BBVectorize.cpp revision 78fd353d5e5daedc47ecc31b6193ca48793c249c
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/Dominators.h" 38#include "llvm/Analysis/ScalarEvolution.h" 39#include "llvm/Analysis/ScalarEvolutionExpressions.h" 40#include "llvm/Analysis/ValueTracking.h" 41#include "llvm/Support/CommandLine.h" 42#include "llvm/Support/Debug.h" 43#include "llvm/Support/raw_ostream.h" 44#include "llvm/Support/ValueHandle.h" 45#include "llvm/DataLayout.h" 46#include "llvm/TargetTransformInfo.h" 47#include "llvm/Transforms/Utils/Local.h" 48#include "llvm/Transforms/Vectorize.h" 49#include <algorithm> 50#include <map> 51using namespace llvm; 52 53static cl::opt<bool> 54IgnoreTargetInfo("bb-vectorize-ignore-target-info", cl::init(false), 55 cl::Hidden, cl::desc("Ignore target information")); 56 57static cl::opt<unsigned> 58ReqChainDepth("bb-vectorize-req-chain-depth", cl::init(6), cl::Hidden, 59 cl::desc("The required chain depth for vectorization")); 60 61static cl::opt<bool> 62UseChainDepthWithTI("bb-vectorize-use-chain-depth", cl::init(false), 63 cl::Hidden, cl::desc("Use the chain depth requirement with" 64 " target information")); 65 66static cl::opt<unsigned> 67SearchLimit("bb-vectorize-search-limit", cl::init(400), cl::Hidden, 68 cl::desc("The maximum search distance for instruction pairs")); 69 70static cl::opt<bool> 71SplatBreaksChain("bb-vectorize-splat-breaks-chain", cl::init(false), cl::Hidden, 72 cl::desc("Replicating one element to a pair breaks the chain")); 73 74static cl::opt<unsigned> 75VectorBits("bb-vectorize-vector-bits", cl::init(128), cl::Hidden, 76 cl::desc("The size of the native vector registers")); 77 78static cl::opt<unsigned> 79MaxIter("bb-vectorize-max-iter", cl::init(0), cl::Hidden, 80 cl::desc("The maximum number of pairing iterations")); 81 82static cl::opt<bool> 83Pow2LenOnly("bb-vectorize-pow2-len-only", cl::init(false), cl::Hidden, 84 cl::desc("Don't try to form non-2^n-length vectors")); 85 86static cl::opt<unsigned> 87MaxInsts("bb-vectorize-max-instr-per-group", cl::init(500), cl::Hidden, 88 cl::desc("The maximum number of pairable instructions per group")); 89 90static cl::opt<unsigned> 91MaxCandPairsForCycleCheck("bb-vectorize-max-cycle-check-pairs", cl::init(200), 92 cl::Hidden, cl::desc("The maximum number of candidate pairs with which to use" 93 " a full cycle check")); 94 95static cl::opt<bool> 96NoBools("bb-vectorize-no-bools", cl::init(false), cl::Hidden, 97 cl::desc("Don't try to vectorize boolean (i1) values")); 98 99static cl::opt<bool> 100NoInts("bb-vectorize-no-ints", cl::init(false), cl::Hidden, 101 cl::desc("Don't try to vectorize integer values")); 102 103static cl::opt<bool> 104NoFloats("bb-vectorize-no-floats", cl::init(false), cl::Hidden, 105 cl::desc("Don't try to vectorize floating-point values")); 106 107// FIXME: This should default to false once pointer vector support works. 108static cl::opt<bool> 109NoPointers("bb-vectorize-no-pointers", cl::init(/*false*/ true), cl::Hidden, 110 cl::desc("Don't try to vectorize pointer values")); 111 112static cl::opt<bool> 113NoCasts("bb-vectorize-no-casts", cl::init(false), cl::Hidden, 114 cl::desc("Don't try to vectorize casting (conversion) operations")); 115 116static cl::opt<bool> 117NoMath("bb-vectorize-no-math", cl::init(false), cl::Hidden, 118 cl::desc("Don't try to vectorize floating-point math intrinsics")); 119 120static cl::opt<bool> 121NoFMA("bb-vectorize-no-fma", cl::init(false), cl::Hidden, 122 cl::desc("Don't try to vectorize the fused-multiply-add intrinsic")); 123 124static cl::opt<bool> 125NoSelect("bb-vectorize-no-select", cl::init(false), cl::Hidden, 126 cl::desc("Don't try to vectorize select instructions")); 127 128static cl::opt<bool> 129NoCmp("bb-vectorize-no-cmp", cl::init(false), cl::Hidden, 130 cl::desc("Don't try to vectorize comparison instructions")); 131 132static cl::opt<bool> 133NoGEP("bb-vectorize-no-gep", cl::init(false), cl::Hidden, 134 cl::desc("Don't try to vectorize getelementptr instructions")); 135 136static cl::opt<bool> 137NoMemOps("bb-vectorize-no-mem-ops", cl::init(false), cl::Hidden, 138 cl::desc("Don't try to vectorize loads and stores")); 139 140static cl::opt<bool> 141AlignedOnly("bb-vectorize-aligned-only", cl::init(false), cl::Hidden, 142 cl::desc("Only generate aligned loads and stores")); 143 144static cl::opt<bool> 145NoMemOpBoost("bb-vectorize-no-mem-op-boost", 146 cl::init(false), cl::Hidden, 147 cl::desc("Don't boost the chain-depth contribution of loads and stores")); 148 149static cl::opt<bool> 150FastDep("bb-vectorize-fast-dep", cl::init(false), cl::Hidden, 151 cl::desc("Use a fast instruction dependency analysis")); 152 153#ifndef NDEBUG 154static cl::opt<bool> 155DebugInstructionExamination("bb-vectorize-debug-instruction-examination", 156 cl::init(false), cl::Hidden, 157 cl::desc("When debugging is enabled, output information on the" 158 " instruction-examination process")); 159static cl::opt<bool> 160DebugCandidateSelection("bb-vectorize-debug-candidate-selection", 161 cl::init(false), cl::Hidden, 162 cl::desc("When debugging is enabled, output information on the" 163 " candidate-selection process")); 164static cl::opt<bool> 165DebugPairSelection("bb-vectorize-debug-pair-selection", 166 cl::init(false), cl::Hidden, 167 cl::desc("When debugging is enabled, output information on the" 168 " pair-selection process")); 169static cl::opt<bool> 170DebugCycleCheck("bb-vectorize-debug-cycle-check", 171 cl::init(false), cl::Hidden, 172 cl::desc("When debugging is enabled, output information on the" 173 " cycle-checking process")); 174 175static cl::opt<bool> 176PrintAfterEveryPair("bb-vectorize-debug-print-after-every-pair", 177 cl::init(false), cl::Hidden, 178 cl::desc("When debugging is enabled, dump the basic block after" 179 " every pair is fused")); 180#endif 181 182STATISTIC(NumFusedOps, "Number of operations fused by bb-vectorize"); 183 184namespace { 185 struct BBVectorize : public BasicBlockPass { 186 static char ID; // Pass identification, replacement for typeid 187 188 const VectorizeConfig Config; 189 190 BBVectorize(const VectorizeConfig &C = VectorizeConfig()) 191 : BasicBlockPass(ID), Config(C) { 192 initializeBBVectorizePass(*PassRegistry::getPassRegistry()); 193 } 194 195 BBVectorize(Pass *P, const VectorizeConfig &C) 196 : BasicBlockPass(ID), Config(C) { 197 AA = &P->getAnalysis<AliasAnalysis>(); 198 DT = &P->getAnalysis<DominatorTree>(); 199 SE = &P->getAnalysis<ScalarEvolution>(); 200 TD = P->getAnalysisIfAvailable<DataLayout>(); 201 TTI = IgnoreTargetInfo ? 0 : 202 P->getAnalysisIfAvailable<TargetTransformInfo>(); 203 VTTI = TTI ? TTI->getVectorTargetTransformInfo() : 0; 204 } 205 206 typedef std::pair<Value *, Value *> ValuePair; 207 typedef std::pair<ValuePair, int> ValuePairWithCost; 208 typedef std::pair<ValuePair, size_t> ValuePairWithDepth; 209 typedef std::pair<ValuePair, ValuePair> VPPair; // A ValuePair pair 210 typedef std::pair<VPPair, unsigned> VPPairWithType; 211 typedef std::pair<std::multimap<Value *, Value *>::iterator, 212 std::multimap<Value *, Value *>::iterator> VPIteratorPair; 213 typedef std::pair<std::multimap<ValuePair, ValuePair>::iterator, 214 std::multimap<ValuePair, ValuePair>::iterator> 215 VPPIteratorPair; 216 217 AliasAnalysis *AA; 218 DominatorTree *DT; 219 ScalarEvolution *SE; 220 DataLayout *TD; 221 TargetTransformInfo *TTI; 222 const VectorTargetTransformInfo *VTTI; 223 224 // FIXME: const correct? 225 226 bool vectorizePairs(BasicBlock &BB, bool NonPow2Len = false); 227 228 bool getCandidatePairs(BasicBlock &BB, 229 BasicBlock::iterator &Start, 230 std::multimap<Value *, Value *> &CandidatePairs, 231 DenseSet<ValuePair> &FixedOrderPairs, 232 DenseMap<ValuePair, int> &CandidatePairCostSavings, 233 std::vector<Value *> &PairableInsts, bool NonPow2Len); 234 235 // FIXME: The current implementation does not account for pairs that 236 // are connected in multiple ways. For example: 237 // C1 = A1 / A2; C2 = A2 / A1 (which may be both direct and a swap) 238 enum PairConnectionType { 239 PairConnectionDirect, 240 PairConnectionSwap, 241 PairConnectionSplat 242 }; 243 244 void computeConnectedPairs(std::multimap<Value *, Value *> &CandidatePairs, 245 std::vector<Value *> &PairableInsts, 246 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 247 DenseMap<VPPair, unsigned> &PairConnectionTypes); 248 249 void buildDepMap(BasicBlock &BB, 250 std::multimap<Value *, Value *> &CandidatePairs, 251 std::vector<Value *> &PairableInsts, 252 DenseSet<ValuePair> &PairableInstUsers); 253 254 void choosePairs(std::multimap<Value *, Value *> &CandidatePairs, 255 DenseMap<ValuePair, int> &CandidatePairCostSavings, 256 std::vector<Value *> &PairableInsts, 257 DenseSet<ValuePair> &FixedOrderPairs, 258 DenseMap<VPPair, unsigned> &PairConnectionTypes, 259 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 260 std::multimap<ValuePair, ValuePair> &ConnectedPairDeps, 261 DenseSet<ValuePair> &PairableInstUsers, 262 DenseMap<Value *, Value *>& ChosenPairs); 263 264 void fuseChosenPairs(BasicBlock &BB, 265 std::vector<Value *> &PairableInsts, 266 DenseMap<Value *, Value *>& ChosenPairs, 267 DenseSet<ValuePair> &FixedOrderPairs, 268 DenseMap<VPPair, unsigned> &PairConnectionTypes, 269 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 270 std::multimap<ValuePair, ValuePair> &ConnectedPairDeps); 271 272 273 bool isInstVectorizable(Instruction *I, bool &IsSimpleLoadStore); 274 275 bool areInstsCompatible(Instruction *I, Instruction *J, 276 bool IsSimpleLoadStore, bool NonPow2Len, 277 int &CostSavings, int &FixedOrder); 278 279 bool trackUsesOfI(DenseSet<Value *> &Users, 280 AliasSetTracker &WriteSet, Instruction *I, 281 Instruction *J, bool UpdateUsers = true, 282 std::multimap<Value *, Value *> *LoadMoveSet = 0); 283 284 void computePairsConnectedTo( 285 std::multimap<Value *, Value *> &CandidatePairs, 286 std::vector<Value *> &PairableInsts, 287 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 288 DenseMap<VPPair, unsigned> &PairConnectionTypes, 289 ValuePair P); 290 291 bool pairsConflict(ValuePair P, ValuePair Q, 292 DenseSet<ValuePair> &PairableInstUsers, 293 std::multimap<ValuePair, ValuePair> *PairableInstUserMap = 0); 294 295 bool pairWillFormCycle(ValuePair P, 296 std::multimap<ValuePair, ValuePair> &PairableInstUsers, 297 DenseSet<ValuePair> &CurrentPairs); 298 299 void pruneTreeFor( 300 std::multimap<Value *, Value *> &CandidatePairs, 301 std::vector<Value *> &PairableInsts, 302 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 303 DenseSet<ValuePair> &PairableInstUsers, 304 std::multimap<ValuePair, ValuePair> &PairableInstUserMap, 305 DenseMap<Value *, Value *> &ChosenPairs, 306 DenseMap<ValuePair, size_t> &Tree, 307 DenseSet<ValuePair> &PrunedTree, ValuePair J, 308 bool UseCycleCheck); 309 310 void buildInitialTreeFor( 311 std::multimap<Value *, Value *> &CandidatePairs, 312 std::vector<Value *> &PairableInsts, 313 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 314 DenseSet<ValuePair> &PairableInstUsers, 315 DenseMap<Value *, Value *> &ChosenPairs, 316 DenseMap<ValuePair, size_t> &Tree, ValuePair J); 317 318 void findBestTreeFor( 319 std::multimap<Value *, Value *> &CandidatePairs, 320 DenseMap<ValuePair, int> &CandidatePairCostSavings, 321 std::vector<Value *> &PairableInsts, 322 DenseSet<ValuePair> &FixedOrderPairs, 323 DenseMap<VPPair, unsigned> &PairConnectionTypes, 324 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 325 std::multimap<ValuePair, ValuePair> &ConnectedPairDeps, 326 DenseSet<ValuePair> &PairableInstUsers, 327 std::multimap<ValuePair, ValuePair> &PairableInstUserMap, 328 DenseMap<Value *, Value *> &ChosenPairs, 329 DenseSet<ValuePair> &BestTree, size_t &BestMaxDepth, 330 int &BestEffSize, VPIteratorPair ChoiceRange, 331 bool UseCycleCheck); 332 333 Value *getReplacementPointerInput(LLVMContext& Context, Instruction *I, 334 Instruction *J, unsigned o); 335 336 void fillNewShuffleMask(LLVMContext& Context, Instruction *J, 337 unsigned MaskOffset, unsigned NumInElem, 338 unsigned NumInElem1, unsigned IdxOffset, 339 std::vector<Constant*> &Mask); 340 341 Value *getReplacementShuffleMask(LLVMContext& Context, Instruction *I, 342 Instruction *J); 343 344 bool expandIEChain(LLVMContext& Context, Instruction *I, Instruction *J, 345 unsigned o, Value *&LOp, unsigned numElemL, 346 Type *ArgTypeL, Type *ArgTypeR, bool IBeforeJ, 347 unsigned IdxOff = 0); 348 349 Value *getReplacementInput(LLVMContext& Context, Instruction *I, 350 Instruction *J, unsigned o, bool IBeforeJ); 351 352 void getReplacementInputsForPair(LLVMContext& Context, Instruction *I, 353 Instruction *J, SmallVector<Value *, 3> &ReplacedOperands, 354 bool IBeforeJ); 355 356 void replaceOutputsOfPair(LLVMContext& Context, Instruction *I, 357 Instruction *J, Instruction *K, 358 Instruction *&InsertionPt, Instruction *&K1, 359 Instruction *&K2); 360 361 void collectPairLoadMoveSet(BasicBlock &BB, 362 DenseMap<Value *, Value *> &ChosenPairs, 363 std::multimap<Value *, Value *> &LoadMoveSet, 364 Instruction *I); 365 366 void collectLoadMoveSet(BasicBlock &BB, 367 std::vector<Value *> &PairableInsts, 368 DenseMap<Value *, Value *> &ChosenPairs, 369 std::multimap<Value *, Value *> &LoadMoveSet); 370 371 bool canMoveUsesOfIAfterJ(BasicBlock &BB, 372 std::multimap<Value *, Value *> &LoadMoveSet, 373 Instruction *I, Instruction *J); 374 375 void moveUsesOfIAfterJ(BasicBlock &BB, 376 std::multimap<Value *, Value *> &LoadMoveSet, 377 Instruction *&InsertionPt, 378 Instruction *I, Instruction *J); 379 380 void combineMetadata(Instruction *K, const Instruction *J); 381 382 bool vectorizeBB(BasicBlock &BB) { 383 if (!DT->isReachableFromEntry(&BB)) { 384 DEBUG(dbgs() << "BBV: skipping unreachable " << BB.getName() << 385 " in " << BB.getParent()->getName() << "\n"); 386 return false; 387 } 388 389 DEBUG(if (VTTI) dbgs() << "BBV: using target information\n"); 390 391 bool changed = false; 392 // Iterate a sufficient number of times to merge types of size 1 bit, 393 // then 2 bits, then 4, etc. up to half of the target vector width of the 394 // target vector register. 395 unsigned n = 1; 396 for (unsigned v = 2; 397 (VTTI || v <= Config.VectorBits) && 398 (!Config.MaxIter || n <= Config.MaxIter); 399 v *= 2, ++n) { 400 DEBUG(dbgs() << "BBV: fusing loop #" << n << 401 " for " << BB.getName() << " in " << 402 BB.getParent()->getName() << "...\n"); 403 if (vectorizePairs(BB)) 404 changed = true; 405 else 406 break; 407 } 408 409 if (changed && !Pow2LenOnly) { 410 ++n; 411 for (; !Config.MaxIter || n <= Config.MaxIter; ++n) { 412 DEBUG(dbgs() << "BBV: fusing for non-2^n-length vectors loop #: " << 413 n << " for " << BB.getName() << " in " << 414 BB.getParent()->getName() << "...\n"); 415 if (!vectorizePairs(BB, true)) break; 416 } 417 } 418 419 DEBUG(dbgs() << "BBV: done!\n"); 420 return changed; 421 } 422 423 virtual bool runOnBasicBlock(BasicBlock &BB) { 424 AA = &getAnalysis<AliasAnalysis>(); 425 DT = &getAnalysis<DominatorTree>(); 426 SE = &getAnalysis<ScalarEvolution>(); 427 TD = getAnalysisIfAvailable<DataLayout>(); 428 TTI = IgnoreTargetInfo ? 0 : 429 getAnalysisIfAvailable<TargetTransformInfo>(); 430 VTTI = TTI ? TTI->getVectorTargetTransformInfo() : 0; 431 432 return vectorizeBB(BB); 433 } 434 435 virtual void getAnalysisUsage(AnalysisUsage &AU) const { 436 BasicBlockPass::getAnalysisUsage(AU); 437 AU.addRequired<AliasAnalysis>(); 438 AU.addRequired<DominatorTree>(); 439 AU.addRequired<ScalarEvolution>(); 440 AU.addPreserved<AliasAnalysis>(); 441 AU.addPreserved<DominatorTree>(); 442 AU.addPreserved<ScalarEvolution>(); 443 AU.setPreservesCFG(); 444 } 445 446 static inline VectorType *getVecTypeForPair(Type *ElemTy, Type *Elem2Ty) { 447 assert(ElemTy->getScalarType() == Elem2Ty->getScalarType() && 448 "Cannot form vector from incompatible scalar types"); 449 Type *STy = ElemTy->getScalarType(); 450 451 unsigned numElem; 452 if (VectorType *VTy = dyn_cast<VectorType>(ElemTy)) { 453 numElem = VTy->getNumElements(); 454 } else { 455 numElem = 1; 456 } 457 458 if (VectorType *VTy = dyn_cast<VectorType>(Elem2Ty)) { 459 numElem += VTy->getNumElements(); 460 } else { 461 numElem += 1; 462 } 463 464 return VectorType::get(STy, numElem); 465 } 466 467 static inline void getInstructionTypes(Instruction *I, 468 Type *&T1, Type *&T2) { 469 if (isa<StoreInst>(I)) { 470 // For stores, it is the value type, not the pointer type that matters 471 // because the value is what will come from a vector register. 472 473 Value *IVal = cast<StoreInst>(I)->getValueOperand(); 474 T1 = IVal->getType(); 475 } else { 476 T1 = I->getType(); 477 } 478 479 if (I->isCast()) 480 T2 = cast<CastInst>(I)->getSrcTy(); 481 else 482 T2 = T1; 483 484 if (SelectInst *SI = dyn_cast<SelectInst>(I)) { 485 T2 = SI->getCondition()->getType(); 486 } 487 } 488 489 // Returns the weight associated with the provided value. A chain of 490 // candidate pairs has a length given by the sum of the weights of its 491 // members (one weight per pair; the weight of each member of the pair 492 // is assumed to be the same). This length is then compared to the 493 // chain-length threshold to determine if a given chain is significant 494 // enough to be vectorized. The length is also used in comparing 495 // candidate chains where longer chains are considered to be better. 496 // Note: when this function returns 0, the resulting instructions are 497 // not actually fused. 498 inline size_t getDepthFactor(Value *V) { 499 // InsertElement and ExtractElement have a depth factor of zero. This is 500 // for two reasons: First, they cannot be usefully fused. Second, because 501 // the pass generates a lot of these, they can confuse the simple metric 502 // used to compare the trees in the next iteration. Thus, giving them a 503 // weight of zero allows the pass to essentially ignore them in 504 // subsequent iterations when looking for vectorization opportunities 505 // while still tracking dependency chains that flow through those 506 // instructions. 507 if (isa<InsertElementInst>(V) || isa<ExtractElementInst>(V)) 508 return 0; 509 510 // Give a load or store half of the required depth so that load/store 511 // pairs will vectorize. 512 if (!Config.NoMemOpBoost && (isa<LoadInst>(V) || isa<StoreInst>(V))) 513 return Config.ReqChainDepth/2; 514 515 return 1; 516 } 517 518 // Returns the cost of the provided instruction using VTTI. 519 // This does not handle loads and stores. 520 unsigned getInstrCost(unsigned Opcode, Type *T1, Type *T2) { 521 switch (Opcode) { 522 default: break; 523 case Instruction::GetElementPtr: 524 // We mark this instruction as zero-cost because scalar GEPs are usually 525 // lowered to the intruction addressing mode. At the moment we don't 526 // generate vector GEPs. 527 return 0; 528 case Instruction::Br: 529 return VTTI->getCFInstrCost(Opcode); 530 case Instruction::PHI: 531 return 0; 532 case Instruction::Add: 533 case Instruction::FAdd: 534 case Instruction::Sub: 535 case Instruction::FSub: 536 case Instruction::Mul: 537 case Instruction::FMul: 538 case Instruction::UDiv: 539 case Instruction::SDiv: 540 case Instruction::FDiv: 541 case Instruction::URem: 542 case Instruction::SRem: 543 case Instruction::FRem: 544 case Instruction::Shl: 545 case Instruction::LShr: 546 case Instruction::AShr: 547 case Instruction::And: 548 case Instruction::Or: 549 case Instruction::Xor: 550 return VTTI->getArithmeticInstrCost(Opcode, T1); 551 case Instruction::Select: 552 case Instruction::ICmp: 553 case Instruction::FCmp: 554 return VTTI->getCmpSelInstrCost(Opcode, T1, T2); 555 case Instruction::ZExt: 556 case Instruction::SExt: 557 case Instruction::FPToUI: 558 case Instruction::FPToSI: 559 case Instruction::FPExt: 560 case Instruction::PtrToInt: 561 case Instruction::IntToPtr: 562 case Instruction::SIToFP: 563 case Instruction::UIToFP: 564 case Instruction::Trunc: 565 case Instruction::FPTrunc: 566 case Instruction::BitCast: 567 case Instruction::ShuffleVector: 568 return VTTI->getCastInstrCost(Opcode, T1, T2); 569 } 570 571 return 1; 572 } 573 574 // This determines the relative offset of two loads or stores, returning 575 // true if the offset could be determined to be some constant value. 576 // For example, if OffsetInElmts == 1, then J accesses the memory directly 577 // after I; if OffsetInElmts == -1 then I accesses the memory 578 // directly after J. 579 bool getPairPtrInfo(Instruction *I, Instruction *J, 580 Value *&IPtr, Value *&JPtr, unsigned &IAlignment, unsigned &JAlignment, 581 unsigned &IAddressSpace, unsigned &JAddressSpace, 582 int64_t &OffsetInElmts, bool ComputeOffset = true) { 583 OffsetInElmts = 0; 584 if (LoadInst *LI = dyn_cast<LoadInst>(I)) { 585 LoadInst *LJ = cast<LoadInst>(J); 586 IPtr = LI->getPointerOperand(); 587 JPtr = LJ->getPointerOperand(); 588 IAlignment = LI->getAlignment(); 589 JAlignment = LJ->getAlignment(); 590 IAddressSpace = LI->getPointerAddressSpace(); 591 JAddressSpace = LJ->getPointerAddressSpace(); 592 } else { 593 StoreInst *SI = cast<StoreInst>(I), *SJ = cast<StoreInst>(J); 594 IPtr = SI->getPointerOperand(); 595 JPtr = SJ->getPointerOperand(); 596 IAlignment = SI->getAlignment(); 597 JAlignment = SJ->getAlignment(); 598 IAddressSpace = SI->getPointerAddressSpace(); 599 JAddressSpace = SJ->getPointerAddressSpace(); 600 } 601 602 if (!ComputeOffset) 603 return true; 604 605 const SCEV *IPtrSCEV = SE->getSCEV(IPtr); 606 const SCEV *JPtrSCEV = SE->getSCEV(JPtr); 607 608 // If this is a trivial offset, then we'll get something like 609 // 1*sizeof(type). With target data, which we need anyway, this will get 610 // constant folded into a number. 611 const SCEV *OffsetSCEV = SE->getMinusSCEV(JPtrSCEV, IPtrSCEV); 612 if (const SCEVConstant *ConstOffSCEV = 613 dyn_cast<SCEVConstant>(OffsetSCEV)) { 614 ConstantInt *IntOff = ConstOffSCEV->getValue(); 615 int64_t Offset = IntOff->getSExtValue(); 616 617 Type *VTy = cast<PointerType>(IPtr->getType())->getElementType(); 618 int64_t VTyTSS = (int64_t) TD->getTypeStoreSize(VTy); 619 620 Type *VTy2 = cast<PointerType>(JPtr->getType())->getElementType(); 621 if (VTy != VTy2 && Offset < 0) { 622 int64_t VTy2TSS = (int64_t) TD->getTypeStoreSize(VTy2); 623 OffsetInElmts = Offset/VTy2TSS; 624 return (abs64(Offset) % VTy2TSS) == 0; 625 } 626 627 OffsetInElmts = Offset/VTyTSS; 628 return (abs64(Offset) % VTyTSS) == 0; 629 } 630 631 return false; 632 } 633 634 // Returns true if the provided CallInst represents an intrinsic that can 635 // be vectorized. 636 bool isVectorizableIntrinsic(CallInst* I) { 637 Function *F = I->getCalledFunction(); 638 if (!F) return false; 639 640 unsigned IID = F->getIntrinsicID(); 641 if (!IID) return false; 642 643 switch(IID) { 644 default: 645 return false; 646 case Intrinsic::sqrt: 647 case Intrinsic::powi: 648 case Intrinsic::sin: 649 case Intrinsic::cos: 650 case Intrinsic::log: 651 case Intrinsic::log2: 652 case Intrinsic::log10: 653 case Intrinsic::exp: 654 case Intrinsic::exp2: 655 case Intrinsic::pow: 656 return Config.VectorizeMath; 657 case Intrinsic::fma: 658 return Config.VectorizeFMA; 659 } 660 } 661 662 // Returns true if J is the second element in some pair referenced by 663 // some multimap pair iterator pair. 664 template <typename V> 665 bool isSecondInIteratorPair(V J, std::pair< 666 typename std::multimap<V, V>::iterator, 667 typename std::multimap<V, V>::iterator> PairRange) { 668 for (typename std::multimap<V, V>::iterator K = PairRange.first; 669 K != PairRange.second; ++K) 670 if (K->second == J) return true; 671 672 return false; 673 } 674 }; 675 676 // This function implements one vectorization iteration on the provided 677 // basic block. It returns true if the block is changed. 678 bool BBVectorize::vectorizePairs(BasicBlock &BB, bool NonPow2Len) { 679 bool ShouldContinue; 680 BasicBlock::iterator Start = BB.getFirstInsertionPt(); 681 682 std::vector<Value *> AllPairableInsts; 683 DenseMap<Value *, Value *> AllChosenPairs; 684 DenseSet<ValuePair> AllFixedOrderPairs; 685 DenseMap<VPPair, unsigned> AllPairConnectionTypes; 686 std::multimap<ValuePair, ValuePair> AllConnectedPairs, AllConnectedPairDeps; 687 688 do { 689 std::vector<Value *> PairableInsts; 690 std::multimap<Value *, Value *> CandidatePairs; 691 DenseSet<ValuePair> FixedOrderPairs; 692 DenseMap<ValuePair, int> CandidatePairCostSavings; 693 ShouldContinue = getCandidatePairs(BB, Start, CandidatePairs, 694 FixedOrderPairs, 695 CandidatePairCostSavings, 696 PairableInsts, NonPow2Len); 697 if (PairableInsts.empty()) continue; 698 699 // Now we have a map of all of the pairable instructions and we need to 700 // select the best possible pairing. A good pairing is one such that the 701 // users of the pair are also paired. This defines a (directed) forest 702 // over the pairs such that two pairs are connected iff the second pair 703 // uses the first. 704 705 // Note that it only matters that both members of the second pair use some 706 // element of the first pair (to allow for splatting). 707 708 std::multimap<ValuePair, ValuePair> ConnectedPairs, ConnectedPairDeps; 709 DenseMap<VPPair, unsigned> PairConnectionTypes; 710 computeConnectedPairs(CandidatePairs, PairableInsts, ConnectedPairs, 711 PairConnectionTypes); 712 if (ConnectedPairs.empty()) continue; 713 714 for (std::multimap<ValuePair, ValuePair>::iterator 715 I = ConnectedPairs.begin(), IE = ConnectedPairs.end(); 716 I != IE; ++I) { 717 ConnectedPairDeps.insert(VPPair(I->second, I->first)); 718 } 719 720 // Build the pairable-instruction dependency map 721 DenseSet<ValuePair> PairableInstUsers; 722 buildDepMap(BB, CandidatePairs, PairableInsts, PairableInstUsers); 723 724 // There is now a graph of the connected pairs. For each variable, pick 725 // the pairing with the largest tree meeting the depth requirement on at 726 // least one branch. Then select all pairings that are part of that tree 727 // and remove them from the list of available pairings and pairable 728 // variables. 729 730 DenseMap<Value *, Value *> ChosenPairs; 731 choosePairs(CandidatePairs, CandidatePairCostSavings, 732 PairableInsts, FixedOrderPairs, PairConnectionTypes, 733 ConnectedPairs, ConnectedPairDeps, 734 PairableInstUsers, ChosenPairs); 735 736 if (ChosenPairs.empty()) continue; 737 AllPairableInsts.insert(AllPairableInsts.end(), PairableInsts.begin(), 738 PairableInsts.end()); 739 AllChosenPairs.insert(ChosenPairs.begin(), ChosenPairs.end()); 740 741 // Only for the chosen pairs, propagate information on fixed-order pairs, 742 // pair connections, and their types to the data structures used by the 743 // pair fusion procedures. 744 for (DenseMap<Value *, Value *>::iterator I = ChosenPairs.begin(), 745 IE = ChosenPairs.end(); I != IE; ++I) { 746 if (FixedOrderPairs.count(*I)) 747 AllFixedOrderPairs.insert(*I); 748 else if (FixedOrderPairs.count(ValuePair(I->second, I->first))) 749 AllFixedOrderPairs.insert(ValuePair(I->second, I->first)); 750 751 for (DenseMap<Value *, Value *>::iterator J = ChosenPairs.begin(); 752 J != IE; ++J) { 753 DenseMap<VPPair, unsigned>::iterator K = 754 PairConnectionTypes.find(VPPair(*I, *J)); 755 if (K != PairConnectionTypes.end()) { 756 AllPairConnectionTypes.insert(*K); 757 } else { 758 K = PairConnectionTypes.find(VPPair(*J, *I)); 759 if (K != PairConnectionTypes.end()) 760 AllPairConnectionTypes.insert(*K); 761 } 762 } 763 } 764 765 for (std::multimap<ValuePair, ValuePair>::iterator 766 I = ConnectedPairs.begin(), IE = ConnectedPairs.end(); 767 I != IE; ++I) { 768 if (AllPairConnectionTypes.count(*I)) { 769 AllConnectedPairs.insert(*I); 770 AllConnectedPairDeps.insert(VPPair(I->second, I->first)); 771 } 772 } 773 } while (ShouldContinue); 774 775 if (AllChosenPairs.empty()) return false; 776 NumFusedOps += AllChosenPairs.size(); 777 778 // A set of pairs has now been selected. It is now necessary to replace the 779 // paired instructions with vector instructions. For this procedure each 780 // operand must be replaced with a vector operand. This vector is formed 781 // by using build_vector on the old operands. The replaced values are then 782 // replaced with a vector_extract on the result. Subsequent optimization 783 // passes should coalesce the build/extract combinations. 784 785 fuseChosenPairs(BB, AllPairableInsts, AllChosenPairs, AllFixedOrderPairs, 786 AllPairConnectionTypes, 787 AllConnectedPairs, AllConnectedPairDeps); 788 789 // It is important to cleanup here so that future iterations of this 790 // function have less work to do. 791 (void) SimplifyInstructionsInBlock(&BB, TD, AA->getTargetLibraryInfo()); 792 return true; 793 } 794 795 // This function returns true if the provided instruction is capable of being 796 // fused into a vector instruction. This determination is based only on the 797 // type and other attributes of the instruction. 798 bool BBVectorize::isInstVectorizable(Instruction *I, 799 bool &IsSimpleLoadStore) { 800 IsSimpleLoadStore = false; 801 802 if (CallInst *C = dyn_cast<CallInst>(I)) { 803 if (!isVectorizableIntrinsic(C)) 804 return false; 805 } else if (LoadInst *L = dyn_cast<LoadInst>(I)) { 806 // Vectorize simple loads if possbile: 807 IsSimpleLoadStore = L->isSimple(); 808 if (!IsSimpleLoadStore || !Config.VectorizeMemOps) 809 return false; 810 } else if (StoreInst *S = dyn_cast<StoreInst>(I)) { 811 // Vectorize simple stores if possbile: 812 IsSimpleLoadStore = S->isSimple(); 813 if (!IsSimpleLoadStore || !Config.VectorizeMemOps) 814 return false; 815 } else if (CastInst *C = dyn_cast<CastInst>(I)) { 816 // We can vectorize casts, but not casts of pointer types, etc. 817 if (!Config.VectorizeCasts) 818 return false; 819 820 Type *SrcTy = C->getSrcTy(); 821 if (!SrcTy->isSingleValueType()) 822 return false; 823 824 Type *DestTy = C->getDestTy(); 825 if (!DestTy->isSingleValueType()) 826 return false; 827 } else if (isa<SelectInst>(I)) { 828 if (!Config.VectorizeSelect) 829 return false; 830 } else if (isa<CmpInst>(I)) { 831 if (!Config.VectorizeCmp) 832 return false; 833 } else if (GetElementPtrInst *G = dyn_cast<GetElementPtrInst>(I)) { 834 if (!Config.VectorizeGEP) 835 return false; 836 837 // Currently, vector GEPs exist only with one index. 838 if (G->getNumIndices() != 1) 839 return false; 840 } else if (!(I->isBinaryOp() || isa<ShuffleVectorInst>(I) || 841 isa<ExtractElementInst>(I) || isa<InsertElementInst>(I))) { 842 return false; 843 } 844 845 // We can't vectorize memory operations without target data 846 if (TD == 0 && IsSimpleLoadStore) 847 return false; 848 849 Type *T1, *T2; 850 getInstructionTypes(I, T1, T2); 851 852 // Not every type can be vectorized... 853 if (!(VectorType::isValidElementType(T1) || T1->isVectorTy()) || 854 !(VectorType::isValidElementType(T2) || T2->isVectorTy())) 855 return false; 856 857 if (T1->getScalarSizeInBits() == 1) { 858 if (!Config.VectorizeBools) 859 return false; 860 } else { 861 if (!Config.VectorizeInts && T1->isIntOrIntVectorTy()) 862 return false; 863 } 864 865 if (T2->getScalarSizeInBits() == 1) { 866 if (!Config.VectorizeBools) 867 return false; 868 } else { 869 if (!Config.VectorizeInts && T2->isIntOrIntVectorTy()) 870 return false; 871 } 872 873 if (!Config.VectorizeFloats 874 && (T1->isFPOrFPVectorTy() || T2->isFPOrFPVectorTy())) 875 return false; 876 877 // Don't vectorize target-specific types. 878 if (T1->isX86_FP80Ty() || T1->isPPC_FP128Ty() || T1->isX86_MMXTy()) 879 return false; 880 if (T2->isX86_FP80Ty() || T2->isPPC_FP128Ty() || T2->isX86_MMXTy()) 881 return false; 882 883 if ((!Config.VectorizePointers || TD == 0) && 884 (T1->getScalarType()->isPointerTy() || 885 T2->getScalarType()->isPointerTy())) 886 return false; 887 888 if (!VTTI && (T1->getPrimitiveSizeInBits() >= Config.VectorBits || 889 T2->getPrimitiveSizeInBits() >= Config.VectorBits)) 890 return false; 891 892 return true; 893 } 894 895 // This function returns true if the two provided instructions are compatible 896 // (meaning that they can be fused into a vector instruction). This assumes 897 // that I has already been determined to be vectorizable and that J is not 898 // in the use tree of I. 899 bool BBVectorize::areInstsCompatible(Instruction *I, Instruction *J, 900 bool IsSimpleLoadStore, bool NonPow2Len, 901 int &CostSavings, int &FixedOrder) { 902 DEBUG(if (DebugInstructionExamination) dbgs() << "BBV: looking at " << *I << 903 " <-> " << *J << "\n"); 904 905 CostSavings = 0; 906 FixedOrder = 0; 907 908 // Loads and stores can be merged if they have different alignments, 909 // but are otherwise the same. 910 if (!J->isSameOperationAs(I, Instruction::CompareIgnoringAlignment | 911 (NonPow2Len ? Instruction::CompareUsingScalarTypes : 0))) 912 return false; 913 914 Type *IT1, *IT2, *JT1, *JT2; 915 getInstructionTypes(I, IT1, IT2); 916 getInstructionTypes(J, JT1, JT2); 917 unsigned MaxTypeBits = std::max( 918 IT1->getPrimitiveSizeInBits() + JT1->getPrimitiveSizeInBits(), 919 IT2->getPrimitiveSizeInBits() + JT2->getPrimitiveSizeInBits()); 920 if (!VTTI && MaxTypeBits > Config.VectorBits) 921 return false; 922 923 // FIXME: handle addsub-type operations! 924 925 if (IsSimpleLoadStore) { 926 Value *IPtr, *JPtr; 927 unsigned IAlignment, JAlignment, IAddressSpace, JAddressSpace; 928 int64_t OffsetInElmts = 0; 929 if (getPairPtrInfo(I, J, IPtr, JPtr, IAlignment, JAlignment, 930 IAddressSpace, JAddressSpace, 931 OffsetInElmts) && abs64(OffsetInElmts) == 1) { 932 FixedOrder = (int) OffsetInElmts; 933 unsigned BottomAlignment = IAlignment; 934 if (OffsetInElmts < 0) BottomAlignment = JAlignment; 935 936 Type *aTypeI = isa<StoreInst>(I) ? 937 cast<StoreInst>(I)->getValueOperand()->getType() : I->getType(); 938 Type *aTypeJ = isa<StoreInst>(J) ? 939 cast<StoreInst>(J)->getValueOperand()->getType() : J->getType(); 940 Type *VType = getVecTypeForPair(aTypeI, aTypeJ); 941 942 if (Config.AlignedOnly) { 943 // An aligned load or store is possible only if the instruction 944 // with the lower offset has an alignment suitable for the 945 // vector type. 946 947 unsigned VecAlignment = TD->getPrefTypeAlignment(VType); 948 if (BottomAlignment < VecAlignment) 949 return false; 950 } 951 952 if (VTTI) { 953 unsigned ICost = VTTI->getMemoryOpCost(I->getOpcode(), I->getType(), 954 IAlignment, IAddressSpace); 955 unsigned JCost = VTTI->getMemoryOpCost(J->getOpcode(), J->getType(), 956 JAlignment, JAddressSpace); 957 unsigned VCost = VTTI->getMemoryOpCost(I->getOpcode(), VType, 958 BottomAlignment, 959 IAddressSpace); 960 if (VCost > ICost + JCost) 961 return false; 962 963 // We don't want to fuse to a type that will be split, even 964 // if the two input types will also be split and there is no other 965 // associated cost. 966 unsigned VParts = VTTI->getNumberOfParts(VType); 967 if (VParts > 1) 968 return false; 969 else if (!VParts && VCost == ICost + JCost) 970 return false; 971 972 CostSavings = ICost + JCost - VCost; 973 } 974 } else { 975 return false; 976 } 977 } else if (VTTI) { 978 unsigned ICost = getInstrCost(I->getOpcode(), IT1, IT2); 979 unsigned JCost = getInstrCost(J->getOpcode(), JT1, JT2); 980 Type *VT1 = getVecTypeForPair(IT1, JT1), 981 *VT2 = getVecTypeForPair(IT2, JT2); 982 unsigned VCost = getInstrCost(I->getOpcode(), VT1, VT2); 983 984 if (VCost > ICost + JCost) 985 return false; 986 987 // We don't want to fuse to a type that will be split, even 988 // if the two input types will also be split and there is no other 989 // associated cost. 990 unsigned VParts = VTTI->getNumberOfParts(VT1); 991 if (VParts > 1) 992 return false; 993 else if (!VParts && VCost == ICost + JCost) 994 return false; 995 996 CostSavings = ICost + JCost - VCost; 997 } 998 999 // The powi intrinsic is special because only the first argument is 1000 // vectorized, the second arguments must be equal. 1001 CallInst *CI = dyn_cast<CallInst>(I); 1002 Function *FI; 1003 if (CI && (FI = CI->getCalledFunction()) && 1004 FI->getIntrinsicID() == Intrinsic::powi) { 1005 1006 Value *A1I = CI->getArgOperand(1), 1007 *A1J = cast<CallInst>(J)->getArgOperand(1); 1008 const SCEV *A1ISCEV = SE->getSCEV(A1I), 1009 *A1JSCEV = SE->getSCEV(A1J); 1010 return (A1ISCEV == A1JSCEV); 1011 } 1012 1013 return true; 1014 } 1015 1016 // Figure out whether or not J uses I and update the users and write-set 1017 // structures associated with I. Specifically, Users represents the set of 1018 // instructions that depend on I. WriteSet represents the set 1019 // of memory locations that are dependent on I. If UpdateUsers is true, 1020 // and J uses I, then Users is updated to contain J and WriteSet is updated 1021 // to contain any memory locations to which J writes. The function returns 1022 // true if J uses I. By default, alias analysis is used to determine 1023 // whether J reads from memory that overlaps with a location in WriteSet. 1024 // If LoadMoveSet is not null, then it is a previously-computed multimap 1025 // where the key is the memory-based user instruction and the value is 1026 // the instruction to be compared with I. So, if LoadMoveSet is provided, 1027 // then the alias analysis is not used. This is necessary because this 1028 // function is called during the process of moving instructions during 1029 // vectorization and the results of the alias analysis are not stable during 1030 // that process. 1031 bool BBVectorize::trackUsesOfI(DenseSet<Value *> &Users, 1032 AliasSetTracker &WriteSet, Instruction *I, 1033 Instruction *J, bool UpdateUsers, 1034 std::multimap<Value *, Value *> *LoadMoveSet) { 1035 bool UsesI = false; 1036 1037 // This instruction may already be marked as a user due, for example, to 1038 // being a member of a selected pair. 1039 if (Users.count(J)) 1040 UsesI = true; 1041 1042 if (!UsesI) 1043 for (User::op_iterator JU = J->op_begin(), JE = J->op_end(); 1044 JU != JE; ++JU) { 1045 Value *V = *JU; 1046 if (I == V || Users.count(V)) { 1047 UsesI = true; 1048 break; 1049 } 1050 } 1051 if (!UsesI && J->mayReadFromMemory()) { 1052 if (LoadMoveSet) { 1053 VPIteratorPair JPairRange = LoadMoveSet->equal_range(J); 1054 UsesI = isSecondInIteratorPair<Value*>(I, JPairRange); 1055 } else { 1056 for (AliasSetTracker::iterator W = WriteSet.begin(), 1057 WE = WriteSet.end(); W != WE; ++W) { 1058 if (W->aliasesUnknownInst(J, *AA)) { 1059 UsesI = true; 1060 break; 1061 } 1062 } 1063 } 1064 } 1065 1066 if (UsesI && UpdateUsers) { 1067 if (J->mayWriteToMemory()) WriteSet.add(J); 1068 Users.insert(J); 1069 } 1070 1071 return UsesI; 1072 } 1073 1074 // This function iterates over all instruction pairs in the provided 1075 // basic block and collects all candidate pairs for vectorization. 1076 bool BBVectorize::getCandidatePairs(BasicBlock &BB, 1077 BasicBlock::iterator &Start, 1078 std::multimap<Value *, Value *> &CandidatePairs, 1079 DenseSet<ValuePair> &FixedOrderPairs, 1080 DenseMap<ValuePair, int> &CandidatePairCostSavings, 1081 std::vector<Value *> &PairableInsts, bool NonPow2Len) { 1082 BasicBlock::iterator E = BB.end(); 1083 if (Start == E) return false; 1084 1085 bool ShouldContinue = false, IAfterStart = false; 1086 for (BasicBlock::iterator I = Start++; I != E; ++I) { 1087 if (I == Start) IAfterStart = true; 1088 1089 bool IsSimpleLoadStore; 1090 if (!isInstVectorizable(I, IsSimpleLoadStore)) continue; 1091 1092 // Look for an instruction with which to pair instruction *I... 1093 DenseSet<Value *> Users; 1094 AliasSetTracker WriteSet(*AA); 1095 bool JAfterStart = IAfterStart; 1096 BasicBlock::iterator J = llvm::next(I); 1097 for (unsigned ss = 0; J != E && ss <= Config.SearchLimit; ++J, ++ss) { 1098 if (J == Start) JAfterStart = true; 1099 1100 // Determine if J uses I, if so, exit the loop. 1101 bool UsesI = trackUsesOfI(Users, WriteSet, I, J, !Config.FastDep); 1102 if (Config.FastDep) { 1103 // Note: For this heuristic to be effective, independent operations 1104 // must tend to be intermixed. This is likely to be true from some 1105 // kinds of grouped loop unrolling (but not the generic LLVM pass), 1106 // but otherwise may require some kind of reordering pass. 1107 1108 // When using fast dependency analysis, 1109 // stop searching after first use: 1110 if (UsesI) break; 1111 } else { 1112 if (UsesI) continue; 1113 } 1114 1115 // J does not use I, and comes before the first use of I, so it can be 1116 // merged with I if the instructions are compatible. 1117 int CostSavings, FixedOrder; 1118 if (!areInstsCompatible(I, J, IsSimpleLoadStore, NonPow2Len, 1119 CostSavings, FixedOrder)) continue; 1120 1121 // J is a candidate for merging with I. 1122 if (!PairableInsts.size() || 1123 PairableInsts[PairableInsts.size()-1] != I) { 1124 PairableInsts.push_back(I); 1125 } 1126 1127 CandidatePairs.insert(ValuePair(I, J)); 1128 if (VTTI) 1129 CandidatePairCostSavings.insert(ValuePairWithCost(ValuePair(I, J), 1130 CostSavings)); 1131 1132 if (FixedOrder == 1) 1133 FixedOrderPairs.insert(ValuePair(I, J)); 1134 else if (FixedOrder == -1) 1135 FixedOrderPairs.insert(ValuePair(J, I)); 1136 1137 // The next call to this function must start after the last instruction 1138 // selected during this invocation. 1139 if (JAfterStart) { 1140 Start = llvm::next(J); 1141 IAfterStart = JAfterStart = false; 1142 } 1143 1144 DEBUG(if (DebugCandidateSelection) dbgs() << "BBV: candidate pair " 1145 << *I << " <-> " << *J << " (cost savings: " << 1146 CostSavings << ")\n"); 1147 1148 // If we have already found too many pairs, break here and this function 1149 // will be called again starting after the last instruction selected 1150 // during this invocation. 1151 if (PairableInsts.size() >= Config.MaxInsts) { 1152 ShouldContinue = true; 1153 break; 1154 } 1155 } 1156 1157 if (ShouldContinue) 1158 break; 1159 } 1160 1161 DEBUG(dbgs() << "BBV: found " << PairableInsts.size() 1162 << " instructions with candidate pairs\n"); 1163 1164 return ShouldContinue; 1165 } 1166 1167 // Finds candidate pairs connected to the pair P = <PI, PJ>. This means that 1168 // it looks for pairs such that both members have an input which is an 1169 // output of PI or PJ. 1170 void BBVectorize::computePairsConnectedTo( 1171 std::multimap<Value *, Value *> &CandidatePairs, 1172 std::vector<Value *> &PairableInsts, 1173 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 1174 DenseMap<VPPair, unsigned> &PairConnectionTypes, 1175 ValuePair P) { 1176 StoreInst *SI, *SJ; 1177 1178 // For each possible pairing for this variable, look at the uses of 1179 // the first value... 1180 for (Value::use_iterator I = P.first->use_begin(), 1181 E = P.first->use_end(); I != E; ++I) { 1182 if (isa<LoadInst>(*I)) { 1183 // A pair cannot be connected to a load because the load only takes one 1184 // operand (the address) and it is a scalar even after vectorization. 1185 continue; 1186 } else if ((SI = dyn_cast<StoreInst>(*I)) && 1187 P.first == SI->getPointerOperand()) { 1188 // Similarly, a pair cannot be connected to a store through its 1189 // pointer operand. 1190 continue; 1191 } 1192 1193 VPIteratorPair IPairRange = CandidatePairs.equal_range(*I); 1194 1195 // For each use of the first variable, look for uses of the second 1196 // variable... 1197 for (Value::use_iterator J = P.second->use_begin(), 1198 E2 = P.second->use_end(); J != E2; ++J) { 1199 if ((SJ = dyn_cast<StoreInst>(*J)) && 1200 P.second == SJ->getPointerOperand()) 1201 continue; 1202 1203 VPIteratorPair JPairRange = CandidatePairs.equal_range(*J); 1204 1205 // Look for <I, J>: 1206 if (isSecondInIteratorPair<Value*>(*J, IPairRange)) { 1207 VPPair VP(P, ValuePair(*I, *J)); 1208 ConnectedPairs.insert(VP); 1209 PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionDirect)); 1210 } 1211 1212 // Look for <J, I>: 1213 if (isSecondInIteratorPair<Value*>(*I, JPairRange)) { 1214 VPPair VP(P, ValuePair(*J, *I)); 1215 ConnectedPairs.insert(VP); 1216 PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionSwap)); 1217 } 1218 } 1219 1220 if (Config.SplatBreaksChain) continue; 1221 // Look for cases where just the first value in the pair is used by 1222 // both members of another pair (splatting). 1223 for (Value::use_iterator J = P.first->use_begin(); J != E; ++J) { 1224 if ((SJ = dyn_cast<StoreInst>(*J)) && 1225 P.first == SJ->getPointerOperand()) 1226 continue; 1227 1228 if (isSecondInIteratorPair<Value*>(*J, IPairRange)) { 1229 VPPair VP(P, ValuePair(*I, *J)); 1230 ConnectedPairs.insert(VP); 1231 PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionSplat)); 1232 } 1233 } 1234 } 1235 1236 if (Config.SplatBreaksChain) return; 1237 // Look for cases where just the second value in the pair is used by 1238 // both members of another pair (splatting). 1239 for (Value::use_iterator I = P.second->use_begin(), 1240 E = P.second->use_end(); I != E; ++I) { 1241 if (isa<LoadInst>(*I)) 1242 continue; 1243 else if ((SI = dyn_cast<StoreInst>(*I)) && 1244 P.second == SI->getPointerOperand()) 1245 continue; 1246 1247 VPIteratorPair IPairRange = CandidatePairs.equal_range(*I); 1248 1249 for (Value::use_iterator J = P.second->use_begin(); J != E; ++J) { 1250 if ((SJ = dyn_cast<StoreInst>(*J)) && 1251 P.second == SJ->getPointerOperand()) 1252 continue; 1253 1254 if (isSecondInIteratorPair<Value*>(*J, IPairRange)) { 1255 VPPair VP(P, ValuePair(*I, *J)); 1256 ConnectedPairs.insert(VP); 1257 PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionSplat)); 1258 } 1259 } 1260 } 1261 } 1262 1263 // This function figures out which pairs are connected. Two pairs are 1264 // connected if some output of the first pair forms an input to both members 1265 // of the second pair. 1266 void BBVectorize::computeConnectedPairs( 1267 std::multimap<Value *, Value *> &CandidatePairs, 1268 std::vector<Value *> &PairableInsts, 1269 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 1270 DenseMap<VPPair, unsigned> &PairConnectionTypes) { 1271 1272 for (std::vector<Value *>::iterator PI = PairableInsts.begin(), 1273 PE = PairableInsts.end(); PI != PE; ++PI) { 1274 VPIteratorPair choiceRange = CandidatePairs.equal_range(*PI); 1275 1276 for (std::multimap<Value *, Value *>::iterator P = choiceRange.first; 1277 P != choiceRange.second; ++P) 1278 computePairsConnectedTo(CandidatePairs, PairableInsts, 1279 ConnectedPairs, PairConnectionTypes, *P); 1280 } 1281 1282 DEBUG(dbgs() << "BBV: found " << ConnectedPairs.size() 1283 << " pair connections.\n"); 1284 } 1285 1286 // This function builds a set of use tuples such that <A, B> is in the set 1287 // if B is in the use tree of A. If B is in the use tree of A, then B 1288 // depends on the output of A. 1289 void BBVectorize::buildDepMap( 1290 BasicBlock &BB, 1291 std::multimap<Value *, Value *> &CandidatePairs, 1292 std::vector<Value *> &PairableInsts, 1293 DenseSet<ValuePair> &PairableInstUsers) { 1294 DenseSet<Value *> IsInPair; 1295 for (std::multimap<Value *, Value *>::iterator C = CandidatePairs.begin(), 1296 E = CandidatePairs.end(); C != E; ++C) { 1297 IsInPair.insert(C->first); 1298 IsInPair.insert(C->second); 1299 } 1300 1301 // Iterate through the basic block, recording all Users of each 1302 // pairable instruction. 1303 1304 BasicBlock::iterator E = BB.end(); 1305 for (BasicBlock::iterator I = BB.getFirstInsertionPt(); I != E; ++I) { 1306 if (IsInPair.find(I) == IsInPair.end()) continue; 1307 1308 DenseSet<Value *> Users; 1309 AliasSetTracker WriteSet(*AA); 1310 for (BasicBlock::iterator J = llvm::next(I); J != E; ++J) 1311 (void) trackUsesOfI(Users, WriteSet, I, J); 1312 1313 for (DenseSet<Value *>::iterator U = Users.begin(), E = Users.end(); 1314 U != E; ++U) 1315 PairableInstUsers.insert(ValuePair(I, *U)); 1316 } 1317 } 1318 1319 // Returns true if an input to pair P is an output of pair Q and also an 1320 // input of pair Q is an output of pair P. If this is the case, then these 1321 // two pairs cannot be simultaneously fused. 1322 bool BBVectorize::pairsConflict(ValuePair P, ValuePair Q, 1323 DenseSet<ValuePair> &PairableInstUsers, 1324 std::multimap<ValuePair, ValuePair> *PairableInstUserMap) { 1325 // Two pairs are in conflict if they are mutual Users of eachother. 1326 bool QUsesP = PairableInstUsers.count(ValuePair(P.first, Q.first)) || 1327 PairableInstUsers.count(ValuePair(P.first, Q.second)) || 1328 PairableInstUsers.count(ValuePair(P.second, Q.first)) || 1329 PairableInstUsers.count(ValuePair(P.second, Q.second)); 1330 bool PUsesQ = PairableInstUsers.count(ValuePair(Q.first, P.first)) || 1331 PairableInstUsers.count(ValuePair(Q.first, P.second)) || 1332 PairableInstUsers.count(ValuePair(Q.second, P.first)) || 1333 PairableInstUsers.count(ValuePair(Q.second, P.second)); 1334 if (PairableInstUserMap) { 1335 // FIXME: The expensive part of the cycle check is not so much the cycle 1336 // check itself but this edge insertion procedure. This needs some 1337 // profiling and probably a different data structure (same is true of 1338 // most uses of std::multimap). 1339 if (PUsesQ) { 1340 VPPIteratorPair QPairRange = PairableInstUserMap->equal_range(Q); 1341 if (!isSecondInIteratorPair(P, QPairRange)) 1342 PairableInstUserMap->insert(VPPair(Q, P)); 1343 } 1344 if (QUsesP) { 1345 VPPIteratorPair PPairRange = PairableInstUserMap->equal_range(P); 1346 if (!isSecondInIteratorPair(Q, PPairRange)) 1347 PairableInstUserMap->insert(VPPair(P, Q)); 1348 } 1349 } 1350 1351 return (QUsesP && PUsesQ); 1352 } 1353 1354 // This function walks the use graph of current pairs to see if, starting 1355 // from P, the walk returns to P. 1356 bool BBVectorize::pairWillFormCycle(ValuePair P, 1357 std::multimap<ValuePair, ValuePair> &PairableInstUserMap, 1358 DenseSet<ValuePair> &CurrentPairs) { 1359 DEBUG(if (DebugCycleCheck) 1360 dbgs() << "BBV: starting cycle check for : " << *P.first << " <-> " 1361 << *P.second << "\n"); 1362 // A lookup table of visisted pairs is kept because the PairableInstUserMap 1363 // contains non-direct associations. 1364 DenseSet<ValuePair> Visited; 1365 SmallVector<ValuePair, 32> Q; 1366 // General depth-first post-order traversal: 1367 Q.push_back(P); 1368 do { 1369 ValuePair QTop = Q.pop_back_val(); 1370 Visited.insert(QTop); 1371 1372 DEBUG(if (DebugCycleCheck) 1373 dbgs() << "BBV: cycle check visiting: " << *QTop.first << " <-> " 1374 << *QTop.second << "\n"); 1375 VPPIteratorPair QPairRange = PairableInstUserMap.equal_range(QTop); 1376 for (std::multimap<ValuePair, ValuePair>::iterator C = QPairRange.first; 1377 C != QPairRange.second; ++C) { 1378 if (C->second == P) { 1379 DEBUG(dbgs() 1380 << "BBV: rejected to prevent non-trivial cycle formation: " 1381 << *C->first.first << " <-> " << *C->first.second << "\n"); 1382 return true; 1383 } 1384 1385 if (CurrentPairs.count(C->second) && !Visited.count(C->second)) 1386 Q.push_back(C->second); 1387 } 1388 } while (!Q.empty()); 1389 1390 return false; 1391 } 1392 1393 // This function builds the initial tree of connected pairs with the 1394 // pair J at the root. 1395 void BBVectorize::buildInitialTreeFor( 1396 std::multimap<Value *, Value *> &CandidatePairs, 1397 std::vector<Value *> &PairableInsts, 1398 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 1399 DenseSet<ValuePair> &PairableInstUsers, 1400 DenseMap<Value *, Value *> &ChosenPairs, 1401 DenseMap<ValuePair, size_t> &Tree, ValuePair J) { 1402 // Each of these pairs is viewed as the root node of a Tree. The Tree 1403 // is then walked (depth-first). As this happens, we keep track of 1404 // the pairs that compose the Tree and the maximum depth of the Tree. 1405 SmallVector<ValuePairWithDepth, 32> Q; 1406 // General depth-first post-order traversal: 1407 Q.push_back(ValuePairWithDepth(J, getDepthFactor(J.first))); 1408 do { 1409 ValuePairWithDepth QTop = Q.back(); 1410 1411 // Push each child onto the queue: 1412 bool MoreChildren = false; 1413 size_t MaxChildDepth = QTop.second; 1414 VPPIteratorPair qtRange = ConnectedPairs.equal_range(QTop.first); 1415 for (std::multimap<ValuePair, ValuePair>::iterator k = qtRange.first; 1416 k != qtRange.second; ++k) { 1417 // Make sure that this child pair is still a candidate: 1418 bool IsStillCand = false; 1419 VPIteratorPair checkRange = 1420 CandidatePairs.equal_range(k->second.first); 1421 for (std::multimap<Value *, Value *>::iterator m = checkRange.first; 1422 m != checkRange.second; ++m) { 1423 if (m->second == k->second.second) { 1424 IsStillCand = true; 1425 break; 1426 } 1427 } 1428 1429 if (IsStillCand) { 1430 DenseMap<ValuePair, size_t>::iterator C = Tree.find(k->second); 1431 if (C == Tree.end()) { 1432 size_t d = getDepthFactor(k->second.first); 1433 Q.push_back(ValuePairWithDepth(k->second, QTop.second+d)); 1434 MoreChildren = true; 1435 } else { 1436 MaxChildDepth = std::max(MaxChildDepth, C->second); 1437 } 1438 } 1439 } 1440 1441 if (!MoreChildren) { 1442 // Record the current pair as part of the Tree: 1443 Tree.insert(ValuePairWithDepth(QTop.first, MaxChildDepth)); 1444 Q.pop_back(); 1445 } 1446 } while (!Q.empty()); 1447 } 1448 1449 // Given some initial tree, prune it by removing conflicting pairs (pairs 1450 // that cannot be simultaneously chosen for vectorization). 1451 void BBVectorize::pruneTreeFor( 1452 std::multimap<Value *, Value *> &CandidatePairs, 1453 std::vector<Value *> &PairableInsts, 1454 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 1455 DenseSet<ValuePair> &PairableInstUsers, 1456 std::multimap<ValuePair, ValuePair> &PairableInstUserMap, 1457 DenseMap<Value *, Value *> &ChosenPairs, 1458 DenseMap<ValuePair, size_t> &Tree, 1459 DenseSet<ValuePair> &PrunedTree, ValuePair J, 1460 bool UseCycleCheck) { 1461 SmallVector<ValuePairWithDepth, 32> Q; 1462 // General depth-first post-order traversal: 1463 Q.push_back(ValuePairWithDepth(J, getDepthFactor(J.first))); 1464 do { 1465 ValuePairWithDepth QTop = Q.pop_back_val(); 1466 PrunedTree.insert(QTop.first); 1467 1468 // Visit each child, pruning as necessary... 1469 DenseMap<ValuePair, size_t> BestChildren; 1470 VPPIteratorPair QTopRange = ConnectedPairs.equal_range(QTop.first); 1471 for (std::multimap<ValuePair, ValuePair>::iterator K = QTopRange.first; 1472 K != QTopRange.second; ++K) { 1473 DenseMap<ValuePair, size_t>::iterator C = Tree.find(K->second); 1474 if (C == Tree.end()) continue; 1475 1476 // This child is in the Tree, now we need to make sure it is the 1477 // best of any conflicting children. There could be multiple 1478 // conflicting children, so first, determine if we're keeping 1479 // this child, then delete conflicting children as necessary. 1480 1481 // It is also necessary to guard against pairing-induced 1482 // dependencies. Consider instructions a .. x .. y .. b 1483 // such that (a,b) are to be fused and (x,y) are to be fused 1484 // but a is an input to x and b is an output from y. This 1485 // means that y cannot be moved after b but x must be moved 1486 // after b for (a,b) to be fused. In other words, after 1487 // fusing (a,b) we have y .. a/b .. x where y is an input 1488 // to a/b and x is an output to a/b: x and y can no longer 1489 // be legally fused. To prevent this condition, we must 1490 // make sure that a child pair added to the Tree is not 1491 // both an input and output of an already-selected pair. 1492 1493 // Pairing-induced dependencies can also form from more complicated 1494 // cycles. The pair vs. pair conflicts are easy to check, and so 1495 // that is done explicitly for "fast rejection", and because for 1496 // child vs. child conflicts, we may prefer to keep the current 1497 // pair in preference to the already-selected child. 1498 DenseSet<ValuePair> CurrentPairs; 1499 1500 bool CanAdd = true; 1501 for (DenseMap<ValuePair, size_t>::iterator C2 1502 = BestChildren.begin(), E2 = BestChildren.end(); 1503 C2 != E2; ++C2) { 1504 if (C2->first.first == C->first.first || 1505 C2->first.first == C->first.second || 1506 C2->first.second == C->first.first || 1507 C2->first.second == C->first.second || 1508 pairsConflict(C2->first, C->first, PairableInstUsers, 1509 UseCycleCheck ? &PairableInstUserMap : 0)) { 1510 if (C2->second >= C->second) { 1511 CanAdd = false; 1512 break; 1513 } 1514 1515 CurrentPairs.insert(C2->first); 1516 } 1517 } 1518 if (!CanAdd) continue; 1519 1520 // Even worse, this child could conflict with another node already 1521 // selected for the Tree. If that is the case, ignore this child. 1522 for (DenseSet<ValuePair>::iterator T = PrunedTree.begin(), 1523 E2 = PrunedTree.end(); T != E2; ++T) { 1524 if (T->first == C->first.first || 1525 T->first == C->first.second || 1526 T->second == C->first.first || 1527 T->second == C->first.second || 1528 pairsConflict(*T, C->first, PairableInstUsers, 1529 UseCycleCheck ? &PairableInstUserMap : 0)) { 1530 CanAdd = false; 1531 break; 1532 } 1533 1534 CurrentPairs.insert(*T); 1535 } 1536 if (!CanAdd) continue; 1537 1538 // And check the queue too... 1539 for (SmallVector<ValuePairWithDepth, 32>::iterator C2 = Q.begin(), 1540 E2 = Q.end(); C2 != E2; ++C2) { 1541 if (C2->first.first == C->first.first || 1542 C2->first.first == C->first.second || 1543 C2->first.second == C->first.first || 1544 C2->first.second == C->first.second || 1545 pairsConflict(C2->first, C->first, PairableInstUsers, 1546 UseCycleCheck ? &PairableInstUserMap : 0)) { 1547 CanAdd = false; 1548 break; 1549 } 1550 1551 CurrentPairs.insert(C2->first); 1552 } 1553 if (!CanAdd) continue; 1554 1555 // Last but not least, check for a conflict with any of the 1556 // already-chosen pairs. 1557 for (DenseMap<Value *, Value *>::iterator C2 = 1558 ChosenPairs.begin(), E2 = ChosenPairs.end(); 1559 C2 != E2; ++C2) { 1560 if (pairsConflict(*C2, C->first, PairableInstUsers, 1561 UseCycleCheck ? &PairableInstUserMap : 0)) { 1562 CanAdd = false; 1563 break; 1564 } 1565 1566 CurrentPairs.insert(*C2); 1567 } 1568 if (!CanAdd) continue; 1569 1570 // To check for non-trivial cycles formed by the addition of the 1571 // current pair we've formed a list of all relevant pairs, now use a 1572 // graph walk to check for a cycle. We start from the current pair and 1573 // walk the use tree to see if we again reach the current pair. If we 1574 // do, then the current pair is rejected. 1575 1576 // FIXME: It may be more efficient to use a topological-ordering 1577 // algorithm to improve the cycle check. This should be investigated. 1578 if (UseCycleCheck && 1579 pairWillFormCycle(C->first, PairableInstUserMap, CurrentPairs)) 1580 continue; 1581 1582 // This child can be added, but we may have chosen it in preference 1583 // to an already-selected child. Check for this here, and if a 1584 // conflict is found, then remove the previously-selected child 1585 // before adding this one in its place. 1586 for (DenseMap<ValuePair, size_t>::iterator C2 1587 = BestChildren.begin(); C2 != BestChildren.end();) { 1588 if (C2->first.first == C->first.first || 1589 C2->first.first == C->first.second || 1590 C2->first.second == C->first.first || 1591 C2->first.second == C->first.second || 1592 pairsConflict(C2->first, C->first, PairableInstUsers)) 1593 BestChildren.erase(C2++); 1594 else 1595 ++C2; 1596 } 1597 1598 BestChildren.insert(ValuePairWithDepth(C->first, C->second)); 1599 } 1600 1601 for (DenseMap<ValuePair, size_t>::iterator C 1602 = BestChildren.begin(), E2 = BestChildren.end(); 1603 C != E2; ++C) { 1604 size_t DepthF = getDepthFactor(C->first.first); 1605 Q.push_back(ValuePairWithDepth(C->first, QTop.second+DepthF)); 1606 } 1607 } while (!Q.empty()); 1608 } 1609 1610 // This function finds the best tree of mututally-compatible connected 1611 // pairs, given the choice of root pairs as an iterator range. 1612 void BBVectorize::findBestTreeFor( 1613 std::multimap<Value *, Value *> &CandidatePairs, 1614 DenseMap<ValuePair, int> &CandidatePairCostSavings, 1615 std::vector<Value *> &PairableInsts, 1616 DenseSet<ValuePair> &FixedOrderPairs, 1617 DenseMap<VPPair, unsigned> &PairConnectionTypes, 1618 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 1619 std::multimap<ValuePair, ValuePair> &ConnectedPairDeps, 1620 DenseSet<ValuePair> &PairableInstUsers, 1621 std::multimap<ValuePair, ValuePair> &PairableInstUserMap, 1622 DenseMap<Value *, Value *> &ChosenPairs, 1623 DenseSet<ValuePair> &BestTree, size_t &BestMaxDepth, 1624 int &BestEffSize, VPIteratorPair ChoiceRange, 1625 bool UseCycleCheck) { 1626 for (std::multimap<Value *, Value *>::iterator J = ChoiceRange.first; 1627 J != ChoiceRange.second; ++J) { 1628 1629 // Before going any further, make sure that this pair does not 1630 // conflict with any already-selected pairs (see comment below 1631 // near the Tree pruning for more details). 1632 DenseSet<ValuePair> ChosenPairSet; 1633 bool DoesConflict = false; 1634 for (DenseMap<Value *, Value *>::iterator C = ChosenPairs.begin(), 1635 E = ChosenPairs.end(); C != E; ++C) { 1636 if (pairsConflict(*C, *J, PairableInstUsers, 1637 UseCycleCheck ? &PairableInstUserMap : 0)) { 1638 DoesConflict = true; 1639 break; 1640 } 1641 1642 ChosenPairSet.insert(*C); 1643 } 1644 if (DoesConflict) continue; 1645 1646 if (UseCycleCheck && 1647 pairWillFormCycle(*J, PairableInstUserMap, ChosenPairSet)) 1648 continue; 1649 1650 DenseMap<ValuePair, size_t> Tree; 1651 buildInitialTreeFor(CandidatePairs, PairableInsts, ConnectedPairs, 1652 PairableInstUsers, ChosenPairs, Tree, *J); 1653 1654 // Because we'll keep the child with the largest depth, the largest 1655 // depth is still the same in the unpruned Tree. 1656 size_t MaxDepth = Tree.lookup(*J); 1657 1658 DEBUG(if (DebugPairSelection) dbgs() << "BBV: found Tree for pair {" 1659 << *J->first << " <-> " << *J->second << "} of depth " << 1660 MaxDepth << " and size " << Tree.size() << "\n"); 1661 1662 // At this point the Tree has been constructed, but, may contain 1663 // contradictory children (meaning that different children of 1664 // some tree node may be attempting to fuse the same instruction). 1665 // So now we walk the tree again, in the case of a conflict, 1666 // keep only the child with the largest depth. To break a tie, 1667 // favor the first child. 1668 1669 DenseSet<ValuePair> PrunedTree; 1670 pruneTreeFor(CandidatePairs, PairableInsts, ConnectedPairs, 1671 PairableInstUsers, PairableInstUserMap, ChosenPairs, Tree, 1672 PrunedTree, *J, UseCycleCheck); 1673 1674 int EffSize = 0; 1675 if (VTTI) { 1676 DenseSet<Value *> PrunedTreeInstrs; 1677 for (DenseSet<ValuePair>::iterator S = PrunedTree.begin(), 1678 E = PrunedTree.end(); S != E; ++S) { 1679 PrunedTreeInstrs.insert(S->first); 1680 PrunedTreeInstrs.insert(S->second); 1681 } 1682 1683 // The set of pairs that have already contributed to the total cost. 1684 DenseSet<ValuePair> IncomingPairs; 1685 1686 // The node weights represent the cost savings associated with 1687 // fusing the pair of instructions. 1688 for (DenseSet<ValuePair>::iterator S = PrunedTree.begin(), 1689 E = PrunedTree.end(); S != E; ++S) { 1690 bool FlipOrder = false; 1691 1692 if (getDepthFactor(S->first)) { 1693 int ESContrib = CandidatePairCostSavings.find(*S)->second; 1694 DEBUG(if (DebugPairSelection) dbgs() << "\tweight {" 1695 << *S->first << " <-> " << *S->second << "} = " << 1696 ESContrib << "\n"); 1697 EffSize += ESContrib; 1698 } 1699 1700 // The edge weights contribute in a negative sense: they represent 1701 // the cost of shuffles. 1702 VPPIteratorPair IP = ConnectedPairDeps.equal_range(*S); 1703 if (IP.first != ConnectedPairDeps.end()) { 1704 unsigned NumDepsDirect = 0, NumDepsSwap = 0; 1705 for (std::multimap<ValuePair, ValuePair>::iterator Q = IP.first; 1706 Q != IP.second; ++Q) { 1707 if (!PrunedTree.count(Q->second)) 1708 continue; 1709 DenseMap<VPPair, unsigned>::iterator R = 1710 PairConnectionTypes.find(VPPair(Q->second, Q->first)); 1711 assert(R != PairConnectionTypes.end() && 1712 "Cannot find pair connection type"); 1713 if (R->second == PairConnectionDirect) 1714 ++NumDepsDirect; 1715 else if (R->second == PairConnectionSwap) 1716 ++NumDepsSwap; 1717 } 1718 1719 // If there are more swaps than direct connections, then 1720 // the pair order will be flipped during fusion. So the real 1721 // number of swaps is the minimum number. 1722 FlipOrder = !FixedOrderPairs.count(*S) && 1723 ((NumDepsSwap > NumDepsDirect) || 1724 FixedOrderPairs.count(ValuePair(S->second, S->first))); 1725 1726 for (std::multimap<ValuePair, ValuePair>::iterator Q = IP.first; 1727 Q != IP.second; ++Q) { 1728 if (!PrunedTree.count(Q->second)) 1729 continue; 1730 DenseMap<VPPair, unsigned>::iterator R = 1731 PairConnectionTypes.find(VPPair(Q->second, Q->first)); 1732 assert(R != PairConnectionTypes.end() && 1733 "Cannot find pair connection type"); 1734 Type *Ty1 = Q->second.first->getType(), 1735 *Ty2 = Q->second.second->getType(); 1736 Type *VTy = getVecTypeForPair(Ty1, Ty2); 1737 if ((R->second == PairConnectionDirect && FlipOrder) || 1738 (R->second == PairConnectionSwap && !FlipOrder) || 1739 R->second == PairConnectionSplat) { 1740 int ESContrib = (int) getInstrCost(Instruction::ShuffleVector, 1741 VTy, VTy); 1742 DEBUG(if (DebugPairSelection) dbgs() << "\tcost {" << 1743 *Q->second.first << " <-> " << *Q->second.second << 1744 "} -> {" << 1745 *S->first << " <-> " << *S->second << "} = " << 1746 ESContrib << "\n"); 1747 EffSize -= ESContrib; 1748 } 1749 } 1750 } 1751 1752 // Compute the cost of outgoing edges. We assume that edges outgoing 1753 // to shuffles, inserts or extracts can be merged, and so contribute 1754 // no additional cost. 1755 if (!S->first->getType()->isVoidTy()) { 1756 Type *Ty1 = S->first->getType(), 1757 *Ty2 = S->second->getType(); 1758 Type *VTy = getVecTypeForPair(Ty1, Ty2); 1759 1760 bool NeedsExtraction = false; 1761 for (Value::use_iterator I = S->first->use_begin(), 1762 IE = S->first->use_end(); I != IE; ++I) { 1763 if (isa<ShuffleVectorInst>(*I) || 1764 isa<InsertElementInst>(*I) || 1765 isa<ExtractElementInst>(*I)) 1766 continue; 1767 if (PrunedTreeInstrs.count(*I)) 1768 continue; 1769 NeedsExtraction = true; 1770 break; 1771 } 1772 1773 if (NeedsExtraction) { 1774 int ESContrib; 1775 if (Ty1->isVectorTy()) 1776 ESContrib = (int) getInstrCost(Instruction::ShuffleVector, 1777 Ty1, VTy); 1778 else 1779 ESContrib = (int) VTTI->getVectorInstrCost( 1780 Instruction::ExtractElement, VTy, 0); 1781 1782 DEBUG(if (DebugPairSelection) dbgs() << "\tcost {" << 1783 *S->first << "} = " << ESContrib << "\n"); 1784 EffSize -= ESContrib; 1785 } 1786 1787 NeedsExtraction = false; 1788 for (Value::use_iterator I = S->second->use_begin(), 1789 IE = S->second->use_end(); I != IE; ++I) { 1790 if (isa<ShuffleVectorInst>(*I) || 1791 isa<InsertElementInst>(*I) || 1792 isa<ExtractElementInst>(*I)) 1793 continue; 1794 if (PrunedTreeInstrs.count(*I)) 1795 continue; 1796 NeedsExtraction = true; 1797 break; 1798 } 1799 1800 if (NeedsExtraction) { 1801 int ESContrib; 1802 if (Ty2->isVectorTy()) 1803 ESContrib = (int) getInstrCost(Instruction::ShuffleVector, 1804 Ty2, VTy); 1805 else 1806 ESContrib = (int) VTTI->getVectorInstrCost( 1807 Instruction::ExtractElement, VTy, 1); 1808 DEBUG(if (DebugPairSelection) dbgs() << "\tcost {" << 1809 *S->second << "} = " << ESContrib << "\n"); 1810 EffSize -= ESContrib; 1811 } 1812 } 1813 1814 // Compute the cost of incoming edges. 1815 if (!isa<LoadInst>(S->first) && !isa<StoreInst>(S->first)) { 1816 Instruction *S1 = cast<Instruction>(S->first), 1817 *S2 = cast<Instruction>(S->second); 1818 for (unsigned o = 0; o < S1->getNumOperands(); ++o) { 1819 Value *O1 = S1->getOperand(o), *O2 = S2->getOperand(o); 1820 1821 // Combining constants into vector constants (or small vector 1822 // constants into larger ones are assumed free). 1823 if (isa<Constant>(O1) && isa<Constant>(O2)) 1824 continue; 1825 1826 if (FlipOrder) 1827 std::swap(O1, O2); 1828 1829 ValuePair VP = ValuePair(O1, O2); 1830 ValuePair VPR = ValuePair(O2, O1); 1831 1832 // Internal edges are not handled here. 1833 if (PrunedTree.count(VP) || PrunedTree.count(VPR)) 1834 continue; 1835 1836 Type *Ty1 = O1->getType(), 1837 *Ty2 = O2->getType(); 1838 Type *VTy = getVecTypeForPair(Ty1, Ty2); 1839 1840 // Combining vector operations of the same type is also assumed 1841 // folded with other operations. 1842 if (Ty1 == Ty2 && 1843 (isa<ShuffleVectorInst>(O1) || 1844 isa<InsertElementInst>(O1) || 1845 isa<InsertElementInst>(O1)) && 1846 (isa<ShuffleVectorInst>(O2) || 1847 isa<InsertElementInst>(O2) || 1848 isa<InsertElementInst>(O2))) 1849 continue; 1850 1851 int ESContrib; 1852 // This pair has already been formed. 1853 if (IncomingPairs.count(VP)) { 1854 continue; 1855 } else if (IncomingPairs.count(VPR)) { 1856 ESContrib = (int) getInstrCost(Instruction::ShuffleVector, 1857 VTy, VTy); 1858 } else if (!Ty1->isVectorTy() && !Ty2->isVectorTy()) { 1859 ESContrib = (int) VTTI->getVectorInstrCost( 1860 Instruction::InsertElement, VTy, 0); 1861 ESContrib += (int) VTTI->getVectorInstrCost( 1862 Instruction::InsertElement, VTy, 1); 1863 } else if (!Ty1->isVectorTy()) { 1864 // O1 needs to be inserted into a vector of size O2, and then 1865 // both need to be shuffled together. 1866 ESContrib = (int) VTTI->getVectorInstrCost( 1867 Instruction::InsertElement, Ty2, 0); 1868 ESContrib += (int) getInstrCost(Instruction::ShuffleVector, 1869 VTy, Ty2); 1870 } else if (!Ty2->isVectorTy()) { 1871 // O2 needs to be inserted into a vector of size O1, and then 1872 // both need to be shuffled together. 1873 ESContrib = (int) VTTI->getVectorInstrCost( 1874 Instruction::InsertElement, Ty1, 0); 1875 ESContrib += (int) getInstrCost(Instruction::ShuffleVector, 1876 VTy, Ty1); 1877 } else { 1878 Type *TyBig = Ty1, *TySmall = Ty2; 1879 if (Ty2->getVectorNumElements() > Ty1->getVectorNumElements()) 1880 std::swap(TyBig, TySmall); 1881 1882 ESContrib = (int) getInstrCost(Instruction::ShuffleVector, 1883 VTy, TyBig); 1884 if (TyBig != TySmall) 1885 ESContrib += (int) getInstrCost(Instruction::ShuffleVector, 1886 TyBig, TySmall); 1887 } 1888 1889 DEBUG(if (DebugPairSelection) dbgs() << "\tcost {" 1890 << *O1 << " <-> " << *O2 << "} = " << 1891 ESContrib << "\n"); 1892 EffSize -= ESContrib; 1893 IncomingPairs.insert(VP); 1894 } 1895 } 1896 } 1897 } else { 1898 for (DenseSet<ValuePair>::iterator S = PrunedTree.begin(), 1899 E = PrunedTree.end(); S != E; ++S) 1900 EffSize += (int) getDepthFactor(S->first); 1901 } 1902 1903 DEBUG(if (DebugPairSelection) 1904 dbgs() << "BBV: found pruned Tree for pair {" 1905 << *J->first << " <-> " << *J->second << "} of depth " << 1906 MaxDepth << " and size " << PrunedTree.size() << 1907 " (effective size: " << EffSize << ")\n"); 1908 if (((VTTI && !UseChainDepthWithTI) || 1909 MaxDepth >= Config.ReqChainDepth) && 1910 EffSize > 0 && EffSize > BestEffSize) { 1911 BestMaxDepth = MaxDepth; 1912 BestEffSize = EffSize; 1913 BestTree = PrunedTree; 1914 } 1915 } 1916 } 1917 1918 // Given the list of candidate pairs, this function selects those 1919 // that will be fused into vector instructions. 1920 void BBVectorize::choosePairs( 1921 std::multimap<Value *, Value *> &CandidatePairs, 1922 DenseMap<ValuePair, int> &CandidatePairCostSavings, 1923 std::vector<Value *> &PairableInsts, 1924 DenseSet<ValuePair> &FixedOrderPairs, 1925 DenseMap<VPPair, unsigned> &PairConnectionTypes, 1926 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 1927 std::multimap<ValuePair, ValuePair> &ConnectedPairDeps, 1928 DenseSet<ValuePair> &PairableInstUsers, 1929 DenseMap<Value *, Value *>& ChosenPairs) { 1930 bool UseCycleCheck = 1931 CandidatePairs.size() <= Config.MaxCandPairsForCycleCheck; 1932 std::multimap<ValuePair, ValuePair> PairableInstUserMap; 1933 for (std::vector<Value *>::iterator I = PairableInsts.begin(), 1934 E = PairableInsts.end(); I != E; ++I) { 1935 // The number of possible pairings for this variable: 1936 size_t NumChoices = CandidatePairs.count(*I); 1937 if (!NumChoices) continue; 1938 1939 VPIteratorPair ChoiceRange = CandidatePairs.equal_range(*I); 1940 1941 // The best pair to choose and its tree: 1942 size_t BestMaxDepth = 0; 1943 int BestEffSize = 0; 1944 DenseSet<ValuePair> BestTree; 1945 findBestTreeFor(CandidatePairs, CandidatePairCostSavings, 1946 PairableInsts, FixedOrderPairs, PairConnectionTypes, 1947 ConnectedPairs, ConnectedPairDeps, 1948 PairableInstUsers, PairableInstUserMap, ChosenPairs, 1949 BestTree, BestMaxDepth, BestEffSize, ChoiceRange, 1950 UseCycleCheck); 1951 1952 // A tree has been chosen (or not) at this point. If no tree was 1953 // chosen, then this instruction, I, cannot be paired (and is no longer 1954 // considered). 1955 1956 DEBUG(if (BestTree.size() > 0) 1957 dbgs() << "BBV: selected pairs in the best tree for: " 1958 << *cast<Instruction>(*I) << "\n"); 1959 1960 for (DenseSet<ValuePair>::iterator S = BestTree.begin(), 1961 SE2 = BestTree.end(); S != SE2; ++S) { 1962 // Insert the members of this tree into the list of chosen pairs. 1963 ChosenPairs.insert(ValuePair(S->first, S->second)); 1964 DEBUG(dbgs() << "BBV: selected pair: " << *S->first << " <-> " << 1965 *S->second << "\n"); 1966 1967 // Remove all candidate pairs that have values in the chosen tree. 1968 for (std::multimap<Value *, Value *>::iterator K = 1969 CandidatePairs.begin(); K != CandidatePairs.end();) { 1970 if (K->first == S->first || K->second == S->first || 1971 K->second == S->second || K->first == S->second) { 1972 // Don't remove the actual pair chosen so that it can be used 1973 // in subsequent tree selections. 1974 if (!(K->first == S->first && K->second == S->second)) 1975 CandidatePairs.erase(K++); 1976 else 1977 ++K; 1978 } else { 1979 ++K; 1980 } 1981 } 1982 } 1983 } 1984 1985 DEBUG(dbgs() << "BBV: selected " << ChosenPairs.size() << " pairs.\n"); 1986 } 1987 1988 std::string getReplacementName(Instruction *I, bool IsInput, unsigned o, 1989 unsigned n = 0) { 1990 if (!I->hasName()) 1991 return ""; 1992 1993 return (I->getName() + (IsInput ? ".v.i" : ".v.r") + utostr(o) + 1994 (n > 0 ? "." + utostr(n) : "")).str(); 1995 } 1996 1997 // Returns the value that is to be used as the pointer input to the vector 1998 // instruction that fuses I with J. 1999 Value *BBVectorize::getReplacementPointerInput(LLVMContext& Context, 2000 Instruction *I, Instruction *J, unsigned o) { 2001 Value *IPtr, *JPtr; 2002 unsigned IAlignment, JAlignment, IAddressSpace, JAddressSpace; 2003 int64_t OffsetInElmts; 2004 2005 // Note: the analysis might fail here, that is why the pair order has 2006 // been precomputed (OffsetInElmts must be unused here). 2007 (void) getPairPtrInfo(I, J, IPtr, JPtr, IAlignment, JAlignment, 2008 IAddressSpace, JAddressSpace, 2009 OffsetInElmts, false); 2010 2011 // The pointer value is taken to be the one with the lowest offset. 2012 Value *VPtr = IPtr; 2013 2014 Type *ArgTypeI = cast<PointerType>(IPtr->getType())->getElementType(); 2015 Type *ArgTypeJ = cast<PointerType>(JPtr->getType())->getElementType(); 2016 Type *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ); 2017 Type *VArgPtrType = PointerType::get(VArgType, 2018 cast<PointerType>(IPtr->getType())->getAddressSpace()); 2019 return new BitCastInst(VPtr, VArgPtrType, getReplacementName(I, true, o), 2020 /* insert before */ I); 2021 } 2022 2023 void BBVectorize::fillNewShuffleMask(LLVMContext& Context, Instruction *J, 2024 unsigned MaskOffset, unsigned NumInElem, 2025 unsigned NumInElem1, unsigned IdxOffset, 2026 std::vector<Constant*> &Mask) { 2027 unsigned NumElem1 = cast<VectorType>(J->getType())->getNumElements(); 2028 for (unsigned v = 0; v < NumElem1; ++v) { 2029 int m = cast<ShuffleVectorInst>(J)->getMaskValue(v); 2030 if (m < 0) { 2031 Mask[v+MaskOffset] = UndefValue::get(Type::getInt32Ty(Context)); 2032 } else { 2033 unsigned mm = m + (int) IdxOffset; 2034 if (m >= (int) NumInElem1) 2035 mm += (int) NumInElem; 2036 2037 Mask[v+MaskOffset] = 2038 ConstantInt::get(Type::getInt32Ty(Context), mm); 2039 } 2040 } 2041 } 2042 2043 // Returns the value that is to be used as the vector-shuffle mask to the 2044 // vector instruction that fuses I with J. 2045 Value *BBVectorize::getReplacementShuffleMask(LLVMContext& Context, 2046 Instruction *I, Instruction *J) { 2047 // This is the shuffle mask. We need to append the second 2048 // mask to the first, and the numbers need to be adjusted. 2049 2050 Type *ArgTypeI = I->getType(); 2051 Type *ArgTypeJ = J->getType(); 2052 Type *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ); 2053 2054 unsigned NumElemI = cast<VectorType>(ArgTypeI)->getNumElements(); 2055 2056 // Get the total number of elements in the fused vector type. 2057 // By definition, this must equal the number of elements in 2058 // the final mask. 2059 unsigned NumElem = cast<VectorType>(VArgType)->getNumElements(); 2060 std::vector<Constant*> Mask(NumElem); 2061 2062 Type *OpTypeI = I->getOperand(0)->getType(); 2063 unsigned NumInElemI = cast<VectorType>(OpTypeI)->getNumElements(); 2064 Type *OpTypeJ = J->getOperand(0)->getType(); 2065 unsigned NumInElemJ = cast<VectorType>(OpTypeJ)->getNumElements(); 2066 2067 // The fused vector will be: 2068 // ----------------------------------------------------- 2069 // | NumInElemI | NumInElemJ | NumInElemI | NumInElemJ | 2070 // ----------------------------------------------------- 2071 // from which we'll extract NumElem total elements (where the first NumElemI 2072 // of them come from the mask in I and the remainder come from the mask 2073 // in J. 2074 2075 // For the mask from the first pair... 2076 fillNewShuffleMask(Context, I, 0, NumInElemJ, NumInElemI, 2077 0, Mask); 2078 2079 // For the mask from the second pair... 2080 fillNewShuffleMask(Context, J, NumElemI, NumInElemI, NumInElemJ, 2081 NumInElemI, Mask); 2082 2083 return ConstantVector::get(Mask); 2084 } 2085 2086 bool BBVectorize::expandIEChain(LLVMContext& Context, Instruction *I, 2087 Instruction *J, unsigned o, Value *&LOp, 2088 unsigned numElemL, 2089 Type *ArgTypeL, Type *ArgTypeH, 2090 bool IBeforeJ, unsigned IdxOff) { 2091 bool ExpandedIEChain = false; 2092 if (InsertElementInst *LIE = dyn_cast<InsertElementInst>(LOp)) { 2093 // If we have a pure insertelement chain, then this can be rewritten 2094 // into a chain that directly builds the larger type. 2095 bool PureChain = true; 2096 InsertElementInst *LIENext = LIE; 2097 do { 2098 if (!isa<UndefValue>(LIENext->getOperand(0)) && 2099 !isa<InsertElementInst>(LIENext->getOperand(0))) { 2100 PureChain = false; 2101 break; 2102 } 2103 } while ((LIENext = 2104 dyn_cast<InsertElementInst>(LIENext->getOperand(0)))); 2105 2106 if (PureChain) { 2107 SmallVector<Value *, 8> VectElemts(numElemL, 2108 UndefValue::get(ArgTypeL->getScalarType())); 2109 InsertElementInst *LIENext = LIE; 2110 do { 2111 unsigned Idx = 2112 cast<ConstantInt>(LIENext->getOperand(2))->getSExtValue(); 2113 VectElemts[Idx] = LIENext->getOperand(1); 2114 } while ((LIENext = 2115 dyn_cast<InsertElementInst>(LIENext->getOperand(0)))); 2116 2117 LIENext = 0; 2118 Value *LIEPrev = UndefValue::get(ArgTypeH); 2119 for (unsigned i = 0; i < numElemL; ++i) { 2120 if (isa<UndefValue>(VectElemts[i])) continue; 2121 LIENext = InsertElementInst::Create(LIEPrev, VectElemts[i], 2122 ConstantInt::get(Type::getInt32Ty(Context), 2123 i + IdxOff), 2124 getReplacementName(IBeforeJ ? I : J, 2125 true, o, i+1)); 2126 LIENext->insertBefore(IBeforeJ ? J : I); 2127 LIEPrev = LIENext; 2128 } 2129 2130 LOp = LIENext ? (Value*) LIENext : UndefValue::get(ArgTypeH); 2131 ExpandedIEChain = true; 2132 } 2133 } 2134 2135 return ExpandedIEChain; 2136 } 2137 2138 // Returns the value to be used as the specified operand of the vector 2139 // instruction that fuses I with J. 2140 Value *BBVectorize::getReplacementInput(LLVMContext& Context, Instruction *I, 2141 Instruction *J, unsigned o, bool IBeforeJ) { 2142 Value *CV0 = ConstantInt::get(Type::getInt32Ty(Context), 0); 2143 Value *CV1 = ConstantInt::get(Type::getInt32Ty(Context), 1); 2144 2145 // Compute the fused vector type for this operand 2146 Type *ArgTypeI = I->getOperand(o)->getType(); 2147 Type *ArgTypeJ = J->getOperand(o)->getType(); 2148 VectorType *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ); 2149 2150 Instruction *L = I, *H = J; 2151 Type *ArgTypeL = ArgTypeI, *ArgTypeH = ArgTypeJ; 2152 2153 unsigned numElemL; 2154 if (ArgTypeL->isVectorTy()) 2155 numElemL = cast<VectorType>(ArgTypeL)->getNumElements(); 2156 else 2157 numElemL = 1; 2158 2159 unsigned numElemH; 2160 if (ArgTypeH->isVectorTy()) 2161 numElemH = cast<VectorType>(ArgTypeH)->getNumElements(); 2162 else 2163 numElemH = 1; 2164 2165 Value *LOp = L->getOperand(o); 2166 Value *HOp = H->getOperand(o); 2167 unsigned numElem = VArgType->getNumElements(); 2168 2169 // First, we check if we can reuse the "original" vector outputs (if these 2170 // exist). We might need a shuffle. 2171 ExtractElementInst *LEE = dyn_cast<ExtractElementInst>(LOp); 2172 ExtractElementInst *HEE = dyn_cast<ExtractElementInst>(HOp); 2173 ShuffleVectorInst *LSV = dyn_cast<ShuffleVectorInst>(LOp); 2174 ShuffleVectorInst *HSV = dyn_cast<ShuffleVectorInst>(HOp); 2175 2176 // FIXME: If we're fusing shuffle instructions, then we can't apply this 2177 // optimization. The input vectors to the shuffle might be a different 2178 // length from the shuffle outputs. Unfortunately, the replacement 2179 // shuffle mask has already been formed, and the mask entries are sensitive 2180 // to the sizes of the inputs. 2181 bool IsSizeChangeShuffle = 2182 isa<ShuffleVectorInst>(L) && 2183 (LOp->getType() != L->getType() || HOp->getType() != H->getType()); 2184 2185 if ((LEE || LSV) && (HEE || HSV) && !IsSizeChangeShuffle) { 2186 // We can have at most two unique vector inputs. 2187 bool CanUseInputs = true; 2188 Value *I1, *I2 = 0; 2189 if (LEE) { 2190 I1 = LEE->getOperand(0); 2191 } else { 2192 I1 = LSV->getOperand(0); 2193 I2 = LSV->getOperand(1); 2194 if (I2 == I1 || isa<UndefValue>(I2)) 2195 I2 = 0; 2196 } 2197 2198 if (HEE) { 2199 Value *I3 = HEE->getOperand(0); 2200 if (!I2 && I3 != I1) 2201 I2 = I3; 2202 else if (I3 != I1 && I3 != I2) 2203 CanUseInputs = false; 2204 } else { 2205 Value *I3 = HSV->getOperand(0); 2206 if (!I2 && I3 != I1) 2207 I2 = I3; 2208 else if (I3 != I1 && I3 != I2) 2209 CanUseInputs = false; 2210 2211 if (CanUseInputs) { 2212 Value *I4 = HSV->getOperand(1); 2213 if (!isa<UndefValue>(I4)) { 2214 if (!I2 && I4 != I1) 2215 I2 = I4; 2216 else if (I4 != I1 && I4 != I2) 2217 CanUseInputs = false; 2218 } 2219 } 2220 } 2221 2222 if (CanUseInputs) { 2223 unsigned LOpElem = 2224 cast<VectorType>(cast<Instruction>(LOp)->getOperand(0)->getType()) 2225 ->getNumElements(); 2226 unsigned HOpElem = 2227 cast<VectorType>(cast<Instruction>(HOp)->getOperand(0)->getType()) 2228 ->getNumElements(); 2229 2230 // We have one or two input vectors. We need to map each index of the 2231 // operands to the index of the original vector. 2232 SmallVector<std::pair<int, int>, 8> II(numElem); 2233 for (unsigned i = 0; i < numElemL; ++i) { 2234 int Idx, INum; 2235 if (LEE) { 2236 Idx = 2237 cast<ConstantInt>(LEE->getOperand(1))->getSExtValue(); 2238 INum = LEE->getOperand(0) == I1 ? 0 : 1; 2239 } else { 2240 Idx = LSV->getMaskValue(i); 2241 if (Idx < (int) LOpElem) { 2242 INum = LSV->getOperand(0) == I1 ? 0 : 1; 2243 } else { 2244 Idx -= LOpElem; 2245 INum = LSV->getOperand(1) == I1 ? 0 : 1; 2246 } 2247 } 2248 2249 II[i] = std::pair<int, int>(Idx, INum); 2250 } 2251 for (unsigned i = 0; i < numElemH; ++i) { 2252 int Idx, INum; 2253 if (HEE) { 2254 Idx = 2255 cast<ConstantInt>(HEE->getOperand(1))->getSExtValue(); 2256 INum = HEE->getOperand(0) == I1 ? 0 : 1; 2257 } else { 2258 Idx = HSV->getMaskValue(i); 2259 if (Idx < (int) HOpElem) { 2260 INum = HSV->getOperand(0) == I1 ? 0 : 1; 2261 } else { 2262 Idx -= HOpElem; 2263 INum = HSV->getOperand(1) == I1 ? 0 : 1; 2264 } 2265 } 2266 2267 II[i + numElemL] = std::pair<int, int>(Idx, INum); 2268 } 2269 2270 // We now have an array which tells us from which index of which 2271 // input vector each element of the operand comes. 2272 VectorType *I1T = cast<VectorType>(I1->getType()); 2273 unsigned I1Elem = I1T->getNumElements(); 2274 2275 if (!I2) { 2276 // In this case there is only one underlying vector input. Check for 2277 // the trivial case where we can use the input directly. 2278 if (I1Elem == numElem) { 2279 bool ElemInOrder = true; 2280 for (unsigned i = 0; i < numElem; ++i) { 2281 if (II[i].first != (int) i && II[i].first != -1) { 2282 ElemInOrder = false; 2283 break; 2284 } 2285 } 2286 2287 if (ElemInOrder) 2288 return I1; 2289 } 2290 2291 // A shuffle is needed. 2292 std::vector<Constant *> Mask(numElem); 2293 for (unsigned i = 0; i < numElem; ++i) { 2294 int Idx = II[i].first; 2295 if (Idx == -1) 2296 Mask[i] = UndefValue::get(Type::getInt32Ty(Context)); 2297 else 2298 Mask[i] = ConstantInt::get(Type::getInt32Ty(Context), Idx); 2299 } 2300 2301 Instruction *S = 2302 new ShuffleVectorInst(I1, UndefValue::get(I1T), 2303 ConstantVector::get(Mask), 2304 getReplacementName(IBeforeJ ? I : J, 2305 true, o)); 2306 S->insertBefore(IBeforeJ ? J : I); 2307 return S; 2308 } 2309 2310 VectorType *I2T = cast<VectorType>(I2->getType()); 2311 unsigned I2Elem = I2T->getNumElements(); 2312 2313 // This input comes from two distinct vectors. The first step is to 2314 // make sure that both vectors are the same length. If not, the 2315 // smaller one will need to grow before they can be shuffled together. 2316 if (I1Elem < I2Elem) { 2317 std::vector<Constant *> Mask(I2Elem); 2318 unsigned v = 0; 2319 for (; v < I1Elem; ++v) 2320 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v); 2321 for (; v < I2Elem; ++v) 2322 Mask[v] = UndefValue::get(Type::getInt32Ty(Context)); 2323 2324 Instruction *NewI1 = 2325 new ShuffleVectorInst(I1, UndefValue::get(I1T), 2326 ConstantVector::get(Mask), 2327 getReplacementName(IBeforeJ ? I : J, 2328 true, o, 1)); 2329 NewI1->insertBefore(IBeforeJ ? J : I); 2330 I1 = NewI1; 2331 I1T = I2T; 2332 I1Elem = I2Elem; 2333 } else if (I1Elem > I2Elem) { 2334 std::vector<Constant *> Mask(I1Elem); 2335 unsigned v = 0; 2336 for (; v < I2Elem; ++v) 2337 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v); 2338 for (; v < I1Elem; ++v) 2339 Mask[v] = UndefValue::get(Type::getInt32Ty(Context)); 2340 2341 Instruction *NewI2 = 2342 new ShuffleVectorInst(I2, UndefValue::get(I2T), 2343 ConstantVector::get(Mask), 2344 getReplacementName(IBeforeJ ? I : J, 2345 true, o, 1)); 2346 NewI2->insertBefore(IBeforeJ ? J : I); 2347 I2 = NewI2; 2348 I2T = I1T; 2349 I2Elem = I1Elem; 2350 } 2351 2352 // Now that both I1 and I2 are the same length we can shuffle them 2353 // together (and use the result). 2354 std::vector<Constant *> Mask(numElem); 2355 for (unsigned v = 0; v < numElem; ++v) { 2356 if (II[v].first == -1) { 2357 Mask[v] = UndefValue::get(Type::getInt32Ty(Context)); 2358 } else { 2359 int Idx = II[v].first + II[v].second * I1Elem; 2360 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), Idx); 2361 } 2362 } 2363 2364 Instruction *NewOp = 2365 new ShuffleVectorInst(I1, I2, ConstantVector::get(Mask), 2366 getReplacementName(IBeforeJ ? I : J, true, o)); 2367 NewOp->insertBefore(IBeforeJ ? J : I); 2368 return NewOp; 2369 } 2370 } 2371 2372 Type *ArgType = ArgTypeL; 2373 if (numElemL < numElemH) { 2374 if (numElemL == 1 && expandIEChain(Context, I, J, o, HOp, numElemH, 2375 ArgTypeL, VArgType, IBeforeJ, 1)) { 2376 // This is another short-circuit case: we're combining a scalar into 2377 // a vector that is formed by an IE chain. We've just expanded the IE 2378 // chain, now insert the scalar and we're done. 2379 2380 Instruction *S = InsertElementInst::Create(HOp, LOp, CV0, 2381 getReplacementName(IBeforeJ ? I : J, true, o)); 2382 S->insertBefore(IBeforeJ ? J : I); 2383 return S; 2384 } else if (!expandIEChain(Context, I, J, o, LOp, numElemL, ArgTypeL, 2385 ArgTypeH, IBeforeJ)) { 2386 // The two vector inputs to the shuffle must be the same length, 2387 // so extend the smaller vector to be the same length as the larger one. 2388 Instruction *NLOp; 2389 if (numElemL > 1) { 2390 2391 std::vector<Constant *> Mask(numElemH); 2392 unsigned v = 0; 2393 for (; v < numElemL; ++v) 2394 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v); 2395 for (; v < numElemH; ++v) 2396 Mask[v] = UndefValue::get(Type::getInt32Ty(Context)); 2397 2398 NLOp = new ShuffleVectorInst(LOp, UndefValue::get(ArgTypeL), 2399 ConstantVector::get(Mask), 2400 getReplacementName(IBeforeJ ? I : J, 2401 true, o, 1)); 2402 } else { 2403 NLOp = InsertElementInst::Create(UndefValue::get(ArgTypeH), LOp, CV0, 2404 getReplacementName(IBeforeJ ? I : J, 2405 true, o, 1)); 2406 } 2407 2408 NLOp->insertBefore(IBeforeJ ? J : I); 2409 LOp = NLOp; 2410 } 2411 2412 ArgType = ArgTypeH; 2413 } else if (numElemL > numElemH) { 2414 if (numElemH == 1 && expandIEChain(Context, I, J, o, LOp, numElemL, 2415 ArgTypeH, VArgType, IBeforeJ)) { 2416 Instruction *S = 2417 InsertElementInst::Create(LOp, HOp, 2418 ConstantInt::get(Type::getInt32Ty(Context), 2419 numElemL), 2420 getReplacementName(IBeforeJ ? I : J, 2421 true, o)); 2422 S->insertBefore(IBeforeJ ? J : I); 2423 return S; 2424 } else if (!expandIEChain(Context, I, J, o, HOp, numElemH, ArgTypeH, 2425 ArgTypeL, IBeforeJ)) { 2426 Instruction *NHOp; 2427 if (numElemH > 1) { 2428 std::vector<Constant *> Mask(numElemL); 2429 unsigned v = 0; 2430 for (; v < numElemH; ++v) 2431 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v); 2432 for (; v < numElemL; ++v) 2433 Mask[v] = UndefValue::get(Type::getInt32Ty(Context)); 2434 2435 NHOp = new ShuffleVectorInst(HOp, UndefValue::get(ArgTypeH), 2436 ConstantVector::get(Mask), 2437 getReplacementName(IBeforeJ ? I : J, 2438 true, o, 1)); 2439 } else { 2440 NHOp = InsertElementInst::Create(UndefValue::get(ArgTypeL), HOp, CV0, 2441 getReplacementName(IBeforeJ ? I : J, 2442 true, o, 1)); 2443 } 2444 2445 NHOp->insertBefore(IBeforeJ ? J : I); 2446 HOp = NHOp; 2447 } 2448 } 2449 2450 if (ArgType->isVectorTy()) { 2451 unsigned numElem = cast<VectorType>(VArgType)->getNumElements(); 2452 std::vector<Constant*> Mask(numElem); 2453 for (unsigned v = 0; v < numElem; ++v) { 2454 unsigned Idx = v; 2455 // If the low vector was expanded, we need to skip the extra 2456 // undefined entries. 2457 if (v >= numElemL && numElemH > numElemL) 2458 Idx += (numElemH - numElemL); 2459 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), Idx); 2460 } 2461 2462 Instruction *BV = new ShuffleVectorInst(LOp, HOp, 2463 ConstantVector::get(Mask), 2464 getReplacementName(IBeforeJ ? I : J, true, o)); 2465 BV->insertBefore(IBeforeJ ? J : I); 2466 return BV; 2467 } 2468 2469 Instruction *BV1 = InsertElementInst::Create( 2470 UndefValue::get(VArgType), LOp, CV0, 2471 getReplacementName(IBeforeJ ? I : J, 2472 true, o, 1)); 2473 BV1->insertBefore(IBeforeJ ? J : I); 2474 Instruction *BV2 = InsertElementInst::Create(BV1, HOp, CV1, 2475 getReplacementName(IBeforeJ ? I : J, 2476 true, o, 2)); 2477 BV2->insertBefore(IBeforeJ ? J : I); 2478 return BV2; 2479 } 2480 2481 // This function creates an array of values that will be used as the inputs 2482 // to the vector instruction that fuses I with J. 2483 void BBVectorize::getReplacementInputsForPair(LLVMContext& Context, 2484 Instruction *I, Instruction *J, 2485 SmallVector<Value *, 3> &ReplacedOperands, 2486 bool IBeforeJ) { 2487 unsigned NumOperands = I->getNumOperands(); 2488 2489 for (unsigned p = 0, o = NumOperands-1; p < NumOperands; ++p, --o) { 2490 // Iterate backward so that we look at the store pointer 2491 // first and know whether or not we need to flip the inputs. 2492 2493 if (isa<LoadInst>(I) || (o == 1 && isa<StoreInst>(I))) { 2494 // This is the pointer for a load/store instruction. 2495 ReplacedOperands[o] = getReplacementPointerInput(Context, I, J, o); 2496 continue; 2497 } else if (isa<CallInst>(I)) { 2498 Function *F = cast<CallInst>(I)->getCalledFunction(); 2499 unsigned IID = F->getIntrinsicID(); 2500 if (o == NumOperands-1) { 2501 BasicBlock &BB = *I->getParent(); 2502 2503 Module *M = BB.getParent()->getParent(); 2504 Type *ArgTypeI = I->getType(); 2505 Type *ArgTypeJ = J->getType(); 2506 Type *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ); 2507 2508 ReplacedOperands[o] = Intrinsic::getDeclaration(M, 2509 (Intrinsic::ID) IID, VArgType); 2510 continue; 2511 } else if (IID == Intrinsic::powi && o == 1) { 2512 // The second argument of powi is a single integer and we've already 2513 // checked that both arguments are equal. As a result, we just keep 2514 // I's second argument. 2515 ReplacedOperands[o] = I->getOperand(o); 2516 continue; 2517 } 2518 } else if (isa<ShuffleVectorInst>(I) && o == NumOperands-1) { 2519 ReplacedOperands[o] = getReplacementShuffleMask(Context, I, J); 2520 continue; 2521 } 2522 2523 ReplacedOperands[o] = getReplacementInput(Context, I, J, o, IBeforeJ); 2524 } 2525 } 2526 2527 // This function creates two values that represent the outputs of the 2528 // original I and J instructions. These are generally vector shuffles 2529 // or extracts. In many cases, these will end up being unused and, thus, 2530 // eliminated by later passes. 2531 void BBVectorize::replaceOutputsOfPair(LLVMContext& Context, Instruction *I, 2532 Instruction *J, Instruction *K, 2533 Instruction *&InsertionPt, 2534 Instruction *&K1, Instruction *&K2) { 2535 if (isa<StoreInst>(I)) { 2536 AA->replaceWithNewValue(I, K); 2537 AA->replaceWithNewValue(J, K); 2538 } else { 2539 Type *IType = I->getType(); 2540 Type *JType = J->getType(); 2541 2542 VectorType *VType = getVecTypeForPair(IType, JType); 2543 unsigned numElem = VType->getNumElements(); 2544 2545 unsigned numElemI, numElemJ; 2546 if (IType->isVectorTy()) 2547 numElemI = cast<VectorType>(IType)->getNumElements(); 2548 else 2549 numElemI = 1; 2550 2551 if (JType->isVectorTy()) 2552 numElemJ = cast<VectorType>(JType)->getNumElements(); 2553 else 2554 numElemJ = 1; 2555 2556 if (IType->isVectorTy()) { 2557 std::vector<Constant*> Mask1(numElemI), Mask2(numElemI); 2558 for (unsigned v = 0; v < numElemI; ++v) { 2559 Mask1[v] = ConstantInt::get(Type::getInt32Ty(Context), v); 2560 Mask2[v] = ConstantInt::get(Type::getInt32Ty(Context), numElemJ+v); 2561 } 2562 2563 K1 = new ShuffleVectorInst(K, UndefValue::get(VType), 2564 ConstantVector::get( Mask1), 2565 getReplacementName(K, false, 1)); 2566 } else { 2567 Value *CV0 = ConstantInt::get(Type::getInt32Ty(Context), 0); 2568 K1 = ExtractElementInst::Create(K, CV0, 2569 getReplacementName(K, false, 1)); 2570 } 2571 2572 if (JType->isVectorTy()) { 2573 std::vector<Constant*> Mask1(numElemJ), Mask2(numElemJ); 2574 for (unsigned v = 0; v < numElemJ; ++v) { 2575 Mask1[v] = ConstantInt::get(Type::getInt32Ty(Context), v); 2576 Mask2[v] = ConstantInt::get(Type::getInt32Ty(Context), numElemI+v); 2577 } 2578 2579 K2 = new ShuffleVectorInst(K, UndefValue::get(VType), 2580 ConstantVector::get( Mask2), 2581 getReplacementName(K, false, 2)); 2582 } else { 2583 Value *CV1 = ConstantInt::get(Type::getInt32Ty(Context), numElem-1); 2584 K2 = ExtractElementInst::Create(K, CV1, 2585 getReplacementName(K, false, 2)); 2586 } 2587 2588 K1->insertAfter(K); 2589 K2->insertAfter(K1); 2590 InsertionPt = K2; 2591 } 2592 } 2593 2594 // Move all uses of the function I (including pairing-induced uses) after J. 2595 bool BBVectorize::canMoveUsesOfIAfterJ(BasicBlock &BB, 2596 std::multimap<Value *, Value *> &LoadMoveSet, 2597 Instruction *I, Instruction *J) { 2598 // Skip to the first instruction past I. 2599 BasicBlock::iterator L = llvm::next(BasicBlock::iterator(I)); 2600 2601 DenseSet<Value *> Users; 2602 AliasSetTracker WriteSet(*AA); 2603 for (; cast<Instruction>(L) != J; ++L) 2604 (void) trackUsesOfI(Users, WriteSet, I, L, true, &LoadMoveSet); 2605 2606 assert(cast<Instruction>(L) == J && 2607 "Tracking has not proceeded far enough to check for dependencies"); 2608 // If J is now in the use set of I, then trackUsesOfI will return true 2609 // and we have a dependency cycle (and the fusing operation must abort). 2610 return !trackUsesOfI(Users, WriteSet, I, J, true, &LoadMoveSet); 2611 } 2612 2613 // Move all uses of the function I (including pairing-induced uses) after J. 2614 void BBVectorize::moveUsesOfIAfterJ(BasicBlock &BB, 2615 std::multimap<Value *, Value *> &LoadMoveSet, 2616 Instruction *&InsertionPt, 2617 Instruction *I, Instruction *J) { 2618 // Skip to the first instruction past I. 2619 BasicBlock::iterator L = llvm::next(BasicBlock::iterator(I)); 2620 2621 DenseSet<Value *> Users; 2622 AliasSetTracker WriteSet(*AA); 2623 for (; cast<Instruction>(L) != J;) { 2624 if (trackUsesOfI(Users, WriteSet, I, L, true, &LoadMoveSet)) { 2625 // Move this instruction 2626 Instruction *InstToMove = L; ++L; 2627 2628 DEBUG(dbgs() << "BBV: moving: " << *InstToMove << 2629 " to after " << *InsertionPt << "\n"); 2630 InstToMove->removeFromParent(); 2631 InstToMove->insertAfter(InsertionPt); 2632 InsertionPt = InstToMove; 2633 } else { 2634 ++L; 2635 } 2636 } 2637 } 2638 2639 // Collect all load instruction that are in the move set of a given first 2640 // pair member. These loads depend on the first instruction, I, and so need 2641 // to be moved after J (the second instruction) when the pair is fused. 2642 void BBVectorize::collectPairLoadMoveSet(BasicBlock &BB, 2643 DenseMap<Value *, Value *> &ChosenPairs, 2644 std::multimap<Value *, Value *> &LoadMoveSet, 2645 Instruction *I) { 2646 // Skip to the first instruction past I. 2647 BasicBlock::iterator L = llvm::next(BasicBlock::iterator(I)); 2648 2649 DenseSet<Value *> Users; 2650 AliasSetTracker WriteSet(*AA); 2651 2652 // Note: We cannot end the loop when we reach J because J could be moved 2653 // farther down the use chain by another instruction pairing. Also, J 2654 // could be before I if this is an inverted input. 2655 for (BasicBlock::iterator E = BB.end(); cast<Instruction>(L) != E; ++L) { 2656 if (trackUsesOfI(Users, WriteSet, I, L)) { 2657 if (L->mayReadFromMemory()) 2658 LoadMoveSet.insert(ValuePair(L, I)); 2659 } 2660 } 2661 } 2662 2663 // In cases where both load/stores and the computation of their pointers 2664 // are chosen for vectorization, we can end up in a situation where the 2665 // aliasing analysis starts returning different query results as the 2666 // process of fusing instruction pairs continues. Because the algorithm 2667 // relies on finding the same use trees here as were found earlier, we'll 2668 // need to precompute the necessary aliasing information here and then 2669 // manually update it during the fusion process. 2670 void BBVectorize::collectLoadMoveSet(BasicBlock &BB, 2671 std::vector<Value *> &PairableInsts, 2672 DenseMap<Value *, Value *> &ChosenPairs, 2673 std::multimap<Value *, Value *> &LoadMoveSet) { 2674 for (std::vector<Value *>::iterator PI = PairableInsts.begin(), 2675 PIE = PairableInsts.end(); PI != PIE; ++PI) { 2676 DenseMap<Value *, Value *>::iterator P = ChosenPairs.find(*PI); 2677 if (P == ChosenPairs.end()) continue; 2678 2679 Instruction *I = cast<Instruction>(P->first); 2680 collectPairLoadMoveSet(BB, ChosenPairs, LoadMoveSet, I); 2681 } 2682 } 2683 2684 // When the first instruction in each pair is cloned, it will inherit its 2685 // parent's metadata. This metadata must be combined with that of the other 2686 // instruction in a safe way. 2687 void BBVectorize::combineMetadata(Instruction *K, const Instruction *J) { 2688 SmallVector<std::pair<unsigned, MDNode*>, 4> Metadata; 2689 K->getAllMetadataOtherThanDebugLoc(Metadata); 2690 for (unsigned i = 0, n = Metadata.size(); i < n; ++i) { 2691 unsigned Kind = Metadata[i].first; 2692 MDNode *JMD = J->getMetadata(Kind); 2693 MDNode *KMD = Metadata[i].second; 2694 2695 switch (Kind) { 2696 default: 2697 K->setMetadata(Kind, 0); // Remove unknown metadata 2698 break; 2699 case LLVMContext::MD_tbaa: 2700 K->setMetadata(Kind, MDNode::getMostGenericTBAA(JMD, KMD)); 2701 break; 2702 case LLVMContext::MD_fpmath: 2703 K->setMetadata(Kind, MDNode::getMostGenericFPMath(JMD, KMD)); 2704 break; 2705 } 2706 } 2707 } 2708 2709 // This function fuses the chosen instruction pairs into vector instructions, 2710 // taking care preserve any needed scalar outputs and, then, it reorders the 2711 // remaining instructions as needed (users of the first member of the pair 2712 // need to be moved to after the location of the second member of the pair 2713 // because the vector instruction is inserted in the location of the pair's 2714 // second member). 2715 void BBVectorize::fuseChosenPairs(BasicBlock &BB, 2716 std::vector<Value *> &PairableInsts, 2717 DenseMap<Value *, Value *> &ChosenPairs, 2718 DenseSet<ValuePair> &FixedOrderPairs, 2719 DenseMap<VPPair, unsigned> &PairConnectionTypes, 2720 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 2721 std::multimap<ValuePair, ValuePair> &ConnectedPairDeps) { 2722 LLVMContext& Context = BB.getContext(); 2723 2724 // During the vectorization process, the order of the pairs to be fused 2725 // could be flipped. So we'll add each pair, flipped, into the ChosenPairs 2726 // list. After a pair is fused, the flipped pair is removed from the list. 2727 DenseSet<ValuePair> FlippedPairs; 2728 for (DenseMap<Value *, Value *>::iterator P = ChosenPairs.begin(), 2729 E = ChosenPairs.end(); P != E; ++P) 2730 FlippedPairs.insert(ValuePair(P->second, P->first)); 2731 for (DenseSet<ValuePair>::iterator P = FlippedPairs.begin(), 2732 E = FlippedPairs.end(); P != E; ++P) 2733 ChosenPairs.insert(*P); 2734 2735 std::multimap<Value *, Value *> LoadMoveSet; 2736 collectLoadMoveSet(BB, PairableInsts, ChosenPairs, LoadMoveSet); 2737 2738 DEBUG(dbgs() << "BBV: initial: \n" << BB << "\n"); 2739 2740 for (BasicBlock::iterator PI = BB.getFirstInsertionPt(); PI != BB.end();) { 2741 DenseMap<Value *, Value *>::iterator P = ChosenPairs.find(PI); 2742 if (P == ChosenPairs.end()) { 2743 ++PI; 2744 continue; 2745 } 2746 2747 if (getDepthFactor(P->first) == 0) { 2748 // These instructions are not really fused, but are tracked as though 2749 // they are. Any case in which it would be interesting to fuse them 2750 // will be taken care of by InstCombine. 2751 --NumFusedOps; 2752 ++PI; 2753 continue; 2754 } 2755 2756 Instruction *I = cast<Instruction>(P->first), 2757 *J = cast<Instruction>(P->second); 2758 2759 DEBUG(dbgs() << "BBV: fusing: " << *I << 2760 " <-> " << *J << "\n"); 2761 2762 // Remove the pair and flipped pair from the list. 2763 DenseMap<Value *, Value *>::iterator FP = ChosenPairs.find(P->second); 2764 assert(FP != ChosenPairs.end() && "Flipped pair not found in list"); 2765 ChosenPairs.erase(FP); 2766 ChosenPairs.erase(P); 2767 2768 if (!canMoveUsesOfIAfterJ(BB, LoadMoveSet, I, J)) { 2769 DEBUG(dbgs() << "BBV: fusion of: " << *I << 2770 " <-> " << *J << 2771 " aborted because of non-trivial dependency cycle\n"); 2772 --NumFusedOps; 2773 ++PI; 2774 continue; 2775 } 2776 2777 // If the pair must have the other order, then flip it. 2778 bool FlipPairOrder = FixedOrderPairs.count(ValuePair(J, I)); 2779 if (!FlipPairOrder && !FixedOrderPairs.count(ValuePair(I, J))) { 2780 // This pair does not have a fixed order, and so we might want to 2781 // flip it if that will yield fewer shuffles. We count the number 2782 // of dependencies connected via swaps, and those directly connected, 2783 // and flip the order if the number of swaps is greater. 2784 bool OrigOrder = true; 2785 VPPIteratorPair IP = ConnectedPairDeps.equal_range(ValuePair(I, J)); 2786 if (IP.first == ConnectedPairDeps.end()) { 2787 IP = ConnectedPairDeps.equal_range(ValuePair(J, I)); 2788 OrigOrder = false; 2789 } 2790 2791 if (IP.first != ConnectedPairDeps.end()) { 2792 unsigned NumDepsDirect = 0, NumDepsSwap = 0; 2793 for (std::multimap<ValuePair, ValuePair>::iterator Q = IP.first; 2794 Q != IP.second; ++Q) { 2795 DenseMap<VPPair, unsigned>::iterator R = 2796 PairConnectionTypes.find(VPPair(Q->second, Q->first)); 2797 assert(R != PairConnectionTypes.end() && 2798 "Cannot find pair connection type"); 2799 if (R->second == PairConnectionDirect) 2800 ++NumDepsDirect; 2801 else if (R->second == PairConnectionSwap) 2802 ++NumDepsSwap; 2803 } 2804 2805 if (!OrigOrder) 2806 std::swap(NumDepsDirect, NumDepsSwap); 2807 2808 if (NumDepsSwap > NumDepsDirect) { 2809 FlipPairOrder = true; 2810 DEBUG(dbgs() << "BBV: reordering pair: " << *I << 2811 " <-> " << *J << "\n"); 2812 } 2813 } 2814 } 2815 2816 Instruction *L = I, *H = J; 2817 if (FlipPairOrder) 2818 std::swap(H, L); 2819 2820 // If the pair being fused uses the opposite order from that in the pair 2821 // connection map, then we need to flip the types. 2822 VPPIteratorPair IP = ConnectedPairs.equal_range(ValuePair(H, L)); 2823 for (std::multimap<ValuePair, ValuePair>::iterator Q = IP.first; 2824 Q != IP.second; ++Q) { 2825 DenseMap<VPPair, unsigned>::iterator R = PairConnectionTypes.find(*Q); 2826 assert(R != PairConnectionTypes.end() && 2827 "Cannot find pair connection type"); 2828 if (R->second == PairConnectionDirect) 2829 R->second = PairConnectionSwap; 2830 else if (R->second == PairConnectionSwap) 2831 R->second = PairConnectionDirect; 2832 } 2833 2834 bool LBeforeH = !FlipPairOrder; 2835 unsigned NumOperands = I->getNumOperands(); 2836 SmallVector<Value *, 3> ReplacedOperands(NumOperands); 2837 getReplacementInputsForPair(Context, L, H, ReplacedOperands, 2838 LBeforeH); 2839 2840 // Make a copy of the original operation, change its type to the vector 2841 // type and replace its operands with the vector operands. 2842 Instruction *K = L->clone(); 2843 if (L->hasName()) 2844 K->takeName(L); 2845 else if (H->hasName()) 2846 K->takeName(H); 2847 2848 if (!isa<StoreInst>(K)) 2849 K->mutateType(getVecTypeForPair(L->getType(), H->getType())); 2850 2851 combineMetadata(K, H); 2852 2853 for (unsigned o = 0; o < NumOperands; ++o) 2854 K->setOperand(o, ReplacedOperands[o]); 2855 2856 K->insertAfter(J); 2857 2858 // Instruction insertion point: 2859 Instruction *InsertionPt = K; 2860 Instruction *K1 = 0, *K2 = 0; 2861 replaceOutputsOfPair(Context, L, H, K, InsertionPt, K1, K2); 2862 2863 // The use tree of the first original instruction must be moved to after 2864 // the location of the second instruction. The entire use tree of the 2865 // first instruction is disjoint from the input tree of the second 2866 // (by definition), and so commutes with it. 2867 2868 moveUsesOfIAfterJ(BB, LoadMoveSet, InsertionPt, I, J); 2869 2870 if (!isa<StoreInst>(I)) { 2871 L->replaceAllUsesWith(K1); 2872 H->replaceAllUsesWith(K2); 2873 AA->replaceWithNewValue(L, K1); 2874 AA->replaceWithNewValue(H, K2); 2875 } 2876 2877 // Instructions that may read from memory may be in the load move set. 2878 // Once an instruction is fused, we no longer need its move set, and so 2879 // the values of the map never need to be updated. However, when a load 2880 // is fused, we need to merge the entries from both instructions in the 2881 // pair in case those instructions were in the move set of some other 2882 // yet-to-be-fused pair. The loads in question are the keys of the map. 2883 if (I->mayReadFromMemory()) { 2884 std::vector<ValuePair> NewSetMembers; 2885 VPIteratorPair IPairRange = LoadMoveSet.equal_range(I); 2886 VPIteratorPair JPairRange = LoadMoveSet.equal_range(J); 2887 for (std::multimap<Value *, Value *>::iterator N = IPairRange.first; 2888 N != IPairRange.second; ++N) 2889 NewSetMembers.push_back(ValuePair(K, N->second)); 2890 for (std::multimap<Value *, Value *>::iterator N = JPairRange.first; 2891 N != JPairRange.second; ++N) 2892 NewSetMembers.push_back(ValuePair(K, N->second)); 2893 for (std::vector<ValuePair>::iterator A = NewSetMembers.begin(), 2894 AE = NewSetMembers.end(); A != AE; ++A) 2895 LoadMoveSet.insert(*A); 2896 } 2897 2898 // Before removing I, set the iterator to the next instruction. 2899 PI = llvm::next(BasicBlock::iterator(I)); 2900 if (cast<Instruction>(PI) == J) 2901 ++PI; 2902 2903 SE->forgetValue(I); 2904 SE->forgetValue(J); 2905 I->eraseFromParent(); 2906 J->eraseFromParent(); 2907 2908 DEBUG(if (PrintAfterEveryPair) dbgs() << "BBV: block is now: \n" << 2909 BB << "\n"); 2910 } 2911 2912 DEBUG(dbgs() << "BBV: final: \n" << BB << "\n"); 2913 } 2914} 2915 2916char BBVectorize::ID = 0; 2917static const char bb_vectorize_name[] = "Basic-Block Vectorization"; 2918INITIALIZE_PASS_BEGIN(BBVectorize, BBV_NAME, bb_vectorize_name, false, false) 2919INITIALIZE_AG_DEPENDENCY(AliasAnalysis) 2920INITIALIZE_PASS_DEPENDENCY(DominatorTree) 2921INITIALIZE_PASS_DEPENDENCY(ScalarEvolution) 2922INITIALIZE_PASS_END(BBVectorize, BBV_NAME, bb_vectorize_name, false, false) 2923 2924BasicBlockPass *llvm::createBBVectorizePass(const VectorizeConfig &C) { 2925 return new BBVectorize(C); 2926} 2927 2928bool 2929llvm::vectorizeBasicBlock(Pass *P, BasicBlock &BB, const VectorizeConfig &C) { 2930 BBVectorize BBVectorizer(P, C); 2931 return BBVectorizer.vectorizeBB(BB); 2932} 2933 2934//===----------------------------------------------------------------------===// 2935VectorizeConfig::VectorizeConfig() { 2936 VectorBits = ::VectorBits; 2937 VectorizeBools = !::NoBools; 2938 VectorizeInts = !::NoInts; 2939 VectorizeFloats = !::NoFloats; 2940 VectorizePointers = !::NoPointers; 2941 VectorizeCasts = !::NoCasts; 2942 VectorizeMath = !::NoMath; 2943 VectorizeFMA = !::NoFMA; 2944 VectorizeSelect = !::NoSelect; 2945 VectorizeCmp = !::NoCmp; 2946 VectorizeGEP = !::NoGEP; 2947 VectorizeMemOps = !::NoMemOps; 2948 AlignedOnly = ::AlignedOnly; 2949 ReqChainDepth= ::ReqChainDepth; 2950 SearchLimit = ::SearchLimit; 2951 MaxCandPairsForCycleCheck = ::MaxCandPairsForCycleCheck; 2952 SplatBreaksChain = ::SplatBreaksChain; 2953 MaxInsts = ::MaxInsts; 2954 MaxIter = ::MaxIter; 2955 Pow2LenOnly = ::Pow2LenOnly; 2956 NoMemOpBoost = ::NoMemOpBoost; 2957 FastDep = ::FastDep; 2958} 2959