BBVectorize.cpp revision 5094257518ea7b615d87ef5bea657625ffa81991
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 } else if (ShuffleVectorInst *SI = dyn_cast<ShuffleVectorInst>(I)) { 487 T2 = SI->getOperand(0)->getType(); 488 } else if (CmpInst *CI = dyn_cast<CmpInst>(I)) { 489 T2 = CI->getOperand(0)->getType(); 490 } 491 } 492 493 // Returns the weight associated with the provided value. A chain of 494 // candidate pairs has a length given by the sum of the weights of its 495 // members (one weight per pair; the weight of each member of the pair 496 // is assumed to be the same). This length is then compared to the 497 // chain-length threshold to determine if a given chain is significant 498 // enough to be vectorized. The length is also used in comparing 499 // candidate chains where longer chains are considered to be better. 500 // Note: when this function returns 0, the resulting instructions are 501 // not actually fused. 502 inline size_t getDepthFactor(Value *V) { 503 // InsertElement and ExtractElement have a depth factor of zero. This is 504 // for two reasons: First, they cannot be usefully fused. Second, because 505 // the pass generates a lot of these, they can confuse the simple metric 506 // used to compare the trees in the next iteration. Thus, giving them a 507 // weight of zero allows the pass to essentially ignore them in 508 // subsequent iterations when looking for vectorization opportunities 509 // while still tracking dependency chains that flow through those 510 // instructions. 511 if (isa<InsertElementInst>(V) || isa<ExtractElementInst>(V)) 512 return 0; 513 514 // Give a load or store half of the required depth so that load/store 515 // pairs will vectorize. 516 if (!Config.NoMemOpBoost && (isa<LoadInst>(V) || isa<StoreInst>(V))) 517 return Config.ReqChainDepth/2; 518 519 return 1; 520 } 521 522 // Returns the cost of the provided instruction using VTTI. 523 // This does not handle loads and stores. 524 unsigned getInstrCost(unsigned Opcode, Type *T1, Type *T2) { 525 switch (Opcode) { 526 default: break; 527 case Instruction::GetElementPtr: 528 // We mark this instruction as zero-cost because scalar GEPs are usually 529 // lowered to the intruction addressing mode. At the moment we don't 530 // generate vector GEPs. 531 return 0; 532 case Instruction::Br: 533 return VTTI->getCFInstrCost(Opcode); 534 case Instruction::PHI: 535 return 0; 536 case Instruction::Add: 537 case Instruction::FAdd: 538 case Instruction::Sub: 539 case Instruction::FSub: 540 case Instruction::Mul: 541 case Instruction::FMul: 542 case Instruction::UDiv: 543 case Instruction::SDiv: 544 case Instruction::FDiv: 545 case Instruction::URem: 546 case Instruction::SRem: 547 case Instruction::FRem: 548 case Instruction::Shl: 549 case Instruction::LShr: 550 case Instruction::AShr: 551 case Instruction::And: 552 case Instruction::Or: 553 case Instruction::Xor: 554 return VTTI->getArithmeticInstrCost(Opcode, T1); 555 case Instruction::Select: 556 case Instruction::ICmp: 557 case Instruction::FCmp: 558 return VTTI->getCmpSelInstrCost(Opcode, T1, T2); 559 case Instruction::ZExt: 560 case Instruction::SExt: 561 case Instruction::FPToUI: 562 case Instruction::FPToSI: 563 case Instruction::FPExt: 564 case Instruction::PtrToInt: 565 case Instruction::IntToPtr: 566 case Instruction::SIToFP: 567 case Instruction::UIToFP: 568 case Instruction::Trunc: 569 case Instruction::FPTrunc: 570 case Instruction::BitCast: 571 case Instruction::ShuffleVector: 572 return VTTI->getCastInstrCost(Opcode, T1, T2); 573 } 574 575 return 1; 576 } 577 578 // This determines the relative offset of two loads or stores, returning 579 // true if the offset could be determined to be some constant value. 580 // For example, if OffsetInElmts == 1, then J accesses the memory directly 581 // after I; if OffsetInElmts == -1 then I accesses the memory 582 // directly after J. 583 bool getPairPtrInfo(Instruction *I, Instruction *J, 584 Value *&IPtr, Value *&JPtr, unsigned &IAlignment, unsigned &JAlignment, 585 unsigned &IAddressSpace, unsigned &JAddressSpace, 586 int64_t &OffsetInElmts, bool ComputeOffset = true) { 587 OffsetInElmts = 0; 588 if (LoadInst *LI = dyn_cast<LoadInst>(I)) { 589 LoadInst *LJ = cast<LoadInst>(J); 590 IPtr = LI->getPointerOperand(); 591 JPtr = LJ->getPointerOperand(); 592 IAlignment = LI->getAlignment(); 593 JAlignment = LJ->getAlignment(); 594 IAddressSpace = LI->getPointerAddressSpace(); 595 JAddressSpace = LJ->getPointerAddressSpace(); 596 } else { 597 StoreInst *SI = cast<StoreInst>(I), *SJ = cast<StoreInst>(J); 598 IPtr = SI->getPointerOperand(); 599 JPtr = SJ->getPointerOperand(); 600 IAlignment = SI->getAlignment(); 601 JAlignment = SJ->getAlignment(); 602 IAddressSpace = SI->getPointerAddressSpace(); 603 JAddressSpace = SJ->getPointerAddressSpace(); 604 } 605 606 if (!ComputeOffset) 607 return true; 608 609 const SCEV *IPtrSCEV = SE->getSCEV(IPtr); 610 const SCEV *JPtrSCEV = SE->getSCEV(JPtr); 611 612 // If this is a trivial offset, then we'll get something like 613 // 1*sizeof(type). With target data, which we need anyway, this will get 614 // constant folded into a number. 615 const SCEV *OffsetSCEV = SE->getMinusSCEV(JPtrSCEV, IPtrSCEV); 616 if (const SCEVConstant *ConstOffSCEV = 617 dyn_cast<SCEVConstant>(OffsetSCEV)) { 618 ConstantInt *IntOff = ConstOffSCEV->getValue(); 619 int64_t Offset = IntOff->getSExtValue(); 620 621 Type *VTy = cast<PointerType>(IPtr->getType())->getElementType(); 622 int64_t VTyTSS = (int64_t) TD->getTypeStoreSize(VTy); 623 624 Type *VTy2 = cast<PointerType>(JPtr->getType())->getElementType(); 625 if (VTy != VTy2 && Offset < 0) { 626 int64_t VTy2TSS = (int64_t) TD->getTypeStoreSize(VTy2); 627 OffsetInElmts = Offset/VTy2TSS; 628 return (abs64(Offset) % VTy2TSS) == 0; 629 } 630 631 OffsetInElmts = Offset/VTyTSS; 632 return (abs64(Offset) % VTyTSS) == 0; 633 } 634 635 return false; 636 } 637 638 // Returns true if the provided CallInst represents an intrinsic that can 639 // be vectorized. 640 bool isVectorizableIntrinsic(CallInst* I) { 641 Function *F = I->getCalledFunction(); 642 if (!F) return false; 643 644 unsigned IID = F->getIntrinsicID(); 645 if (!IID) return false; 646 647 switch(IID) { 648 default: 649 return false; 650 case Intrinsic::sqrt: 651 case Intrinsic::powi: 652 case Intrinsic::sin: 653 case Intrinsic::cos: 654 case Intrinsic::log: 655 case Intrinsic::log2: 656 case Intrinsic::log10: 657 case Intrinsic::exp: 658 case Intrinsic::exp2: 659 case Intrinsic::pow: 660 return Config.VectorizeMath; 661 case Intrinsic::fma: 662 return Config.VectorizeFMA; 663 } 664 } 665 666 // Returns true if J is the second element in some pair referenced by 667 // some multimap pair iterator pair. 668 template <typename V> 669 bool isSecondInIteratorPair(V J, std::pair< 670 typename std::multimap<V, V>::iterator, 671 typename std::multimap<V, V>::iterator> PairRange) { 672 for (typename std::multimap<V, V>::iterator K = PairRange.first; 673 K != PairRange.second; ++K) 674 if (K->second == J) return true; 675 676 return false; 677 } 678 }; 679 680 // This function implements one vectorization iteration on the provided 681 // basic block. It returns true if the block is changed. 682 bool BBVectorize::vectorizePairs(BasicBlock &BB, bool NonPow2Len) { 683 bool ShouldContinue; 684 BasicBlock::iterator Start = BB.getFirstInsertionPt(); 685 686 std::vector<Value *> AllPairableInsts; 687 DenseMap<Value *, Value *> AllChosenPairs; 688 DenseSet<ValuePair> AllFixedOrderPairs; 689 DenseMap<VPPair, unsigned> AllPairConnectionTypes; 690 std::multimap<ValuePair, ValuePair> AllConnectedPairs, AllConnectedPairDeps; 691 692 do { 693 std::vector<Value *> PairableInsts; 694 std::multimap<Value *, Value *> CandidatePairs; 695 DenseSet<ValuePair> FixedOrderPairs; 696 DenseMap<ValuePair, int> CandidatePairCostSavings; 697 ShouldContinue = getCandidatePairs(BB, Start, CandidatePairs, 698 FixedOrderPairs, 699 CandidatePairCostSavings, 700 PairableInsts, NonPow2Len); 701 if (PairableInsts.empty()) continue; 702 703 // Now we have a map of all of the pairable instructions and we need to 704 // select the best possible pairing. A good pairing is one such that the 705 // users of the pair are also paired. This defines a (directed) forest 706 // over the pairs such that two pairs are connected iff the second pair 707 // uses the first. 708 709 // Note that it only matters that both members of the second pair use some 710 // element of the first pair (to allow for splatting). 711 712 std::multimap<ValuePair, ValuePair> ConnectedPairs, ConnectedPairDeps; 713 DenseMap<VPPair, unsigned> PairConnectionTypes; 714 computeConnectedPairs(CandidatePairs, PairableInsts, ConnectedPairs, 715 PairConnectionTypes); 716 if (ConnectedPairs.empty()) continue; 717 718 for (std::multimap<ValuePair, ValuePair>::iterator 719 I = ConnectedPairs.begin(), IE = ConnectedPairs.end(); 720 I != IE; ++I) { 721 ConnectedPairDeps.insert(VPPair(I->second, I->first)); 722 } 723 724 // Build the pairable-instruction dependency map 725 DenseSet<ValuePair> PairableInstUsers; 726 buildDepMap(BB, CandidatePairs, PairableInsts, PairableInstUsers); 727 728 // There is now a graph of the connected pairs. For each variable, pick 729 // the pairing with the largest tree meeting the depth requirement on at 730 // least one branch. Then select all pairings that are part of that tree 731 // and remove them from the list of available pairings and pairable 732 // variables. 733 734 DenseMap<Value *, Value *> ChosenPairs; 735 choosePairs(CandidatePairs, CandidatePairCostSavings, 736 PairableInsts, FixedOrderPairs, PairConnectionTypes, 737 ConnectedPairs, ConnectedPairDeps, 738 PairableInstUsers, ChosenPairs); 739 740 if (ChosenPairs.empty()) continue; 741 AllPairableInsts.insert(AllPairableInsts.end(), PairableInsts.begin(), 742 PairableInsts.end()); 743 AllChosenPairs.insert(ChosenPairs.begin(), ChosenPairs.end()); 744 745 // Only for the chosen pairs, propagate information on fixed-order pairs, 746 // pair connections, and their types to the data structures used by the 747 // pair fusion procedures. 748 for (DenseMap<Value *, Value *>::iterator I = ChosenPairs.begin(), 749 IE = ChosenPairs.end(); I != IE; ++I) { 750 if (FixedOrderPairs.count(*I)) 751 AllFixedOrderPairs.insert(*I); 752 else if (FixedOrderPairs.count(ValuePair(I->second, I->first))) 753 AllFixedOrderPairs.insert(ValuePair(I->second, I->first)); 754 755 for (DenseMap<Value *, Value *>::iterator J = ChosenPairs.begin(); 756 J != IE; ++J) { 757 DenseMap<VPPair, unsigned>::iterator K = 758 PairConnectionTypes.find(VPPair(*I, *J)); 759 if (K != PairConnectionTypes.end()) { 760 AllPairConnectionTypes.insert(*K); 761 } else { 762 K = PairConnectionTypes.find(VPPair(*J, *I)); 763 if (K != PairConnectionTypes.end()) 764 AllPairConnectionTypes.insert(*K); 765 } 766 } 767 } 768 769 for (std::multimap<ValuePair, ValuePair>::iterator 770 I = ConnectedPairs.begin(), IE = ConnectedPairs.end(); 771 I != IE; ++I) { 772 if (AllPairConnectionTypes.count(*I)) { 773 AllConnectedPairs.insert(*I); 774 AllConnectedPairDeps.insert(VPPair(I->second, I->first)); 775 } 776 } 777 } while (ShouldContinue); 778 779 if (AllChosenPairs.empty()) return false; 780 NumFusedOps += AllChosenPairs.size(); 781 782 // A set of pairs has now been selected. It is now necessary to replace the 783 // paired instructions with vector instructions. For this procedure each 784 // operand must be replaced with a vector operand. This vector is formed 785 // by using build_vector on the old operands. The replaced values are then 786 // replaced with a vector_extract on the result. Subsequent optimization 787 // passes should coalesce the build/extract combinations. 788 789 fuseChosenPairs(BB, AllPairableInsts, AllChosenPairs, AllFixedOrderPairs, 790 AllPairConnectionTypes, 791 AllConnectedPairs, AllConnectedPairDeps); 792 793 // It is important to cleanup here so that future iterations of this 794 // function have less work to do. 795 (void) SimplifyInstructionsInBlock(&BB, TD, AA->getTargetLibraryInfo()); 796 return true; 797 } 798 799 // This function returns true if the provided instruction is capable of being 800 // fused into a vector instruction. This determination is based only on the 801 // type and other attributes of the instruction. 802 bool BBVectorize::isInstVectorizable(Instruction *I, 803 bool &IsSimpleLoadStore) { 804 IsSimpleLoadStore = false; 805 806 if (CallInst *C = dyn_cast<CallInst>(I)) { 807 if (!isVectorizableIntrinsic(C)) 808 return false; 809 } else if (LoadInst *L = dyn_cast<LoadInst>(I)) { 810 // Vectorize simple loads if possbile: 811 IsSimpleLoadStore = L->isSimple(); 812 if (!IsSimpleLoadStore || !Config.VectorizeMemOps) 813 return false; 814 } else if (StoreInst *S = dyn_cast<StoreInst>(I)) { 815 // Vectorize simple stores if possbile: 816 IsSimpleLoadStore = S->isSimple(); 817 if (!IsSimpleLoadStore || !Config.VectorizeMemOps) 818 return false; 819 } else if (CastInst *C = dyn_cast<CastInst>(I)) { 820 // We can vectorize casts, but not casts of pointer types, etc. 821 if (!Config.VectorizeCasts) 822 return false; 823 824 Type *SrcTy = C->getSrcTy(); 825 if (!SrcTy->isSingleValueType()) 826 return false; 827 828 Type *DestTy = C->getDestTy(); 829 if (!DestTy->isSingleValueType()) 830 return false; 831 } else if (isa<SelectInst>(I)) { 832 if (!Config.VectorizeSelect) 833 return false; 834 } else if (isa<CmpInst>(I)) { 835 if (!Config.VectorizeCmp) 836 return false; 837 } else if (GetElementPtrInst *G = dyn_cast<GetElementPtrInst>(I)) { 838 if (!Config.VectorizeGEP) 839 return false; 840 841 // Currently, vector GEPs exist only with one index. 842 if (G->getNumIndices() != 1) 843 return false; 844 } else if (!(I->isBinaryOp() || isa<ShuffleVectorInst>(I) || 845 isa<ExtractElementInst>(I) || isa<InsertElementInst>(I))) { 846 return false; 847 } 848 849 // We can't vectorize memory operations without target data 850 if (TD == 0 && IsSimpleLoadStore) 851 return false; 852 853 Type *T1, *T2; 854 getInstructionTypes(I, T1, T2); 855 856 // Not every type can be vectorized... 857 if (!(VectorType::isValidElementType(T1) || T1->isVectorTy()) || 858 !(VectorType::isValidElementType(T2) || T2->isVectorTy())) 859 return false; 860 861 if (T1->getScalarSizeInBits() == 1) { 862 if (!Config.VectorizeBools) 863 return false; 864 } else { 865 if (!Config.VectorizeInts && T1->isIntOrIntVectorTy()) 866 return false; 867 } 868 869 if (T2->getScalarSizeInBits() == 1) { 870 if (!Config.VectorizeBools) 871 return false; 872 } else { 873 if (!Config.VectorizeInts && T2->isIntOrIntVectorTy()) 874 return false; 875 } 876 877 if (!Config.VectorizeFloats 878 && (T1->isFPOrFPVectorTy() || T2->isFPOrFPVectorTy())) 879 return false; 880 881 // Don't vectorize target-specific types. 882 if (T1->isX86_FP80Ty() || T1->isPPC_FP128Ty() || T1->isX86_MMXTy()) 883 return false; 884 if (T2->isX86_FP80Ty() || T2->isPPC_FP128Ty() || T2->isX86_MMXTy()) 885 return false; 886 887 if ((!Config.VectorizePointers || TD == 0) && 888 (T1->getScalarType()->isPointerTy() || 889 T2->getScalarType()->isPointerTy())) 890 return false; 891 892 if (!VTTI && (T1->getPrimitiveSizeInBits() >= Config.VectorBits || 893 T2->getPrimitiveSizeInBits() >= Config.VectorBits)) 894 return false; 895 896 return true; 897 } 898 899 // This function returns true if the two provided instructions are compatible 900 // (meaning that they can be fused into a vector instruction). This assumes 901 // that I has already been determined to be vectorizable and that J is not 902 // in the use tree of I. 903 bool BBVectorize::areInstsCompatible(Instruction *I, Instruction *J, 904 bool IsSimpleLoadStore, bool NonPow2Len, 905 int &CostSavings, int &FixedOrder) { 906 DEBUG(if (DebugInstructionExamination) dbgs() << "BBV: looking at " << *I << 907 " <-> " << *J << "\n"); 908 909 CostSavings = 0; 910 FixedOrder = 0; 911 912 // Loads and stores can be merged if they have different alignments, 913 // but are otherwise the same. 914 if (!J->isSameOperationAs(I, Instruction::CompareIgnoringAlignment | 915 (NonPow2Len ? Instruction::CompareUsingScalarTypes : 0))) 916 return false; 917 918 Type *IT1, *IT2, *JT1, *JT2; 919 getInstructionTypes(I, IT1, IT2); 920 getInstructionTypes(J, JT1, JT2); 921 unsigned MaxTypeBits = std::max( 922 IT1->getPrimitiveSizeInBits() + JT1->getPrimitiveSizeInBits(), 923 IT2->getPrimitiveSizeInBits() + JT2->getPrimitiveSizeInBits()); 924 if (!VTTI && MaxTypeBits > Config.VectorBits) 925 return false; 926 927 // FIXME: handle addsub-type operations! 928 929 if (IsSimpleLoadStore) { 930 Value *IPtr, *JPtr; 931 unsigned IAlignment, JAlignment, IAddressSpace, JAddressSpace; 932 int64_t OffsetInElmts = 0; 933 if (getPairPtrInfo(I, J, IPtr, JPtr, IAlignment, JAlignment, 934 IAddressSpace, JAddressSpace, 935 OffsetInElmts) && abs64(OffsetInElmts) == 1) { 936 FixedOrder = (int) OffsetInElmts; 937 unsigned BottomAlignment = IAlignment; 938 if (OffsetInElmts < 0) BottomAlignment = JAlignment; 939 940 Type *aTypeI = isa<StoreInst>(I) ? 941 cast<StoreInst>(I)->getValueOperand()->getType() : I->getType(); 942 Type *aTypeJ = isa<StoreInst>(J) ? 943 cast<StoreInst>(J)->getValueOperand()->getType() : J->getType(); 944 Type *VType = getVecTypeForPair(aTypeI, aTypeJ); 945 946 if (Config.AlignedOnly) { 947 // An aligned load or store is possible only if the instruction 948 // with the lower offset has an alignment suitable for the 949 // vector type. 950 951 unsigned VecAlignment = TD->getPrefTypeAlignment(VType); 952 if (BottomAlignment < VecAlignment) 953 return false; 954 } 955 956 if (VTTI) { 957 unsigned ICost = VTTI->getMemoryOpCost(I->getOpcode(), I->getType(), 958 IAlignment, IAddressSpace); 959 unsigned JCost = VTTI->getMemoryOpCost(J->getOpcode(), J->getType(), 960 JAlignment, JAddressSpace); 961 unsigned VCost = VTTI->getMemoryOpCost(I->getOpcode(), VType, 962 BottomAlignment, 963 IAddressSpace); 964 if (VCost > ICost + JCost) 965 return false; 966 967 // We don't want to fuse to a type that will be split, even 968 // if the two input types will also be split and there is no other 969 // associated cost. 970 unsigned VParts = VTTI->getNumberOfParts(VType); 971 if (VParts > 1) 972 return false; 973 else if (!VParts && VCost == ICost + JCost) 974 return false; 975 976 CostSavings = ICost + JCost - VCost; 977 } 978 } else { 979 return false; 980 } 981 } else if (VTTI) { 982 unsigned ICost = getInstrCost(I->getOpcode(), IT1, IT2); 983 unsigned JCost = getInstrCost(J->getOpcode(), JT1, JT2); 984 Type *VT1 = getVecTypeForPair(IT1, JT1), 985 *VT2 = getVecTypeForPair(IT2, JT2); 986 unsigned VCost = getInstrCost(I->getOpcode(), VT1, VT2); 987 988 if (VCost > ICost + JCost) 989 return false; 990 991 // We don't want to fuse to a type that will be split, even 992 // if the two input types will also be split and there is no other 993 // associated cost. 994 unsigned VParts1 = VTTI->getNumberOfParts(VT1), 995 VParts2 = VTTI->getNumberOfParts(VT2); 996 if (VParts1 > 1 || VParts2 > 1) 997 return false; 998 else if ((!VParts1 || !VParts2) && VCost == ICost + JCost) 999 return false; 1000 1001 CostSavings = ICost + JCost - VCost; 1002 } 1003 1004 // The powi intrinsic is special because only the first argument is 1005 // vectorized, the second arguments must be equal. 1006 CallInst *CI = dyn_cast<CallInst>(I); 1007 Function *FI; 1008 if (CI && (FI = CI->getCalledFunction()) && 1009 FI->getIntrinsicID() == Intrinsic::powi) { 1010 1011 Value *A1I = CI->getArgOperand(1), 1012 *A1J = cast<CallInst>(J)->getArgOperand(1); 1013 const SCEV *A1ISCEV = SE->getSCEV(A1I), 1014 *A1JSCEV = SE->getSCEV(A1J); 1015 return (A1ISCEV == A1JSCEV); 1016 } 1017 1018 return true; 1019 } 1020 1021 // Figure out whether or not J uses I and update the users and write-set 1022 // structures associated with I. Specifically, Users represents the set of 1023 // instructions that depend on I. WriteSet represents the set 1024 // of memory locations that are dependent on I. If UpdateUsers is true, 1025 // and J uses I, then Users is updated to contain J and WriteSet is updated 1026 // to contain any memory locations to which J writes. The function returns 1027 // true if J uses I. By default, alias analysis is used to determine 1028 // whether J reads from memory that overlaps with a location in WriteSet. 1029 // If LoadMoveSet is not null, then it is a previously-computed multimap 1030 // where the key is the memory-based user instruction and the value is 1031 // the instruction to be compared with I. So, if LoadMoveSet is provided, 1032 // then the alias analysis is not used. This is necessary because this 1033 // function is called during the process of moving instructions during 1034 // vectorization and the results of the alias analysis are not stable during 1035 // that process. 1036 bool BBVectorize::trackUsesOfI(DenseSet<Value *> &Users, 1037 AliasSetTracker &WriteSet, Instruction *I, 1038 Instruction *J, bool UpdateUsers, 1039 std::multimap<Value *, Value *> *LoadMoveSet) { 1040 bool UsesI = false; 1041 1042 // This instruction may already be marked as a user due, for example, to 1043 // being a member of a selected pair. 1044 if (Users.count(J)) 1045 UsesI = true; 1046 1047 if (!UsesI) 1048 for (User::op_iterator JU = J->op_begin(), JE = J->op_end(); 1049 JU != JE; ++JU) { 1050 Value *V = *JU; 1051 if (I == V || Users.count(V)) { 1052 UsesI = true; 1053 break; 1054 } 1055 } 1056 if (!UsesI && J->mayReadFromMemory()) { 1057 if (LoadMoveSet) { 1058 VPIteratorPair JPairRange = LoadMoveSet->equal_range(J); 1059 UsesI = isSecondInIteratorPair<Value*>(I, JPairRange); 1060 } else { 1061 for (AliasSetTracker::iterator W = WriteSet.begin(), 1062 WE = WriteSet.end(); W != WE; ++W) { 1063 if (W->aliasesUnknownInst(J, *AA)) { 1064 UsesI = true; 1065 break; 1066 } 1067 } 1068 } 1069 } 1070 1071 if (UsesI && UpdateUsers) { 1072 if (J->mayWriteToMemory()) WriteSet.add(J); 1073 Users.insert(J); 1074 } 1075 1076 return UsesI; 1077 } 1078 1079 // This function iterates over all instruction pairs in the provided 1080 // basic block and collects all candidate pairs for vectorization. 1081 bool BBVectorize::getCandidatePairs(BasicBlock &BB, 1082 BasicBlock::iterator &Start, 1083 std::multimap<Value *, Value *> &CandidatePairs, 1084 DenseSet<ValuePair> &FixedOrderPairs, 1085 DenseMap<ValuePair, int> &CandidatePairCostSavings, 1086 std::vector<Value *> &PairableInsts, bool NonPow2Len) { 1087 BasicBlock::iterator E = BB.end(); 1088 if (Start == E) return false; 1089 1090 bool ShouldContinue = false, IAfterStart = false; 1091 for (BasicBlock::iterator I = Start++; I != E; ++I) { 1092 if (I == Start) IAfterStart = true; 1093 1094 bool IsSimpleLoadStore; 1095 if (!isInstVectorizable(I, IsSimpleLoadStore)) continue; 1096 1097 // Look for an instruction with which to pair instruction *I... 1098 DenseSet<Value *> Users; 1099 AliasSetTracker WriteSet(*AA); 1100 bool JAfterStart = IAfterStart; 1101 BasicBlock::iterator J = llvm::next(I); 1102 for (unsigned ss = 0; J != E && ss <= Config.SearchLimit; ++J, ++ss) { 1103 if (J == Start) JAfterStart = true; 1104 1105 // Determine if J uses I, if so, exit the loop. 1106 bool UsesI = trackUsesOfI(Users, WriteSet, I, J, !Config.FastDep); 1107 if (Config.FastDep) { 1108 // Note: For this heuristic to be effective, independent operations 1109 // must tend to be intermixed. This is likely to be true from some 1110 // kinds of grouped loop unrolling (but not the generic LLVM pass), 1111 // but otherwise may require some kind of reordering pass. 1112 1113 // When using fast dependency analysis, 1114 // stop searching after first use: 1115 if (UsesI) break; 1116 } else { 1117 if (UsesI) continue; 1118 } 1119 1120 // J does not use I, and comes before the first use of I, so it can be 1121 // merged with I if the instructions are compatible. 1122 int CostSavings, FixedOrder; 1123 if (!areInstsCompatible(I, J, IsSimpleLoadStore, NonPow2Len, 1124 CostSavings, FixedOrder)) continue; 1125 1126 // J is a candidate for merging with I. 1127 if (!PairableInsts.size() || 1128 PairableInsts[PairableInsts.size()-1] != I) { 1129 PairableInsts.push_back(I); 1130 } 1131 1132 CandidatePairs.insert(ValuePair(I, J)); 1133 if (VTTI) 1134 CandidatePairCostSavings.insert(ValuePairWithCost(ValuePair(I, J), 1135 CostSavings)); 1136 1137 if (FixedOrder == 1) 1138 FixedOrderPairs.insert(ValuePair(I, J)); 1139 else if (FixedOrder == -1) 1140 FixedOrderPairs.insert(ValuePair(J, I)); 1141 1142 // The next call to this function must start after the last instruction 1143 // selected during this invocation. 1144 if (JAfterStart) { 1145 Start = llvm::next(J); 1146 IAfterStart = JAfterStart = false; 1147 } 1148 1149 DEBUG(if (DebugCandidateSelection) dbgs() << "BBV: candidate pair " 1150 << *I << " <-> " << *J << " (cost savings: " << 1151 CostSavings << ")\n"); 1152 1153 // If we have already found too many pairs, break here and this function 1154 // will be called again starting after the last instruction selected 1155 // during this invocation. 1156 if (PairableInsts.size() >= Config.MaxInsts) { 1157 ShouldContinue = true; 1158 break; 1159 } 1160 } 1161 1162 if (ShouldContinue) 1163 break; 1164 } 1165 1166 DEBUG(dbgs() << "BBV: found " << PairableInsts.size() 1167 << " instructions with candidate pairs\n"); 1168 1169 return ShouldContinue; 1170 } 1171 1172 // Finds candidate pairs connected to the pair P = <PI, PJ>. This means that 1173 // it looks for pairs such that both members have an input which is an 1174 // output of PI or PJ. 1175 void BBVectorize::computePairsConnectedTo( 1176 std::multimap<Value *, Value *> &CandidatePairs, 1177 std::vector<Value *> &PairableInsts, 1178 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 1179 DenseMap<VPPair, unsigned> &PairConnectionTypes, 1180 ValuePair P) { 1181 StoreInst *SI, *SJ; 1182 1183 // For each possible pairing for this variable, look at the uses of 1184 // the first value... 1185 for (Value::use_iterator I = P.first->use_begin(), 1186 E = P.first->use_end(); I != E; ++I) { 1187 if (isa<LoadInst>(*I)) { 1188 // A pair cannot be connected to a load because the load only takes one 1189 // operand (the address) and it is a scalar even after vectorization. 1190 continue; 1191 } else if ((SI = dyn_cast<StoreInst>(*I)) && 1192 P.first == SI->getPointerOperand()) { 1193 // Similarly, a pair cannot be connected to a store through its 1194 // pointer operand. 1195 continue; 1196 } 1197 1198 VPIteratorPair IPairRange = CandidatePairs.equal_range(*I); 1199 1200 // For each use of the first variable, look for uses of the second 1201 // variable... 1202 for (Value::use_iterator J = P.second->use_begin(), 1203 E2 = P.second->use_end(); J != E2; ++J) { 1204 if ((SJ = dyn_cast<StoreInst>(*J)) && 1205 P.second == SJ->getPointerOperand()) 1206 continue; 1207 1208 VPIteratorPair JPairRange = CandidatePairs.equal_range(*J); 1209 1210 // Look for <I, J>: 1211 if (isSecondInIteratorPair<Value*>(*J, IPairRange)) { 1212 VPPair VP(P, ValuePair(*I, *J)); 1213 ConnectedPairs.insert(VP); 1214 PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionDirect)); 1215 } 1216 1217 // Look for <J, I>: 1218 if (isSecondInIteratorPair<Value*>(*I, JPairRange)) { 1219 VPPair VP(P, ValuePair(*J, *I)); 1220 ConnectedPairs.insert(VP); 1221 PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionSwap)); 1222 } 1223 } 1224 1225 if (Config.SplatBreaksChain) continue; 1226 // Look for cases where just the first value in the pair is used by 1227 // both members of another pair (splatting). 1228 for (Value::use_iterator J = P.first->use_begin(); J != E; ++J) { 1229 if ((SJ = dyn_cast<StoreInst>(*J)) && 1230 P.first == SJ->getPointerOperand()) 1231 continue; 1232 1233 if (isSecondInIteratorPair<Value*>(*J, IPairRange)) { 1234 VPPair VP(P, ValuePair(*I, *J)); 1235 ConnectedPairs.insert(VP); 1236 PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionSplat)); 1237 } 1238 } 1239 } 1240 1241 if (Config.SplatBreaksChain) return; 1242 // Look for cases where just the second value in the pair is used by 1243 // both members of another pair (splatting). 1244 for (Value::use_iterator I = P.second->use_begin(), 1245 E = P.second->use_end(); I != E; ++I) { 1246 if (isa<LoadInst>(*I)) 1247 continue; 1248 else if ((SI = dyn_cast<StoreInst>(*I)) && 1249 P.second == SI->getPointerOperand()) 1250 continue; 1251 1252 VPIteratorPair IPairRange = CandidatePairs.equal_range(*I); 1253 1254 for (Value::use_iterator J = P.second->use_begin(); J != E; ++J) { 1255 if ((SJ = dyn_cast<StoreInst>(*J)) && 1256 P.second == SJ->getPointerOperand()) 1257 continue; 1258 1259 if (isSecondInIteratorPair<Value*>(*J, IPairRange)) { 1260 VPPair VP(P, ValuePair(*I, *J)); 1261 ConnectedPairs.insert(VP); 1262 PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionSplat)); 1263 } 1264 } 1265 } 1266 } 1267 1268 // This function figures out which pairs are connected. Two pairs are 1269 // connected if some output of the first pair forms an input to both members 1270 // of the second pair. 1271 void BBVectorize::computeConnectedPairs( 1272 std::multimap<Value *, Value *> &CandidatePairs, 1273 std::vector<Value *> &PairableInsts, 1274 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 1275 DenseMap<VPPair, unsigned> &PairConnectionTypes) { 1276 1277 for (std::vector<Value *>::iterator PI = PairableInsts.begin(), 1278 PE = PairableInsts.end(); PI != PE; ++PI) { 1279 VPIteratorPair choiceRange = CandidatePairs.equal_range(*PI); 1280 1281 for (std::multimap<Value *, Value *>::iterator P = choiceRange.first; 1282 P != choiceRange.second; ++P) 1283 computePairsConnectedTo(CandidatePairs, PairableInsts, 1284 ConnectedPairs, PairConnectionTypes, *P); 1285 } 1286 1287 DEBUG(dbgs() << "BBV: found " << ConnectedPairs.size() 1288 << " pair connections.\n"); 1289 } 1290 1291 // This function builds a set of use tuples such that <A, B> is in the set 1292 // if B is in the use tree of A. If B is in the use tree of A, then B 1293 // depends on the output of A. 1294 void BBVectorize::buildDepMap( 1295 BasicBlock &BB, 1296 std::multimap<Value *, Value *> &CandidatePairs, 1297 std::vector<Value *> &PairableInsts, 1298 DenseSet<ValuePair> &PairableInstUsers) { 1299 DenseSet<Value *> IsInPair; 1300 for (std::multimap<Value *, Value *>::iterator C = CandidatePairs.begin(), 1301 E = CandidatePairs.end(); C != E; ++C) { 1302 IsInPair.insert(C->first); 1303 IsInPair.insert(C->second); 1304 } 1305 1306 // Iterate through the basic block, recording all Users of each 1307 // pairable instruction. 1308 1309 BasicBlock::iterator E = BB.end(); 1310 for (BasicBlock::iterator I = BB.getFirstInsertionPt(); I != E; ++I) { 1311 if (IsInPair.find(I) == IsInPair.end()) continue; 1312 1313 DenseSet<Value *> Users; 1314 AliasSetTracker WriteSet(*AA); 1315 for (BasicBlock::iterator J = llvm::next(I); J != E; ++J) 1316 (void) trackUsesOfI(Users, WriteSet, I, J); 1317 1318 for (DenseSet<Value *>::iterator U = Users.begin(), E = Users.end(); 1319 U != E; ++U) 1320 PairableInstUsers.insert(ValuePair(I, *U)); 1321 } 1322 } 1323 1324 // Returns true if an input to pair P is an output of pair Q and also an 1325 // input of pair Q is an output of pair P. If this is the case, then these 1326 // two pairs cannot be simultaneously fused. 1327 bool BBVectorize::pairsConflict(ValuePair P, ValuePair Q, 1328 DenseSet<ValuePair> &PairableInstUsers, 1329 std::multimap<ValuePair, ValuePair> *PairableInstUserMap) { 1330 // Two pairs are in conflict if they are mutual Users of eachother. 1331 bool QUsesP = PairableInstUsers.count(ValuePair(P.first, Q.first)) || 1332 PairableInstUsers.count(ValuePair(P.first, Q.second)) || 1333 PairableInstUsers.count(ValuePair(P.second, Q.first)) || 1334 PairableInstUsers.count(ValuePair(P.second, Q.second)); 1335 bool PUsesQ = PairableInstUsers.count(ValuePair(Q.first, P.first)) || 1336 PairableInstUsers.count(ValuePair(Q.first, P.second)) || 1337 PairableInstUsers.count(ValuePair(Q.second, P.first)) || 1338 PairableInstUsers.count(ValuePair(Q.second, P.second)); 1339 if (PairableInstUserMap) { 1340 // FIXME: The expensive part of the cycle check is not so much the cycle 1341 // check itself but this edge insertion procedure. This needs some 1342 // profiling and probably a different data structure (same is true of 1343 // most uses of std::multimap). 1344 if (PUsesQ) { 1345 VPPIteratorPair QPairRange = PairableInstUserMap->equal_range(Q); 1346 if (!isSecondInIteratorPair(P, QPairRange)) 1347 PairableInstUserMap->insert(VPPair(Q, P)); 1348 } 1349 if (QUsesP) { 1350 VPPIteratorPair PPairRange = PairableInstUserMap->equal_range(P); 1351 if (!isSecondInIteratorPair(Q, PPairRange)) 1352 PairableInstUserMap->insert(VPPair(P, Q)); 1353 } 1354 } 1355 1356 return (QUsesP && PUsesQ); 1357 } 1358 1359 // This function walks the use graph of current pairs to see if, starting 1360 // from P, the walk returns to P. 1361 bool BBVectorize::pairWillFormCycle(ValuePair P, 1362 std::multimap<ValuePair, ValuePair> &PairableInstUserMap, 1363 DenseSet<ValuePair> &CurrentPairs) { 1364 DEBUG(if (DebugCycleCheck) 1365 dbgs() << "BBV: starting cycle check for : " << *P.first << " <-> " 1366 << *P.second << "\n"); 1367 // A lookup table of visisted pairs is kept because the PairableInstUserMap 1368 // contains non-direct associations. 1369 DenseSet<ValuePair> Visited; 1370 SmallVector<ValuePair, 32> Q; 1371 // General depth-first post-order traversal: 1372 Q.push_back(P); 1373 do { 1374 ValuePair QTop = Q.pop_back_val(); 1375 Visited.insert(QTop); 1376 1377 DEBUG(if (DebugCycleCheck) 1378 dbgs() << "BBV: cycle check visiting: " << *QTop.first << " <-> " 1379 << *QTop.second << "\n"); 1380 VPPIteratorPair QPairRange = PairableInstUserMap.equal_range(QTop); 1381 for (std::multimap<ValuePair, ValuePair>::iterator C = QPairRange.first; 1382 C != QPairRange.second; ++C) { 1383 if (C->second == P) { 1384 DEBUG(dbgs() 1385 << "BBV: rejected to prevent non-trivial cycle formation: " 1386 << *C->first.first << " <-> " << *C->first.second << "\n"); 1387 return true; 1388 } 1389 1390 if (CurrentPairs.count(C->second) && !Visited.count(C->second)) 1391 Q.push_back(C->second); 1392 } 1393 } while (!Q.empty()); 1394 1395 return false; 1396 } 1397 1398 // This function builds the initial tree of connected pairs with the 1399 // pair J at the root. 1400 void BBVectorize::buildInitialTreeFor( 1401 std::multimap<Value *, Value *> &CandidatePairs, 1402 std::vector<Value *> &PairableInsts, 1403 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 1404 DenseSet<ValuePair> &PairableInstUsers, 1405 DenseMap<Value *, Value *> &ChosenPairs, 1406 DenseMap<ValuePair, size_t> &Tree, ValuePair J) { 1407 // Each of these pairs is viewed as the root node of a Tree. The Tree 1408 // is then walked (depth-first). As this happens, we keep track of 1409 // the pairs that compose the Tree and the maximum depth of the Tree. 1410 SmallVector<ValuePairWithDepth, 32> Q; 1411 // General depth-first post-order traversal: 1412 Q.push_back(ValuePairWithDepth(J, getDepthFactor(J.first))); 1413 do { 1414 ValuePairWithDepth QTop = Q.back(); 1415 1416 // Push each child onto the queue: 1417 bool MoreChildren = false; 1418 size_t MaxChildDepth = QTop.second; 1419 VPPIteratorPair qtRange = ConnectedPairs.equal_range(QTop.first); 1420 for (std::multimap<ValuePair, ValuePair>::iterator k = qtRange.first; 1421 k != qtRange.second; ++k) { 1422 // Make sure that this child pair is still a candidate: 1423 bool IsStillCand = false; 1424 VPIteratorPair checkRange = 1425 CandidatePairs.equal_range(k->second.first); 1426 for (std::multimap<Value *, Value *>::iterator m = checkRange.first; 1427 m != checkRange.second; ++m) { 1428 if (m->second == k->second.second) { 1429 IsStillCand = true; 1430 break; 1431 } 1432 } 1433 1434 if (IsStillCand) { 1435 DenseMap<ValuePair, size_t>::iterator C = Tree.find(k->second); 1436 if (C == Tree.end()) { 1437 size_t d = getDepthFactor(k->second.first); 1438 Q.push_back(ValuePairWithDepth(k->second, QTop.second+d)); 1439 MoreChildren = true; 1440 } else { 1441 MaxChildDepth = std::max(MaxChildDepth, C->second); 1442 } 1443 } 1444 } 1445 1446 if (!MoreChildren) { 1447 // Record the current pair as part of the Tree: 1448 Tree.insert(ValuePairWithDepth(QTop.first, MaxChildDepth)); 1449 Q.pop_back(); 1450 } 1451 } while (!Q.empty()); 1452 } 1453 1454 // Given some initial tree, prune it by removing conflicting pairs (pairs 1455 // that cannot be simultaneously chosen for vectorization). 1456 void BBVectorize::pruneTreeFor( 1457 std::multimap<Value *, Value *> &CandidatePairs, 1458 std::vector<Value *> &PairableInsts, 1459 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 1460 DenseSet<ValuePair> &PairableInstUsers, 1461 std::multimap<ValuePair, ValuePair> &PairableInstUserMap, 1462 DenseMap<Value *, Value *> &ChosenPairs, 1463 DenseMap<ValuePair, size_t> &Tree, 1464 DenseSet<ValuePair> &PrunedTree, ValuePair J, 1465 bool UseCycleCheck) { 1466 SmallVector<ValuePairWithDepth, 32> Q; 1467 // General depth-first post-order traversal: 1468 Q.push_back(ValuePairWithDepth(J, getDepthFactor(J.first))); 1469 do { 1470 ValuePairWithDepth QTop = Q.pop_back_val(); 1471 PrunedTree.insert(QTop.first); 1472 1473 // Visit each child, pruning as necessary... 1474 DenseMap<ValuePair, size_t> BestChildren; 1475 VPPIteratorPair QTopRange = ConnectedPairs.equal_range(QTop.first); 1476 for (std::multimap<ValuePair, ValuePair>::iterator K = QTopRange.first; 1477 K != QTopRange.second; ++K) { 1478 DenseMap<ValuePair, size_t>::iterator C = Tree.find(K->second); 1479 if (C == Tree.end()) continue; 1480 1481 // This child is in the Tree, now we need to make sure it is the 1482 // best of any conflicting children. There could be multiple 1483 // conflicting children, so first, determine if we're keeping 1484 // this child, then delete conflicting children as necessary. 1485 1486 // It is also necessary to guard against pairing-induced 1487 // dependencies. Consider instructions a .. x .. y .. b 1488 // such that (a,b) are to be fused and (x,y) are to be fused 1489 // but a is an input to x and b is an output from y. This 1490 // means that y cannot be moved after b but x must be moved 1491 // after b for (a,b) to be fused. In other words, after 1492 // fusing (a,b) we have y .. a/b .. x where y is an input 1493 // to a/b and x is an output to a/b: x and y can no longer 1494 // be legally fused. To prevent this condition, we must 1495 // make sure that a child pair added to the Tree is not 1496 // both an input and output of an already-selected pair. 1497 1498 // Pairing-induced dependencies can also form from more complicated 1499 // cycles. The pair vs. pair conflicts are easy to check, and so 1500 // that is done explicitly for "fast rejection", and because for 1501 // child vs. child conflicts, we may prefer to keep the current 1502 // pair in preference to the already-selected child. 1503 DenseSet<ValuePair> CurrentPairs; 1504 1505 bool CanAdd = true; 1506 for (DenseMap<ValuePair, size_t>::iterator C2 1507 = BestChildren.begin(), E2 = BestChildren.end(); 1508 C2 != E2; ++C2) { 1509 if (C2->first.first == C->first.first || 1510 C2->first.first == C->first.second || 1511 C2->first.second == C->first.first || 1512 C2->first.second == C->first.second || 1513 pairsConflict(C2->first, C->first, PairableInstUsers, 1514 UseCycleCheck ? &PairableInstUserMap : 0)) { 1515 if (C2->second >= C->second) { 1516 CanAdd = false; 1517 break; 1518 } 1519 1520 CurrentPairs.insert(C2->first); 1521 } 1522 } 1523 if (!CanAdd) continue; 1524 1525 // Even worse, this child could conflict with another node already 1526 // selected for the Tree. If that is the case, ignore this child. 1527 for (DenseSet<ValuePair>::iterator T = PrunedTree.begin(), 1528 E2 = PrunedTree.end(); T != E2; ++T) { 1529 if (T->first == C->first.first || 1530 T->first == C->first.second || 1531 T->second == C->first.first || 1532 T->second == C->first.second || 1533 pairsConflict(*T, C->first, PairableInstUsers, 1534 UseCycleCheck ? &PairableInstUserMap : 0)) { 1535 CanAdd = false; 1536 break; 1537 } 1538 1539 CurrentPairs.insert(*T); 1540 } 1541 if (!CanAdd) continue; 1542 1543 // And check the queue too... 1544 for (SmallVector<ValuePairWithDepth, 32>::iterator C2 = Q.begin(), 1545 E2 = Q.end(); C2 != E2; ++C2) { 1546 if (C2->first.first == C->first.first || 1547 C2->first.first == C->first.second || 1548 C2->first.second == C->first.first || 1549 C2->first.second == C->first.second || 1550 pairsConflict(C2->first, C->first, PairableInstUsers, 1551 UseCycleCheck ? &PairableInstUserMap : 0)) { 1552 CanAdd = false; 1553 break; 1554 } 1555 1556 CurrentPairs.insert(C2->first); 1557 } 1558 if (!CanAdd) continue; 1559 1560 // Last but not least, check for a conflict with any of the 1561 // already-chosen pairs. 1562 for (DenseMap<Value *, Value *>::iterator C2 = 1563 ChosenPairs.begin(), E2 = ChosenPairs.end(); 1564 C2 != E2; ++C2) { 1565 if (pairsConflict(*C2, C->first, PairableInstUsers, 1566 UseCycleCheck ? &PairableInstUserMap : 0)) { 1567 CanAdd = false; 1568 break; 1569 } 1570 1571 CurrentPairs.insert(*C2); 1572 } 1573 if (!CanAdd) continue; 1574 1575 // To check for non-trivial cycles formed by the addition of the 1576 // current pair we've formed a list of all relevant pairs, now use a 1577 // graph walk to check for a cycle. We start from the current pair and 1578 // walk the use tree to see if we again reach the current pair. If we 1579 // do, then the current pair is rejected. 1580 1581 // FIXME: It may be more efficient to use a topological-ordering 1582 // algorithm to improve the cycle check. This should be investigated. 1583 if (UseCycleCheck && 1584 pairWillFormCycle(C->first, PairableInstUserMap, CurrentPairs)) 1585 continue; 1586 1587 // This child can be added, but we may have chosen it in preference 1588 // to an already-selected child. Check for this here, and if a 1589 // conflict is found, then remove the previously-selected child 1590 // before adding this one in its place. 1591 for (DenseMap<ValuePair, size_t>::iterator C2 1592 = BestChildren.begin(); C2 != BestChildren.end();) { 1593 if (C2->first.first == C->first.first || 1594 C2->first.first == C->first.second || 1595 C2->first.second == C->first.first || 1596 C2->first.second == C->first.second || 1597 pairsConflict(C2->first, C->first, PairableInstUsers)) 1598 BestChildren.erase(C2++); 1599 else 1600 ++C2; 1601 } 1602 1603 BestChildren.insert(ValuePairWithDepth(C->first, C->second)); 1604 } 1605 1606 for (DenseMap<ValuePair, size_t>::iterator C 1607 = BestChildren.begin(), E2 = BestChildren.end(); 1608 C != E2; ++C) { 1609 size_t DepthF = getDepthFactor(C->first.first); 1610 Q.push_back(ValuePairWithDepth(C->first, QTop.second+DepthF)); 1611 } 1612 } while (!Q.empty()); 1613 } 1614 1615 // This function finds the best tree of mututally-compatible connected 1616 // pairs, given the choice of root pairs as an iterator range. 1617 void BBVectorize::findBestTreeFor( 1618 std::multimap<Value *, Value *> &CandidatePairs, 1619 DenseMap<ValuePair, int> &CandidatePairCostSavings, 1620 std::vector<Value *> &PairableInsts, 1621 DenseSet<ValuePair> &FixedOrderPairs, 1622 DenseMap<VPPair, unsigned> &PairConnectionTypes, 1623 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 1624 std::multimap<ValuePair, ValuePair> &ConnectedPairDeps, 1625 DenseSet<ValuePair> &PairableInstUsers, 1626 std::multimap<ValuePair, ValuePair> &PairableInstUserMap, 1627 DenseMap<Value *, Value *> &ChosenPairs, 1628 DenseSet<ValuePair> &BestTree, size_t &BestMaxDepth, 1629 int &BestEffSize, VPIteratorPair ChoiceRange, 1630 bool UseCycleCheck) { 1631 for (std::multimap<Value *, Value *>::iterator J = ChoiceRange.first; 1632 J != ChoiceRange.second; ++J) { 1633 1634 // Before going any further, make sure that this pair does not 1635 // conflict with any already-selected pairs (see comment below 1636 // near the Tree pruning for more details). 1637 DenseSet<ValuePair> ChosenPairSet; 1638 bool DoesConflict = false; 1639 for (DenseMap<Value *, Value *>::iterator C = ChosenPairs.begin(), 1640 E = ChosenPairs.end(); C != E; ++C) { 1641 if (pairsConflict(*C, *J, PairableInstUsers, 1642 UseCycleCheck ? &PairableInstUserMap : 0)) { 1643 DoesConflict = true; 1644 break; 1645 } 1646 1647 ChosenPairSet.insert(*C); 1648 } 1649 if (DoesConflict) continue; 1650 1651 if (UseCycleCheck && 1652 pairWillFormCycle(*J, PairableInstUserMap, ChosenPairSet)) 1653 continue; 1654 1655 DenseMap<ValuePair, size_t> Tree; 1656 buildInitialTreeFor(CandidatePairs, PairableInsts, ConnectedPairs, 1657 PairableInstUsers, ChosenPairs, Tree, *J); 1658 1659 // Because we'll keep the child with the largest depth, the largest 1660 // depth is still the same in the unpruned Tree. 1661 size_t MaxDepth = Tree.lookup(*J); 1662 1663 DEBUG(if (DebugPairSelection) dbgs() << "BBV: found Tree for pair {" 1664 << *J->first << " <-> " << *J->second << "} of depth " << 1665 MaxDepth << " and size " << Tree.size() << "\n"); 1666 1667 // At this point the Tree has been constructed, but, may contain 1668 // contradictory children (meaning that different children of 1669 // some tree node may be attempting to fuse the same instruction). 1670 // So now we walk the tree again, in the case of a conflict, 1671 // keep only the child with the largest depth. To break a tie, 1672 // favor the first child. 1673 1674 DenseSet<ValuePair> PrunedTree; 1675 pruneTreeFor(CandidatePairs, PairableInsts, ConnectedPairs, 1676 PairableInstUsers, PairableInstUserMap, ChosenPairs, Tree, 1677 PrunedTree, *J, UseCycleCheck); 1678 1679 int EffSize = 0; 1680 if (VTTI) { 1681 DenseSet<Value *> PrunedTreeInstrs; 1682 for (DenseSet<ValuePair>::iterator S = PrunedTree.begin(), 1683 E = PrunedTree.end(); S != E; ++S) { 1684 PrunedTreeInstrs.insert(S->first); 1685 PrunedTreeInstrs.insert(S->second); 1686 } 1687 1688 // The set of pairs that have already contributed to the total cost. 1689 DenseSet<ValuePair> IncomingPairs; 1690 1691 // The node weights represent the cost savings associated with 1692 // fusing the pair of instructions. 1693 for (DenseSet<ValuePair>::iterator S = PrunedTree.begin(), 1694 E = PrunedTree.end(); S != E; ++S) { 1695 bool FlipOrder = false; 1696 1697 if (getDepthFactor(S->first)) { 1698 int ESContrib = CandidatePairCostSavings.find(*S)->second; 1699 DEBUG(if (DebugPairSelection) dbgs() << "\tweight {" 1700 << *S->first << " <-> " << *S->second << "} = " << 1701 ESContrib << "\n"); 1702 EffSize += ESContrib; 1703 } 1704 1705 // The edge weights contribute in a negative sense: they represent 1706 // the cost of shuffles. 1707 VPPIteratorPair IP = ConnectedPairDeps.equal_range(*S); 1708 if (IP.first != ConnectedPairDeps.end()) { 1709 unsigned NumDepsDirect = 0, NumDepsSwap = 0; 1710 for (std::multimap<ValuePair, ValuePair>::iterator Q = IP.first; 1711 Q != IP.second; ++Q) { 1712 if (!PrunedTree.count(Q->second)) 1713 continue; 1714 DenseMap<VPPair, unsigned>::iterator R = 1715 PairConnectionTypes.find(VPPair(Q->second, Q->first)); 1716 assert(R != PairConnectionTypes.end() && 1717 "Cannot find pair connection type"); 1718 if (R->second == PairConnectionDirect) 1719 ++NumDepsDirect; 1720 else if (R->second == PairConnectionSwap) 1721 ++NumDepsSwap; 1722 } 1723 1724 // If there are more swaps than direct connections, then 1725 // the pair order will be flipped during fusion. So the real 1726 // number of swaps is the minimum number. 1727 FlipOrder = !FixedOrderPairs.count(*S) && 1728 ((NumDepsSwap > NumDepsDirect) || 1729 FixedOrderPairs.count(ValuePair(S->second, S->first))); 1730 1731 for (std::multimap<ValuePair, ValuePair>::iterator Q = IP.first; 1732 Q != IP.second; ++Q) { 1733 if (!PrunedTree.count(Q->second)) 1734 continue; 1735 DenseMap<VPPair, unsigned>::iterator R = 1736 PairConnectionTypes.find(VPPair(Q->second, Q->first)); 1737 assert(R != PairConnectionTypes.end() && 1738 "Cannot find pair connection type"); 1739 Type *Ty1 = Q->second.first->getType(), 1740 *Ty2 = Q->second.second->getType(); 1741 Type *VTy = getVecTypeForPair(Ty1, Ty2); 1742 if ((R->second == PairConnectionDirect && FlipOrder) || 1743 (R->second == PairConnectionSwap && !FlipOrder) || 1744 R->second == PairConnectionSplat) { 1745 int ESContrib = (int) getInstrCost(Instruction::ShuffleVector, 1746 VTy, VTy); 1747 DEBUG(if (DebugPairSelection) dbgs() << "\tcost {" << 1748 *Q->second.first << " <-> " << *Q->second.second << 1749 "} -> {" << 1750 *S->first << " <-> " << *S->second << "} = " << 1751 ESContrib << "\n"); 1752 EffSize -= ESContrib; 1753 } 1754 } 1755 } 1756 1757 // Compute the cost of outgoing edges. We assume that edges outgoing 1758 // to shuffles, inserts or extracts can be merged, and so contribute 1759 // no additional cost. 1760 if (!S->first->getType()->isVoidTy()) { 1761 Type *Ty1 = S->first->getType(), 1762 *Ty2 = S->second->getType(); 1763 Type *VTy = getVecTypeForPair(Ty1, Ty2); 1764 1765 bool NeedsExtraction = false; 1766 for (Value::use_iterator I = S->first->use_begin(), 1767 IE = S->first->use_end(); I != IE; ++I) { 1768 if (isa<ShuffleVectorInst>(*I) || 1769 isa<InsertElementInst>(*I) || 1770 isa<ExtractElementInst>(*I)) 1771 continue; 1772 if (PrunedTreeInstrs.count(*I)) 1773 continue; 1774 NeedsExtraction = true; 1775 break; 1776 } 1777 1778 if (NeedsExtraction) { 1779 int ESContrib; 1780 if (Ty1->isVectorTy()) 1781 ESContrib = (int) getInstrCost(Instruction::ShuffleVector, 1782 Ty1, VTy); 1783 else 1784 ESContrib = (int) VTTI->getVectorInstrCost( 1785 Instruction::ExtractElement, VTy, 0); 1786 1787 DEBUG(if (DebugPairSelection) dbgs() << "\tcost {" << 1788 *S->first << "} = " << ESContrib << "\n"); 1789 EffSize -= ESContrib; 1790 } 1791 1792 NeedsExtraction = false; 1793 for (Value::use_iterator I = S->second->use_begin(), 1794 IE = S->second->use_end(); I != IE; ++I) { 1795 if (isa<ShuffleVectorInst>(*I) || 1796 isa<InsertElementInst>(*I) || 1797 isa<ExtractElementInst>(*I)) 1798 continue; 1799 if (PrunedTreeInstrs.count(*I)) 1800 continue; 1801 NeedsExtraction = true; 1802 break; 1803 } 1804 1805 if (NeedsExtraction) { 1806 int ESContrib; 1807 if (Ty2->isVectorTy()) 1808 ESContrib = (int) getInstrCost(Instruction::ShuffleVector, 1809 Ty2, VTy); 1810 else 1811 ESContrib = (int) VTTI->getVectorInstrCost( 1812 Instruction::ExtractElement, VTy, 1); 1813 DEBUG(if (DebugPairSelection) dbgs() << "\tcost {" << 1814 *S->second << "} = " << ESContrib << "\n"); 1815 EffSize -= ESContrib; 1816 } 1817 } 1818 1819 // Compute the cost of incoming edges. 1820 if (!isa<LoadInst>(S->first) && !isa<StoreInst>(S->first)) { 1821 Instruction *S1 = cast<Instruction>(S->first), 1822 *S2 = cast<Instruction>(S->second); 1823 for (unsigned o = 0; o < S1->getNumOperands(); ++o) { 1824 Value *O1 = S1->getOperand(o), *O2 = S2->getOperand(o); 1825 1826 // Combining constants into vector constants (or small vector 1827 // constants into larger ones are assumed free). 1828 if (isa<Constant>(O1) && isa<Constant>(O2)) 1829 continue; 1830 1831 if (FlipOrder) 1832 std::swap(O1, O2); 1833 1834 ValuePair VP = ValuePair(O1, O2); 1835 ValuePair VPR = ValuePair(O2, O1); 1836 1837 // Internal edges are not handled here. 1838 if (PrunedTree.count(VP) || PrunedTree.count(VPR)) 1839 continue; 1840 1841 Type *Ty1 = O1->getType(), 1842 *Ty2 = O2->getType(); 1843 Type *VTy = getVecTypeForPair(Ty1, Ty2); 1844 1845 // Combining vector operations of the same type is also assumed 1846 // folded with other operations. 1847 if (Ty1 == Ty2 && 1848 (isa<ShuffleVectorInst>(O1) || 1849 isa<InsertElementInst>(O1) || 1850 isa<InsertElementInst>(O1)) && 1851 (isa<ShuffleVectorInst>(O2) || 1852 isa<InsertElementInst>(O2) || 1853 isa<InsertElementInst>(O2))) 1854 continue; 1855 1856 int ESContrib; 1857 // This pair has already been formed. 1858 if (IncomingPairs.count(VP)) { 1859 continue; 1860 } else if (IncomingPairs.count(VPR)) { 1861 ESContrib = (int) getInstrCost(Instruction::ShuffleVector, 1862 VTy, VTy); 1863 } else if (!Ty1->isVectorTy() && !Ty2->isVectorTy()) { 1864 ESContrib = (int) VTTI->getVectorInstrCost( 1865 Instruction::InsertElement, VTy, 0); 1866 ESContrib += (int) VTTI->getVectorInstrCost( 1867 Instruction::InsertElement, VTy, 1); 1868 } else if (!Ty1->isVectorTy()) { 1869 // O1 needs to be inserted into a vector of size O2, and then 1870 // both need to be shuffled together. 1871 ESContrib = (int) VTTI->getVectorInstrCost( 1872 Instruction::InsertElement, Ty2, 0); 1873 ESContrib += (int) getInstrCost(Instruction::ShuffleVector, 1874 VTy, Ty2); 1875 } else if (!Ty2->isVectorTy()) { 1876 // O2 needs to be inserted into a vector of size O1, and then 1877 // both need to be shuffled together. 1878 ESContrib = (int) VTTI->getVectorInstrCost( 1879 Instruction::InsertElement, Ty1, 0); 1880 ESContrib += (int) getInstrCost(Instruction::ShuffleVector, 1881 VTy, Ty1); 1882 } else { 1883 Type *TyBig = Ty1, *TySmall = Ty2; 1884 if (Ty2->getVectorNumElements() > Ty1->getVectorNumElements()) 1885 std::swap(TyBig, TySmall); 1886 1887 ESContrib = (int) getInstrCost(Instruction::ShuffleVector, 1888 VTy, TyBig); 1889 if (TyBig != TySmall) 1890 ESContrib += (int) getInstrCost(Instruction::ShuffleVector, 1891 TyBig, TySmall); 1892 } 1893 1894 DEBUG(if (DebugPairSelection) dbgs() << "\tcost {" 1895 << *O1 << " <-> " << *O2 << "} = " << 1896 ESContrib << "\n"); 1897 EffSize -= ESContrib; 1898 IncomingPairs.insert(VP); 1899 } 1900 } 1901 } 1902 } else { 1903 for (DenseSet<ValuePair>::iterator S = PrunedTree.begin(), 1904 E = PrunedTree.end(); S != E; ++S) 1905 EffSize += (int) getDepthFactor(S->first); 1906 } 1907 1908 DEBUG(if (DebugPairSelection) 1909 dbgs() << "BBV: found pruned Tree for pair {" 1910 << *J->first << " <-> " << *J->second << "} of depth " << 1911 MaxDepth << " and size " << PrunedTree.size() << 1912 " (effective size: " << EffSize << ")\n"); 1913 if (((VTTI && !UseChainDepthWithTI) || 1914 MaxDepth >= Config.ReqChainDepth) && 1915 EffSize > 0 && EffSize > BestEffSize) { 1916 BestMaxDepth = MaxDepth; 1917 BestEffSize = EffSize; 1918 BestTree = PrunedTree; 1919 } 1920 } 1921 } 1922 1923 // Given the list of candidate pairs, this function selects those 1924 // that will be fused into vector instructions. 1925 void BBVectorize::choosePairs( 1926 std::multimap<Value *, Value *> &CandidatePairs, 1927 DenseMap<ValuePair, int> &CandidatePairCostSavings, 1928 std::vector<Value *> &PairableInsts, 1929 DenseSet<ValuePair> &FixedOrderPairs, 1930 DenseMap<VPPair, unsigned> &PairConnectionTypes, 1931 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 1932 std::multimap<ValuePair, ValuePair> &ConnectedPairDeps, 1933 DenseSet<ValuePair> &PairableInstUsers, 1934 DenseMap<Value *, Value *>& ChosenPairs) { 1935 bool UseCycleCheck = 1936 CandidatePairs.size() <= Config.MaxCandPairsForCycleCheck; 1937 std::multimap<ValuePair, ValuePair> PairableInstUserMap; 1938 for (std::vector<Value *>::iterator I = PairableInsts.begin(), 1939 E = PairableInsts.end(); I != E; ++I) { 1940 // The number of possible pairings for this variable: 1941 size_t NumChoices = CandidatePairs.count(*I); 1942 if (!NumChoices) continue; 1943 1944 VPIteratorPair ChoiceRange = CandidatePairs.equal_range(*I); 1945 1946 // The best pair to choose and its tree: 1947 size_t BestMaxDepth = 0; 1948 int BestEffSize = 0; 1949 DenseSet<ValuePair> BestTree; 1950 findBestTreeFor(CandidatePairs, CandidatePairCostSavings, 1951 PairableInsts, FixedOrderPairs, PairConnectionTypes, 1952 ConnectedPairs, ConnectedPairDeps, 1953 PairableInstUsers, PairableInstUserMap, ChosenPairs, 1954 BestTree, BestMaxDepth, BestEffSize, ChoiceRange, 1955 UseCycleCheck); 1956 1957 // A tree has been chosen (or not) at this point. If no tree was 1958 // chosen, then this instruction, I, cannot be paired (and is no longer 1959 // considered). 1960 1961 DEBUG(if (BestTree.size() > 0) 1962 dbgs() << "BBV: selected pairs in the best tree for: " 1963 << *cast<Instruction>(*I) << "\n"); 1964 1965 for (DenseSet<ValuePair>::iterator S = BestTree.begin(), 1966 SE2 = BestTree.end(); S != SE2; ++S) { 1967 // Insert the members of this tree into the list of chosen pairs. 1968 ChosenPairs.insert(ValuePair(S->first, S->second)); 1969 DEBUG(dbgs() << "BBV: selected pair: " << *S->first << " <-> " << 1970 *S->second << "\n"); 1971 1972 // Remove all candidate pairs that have values in the chosen tree. 1973 for (std::multimap<Value *, Value *>::iterator K = 1974 CandidatePairs.begin(); K != CandidatePairs.end();) { 1975 if (K->first == S->first || K->second == S->first || 1976 K->second == S->second || K->first == S->second) { 1977 // Don't remove the actual pair chosen so that it can be used 1978 // in subsequent tree selections. 1979 if (!(K->first == S->first && K->second == S->second)) 1980 CandidatePairs.erase(K++); 1981 else 1982 ++K; 1983 } else { 1984 ++K; 1985 } 1986 } 1987 } 1988 } 1989 1990 DEBUG(dbgs() << "BBV: selected " << ChosenPairs.size() << " pairs.\n"); 1991 } 1992 1993 std::string getReplacementName(Instruction *I, bool IsInput, unsigned o, 1994 unsigned n = 0) { 1995 if (!I->hasName()) 1996 return ""; 1997 1998 return (I->getName() + (IsInput ? ".v.i" : ".v.r") + utostr(o) + 1999 (n > 0 ? "." + utostr(n) : "")).str(); 2000 } 2001 2002 // Returns the value that is to be used as the pointer input to the vector 2003 // instruction that fuses I with J. 2004 Value *BBVectorize::getReplacementPointerInput(LLVMContext& Context, 2005 Instruction *I, Instruction *J, unsigned o) { 2006 Value *IPtr, *JPtr; 2007 unsigned IAlignment, JAlignment, IAddressSpace, JAddressSpace; 2008 int64_t OffsetInElmts; 2009 2010 // Note: the analysis might fail here, that is why the pair order has 2011 // been precomputed (OffsetInElmts must be unused here). 2012 (void) getPairPtrInfo(I, J, IPtr, JPtr, IAlignment, JAlignment, 2013 IAddressSpace, JAddressSpace, 2014 OffsetInElmts, false); 2015 2016 // The pointer value is taken to be the one with the lowest offset. 2017 Value *VPtr = IPtr; 2018 2019 Type *ArgTypeI = cast<PointerType>(IPtr->getType())->getElementType(); 2020 Type *ArgTypeJ = cast<PointerType>(JPtr->getType())->getElementType(); 2021 Type *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ); 2022 Type *VArgPtrType = PointerType::get(VArgType, 2023 cast<PointerType>(IPtr->getType())->getAddressSpace()); 2024 return new BitCastInst(VPtr, VArgPtrType, getReplacementName(I, true, o), 2025 /* insert before */ I); 2026 } 2027 2028 void BBVectorize::fillNewShuffleMask(LLVMContext& Context, Instruction *J, 2029 unsigned MaskOffset, unsigned NumInElem, 2030 unsigned NumInElem1, unsigned IdxOffset, 2031 std::vector<Constant*> &Mask) { 2032 unsigned NumElem1 = cast<VectorType>(J->getType())->getNumElements(); 2033 for (unsigned v = 0; v < NumElem1; ++v) { 2034 int m = cast<ShuffleVectorInst>(J)->getMaskValue(v); 2035 if (m < 0) { 2036 Mask[v+MaskOffset] = UndefValue::get(Type::getInt32Ty(Context)); 2037 } else { 2038 unsigned mm = m + (int) IdxOffset; 2039 if (m >= (int) NumInElem1) 2040 mm += (int) NumInElem; 2041 2042 Mask[v+MaskOffset] = 2043 ConstantInt::get(Type::getInt32Ty(Context), mm); 2044 } 2045 } 2046 } 2047 2048 // Returns the value that is to be used as the vector-shuffle mask to the 2049 // vector instruction that fuses I with J. 2050 Value *BBVectorize::getReplacementShuffleMask(LLVMContext& Context, 2051 Instruction *I, Instruction *J) { 2052 // This is the shuffle mask. We need to append the second 2053 // mask to the first, and the numbers need to be adjusted. 2054 2055 Type *ArgTypeI = I->getType(); 2056 Type *ArgTypeJ = J->getType(); 2057 Type *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ); 2058 2059 unsigned NumElemI = cast<VectorType>(ArgTypeI)->getNumElements(); 2060 2061 // Get the total number of elements in the fused vector type. 2062 // By definition, this must equal the number of elements in 2063 // the final mask. 2064 unsigned NumElem = cast<VectorType>(VArgType)->getNumElements(); 2065 std::vector<Constant*> Mask(NumElem); 2066 2067 Type *OpTypeI = I->getOperand(0)->getType(); 2068 unsigned NumInElemI = cast<VectorType>(OpTypeI)->getNumElements(); 2069 Type *OpTypeJ = J->getOperand(0)->getType(); 2070 unsigned NumInElemJ = cast<VectorType>(OpTypeJ)->getNumElements(); 2071 2072 // The fused vector will be: 2073 // ----------------------------------------------------- 2074 // | NumInElemI | NumInElemJ | NumInElemI | NumInElemJ | 2075 // ----------------------------------------------------- 2076 // from which we'll extract NumElem total elements (where the first NumElemI 2077 // of them come from the mask in I and the remainder come from the mask 2078 // in J. 2079 2080 // For the mask from the first pair... 2081 fillNewShuffleMask(Context, I, 0, NumInElemJ, NumInElemI, 2082 0, Mask); 2083 2084 // For the mask from the second pair... 2085 fillNewShuffleMask(Context, J, NumElemI, NumInElemI, NumInElemJ, 2086 NumInElemI, Mask); 2087 2088 return ConstantVector::get(Mask); 2089 } 2090 2091 bool BBVectorize::expandIEChain(LLVMContext& Context, Instruction *I, 2092 Instruction *J, unsigned o, Value *&LOp, 2093 unsigned numElemL, 2094 Type *ArgTypeL, Type *ArgTypeH, 2095 bool IBeforeJ, unsigned IdxOff) { 2096 bool ExpandedIEChain = false; 2097 if (InsertElementInst *LIE = dyn_cast<InsertElementInst>(LOp)) { 2098 // If we have a pure insertelement chain, then this can be rewritten 2099 // into a chain that directly builds the larger type. 2100 bool PureChain = true; 2101 InsertElementInst *LIENext = LIE; 2102 do { 2103 if (!isa<UndefValue>(LIENext->getOperand(0)) && 2104 !isa<InsertElementInst>(LIENext->getOperand(0))) { 2105 PureChain = false; 2106 break; 2107 } 2108 } while ((LIENext = 2109 dyn_cast<InsertElementInst>(LIENext->getOperand(0)))); 2110 2111 if (PureChain) { 2112 SmallVector<Value *, 8> VectElemts(numElemL, 2113 UndefValue::get(ArgTypeL->getScalarType())); 2114 InsertElementInst *LIENext = LIE; 2115 do { 2116 unsigned Idx = 2117 cast<ConstantInt>(LIENext->getOperand(2))->getSExtValue(); 2118 VectElemts[Idx] = LIENext->getOperand(1); 2119 } while ((LIENext = 2120 dyn_cast<InsertElementInst>(LIENext->getOperand(0)))); 2121 2122 LIENext = 0; 2123 Value *LIEPrev = UndefValue::get(ArgTypeH); 2124 for (unsigned i = 0; i < numElemL; ++i) { 2125 if (isa<UndefValue>(VectElemts[i])) continue; 2126 LIENext = InsertElementInst::Create(LIEPrev, VectElemts[i], 2127 ConstantInt::get(Type::getInt32Ty(Context), 2128 i + IdxOff), 2129 getReplacementName(IBeforeJ ? I : J, 2130 true, o, i+1)); 2131 LIENext->insertBefore(IBeforeJ ? J : I); 2132 LIEPrev = LIENext; 2133 } 2134 2135 LOp = LIENext ? (Value*) LIENext : UndefValue::get(ArgTypeH); 2136 ExpandedIEChain = true; 2137 } 2138 } 2139 2140 return ExpandedIEChain; 2141 } 2142 2143 // Returns the value to be used as the specified operand of the vector 2144 // instruction that fuses I with J. 2145 Value *BBVectorize::getReplacementInput(LLVMContext& Context, Instruction *I, 2146 Instruction *J, unsigned o, bool IBeforeJ) { 2147 Value *CV0 = ConstantInt::get(Type::getInt32Ty(Context), 0); 2148 Value *CV1 = ConstantInt::get(Type::getInt32Ty(Context), 1); 2149 2150 // Compute the fused vector type for this operand 2151 Type *ArgTypeI = I->getOperand(o)->getType(); 2152 Type *ArgTypeJ = J->getOperand(o)->getType(); 2153 VectorType *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ); 2154 2155 Instruction *L = I, *H = J; 2156 Type *ArgTypeL = ArgTypeI, *ArgTypeH = ArgTypeJ; 2157 2158 unsigned numElemL; 2159 if (ArgTypeL->isVectorTy()) 2160 numElemL = cast<VectorType>(ArgTypeL)->getNumElements(); 2161 else 2162 numElemL = 1; 2163 2164 unsigned numElemH; 2165 if (ArgTypeH->isVectorTy()) 2166 numElemH = cast<VectorType>(ArgTypeH)->getNumElements(); 2167 else 2168 numElemH = 1; 2169 2170 Value *LOp = L->getOperand(o); 2171 Value *HOp = H->getOperand(o); 2172 unsigned numElem = VArgType->getNumElements(); 2173 2174 // First, we check if we can reuse the "original" vector outputs (if these 2175 // exist). We might need a shuffle. 2176 ExtractElementInst *LEE = dyn_cast<ExtractElementInst>(LOp); 2177 ExtractElementInst *HEE = dyn_cast<ExtractElementInst>(HOp); 2178 ShuffleVectorInst *LSV = dyn_cast<ShuffleVectorInst>(LOp); 2179 ShuffleVectorInst *HSV = dyn_cast<ShuffleVectorInst>(HOp); 2180 2181 // FIXME: If we're fusing shuffle instructions, then we can't apply this 2182 // optimization. The input vectors to the shuffle might be a different 2183 // length from the shuffle outputs. Unfortunately, the replacement 2184 // shuffle mask has already been formed, and the mask entries are sensitive 2185 // to the sizes of the inputs. 2186 bool IsSizeChangeShuffle = 2187 isa<ShuffleVectorInst>(L) && 2188 (LOp->getType() != L->getType() || HOp->getType() != H->getType()); 2189 2190 if ((LEE || LSV) && (HEE || HSV) && !IsSizeChangeShuffle) { 2191 // We can have at most two unique vector inputs. 2192 bool CanUseInputs = true; 2193 Value *I1, *I2 = 0; 2194 if (LEE) { 2195 I1 = LEE->getOperand(0); 2196 } else { 2197 I1 = LSV->getOperand(0); 2198 I2 = LSV->getOperand(1); 2199 if (I2 == I1 || isa<UndefValue>(I2)) 2200 I2 = 0; 2201 } 2202 2203 if (HEE) { 2204 Value *I3 = HEE->getOperand(0); 2205 if (!I2 && I3 != I1) 2206 I2 = I3; 2207 else if (I3 != I1 && I3 != I2) 2208 CanUseInputs = false; 2209 } else { 2210 Value *I3 = HSV->getOperand(0); 2211 if (!I2 && I3 != I1) 2212 I2 = I3; 2213 else if (I3 != I1 && I3 != I2) 2214 CanUseInputs = false; 2215 2216 if (CanUseInputs) { 2217 Value *I4 = HSV->getOperand(1); 2218 if (!isa<UndefValue>(I4)) { 2219 if (!I2 && I4 != I1) 2220 I2 = I4; 2221 else if (I4 != I1 && I4 != I2) 2222 CanUseInputs = false; 2223 } 2224 } 2225 } 2226 2227 if (CanUseInputs) { 2228 unsigned LOpElem = 2229 cast<VectorType>(cast<Instruction>(LOp)->getOperand(0)->getType()) 2230 ->getNumElements(); 2231 unsigned HOpElem = 2232 cast<VectorType>(cast<Instruction>(HOp)->getOperand(0)->getType()) 2233 ->getNumElements(); 2234 2235 // We have one or two input vectors. We need to map each index of the 2236 // operands to the index of the original vector. 2237 SmallVector<std::pair<int, int>, 8> II(numElem); 2238 for (unsigned i = 0; i < numElemL; ++i) { 2239 int Idx, INum; 2240 if (LEE) { 2241 Idx = 2242 cast<ConstantInt>(LEE->getOperand(1))->getSExtValue(); 2243 INum = LEE->getOperand(0) == I1 ? 0 : 1; 2244 } else { 2245 Idx = LSV->getMaskValue(i); 2246 if (Idx < (int) LOpElem) { 2247 INum = LSV->getOperand(0) == I1 ? 0 : 1; 2248 } else { 2249 Idx -= LOpElem; 2250 INum = LSV->getOperand(1) == I1 ? 0 : 1; 2251 } 2252 } 2253 2254 II[i] = std::pair<int, int>(Idx, INum); 2255 } 2256 for (unsigned i = 0; i < numElemH; ++i) { 2257 int Idx, INum; 2258 if (HEE) { 2259 Idx = 2260 cast<ConstantInt>(HEE->getOperand(1))->getSExtValue(); 2261 INum = HEE->getOperand(0) == I1 ? 0 : 1; 2262 } else { 2263 Idx = HSV->getMaskValue(i); 2264 if (Idx < (int) HOpElem) { 2265 INum = HSV->getOperand(0) == I1 ? 0 : 1; 2266 } else { 2267 Idx -= HOpElem; 2268 INum = HSV->getOperand(1) == I1 ? 0 : 1; 2269 } 2270 } 2271 2272 II[i + numElemL] = std::pair<int, int>(Idx, INum); 2273 } 2274 2275 // We now have an array which tells us from which index of which 2276 // input vector each element of the operand comes. 2277 VectorType *I1T = cast<VectorType>(I1->getType()); 2278 unsigned I1Elem = I1T->getNumElements(); 2279 2280 if (!I2) { 2281 // In this case there is only one underlying vector input. Check for 2282 // the trivial case where we can use the input directly. 2283 if (I1Elem == numElem) { 2284 bool ElemInOrder = true; 2285 for (unsigned i = 0; i < numElem; ++i) { 2286 if (II[i].first != (int) i && II[i].first != -1) { 2287 ElemInOrder = false; 2288 break; 2289 } 2290 } 2291 2292 if (ElemInOrder) 2293 return I1; 2294 } 2295 2296 // A shuffle is needed. 2297 std::vector<Constant *> Mask(numElem); 2298 for (unsigned i = 0; i < numElem; ++i) { 2299 int Idx = II[i].first; 2300 if (Idx == -1) 2301 Mask[i] = UndefValue::get(Type::getInt32Ty(Context)); 2302 else 2303 Mask[i] = ConstantInt::get(Type::getInt32Ty(Context), Idx); 2304 } 2305 2306 Instruction *S = 2307 new ShuffleVectorInst(I1, UndefValue::get(I1T), 2308 ConstantVector::get(Mask), 2309 getReplacementName(IBeforeJ ? I : J, 2310 true, o)); 2311 S->insertBefore(IBeforeJ ? J : I); 2312 return S; 2313 } 2314 2315 VectorType *I2T = cast<VectorType>(I2->getType()); 2316 unsigned I2Elem = I2T->getNumElements(); 2317 2318 // This input comes from two distinct vectors. The first step is to 2319 // make sure that both vectors are the same length. If not, the 2320 // smaller one will need to grow before they can be shuffled together. 2321 if (I1Elem < I2Elem) { 2322 std::vector<Constant *> Mask(I2Elem); 2323 unsigned v = 0; 2324 for (; v < I1Elem; ++v) 2325 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v); 2326 for (; v < I2Elem; ++v) 2327 Mask[v] = UndefValue::get(Type::getInt32Ty(Context)); 2328 2329 Instruction *NewI1 = 2330 new ShuffleVectorInst(I1, UndefValue::get(I1T), 2331 ConstantVector::get(Mask), 2332 getReplacementName(IBeforeJ ? I : J, 2333 true, o, 1)); 2334 NewI1->insertBefore(IBeforeJ ? J : I); 2335 I1 = NewI1; 2336 I1T = I2T; 2337 I1Elem = I2Elem; 2338 } else if (I1Elem > I2Elem) { 2339 std::vector<Constant *> Mask(I1Elem); 2340 unsigned v = 0; 2341 for (; v < I2Elem; ++v) 2342 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v); 2343 for (; v < I1Elem; ++v) 2344 Mask[v] = UndefValue::get(Type::getInt32Ty(Context)); 2345 2346 Instruction *NewI2 = 2347 new ShuffleVectorInst(I2, UndefValue::get(I2T), 2348 ConstantVector::get(Mask), 2349 getReplacementName(IBeforeJ ? I : J, 2350 true, o, 1)); 2351 NewI2->insertBefore(IBeforeJ ? J : I); 2352 I2 = NewI2; 2353 I2T = I1T; 2354 I2Elem = I1Elem; 2355 } 2356 2357 // Now that both I1 and I2 are the same length we can shuffle them 2358 // together (and use the result). 2359 std::vector<Constant *> Mask(numElem); 2360 for (unsigned v = 0; v < numElem; ++v) { 2361 if (II[v].first == -1) { 2362 Mask[v] = UndefValue::get(Type::getInt32Ty(Context)); 2363 } else { 2364 int Idx = II[v].first + II[v].second * I1Elem; 2365 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), Idx); 2366 } 2367 } 2368 2369 Instruction *NewOp = 2370 new ShuffleVectorInst(I1, I2, ConstantVector::get(Mask), 2371 getReplacementName(IBeforeJ ? I : J, true, o)); 2372 NewOp->insertBefore(IBeforeJ ? J : I); 2373 return NewOp; 2374 } 2375 } 2376 2377 Type *ArgType = ArgTypeL; 2378 if (numElemL < numElemH) { 2379 if (numElemL == 1 && expandIEChain(Context, I, J, o, HOp, numElemH, 2380 ArgTypeL, VArgType, IBeforeJ, 1)) { 2381 // This is another short-circuit case: we're combining a scalar into 2382 // a vector that is formed by an IE chain. We've just expanded the IE 2383 // chain, now insert the scalar and we're done. 2384 2385 Instruction *S = InsertElementInst::Create(HOp, LOp, CV0, 2386 getReplacementName(IBeforeJ ? I : J, true, o)); 2387 S->insertBefore(IBeforeJ ? J : I); 2388 return S; 2389 } else if (!expandIEChain(Context, I, J, o, LOp, numElemL, ArgTypeL, 2390 ArgTypeH, IBeforeJ)) { 2391 // The two vector inputs to the shuffle must be the same length, 2392 // so extend the smaller vector to be the same length as the larger one. 2393 Instruction *NLOp; 2394 if (numElemL > 1) { 2395 2396 std::vector<Constant *> Mask(numElemH); 2397 unsigned v = 0; 2398 for (; v < numElemL; ++v) 2399 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v); 2400 for (; v < numElemH; ++v) 2401 Mask[v] = UndefValue::get(Type::getInt32Ty(Context)); 2402 2403 NLOp = new ShuffleVectorInst(LOp, UndefValue::get(ArgTypeL), 2404 ConstantVector::get(Mask), 2405 getReplacementName(IBeforeJ ? I : J, 2406 true, o, 1)); 2407 } else { 2408 NLOp = InsertElementInst::Create(UndefValue::get(ArgTypeH), LOp, CV0, 2409 getReplacementName(IBeforeJ ? I : J, 2410 true, o, 1)); 2411 } 2412 2413 NLOp->insertBefore(IBeforeJ ? J : I); 2414 LOp = NLOp; 2415 } 2416 2417 ArgType = ArgTypeH; 2418 } else if (numElemL > numElemH) { 2419 if (numElemH == 1 && expandIEChain(Context, I, J, o, LOp, numElemL, 2420 ArgTypeH, VArgType, IBeforeJ)) { 2421 Instruction *S = 2422 InsertElementInst::Create(LOp, HOp, 2423 ConstantInt::get(Type::getInt32Ty(Context), 2424 numElemL), 2425 getReplacementName(IBeforeJ ? I : J, 2426 true, o)); 2427 S->insertBefore(IBeforeJ ? J : I); 2428 return S; 2429 } else if (!expandIEChain(Context, I, J, o, HOp, numElemH, ArgTypeH, 2430 ArgTypeL, IBeforeJ)) { 2431 Instruction *NHOp; 2432 if (numElemH > 1) { 2433 std::vector<Constant *> Mask(numElemL); 2434 unsigned v = 0; 2435 for (; v < numElemH; ++v) 2436 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v); 2437 for (; v < numElemL; ++v) 2438 Mask[v] = UndefValue::get(Type::getInt32Ty(Context)); 2439 2440 NHOp = new ShuffleVectorInst(HOp, UndefValue::get(ArgTypeH), 2441 ConstantVector::get(Mask), 2442 getReplacementName(IBeforeJ ? I : J, 2443 true, o, 1)); 2444 } else { 2445 NHOp = InsertElementInst::Create(UndefValue::get(ArgTypeL), HOp, CV0, 2446 getReplacementName(IBeforeJ ? I : J, 2447 true, o, 1)); 2448 } 2449 2450 NHOp->insertBefore(IBeforeJ ? J : I); 2451 HOp = NHOp; 2452 } 2453 } 2454 2455 if (ArgType->isVectorTy()) { 2456 unsigned numElem = cast<VectorType>(VArgType)->getNumElements(); 2457 std::vector<Constant*> Mask(numElem); 2458 for (unsigned v = 0; v < numElem; ++v) { 2459 unsigned Idx = v; 2460 // If the low vector was expanded, we need to skip the extra 2461 // undefined entries. 2462 if (v >= numElemL && numElemH > numElemL) 2463 Idx += (numElemH - numElemL); 2464 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), Idx); 2465 } 2466 2467 Instruction *BV = new ShuffleVectorInst(LOp, HOp, 2468 ConstantVector::get(Mask), 2469 getReplacementName(IBeforeJ ? I : J, true, o)); 2470 BV->insertBefore(IBeforeJ ? J : I); 2471 return BV; 2472 } 2473 2474 Instruction *BV1 = InsertElementInst::Create( 2475 UndefValue::get(VArgType), LOp, CV0, 2476 getReplacementName(IBeforeJ ? I : J, 2477 true, o, 1)); 2478 BV1->insertBefore(IBeforeJ ? J : I); 2479 Instruction *BV2 = InsertElementInst::Create(BV1, HOp, CV1, 2480 getReplacementName(IBeforeJ ? I : J, 2481 true, o, 2)); 2482 BV2->insertBefore(IBeforeJ ? J : I); 2483 return BV2; 2484 } 2485 2486 // This function creates an array of values that will be used as the inputs 2487 // to the vector instruction that fuses I with J. 2488 void BBVectorize::getReplacementInputsForPair(LLVMContext& Context, 2489 Instruction *I, Instruction *J, 2490 SmallVector<Value *, 3> &ReplacedOperands, 2491 bool IBeforeJ) { 2492 unsigned NumOperands = I->getNumOperands(); 2493 2494 for (unsigned p = 0, o = NumOperands-1; p < NumOperands; ++p, --o) { 2495 // Iterate backward so that we look at the store pointer 2496 // first and know whether or not we need to flip the inputs. 2497 2498 if (isa<LoadInst>(I) || (o == 1 && isa<StoreInst>(I))) { 2499 // This is the pointer for a load/store instruction. 2500 ReplacedOperands[o] = getReplacementPointerInput(Context, I, J, o); 2501 continue; 2502 } else if (isa<CallInst>(I)) { 2503 Function *F = cast<CallInst>(I)->getCalledFunction(); 2504 unsigned IID = F->getIntrinsicID(); 2505 if (o == NumOperands-1) { 2506 BasicBlock &BB = *I->getParent(); 2507 2508 Module *M = BB.getParent()->getParent(); 2509 Type *ArgTypeI = I->getType(); 2510 Type *ArgTypeJ = J->getType(); 2511 Type *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ); 2512 2513 ReplacedOperands[o] = Intrinsic::getDeclaration(M, 2514 (Intrinsic::ID) IID, VArgType); 2515 continue; 2516 } else if (IID == Intrinsic::powi && o == 1) { 2517 // The second argument of powi is a single integer and we've already 2518 // checked that both arguments are equal. As a result, we just keep 2519 // I's second argument. 2520 ReplacedOperands[o] = I->getOperand(o); 2521 continue; 2522 } 2523 } else if (isa<ShuffleVectorInst>(I) && o == NumOperands-1) { 2524 ReplacedOperands[o] = getReplacementShuffleMask(Context, I, J); 2525 continue; 2526 } 2527 2528 ReplacedOperands[o] = getReplacementInput(Context, I, J, o, IBeforeJ); 2529 } 2530 } 2531 2532 // This function creates two values that represent the outputs of the 2533 // original I and J instructions. These are generally vector shuffles 2534 // or extracts. In many cases, these will end up being unused and, thus, 2535 // eliminated by later passes. 2536 void BBVectorize::replaceOutputsOfPair(LLVMContext& Context, Instruction *I, 2537 Instruction *J, Instruction *K, 2538 Instruction *&InsertionPt, 2539 Instruction *&K1, Instruction *&K2) { 2540 if (isa<StoreInst>(I)) { 2541 AA->replaceWithNewValue(I, K); 2542 AA->replaceWithNewValue(J, K); 2543 } else { 2544 Type *IType = I->getType(); 2545 Type *JType = J->getType(); 2546 2547 VectorType *VType = getVecTypeForPair(IType, JType); 2548 unsigned numElem = VType->getNumElements(); 2549 2550 unsigned numElemI, numElemJ; 2551 if (IType->isVectorTy()) 2552 numElemI = cast<VectorType>(IType)->getNumElements(); 2553 else 2554 numElemI = 1; 2555 2556 if (JType->isVectorTy()) 2557 numElemJ = cast<VectorType>(JType)->getNumElements(); 2558 else 2559 numElemJ = 1; 2560 2561 if (IType->isVectorTy()) { 2562 std::vector<Constant*> Mask1(numElemI), Mask2(numElemI); 2563 for (unsigned v = 0; v < numElemI; ++v) { 2564 Mask1[v] = ConstantInt::get(Type::getInt32Ty(Context), v); 2565 Mask2[v] = ConstantInt::get(Type::getInt32Ty(Context), numElemJ+v); 2566 } 2567 2568 K1 = new ShuffleVectorInst(K, UndefValue::get(VType), 2569 ConstantVector::get( Mask1), 2570 getReplacementName(K, false, 1)); 2571 } else { 2572 Value *CV0 = ConstantInt::get(Type::getInt32Ty(Context), 0); 2573 K1 = ExtractElementInst::Create(K, CV0, 2574 getReplacementName(K, false, 1)); 2575 } 2576 2577 if (JType->isVectorTy()) { 2578 std::vector<Constant*> Mask1(numElemJ), Mask2(numElemJ); 2579 for (unsigned v = 0; v < numElemJ; ++v) { 2580 Mask1[v] = ConstantInt::get(Type::getInt32Ty(Context), v); 2581 Mask2[v] = ConstantInt::get(Type::getInt32Ty(Context), numElemI+v); 2582 } 2583 2584 K2 = new ShuffleVectorInst(K, UndefValue::get(VType), 2585 ConstantVector::get( Mask2), 2586 getReplacementName(K, false, 2)); 2587 } else { 2588 Value *CV1 = ConstantInt::get(Type::getInt32Ty(Context), numElem-1); 2589 K2 = ExtractElementInst::Create(K, CV1, 2590 getReplacementName(K, false, 2)); 2591 } 2592 2593 K1->insertAfter(K); 2594 K2->insertAfter(K1); 2595 InsertionPt = K2; 2596 } 2597 } 2598 2599 // Move all uses of the function I (including pairing-induced uses) after J. 2600 bool BBVectorize::canMoveUsesOfIAfterJ(BasicBlock &BB, 2601 std::multimap<Value *, Value *> &LoadMoveSet, 2602 Instruction *I, Instruction *J) { 2603 // Skip to the first instruction past I. 2604 BasicBlock::iterator L = llvm::next(BasicBlock::iterator(I)); 2605 2606 DenseSet<Value *> Users; 2607 AliasSetTracker WriteSet(*AA); 2608 for (; cast<Instruction>(L) != J; ++L) 2609 (void) trackUsesOfI(Users, WriteSet, I, L, true, &LoadMoveSet); 2610 2611 assert(cast<Instruction>(L) == J && 2612 "Tracking has not proceeded far enough to check for dependencies"); 2613 // If J is now in the use set of I, then trackUsesOfI will return true 2614 // and we have a dependency cycle (and the fusing operation must abort). 2615 return !trackUsesOfI(Users, WriteSet, I, J, true, &LoadMoveSet); 2616 } 2617 2618 // Move all uses of the function I (including pairing-induced uses) after J. 2619 void BBVectorize::moveUsesOfIAfterJ(BasicBlock &BB, 2620 std::multimap<Value *, Value *> &LoadMoveSet, 2621 Instruction *&InsertionPt, 2622 Instruction *I, Instruction *J) { 2623 // Skip to the first instruction past I. 2624 BasicBlock::iterator L = llvm::next(BasicBlock::iterator(I)); 2625 2626 DenseSet<Value *> Users; 2627 AliasSetTracker WriteSet(*AA); 2628 for (; cast<Instruction>(L) != J;) { 2629 if (trackUsesOfI(Users, WriteSet, I, L, true, &LoadMoveSet)) { 2630 // Move this instruction 2631 Instruction *InstToMove = L; ++L; 2632 2633 DEBUG(dbgs() << "BBV: moving: " << *InstToMove << 2634 " to after " << *InsertionPt << "\n"); 2635 InstToMove->removeFromParent(); 2636 InstToMove->insertAfter(InsertionPt); 2637 InsertionPt = InstToMove; 2638 } else { 2639 ++L; 2640 } 2641 } 2642 } 2643 2644 // Collect all load instruction that are in the move set of a given first 2645 // pair member. These loads depend on the first instruction, I, and so need 2646 // to be moved after J (the second instruction) when the pair is fused. 2647 void BBVectorize::collectPairLoadMoveSet(BasicBlock &BB, 2648 DenseMap<Value *, Value *> &ChosenPairs, 2649 std::multimap<Value *, Value *> &LoadMoveSet, 2650 Instruction *I) { 2651 // Skip to the first instruction past I. 2652 BasicBlock::iterator L = llvm::next(BasicBlock::iterator(I)); 2653 2654 DenseSet<Value *> Users; 2655 AliasSetTracker WriteSet(*AA); 2656 2657 // Note: We cannot end the loop when we reach J because J could be moved 2658 // farther down the use chain by another instruction pairing. Also, J 2659 // could be before I if this is an inverted input. 2660 for (BasicBlock::iterator E = BB.end(); cast<Instruction>(L) != E; ++L) { 2661 if (trackUsesOfI(Users, WriteSet, I, L)) { 2662 if (L->mayReadFromMemory()) 2663 LoadMoveSet.insert(ValuePair(L, I)); 2664 } 2665 } 2666 } 2667 2668 // In cases where both load/stores and the computation of their pointers 2669 // are chosen for vectorization, we can end up in a situation where the 2670 // aliasing analysis starts returning different query results as the 2671 // process of fusing instruction pairs continues. Because the algorithm 2672 // relies on finding the same use trees here as were found earlier, we'll 2673 // need to precompute the necessary aliasing information here and then 2674 // manually update it during the fusion process. 2675 void BBVectorize::collectLoadMoveSet(BasicBlock &BB, 2676 std::vector<Value *> &PairableInsts, 2677 DenseMap<Value *, Value *> &ChosenPairs, 2678 std::multimap<Value *, Value *> &LoadMoveSet) { 2679 for (std::vector<Value *>::iterator PI = PairableInsts.begin(), 2680 PIE = PairableInsts.end(); PI != PIE; ++PI) { 2681 DenseMap<Value *, Value *>::iterator P = ChosenPairs.find(*PI); 2682 if (P == ChosenPairs.end()) continue; 2683 2684 Instruction *I = cast<Instruction>(P->first); 2685 collectPairLoadMoveSet(BB, ChosenPairs, LoadMoveSet, I); 2686 } 2687 } 2688 2689 // When the first instruction in each pair is cloned, it will inherit its 2690 // parent's metadata. This metadata must be combined with that of the other 2691 // instruction in a safe way. 2692 void BBVectorize::combineMetadata(Instruction *K, const Instruction *J) { 2693 SmallVector<std::pair<unsigned, MDNode*>, 4> Metadata; 2694 K->getAllMetadataOtherThanDebugLoc(Metadata); 2695 for (unsigned i = 0, n = Metadata.size(); i < n; ++i) { 2696 unsigned Kind = Metadata[i].first; 2697 MDNode *JMD = J->getMetadata(Kind); 2698 MDNode *KMD = Metadata[i].second; 2699 2700 switch (Kind) { 2701 default: 2702 K->setMetadata(Kind, 0); // Remove unknown metadata 2703 break; 2704 case LLVMContext::MD_tbaa: 2705 K->setMetadata(Kind, MDNode::getMostGenericTBAA(JMD, KMD)); 2706 break; 2707 case LLVMContext::MD_fpmath: 2708 K->setMetadata(Kind, MDNode::getMostGenericFPMath(JMD, KMD)); 2709 break; 2710 } 2711 } 2712 } 2713 2714 // This function fuses the chosen instruction pairs into vector instructions, 2715 // taking care preserve any needed scalar outputs and, then, it reorders the 2716 // remaining instructions as needed (users of the first member of the pair 2717 // need to be moved to after the location of the second member of the pair 2718 // because the vector instruction is inserted in the location of the pair's 2719 // second member). 2720 void BBVectorize::fuseChosenPairs(BasicBlock &BB, 2721 std::vector<Value *> &PairableInsts, 2722 DenseMap<Value *, Value *> &ChosenPairs, 2723 DenseSet<ValuePair> &FixedOrderPairs, 2724 DenseMap<VPPair, unsigned> &PairConnectionTypes, 2725 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 2726 std::multimap<ValuePair, ValuePair> &ConnectedPairDeps) { 2727 LLVMContext& Context = BB.getContext(); 2728 2729 // During the vectorization process, the order of the pairs to be fused 2730 // could be flipped. So we'll add each pair, flipped, into the ChosenPairs 2731 // list. After a pair is fused, the flipped pair is removed from the list. 2732 DenseSet<ValuePair> FlippedPairs; 2733 for (DenseMap<Value *, Value *>::iterator P = ChosenPairs.begin(), 2734 E = ChosenPairs.end(); P != E; ++P) 2735 FlippedPairs.insert(ValuePair(P->second, P->first)); 2736 for (DenseSet<ValuePair>::iterator P = FlippedPairs.begin(), 2737 E = FlippedPairs.end(); P != E; ++P) 2738 ChosenPairs.insert(*P); 2739 2740 std::multimap<Value *, Value *> LoadMoveSet; 2741 collectLoadMoveSet(BB, PairableInsts, ChosenPairs, LoadMoveSet); 2742 2743 DEBUG(dbgs() << "BBV: initial: \n" << BB << "\n"); 2744 2745 for (BasicBlock::iterator PI = BB.getFirstInsertionPt(); PI != BB.end();) { 2746 DenseMap<Value *, Value *>::iterator P = ChosenPairs.find(PI); 2747 if (P == ChosenPairs.end()) { 2748 ++PI; 2749 continue; 2750 } 2751 2752 if (getDepthFactor(P->first) == 0) { 2753 // These instructions are not really fused, but are tracked as though 2754 // they are. Any case in which it would be interesting to fuse them 2755 // will be taken care of by InstCombine. 2756 --NumFusedOps; 2757 ++PI; 2758 continue; 2759 } 2760 2761 Instruction *I = cast<Instruction>(P->first), 2762 *J = cast<Instruction>(P->second); 2763 2764 DEBUG(dbgs() << "BBV: fusing: " << *I << 2765 " <-> " << *J << "\n"); 2766 2767 // Remove the pair and flipped pair from the list. 2768 DenseMap<Value *, Value *>::iterator FP = ChosenPairs.find(P->second); 2769 assert(FP != ChosenPairs.end() && "Flipped pair not found in list"); 2770 ChosenPairs.erase(FP); 2771 ChosenPairs.erase(P); 2772 2773 if (!canMoveUsesOfIAfterJ(BB, LoadMoveSet, I, J)) { 2774 DEBUG(dbgs() << "BBV: fusion of: " << *I << 2775 " <-> " << *J << 2776 " aborted because of non-trivial dependency cycle\n"); 2777 --NumFusedOps; 2778 ++PI; 2779 continue; 2780 } 2781 2782 // If the pair must have the other order, then flip it. 2783 bool FlipPairOrder = FixedOrderPairs.count(ValuePair(J, I)); 2784 if (!FlipPairOrder && !FixedOrderPairs.count(ValuePair(I, J))) { 2785 // This pair does not have a fixed order, and so we might want to 2786 // flip it if that will yield fewer shuffles. We count the number 2787 // of dependencies connected via swaps, and those directly connected, 2788 // and flip the order if the number of swaps is greater. 2789 bool OrigOrder = true; 2790 VPPIteratorPair IP = ConnectedPairDeps.equal_range(ValuePair(I, J)); 2791 if (IP.first == ConnectedPairDeps.end()) { 2792 IP = ConnectedPairDeps.equal_range(ValuePair(J, I)); 2793 OrigOrder = false; 2794 } 2795 2796 if (IP.first != ConnectedPairDeps.end()) { 2797 unsigned NumDepsDirect = 0, NumDepsSwap = 0; 2798 for (std::multimap<ValuePair, ValuePair>::iterator Q = IP.first; 2799 Q != IP.second; ++Q) { 2800 DenseMap<VPPair, unsigned>::iterator R = 2801 PairConnectionTypes.find(VPPair(Q->second, Q->first)); 2802 assert(R != PairConnectionTypes.end() && 2803 "Cannot find pair connection type"); 2804 if (R->second == PairConnectionDirect) 2805 ++NumDepsDirect; 2806 else if (R->second == PairConnectionSwap) 2807 ++NumDepsSwap; 2808 } 2809 2810 if (!OrigOrder) 2811 std::swap(NumDepsDirect, NumDepsSwap); 2812 2813 if (NumDepsSwap > NumDepsDirect) { 2814 FlipPairOrder = true; 2815 DEBUG(dbgs() << "BBV: reordering pair: " << *I << 2816 " <-> " << *J << "\n"); 2817 } 2818 } 2819 } 2820 2821 Instruction *L = I, *H = J; 2822 if (FlipPairOrder) 2823 std::swap(H, L); 2824 2825 // If the pair being fused uses the opposite order from that in the pair 2826 // connection map, then we need to flip the types. 2827 VPPIteratorPair IP = ConnectedPairs.equal_range(ValuePair(H, L)); 2828 for (std::multimap<ValuePair, ValuePair>::iterator Q = IP.first; 2829 Q != IP.second; ++Q) { 2830 DenseMap<VPPair, unsigned>::iterator R = PairConnectionTypes.find(*Q); 2831 assert(R != PairConnectionTypes.end() && 2832 "Cannot find pair connection type"); 2833 if (R->second == PairConnectionDirect) 2834 R->second = PairConnectionSwap; 2835 else if (R->second == PairConnectionSwap) 2836 R->second = PairConnectionDirect; 2837 } 2838 2839 bool LBeforeH = !FlipPairOrder; 2840 unsigned NumOperands = I->getNumOperands(); 2841 SmallVector<Value *, 3> ReplacedOperands(NumOperands); 2842 getReplacementInputsForPair(Context, L, H, ReplacedOperands, 2843 LBeforeH); 2844 2845 // Make a copy of the original operation, change its type to the vector 2846 // type and replace its operands with the vector operands. 2847 Instruction *K = L->clone(); 2848 if (L->hasName()) 2849 K->takeName(L); 2850 else if (H->hasName()) 2851 K->takeName(H); 2852 2853 if (!isa<StoreInst>(K)) 2854 K->mutateType(getVecTypeForPair(L->getType(), H->getType())); 2855 2856 combineMetadata(K, H); 2857 2858 for (unsigned o = 0; o < NumOperands; ++o) 2859 K->setOperand(o, ReplacedOperands[o]); 2860 2861 K->insertAfter(J); 2862 2863 // Instruction insertion point: 2864 Instruction *InsertionPt = K; 2865 Instruction *K1 = 0, *K2 = 0; 2866 replaceOutputsOfPair(Context, L, H, K, InsertionPt, K1, K2); 2867 2868 // The use tree of the first original instruction must be moved to after 2869 // the location of the second instruction. The entire use tree of the 2870 // first instruction is disjoint from the input tree of the second 2871 // (by definition), and so commutes with it. 2872 2873 moveUsesOfIAfterJ(BB, LoadMoveSet, InsertionPt, I, J); 2874 2875 if (!isa<StoreInst>(I)) { 2876 L->replaceAllUsesWith(K1); 2877 H->replaceAllUsesWith(K2); 2878 AA->replaceWithNewValue(L, K1); 2879 AA->replaceWithNewValue(H, K2); 2880 } 2881 2882 // Instructions that may read from memory may be in the load move set. 2883 // Once an instruction is fused, we no longer need its move set, and so 2884 // the values of the map never need to be updated. However, when a load 2885 // is fused, we need to merge the entries from both instructions in the 2886 // pair in case those instructions were in the move set of some other 2887 // yet-to-be-fused pair. The loads in question are the keys of the map. 2888 if (I->mayReadFromMemory()) { 2889 std::vector<ValuePair> NewSetMembers; 2890 VPIteratorPair IPairRange = LoadMoveSet.equal_range(I); 2891 VPIteratorPair JPairRange = LoadMoveSet.equal_range(J); 2892 for (std::multimap<Value *, Value *>::iterator N = IPairRange.first; 2893 N != IPairRange.second; ++N) 2894 NewSetMembers.push_back(ValuePair(K, N->second)); 2895 for (std::multimap<Value *, Value *>::iterator N = JPairRange.first; 2896 N != JPairRange.second; ++N) 2897 NewSetMembers.push_back(ValuePair(K, N->second)); 2898 for (std::vector<ValuePair>::iterator A = NewSetMembers.begin(), 2899 AE = NewSetMembers.end(); A != AE; ++A) 2900 LoadMoveSet.insert(*A); 2901 } 2902 2903 // Before removing I, set the iterator to the next instruction. 2904 PI = llvm::next(BasicBlock::iterator(I)); 2905 if (cast<Instruction>(PI) == J) 2906 ++PI; 2907 2908 SE->forgetValue(I); 2909 SE->forgetValue(J); 2910 I->eraseFromParent(); 2911 J->eraseFromParent(); 2912 2913 DEBUG(if (PrintAfterEveryPair) dbgs() << "BBV: block is now: \n" << 2914 BB << "\n"); 2915 } 2916 2917 DEBUG(dbgs() << "BBV: final: \n" << BB << "\n"); 2918 } 2919} 2920 2921char BBVectorize::ID = 0; 2922static const char bb_vectorize_name[] = "Basic-Block Vectorization"; 2923INITIALIZE_PASS_BEGIN(BBVectorize, BBV_NAME, bb_vectorize_name, false, false) 2924INITIALIZE_AG_DEPENDENCY(AliasAnalysis) 2925INITIALIZE_PASS_DEPENDENCY(DominatorTree) 2926INITIALIZE_PASS_DEPENDENCY(ScalarEvolution) 2927INITIALIZE_PASS_END(BBVectorize, BBV_NAME, bb_vectorize_name, false, false) 2928 2929BasicBlockPass *llvm::createBBVectorizePass(const VectorizeConfig &C) { 2930 return new BBVectorize(C); 2931} 2932 2933bool 2934llvm::vectorizeBasicBlock(Pass *P, BasicBlock &BB, const VectorizeConfig &C) { 2935 BBVectorize BBVectorizer(P, C); 2936 return BBVectorizer.vectorizeBB(BB); 2937} 2938 2939//===----------------------------------------------------------------------===// 2940VectorizeConfig::VectorizeConfig() { 2941 VectorBits = ::VectorBits; 2942 VectorizeBools = !::NoBools; 2943 VectorizeInts = !::NoInts; 2944 VectorizeFloats = !::NoFloats; 2945 VectorizePointers = !::NoPointers; 2946 VectorizeCasts = !::NoCasts; 2947 VectorizeMath = !::NoMath; 2948 VectorizeFMA = !::NoFMA; 2949 VectorizeSelect = !::NoSelect; 2950 VectorizeCmp = !::NoCmp; 2951 VectorizeGEP = !::NoGEP; 2952 VectorizeMemOps = !::NoMemOps; 2953 AlignedOnly = ::AlignedOnly; 2954 ReqChainDepth= ::ReqChainDepth; 2955 SearchLimit = ::SearchLimit; 2956 MaxCandPairsForCycleCheck = ::MaxCandPairsForCycleCheck; 2957 SplatBreaksChain = ::SplatBreaksChain; 2958 MaxInsts = ::MaxInsts; 2959 MaxIter = ::MaxIter; 2960 Pow2LenOnly = ::Pow2LenOnly; 2961 NoMemOpBoost = ::NoMemOpBoost; 2962 FastDep = ::FastDep; 2963} 2964