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/Constants.h" 20#include "llvm/DerivedTypes.h" 21#include "llvm/Function.h" 22#include "llvm/Instructions.h" 23#include "llvm/IntrinsicInst.h" 24#include "llvm/Intrinsics.h" 25#include "llvm/LLVMContext.h" 26#include "llvm/Metadata.h" 27#include "llvm/Pass.h" 28#include "llvm/Type.h" 29#include "llvm/ADT/DenseMap.h" 30#include "llvm/ADT/DenseSet.h" 31#include "llvm/ADT/SmallVector.h" 32#include "llvm/ADT/Statistic.h" 33#include "llvm/ADT/STLExtras.h" 34#include "llvm/ADT/StringExtras.h" 35#include "llvm/Analysis/AliasAnalysis.h" 36#include "llvm/Analysis/AliasSetTracker.h" 37#include "llvm/Analysis/ScalarEvolution.h" 38#include "llvm/Analysis/ScalarEvolutionExpressions.h" 39#include "llvm/Analysis/ValueTracking.h" 40#include "llvm/Support/CommandLine.h" 41#include "llvm/Support/Debug.h" 42#include "llvm/Support/raw_ostream.h" 43#include "llvm/Support/ValueHandle.h" 44#include "llvm/Target/TargetData.h" 45#include "llvm/Transforms/Utils/Local.h" 46#include "llvm/Transforms/Vectorize.h" 47#include <algorithm> 48#include <map> 49using namespace llvm; 50 51static cl::opt<unsigned> 52ReqChainDepth("bb-vectorize-req-chain-depth", cl::init(6), cl::Hidden, 53 cl::desc("The required chain depth for vectorization")); 54 55static cl::opt<unsigned> 56SearchLimit("bb-vectorize-search-limit", cl::init(400), cl::Hidden, 57 cl::desc("The maximum search distance for instruction pairs")); 58 59static cl::opt<bool> 60SplatBreaksChain("bb-vectorize-splat-breaks-chain", cl::init(false), cl::Hidden, 61 cl::desc("Replicating one element to a pair breaks the chain")); 62 63static cl::opt<unsigned> 64VectorBits("bb-vectorize-vector-bits", cl::init(128), cl::Hidden, 65 cl::desc("The size of the native vector registers")); 66 67static cl::opt<unsigned> 68MaxIter("bb-vectorize-max-iter", cl::init(0), cl::Hidden, 69 cl::desc("The maximum number of pairing iterations")); 70 71static cl::opt<bool> 72Pow2LenOnly("bb-vectorize-pow2-len-only", cl::init(false), cl::Hidden, 73 cl::desc("Don't try to form non-2^n-length vectors")); 74 75static cl::opt<unsigned> 76MaxInsts("bb-vectorize-max-instr-per-group", cl::init(500), cl::Hidden, 77 cl::desc("The maximum number of pairable instructions per group")); 78 79static cl::opt<unsigned> 80MaxCandPairsForCycleCheck("bb-vectorize-max-cycle-check-pairs", cl::init(200), 81 cl::Hidden, cl::desc("The maximum number of candidate pairs with which to use" 82 " a full cycle check")); 83 84static cl::opt<bool> 85NoBools("bb-vectorize-no-bools", cl::init(false), cl::Hidden, 86 cl::desc("Don't try to vectorize boolean (i1) values")); 87 88static cl::opt<bool> 89NoInts("bb-vectorize-no-ints", cl::init(false), cl::Hidden, 90 cl::desc("Don't try to vectorize integer values")); 91 92static cl::opt<bool> 93NoFloats("bb-vectorize-no-floats", cl::init(false), cl::Hidden, 94 cl::desc("Don't try to vectorize floating-point values")); 95 96static cl::opt<bool> 97NoPointers("bb-vectorize-no-pointers", cl::init(false), cl::Hidden, 98 cl::desc("Don't try to vectorize pointer values")); 99 100static cl::opt<bool> 101NoCasts("bb-vectorize-no-casts", cl::init(false), cl::Hidden, 102 cl::desc("Don't try to vectorize casting (conversion) operations")); 103 104static cl::opt<bool> 105NoMath("bb-vectorize-no-math", cl::init(false), cl::Hidden, 106 cl::desc("Don't try to vectorize floating-point math intrinsics")); 107 108static cl::opt<bool> 109NoFMA("bb-vectorize-no-fma", cl::init(false), cl::Hidden, 110 cl::desc("Don't try to vectorize the fused-multiply-add intrinsic")); 111 112static cl::opt<bool> 113NoSelect("bb-vectorize-no-select", cl::init(false), cl::Hidden, 114 cl::desc("Don't try to vectorize select instructions")); 115 116static cl::opt<bool> 117NoCmp("bb-vectorize-no-cmp", cl::init(false), cl::Hidden, 118 cl::desc("Don't try to vectorize comparison instructions")); 119 120static cl::opt<bool> 121NoGEP("bb-vectorize-no-gep", cl::init(false), cl::Hidden, 122 cl::desc("Don't try to vectorize getelementptr instructions")); 123 124static cl::opt<bool> 125NoMemOps("bb-vectorize-no-mem-ops", cl::init(false), cl::Hidden, 126 cl::desc("Don't try to vectorize loads and stores")); 127 128static cl::opt<bool> 129AlignedOnly("bb-vectorize-aligned-only", cl::init(false), cl::Hidden, 130 cl::desc("Only generate aligned loads and stores")); 131 132static cl::opt<bool> 133NoMemOpBoost("bb-vectorize-no-mem-op-boost", 134 cl::init(false), cl::Hidden, 135 cl::desc("Don't boost the chain-depth contribution of loads and stores")); 136 137static cl::opt<bool> 138FastDep("bb-vectorize-fast-dep", cl::init(false), cl::Hidden, 139 cl::desc("Use a fast instruction dependency analysis")); 140 141#ifndef NDEBUG 142static cl::opt<bool> 143DebugInstructionExamination("bb-vectorize-debug-instruction-examination", 144 cl::init(false), cl::Hidden, 145 cl::desc("When debugging is enabled, output information on the" 146 " instruction-examination process")); 147static cl::opt<bool> 148DebugCandidateSelection("bb-vectorize-debug-candidate-selection", 149 cl::init(false), cl::Hidden, 150 cl::desc("When debugging is enabled, output information on the" 151 " candidate-selection process")); 152static cl::opt<bool> 153DebugPairSelection("bb-vectorize-debug-pair-selection", 154 cl::init(false), cl::Hidden, 155 cl::desc("When debugging is enabled, output information on the" 156 " pair-selection process")); 157static cl::opt<bool> 158DebugCycleCheck("bb-vectorize-debug-cycle-check", 159 cl::init(false), cl::Hidden, 160 cl::desc("When debugging is enabled, output information on the" 161 " cycle-checking process")); 162#endif 163 164STATISTIC(NumFusedOps, "Number of operations fused by bb-vectorize"); 165 166namespace { 167 struct BBVectorize : public BasicBlockPass { 168 static char ID; // Pass identification, replacement for typeid 169 170 const VectorizeConfig Config; 171 172 BBVectorize(const VectorizeConfig &C = VectorizeConfig()) 173 : BasicBlockPass(ID), Config(C) { 174 initializeBBVectorizePass(*PassRegistry::getPassRegistry()); 175 } 176 177 BBVectorize(Pass *P, const VectorizeConfig &C) 178 : BasicBlockPass(ID), Config(C) { 179 AA = &P->getAnalysis<AliasAnalysis>(); 180 SE = &P->getAnalysis<ScalarEvolution>(); 181 TD = P->getAnalysisIfAvailable<TargetData>(); 182 } 183 184 typedef std::pair<Value *, Value *> ValuePair; 185 typedef std::pair<ValuePair, size_t> ValuePairWithDepth; 186 typedef std::pair<ValuePair, ValuePair> VPPair; // A ValuePair pair 187 typedef std::pair<std::multimap<Value *, Value *>::iterator, 188 std::multimap<Value *, Value *>::iterator> VPIteratorPair; 189 typedef std::pair<std::multimap<ValuePair, ValuePair>::iterator, 190 std::multimap<ValuePair, ValuePair>::iterator> 191 VPPIteratorPair; 192 193 AliasAnalysis *AA; 194 ScalarEvolution *SE; 195 TargetData *TD; 196 197 // FIXME: const correct? 198 199 bool vectorizePairs(BasicBlock &BB, bool NonPow2Len = false); 200 201 bool getCandidatePairs(BasicBlock &BB, 202 BasicBlock::iterator &Start, 203 std::multimap<Value *, Value *> &CandidatePairs, 204 std::vector<Value *> &PairableInsts, bool NonPow2Len); 205 206 void computeConnectedPairs(std::multimap<Value *, Value *> &CandidatePairs, 207 std::vector<Value *> &PairableInsts, 208 std::multimap<ValuePair, ValuePair> &ConnectedPairs); 209 210 void buildDepMap(BasicBlock &BB, 211 std::multimap<Value *, Value *> &CandidatePairs, 212 std::vector<Value *> &PairableInsts, 213 DenseSet<ValuePair> &PairableInstUsers); 214 215 void choosePairs(std::multimap<Value *, Value *> &CandidatePairs, 216 std::vector<Value *> &PairableInsts, 217 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 218 DenseSet<ValuePair> &PairableInstUsers, 219 DenseMap<Value *, Value *>& ChosenPairs); 220 221 void fuseChosenPairs(BasicBlock &BB, 222 std::vector<Value *> &PairableInsts, 223 DenseMap<Value *, Value *>& ChosenPairs); 224 225 bool isInstVectorizable(Instruction *I, bool &IsSimpleLoadStore); 226 227 bool areInstsCompatible(Instruction *I, Instruction *J, 228 bool IsSimpleLoadStore, bool NonPow2Len); 229 230 bool trackUsesOfI(DenseSet<Value *> &Users, 231 AliasSetTracker &WriteSet, Instruction *I, 232 Instruction *J, bool UpdateUsers = true, 233 std::multimap<Value *, Value *> *LoadMoveSet = 0); 234 235 void computePairsConnectedTo( 236 std::multimap<Value *, Value *> &CandidatePairs, 237 std::vector<Value *> &PairableInsts, 238 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 239 ValuePair P); 240 241 bool pairsConflict(ValuePair P, ValuePair Q, 242 DenseSet<ValuePair> &PairableInstUsers, 243 std::multimap<ValuePair, ValuePair> *PairableInstUserMap = 0); 244 245 bool pairWillFormCycle(ValuePair P, 246 std::multimap<ValuePair, ValuePair> &PairableInstUsers, 247 DenseSet<ValuePair> &CurrentPairs); 248 249 void pruneTreeFor( 250 std::multimap<Value *, Value *> &CandidatePairs, 251 std::vector<Value *> &PairableInsts, 252 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 253 DenseSet<ValuePair> &PairableInstUsers, 254 std::multimap<ValuePair, ValuePair> &PairableInstUserMap, 255 DenseMap<Value *, Value *> &ChosenPairs, 256 DenseMap<ValuePair, size_t> &Tree, 257 DenseSet<ValuePair> &PrunedTree, ValuePair J, 258 bool UseCycleCheck); 259 260 void buildInitialTreeFor( 261 std::multimap<Value *, Value *> &CandidatePairs, 262 std::vector<Value *> &PairableInsts, 263 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 264 DenseSet<ValuePair> &PairableInstUsers, 265 DenseMap<Value *, Value *> &ChosenPairs, 266 DenseMap<ValuePair, size_t> &Tree, ValuePair J); 267 268 void findBestTreeFor( 269 std::multimap<Value *, Value *> &CandidatePairs, 270 std::vector<Value *> &PairableInsts, 271 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 272 DenseSet<ValuePair> &PairableInstUsers, 273 std::multimap<ValuePair, ValuePair> &PairableInstUserMap, 274 DenseMap<Value *, Value *> &ChosenPairs, 275 DenseSet<ValuePair> &BestTree, size_t &BestMaxDepth, 276 size_t &BestEffSize, VPIteratorPair ChoiceRange, 277 bool UseCycleCheck); 278 279 Value *getReplacementPointerInput(LLVMContext& Context, Instruction *I, 280 Instruction *J, unsigned o, bool FlipMemInputs); 281 282 void fillNewShuffleMask(LLVMContext& Context, Instruction *J, 283 unsigned MaskOffset, unsigned NumInElem, 284 unsigned NumInElem1, unsigned IdxOffset, 285 std::vector<Constant*> &Mask); 286 287 Value *getReplacementShuffleMask(LLVMContext& Context, Instruction *I, 288 Instruction *J); 289 290 bool expandIEChain(LLVMContext& Context, Instruction *I, Instruction *J, 291 unsigned o, Value *&LOp, unsigned numElemL, 292 Type *ArgTypeL, Type *ArgTypeR, 293 unsigned IdxOff = 0); 294 295 Value *getReplacementInput(LLVMContext& Context, Instruction *I, 296 Instruction *J, unsigned o, bool FlipMemInputs); 297 298 void getReplacementInputsForPair(LLVMContext& Context, Instruction *I, 299 Instruction *J, SmallVector<Value *, 3> &ReplacedOperands, 300 bool FlipMemInputs); 301 302 void replaceOutputsOfPair(LLVMContext& Context, Instruction *I, 303 Instruction *J, Instruction *K, 304 Instruction *&InsertionPt, Instruction *&K1, 305 Instruction *&K2, bool FlipMemInputs); 306 307 void collectPairLoadMoveSet(BasicBlock &BB, 308 DenseMap<Value *, Value *> &ChosenPairs, 309 std::multimap<Value *, Value *> &LoadMoveSet, 310 Instruction *I); 311 312 void collectLoadMoveSet(BasicBlock &BB, 313 std::vector<Value *> &PairableInsts, 314 DenseMap<Value *, Value *> &ChosenPairs, 315 std::multimap<Value *, Value *> &LoadMoveSet); 316 317 void collectPtrInfo(std::vector<Value *> &PairableInsts, 318 DenseMap<Value *, Value *> &ChosenPairs, 319 DenseSet<Value *> &LowPtrInsts); 320 321 bool canMoveUsesOfIAfterJ(BasicBlock &BB, 322 std::multimap<Value *, Value *> &LoadMoveSet, 323 Instruction *I, Instruction *J); 324 325 void moveUsesOfIAfterJ(BasicBlock &BB, 326 std::multimap<Value *, Value *> &LoadMoveSet, 327 Instruction *&InsertionPt, 328 Instruction *I, Instruction *J); 329 330 void combineMetadata(Instruction *K, const Instruction *J); 331 332 bool vectorizeBB(BasicBlock &BB) { 333 bool changed = false; 334 // Iterate a sufficient number of times to merge types of size 1 bit, 335 // then 2 bits, then 4, etc. up to half of the target vector width of the 336 // target vector register. 337 unsigned n = 1; 338 for (unsigned v = 2; 339 v <= Config.VectorBits && (!Config.MaxIter || n <= Config.MaxIter); 340 v *= 2, ++n) { 341 DEBUG(dbgs() << "BBV: fusing loop #" << n << 342 " for " << BB.getName() << " in " << 343 BB.getParent()->getName() << "...\n"); 344 if (vectorizePairs(BB)) 345 changed = true; 346 else 347 break; 348 } 349 350 if (changed && !Pow2LenOnly) { 351 ++n; 352 for (; !Config.MaxIter || n <= Config.MaxIter; ++n) { 353 DEBUG(dbgs() << "BBV: fusing for non-2^n-length vectors loop #: " << 354 n << " for " << BB.getName() << " in " << 355 BB.getParent()->getName() << "...\n"); 356 if (!vectorizePairs(BB, true)) break; 357 } 358 } 359 360 DEBUG(dbgs() << "BBV: done!\n"); 361 return changed; 362 } 363 364 virtual bool runOnBasicBlock(BasicBlock &BB) { 365 AA = &getAnalysis<AliasAnalysis>(); 366 SE = &getAnalysis<ScalarEvolution>(); 367 TD = getAnalysisIfAvailable<TargetData>(); 368 369 return vectorizeBB(BB); 370 } 371 372 virtual void getAnalysisUsage(AnalysisUsage &AU) const { 373 BasicBlockPass::getAnalysisUsage(AU); 374 AU.addRequired<AliasAnalysis>(); 375 AU.addRequired<ScalarEvolution>(); 376 AU.addPreserved<AliasAnalysis>(); 377 AU.addPreserved<ScalarEvolution>(); 378 AU.setPreservesCFG(); 379 } 380 381 static inline VectorType *getVecTypeForPair(Type *ElemTy, Type *Elem2Ty) { 382 assert(ElemTy->getScalarType() == Elem2Ty->getScalarType() && 383 "Cannot form vector from incompatible scalar types"); 384 Type *STy = ElemTy->getScalarType(); 385 386 unsigned numElem; 387 if (VectorType *VTy = dyn_cast<VectorType>(ElemTy)) { 388 numElem = VTy->getNumElements(); 389 } else { 390 numElem = 1; 391 } 392 393 if (VectorType *VTy = dyn_cast<VectorType>(Elem2Ty)) { 394 numElem += VTy->getNumElements(); 395 } else { 396 numElem += 1; 397 } 398 399 return VectorType::get(STy, numElem); 400 } 401 402 static inline void getInstructionTypes(Instruction *I, 403 Type *&T1, Type *&T2) { 404 if (isa<StoreInst>(I)) { 405 // For stores, it is the value type, not the pointer type that matters 406 // because the value is what will come from a vector register. 407 408 Value *IVal = cast<StoreInst>(I)->getValueOperand(); 409 T1 = IVal->getType(); 410 } else { 411 T1 = I->getType(); 412 } 413 414 if (I->isCast()) 415 T2 = cast<CastInst>(I)->getSrcTy(); 416 else 417 T2 = T1; 418 } 419 420 // Returns the weight associated with the provided value. A chain of 421 // candidate pairs has a length given by the sum of the weights of its 422 // members (one weight per pair; the weight of each member of the pair 423 // is assumed to be the same). This length is then compared to the 424 // chain-length threshold to determine if a given chain is significant 425 // enough to be vectorized. The length is also used in comparing 426 // candidate chains where longer chains are considered to be better. 427 // Note: when this function returns 0, the resulting instructions are 428 // not actually fused. 429 inline size_t getDepthFactor(Value *V) { 430 // InsertElement and ExtractElement have a depth factor of zero. This is 431 // for two reasons: First, they cannot be usefully fused. Second, because 432 // the pass generates a lot of these, they can confuse the simple metric 433 // used to compare the trees in the next iteration. Thus, giving them a 434 // weight of zero allows the pass to essentially ignore them in 435 // subsequent iterations when looking for vectorization opportunities 436 // while still tracking dependency chains that flow through those 437 // instructions. 438 if (isa<InsertElementInst>(V) || isa<ExtractElementInst>(V)) 439 return 0; 440 441 // Give a load or store half of the required depth so that load/store 442 // pairs will vectorize. 443 if (!Config.NoMemOpBoost && (isa<LoadInst>(V) || isa<StoreInst>(V))) 444 return Config.ReqChainDepth/2; 445 446 return 1; 447 } 448 449 // This determines the relative offset of two loads or stores, returning 450 // true if the offset could be determined to be some constant value. 451 // For example, if OffsetInElmts == 1, then J accesses the memory directly 452 // after I; if OffsetInElmts == -1 then I accesses the memory 453 // directly after J. 454 bool getPairPtrInfo(Instruction *I, Instruction *J, 455 Value *&IPtr, Value *&JPtr, unsigned &IAlignment, unsigned &JAlignment, 456 int64_t &OffsetInElmts) { 457 OffsetInElmts = 0; 458 if (isa<LoadInst>(I)) { 459 IPtr = cast<LoadInst>(I)->getPointerOperand(); 460 JPtr = cast<LoadInst>(J)->getPointerOperand(); 461 IAlignment = cast<LoadInst>(I)->getAlignment(); 462 JAlignment = cast<LoadInst>(J)->getAlignment(); 463 } else { 464 IPtr = cast<StoreInst>(I)->getPointerOperand(); 465 JPtr = cast<StoreInst>(J)->getPointerOperand(); 466 IAlignment = cast<StoreInst>(I)->getAlignment(); 467 JAlignment = cast<StoreInst>(J)->getAlignment(); 468 } 469 470 const SCEV *IPtrSCEV = SE->getSCEV(IPtr); 471 const SCEV *JPtrSCEV = SE->getSCEV(JPtr); 472 473 // If this is a trivial offset, then we'll get something like 474 // 1*sizeof(type). With target data, which we need anyway, this will get 475 // constant folded into a number. 476 const SCEV *OffsetSCEV = SE->getMinusSCEV(JPtrSCEV, IPtrSCEV); 477 if (const SCEVConstant *ConstOffSCEV = 478 dyn_cast<SCEVConstant>(OffsetSCEV)) { 479 ConstantInt *IntOff = ConstOffSCEV->getValue(); 480 int64_t Offset = IntOff->getSExtValue(); 481 482 Type *VTy = cast<PointerType>(IPtr->getType())->getElementType(); 483 int64_t VTyTSS = (int64_t) TD->getTypeStoreSize(VTy); 484 485 Type *VTy2 = cast<PointerType>(JPtr->getType())->getElementType(); 486 if (VTy != VTy2 && Offset < 0) { 487 int64_t VTy2TSS = (int64_t) TD->getTypeStoreSize(VTy2); 488 OffsetInElmts = Offset/VTy2TSS; 489 return (abs64(Offset) % VTy2TSS) == 0; 490 } 491 492 OffsetInElmts = Offset/VTyTSS; 493 return (abs64(Offset) % VTyTSS) == 0; 494 } 495 496 return false; 497 } 498 499 // Returns true if the provided CallInst represents an intrinsic that can 500 // be vectorized. 501 bool isVectorizableIntrinsic(CallInst* I) { 502 Function *F = I->getCalledFunction(); 503 if (!F) return false; 504 505 unsigned IID = F->getIntrinsicID(); 506 if (!IID) return false; 507 508 switch(IID) { 509 default: 510 return false; 511 case Intrinsic::sqrt: 512 case Intrinsic::powi: 513 case Intrinsic::sin: 514 case Intrinsic::cos: 515 case Intrinsic::log: 516 case Intrinsic::log2: 517 case Intrinsic::log10: 518 case Intrinsic::exp: 519 case Intrinsic::exp2: 520 case Intrinsic::pow: 521 return Config.VectorizeMath; 522 case Intrinsic::fma: 523 return Config.VectorizeFMA; 524 } 525 } 526 527 // Returns true if J is the second element in some pair referenced by 528 // some multimap pair iterator pair. 529 template <typename V> 530 bool isSecondInIteratorPair(V J, std::pair< 531 typename std::multimap<V, V>::iterator, 532 typename std::multimap<V, V>::iterator> PairRange) { 533 for (typename std::multimap<V, V>::iterator K = PairRange.first; 534 K != PairRange.second; ++K) 535 if (K->second == J) return true; 536 537 return false; 538 } 539 }; 540 541 // This function implements one vectorization iteration on the provided 542 // basic block. It returns true if the block is changed. 543 bool BBVectorize::vectorizePairs(BasicBlock &BB, bool NonPow2Len) { 544 bool ShouldContinue; 545 BasicBlock::iterator Start = BB.getFirstInsertionPt(); 546 547 std::vector<Value *> AllPairableInsts; 548 DenseMap<Value *, Value *> AllChosenPairs; 549 550 do { 551 std::vector<Value *> PairableInsts; 552 std::multimap<Value *, Value *> CandidatePairs; 553 ShouldContinue = getCandidatePairs(BB, Start, CandidatePairs, 554 PairableInsts, NonPow2Len); 555 if (PairableInsts.empty()) continue; 556 557 // Now we have a map of all of the pairable instructions and we need to 558 // select the best possible pairing. A good pairing is one such that the 559 // users of the pair are also paired. This defines a (directed) forest 560 // over the pairs such that two pairs are connected iff the second pair 561 // uses the first. 562 563 // Note that it only matters that both members of the second pair use some 564 // element of the first pair (to allow for splatting). 565 566 std::multimap<ValuePair, ValuePair> ConnectedPairs; 567 computeConnectedPairs(CandidatePairs, PairableInsts, ConnectedPairs); 568 if (ConnectedPairs.empty()) continue; 569 570 // Build the pairable-instruction dependency map 571 DenseSet<ValuePair> PairableInstUsers; 572 buildDepMap(BB, CandidatePairs, PairableInsts, PairableInstUsers); 573 574 // There is now a graph of the connected pairs. For each variable, pick 575 // the pairing with the largest tree meeting the depth requirement on at 576 // least one branch. Then select all pairings that are part of that tree 577 // and remove them from the list of available pairings and pairable 578 // variables. 579 580 DenseMap<Value *, Value *> ChosenPairs; 581 choosePairs(CandidatePairs, PairableInsts, ConnectedPairs, 582 PairableInstUsers, ChosenPairs); 583 584 if (ChosenPairs.empty()) continue; 585 AllPairableInsts.insert(AllPairableInsts.end(), PairableInsts.begin(), 586 PairableInsts.end()); 587 AllChosenPairs.insert(ChosenPairs.begin(), ChosenPairs.end()); 588 } while (ShouldContinue); 589 590 if (AllChosenPairs.empty()) return false; 591 NumFusedOps += AllChosenPairs.size(); 592 593 // A set of pairs has now been selected. It is now necessary to replace the 594 // paired instructions with vector instructions. For this procedure each 595 // operand must be replaced with a vector operand. This vector is formed 596 // by using build_vector on the old operands. The replaced values are then 597 // replaced with a vector_extract on the result. Subsequent optimization 598 // passes should coalesce the build/extract combinations. 599 600 fuseChosenPairs(BB, AllPairableInsts, AllChosenPairs); 601 602 // It is important to cleanup here so that future iterations of this 603 // function have less work to do. 604 (void) SimplifyInstructionsInBlock(&BB, TD, AA->getTargetLibraryInfo()); 605 return true; 606 } 607 608 // This function returns true if the provided instruction is capable of being 609 // fused into a vector instruction. This determination is based only on the 610 // type and other attributes of the instruction. 611 bool BBVectorize::isInstVectorizable(Instruction *I, 612 bool &IsSimpleLoadStore) { 613 IsSimpleLoadStore = false; 614 615 if (CallInst *C = dyn_cast<CallInst>(I)) { 616 if (!isVectorizableIntrinsic(C)) 617 return false; 618 } else if (LoadInst *L = dyn_cast<LoadInst>(I)) { 619 // Vectorize simple loads if possbile: 620 IsSimpleLoadStore = L->isSimple(); 621 if (!IsSimpleLoadStore || !Config.VectorizeMemOps) 622 return false; 623 } else if (StoreInst *S = dyn_cast<StoreInst>(I)) { 624 // Vectorize simple stores if possbile: 625 IsSimpleLoadStore = S->isSimple(); 626 if (!IsSimpleLoadStore || !Config.VectorizeMemOps) 627 return false; 628 } else if (CastInst *C = dyn_cast<CastInst>(I)) { 629 // We can vectorize casts, but not casts of pointer types, etc. 630 if (!Config.VectorizeCasts) 631 return false; 632 633 Type *SrcTy = C->getSrcTy(); 634 if (!SrcTy->isSingleValueType()) 635 return false; 636 637 Type *DestTy = C->getDestTy(); 638 if (!DestTy->isSingleValueType()) 639 return false; 640 } else if (isa<SelectInst>(I)) { 641 if (!Config.VectorizeSelect) 642 return false; 643 } else if (isa<CmpInst>(I)) { 644 if (!Config.VectorizeCmp) 645 return false; 646 } else if (GetElementPtrInst *G = dyn_cast<GetElementPtrInst>(I)) { 647 if (!Config.VectorizeGEP) 648 return false; 649 650 // Currently, vector GEPs exist only with one index. 651 if (G->getNumIndices() != 1) 652 return false; 653 } else if (!(I->isBinaryOp() || isa<ShuffleVectorInst>(I) || 654 isa<ExtractElementInst>(I) || isa<InsertElementInst>(I))) { 655 return false; 656 } 657 658 // We can't vectorize memory operations without target data 659 if (TD == 0 && IsSimpleLoadStore) 660 return false; 661 662 Type *T1, *T2; 663 getInstructionTypes(I, T1, T2); 664 665 // Not every type can be vectorized... 666 if (!(VectorType::isValidElementType(T1) || T1->isVectorTy()) || 667 !(VectorType::isValidElementType(T2) || T2->isVectorTy())) 668 return false; 669 670 if (T1->getScalarSizeInBits() == 1 && T2->getScalarSizeInBits() == 1) { 671 if (!Config.VectorizeBools) 672 return false; 673 } else { 674 if (!Config.VectorizeInts 675 && (T1->isIntOrIntVectorTy() || T2->isIntOrIntVectorTy())) 676 return false; 677 } 678 679 if (!Config.VectorizeFloats 680 && (T1->isFPOrFPVectorTy() || T2->isFPOrFPVectorTy())) 681 return false; 682 683 // Don't vectorize target-specific types. 684 if (T1->isX86_FP80Ty() || T1->isPPC_FP128Ty() || T1->isX86_MMXTy()) 685 return false; 686 if (T2->isX86_FP80Ty() || T2->isPPC_FP128Ty() || T2->isX86_MMXTy()) 687 return false; 688 689 if ((!Config.VectorizePointers || TD == 0) && 690 (T1->getScalarType()->isPointerTy() || 691 T2->getScalarType()->isPointerTy())) 692 return false; 693 694 if (T1->getPrimitiveSizeInBits() >= Config.VectorBits || 695 T2->getPrimitiveSizeInBits() >= Config.VectorBits) 696 return false; 697 698 return true; 699 } 700 701 // This function returns true if the two provided instructions are compatible 702 // (meaning that they can be fused into a vector instruction). This assumes 703 // that I has already been determined to be vectorizable and that J is not 704 // in the use tree of I. 705 bool BBVectorize::areInstsCompatible(Instruction *I, Instruction *J, 706 bool IsSimpleLoadStore, bool NonPow2Len) { 707 DEBUG(if (DebugInstructionExamination) dbgs() << "BBV: looking at " << *I << 708 " <-> " << *J << "\n"); 709 710 // Loads and stores can be merged if they have different alignments, 711 // but are otherwise the same. 712 if (!J->isSameOperationAs(I, Instruction::CompareIgnoringAlignment | 713 (NonPow2Len ? Instruction::CompareUsingScalarTypes : 0))) 714 return false; 715 716 Type *IT1, *IT2, *JT1, *JT2; 717 getInstructionTypes(I, IT1, IT2); 718 getInstructionTypes(J, JT1, JT2); 719 unsigned MaxTypeBits = std::max( 720 IT1->getPrimitiveSizeInBits() + JT1->getPrimitiveSizeInBits(), 721 IT2->getPrimitiveSizeInBits() + JT2->getPrimitiveSizeInBits()); 722 if (MaxTypeBits > Config.VectorBits) 723 return false; 724 725 // FIXME: handle addsub-type operations! 726 727 if (IsSimpleLoadStore) { 728 Value *IPtr, *JPtr; 729 unsigned IAlignment, JAlignment; 730 int64_t OffsetInElmts = 0; 731 if (getPairPtrInfo(I, J, IPtr, JPtr, IAlignment, JAlignment, 732 OffsetInElmts) && abs64(OffsetInElmts) == 1) { 733 if (Config.AlignedOnly) { 734 Type *aTypeI = isa<StoreInst>(I) ? 735 cast<StoreInst>(I)->getValueOperand()->getType() : I->getType(); 736 Type *aTypeJ = isa<StoreInst>(J) ? 737 cast<StoreInst>(J)->getValueOperand()->getType() : J->getType(); 738 739 // An aligned load or store is possible only if the instruction 740 // with the lower offset has an alignment suitable for the 741 // vector type. 742 743 unsigned BottomAlignment = IAlignment; 744 if (OffsetInElmts < 0) BottomAlignment = JAlignment; 745 746 Type *VType = getVecTypeForPair(aTypeI, aTypeJ); 747 unsigned VecAlignment = TD->getPrefTypeAlignment(VType); 748 if (BottomAlignment < VecAlignment) 749 return false; 750 } 751 } else { 752 return false; 753 } 754 } 755 756 // The powi intrinsic is special because only the first argument is 757 // vectorized, the second arguments must be equal. 758 CallInst *CI = dyn_cast<CallInst>(I); 759 Function *FI; 760 if (CI && (FI = CI->getCalledFunction()) && 761 FI->getIntrinsicID() == Intrinsic::powi) { 762 763 Value *A1I = CI->getArgOperand(1), 764 *A1J = cast<CallInst>(J)->getArgOperand(1); 765 const SCEV *A1ISCEV = SE->getSCEV(A1I), 766 *A1JSCEV = SE->getSCEV(A1J); 767 return (A1ISCEV == A1JSCEV); 768 } 769 770 return true; 771 } 772 773 // Figure out whether or not J uses I and update the users and write-set 774 // structures associated with I. Specifically, Users represents the set of 775 // instructions that depend on I. WriteSet represents the set 776 // of memory locations that are dependent on I. If UpdateUsers is true, 777 // and J uses I, then Users is updated to contain J and WriteSet is updated 778 // to contain any memory locations to which J writes. The function returns 779 // true if J uses I. By default, alias analysis is used to determine 780 // whether J reads from memory that overlaps with a location in WriteSet. 781 // If LoadMoveSet is not null, then it is a previously-computed multimap 782 // where the key is the memory-based user instruction and the value is 783 // the instruction to be compared with I. So, if LoadMoveSet is provided, 784 // then the alias analysis is not used. This is necessary because this 785 // function is called during the process of moving instructions during 786 // vectorization and the results of the alias analysis are not stable during 787 // that process. 788 bool BBVectorize::trackUsesOfI(DenseSet<Value *> &Users, 789 AliasSetTracker &WriteSet, Instruction *I, 790 Instruction *J, bool UpdateUsers, 791 std::multimap<Value *, Value *> *LoadMoveSet) { 792 bool UsesI = false; 793 794 // This instruction may already be marked as a user due, for example, to 795 // being a member of a selected pair. 796 if (Users.count(J)) 797 UsesI = true; 798 799 if (!UsesI) 800 for (User::op_iterator JU = J->op_begin(), JE = J->op_end(); 801 JU != JE; ++JU) { 802 Value *V = *JU; 803 if (I == V || Users.count(V)) { 804 UsesI = true; 805 break; 806 } 807 } 808 if (!UsesI && J->mayReadFromMemory()) { 809 if (LoadMoveSet) { 810 VPIteratorPair JPairRange = LoadMoveSet->equal_range(J); 811 UsesI = isSecondInIteratorPair<Value*>(I, JPairRange); 812 } else { 813 for (AliasSetTracker::iterator W = WriteSet.begin(), 814 WE = WriteSet.end(); W != WE; ++W) { 815 if (W->aliasesUnknownInst(J, *AA)) { 816 UsesI = true; 817 break; 818 } 819 } 820 } 821 } 822 823 if (UsesI && UpdateUsers) { 824 if (J->mayWriteToMemory()) WriteSet.add(J); 825 Users.insert(J); 826 } 827 828 return UsesI; 829 } 830 831 // This function iterates over all instruction pairs in the provided 832 // basic block and collects all candidate pairs for vectorization. 833 bool BBVectorize::getCandidatePairs(BasicBlock &BB, 834 BasicBlock::iterator &Start, 835 std::multimap<Value *, Value *> &CandidatePairs, 836 std::vector<Value *> &PairableInsts, bool NonPow2Len) { 837 BasicBlock::iterator E = BB.end(); 838 if (Start == E) return false; 839 840 bool ShouldContinue = false, IAfterStart = false; 841 for (BasicBlock::iterator I = Start++; I != E; ++I) { 842 if (I == Start) IAfterStart = true; 843 844 bool IsSimpleLoadStore; 845 if (!isInstVectorizable(I, IsSimpleLoadStore)) continue; 846 847 // Look for an instruction with which to pair instruction *I... 848 DenseSet<Value *> Users; 849 AliasSetTracker WriteSet(*AA); 850 bool JAfterStart = IAfterStart; 851 BasicBlock::iterator J = llvm::next(I); 852 for (unsigned ss = 0; J != E && ss <= Config.SearchLimit; ++J, ++ss) { 853 if (J == Start) JAfterStart = true; 854 855 // Determine if J uses I, if so, exit the loop. 856 bool UsesI = trackUsesOfI(Users, WriteSet, I, J, !Config.FastDep); 857 if (Config.FastDep) { 858 // Note: For this heuristic to be effective, independent operations 859 // must tend to be intermixed. This is likely to be true from some 860 // kinds of grouped loop unrolling (but not the generic LLVM pass), 861 // but otherwise may require some kind of reordering pass. 862 863 // When using fast dependency analysis, 864 // stop searching after first use: 865 if (UsesI) break; 866 } else { 867 if (UsesI) continue; 868 } 869 870 // J does not use I, and comes before the first use of I, so it can be 871 // merged with I if the instructions are compatible. 872 if (!areInstsCompatible(I, J, IsSimpleLoadStore, NonPow2Len)) continue; 873 874 // J is a candidate for merging with I. 875 if (!PairableInsts.size() || 876 PairableInsts[PairableInsts.size()-1] != I) { 877 PairableInsts.push_back(I); 878 } 879 880 CandidatePairs.insert(ValuePair(I, J)); 881 882 // The next call to this function must start after the last instruction 883 // selected during this invocation. 884 if (JAfterStart) { 885 Start = llvm::next(J); 886 IAfterStart = JAfterStart = false; 887 } 888 889 DEBUG(if (DebugCandidateSelection) dbgs() << "BBV: candidate pair " 890 << *I << " <-> " << *J << "\n"); 891 892 // If we have already found too many pairs, break here and this function 893 // will be called again starting after the last instruction selected 894 // during this invocation. 895 if (PairableInsts.size() >= Config.MaxInsts) { 896 ShouldContinue = true; 897 break; 898 } 899 } 900 901 if (ShouldContinue) 902 break; 903 } 904 905 DEBUG(dbgs() << "BBV: found " << PairableInsts.size() 906 << " instructions with candidate pairs\n"); 907 908 return ShouldContinue; 909 } 910 911 // Finds candidate pairs connected to the pair P = <PI, PJ>. This means that 912 // it looks for pairs such that both members have an input which is an 913 // output of PI or PJ. 914 void BBVectorize::computePairsConnectedTo( 915 std::multimap<Value *, Value *> &CandidatePairs, 916 std::vector<Value *> &PairableInsts, 917 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 918 ValuePair P) { 919 StoreInst *SI, *SJ; 920 921 // For each possible pairing for this variable, look at the uses of 922 // the first value... 923 for (Value::use_iterator I = P.first->use_begin(), 924 E = P.first->use_end(); I != E; ++I) { 925 if (isa<LoadInst>(*I)) { 926 // A pair cannot be connected to a load because the load only takes one 927 // operand (the address) and it is a scalar even after vectorization. 928 continue; 929 } else if ((SI = dyn_cast<StoreInst>(*I)) && 930 P.first == SI->getPointerOperand()) { 931 // Similarly, a pair cannot be connected to a store through its 932 // pointer operand. 933 continue; 934 } 935 936 VPIteratorPair IPairRange = CandidatePairs.equal_range(*I); 937 938 // For each use of the first variable, look for uses of the second 939 // variable... 940 for (Value::use_iterator J = P.second->use_begin(), 941 E2 = P.second->use_end(); J != E2; ++J) { 942 if ((SJ = dyn_cast<StoreInst>(*J)) && 943 P.second == SJ->getPointerOperand()) 944 continue; 945 946 VPIteratorPair JPairRange = CandidatePairs.equal_range(*J); 947 948 // Look for <I, J>: 949 if (isSecondInIteratorPair<Value*>(*J, IPairRange)) 950 ConnectedPairs.insert(VPPair(P, ValuePair(*I, *J))); 951 952 // Look for <J, I>: 953 if (isSecondInIteratorPair<Value*>(*I, JPairRange)) 954 ConnectedPairs.insert(VPPair(P, ValuePair(*J, *I))); 955 } 956 957 if (Config.SplatBreaksChain) continue; 958 // Look for cases where just the first value in the pair is used by 959 // both members of another pair (splatting). 960 for (Value::use_iterator J = P.first->use_begin(); J != E; ++J) { 961 if ((SJ = dyn_cast<StoreInst>(*J)) && 962 P.first == SJ->getPointerOperand()) 963 continue; 964 965 if (isSecondInIteratorPair<Value*>(*J, IPairRange)) 966 ConnectedPairs.insert(VPPair(P, ValuePair(*I, *J))); 967 } 968 } 969 970 if (Config.SplatBreaksChain) return; 971 // Look for cases where just the second value in the pair is used by 972 // both members of another pair (splatting). 973 for (Value::use_iterator I = P.second->use_begin(), 974 E = P.second->use_end(); I != E; ++I) { 975 if (isa<LoadInst>(*I)) 976 continue; 977 else if ((SI = dyn_cast<StoreInst>(*I)) && 978 P.second == SI->getPointerOperand()) 979 continue; 980 981 VPIteratorPair IPairRange = CandidatePairs.equal_range(*I); 982 983 for (Value::use_iterator J = P.second->use_begin(); J != E; ++J) { 984 if ((SJ = dyn_cast<StoreInst>(*J)) && 985 P.second == SJ->getPointerOperand()) 986 continue; 987 988 if (isSecondInIteratorPair<Value*>(*J, IPairRange)) 989 ConnectedPairs.insert(VPPair(P, ValuePair(*I, *J))); 990 } 991 } 992 } 993 994 // This function figures out which pairs are connected. Two pairs are 995 // connected if some output of the first pair forms an input to both members 996 // of the second pair. 997 void BBVectorize::computeConnectedPairs( 998 std::multimap<Value *, Value *> &CandidatePairs, 999 std::vector<Value *> &PairableInsts, 1000 std::multimap<ValuePair, ValuePair> &ConnectedPairs) { 1001 1002 for (std::vector<Value *>::iterator PI = PairableInsts.begin(), 1003 PE = PairableInsts.end(); PI != PE; ++PI) { 1004 VPIteratorPair choiceRange = CandidatePairs.equal_range(*PI); 1005 1006 for (std::multimap<Value *, Value *>::iterator P = choiceRange.first; 1007 P != choiceRange.second; ++P) 1008 computePairsConnectedTo(CandidatePairs, PairableInsts, 1009 ConnectedPairs, *P); 1010 } 1011 1012 DEBUG(dbgs() << "BBV: found " << ConnectedPairs.size() 1013 << " pair connections.\n"); 1014 } 1015 1016 // This function builds a set of use tuples such that <A, B> is in the set 1017 // if B is in the use tree of A. If B is in the use tree of A, then B 1018 // depends on the output of A. 1019 void BBVectorize::buildDepMap( 1020 BasicBlock &BB, 1021 std::multimap<Value *, Value *> &CandidatePairs, 1022 std::vector<Value *> &PairableInsts, 1023 DenseSet<ValuePair> &PairableInstUsers) { 1024 DenseSet<Value *> IsInPair; 1025 for (std::multimap<Value *, Value *>::iterator C = CandidatePairs.begin(), 1026 E = CandidatePairs.end(); C != E; ++C) { 1027 IsInPair.insert(C->first); 1028 IsInPair.insert(C->second); 1029 } 1030 1031 // Iterate through the basic block, recording all Users of each 1032 // pairable instruction. 1033 1034 BasicBlock::iterator E = BB.end(); 1035 for (BasicBlock::iterator I = BB.getFirstInsertionPt(); I != E; ++I) { 1036 if (IsInPair.find(I) == IsInPair.end()) continue; 1037 1038 DenseSet<Value *> Users; 1039 AliasSetTracker WriteSet(*AA); 1040 for (BasicBlock::iterator J = llvm::next(I); J != E; ++J) 1041 (void) trackUsesOfI(Users, WriteSet, I, J); 1042 1043 for (DenseSet<Value *>::iterator U = Users.begin(), E = Users.end(); 1044 U != E; ++U) 1045 PairableInstUsers.insert(ValuePair(I, *U)); 1046 } 1047 } 1048 1049 // Returns true if an input to pair P is an output of pair Q and also an 1050 // input of pair Q is an output of pair P. If this is the case, then these 1051 // two pairs cannot be simultaneously fused. 1052 bool BBVectorize::pairsConflict(ValuePair P, ValuePair Q, 1053 DenseSet<ValuePair> &PairableInstUsers, 1054 std::multimap<ValuePair, ValuePair> *PairableInstUserMap) { 1055 // Two pairs are in conflict if they are mutual Users of eachother. 1056 bool QUsesP = PairableInstUsers.count(ValuePair(P.first, Q.first)) || 1057 PairableInstUsers.count(ValuePair(P.first, Q.second)) || 1058 PairableInstUsers.count(ValuePair(P.second, Q.first)) || 1059 PairableInstUsers.count(ValuePair(P.second, Q.second)); 1060 bool PUsesQ = PairableInstUsers.count(ValuePair(Q.first, P.first)) || 1061 PairableInstUsers.count(ValuePair(Q.first, P.second)) || 1062 PairableInstUsers.count(ValuePair(Q.second, P.first)) || 1063 PairableInstUsers.count(ValuePair(Q.second, P.second)); 1064 if (PairableInstUserMap) { 1065 // FIXME: The expensive part of the cycle check is not so much the cycle 1066 // check itself but this edge insertion procedure. This needs some 1067 // profiling and probably a different data structure (same is true of 1068 // most uses of std::multimap). 1069 if (PUsesQ) { 1070 VPPIteratorPair QPairRange = PairableInstUserMap->equal_range(Q); 1071 if (!isSecondInIteratorPair(P, QPairRange)) 1072 PairableInstUserMap->insert(VPPair(Q, P)); 1073 } 1074 if (QUsesP) { 1075 VPPIteratorPair PPairRange = PairableInstUserMap->equal_range(P); 1076 if (!isSecondInIteratorPair(Q, PPairRange)) 1077 PairableInstUserMap->insert(VPPair(P, Q)); 1078 } 1079 } 1080 1081 return (QUsesP && PUsesQ); 1082 } 1083 1084 // This function walks the use graph of current pairs to see if, starting 1085 // from P, the walk returns to P. 1086 bool BBVectorize::pairWillFormCycle(ValuePair P, 1087 std::multimap<ValuePair, ValuePair> &PairableInstUserMap, 1088 DenseSet<ValuePair> &CurrentPairs) { 1089 DEBUG(if (DebugCycleCheck) 1090 dbgs() << "BBV: starting cycle check for : " << *P.first << " <-> " 1091 << *P.second << "\n"); 1092 // A lookup table of visisted pairs is kept because the PairableInstUserMap 1093 // contains non-direct associations. 1094 DenseSet<ValuePair> Visited; 1095 SmallVector<ValuePair, 32> Q; 1096 // General depth-first post-order traversal: 1097 Q.push_back(P); 1098 do { 1099 ValuePair QTop = Q.pop_back_val(); 1100 Visited.insert(QTop); 1101 1102 DEBUG(if (DebugCycleCheck) 1103 dbgs() << "BBV: cycle check visiting: " << *QTop.first << " <-> " 1104 << *QTop.second << "\n"); 1105 VPPIteratorPair QPairRange = PairableInstUserMap.equal_range(QTop); 1106 for (std::multimap<ValuePair, ValuePair>::iterator C = QPairRange.first; 1107 C != QPairRange.second; ++C) { 1108 if (C->second == P) { 1109 DEBUG(dbgs() 1110 << "BBV: rejected to prevent non-trivial cycle formation: " 1111 << *C->first.first << " <-> " << *C->first.second << "\n"); 1112 return true; 1113 } 1114 1115 if (CurrentPairs.count(C->second) && !Visited.count(C->second)) 1116 Q.push_back(C->second); 1117 } 1118 } while (!Q.empty()); 1119 1120 return false; 1121 } 1122 1123 // This function builds the initial tree of connected pairs with the 1124 // pair J at the root. 1125 void BBVectorize::buildInitialTreeFor( 1126 std::multimap<Value *, Value *> &CandidatePairs, 1127 std::vector<Value *> &PairableInsts, 1128 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 1129 DenseSet<ValuePair> &PairableInstUsers, 1130 DenseMap<Value *, Value *> &ChosenPairs, 1131 DenseMap<ValuePair, size_t> &Tree, ValuePair J) { 1132 // Each of these pairs is viewed as the root node of a Tree. The Tree 1133 // is then walked (depth-first). As this happens, we keep track of 1134 // the pairs that compose the Tree and the maximum depth of the Tree. 1135 SmallVector<ValuePairWithDepth, 32> Q; 1136 // General depth-first post-order traversal: 1137 Q.push_back(ValuePairWithDepth(J, getDepthFactor(J.first))); 1138 do { 1139 ValuePairWithDepth QTop = Q.back(); 1140 1141 // Push each child onto the queue: 1142 bool MoreChildren = false; 1143 size_t MaxChildDepth = QTop.second; 1144 VPPIteratorPair qtRange = ConnectedPairs.equal_range(QTop.first); 1145 for (std::multimap<ValuePair, ValuePair>::iterator k = qtRange.first; 1146 k != qtRange.second; ++k) { 1147 // Make sure that this child pair is still a candidate: 1148 bool IsStillCand = false; 1149 VPIteratorPair checkRange = 1150 CandidatePairs.equal_range(k->second.first); 1151 for (std::multimap<Value *, Value *>::iterator m = checkRange.first; 1152 m != checkRange.second; ++m) { 1153 if (m->second == k->second.second) { 1154 IsStillCand = true; 1155 break; 1156 } 1157 } 1158 1159 if (IsStillCand) { 1160 DenseMap<ValuePair, size_t>::iterator C = Tree.find(k->second); 1161 if (C == Tree.end()) { 1162 size_t d = getDepthFactor(k->second.first); 1163 Q.push_back(ValuePairWithDepth(k->second, QTop.second+d)); 1164 MoreChildren = true; 1165 } else { 1166 MaxChildDepth = std::max(MaxChildDepth, C->second); 1167 } 1168 } 1169 } 1170 1171 if (!MoreChildren) { 1172 // Record the current pair as part of the Tree: 1173 Tree.insert(ValuePairWithDepth(QTop.first, MaxChildDepth)); 1174 Q.pop_back(); 1175 } 1176 } while (!Q.empty()); 1177 } 1178 1179 // Given some initial tree, prune it by removing conflicting pairs (pairs 1180 // that cannot be simultaneously chosen for vectorization). 1181 void BBVectorize::pruneTreeFor( 1182 std::multimap<Value *, Value *> &CandidatePairs, 1183 std::vector<Value *> &PairableInsts, 1184 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 1185 DenseSet<ValuePair> &PairableInstUsers, 1186 std::multimap<ValuePair, ValuePair> &PairableInstUserMap, 1187 DenseMap<Value *, Value *> &ChosenPairs, 1188 DenseMap<ValuePair, size_t> &Tree, 1189 DenseSet<ValuePair> &PrunedTree, ValuePair J, 1190 bool UseCycleCheck) { 1191 SmallVector<ValuePairWithDepth, 32> Q; 1192 // General depth-first post-order traversal: 1193 Q.push_back(ValuePairWithDepth(J, getDepthFactor(J.first))); 1194 do { 1195 ValuePairWithDepth QTop = Q.pop_back_val(); 1196 PrunedTree.insert(QTop.first); 1197 1198 // Visit each child, pruning as necessary... 1199 DenseMap<ValuePair, size_t> BestChildren; 1200 VPPIteratorPair QTopRange = ConnectedPairs.equal_range(QTop.first); 1201 for (std::multimap<ValuePair, ValuePair>::iterator K = QTopRange.first; 1202 K != QTopRange.second; ++K) { 1203 DenseMap<ValuePair, size_t>::iterator C = Tree.find(K->second); 1204 if (C == Tree.end()) continue; 1205 1206 // This child is in the Tree, now we need to make sure it is the 1207 // best of any conflicting children. There could be multiple 1208 // conflicting children, so first, determine if we're keeping 1209 // this child, then delete conflicting children as necessary. 1210 1211 // It is also necessary to guard against pairing-induced 1212 // dependencies. Consider instructions a .. x .. y .. b 1213 // such that (a,b) are to be fused and (x,y) are to be fused 1214 // but a is an input to x and b is an output from y. This 1215 // means that y cannot be moved after b but x must be moved 1216 // after b for (a,b) to be fused. In other words, after 1217 // fusing (a,b) we have y .. a/b .. x where y is an input 1218 // to a/b and x is an output to a/b: x and y can no longer 1219 // be legally fused. To prevent this condition, we must 1220 // make sure that a child pair added to the Tree is not 1221 // both an input and output of an already-selected pair. 1222 1223 // Pairing-induced dependencies can also form from more complicated 1224 // cycles. The pair vs. pair conflicts are easy to check, and so 1225 // that is done explicitly for "fast rejection", and because for 1226 // child vs. child conflicts, we may prefer to keep the current 1227 // pair in preference to the already-selected child. 1228 DenseSet<ValuePair> CurrentPairs; 1229 1230 bool CanAdd = true; 1231 for (DenseMap<ValuePair, size_t>::iterator C2 1232 = BestChildren.begin(), E2 = BestChildren.end(); 1233 C2 != E2; ++C2) { 1234 if (C2->first.first == C->first.first || 1235 C2->first.first == C->first.second || 1236 C2->first.second == C->first.first || 1237 C2->first.second == C->first.second || 1238 pairsConflict(C2->first, C->first, PairableInstUsers, 1239 UseCycleCheck ? &PairableInstUserMap : 0)) { 1240 if (C2->second >= C->second) { 1241 CanAdd = false; 1242 break; 1243 } 1244 1245 CurrentPairs.insert(C2->first); 1246 } 1247 } 1248 if (!CanAdd) continue; 1249 1250 // Even worse, this child could conflict with another node already 1251 // selected for the Tree. If that is the case, ignore this child. 1252 for (DenseSet<ValuePair>::iterator T = PrunedTree.begin(), 1253 E2 = PrunedTree.end(); T != E2; ++T) { 1254 if (T->first == C->first.first || 1255 T->first == C->first.second || 1256 T->second == C->first.first || 1257 T->second == C->first.second || 1258 pairsConflict(*T, C->first, PairableInstUsers, 1259 UseCycleCheck ? &PairableInstUserMap : 0)) { 1260 CanAdd = false; 1261 break; 1262 } 1263 1264 CurrentPairs.insert(*T); 1265 } 1266 if (!CanAdd) continue; 1267 1268 // And check the queue too... 1269 for (SmallVector<ValuePairWithDepth, 32>::iterator C2 = Q.begin(), 1270 E2 = Q.end(); C2 != E2; ++C2) { 1271 if (C2->first.first == C->first.first || 1272 C2->first.first == C->first.second || 1273 C2->first.second == C->first.first || 1274 C2->first.second == C->first.second || 1275 pairsConflict(C2->first, C->first, PairableInstUsers, 1276 UseCycleCheck ? &PairableInstUserMap : 0)) { 1277 CanAdd = false; 1278 break; 1279 } 1280 1281 CurrentPairs.insert(C2->first); 1282 } 1283 if (!CanAdd) continue; 1284 1285 // Last but not least, check for a conflict with any of the 1286 // already-chosen pairs. 1287 for (DenseMap<Value *, Value *>::iterator C2 = 1288 ChosenPairs.begin(), E2 = ChosenPairs.end(); 1289 C2 != E2; ++C2) { 1290 if (pairsConflict(*C2, C->first, PairableInstUsers, 1291 UseCycleCheck ? &PairableInstUserMap : 0)) { 1292 CanAdd = false; 1293 break; 1294 } 1295 1296 CurrentPairs.insert(*C2); 1297 } 1298 if (!CanAdd) continue; 1299 1300 // To check for non-trivial cycles formed by the addition of the 1301 // current pair we've formed a list of all relevant pairs, now use a 1302 // graph walk to check for a cycle. We start from the current pair and 1303 // walk the use tree to see if we again reach the current pair. If we 1304 // do, then the current pair is rejected. 1305 1306 // FIXME: It may be more efficient to use a topological-ordering 1307 // algorithm to improve the cycle check. This should be investigated. 1308 if (UseCycleCheck && 1309 pairWillFormCycle(C->first, PairableInstUserMap, CurrentPairs)) 1310 continue; 1311 1312 // This child can be added, but we may have chosen it in preference 1313 // to an already-selected child. Check for this here, and if a 1314 // conflict is found, then remove the previously-selected child 1315 // before adding this one in its place. 1316 for (DenseMap<ValuePair, size_t>::iterator C2 1317 = BestChildren.begin(); C2 != BestChildren.end();) { 1318 if (C2->first.first == C->first.first || 1319 C2->first.first == C->first.second || 1320 C2->first.second == C->first.first || 1321 C2->first.second == C->first.second || 1322 pairsConflict(C2->first, C->first, PairableInstUsers)) 1323 BestChildren.erase(C2++); 1324 else 1325 ++C2; 1326 } 1327 1328 BestChildren.insert(ValuePairWithDepth(C->first, C->second)); 1329 } 1330 1331 for (DenseMap<ValuePair, size_t>::iterator C 1332 = BestChildren.begin(), E2 = BestChildren.end(); 1333 C != E2; ++C) { 1334 size_t DepthF = getDepthFactor(C->first.first); 1335 Q.push_back(ValuePairWithDepth(C->first, QTop.second+DepthF)); 1336 } 1337 } while (!Q.empty()); 1338 } 1339 1340 // This function finds the best tree of mututally-compatible connected 1341 // pairs, given the choice of root pairs as an iterator range. 1342 void BBVectorize::findBestTreeFor( 1343 std::multimap<Value *, Value *> &CandidatePairs, 1344 std::vector<Value *> &PairableInsts, 1345 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 1346 DenseSet<ValuePair> &PairableInstUsers, 1347 std::multimap<ValuePair, ValuePair> &PairableInstUserMap, 1348 DenseMap<Value *, Value *> &ChosenPairs, 1349 DenseSet<ValuePair> &BestTree, size_t &BestMaxDepth, 1350 size_t &BestEffSize, VPIteratorPair ChoiceRange, 1351 bool UseCycleCheck) { 1352 for (std::multimap<Value *, Value *>::iterator J = ChoiceRange.first; 1353 J != ChoiceRange.second; ++J) { 1354 1355 // Before going any further, make sure that this pair does not 1356 // conflict with any already-selected pairs (see comment below 1357 // near the Tree pruning for more details). 1358 DenseSet<ValuePair> ChosenPairSet; 1359 bool DoesConflict = false; 1360 for (DenseMap<Value *, Value *>::iterator C = ChosenPairs.begin(), 1361 E = ChosenPairs.end(); C != E; ++C) { 1362 if (pairsConflict(*C, *J, PairableInstUsers, 1363 UseCycleCheck ? &PairableInstUserMap : 0)) { 1364 DoesConflict = true; 1365 break; 1366 } 1367 1368 ChosenPairSet.insert(*C); 1369 } 1370 if (DoesConflict) continue; 1371 1372 if (UseCycleCheck && 1373 pairWillFormCycle(*J, PairableInstUserMap, ChosenPairSet)) 1374 continue; 1375 1376 DenseMap<ValuePair, size_t> Tree; 1377 buildInitialTreeFor(CandidatePairs, PairableInsts, ConnectedPairs, 1378 PairableInstUsers, ChosenPairs, Tree, *J); 1379 1380 // Because we'll keep the child with the largest depth, the largest 1381 // depth is still the same in the unpruned Tree. 1382 size_t MaxDepth = Tree.lookup(*J); 1383 1384 DEBUG(if (DebugPairSelection) dbgs() << "BBV: found Tree for pair {" 1385 << *J->first << " <-> " << *J->second << "} of depth " << 1386 MaxDepth << " and size " << Tree.size() << "\n"); 1387 1388 // At this point the Tree has been constructed, but, may contain 1389 // contradictory children (meaning that different children of 1390 // some tree node may be attempting to fuse the same instruction). 1391 // So now we walk the tree again, in the case of a conflict, 1392 // keep only the child with the largest depth. To break a tie, 1393 // favor the first child. 1394 1395 DenseSet<ValuePair> PrunedTree; 1396 pruneTreeFor(CandidatePairs, PairableInsts, ConnectedPairs, 1397 PairableInstUsers, PairableInstUserMap, ChosenPairs, Tree, 1398 PrunedTree, *J, UseCycleCheck); 1399 1400 size_t EffSize = 0; 1401 for (DenseSet<ValuePair>::iterator S = PrunedTree.begin(), 1402 E = PrunedTree.end(); S != E; ++S) 1403 EffSize += getDepthFactor(S->first); 1404 1405 DEBUG(if (DebugPairSelection) 1406 dbgs() << "BBV: found pruned Tree for pair {" 1407 << *J->first << " <-> " << *J->second << "} of depth " << 1408 MaxDepth << " and size " << PrunedTree.size() << 1409 " (effective size: " << EffSize << ")\n"); 1410 if (MaxDepth >= Config.ReqChainDepth && EffSize > BestEffSize) { 1411 BestMaxDepth = MaxDepth; 1412 BestEffSize = EffSize; 1413 BestTree = PrunedTree; 1414 } 1415 } 1416 } 1417 1418 // Given the list of candidate pairs, this function selects those 1419 // that will be fused into vector instructions. 1420 void BBVectorize::choosePairs( 1421 std::multimap<Value *, Value *> &CandidatePairs, 1422 std::vector<Value *> &PairableInsts, 1423 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 1424 DenseSet<ValuePair> &PairableInstUsers, 1425 DenseMap<Value *, Value *>& ChosenPairs) { 1426 bool UseCycleCheck = 1427 CandidatePairs.size() <= Config.MaxCandPairsForCycleCheck; 1428 std::multimap<ValuePair, ValuePair> PairableInstUserMap; 1429 for (std::vector<Value *>::iterator I = PairableInsts.begin(), 1430 E = PairableInsts.end(); I != E; ++I) { 1431 // The number of possible pairings for this variable: 1432 size_t NumChoices = CandidatePairs.count(*I); 1433 if (!NumChoices) continue; 1434 1435 VPIteratorPair ChoiceRange = CandidatePairs.equal_range(*I); 1436 1437 // The best pair to choose and its tree: 1438 size_t BestMaxDepth = 0, BestEffSize = 0; 1439 DenseSet<ValuePair> BestTree; 1440 findBestTreeFor(CandidatePairs, PairableInsts, ConnectedPairs, 1441 PairableInstUsers, PairableInstUserMap, ChosenPairs, 1442 BestTree, BestMaxDepth, BestEffSize, ChoiceRange, 1443 UseCycleCheck); 1444 1445 // A tree has been chosen (or not) at this point. If no tree was 1446 // chosen, then this instruction, I, cannot be paired (and is no longer 1447 // considered). 1448 1449 DEBUG(if (BestTree.size() > 0) 1450 dbgs() << "BBV: selected pairs in the best tree for: " 1451 << *cast<Instruction>(*I) << "\n"); 1452 1453 for (DenseSet<ValuePair>::iterator S = BestTree.begin(), 1454 SE2 = BestTree.end(); S != SE2; ++S) { 1455 // Insert the members of this tree into the list of chosen pairs. 1456 ChosenPairs.insert(ValuePair(S->first, S->second)); 1457 DEBUG(dbgs() << "BBV: selected pair: " << *S->first << " <-> " << 1458 *S->second << "\n"); 1459 1460 // Remove all candidate pairs that have values in the chosen tree. 1461 for (std::multimap<Value *, Value *>::iterator K = 1462 CandidatePairs.begin(); K != CandidatePairs.end();) { 1463 if (K->first == S->first || K->second == S->first || 1464 K->second == S->second || K->first == S->second) { 1465 // Don't remove the actual pair chosen so that it can be used 1466 // in subsequent tree selections. 1467 if (!(K->first == S->first && K->second == S->second)) 1468 CandidatePairs.erase(K++); 1469 else 1470 ++K; 1471 } else { 1472 ++K; 1473 } 1474 } 1475 } 1476 } 1477 1478 DEBUG(dbgs() << "BBV: selected " << ChosenPairs.size() << " pairs.\n"); 1479 } 1480 1481 std::string getReplacementName(Instruction *I, bool IsInput, unsigned o, 1482 unsigned n = 0) { 1483 if (!I->hasName()) 1484 return ""; 1485 1486 return (I->getName() + (IsInput ? ".v.i" : ".v.r") + utostr(o) + 1487 (n > 0 ? "." + utostr(n) : "")).str(); 1488 } 1489 1490 // Returns the value that is to be used as the pointer input to the vector 1491 // instruction that fuses I with J. 1492 Value *BBVectorize::getReplacementPointerInput(LLVMContext& Context, 1493 Instruction *I, Instruction *J, unsigned o, 1494 bool FlipMemInputs) { 1495 Value *IPtr, *JPtr; 1496 unsigned IAlignment, JAlignment; 1497 int64_t OffsetInElmts; 1498 1499 // Note: the analysis might fail here, that is why FlipMemInputs has 1500 // been precomputed (OffsetInElmts must be unused here). 1501 (void) getPairPtrInfo(I, J, IPtr, JPtr, IAlignment, JAlignment, 1502 OffsetInElmts); 1503 1504 // The pointer value is taken to be the one with the lowest offset. 1505 Value *VPtr; 1506 if (!FlipMemInputs) { 1507 VPtr = IPtr; 1508 } else { 1509 VPtr = JPtr; 1510 } 1511 1512 Type *ArgTypeI = cast<PointerType>(IPtr->getType())->getElementType(); 1513 Type *ArgTypeJ = cast<PointerType>(JPtr->getType())->getElementType(); 1514 Type *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ); 1515 Type *VArgPtrType = PointerType::get(VArgType, 1516 cast<PointerType>(IPtr->getType())->getAddressSpace()); 1517 return new BitCastInst(VPtr, VArgPtrType, getReplacementName(I, true, o), 1518 /* insert before */ FlipMemInputs ? J : I); 1519 } 1520 1521 void BBVectorize::fillNewShuffleMask(LLVMContext& Context, Instruction *J, 1522 unsigned MaskOffset, unsigned NumInElem, 1523 unsigned NumInElem1, unsigned IdxOffset, 1524 std::vector<Constant*> &Mask) { 1525 unsigned NumElem1 = cast<VectorType>(J->getType())->getNumElements(); 1526 for (unsigned v = 0; v < NumElem1; ++v) { 1527 int m = cast<ShuffleVectorInst>(J)->getMaskValue(v); 1528 if (m < 0) { 1529 Mask[v+MaskOffset] = UndefValue::get(Type::getInt32Ty(Context)); 1530 } else { 1531 unsigned mm = m + (int) IdxOffset; 1532 if (m >= (int) NumInElem1) 1533 mm += (int) NumInElem; 1534 1535 Mask[v+MaskOffset] = 1536 ConstantInt::get(Type::getInt32Ty(Context), mm); 1537 } 1538 } 1539 } 1540 1541 // Returns the value that is to be used as the vector-shuffle mask to the 1542 // vector instruction that fuses I with J. 1543 Value *BBVectorize::getReplacementShuffleMask(LLVMContext& Context, 1544 Instruction *I, Instruction *J) { 1545 // This is the shuffle mask. We need to append the second 1546 // mask to the first, and the numbers need to be adjusted. 1547 1548 Type *ArgTypeI = I->getType(); 1549 Type *ArgTypeJ = J->getType(); 1550 Type *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ); 1551 1552 unsigned NumElemI = cast<VectorType>(ArgTypeI)->getNumElements(); 1553 1554 // Get the total number of elements in the fused vector type. 1555 // By definition, this must equal the number of elements in 1556 // the final mask. 1557 unsigned NumElem = cast<VectorType>(VArgType)->getNumElements(); 1558 std::vector<Constant*> Mask(NumElem); 1559 1560 Type *OpTypeI = I->getOperand(0)->getType(); 1561 unsigned NumInElemI = cast<VectorType>(OpTypeI)->getNumElements(); 1562 Type *OpTypeJ = J->getOperand(0)->getType(); 1563 unsigned NumInElemJ = cast<VectorType>(OpTypeJ)->getNumElements(); 1564 1565 // The fused vector will be: 1566 // ----------------------------------------------------- 1567 // | NumInElemI | NumInElemJ | NumInElemI | NumInElemJ | 1568 // ----------------------------------------------------- 1569 // from which we'll extract NumElem total elements (where the first NumElemI 1570 // of them come from the mask in I and the remainder come from the mask 1571 // in J. 1572 1573 // For the mask from the first pair... 1574 fillNewShuffleMask(Context, I, 0, NumInElemJ, NumInElemI, 1575 0, Mask); 1576 1577 // For the mask from the second pair... 1578 fillNewShuffleMask(Context, J, NumElemI, NumInElemI, NumInElemJ, 1579 NumInElemI, Mask); 1580 1581 return ConstantVector::get(Mask); 1582 } 1583 1584 bool BBVectorize::expandIEChain(LLVMContext& Context, Instruction *I, 1585 Instruction *J, unsigned o, Value *&LOp, 1586 unsigned numElemL, 1587 Type *ArgTypeL, Type *ArgTypeH, 1588 unsigned IdxOff) { 1589 bool ExpandedIEChain = false; 1590 if (InsertElementInst *LIE = dyn_cast<InsertElementInst>(LOp)) { 1591 // If we have a pure insertelement chain, then this can be rewritten 1592 // into a chain that directly builds the larger type. 1593 bool PureChain = true; 1594 InsertElementInst *LIENext = LIE; 1595 do { 1596 if (!isa<UndefValue>(LIENext->getOperand(0)) && 1597 !isa<InsertElementInst>(LIENext->getOperand(0))) { 1598 PureChain = false; 1599 break; 1600 } 1601 } while ((LIENext = 1602 dyn_cast<InsertElementInst>(LIENext->getOperand(0)))); 1603 1604 if (PureChain) { 1605 SmallVector<Value *, 8> VectElemts(numElemL, 1606 UndefValue::get(ArgTypeL->getScalarType())); 1607 InsertElementInst *LIENext = LIE; 1608 do { 1609 unsigned Idx = 1610 cast<ConstantInt>(LIENext->getOperand(2))->getSExtValue(); 1611 VectElemts[Idx] = LIENext->getOperand(1); 1612 } while ((LIENext = 1613 dyn_cast<InsertElementInst>(LIENext->getOperand(0)))); 1614 1615 LIENext = 0; 1616 Value *LIEPrev = UndefValue::get(ArgTypeH); 1617 for (unsigned i = 0; i < numElemL; ++i) { 1618 if (isa<UndefValue>(VectElemts[i])) continue; 1619 LIENext = InsertElementInst::Create(LIEPrev, VectElemts[i], 1620 ConstantInt::get(Type::getInt32Ty(Context), 1621 i + IdxOff), 1622 getReplacementName(I, true, o, i+1)); 1623 LIENext->insertBefore(J); 1624 LIEPrev = LIENext; 1625 } 1626 1627 LOp = LIENext ? (Value*) LIENext : UndefValue::get(ArgTypeH); 1628 ExpandedIEChain = true; 1629 } 1630 } 1631 1632 return ExpandedIEChain; 1633 } 1634 1635 // Returns the value to be used as the specified operand of the vector 1636 // instruction that fuses I with J. 1637 Value *BBVectorize::getReplacementInput(LLVMContext& Context, Instruction *I, 1638 Instruction *J, unsigned o, bool FlipMemInputs) { 1639 Value *CV0 = ConstantInt::get(Type::getInt32Ty(Context), 0); 1640 Value *CV1 = ConstantInt::get(Type::getInt32Ty(Context), 1); 1641 1642 // Compute the fused vector type for this operand 1643 Type *ArgTypeI = I->getOperand(o)->getType(); 1644 Type *ArgTypeJ = J->getOperand(o)->getType(); 1645 VectorType *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ); 1646 1647 Instruction *L = I, *H = J; 1648 Type *ArgTypeL = ArgTypeI, *ArgTypeH = ArgTypeJ; 1649 if (FlipMemInputs) { 1650 L = J; 1651 H = I; 1652 ArgTypeL = ArgTypeJ; 1653 ArgTypeH = ArgTypeI; 1654 } 1655 1656 unsigned numElemL; 1657 if (ArgTypeL->isVectorTy()) 1658 numElemL = cast<VectorType>(ArgTypeL)->getNumElements(); 1659 else 1660 numElemL = 1; 1661 1662 unsigned numElemH; 1663 if (ArgTypeH->isVectorTy()) 1664 numElemH = cast<VectorType>(ArgTypeH)->getNumElements(); 1665 else 1666 numElemH = 1; 1667 1668 Value *LOp = L->getOperand(o); 1669 Value *HOp = H->getOperand(o); 1670 unsigned numElem = VArgType->getNumElements(); 1671 1672 // First, we check if we can reuse the "original" vector outputs (if these 1673 // exist). We might need a shuffle. 1674 ExtractElementInst *LEE = dyn_cast<ExtractElementInst>(LOp); 1675 ExtractElementInst *HEE = dyn_cast<ExtractElementInst>(HOp); 1676 ShuffleVectorInst *LSV = dyn_cast<ShuffleVectorInst>(LOp); 1677 ShuffleVectorInst *HSV = dyn_cast<ShuffleVectorInst>(HOp); 1678 1679 // FIXME: If we're fusing shuffle instructions, then we can't apply this 1680 // optimization. The input vectors to the shuffle might be a different 1681 // length from the shuffle outputs. Unfortunately, the replacement 1682 // shuffle mask has already been formed, and the mask entries are sensitive 1683 // to the sizes of the inputs. 1684 bool IsSizeChangeShuffle = 1685 isa<ShuffleVectorInst>(L) && 1686 (LOp->getType() != L->getType() || HOp->getType() != H->getType()); 1687 1688 if ((LEE || LSV) && (HEE || HSV) && !IsSizeChangeShuffle) { 1689 // We can have at most two unique vector inputs. 1690 bool CanUseInputs = true; 1691 Value *I1, *I2 = 0; 1692 if (LEE) { 1693 I1 = LEE->getOperand(0); 1694 } else { 1695 I1 = LSV->getOperand(0); 1696 I2 = LSV->getOperand(1); 1697 if (I2 == I1 || isa<UndefValue>(I2)) 1698 I2 = 0; 1699 } 1700 1701 if (HEE) { 1702 Value *I3 = HEE->getOperand(0); 1703 if (!I2 && I3 != I1) 1704 I2 = I3; 1705 else if (I3 != I1 && I3 != I2) 1706 CanUseInputs = false; 1707 } else { 1708 Value *I3 = HSV->getOperand(0); 1709 if (!I2 && I3 != I1) 1710 I2 = I3; 1711 else if (I3 != I1 && I3 != I2) 1712 CanUseInputs = false; 1713 1714 if (CanUseInputs) { 1715 Value *I4 = HSV->getOperand(1); 1716 if (!isa<UndefValue>(I4)) { 1717 if (!I2 && I4 != I1) 1718 I2 = I4; 1719 else if (I4 != I1 && I4 != I2) 1720 CanUseInputs = false; 1721 } 1722 } 1723 } 1724 1725 if (CanUseInputs) { 1726 unsigned LOpElem = 1727 cast<VectorType>(cast<Instruction>(LOp)->getOperand(0)->getType()) 1728 ->getNumElements(); 1729 unsigned HOpElem = 1730 cast<VectorType>(cast<Instruction>(HOp)->getOperand(0)->getType()) 1731 ->getNumElements(); 1732 1733 // We have one or two input vectors. We need to map each index of the 1734 // operands to the index of the original vector. 1735 SmallVector<std::pair<int, int>, 8> II(numElem); 1736 for (unsigned i = 0; i < numElemL; ++i) { 1737 int Idx, INum; 1738 if (LEE) { 1739 Idx = 1740 cast<ConstantInt>(LEE->getOperand(1))->getSExtValue(); 1741 INum = LEE->getOperand(0) == I1 ? 0 : 1; 1742 } else { 1743 Idx = LSV->getMaskValue(i); 1744 if (Idx < (int) LOpElem) { 1745 INum = LSV->getOperand(0) == I1 ? 0 : 1; 1746 } else { 1747 Idx -= LOpElem; 1748 INum = LSV->getOperand(1) == I1 ? 0 : 1; 1749 } 1750 } 1751 1752 II[i] = std::pair<int, int>(Idx, INum); 1753 } 1754 for (unsigned i = 0; i < numElemH; ++i) { 1755 int Idx, INum; 1756 if (HEE) { 1757 Idx = 1758 cast<ConstantInt>(HEE->getOperand(1))->getSExtValue(); 1759 INum = HEE->getOperand(0) == I1 ? 0 : 1; 1760 } else { 1761 Idx = HSV->getMaskValue(i); 1762 if (Idx < (int) HOpElem) { 1763 INum = HSV->getOperand(0) == I1 ? 0 : 1; 1764 } else { 1765 Idx -= HOpElem; 1766 INum = HSV->getOperand(1) == I1 ? 0 : 1; 1767 } 1768 } 1769 1770 II[i + numElemL] = std::pair<int, int>(Idx, INum); 1771 } 1772 1773 // We now have an array which tells us from which index of which 1774 // input vector each element of the operand comes. 1775 VectorType *I1T = cast<VectorType>(I1->getType()); 1776 unsigned I1Elem = I1T->getNumElements(); 1777 1778 if (!I2) { 1779 // In this case there is only one underlying vector input. Check for 1780 // the trivial case where we can use the input directly. 1781 if (I1Elem == numElem) { 1782 bool ElemInOrder = true; 1783 for (unsigned i = 0; i < numElem; ++i) { 1784 if (II[i].first != (int) i && II[i].first != -1) { 1785 ElemInOrder = false; 1786 break; 1787 } 1788 } 1789 1790 if (ElemInOrder) 1791 return I1; 1792 } 1793 1794 // A shuffle is needed. 1795 std::vector<Constant *> Mask(numElem); 1796 for (unsigned i = 0; i < numElem; ++i) { 1797 int Idx = II[i].first; 1798 if (Idx == -1) 1799 Mask[i] = UndefValue::get(Type::getInt32Ty(Context)); 1800 else 1801 Mask[i] = ConstantInt::get(Type::getInt32Ty(Context), Idx); 1802 } 1803 1804 Instruction *S = 1805 new ShuffleVectorInst(I1, UndefValue::get(I1T), 1806 ConstantVector::get(Mask), 1807 getReplacementName(I, true, o)); 1808 S->insertBefore(J); 1809 return S; 1810 } 1811 1812 VectorType *I2T = cast<VectorType>(I2->getType()); 1813 unsigned I2Elem = I2T->getNumElements(); 1814 1815 // This input comes from two distinct vectors. The first step is to 1816 // make sure that both vectors are the same length. If not, the 1817 // smaller one will need to grow before they can be shuffled together. 1818 if (I1Elem < I2Elem) { 1819 std::vector<Constant *> Mask(I2Elem); 1820 unsigned v = 0; 1821 for (; v < I1Elem; ++v) 1822 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v); 1823 for (; v < I2Elem; ++v) 1824 Mask[v] = UndefValue::get(Type::getInt32Ty(Context)); 1825 1826 Instruction *NewI1 = 1827 new ShuffleVectorInst(I1, UndefValue::get(I1T), 1828 ConstantVector::get(Mask), 1829 getReplacementName(I, true, o, 1)); 1830 NewI1->insertBefore(J); 1831 I1 = NewI1; 1832 I1T = I2T; 1833 I1Elem = I2Elem; 1834 } else if (I1Elem > I2Elem) { 1835 std::vector<Constant *> Mask(I1Elem); 1836 unsigned v = 0; 1837 for (; v < I2Elem; ++v) 1838 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v); 1839 for (; v < I1Elem; ++v) 1840 Mask[v] = UndefValue::get(Type::getInt32Ty(Context)); 1841 1842 Instruction *NewI2 = 1843 new ShuffleVectorInst(I2, UndefValue::get(I2T), 1844 ConstantVector::get(Mask), 1845 getReplacementName(I, true, o, 1)); 1846 NewI2->insertBefore(J); 1847 I2 = NewI2; 1848 I2T = I1T; 1849 I2Elem = I1Elem; 1850 } 1851 1852 // Now that both I1 and I2 are the same length we can shuffle them 1853 // together (and use the result). 1854 std::vector<Constant *> Mask(numElem); 1855 for (unsigned v = 0; v < numElem; ++v) { 1856 if (II[v].first == -1) { 1857 Mask[v] = UndefValue::get(Type::getInt32Ty(Context)); 1858 } else { 1859 int Idx = II[v].first + II[v].second * I1Elem; 1860 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), Idx); 1861 } 1862 } 1863 1864 Instruction *NewOp = 1865 new ShuffleVectorInst(I1, I2, ConstantVector::get(Mask), 1866 getReplacementName(I, true, o)); 1867 NewOp->insertBefore(J); 1868 return NewOp; 1869 } 1870 } 1871 1872 Type *ArgType = ArgTypeL; 1873 if (numElemL < numElemH) { 1874 if (numElemL == 1 && expandIEChain(Context, I, J, o, HOp, numElemH, 1875 ArgTypeL, VArgType, 1)) { 1876 // This is another short-circuit case: we're combining a scalar into 1877 // a vector that is formed by an IE chain. We've just expanded the IE 1878 // chain, now insert the scalar and we're done. 1879 1880 Instruction *S = InsertElementInst::Create(HOp, LOp, CV0, 1881 getReplacementName(I, true, o)); 1882 S->insertBefore(J); 1883 return S; 1884 } else if (!expandIEChain(Context, I, J, o, LOp, numElemL, ArgTypeL, 1885 ArgTypeH)) { 1886 // The two vector inputs to the shuffle must be the same length, 1887 // so extend the smaller vector to be the same length as the larger one. 1888 Instruction *NLOp; 1889 if (numElemL > 1) { 1890 1891 std::vector<Constant *> Mask(numElemH); 1892 unsigned v = 0; 1893 for (; v < numElemL; ++v) 1894 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v); 1895 for (; v < numElemH; ++v) 1896 Mask[v] = UndefValue::get(Type::getInt32Ty(Context)); 1897 1898 NLOp = new ShuffleVectorInst(LOp, UndefValue::get(ArgTypeL), 1899 ConstantVector::get(Mask), 1900 getReplacementName(I, true, o, 1)); 1901 } else { 1902 NLOp = InsertElementInst::Create(UndefValue::get(ArgTypeH), LOp, CV0, 1903 getReplacementName(I, true, o, 1)); 1904 } 1905 1906 NLOp->insertBefore(J); 1907 LOp = NLOp; 1908 } 1909 1910 ArgType = ArgTypeH; 1911 } else if (numElemL > numElemH) { 1912 if (numElemH == 1 && expandIEChain(Context, I, J, o, LOp, numElemL, 1913 ArgTypeH, VArgType)) { 1914 Instruction *S = 1915 InsertElementInst::Create(LOp, HOp, 1916 ConstantInt::get(Type::getInt32Ty(Context), 1917 numElemL), 1918 getReplacementName(I, true, o)); 1919 S->insertBefore(J); 1920 return S; 1921 } else if (!expandIEChain(Context, I, J, o, HOp, numElemH, ArgTypeH, 1922 ArgTypeL)) { 1923 Instruction *NHOp; 1924 if (numElemH > 1) { 1925 std::vector<Constant *> Mask(numElemL); 1926 unsigned v = 0; 1927 for (; v < numElemH; ++v) 1928 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v); 1929 for (; v < numElemL; ++v) 1930 Mask[v] = UndefValue::get(Type::getInt32Ty(Context)); 1931 1932 NHOp = new ShuffleVectorInst(HOp, UndefValue::get(ArgTypeH), 1933 ConstantVector::get(Mask), 1934 getReplacementName(I, true, o, 1)); 1935 } else { 1936 NHOp = InsertElementInst::Create(UndefValue::get(ArgTypeL), HOp, CV0, 1937 getReplacementName(I, true, o, 1)); 1938 } 1939 1940 NHOp->insertBefore(J); 1941 HOp = NHOp; 1942 } 1943 } 1944 1945 if (ArgType->isVectorTy()) { 1946 unsigned numElem = cast<VectorType>(VArgType)->getNumElements(); 1947 std::vector<Constant*> Mask(numElem); 1948 for (unsigned v = 0; v < numElem; ++v) { 1949 unsigned Idx = v; 1950 // If the low vector was expanded, we need to skip the extra 1951 // undefined entries. 1952 if (v >= numElemL && numElemH > numElemL) 1953 Idx += (numElemH - numElemL); 1954 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), Idx); 1955 } 1956 1957 Instruction *BV = new ShuffleVectorInst(LOp, HOp, 1958 ConstantVector::get(Mask), 1959 getReplacementName(I, true, o)); 1960 BV->insertBefore(J); 1961 return BV; 1962 } 1963 1964 Instruction *BV1 = InsertElementInst::Create( 1965 UndefValue::get(VArgType), LOp, CV0, 1966 getReplacementName(I, true, o, 1)); 1967 BV1->insertBefore(I); 1968 Instruction *BV2 = InsertElementInst::Create(BV1, HOp, CV1, 1969 getReplacementName(I, true, o, 2)); 1970 BV2->insertBefore(J); 1971 return BV2; 1972 } 1973 1974 // This function creates an array of values that will be used as the inputs 1975 // to the vector instruction that fuses I with J. 1976 void BBVectorize::getReplacementInputsForPair(LLVMContext& Context, 1977 Instruction *I, Instruction *J, 1978 SmallVector<Value *, 3> &ReplacedOperands, 1979 bool FlipMemInputs) { 1980 unsigned NumOperands = I->getNumOperands(); 1981 1982 for (unsigned p = 0, o = NumOperands-1; p < NumOperands; ++p, --o) { 1983 // Iterate backward so that we look at the store pointer 1984 // first and know whether or not we need to flip the inputs. 1985 1986 if (isa<LoadInst>(I) || (o == 1 && isa<StoreInst>(I))) { 1987 // This is the pointer for a load/store instruction. 1988 ReplacedOperands[o] = getReplacementPointerInput(Context, I, J, o, 1989 FlipMemInputs); 1990 continue; 1991 } else if (isa<CallInst>(I)) { 1992 Function *F = cast<CallInst>(I)->getCalledFunction(); 1993 unsigned IID = F->getIntrinsicID(); 1994 if (o == NumOperands-1) { 1995 BasicBlock &BB = *I->getParent(); 1996 1997 Module *M = BB.getParent()->getParent(); 1998 Type *ArgTypeI = I->getType(); 1999 Type *ArgTypeJ = J->getType(); 2000 Type *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ); 2001 2002 ReplacedOperands[o] = Intrinsic::getDeclaration(M, 2003 (Intrinsic::ID) IID, VArgType); 2004 continue; 2005 } else if (IID == Intrinsic::powi && o == 1) { 2006 // The second argument of powi is a single integer and we've already 2007 // checked that both arguments are equal. As a result, we just keep 2008 // I's second argument. 2009 ReplacedOperands[o] = I->getOperand(o); 2010 continue; 2011 } 2012 } else if (isa<ShuffleVectorInst>(I) && o == NumOperands-1) { 2013 ReplacedOperands[o] = getReplacementShuffleMask(Context, I, J); 2014 continue; 2015 } 2016 2017 ReplacedOperands[o] = 2018 getReplacementInput(Context, I, J, o, FlipMemInputs); 2019 } 2020 } 2021 2022 // This function creates two values that represent the outputs of the 2023 // original I and J instructions. These are generally vector shuffles 2024 // or extracts. In many cases, these will end up being unused and, thus, 2025 // eliminated by later passes. 2026 void BBVectorize::replaceOutputsOfPair(LLVMContext& Context, Instruction *I, 2027 Instruction *J, Instruction *K, 2028 Instruction *&InsertionPt, 2029 Instruction *&K1, Instruction *&K2, 2030 bool FlipMemInputs) { 2031 if (isa<StoreInst>(I)) { 2032 AA->replaceWithNewValue(I, K); 2033 AA->replaceWithNewValue(J, K); 2034 } else { 2035 Type *IType = I->getType(); 2036 Type *JType = J->getType(); 2037 2038 VectorType *VType = getVecTypeForPair(IType, JType); 2039 unsigned numElem = VType->getNumElements(); 2040 2041 unsigned numElemI, numElemJ; 2042 if (IType->isVectorTy()) 2043 numElemI = cast<VectorType>(IType)->getNumElements(); 2044 else 2045 numElemI = 1; 2046 2047 if (JType->isVectorTy()) 2048 numElemJ = cast<VectorType>(JType)->getNumElements(); 2049 else 2050 numElemJ = 1; 2051 2052 if (IType->isVectorTy()) { 2053 std::vector<Constant*> Mask1(numElemI), Mask2(numElemI); 2054 for (unsigned v = 0; v < numElemI; ++v) { 2055 Mask1[v] = ConstantInt::get(Type::getInt32Ty(Context), v); 2056 Mask2[v] = ConstantInt::get(Type::getInt32Ty(Context), numElemJ+v); 2057 } 2058 2059 K1 = new ShuffleVectorInst(K, UndefValue::get(VType), 2060 ConstantVector::get( 2061 FlipMemInputs ? Mask2 : Mask1), 2062 getReplacementName(K, false, 1)); 2063 } else { 2064 Value *CV0 = ConstantInt::get(Type::getInt32Ty(Context), 0); 2065 Value *CV1 = ConstantInt::get(Type::getInt32Ty(Context), numElem-1); 2066 K1 = ExtractElementInst::Create(K, FlipMemInputs ? CV1 : CV0, 2067 getReplacementName(K, false, 1)); 2068 } 2069 2070 if (JType->isVectorTy()) { 2071 std::vector<Constant*> Mask1(numElemJ), Mask2(numElemJ); 2072 for (unsigned v = 0; v < numElemJ; ++v) { 2073 Mask1[v] = ConstantInt::get(Type::getInt32Ty(Context), v); 2074 Mask2[v] = ConstantInt::get(Type::getInt32Ty(Context), numElemI+v); 2075 } 2076 2077 K2 = new ShuffleVectorInst(K, UndefValue::get(VType), 2078 ConstantVector::get( 2079 FlipMemInputs ? Mask1 : Mask2), 2080 getReplacementName(K, false, 2)); 2081 } else { 2082 Value *CV0 = ConstantInt::get(Type::getInt32Ty(Context), 0); 2083 Value *CV1 = ConstantInt::get(Type::getInt32Ty(Context), numElem-1); 2084 K2 = ExtractElementInst::Create(K, FlipMemInputs ? CV0 : CV1, 2085 getReplacementName(K, false, 2)); 2086 } 2087 2088 K1->insertAfter(K); 2089 K2->insertAfter(K1); 2090 InsertionPt = K2; 2091 } 2092 } 2093 2094 // Move all uses of the function I (including pairing-induced uses) after J. 2095 bool BBVectorize::canMoveUsesOfIAfterJ(BasicBlock &BB, 2096 std::multimap<Value *, Value *> &LoadMoveSet, 2097 Instruction *I, Instruction *J) { 2098 // Skip to the first instruction past I. 2099 BasicBlock::iterator L = llvm::next(BasicBlock::iterator(I)); 2100 2101 DenseSet<Value *> Users; 2102 AliasSetTracker WriteSet(*AA); 2103 for (; cast<Instruction>(L) != J; ++L) 2104 (void) trackUsesOfI(Users, WriteSet, I, L, true, &LoadMoveSet); 2105 2106 assert(cast<Instruction>(L) == J && 2107 "Tracking has not proceeded far enough to check for dependencies"); 2108 // If J is now in the use set of I, then trackUsesOfI will return true 2109 // and we have a dependency cycle (and the fusing operation must abort). 2110 return !trackUsesOfI(Users, WriteSet, I, J, true, &LoadMoveSet); 2111 } 2112 2113 // Move all uses of the function I (including pairing-induced uses) after J. 2114 void BBVectorize::moveUsesOfIAfterJ(BasicBlock &BB, 2115 std::multimap<Value *, Value *> &LoadMoveSet, 2116 Instruction *&InsertionPt, 2117 Instruction *I, Instruction *J) { 2118 // Skip to the first instruction past I. 2119 BasicBlock::iterator L = llvm::next(BasicBlock::iterator(I)); 2120 2121 DenseSet<Value *> Users; 2122 AliasSetTracker WriteSet(*AA); 2123 for (; cast<Instruction>(L) != J;) { 2124 if (trackUsesOfI(Users, WriteSet, I, L, true, &LoadMoveSet)) { 2125 // Move this instruction 2126 Instruction *InstToMove = L; ++L; 2127 2128 DEBUG(dbgs() << "BBV: moving: " << *InstToMove << 2129 " to after " << *InsertionPt << "\n"); 2130 InstToMove->removeFromParent(); 2131 InstToMove->insertAfter(InsertionPt); 2132 InsertionPt = InstToMove; 2133 } else { 2134 ++L; 2135 } 2136 } 2137 } 2138 2139 // Collect all load instruction that are in the move set of a given first 2140 // pair member. These loads depend on the first instruction, I, and so need 2141 // to be moved after J (the second instruction) when the pair is fused. 2142 void BBVectorize::collectPairLoadMoveSet(BasicBlock &BB, 2143 DenseMap<Value *, Value *> &ChosenPairs, 2144 std::multimap<Value *, Value *> &LoadMoveSet, 2145 Instruction *I) { 2146 // Skip to the first instruction past I. 2147 BasicBlock::iterator L = llvm::next(BasicBlock::iterator(I)); 2148 2149 DenseSet<Value *> Users; 2150 AliasSetTracker WriteSet(*AA); 2151 2152 // Note: We cannot end the loop when we reach J because J could be moved 2153 // farther down the use chain by another instruction pairing. Also, J 2154 // could be before I if this is an inverted input. 2155 for (BasicBlock::iterator E = BB.end(); cast<Instruction>(L) != E; ++L) { 2156 if (trackUsesOfI(Users, WriteSet, I, L)) { 2157 if (L->mayReadFromMemory()) 2158 LoadMoveSet.insert(ValuePair(L, I)); 2159 } 2160 } 2161 } 2162 2163 // In cases where both load/stores and the computation of their pointers 2164 // are chosen for vectorization, we can end up in a situation where the 2165 // aliasing analysis starts returning different query results as the 2166 // process of fusing instruction pairs continues. Because the algorithm 2167 // relies on finding the same use trees here as were found earlier, we'll 2168 // need to precompute the necessary aliasing information here and then 2169 // manually update it during the fusion process. 2170 void BBVectorize::collectLoadMoveSet(BasicBlock &BB, 2171 std::vector<Value *> &PairableInsts, 2172 DenseMap<Value *, Value *> &ChosenPairs, 2173 std::multimap<Value *, Value *> &LoadMoveSet) { 2174 for (std::vector<Value *>::iterator PI = PairableInsts.begin(), 2175 PIE = PairableInsts.end(); PI != PIE; ++PI) { 2176 DenseMap<Value *, Value *>::iterator P = ChosenPairs.find(*PI); 2177 if (P == ChosenPairs.end()) continue; 2178 2179 Instruction *I = cast<Instruction>(P->first); 2180 collectPairLoadMoveSet(BB, ChosenPairs, LoadMoveSet, I); 2181 } 2182 } 2183 2184 // As with the aliasing information, SCEV can also change because of 2185 // vectorization. This information is used to compute relative pointer 2186 // offsets; the necessary information will be cached here prior to 2187 // fusion. 2188 void BBVectorize::collectPtrInfo(std::vector<Value *> &PairableInsts, 2189 DenseMap<Value *, Value *> &ChosenPairs, 2190 DenseSet<Value *> &LowPtrInsts) { 2191 for (std::vector<Value *>::iterator PI = PairableInsts.begin(), 2192 PIE = PairableInsts.end(); PI != PIE; ++PI) { 2193 DenseMap<Value *, Value *>::iterator P = ChosenPairs.find(*PI); 2194 if (P == ChosenPairs.end()) continue; 2195 2196 Instruction *I = cast<Instruction>(P->first); 2197 Instruction *J = cast<Instruction>(P->second); 2198 2199 if (!isa<LoadInst>(I) && !isa<StoreInst>(I)) 2200 continue; 2201 2202 Value *IPtr, *JPtr; 2203 unsigned IAlignment, JAlignment; 2204 int64_t OffsetInElmts; 2205 if (!getPairPtrInfo(I, J, IPtr, JPtr, IAlignment, JAlignment, 2206 OffsetInElmts) || abs64(OffsetInElmts) != 1) 2207 llvm_unreachable("Pre-fusion pointer analysis failed"); 2208 2209 Value *LowPI = (OffsetInElmts > 0) ? I : J; 2210 LowPtrInsts.insert(LowPI); 2211 } 2212 } 2213 2214 // When the first instruction in each pair is cloned, it will inherit its 2215 // parent's metadata. This metadata must be combined with that of the other 2216 // instruction in a safe way. 2217 void BBVectorize::combineMetadata(Instruction *K, const Instruction *J) { 2218 SmallVector<std::pair<unsigned, MDNode*>, 4> Metadata; 2219 K->getAllMetadataOtherThanDebugLoc(Metadata); 2220 for (unsigned i = 0, n = Metadata.size(); i < n; ++i) { 2221 unsigned Kind = Metadata[i].first; 2222 MDNode *JMD = J->getMetadata(Kind); 2223 MDNode *KMD = Metadata[i].second; 2224 2225 switch (Kind) { 2226 default: 2227 K->setMetadata(Kind, 0); // Remove unknown metadata 2228 break; 2229 case LLVMContext::MD_tbaa: 2230 K->setMetadata(Kind, MDNode::getMostGenericTBAA(JMD, KMD)); 2231 break; 2232 case LLVMContext::MD_fpmath: 2233 K->setMetadata(Kind, MDNode::getMostGenericFPMath(JMD, KMD)); 2234 break; 2235 } 2236 } 2237 } 2238 2239 // This function fuses the chosen instruction pairs into vector instructions, 2240 // taking care preserve any needed scalar outputs and, then, it reorders the 2241 // remaining instructions as needed (users of the first member of the pair 2242 // need to be moved to after the location of the second member of the pair 2243 // because the vector instruction is inserted in the location of the pair's 2244 // second member). 2245 void BBVectorize::fuseChosenPairs(BasicBlock &BB, 2246 std::vector<Value *> &PairableInsts, 2247 DenseMap<Value *, Value *> &ChosenPairs) { 2248 LLVMContext& Context = BB.getContext(); 2249 2250 // During the vectorization process, the order of the pairs to be fused 2251 // could be flipped. So we'll add each pair, flipped, into the ChosenPairs 2252 // list. After a pair is fused, the flipped pair is removed from the list. 2253 std::vector<ValuePair> FlippedPairs; 2254 FlippedPairs.reserve(ChosenPairs.size()); 2255 for (DenseMap<Value *, Value *>::iterator P = ChosenPairs.begin(), 2256 E = ChosenPairs.end(); P != E; ++P) 2257 FlippedPairs.push_back(ValuePair(P->second, P->first)); 2258 for (std::vector<ValuePair>::iterator P = FlippedPairs.begin(), 2259 E = FlippedPairs.end(); P != E; ++P) 2260 ChosenPairs.insert(*P); 2261 2262 std::multimap<Value *, Value *> LoadMoveSet; 2263 collectLoadMoveSet(BB, PairableInsts, ChosenPairs, LoadMoveSet); 2264 2265 DenseSet<Value *> LowPtrInsts; 2266 collectPtrInfo(PairableInsts, ChosenPairs, LowPtrInsts); 2267 2268 DEBUG(dbgs() << "BBV: initial: \n" << BB << "\n"); 2269 2270 for (BasicBlock::iterator PI = BB.getFirstInsertionPt(); PI != BB.end();) { 2271 DenseMap<Value *, Value *>::iterator P = ChosenPairs.find(PI); 2272 if (P == ChosenPairs.end()) { 2273 ++PI; 2274 continue; 2275 } 2276 2277 if (getDepthFactor(P->first) == 0) { 2278 // These instructions are not really fused, but are tracked as though 2279 // they are. Any case in which it would be interesting to fuse them 2280 // will be taken care of by InstCombine. 2281 --NumFusedOps; 2282 ++PI; 2283 continue; 2284 } 2285 2286 Instruction *I = cast<Instruction>(P->first), 2287 *J = cast<Instruction>(P->second); 2288 2289 DEBUG(dbgs() << "BBV: fusing: " << *I << 2290 " <-> " << *J << "\n"); 2291 2292 // Remove the pair and flipped pair from the list. 2293 DenseMap<Value *, Value *>::iterator FP = ChosenPairs.find(P->second); 2294 assert(FP != ChosenPairs.end() && "Flipped pair not found in list"); 2295 ChosenPairs.erase(FP); 2296 ChosenPairs.erase(P); 2297 2298 if (!canMoveUsesOfIAfterJ(BB, LoadMoveSet, I, J)) { 2299 DEBUG(dbgs() << "BBV: fusion of: " << *I << 2300 " <-> " << *J << 2301 " aborted because of non-trivial dependency cycle\n"); 2302 --NumFusedOps; 2303 ++PI; 2304 continue; 2305 } 2306 2307 bool FlipMemInputs = false; 2308 if (isa<LoadInst>(I) || isa<StoreInst>(I)) 2309 FlipMemInputs = (LowPtrInsts.find(I) == LowPtrInsts.end()); 2310 2311 unsigned NumOperands = I->getNumOperands(); 2312 SmallVector<Value *, 3> ReplacedOperands(NumOperands); 2313 getReplacementInputsForPair(Context, I, J, ReplacedOperands, 2314 FlipMemInputs); 2315 2316 // Make a copy of the original operation, change its type to the vector 2317 // type and replace its operands with the vector operands. 2318 Instruction *K = I->clone(); 2319 if (I->hasName()) K->takeName(I); 2320 2321 if (!isa<StoreInst>(K)) 2322 K->mutateType(getVecTypeForPair(I->getType(), J->getType())); 2323 2324 combineMetadata(K, J); 2325 2326 for (unsigned o = 0; o < NumOperands; ++o) 2327 K->setOperand(o, ReplacedOperands[o]); 2328 2329 // If we've flipped the memory inputs, make sure that we take the correct 2330 // alignment. 2331 if (FlipMemInputs) { 2332 if (isa<StoreInst>(K)) 2333 cast<StoreInst>(K)->setAlignment(cast<StoreInst>(J)->getAlignment()); 2334 else 2335 cast<LoadInst>(K)->setAlignment(cast<LoadInst>(J)->getAlignment()); 2336 } 2337 2338 K->insertAfter(J); 2339 2340 // Instruction insertion point: 2341 Instruction *InsertionPt = K; 2342 Instruction *K1 = 0, *K2 = 0; 2343 replaceOutputsOfPair(Context, I, J, K, InsertionPt, K1, K2, 2344 FlipMemInputs); 2345 2346 // The use tree of the first original instruction must be moved to after 2347 // the location of the second instruction. The entire use tree of the 2348 // first instruction is disjoint from the input tree of the second 2349 // (by definition), and so commutes with it. 2350 2351 moveUsesOfIAfterJ(BB, LoadMoveSet, InsertionPt, I, J); 2352 2353 if (!isa<StoreInst>(I)) { 2354 I->replaceAllUsesWith(K1); 2355 J->replaceAllUsesWith(K2); 2356 AA->replaceWithNewValue(I, K1); 2357 AA->replaceWithNewValue(J, K2); 2358 } 2359 2360 // Instructions that may read from memory may be in the load move set. 2361 // Once an instruction is fused, we no longer need its move set, and so 2362 // the values of the map never need to be updated. However, when a load 2363 // is fused, we need to merge the entries from both instructions in the 2364 // pair in case those instructions were in the move set of some other 2365 // yet-to-be-fused pair. The loads in question are the keys of the map. 2366 if (I->mayReadFromMemory()) { 2367 std::vector<ValuePair> NewSetMembers; 2368 VPIteratorPair IPairRange = LoadMoveSet.equal_range(I); 2369 VPIteratorPair JPairRange = LoadMoveSet.equal_range(J); 2370 for (std::multimap<Value *, Value *>::iterator N = IPairRange.first; 2371 N != IPairRange.second; ++N) 2372 NewSetMembers.push_back(ValuePair(K, N->second)); 2373 for (std::multimap<Value *, Value *>::iterator N = JPairRange.first; 2374 N != JPairRange.second; ++N) 2375 NewSetMembers.push_back(ValuePair(K, N->second)); 2376 for (std::vector<ValuePair>::iterator A = NewSetMembers.begin(), 2377 AE = NewSetMembers.end(); A != AE; ++A) 2378 LoadMoveSet.insert(*A); 2379 } 2380 2381 // Before removing I, set the iterator to the next instruction. 2382 PI = llvm::next(BasicBlock::iterator(I)); 2383 if (cast<Instruction>(PI) == J) 2384 ++PI; 2385 2386 SE->forgetValue(I); 2387 SE->forgetValue(J); 2388 I->eraseFromParent(); 2389 J->eraseFromParent(); 2390 } 2391 2392 DEBUG(dbgs() << "BBV: final: \n" << BB << "\n"); 2393 } 2394} 2395 2396char BBVectorize::ID = 0; 2397static const char bb_vectorize_name[] = "Basic-Block Vectorization"; 2398INITIALIZE_PASS_BEGIN(BBVectorize, BBV_NAME, bb_vectorize_name, false, false) 2399INITIALIZE_AG_DEPENDENCY(AliasAnalysis) 2400INITIALIZE_PASS_DEPENDENCY(ScalarEvolution) 2401INITIALIZE_PASS_END(BBVectorize, BBV_NAME, bb_vectorize_name, false, false) 2402 2403BasicBlockPass *llvm::createBBVectorizePass(const VectorizeConfig &C) { 2404 return new BBVectorize(C); 2405} 2406 2407bool 2408llvm::vectorizeBasicBlock(Pass *P, BasicBlock &BB, const VectorizeConfig &C) { 2409 BBVectorize BBVectorizer(P, C); 2410 return BBVectorizer.vectorizeBB(BB); 2411} 2412 2413//===----------------------------------------------------------------------===// 2414VectorizeConfig::VectorizeConfig() { 2415 VectorBits = ::VectorBits; 2416 VectorizeBools = !::NoBools; 2417 VectorizeInts = !::NoInts; 2418 VectorizeFloats = !::NoFloats; 2419 VectorizePointers = !::NoPointers; 2420 VectorizeCasts = !::NoCasts; 2421 VectorizeMath = !::NoMath; 2422 VectorizeFMA = !::NoFMA; 2423 VectorizeSelect = !::NoSelect; 2424 VectorizeCmp = !::NoCmp; 2425 VectorizeGEP = !::NoGEP; 2426 VectorizeMemOps = !::NoMemOps; 2427 AlignedOnly = ::AlignedOnly; 2428 ReqChainDepth= ::ReqChainDepth; 2429 SearchLimit = ::SearchLimit; 2430 MaxCandPairsForCycleCheck = ::MaxCandPairsForCycleCheck; 2431 SplatBreaksChain = ::SplatBreaksChain; 2432 MaxInsts = ::MaxInsts; 2433 MaxIter = ::MaxIter; 2434 Pow2LenOnly = ::Pow2LenOnly; 2435 NoMemOpBoost = ::NoMemOpBoost; 2436 FastDep = ::FastDep; 2437} 2438