not have a fixed order, and so we might want to 2992 // flip it if that will yield fewer shuffles. We count the number 2993 // of dependencies connected via swaps, and those directly connected, 2994 // and flip the order if the number of swaps is greater. 2995 bool OrigOrder = true; 2996 DenseMap<ValuePair, std::vector<ValuePair> >::iterator IJ = 2997 ConnectedPairDeps.find(ValuePair(I, J)); 2998 if (IJ == ConnectedPairDeps.end()) { 2999 IJ = ConnectedPairDeps.find(ValuePair(J, I)); 3000 OrigOrder = false; 3001 } 3002 3003 if (IJ != ConnectedPairDeps.end()) { 3004 unsigned NumDepsDirect = 0, NumDepsSwap = 0; 3005 for (std::vector<ValuePair>::iterator T = IJ->second.begin(), 3006 TE = IJ->second.end(); T != TE; ++T) { 3007 VPPair Q(IJ->first, *T); 3008 DenseMap<VPPair, unsigned>::iterator R = 3009 PairConnectionTypes.find(VPPair(Q.second, Q.first)); 3010 assert(R != PairConnectionTypes.end() && 3011 "Cannot find pair connection type"); 3012 if (R->second == PairConnectionDirect) 3013 ++NumDepsDirect; 3014 else if (R->second == PairConnectionSwap) 3015 ++NumDepsSwap; 3016 } 3017 3018 if (!OrigOrder) 3019 std::swap(NumDepsDirect, NumDepsSwap); 3020 3021 if (NumDepsSwap > NumDepsDirect) { 3022 FlipPairOrder = true; 3023 DEBUG(dbgs() << "BBV: reordering pair: " << *I << 3024 " <-> " << *J << "\n"); 3025 } 3026 } 3027 } 3028 3029 Instruction *L = I, *H = J; 3030 if (FlipPairOrder) 3031 std::swap(H, L); 3032 3033 // If the pair being fused uses the opposite order from that in the pair 3034 // connection map, then we need to flip the types. 3035 DenseMap<ValuePair, std::vector<ValuePair> >::iterator HL = 3036 ConnectedPairs.find(ValuePair(H, L)); 3037 if (HL != ConnectedPairs.end()) 3038 for (std::vector<ValuePair>::iterator T = HL->second.begin(), 3039 TE = HL->second.end(); T != TE; ++T) { 3040 VPPair Q(HL->first, *T); 3041 DenseMap<VPPair, unsigned>::iterator R = PairConnectionTypes.find(Q); 3042 assert(R != PairConnectionTypes.end() && 3043 "Cannot find pair connection type"); 3044 if (R->second == PairConnectionDirect) 3045 R->second = PairConnectionSwap; 3046 else if (R->second == PairConnectionSwap) 3047 R->second = PairConnectionDirect; 3048 } 3049 3050 bool LBeforeH = !FlipPairOrder; 3051 unsigned NumOperands = I->getNumOperands(); 3052 SmallVector<Value *, 3> ReplacedOperands(NumOperands); 3053 getReplacementInputsForPair(Context, L, H, ReplacedOperands, 3054 LBeforeH); 3055 3056 // Make a copy of the original operation, change its type to the vector 3057 // type and replace its operands with the vector operands. 3058 Instruction *K = L->clone(); 3059 if (L->hasName()) 3060 K->takeName(L); 3061 else if (H->hasName()) 3062 K->takeName(H); 3063 3064 if (!isa<StoreInst>(K)) 3065 K->mutateType(getVecTypeForPair(L->getType(), H->getType())); 3066 3067 combineMetadata(K, H); 3068 K->intersectOptionalDataWith(H); 3069 3070 for (unsigned o = 0; o < NumOperands; ++o) 3071 K->setOperand(o, ReplacedOperands[o]); 3072 3073 K->insertAfter(J); 3074 3075 // Instruction insertion point: 3076 Instruction *InsertionPt = K; 3077 Instruction *K1 = 0, *K2 = 0; 3078 replaceOutputsOfPair(Context, L, H, K, InsertionPt, K1, K2); 3079 3080 // The use dag of the first original instruction must be moved to after 3081 // the location of the second instruction. The entire use dag of the 3082 // first instruction is disjoint from the input dag of the second 3083 // (by definition), and so commutes with it. 3084 3085 moveUsesOfIAfterJ(BB, LoadMoveSetPairs, InsertionPt, I, J); 3086 3087 if (!isa<StoreInst>(I)) { 3088 L->replaceAllUsesWith(K1); 3089 H->replaceAllUsesWith(K2); 3090 AA->replaceWithNewValue(L, K1); 3091 AA->replaceWithNewValue(H, K2); 3092 } 3093 3094 // Instructions that may read from memory may be in the load move set. 3095 // Once an instruction is fused, we no longer need its move set, and so 3096 // the values of the map never need to be updated. However, when a load 3097 // is fused, we need to merge the entries from both instructions in the 3098 // pair in case those instructions were in the move set of some other 3099 // yet-to-be-fused pair. The loads in question are the keys of the map. 3100 if (I->mayReadFromMemory()) { 3101 std::vector<ValuePair> NewSetMembers; 3102 DenseMap<Value *, std::vector<Value *> >::iterator II = 3103 LoadMoveSet.find(I); 3104 if (II != LoadMoveSet.end()) 3105 for (std::vector<Value *>::iterator N = II->second.begin(), 3106 NE = II->second.end(); N != NE; ++N) 3107 NewSetMembers.push_back(ValuePair(K, *N)); 3108 DenseMap<Value *, std::vector<Value *> >::iterator JJ = 3109 LoadMoveSet.find(J); 3110 if (JJ != LoadMoveSet.end()) 3111 for (std::vector<Value *>::iterator N = JJ->second.begin(), 3112 NE = JJ->second.end(); N != NE; ++N) 3113 NewSetMembers.push_back(ValuePair(K, *N)); 3114 for (std::vector<ValuePair>::iterator A = NewSetMembers.begin(), 3115 AE = NewSetMembers.end(); A != AE; ++A) { 3116 LoadMoveSet[A->first].push_back(A->second); 3117 LoadMoveSetPairs.insert(*A); 3118 } 3119 } 3120 3121 // Before removing I, set the iterator to the next instruction. 3122 PI = llvm::next(BasicBlock::iterator(I)); 3123 if (cast<Instruction>(PI) == J) 3124 ++PI; 3125 3126 SE->forgetValue(I); 3127 SE->forgetValue(J); 3128 I->eraseFromParent(); 3129 J->eraseFromParent(); 3130 3131 DEBUG(if (PrintAfterEveryPair) dbgs() << "BBV: block is now: \n" << 3132 BB << "\n"); 3133 } 3134 3135 DEBUG(dbgs() << "BBV: final: \n" << BB << "\n"); 3136 } 3137 } 3138 3139 char BBVectorize::ID = 0; 3140 static const char bb_vectorize_name[] = "Basic-Block Vectorization"; 3141 INITIALIZE_PASS_BEGIN(BBVectorize, BBV_NAME, bb_vectorize_name, false, false) 3142 INITIALIZE_AG_DEPENDENCY(AliasAnalysis) 3143 INITIALIZE_AG_DEPENDENCY(TargetTransformInfo) 3144 INITIALIZE_PASS_DEPENDENCY(DominatorTree) 3145 INITIALIZE_PASS_DEPENDENCY(ScalarEvolution) 3146 INITIALIZE_PASS_END(BBVectorize, BBV_NAME, bb_vectorize_name, false, false) 3147 3148 BasicBlockPass *llvm::createBBVectorizePass(const VectorizeConfig &C) { 3149 return new BBVectorize(C); 3150 } 3151 3152 bool 3153 llvm::vectorizeBasicBlock(Pass *P, BasicBlock &BB, const VectorizeConfig &C) { 3154 BBVectorize BBVectorizer(P, C); 3155 return BBVectorizer.vectorizeBB(BB); 3156 } 3157 3158 //===----------------------------------------------------------------------===// 3159 VectorizeConfig::VectorizeConfig() { 3160 VectorBits = ::VectorBits; 3161 VectorizeBools = !::NoBools; 3162 VectorizeInts = !::NoInts; 3163 VectorizeFloats = !::NoFloats; 3164 VectorizePointers = !::NoPointers; 3165 VectorizeCasts = !::NoCasts; 3166 VectorizeMath = !::NoMath; 3167 VectorizeFMA = !::NoFMA; 3168 VectorizeSelect = !::NoSelect; 3169 VectorizeCmp = !::NoCmp; 3170 VectorizeGEP = !::NoGEP; 3171 VectorizeMemOps = !::NoMemOps; 3172 AlignedOnly = ::AlignedOnly; 3173 ReqChainDepth= ::ReqChainDepth; 3174 SearchLimit = ::SearchLimit; 3175 MaxCandPairsForCycleCheck = ::MaxCandPairsForCycleCheck; 3176 SplatBreaksChain = ::SplatBreaksChain; 3177 MaxInsts = ::MaxInsts; 3178 MaxPairs = ::MaxPairs; 3179 MaxIter = ::MaxIter; 3180 Pow2LenOnly = ::Pow2LenOnly; 3181 NoMemOpBoost = ::NoMemOpBoost; 3182 FastDep = ::FastDep; 3183 } 3184
