BBVectorize.cpp revision be04929f7fd76a921540e9901f24563e51dc1219
1//===- BBVectorize.cpp - A Basic-Block Vectorizer -------------------------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file implements a basic-block vectorization pass. The algorithm was 11// inspired by that used by the Vienna MAP Vectorizor by Franchetti and Kral, 12// et al. It works by looking for chains of pairable operations and then 13// pairing them. 14// 15//===----------------------------------------------------------------------===// 16 17#define BBV_NAME "bb-vectorize" 18#define DEBUG_TYPE BBV_NAME 19#include "llvm/Transforms/Vectorize.h" 20#include "llvm/ADT/DenseMap.h" 21#include "llvm/ADT/DenseSet.h" 22#include "llvm/ADT/STLExtras.h" 23#include "llvm/ADT/SmallSet.h" 24#include "llvm/ADT/SmallVector.h" 25#include "llvm/ADT/Statistic.h" 26#include "llvm/ADT/StringExtras.h" 27#include "llvm/Analysis/AliasAnalysis.h" 28#include "llvm/Analysis/AliasSetTracker.h" 29#include "llvm/Analysis/Dominators.h" 30#include "llvm/Analysis/ScalarEvolution.h" 31#include "llvm/Analysis/ScalarEvolutionExpressions.h" 32#include "llvm/Analysis/TargetTransformInfo.h" 33#include "llvm/Analysis/ValueTracking.h" 34#include "llvm/IR/Constants.h" 35#include "llvm/IR/DataLayout.h" 36#include "llvm/IR/DerivedTypes.h" 37#include "llvm/IR/Function.h" 38#include "llvm/IR/Instructions.h" 39#include "llvm/IR/IntrinsicInst.h" 40#include "llvm/IR/Intrinsics.h" 41#include "llvm/IR/LLVMContext.h" 42#include "llvm/IR/Metadata.h" 43#include "llvm/IR/Type.h" 44#include "llvm/Pass.h" 45#include "llvm/Support/CommandLine.h" 46#include "llvm/Support/Debug.h" 47#include "llvm/Support/ValueHandle.h" 48#include "llvm/Support/raw_ostream.h" 49#include "llvm/Transforms/Utils/Local.h" 50#include <algorithm> 51#include <map> 52using namespace llvm; 53 54static cl::opt<bool> 55IgnoreTargetInfo("bb-vectorize-ignore-target-info", cl::init(false), 56 cl::Hidden, cl::desc("Ignore target information")); 57 58static cl::opt<unsigned> 59ReqChainDepth("bb-vectorize-req-chain-depth", cl::init(6), cl::Hidden, 60 cl::desc("The required chain depth for vectorization")); 61 62static cl::opt<bool> 63UseChainDepthWithTI("bb-vectorize-use-chain-depth", cl::init(false), 64 cl::Hidden, cl::desc("Use the chain depth requirement with" 65 " target information")); 66 67static cl::opt<unsigned> 68SearchLimit("bb-vectorize-search-limit", cl::init(400), cl::Hidden, 69 cl::desc("The maximum search distance for instruction pairs")); 70 71static cl::opt<bool> 72SplatBreaksChain("bb-vectorize-splat-breaks-chain", cl::init(false), cl::Hidden, 73 cl::desc("Replicating one element to a pair breaks the chain")); 74 75static cl::opt<unsigned> 76VectorBits("bb-vectorize-vector-bits", cl::init(128), cl::Hidden, 77 cl::desc("The size of the native vector registers")); 78 79static cl::opt<unsigned> 80MaxIter("bb-vectorize-max-iter", cl::init(0), cl::Hidden, 81 cl::desc("The maximum number of pairing iterations")); 82 83static cl::opt<bool> 84Pow2LenOnly("bb-vectorize-pow2-len-only", cl::init(false), cl::Hidden, 85 cl::desc("Don't try to form non-2^n-length vectors")); 86 87static cl::opt<unsigned> 88MaxInsts("bb-vectorize-max-instr-per-group", cl::init(500), cl::Hidden, 89 cl::desc("The maximum number of pairable instructions per group")); 90 91static cl::opt<unsigned> 92MaxCandPairsForCycleCheck("bb-vectorize-max-cycle-check-pairs", cl::init(200), 93 cl::Hidden, cl::desc("The maximum number of candidate pairs with which to use" 94 " a full cycle check")); 95 96static cl::opt<bool> 97NoBools("bb-vectorize-no-bools", cl::init(false), cl::Hidden, 98 cl::desc("Don't try to vectorize boolean (i1) values")); 99 100static cl::opt<bool> 101NoInts("bb-vectorize-no-ints", cl::init(false), cl::Hidden, 102 cl::desc("Don't try to vectorize integer values")); 103 104static cl::opt<bool> 105NoFloats("bb-vectorize-no-floats", cl::init(false), cl::Hidden, 106 cl::desc("Don't try to vectorize floating-point values")); 107 108// FIXME: This should default to false once pointer vector support works. 109static cl::opt<bool> 110NoPointers("bb-vectorize-no-pointers", cl::init(/*false*/ true), cl::Hidden, 111 cl::desc("Don't try to vectorize pointer values")); 112 113static cl::opt<bool> 114NoCasts("bb-vectorize-no-casts", cl::init(false), cl::Hidden, 115 cl::desc("Don't try to vectorize casting (conversion) operations")); 116 117static cl::opt<bool> 118NoMath("bb-vectorize-no-math", cl::init(false), cl::Hidden, 119 cl::desc("Don't try to vectorize floating-point math intrinsics")); 120 121static cl::opt<bool> 122NoFMA("bb-vectorize-no-fma", cl::init(false), cl::Hidden, 123 cl::desc("Don't try to vectorize the fused-multiply-add intrinsic")); 124 125static cl::opt<bool> 126NoSelect("bb-vectorize-no-select", cl::init(false), cl::Hidden, 127 cl::desc("Don't try to vectorize select instructions")); 128 129static cl::opt<bool> 130NoCmp("bb-vectorize-no-cmp", cl::init(false), cl::Hidden, 131 cl::desc("Don't try to vectorize comparison instructions")); 132 133static cl::opt<bool> 134NoGEP("bb-vectorize-no-gep", cl::init(false), cl::Hidden, 135 cl::desc("Don't try to vectorize getelementptr instructions")); 136 137static cl::opt<bool> 138NoMemOps("bb-vectorize-no-mem-ops", cl::init(false), cl::Hidden, 139 cl::desc("Don't try to vectorize loads and stores")); 140 141static cl::opt<bool> 142AlignedOnly("bb-vectorize-aligned-only", cl::init(false), cl::Hidden, 143 cl::desc("Only generate aligned loads and stores")); 144 145static cl::opt<bool> 146NoMemOpBoost("bb-vectorize-no-mem-op-boost", 147 cl::init(false), cl::Hidden, 148 cl::desc("Don't boost the chain-depth contribution of loads and stores")); 149 150static cl::opt<bool> 151FastDep("bb-vectorize-fast-dep", cl::init(false), cl::Hidden, 152 cl::desc("Use a fast instruction dependency analysis")); 153 154#ifndef NDEBUG 155static cl::opt<bool> 156DebugInstructionExamination("bb-vectorize-debug-instruction-examination", 157 cl::init(false), cl::Hidden, 158 cl::desc("When debugging is enabled, output information on the" 159 " instruction-examination process")); 160static cl::opt<bool> 161DebugCandidateSelection("bb-vectorize-debug-candidate-selection", 162 cl::init(false), cl::Hidden, 163 cl::desc("When debugging is enabled, output information on the" 164 " candidate-selection process")); 165static cl::opt<bool> 166DebugPairSelection("bb-vectorize-debug-pair-selection", 167 cl::init(false), cl::Hidden, 168 cl::desc("When debugging is enabled, output information on the" 169 " pair-selection process")); 170static cl::opt<bool> 171DebugCycleCheck("bb-vectorize-debug-cycle-check", 172 cl::init(false), cl::Hidden, 173 cl::desc("When debugging is enabled, output information on the" 174 " cycle-checking process")); 175 176static cl::opt<bool> 177PrintAfterEveryPair("bb-vectorize-debug-print-after-every-pair", 178 cl::init(false), cl::Hidden, 179 cl::desc("When debugging is enabled, dump the basic block after" 180 " every pair is fused")); 181#endif 182 183STATISTIC(NumFusedOps, "Number of operations fused by bb-vectorize"); 184 185namespace { 186 struct BBVectorize : public BasicBlockPass { 187 static char ID; // Pass identification, replacement for typeid 188 189 const VectorizeConfig Config; 190 191 BBVectorize(const VectorizeConfig &C = VectorizeConfig()) 192 : BasicBlockPass(ID), Config(C) { 193 initializeBBVectorizePass(*PassRegistry::getPassRegistry()); 194 } 195 196 BBVectorize(Pass *P, const VectorizeConfig &C) 197 : BasicBlockPass(ID), Config(C) { 198 AA = &P->getAnalysis<AliasAnalysis>(); 199 DT = &P->getAnalysis<DominatorTree>(); 200 SE = &P->getAnalysis<ScalarEvolution>(); 201 TD = P->getAnalysisIfAvailable<DataLayout>(); 202 TTI = IgnoreTargetInfo ? 0 : 203 P->getAnalysisIfAvailable<TargetTransformInfo>(); 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 const TargetTransformInfo *TTI; 222 223 // FIXME: const correct? 224 225 bool vectorizePairs(BasicBlock &BB, bool NonPow2Len = false); 226 227 bool getCandidatePairs(BasicBlock &BB, 228 BasicBlock::iterator &Start, 229 std::multimap<Value *, Value *> &CandidatePairs, 230 DenseSet<ValuePair> &FixedOrderPairs, 231 DenseMap<ValuePair, int> &CandidatePairCostSavings, 232 std::vector<Value *> &PairableInsts, bool NonPow2Len); 233 234 // FIXME: The current implementation does not account for pairs that 235 // are connected in multiple ways. For example: 236 // C1 = A1 / A2; C2 = A2 / A1 (which may be both direct and a swap) 237 enum PairConnectionType { 238 PairConnectionDirect, 239 PairConnectionSwap, 240 PairConnectionSplat 241 }; 242 243 void computeConnectedPairs(std::multimap<Value *, Value *> &CandidatePairs, 244 std::vector<Value *> &PairableInsts, 245 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 246 DenseMap<VPPair, unsigned> &PairConnectionTypes); 247 248 void buildDepMap(BasicBlock &BB, 249 std::multimap<Value *, Value *> &CandidatePairs, 250 std::vector<Value *> &PairableInsts, 251 DenseSet<ValuePair> &PairableInstUsers); 252 253 void choosePairs(std::multimap<Value *, Value *> &CandidatePairs, 254 DenseMap<ValuePair, int> &CandidatePairCostSavings, 255 std::vector<Value *> &PairableInsts, 256 DenseSet<ValuePair> &FixedOrderPairs, 257 DenseMap<VPPair, unsigned> &PairConnectionTypes, 258 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 259 std::multimap<ValuePair, ValuePair> &ConnectedPairDeps, 260 DenseSet<ValuePair> &PairableInstUsers, 261 DenseMap<Value *, Value *>& ChosenPairs); 262 263 void fuseChosenPairs(BasicBlock &BB, 264 std::vector<Value *> &PairableInsts, 265 DenseMap<Value *, Value *>& ChosenPairs, 266 DenseSet<ValuePair> &FixedOrderPairs, 267 DenseMap<VPPair, unsigned> &PairConnectionTypes, 268 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 269 std::multimap<ValuePair, ValuePair> &ConnectedPairDeps); 270 271 272 bool isInstVectorizable(Instruction *I, bool &IsSimpleLoadStore); 273 274 bool areInstsCompatible(Instruction *I, Instruction *J, 275 bool IsSimpleLoadStore, bool NonPow2Len, 276 int &CostSavings, int &FixedOrder); 277 278 bool trackUsesOfI(DenseSet<Value *> &Users, 279 AliasSetTracker &WriteSet, Instruction *I, 280 Instruction *J, bool UpdateUsers = true, 281 std::multimap<Value *, Value *> *LoadMoveSet = 0); 282 283 void computePairsConnectedTo( 284 std::multimap<Value *, Value *> &CandidatePairs, 285 std::vector<Value *> &PairableInsts, 286 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 287 DenseMap<VPPair, unsigned> &PairConnectionTypes, 288 ValuePair P); 289 290 bool pairsConflict(ValuePair P, ValuePair Q, 291 DenseSet<ValuePair> &PairableInstUsers, 292 std::multimap<ValuePair, ValuePair> *PairableInstUserMap = 0); 293 294 bool pairWillFormCycle(ValuePair P, 295 std::multimap<ValuePair, ValuePair> &PairableInstUsers, 296 DenseSet<ValuePair> &CurrentPairs); 297 298 void pruneTreeFor( 299 std::multimap<Value *, Value *> &CandidatePairs, 300 std::vector<Value *> &PairableInsts, 301 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 302 DenseSet<ValuePair> &PairableInstUsers, 303 std::multimap<ValuePair, ValuePair> &PairableInstUserMap, 304 DenseMap<Value *, Value *> &ChosenPairs, 305 DenseMap<ValuePair, size_t> &Tree, 306 DenseSet<ValuePair> &PrunedTree, ValuePair J, 307 bool UseCycleCheck); 308 309 void buildInitialTreeFor( 310 std::multimap<Value *, Value *> &CandidatePairs, 311 std::vector<Value *> &PairableInsts, 312 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 313 DenseSet<ValuePair> &PairableInstUsers, 314 DenseMap<Value *, Value *> &ChosenPairs, 315 DenseMap<ValuePair, size_t> &Tree, ValuePair J); 316 317 void findBestTreeFor( 318 std::multimap<Value *, Value *> &CandidatePairs, 319 DenseMap<ValuePair, int> &CandidatePairCostSavings, 320 std::vector<Value *> &PairableInsts, 321 DenseSet<ValuePair> &FixedOrderPairs, 322 DenseMap<VPPair, unsigned> &PairConnectionTypes, 323 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 324 std::multimap<ValuePair, ValuePair> &ConnectedPairDeps, 325 DenseSet<ValuePair> &PairableInstUsers, 326 std::multimap<ValuePair, ValuePair> &PairableInstUserMap, 327 DenseMap<Value *, Value *> &ChosenPairs, 328 DenseSet<ValuePair> &BestTree, size_t &BestMaxDepth, 329 int &BestEffSize, VPIteratorPair ChoiceRange, 330 bool UseCycleCheck); 331 332 Value *getReplacementPointerInput(LLVMContext& Context, Instruction *I, 333 Instruction *J, unsigned o); 334 335 void fillNewShuffleMask(LLVMContext& Context, Instruction *J, 336 unsigned MaskOffset, unsigned NumInElem, 337 unsigned NumInElem1, unsigned IdxOffset, 338 std::vector<Constant*> &Mask); 339 340 Value *getReplacementShuffleMask(LLVMContext& Context, Instruction *I, 341 Instruction *J); 342 343 bool expandIEChain(LLVMContext& Context, Instruction *I, Instruction *J, 344 unsigned o, Value *&LOp, unsigned numElemL, 345 Type *ArgTypeL, Type *ArgTypeR, bool IBeforeJ, 346 unsigned IdxOff = 0); 347 348 Value *getReplacementInput(LLVMContext& Context, Instruction *I, 349 Instruction *J, unsigned o, bool IBeforeJ); 350 351 void getReplacementInputsForPair(LLVMContext& Context, Instruction *I, 352 Instruction *J, SmallVector<Value *, 3> &ReplacedOperands, 353 bool IBeforeJ); 354 355 void replaceOutputsOfPair(LLVMContext& Context, Instruction *I, 356 Instruction *J, Instruction *K, 357 Instruction *&InsertionPt, Instruction *&K1, 358 Instruction *&K2); 359 360 void collectPairLoadMoveSet(BasicBlock &BB, 361 DenseMap<Value *, Value *> &ChosenPairs, 362 std::multimap<Value *, Value *> &LoadMoveSet, 363 Instruction *I); 364 365 void collectLoadMoveSet(BasicBlock &BB, 366 std::vector<Value *> &PairableInsts, 367 DenseMap<Value *, Value *> &ChosenPairs, 368 std::multimap<Value *, Value *> &LoadMoveSet); 369 370 bool canMoveUsesOfIAfterJ(BasicBlock &BB, 371 std::multimap<Value *, Value *> &LoadMoveSet, 372 Instruction *I, Instruction *J); 373 374 void moveUsesOfIAfterJ(BasicBlock &BB, 375 std::multimap<Value *, Value *> &LoadMoveSet, 376 Instruction *&InsertionPt, 377 Instruction *I, Instruction *J); 378 379 void combineMetadata(Instruction *K, const Instruction *J); 380 381 bool vectorizeBB(BasicBlock &BB) { 382 if (!DT->isReachableFromEntry(&BB)) { 383 DEBUG(dbgs() << "BBV: skipping unreachable " << BB.getName() << 384 " in " << BB.getParent()->getName() << "\n"); 385 return false; 386 } 387 388 DEBUG(if (TTI) dbgs() << "BBV: using target information\n"); 389 390 bool changed = false; 391 // Iterate a sufficient number of times to merge types of size 1 bit, 392 // then 2 bits, then 4, etc. up to half of the target vector width of the 393 // target vector register. 394 unsigned n = 1; 395 for (unsigned v = 2; 396 (TTI || v <= Config.VectorBits) && 397 (!Config.MaxIter || n <= Config.MaxIter); 398 v *= 2, ++n) { 399 DEBUG(dbgs() << "BBV: fusing loop #" << n << 400 " for " << BB.getName() << " in " << 401 BB.getParent()->getName() << "...\n"); 402 if (vectorizePairs(BB)) 403 changed = true; 404 else 405 break; 406 } 407 408 if (changed && !Pow2LenOnly) { 409 ++n; 410 for (; !Config.MaxIter || n <= Config.MaxIter; ++n) { 411 DEBUG(dbgs() << "BBV: fusing for non-2^n-length vectors loop #: " << 412 n << " for " << BB.getName() << " in " << 413 BB.getParent()->getName() << "...\n"); 414 if (!vectorizePairs(BB, true)) break; 415 } 416 } 417 418 DEBUG(dbgs() << "BBV: done!\n"); 419 return changed; 420 } 421 422 virtual bool runOnBasicBlock(BasicBlock &BB) { 423 AA = &getAnalysis<AliasAnalysis>(); 424 DT = &getAnalysis<DominatorTree>(); 425 SE = &getAnalysis<ScalarEvolution>(); 426 TD = getAnalysisIfAvailable<DataLayout>(); 427 TTI = IgnoreTargetInfo ? 0 : 428 getAnalysisIfAvailable<TargetTransformInfo>(); 429 430 return vectorizeBB(BB); 431 } 432 433 virtual void getAnalysisUsage(AnalysisUsage &AU) const { 434 BasicBlockPass::getAnalysisUsage(AU); 435 AU.addRequired<AliasAnalysis>(); 436 AU.addRequired<DominatorTree>(); 437 AU.addRequired<ScalarEvolution>(); 438 AU.addPreserved<AliasAnalysis>(); 439 AU.addPreserved<DominatorTree>(); 440 AU.addPreserved<ScalarEvolution>(); 441 AU.setPreservesCFG(); 442 } 443 444 static inline VectorType *getVecTypeForPair(Type *ElemTy, Type *Elem2Ty) { 445 assert(ElemTy->getScalarType() == Elem2Ty->getScalarType() && 446 "Cannot form vector from incompatible scalar types"); 447 Type *STy = ElemTy->getScalarType(); 448 449 unsigned numElem; 450 if (VectorType *VTy = dyn_cast<VectorType>(ElemTy)) { 451 numElem = VTy->getNumElements(); 452 } else { 453 numElem = 1; 454 } 455 456 if (VectorType *VTy = dyn_cast<VectorType>(Elem2Ty)) { 457 numElem += VTy->getNumElements(); 458 } else { 459 numElem += 1; 460 } 461 462 return VectorType::get(STy, numElem); 463 } 464 465 static inline void getInstructionTypes(Instruction *I, 466 Type *&T1, Type *&T2) { 467 if (isa<StoreInst>(I)) { 468 // For stores, it is the value type, not the pointer type that matters 469 // because the value is what will come from a vector register. 470 471 Value *IVal = cast<StoreInst>(I)->getValueOperand(); 472 T1 = IVal->getType(); 473 } else { 474 T1 = I->getType(); 475 } 476 477 if (I->isCast()) 478 T2 = cast<CastInst>(I)->getSrcTy(); 479 else 480 T2 = T1; 481 482 if (SelectInst *SI = dyn_cast<SelectInst>(I)) { 483 T2 = SI->getCondition()->getType(); 484 } else if (ShuffleVectorInst *SI = dyn_cast<ShuffleVectorInst>(I)) { 485 T2 = SI->getOperand(0)->getType(); 486 } else if (CmpInst *CI = dyn_cast<CmpInst>(I)) { 487 T2 = CI->getOperand(0)->getType(); 488 } 489 } 490 491 // Returns the weight associated with the provided value. A chain of 492 // candidate pairs has a length given by the sum of the weights of its 493 // members (one weight per pair; the weight of each member of the pair 494 // is assumed to be the same). This length is then compared to the 495 // chain-length threshold to determine if a given chain is significant 496 // enough to be vectorized. The length is also used in comparing 497 // candidate chains where longer chains are considered to be better. 498 // Note: when this function returns 0, the resulting instructions are 499 // not actually fused. 500 inline size_t getDepthFactor(Value *V) { 501 // InsertElement and ExtractElement have a depth factor of zero. This is 502 // for two reasons: First, they cannot be usefully fused. Second, because 503 // the pass generates a lot of these, they can confuse the simple metric 504 // used to compare the trees in the next iteration. Thus, giving them a 505 // weight of zero allows the pass to essentially ignore them in 506 // subsequent iterations when looking for vectorization opportunities 507 // while still tracking dependency chains that flow through those 508 // instructions. 509 if (isa<InsertElementInst>(V) || isa<ExtractElementInst>(V)) 510 return 0; 511 512 // Give a load or store half of the required depth so that load/store 513 // pairs will vectorize. 514 if (!Config.NoMemOpBoost && (isa<LoadInst>(V) || isa<StoreInst>(V))) 515 return Config.ReqChainDepth/2; 516 517 return 1; 518 } 519 520 // Returns the cost of the provided instruction using TTI. 521 // This does not handle loads and stores. 522 unsigned getInstrCost(unsigned Opcode, Type *T1, Type *T2) { 523 switch (Opcode) { 524 default: break; 525 case Instruction::GetElementPtr: 526 // We mark this instruction as zero-cost because scalar GEPs are usually 527 // lowered to the intruction addressing mode. At the moment we don't 528 // generate vector GEPs. 529 return 0; 530 case Instruction::Br: 531 return TTI->getCFInstrCost(Opcode); 532 case Instruction::PHI: 533 return 0; 534 case Instruction::Add: 535 case Instruction::FAdd: 536 case Instruction::Sub: 537 case Instruction::FSub: 538 case Instruction::Mul: 539 case Instruction::FMul: 540 case Instruction::UDiv: 541 case Instruction::SDiv: 542 case Instruction::FDiv: 543 case Instruction::URem: 544 case Instruction::SRem: 545 case Instruction::FRem: 546 case Instruction::Shl: 547 case Instruction::LShr: 548 case Instruction::AShr: 549 case Instruction::And: 550 case Instruction::Or: 551 case Instruction::Xor: 552 return TTI->getArithmeticInstrCost(Opcode, T1); 553 case Instruction::Select: 554 case Instruction::ICmp: 555 case Instruction::FCmp: 556 return TTI->getCmpSelInstrCost(Opcode, T1, T2); 557 case Instruction::ZExt: 558 case Instruction::SExt: 559 case Instruction::FPToUI: 560 case Instruction::FPToSI: 561 case Instruction::FPExt: 562 case Instruction::PtrToInt: 563 case Instruction::IntToPtr: 564 case Instruction::SIToFP: 565 case Instruction::UIToFP: 566 case Instruction::Trunc: 567 case Instruction::FPTrunc: 568 case Instruction::BitCast: 569 case Instruction::ShuffleVector: 570 return TTI->getCastInstrCost(Opcode, T1, T2); 571 } 572 573 return 1; 574 } 575 576 // This determines the relative offset of two loads or stores, returning 577 // true if the offset could be determined to be some constant value. 578 // For example, if OffsetInElmts == 1, then J accesses the memory directly 579 // after I; if OffsetInElmts == -1 then I accesses the memory 580 // directly after J. 581 bool getPairPtrInfo(Instruction *I, Instruction *J, 582 Value *&IPtr, Value *&JPtr, unsigned &IAlignment, unsigned &JAlignment, 583 unsigned &IAddressSpace, unsigned &JAddressSpace, 584 int64_t &OffsetInElmts, bool ComputeOffset = true) { 585 OffsetInElmts = 0; 586 if (LoadInst *LI = dyn_cast<LoadInst>(I)) { 587 LoadInst *LJ = cast<LoadInst>(J); 588 IPtr = LI->getPointerOperand(); 589 JPtr = LJ->getPointerOperand(); 590 IAlignment = LI->getAlignment(); 591 JAlignment = LJ->getAlignment(); 592 IAddressSpace = LI->getPointerAddressSpace(); 593 JAddressSpace = LJ->getPointerAddressSpace(); 594 } else { 595 StoreInst *SI = cast<StoreInst>(I), *SJ = cast<StoreInst>(J); 596 IPtr = SI->getPointerOperand(); 597 JPtr = SJ->getPointerOperand(); 598 IAlignment = SI->getAlignment(); 599 JAlignment = SJ->getAlignment(); 600 IAddressSpace = SI->getPointerAddressSpace(); 601 JAddressSpace = SJ->getPointerAddressSpace(); 602 } 603 604 if (!ComputeOffset) 605 return true; 606 607 const SCEV *IPtrSCEV = SE->getSCEV(IPtr); 608 const SCEV *JPtrSCEV = SE->getSCEV(JPtr); 609 610 // If this is a trivial offset, then we'll get something like 611 // 1*sizeof(type). With target data, which we need anyway, this will get 612 // constant folded into a number. 613 const SCEV *OffsetSCEV = SE->getMinusSCEV(JPtrSCEV, IPtrSCEV); 614 if (const SCEVConstant *ConstOffSCEV = 615 dyn_cast<SCEVConstant>(OffsetSCEV)) { 616 ConstantInt *IntOff = ConstOffSCEV->getValue(); 617 int64_t Offset = IntOff->getSExtValue(); 618 619 Type *VTy = cast<PointerType>(IPtr->getType())->getElementType(); 620 int64_t VTyTSS = (int64_t) TD->getTypeStoreSize(VTy); 621 622 Type *VTy2 = cast<PointerType>(JPtr->getType())->getElementType(); 623 if (VTy != VTy2 && Offset < 0) { 624 int64_t VTy2TSS = (int64_t) TD->getTypeStoreSize(VTy2); 625 OffsetInElmts = Offset/VTy2TSS; 626 return (abs64(Offset) % VTy2TSS) == 0; 627 } 628 629 OffsetInElmts = Offset/VTyTSS; 630 return (abs64(Offset) % VTyTSS) == 0; 631 } 632 633 return false; 634 } 635 636 // Returns true if the provided CallInst represents an intrinsic that can 637 // be vectorized. 638 bool isVectorizableIntrinsic(CallInst* I) { 639 Function *F = I->getCalledFunction(); 640 if (!F) return false; 641 642 Intrinsic::ID IID = (Intrinsic::ID) F->getIntrinsicID(); 643 if (!IID) return false; 644 645 switch(IID) { 646 default: 647 return false; 648 case Intrinsic::sqrt: 649 case Intrinsic::powi: 650 case Intrinsic::sin: 651 case Intrinsic::cos: 652 case Intrinsic::log: 653 case Intrinsic::log2: 654 case Intrinsic::log10: 655 case Intrinsic::exp: 656 case Intrinsic::exp2: 657 case Intrinsic::pow: 658 return Config.VectorizeMath; 659 case Intrinsic::fma: 660 case Intrinsic::fmuladd: 661 return Config.VectorizeFMA; 662 } 663 } 664 665 // Returns true if J is the second element in some pair referenced by 666 // some multimap pair iterator pair. 667 template <typename V> 668 bool isSecondInIteratorPair(V J, std::pair< 669 typename std::multimap<V, V>::iterator, 670 typename std::multimap<V, V>::iterator> PairRange) { 671 for (typename std::multimap<V, V>::iterator K = PairRange.first; 672 K != PairRange.second; ++K) 673 if (K->second == J) return true; 674 675 return false; 676 } 677 678 bool isPureIEChain(InsertElementInst *IE) { 679 InsertElementInst *IENext = IE; 680 do { 681 if (!isa<UndefValue>(IENext->getOperand(0)) && 682 !isa<InsertElementInst>(IENext->getOperand(0))) { 683 return false; 684 } 685 } while ((IENext = 686 dyn_cast<InsertElementInst>(IENext->getOperand(0)))); 687 688 return true; 689 } 690 }; 691 692 // This function implements one vectorization iteration on the provided 693 // basic block. It returns true if the block is changed. 694 bool BBVectorize::vectorizePairs(BasicBlock &BB, bool NonPow2Len) { 695 bool ShouldContinue; 696 BasicBlock::iterator Start = BB.getFirstInsertionPt(); 697 698 std::vector<Value *> AllPairableInsts; 699 DenseMap<Value *, Value *> AllChosenPairs; 700 DenseSet<ValuePair> AllFixedOrderPairs; 701 DenseMap<VPPair, unsigned> AllPairConnectionTypes; 702 std::multimap<ValuePair, ValuePair> AllConnectedPairs, AllConnectedPairDeps; 703 704 do { 705 std::vector<Value *> PairableInsts; 706 std::multimap<Value *, Value *> CandidatePairs; 707 DenseSet<ValuePair> FixedOrderPairs; 708 DenseMap<ValuePair, int> CandidatePairCostSavings; 709 ShouldContinue = getCandidatePairs(BB, Start, CandidatePairs, 710 FixedOrderPairs, 711 CandidatePairCostSavings, 712 PairableInsts, NonPow2Len); 713 if (PairableInsts.empty()) continue; 714 715 // Now we have a map of all of the pairable instructions and we need to 716 // select the best possible pairing. A good pairing is one such that the 717 // users of the pair are also paired. This defines a (directed) forest 718 // over the pairs such that two pairs are connected iff the second pair 719 // uses the first. 720 721 // Note that it only matters that both members of the second pair use some 722 // element of the first pair (to allow for splatting). 723 724 std::multimap<ValuePair, ValuePair> ConnectedPairs, ConnectedPairDeps; 725 DenseMap<VPPair, unsigned> PairConnectionTypes; 726 computeConnectedPairs(CandidatePairs, PairableInsts, ConnectedPairs, 727 PairConnectionTypes); 728 if (ConnectedPairs.empty()) continue; 729 730 for (std::multimap<ValuePair, ValuePair>::iterator 731 I = ConnectedPairs.begin(), IE = ConnectedPairs.end(); 732 I != IE; ++I) { 733 ConnectedPairDeps.insert(VPPair(I->second, I->first)); 734 } 735 736 // Build the pairable-instruction dependency map 737 DenseSet<ValuePair> PairableInstUsers; 738 buildDepMap(BB, CandidatePairs, PairableInsts, PairableInstUsers); 739 740 // There is now a graph of the connected pairs. For each variable, pick 741 // the pairing with the largest tree meeting the depth requirement on at 742 // least one branch. Then select all pairings that are part of that tree 743 // and remove them from the list of available pairings and pairable 744 // variables. 745 746 DenseMap<Value *, Value *> ChosenPairs; 747 choosePairs(CandidatePairs, CandidatePairCostSavings, 748 PairableInsts, FixedOrderPairs, PairConnectionTypes, 749 ConnectedPairs, ConnectedPairDeps, 750 PairableInstUsers, ChosenPairs); 751 752 if (ChosenPairs.empty()) continue; 753 AllPairableInsts.insert(AllPairableInsts.end(), PairableInsts.begin(), 754 PairableInsts.end()); 755 AllChosenPairs.insert(ChosenPairs.begin(), ChosenPairs.end()); 756 757 // Only for the chosen pairs, propagate information on fixed-order pairs, 758 // pair connections, and their types to the data structures used by the 759 // pair fusion procedures. 760 for (DenseMap<Value *, Value *>::iterator I = ChosenPairs.begin(), 761 IE = ChosenPairs.end(); I != IE; ++I) { 762 if (FixedOrderPairs.count(*I)) 763 AllFixedOrderPairs.insert(*I); 764 else if (FixedOrderPairs.count(ValuePair(I->second, I->first))) 765 AllFixedOrderPairs.insert(ValuePair(I->second, I->first)); 766 767 for (DenseMap<Value *, Value *>::iterator J = ChosenPairs.begin(); 768 J != IE; ++J) { 769 DenseMap<VPPair, unsigned>::iterator K = 770 PairConnectionTypes.find(VPPair(*I, *J)); 771 if (K != PairConnectionTypes.end()) { 772 AllPairConnectionTypes.insert(*K); 773 } else { 774 K = PairConnectionTypes.find(VPPair(*J, *I)); 775 if (K != PairConnectionTypes.end()) 776 AllPairConnectionTypes.insert(*K); 777 } 778 } 779 } 780 781 for (std::multimap<ValuePair, ValuePair>::iterator 782 I = ConnectedPairs.begin(), IE = ConnectedPairs.end(); 783 I != IE; ++I) { 784 if (AllPairConnectionTypes.count(*I)) { 785 AllConnectedPairs.insert(*I); 786 AllConnectedPairDeps.insert(VPPair(I->second, I->first)); 787 } 788 } 789 } while (ShouldContinue); 790 791 if (AllChosenPairs.empty()) return false; 792 NumFusedOps += AllChosenPairs.size(); 793 794 // A set of pairs has now been selected. It is now necessary to replace the 795 // paired instructions with vector instructions. For this procedure each 796 // operand must be replaced with a vector operand. This vector is formed 797 // by using build_vector on the old operands. The replaced values are then 798 // replaced with a vector_extract on the result. Subsequent optimization 799 // passes should coalesce the build/extract combinations. 800 801 fuseChosenPairs(BB, AllPairableInsts, AllChosenPairs, AllFixedOrderPairs, 802 AllPairConnectionTypes, 803 AllConnectedPairs, AllConnectedPairDeps); 804 805 // It is important to cleanup here so that future iterations of this 806 // function have less work to do. 807 (void) SimplifyInstructionsInBlock(&BB, TD, AA->getTargetLibraryInfo()); 808 return true; 809 } 810 811 // This function returns true if the provided instruction is capable of being 812 // fused into a vector instruction. This determination is based only on the 813 // type and other attributes of the instruction. 814 bool BBVectorize::isInstVectorizable(Instruction *I, 815 bool &IsSimpleLoadStore) { 816 IsSimpleLoadStore = false; 817 818 if (CallInst *C = dyn_cast<CallInst>(I)) { 819 if (!isVectorizableIntrinsic(C)) 820 return false; 821 } else if (LoadInst *L = dyn_cast<LoadInst>(I)) { 822 // Vectorize simple loads if possbile: 823 IsSimpleLoadStore = L->isSimple(); 824 if (!IsSimpleLoadStore || !Config.VectorizeMemOps) 825 return false; 826 } else if (StoreInst *S = dyn_cast<StoreInst>(I)) { 827 // Vectorize simple stores if possbile: 828 IsSimpleLoadStore = S->isSimple(); 829 if (!IsSimpleLoadStore || !Config.VectorizeMemOps) 830 return false; 831 } else if (CastInst *C = dyn_cast<CastInst>(I)) { 832 // We can vectorize casts, but not casts of pointer types, etc. 833 if (!Config.VectorizeCasts) 834 return false; 835 836 Type *SrcTy = C->getSrcTy(); 837 if (!SrcTy->isSingleValueType()) 838 return false; 839 840 Type *DestTy = C->getDestTy(); 841 if (!DestTy->isSingleValueType()) 842 return false; 843 } else if (isa<SelectInst>(I)) { 844 if (!Config.VectorizeSelect) 845 return false; 846 } else if (isa<CmpInst>(I)) { 847 if (!Config.VectorizeCmp) 848 return false; 849 } else if (GetElementPtrInst *G = dyn_cast<GetElementPtrInst>(I)) { 850 if (!Config.VectorizeGEP) 851 return false; 852 853 // Currently, vector GEPs exist only with one index. 854 if (G->getNumIndices() != 1) 855 return false; 856 } else if (!(I->isBinaryOp() || isa<ShuffleVectorInst>(I) || 857 isa<ExtractElementInst>(I) || isa<InsertElementInst>(I))) { 858 return false; 859 } 860 861 // We can't vectorize memory operations without target data 862 if (TD == 0 && IsSimpleLoadStore) 863 return false; 864 865 Type *T1, *T2; 866 getInstructionTypes(I, T1, T2); 867 868 // Not every type can be vectorized... 869 if (!(VectorType::isValidElementType(T1) || T1->isVectorTy()) || 870 !(VectorType::isValidElementType(T2) || T2->isVectorTy())) 871 return false; 872 873 if (T1->getScalarSizeInBits() == 1) { 874 if (!Config.VectorizeBools) 875 return false; 876 } else { 877 if (!Config.VectorizeInts && T1->isIntOrIntVectorTy()) 878 return false; 879 } 880 881 if (T2->getScalarSizeInBits() == 1) { 882 if (!Config.VectorizeBools) 883 return false; 884 } else { 885 if (!Config.VectorizeInts && T2->isIntOrIntVectorTy()) 886 return false; 887 } 888 889 if (!Config.VectorizeFloats 890 && (T1->isFPOrFPVectorTy() || T2->isFPOrFPVectorTy())) 891 return false; 892 893 // Don't vectorize target-specific types. 894 if (T1->isX86_FP80Ty() || T1->isPPC_FP128Ty() || T1->isX86_MMXTy()) 895 return false; 896 if (T2->isX86_FP80Ty() || T2->isPPC_FP128Ty() || T2->isX86_MMXTy()) 897 return false; 898 899 if ((!Config.VectorizePointers || TD == 0) && 900 (T1->getScalarType()->isPointerTy() || 901 T2->getScalarType()->isPointerTy())) 902 return false; 903 904 if (!TTI && (T1->getPrimitiveSizeInBits() >= Config.VectorBits || 905 T2->getPrimitiveSizeInBits() >= Config.VectorBits)) 906 return false; 907 908 return true; 909 } 910 911 // This function returns true if the two provided instructions are compatible 912 // (meaning that they can be fused into a vector instruction). This assumes 913 // that I has already been determined to be vectorizable and that J is not 914 // in the use tree of I. 915 bool BBVectorize::areInstsCompatible(Instruction *I, Instruction *J, 916 bool IsSimpleLoadStore, bool NonPow2Len, 917 int &CostSavings, int &FixedOrder) { 918 DEBUG(if (DebugInstructionExamination) dbgs() << "BBV: looking at " << *I << 919 " <-> " << *J << "\n"); 920 921 CostSavings = 0; 922 FixedOrder = 0; 923 924 // Loads and stores can be merged if they have different alignments, 925 // but are otherwise the same. 926 if (!J->isSameOperationAs(I, Instruction::CompareIgnoringAlignment | 927 (NonPow2Len ? Instruction::CompareUsingScalarTypes : 0))) 928 return false; 929 930 Type *IT1, *IT2, *JT1, *JT2; 931 getInstructionTypes(I, IT1, IT2); 932 getInstructionTypes(J, JT1, JT2); 933 unsigned MaxTypeBits = std::max( 934 IT1->getPrimitiveSizeInBits() + JT1->getPrimitiveSizeInBits(), 935 IT2->getPrimitiveSizeInBits() + JT2->getPrimitiveSizeInBits()); 936 if (!TTI && MaxTypeBits > Config.VectorBits) 937 return false; 938 939 // FIXME: handle addsub-type operations! 940 941 if (IsSimpleLoadStore) { 942 Value *IPtr, *JPtr; 943 unsigned IAlignment, JAlignment, IAddressSpace, JAddressSpace; 944 int64_t OffsetInElmts = 0; 945 if (getPairPtrInfo(I, J, IPtr, JPtr, IAlignment, JAlignment, 946 IAddressSpace, JAddressSpace, 947 OffsetInElmts) && abs64(OffsetInElmts) == 1) { 948 FixedOrder = (int) OffsetInElmts; 949 unsigned BottomAlignment = IAlignment; 950 if (OffsetInElmts < 0) BottomAlignment = JAlignment; 951 952 Type *aTypeI = isa<StoreInst>(I) ? 953 cast<StoreInst>(I)->getValueOperand()->getType() : I->getType(); 954 Type *aTypeJ = isa<StoreInst>(J) ? 955 cast<StoreInst>(J)->getValueOperand()->getType() : J->getType(); 956 Type *VType = getVecTypeForPair(aTypeI, aTypeJ); 957 958 if (Config.AlignedOnly) { 959 // An aligned load or store is possible only if the instruction 960 // with the lower offset has an alignment suitable for the 961 // vector type. 962 963 unsigned VecAlignment = TD->getPrefTypeAlignment(VType); 964 if (BottomAlignment < VecAlignment) 965 return false; 966 } 967 968 if (TTI) { 969 unsigned ICost = TTI->getMemoryOpCost(I->getOpcode(), aTypeI, 970 IAlignment, IAddressSpace); 971 unsigned JCost = TTI->getMemoryOpCost(J->getOpcode(), aTypeJ, 972 JAlignment, JAddressSpace); 973 unsigned VCost = TTI->getMemoryOpCost(I->getOpcode(), VType, 974 BottomAlignment, 975 IAddressSpace); 976 if (VCost > ICost + JCost) 977 return false; 978 979 // We don't want to fuse to a type that will be split, even 980 // if the two input types will also be split and there is no other 981 // associated cost. 982 unsigned VParts = TTI->getNumberOfParts(VType); 983 if (VParts > 1) 984 return false; 985 else if (!VParts && VCost == ICost + JCost) 986 return false; 987 988 CostSavings = ICost + JCost - VCost; 989 } 990 } else { 991 return false; 992 } 993 } else if (TTI) { 994 unsigned ICost = getInstrCost(I->getOpcode(), IT1, IT2); 995 unsigned JCost = getInstrCost(J->getOpcode(), JT1, JT2); 996 Type *VT1 = getVecTypeForPair(IT1, JT1), 997 *VT2 = getVecTypeForPair(IT2, JT2); 998 unsigned VCost = getInstrCost(I->getOpcode(), VT1, VT2); 999 1000 if (VCost > ICost + JCost) 1001 return false; 1002 1003 // We don't want to fuse to a type that will be split, even 1004 // if the two input types will also be split and there is no other 1005 // associated cost. 1006 unsigned VParts1 = TTI->getNumberOfParts(VT1), 1007 VParts2 = TTI->getNumberOfParts(VT2); 1008 if (VParts1 > 1 || VParts2 > 1) 1009 return false; 1010 else if ((!VParts1 || !VParts2) && VCost == ICost + JCost) 1011 return false; 1012 1013 CostSavings = ICost + JCost - VCost; 1014 } 1015 1016 // The powi intrinsic is special because only the first argument is 1017 // vectorized, the second arguments must be equal. 1018 CallInst *CI = dyn_cast<CallInst>(I); 1019 Function *FI; 1020 if (CI && (FI = CI->getCalledFunction())) { 1021 Intrinsic::ID IID = (Intrinsic::ID) FI->getIntrinsicID(); 1022 if (IID == Intrinsic::powi) { 1023 Value *A1I = CI->getArgOperand(1), 1024 *A1J = cast<CallInst>(J)->getArgOperand(1); 1025 const SCEV *A1ISCEV = SE->getSCEV(A1I), 1026 *A1JSCEV = SE->getSCEV(A1J); 1027 return (A1ISCEV == A1JSCEV); 1028 } 1029 1030 if (IID && TTI) { 1031 SmallVector<Type*, 4> Tys; 1032 for (unsigned i = 0, ie = CI->getNumArgOperands(); i != ie; ++i) 1033 Tys.push_back(CI->getArgOperand(i)->getType()); 1034 unsigned ICost = TTI->getIntrinsicInstrCost(IID, IT1, Tys); 1035 1036 Tys.clear(); 1037 CallInst *CJ = cast<CallInst>(J); 1038 for (unsigned i = 0, ie = CJ->getNumArgOperands(); i != ie; ++i) 1039 Tys.push_back(CJ->getArgOperand(i)->getType()); 1040 unsigned JCost = TTI->getIntrinsicInstrCost(IID, JT1, Tys); 1041 1042 Tys.clear(); 1043 assert(CI->getNumArgOperands() == CJ->getNumArgOperands() && 1044 "Intrinsic argument counts differ"); 1045 for (unsigned i = 0, ie = CI->getNumArgOperands(); i != ie; ++i) { 1046 if (IID == Intrinsic::powi && i == 1) 1047 Tys.push_back(CI->getArgOperand(i)->getType()); 1048 else 1049 Tys.push_back(getVecTypeForPair(CI->getArgOperand(i)->getType(), 1050 CJ->getArgOperand(i)->getType())); 1051 } 1052 1053 Type *RetTy = getVecTypeForPair(IT1, JT1); 1054 unsigned VCost = TTI->getIntrinsicInstrCost(IID, RetTy, Tys); 1055 1056 if (VCost > ICost + JCost) 1057 return false; 1058 1059 // We don't want to fuse to a type that will be split, even 1060 // if the two input types will also be split and there is no other 1061 // associated cost. 1062 unsigned RetParts = TTI->getNumberOfParts(RetTy); 1063 if (RetParts > 1) 1064 return false; 1065 else if (!RetParts && VCost == ICost + JCost) 1066 return false; 1067 1068 for (unsigned i = 0, ie = CI->getNumArgOperands(); i != ie; ++i) { 1069 if (!Tys[i]->isVectorTy()) 1070 continue; 1071 1072 unsigned NumParts = TTI->getNumberOfParts(Tys[i]); 1073 if (NumParts > 1) 1074 return false; 1075 else if (!NumParts && VCost == ICost + JCost) 1076 return false; 1077 } 1078 1079 CostSavings = ICost + JCost - VCost; 1080 } 1081 } 1082 1083 return true; 1084 } 1085 1086 // Figure out whether or not J uses I and update the users and write-set 1087 // structures associated with I. Specifically, Users represents the set of 1088 // instructions that depend on I. WriteSet represents the set 1089 // of memory locations that are dependent on I. If UpdateUsers is true, 1090 // and J uses I, then Users is updated to contain J and WriteSet is updated 1091 // to contain any memory locations to which J writes. The function returns 1092 // true if J uses I. By default, alias analysis is used to determine 1093 // whether J reads from memory that overlaps with a location in WriteSet. 1094 // If LoadMoveSet is not null, then it is a previously-computed multimap 1095 // where the key is the memory-based user instruction and the value is 1096 // the instruction to be compared with I. So, if LoadMoveSet is provided, 1097 // then the alias analysis is not used. This is necessary because this 1098 // function is called during the process of moving instructions during 1099 // vectorization and the results of the alias analysis are not stable during 1100 // that process. 1101 bool BBVectorize::trackUsesOfI(DenseSet<Value *> &Users, 1102 AliasSetTracker &WriteSet, Instruction *I, 1103 Instruction *J, bool UpdateUsers, 1104 std::multimap<Value *, Value *> *LoadMoveSet) { 1105 bool UsesI = false; 1106 1107 // This instruction may already be marked as a user due, for example, to 1108 // being a member of a selected pair. 1109 if (Users.count(J)) 1110 UsesI = true; 1111 1112 if (!UsesI) 1113 for (User::op_iterator JU = J->op_begin(), JE = J->op_end(); 1114 JU != JE; ++JU) { 1115 Value *V = *JU; 1116 if (I == V || Users.count(V)) { 1117 UsesI = true; 1118 break; 1119 } 1120 } 1121 if (!UsesI && J->mayReadFromMemory()) { 1122 if (LoadMoveSet) { 1123 VPIteratorPair JPairRange = LoadMoveSet->equal_range(J); 1124 UsesI = isSecondInIteratorPair<Value*>(I, JPairRange); 1125 } else { 1126 for (AliasSetTracker::iterator W = WriteSet.begin(), 1127 WE = WriteSet.end(); W != WE; ++W) { 1128 if (W->aliasesUnknownInst(J, *AA)) { 1129 UsesI = true; 1130 break; 1131 } 1132 } 1133 } 1134 } 1135 1136 if (UsesI && UpdateUsers) { 1137 if (J->mayWriteToMemory()) WriteSet.add(J); 1138 Users.insert(J); 1139 } 1140 1141 return UsesI; 1142 } 1143 1144 // This function iterates over all instruction pairs in the provided 1145 // basic block and collects all candidate pairs for vectorization. 1146 bool BBVectorize::getCandidatePairs(BasicBlock &BB, 1147 BasicBlock::iterator &Start, 1148 std::multimap<Value *, Value *> &CandidatePairs, 1149 DenseSet<ValuePair> &FixedOrderPairs, 1150 DenseMap<ValuePair, int> &CandidatePairCostSavings, 1151 std::vector<Value *> &PairableInsts, bool NonPow2Len) { 1152 BasicBlock::iterator E = BB.end(); 1153 if (Start == E) return false; 1154 1155 bool ShouldContinue = false, IAfterStart = false; 1156 for (BasicBlock::iterator I = Start++; I != E; ++I) { 1157 if (I == Start) IAfterStart = true; 1158 1159 bool IsSimpleLoadStore; 1160 if (!isInstVectorizable(I, IsSimpleLoadStore)) continue; 1161 1162 // Look for an instruction with which to pair instruction *I... 1163 DenseSet<Value *> Users; 1164 AliasSetTracker WriteSet(*AA); 1165 bool JAfterStart = IAfterStart; 1166 BasicBlock::iterator J = llvm::next(I); 1167 for (unsigned ss = 0; J != E && ss <= Config.SearchLimit; ++J, ++ss) { 1168 if (J == Start) JAfterStart = true; 1169 1170 // Determine if J uses I, if so, exit the loop. 1171 bool UsesI = trackUsesOfI(Users, WriteSet, I, J, !Config.FastDep); 1172 if (Config.FastDep) { 1173 // Note: For this heuristic to be effective, independent operations 1174 // must tend to be intermixed. This is likely to be true from some 1175 // kinds of grouped loop unrolling (but not the generic LLVM pass), 1176 // but otherwise may require some kind of reordering pass. 1177 1178 // When using fast dependency analysis, 1179 // stop searching after first use: 1180 if (UsesI) break; 1181 } else { 1182 if (UsesI) continue; 1183 } 1184 1185 // J does not use I, and comes before the first use of I, so it can be 1186 // merged with I if the instructions are compatible. 1187 int CostSavings, FixedOrder; 1188 if (!areInstsCompatible(I, J, IsSimpleLoadStore, NonPow2Len, 1189 CostSavings, FixedOrder)) continue; 1190 1191 // J is a candidate for merging with I. 1192 if (!PairableInsts.size() || 1193 PairableInsts[PairableInsts.size()-1] != I) { 1194 PairableInsts.push_back(I); 1195 } 1196 1197 CandidatePairs.insert(ValuePair(I, J)); 1198 if (TTI) 1199 CandidatePairCostSavings.insert(ValuePairWithCost(ValuePair(I, J), 1200 CostSavings)); 1201 1202 if (FixedOrder == 1) 1203 FixedOrderPairs.insert(ValuePair(I, J)); 1204 else if (FixedOrder == -1) 1205 FixedOrderPairs.insert(ValuePair(J, I)); 1206 1207 // The next call to this function must start after the last instruction 1208 // selected during this invocation. 1209 if (JAfterStart) { 1210 Start = llvm::next(J); 1211 IAfterStart = JAfterStart = false; 1212 } 1213 1214 DEBUG(if (DebugCandidateSelection) dbgs() << "BBV: candidate pair " 1215 << *I << " <-> " << *J << " (cost savings: " << 1216 CostSavings << ")\n"); 1217 1218 // If we have already found too many pairs, break here and this function 1219 // will be called again starting after the last instruction selected 1220 // during this invocation. 1221 if (PairableInsts.size() >= Config.MaxInsts) { 1222 ShouldContinue = true; 1223 break; 1224 } 1225 } 1226 1227 if (ShouldContinue) 1228 break; 1229 } 1230 1231 DEBUG(dbgs() << "BBV: found " << PairableInsts.size() 1232 << " instructions with candidate pairs\n"); 1233 1234 return ShouldContinue; 1235 } 1236 1237 // Finds candidate pairs connected to the pair P = <PI, PJ>. This means that 1238 // it looks for pairs such that both members have an input which is an 1239 // output of PI or PJ. 1240 void BBVectorize::computePairsConnectedTo( 1241 std::multimap<Value *, Value *> &CandidatePairs, 1242 std::vector<Value *> &PairableInsts, 1243 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 1244 DenseMap<VPPair, unsigned> &PairConnectionTypes, 1245 ValuePair P) { 1246 StoreInst *SI, *SJ; 1247 1248 // For each possible pairing for this variable, look at the uses of 1249 // the first value... 1250 for (Value::use_iterator I = P.first->use_begin(), 1251 E = P.first->use_end(); I != E; ++I) { 1252 if (isa<LoadInst>(*I)) { 1253 // A pair cannot be connected to a load because the load only takes one 1254 // operand (the address) and it is a scalar even after vectorization. 1255 continue; 1256 } else if ((SI = dyn_cast<StoreInst>(*I)) && 1257 P.first == SI->getPointerOperand()) { 1258 // Similarly, a pair cannot be connected to a store through its 1259 // pointer operand. 1260 continue; 1261 } 1262 1263 VPIteratorPair IPairRange = CandidatePairs.equal_range(*I); 1264 1265 // For each use of the first variable, look for uses of the second 1266 // variable... 1267 for (Value::use_iterator J = P.second->use_begin(), 1268 E2 = P.second->use_end(); J != E2; ++J) { 1269 if ((SJ = dyn_cast<StoreInst>(*J)) && 1270 P.second == SJ->getPointerOperand()) 1271 continue; 1272 1273 VPIteratorPair JPairRange = CandidatePairs.equal_range(*J); 1274 1275 // Look for <I, J>: 1276 if (isSecondInIteratorPair<Value*>(*J, IPairRange)) { 1277 VPPair VP(P, ValuePair(*I, *J)); 1278 ConnectedPairs.insert(VP); 1279 PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionDirect)); 1280 } 1281 1282 // Look for <J, I>: 1283 if (isSecondInIteratorPair<Value*>(*I, JPairRange)) { 1284 VPPair VP(P, ValuePair(*J, *I)); 1285 ConnectedPairs.insert(VP); 1286 PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionSwap)); 1287 } 1288 } 1289 1290 if (Config.SplatBreaksChain) continue; 1291 // Look for cases where just the first value in the pair is used by 1292 // both members of another pair (splatting). 1293 for (Value::use_iterator J = P.first->use_begin(); J != E; ++J) { 1294 if ((SJ = dyn_cast<StoreInst>(*J)) && 1295 P.first == SJ->getPointerOperand()) 1296 continue; 1297 1298 if (isSecondInIteratorPair<Value*>(*J, IPairRange)) { 1299 VPPair VP(P, ValuePair(*I, *J)); 1300 ConnectedPairs.insert(VP); 1301 PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionSplat)); 1302 } 1303 } 1304 } 1305 1306 if (Config.SplatBreaksChain) return; 1307 // Look for cases where just the second value in the pair is used by 1308 // both members of another pair (splatting). 1309 for (Value::use_iterator I = P.second->use_begin(), 1310 E = P.second->use_end(); I != E; ++I) { 1311 if (isa<LoadInst>(*I)) 1312 continue; 1313 else if ((SI = dyn_cast<StoreInst>(*I)) && 1314 P.second == SI->getPointerOperand()) 1315 continue; 1316 1317 VPIteratorPair IPairRange = CandidatePairs.equal_range(*I); 1318 1319 for (Value::use_iterator J = P.second->use_begin(); J != E; ++J) { 1320 if ((SJ = dyn_cast<StoreInst>(*J)) && 1321 P.second == SJ->getPointerOperand()) 1322 continue; 1323 1324 if (isSecondInIteratorPair<Value*>(*J, IPairRange)) { 1325 VPPair VP(P, ValuePair(*I, *J)); 1326 ConnectedPairs.insert(VP); 1327 PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionSplat)); 1328 } 1329 } 1330 } 1331 } 1332 1333 // This function figures out which pairs are connected. Two pairs are 1334 // connected if some output of the first pair forms an input to both members 1335 // of the second pair. 1336 void BBVectorize::computeConnectedPairs( 1337 std::multimap<Value *, Value *> &CandidatePairs, 1338 std::vector<Value *> &PairableInsts, 1339 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 1340 DenseMap<VPPair, unsigned> &PairConnectionTypes) { 1341 1342 for (std::vector<Value *>::iterator PI = PairableInsts.begin(), 1343 PE = PairableInsts.end(); PI != PE; ++PI) { 1344 VPIteratorPair choiceRange = CandidatePairs.equal_range(*PI); 1345 1346 for (std::multimap<Value *, Value *>::iterator P = choiceRange.first; 1347 P != choiceRange.second; ++P) 1348 computePairsConnectedTo(CandidatePairs, PairableInsts, 1349 ConnectedPairs, PairConnectionTypes, *P); 1350 } 1351 1352 DEBUG(dbgs() << "BBV: found " << ConnectedPairs.size() 1353 << " pair connections.\n"); 1354 } 1355 1356 // This function builds a set of use tuples such that <A, B> is in the set 1357 // if B is in the use tree of A. If B is in the use tree of A, then B 1358 // depends on the output of A. 1359 void BBVectorize::buildDepMap( 1360 BasicBlock &BB, 1361 std::multimap<Value *, Value *> &CandidatePairs, 1362 std::vector<Value *> &PairableInsts, 1363 DenseSet<ValuePair> &PairableInstUsers) { 1364 DenseSet<Value *> IsInPair; 1365 for (std::multimap<Value *, Value *>::iterator C = CandidatePairs.begin(), 1366 E = CandidatePairs.end(); C != E; ++C) { 1367 IsInPair.insert(C->first); 1368 IsInPair.insert(C->second); 1369 } 1370 1371 // Iterate through the basic block, recording all Users of each 1372 // pairable instruction. 1373 1374 BasicBlock::iterator E = BB.end(); 1375 for (BasicBlock::iterator I = BB.getFirstInsertionPt(); I != E; ++I) { 1376 if (IsInPair.find(I) == IsInPair.end()) continue; 1377 1378 DenseSet<Value *> Users; 1379 AliasSetTracker WriteSet(*AA); 1380 for (BasicBlock::iterator J = llvm::next(I); J != E; ++J) 1381 (void) trackUsesOfI(Users, WriteSet, I, J); 1382 1383 for (DenseSet<Value *>::iterator U = Users.begin(), E = Users.end(); 1384 U != E; ++U) 1385 PairableInstUsers.insert(ValuePair(I, *U)); 1386 } 1387 } 1388 1389 // Returns true if an input to pair P is an output of pair Q and also an 1390 // input of pair Q is an output of pair P. If this is the case, then these 1391 // two pairs cannot be simultaneously fused. 1392 bool BBVectorize::pairsConflict(ValuePair P, ValuePair Q, 1393 DenseSet<ValuePair> &PairableInstUsers, 1394 std::multimap<ValuePair, ValuePair> *PairableInstUserMap) { 1395 // Two pairs are in conflict if they are mutual Users of eachother. 1396 bool QUsesP = PairableInstUsers.count(ValuePair(P.first, Q.first)) || 1397 PairableInstUsers.count(ValuePair(P.first, Q.second)) || 1398 PairableInstUsers.count(ValuePair(P.second, Q.first)) || 1399 PairableInstUsers.count(ValuePair(P.second, Q.second)); 1400 bool PUsesQ = PairableInstUsers.count(ValuePair(Q.first, P.first)) || 1401 PairableInstUsers.count(ValuePair(Q.first, P.second)) || 1402 PairableInstUsers.count(ValuePair(Q.second, P.first)) || 1403 PairableInstUsers.count(ValuePair(Q.second, P.second)); 1404 if (PairableInstUserMap) { 1405 // FIXME: The expensive part of the cycle check is not so much the cycle 1406 // check itself but this edge insertion procedure. This needs some 1407 // profiling and probably a different data structure (same is true of 1408 // most uses of std::multimap). 1409 if (PUsesQ) { 1410 VPPIteratorPair QPairRange = PairableInstUserMap->equal_range(Q); 1411 if (!isSecondInIteratorPair(P, QPairRange)) 1412 PairableInstUserMap->insert(VPPair(Q, P)); 1413 } 1414 if (QUsesP) { 1415 VPPIteratorPair PPairRange = PairableInstUserMap->equal_range(P); 1416 if (!isSecondInIteratorPair(Q, PPairRange)) 1417 PairableInstUserMap->insert(VPPair(P, Q)); 1418 } 1419 } 1420 1421 return (QUsesP && PUsesQ); 1422 } 1423 1424 // This function walks the use graph of current pairs to see if, starting 1425 // from P, the walk returns to P. 1426 bool BBVectorize::pairWillFormCycle(ValuePair P, 1427 std::multimap<ValuePair, ValuePair> &PairableInstUserMap, 1428 DenseSet<ValuePair> &CurrentPairs) { 1429 DEBUG(if (DebugCycleCheck) 1430 dbgs() << "BBV: starting cycle check for : " << *P.first << " <-> " 1431 << *P.second << "\n"); 1432 // A lookup table of visisted pairs is kept because the PairableInstUserMap 1433 // contains non-direct associations. 1434 DenseSet<ValuePair> Visited; 1435 SmallVector<ValuePair, 32> Q; 1436 // General depth-first post-order traversal: 1437 Q.push_back(P); 1438 do { 1439 ValuePair QTop = Q.pop_back_val(); 1440 Visited.insert(QTop); 1441 1442 DEBUG(if (DebugCycleCheck) 1443 dbgs() << "BBV: cycle check visiting: " << *QTop.first << " <-> " 1444 << *QTop.second << "\n"); 1445 VPPIteratorPair QPairRange = PairableInstUserMap.equal_range(QTop); 1446 for (std::multimap<ValuePair, ValuePair>::iterator C = QPairRange.first; 1447 C != QPairRange.second; ++C) { 1448 if (C->second == P) { 1449 DEBUG(dbgs() 1450 << "BBV: rejected to prevent non-trivial cycle formation: " 1451 << *C->first.first << " <-> " << *C->first.second << "\n"); 1452 return true; 1453 } 1454 1455 if (CurrentPairs.count(C->second) && !Visited.count(C->second)) 1456 Q.push_back(C->second); 1457 } 1458 } while (!Q.empty()); 1459 1460 return false; 1461 } 1462 1463 // This function builds the initial tree of connected pairs with the 1464 // pair J at the root. 1465 void BBVectorize::buildInitialTreeFor( 1466 std::multimap<Value *, Value *> &CandidatePairs, 1467 std::vector<Value *> &PairableInsts, 1468 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 1469 DenseSet<ValuePair> &PairableInstUsers, 1470 DenseMap<Value *, Value *> &ChosenPairs, 1471 DenseMap<ValuePair, size_t> &Tree, ValuePair J) { 1472 // Each of these pairs is viewed as the root node of a Tree. The Tree 1473 // is then walked (depth-first). As this happens, we keep track of 1474 // the pairs that compose the Tree and the maximum depth of the Tree. 1475 SmallVector<ValuePairWithDepth, 32> Q; 1476 // General depth-first post-order traversal: 1477 Q.push_back(ValuePairWithDepth(J, getDepthFactor(J.first))); 1478 do { 1479 ValuePairWithDepth QTop = Q.back(); 1480 1481 // Push each child onto the queue: 1482 bool MoreChildren = false; 1483 size_t MaxChildDepth = QTop.second; 1484 VPPIteratorPair qtRange = ConnectedPairs.equal_range(QTop.first); 1485 for (std::multimap<ValuePair, ValuePair>::iterator k = qtRange.first; 1486 k != qtRange.second; ++k) { 1487 // Make sure that this child pair is still a candidate: 1488 bool IsStillCand = false; 1489 VPIteratorPair checkRange = 1490 CandidatePairs.equal_range(k->second.first); 1491 for (std::multimap<Value *, Value *>::iterator m = checkRange.first; 1492 m != checkRange.second; ++m) { 1493 if (m->second == k->second.second) { 1494 IsStillCand = true; 1495 break; 1496 } 1497 } 1498 1499 if (IsStillCand) { 1500 DenseMap<ValuePair, size_t>::iterator C = Tree.find(k->second); 1501 if (C == Tree.end()) { 1502 size_t d = getDepthFactor(k->second.first); 1503 Q.push_back(ValuePairWithDepth(k->second, QTop.second+d)); 1504 MoreChildren = true; 1505 } else { 1506 MaxChildDepth = std::max(MaxChildDepth, C->second); 1507 } 1508 } 1509 } 1510 1511 if (!MoreChildren) { 1512 // Record the current pair as part of the Tree: 1513 Tree.insert(ValuePairWithDepth(QTop.first, MaxChildDepth)); 1514 Q.pop_back(); 1515 } 1516 } while (!Q.empty()); 1517 } 1518 1519 // Given some initial tree, prune it by removing conflicting pairs (pairs 1520 // that cannot be simultaneously chosen for vectorization). 1521 void BBVectorize::pruneTreeFor( 1522 std::multimap<Value *, Value *> &CandidatePairs, 1523 std::vector<Value *> &PairableInsts, 1524 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 1525 DenseSet<ValuePair> &PairableInstUsers, 1526 std::multimap<ValuePair, ValuePair> &PairableInstUserMap, 1527 DenseMap<Value *, Value *> &ChosenPairs, 1528 DenseMap<ValuePair, size_t> &Tree, 1529 DenseSet<ValuePair> &PrunedTree, ValuePair J, 1530 bool UseCycleCheck) { 1531 SmallVector<ValuePairWithDepth, 32> Q; 1532 // General depth-first post-order traversal: 1533 Q.push_back(ValuePairWithDepth(J, getDepthFactor(J.first))); 1534 do { 1535 ValuePairWithDepth QTop = Q.pop_back_val(); 1536 PrunedTree.insert(QTop.first); 1537 1538 // Visit each child, pruning as necessary... 1539 SmallVector<ValuePairWithDepth, 8> BestChildren; 1540 VPPIteratorPair QTopRange = ConnectedPairs.equal_range(QTop.first); 1541 for (std::multimap<ValuePair, ValuePair>::iterator K = QTopRange.first; 1542 K != QTopRange.second; ++K) { 1543 DenseMap<ValuePair, size_t>::iterator C = Tree.find(K->second); 1544 if (C == Tree.end()) continue; 1545 1546 // This child is in the Tree, now we need to make sure it is the 1547 // best of any conflicting children. There could be multiple 1548 // conflicting children, so first, determine if we're keeping 1549 // this child, then delete conflicting children as necessary. 1550 1551 // It is also necessary to guard against pairing-induced 1552 // dependencies. Consider instructions a .. x .. y .. b 1553 // such that (a,b) are to be fused and (x,y) are to be fused 1554 // but a is an input to x and b is an output from y. This 1555 // means that y cannot be moved after b but x must be moved 1556 // after b for (a,b) to be fused. In other words, after 1557 // fusing (a,b) we have y .. a/b .. x where y is an input 1558 // to a/b and x is an output to a/b: x and y can no longer 1559 // be legally fused. To prevent this condition, we must 1560 // make sure that a child pair added to the Tree is not 1561 // both an input and output of an already-selected pair. 1562 1563 // Pairing-induced dependencies can also form from more complicated 1564 // cycles. The pair vs. pair conflicts are easy to check, and so 1565 // that is done explicitly for "fast rejection", and because for 1566 // child vs. child conflicts, we may prefer to keep the current 1567 // pair in preference to the already-selected child. 1568 DenseSet<ValuePair> CurrentPairs; 1569 1570 bool CanAdd = true; 1571 for (SmallVector<ValuePairWithDepth, 8>::iterator C2 1572 = BestChildren.begin(), E2 = BestChildren.end(); 1573 C2 != E2; ++C2) { 1574 if (C2->first.first == C->first.first || 1575 C2->first.first == C->first.second || 1576 C2->first.second == C->first.first || 1577 C2->first.second == C->first.second || 1578 pairsConflict(C2->first, C->first, PairableInstUsers, 1579 UseCycleCheck ? &PairableInstUserMap : 0)) { 1580 if (C2->second >= C->second) { 1581 CanAdd = false; 1582 break; 1583 } 1584 1585 CurrentPairs.insert(C2->first); 1586 } 1587 } 1588 if (!CanAdd) continue; 1589 1590 // Even worse, this child could conflict with another node already 1591 // selected for the Tree. If that is the case, ignore this child. 1592 for (DenseSet<ValuePair>::iterator T = PrunedTree.begin(), 1593 E2 = PrunedTree.end(); T != E2; ++T) { 1594 if (T->first == C->first.first || 1595 T->first == C->first.second || 1596 T->second == C->first.first || 1597 T->second == C->first.second || 1598 pairsConflict(*T, C->first, PairableInstUsers, 1599 UseCycleCheck ? &PairableInstUserMap : 0)) { 1600 CanAdd = false; 1601 break; 1602 } 1603 1604 CurrentPairs.insert(*T); 1605 } 1606 if (!CanAdd) continue; 1607 1608 // And check the queue too... 1609 for (SmallVector<ValuePairWithDepth, 32>::iterator C2 = Q.begin(), 1610 E2 = Q.end(); C2 != E2; ++C2) { 1611 if (C2->first.first == C->first.first || 1612 C2->first.first == C->first.second || 1613 C2->first.second == C->first.first || 1614 C2->first.second == C->first.second || 1615 pairsConflict(C2->first, C->first, PairableInstUsers, 1616 UseCycleCheck ? &PairableInstUserMap : 0)) { 1617 CanAdd = false; 1618 break; 1619 } 1620 1621 CurrentPairs.insert(C2->first); 1622 } 1623 if (!CanAdd) continue; 1624 1625 // Last but not least, check for a conflict with any of the 1626 // already-chosen pairs. 1627 for (DenseMap<Value *, Value *>::iterator C2 = 1628 ChosenPairs.begin(), E2 = ChosenPairs.end(); 1629 C2 != E2; ++C2) { 1630 if (pairsConflict(*C2, C->first, PairableInstUsers, 1631 UseCycleCheck ? &PairableInstUserMap : 0)) { 1632 CanAdd = false; 1633 break; 1634 } 1635 1636 CurrentPairs.insert(*C2); 1637 } 1638 if (!CanAdd) continue; 1639 1640 // To check for non-trivial cycles formed by the addition of the 1641 // current pair we've formed a list of all relevant pairs, now use a 1642 // graph walk to check for a cycle. We start from the current pair and 1643 // walk the use tree to see if we again reach the current pair. If we 1644 // do, then the current pair is rejected. 1645 1646 // FIXME: It may be more efficient to use a topological-ordering 1647 // algorithm to improve the cycle check. This should be investigated. 1648 if (UseCycleCheck && 1649 pairWillFormCycle(C->first, PairableInstUserMap, CurrentPairs)) 1650 continue; 1651 1652 // This child can be added, but we may have chosen it in preference 1653 // to an already-selected child. Check for this here, and if a 1654 // conflict is found, then remove the previously-selected child 1655 // before adding this one in its place. 1656 for (SmallVector<ValuePairWithDepth, 8>::iterator C2 1657 = BestChildren.begin(); C2 != BestChildren.end();) { 1658 if (C2->first.first == C->first.first || 1659 C2->first.first == C->first.second || 1660 C2->first.second == C->first.first || 1661 C2->first.second == C->first.second || 1662 pairsConflict(C2->first, C->first, PairableInstUsers)) 1663 C2 = BestChildren.erase(C2); 1664 else 1665 ++C2; 1666 } 1667 1668 BestChildren.push_back(ValuePairWithDepth(C->first, C->second)); 1669 } 1670 1671 for (SmallVector<ValuePairWithDepth, 8>::iterator C 1672 = BestChildren.begin(), E2 = BestChildren.end(); 1673 C != E2; ++C) { 1674 size_t DepthF = getDepthFactor(C->first.first); 1675 Q.push_back(ValuePairWithDepth(C->first, QTop.second+DepthF)); 1676 } 1677 } while (!Q.empty()); 1678 } 1679 1680 // This function finds the best tree of mututally-compatible connected 1681 // pairs, given the choice of root pairs as an iterator range. 1682 void BBVectorize::findBestTreeFor( 1683 std::multimap<Value *, Value *> &CandidatePairs, 1684 DenseMap<ValuePair, int> &CandidatePairCostSavings, 1685 std::vector<Value *> &PairableInsts, 1686 DenseSet<ValuePair> &FixedOrderPairs, 1687 DenseMap<VPPair, unsigned> &PairConnectionTypes, 1688 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 1689 std::multimap<ValuePair, ValuePair> &ConnectedPairDeps, 1690 DenseSet<ValuePair> &PairableInstUsers, 1691 std::multimap<ValuePair, ValuePair> &PairableInstUserMap, 1692 DenseMap<Value *, Value *> &ChosenPairs, 1693 DenseSet<ValuePair> &BestTree, size_t &BestMaxDepth, 1694 int &BestEffSize, VPIteratorPair ChoiceRange, 1695 bool UseCycleCheck) { 1696 for (std::multimap<Value *, Value *>::iterator J = ChoiceRange.first; 1697 J != ChoiceRange.second; ++J) { 1698 1699 // Before going any further, make sure that this pair does not 1700 // conflict with any already-selected pairs (see comment below 1701 // near the Tree pruning for more details). 1702 DenseSet<ValuePair> ChosenPairSet; 1703 bool DoesConflict = false; 1704 for (DenseMap<Value *, Value *>::iterator C = ChosenPairs.begin(), 1705 E = ChosenPairs.end(); C != E; ++C) { 1706 if (pairsConflict(*C, *J, PairableInstUsers, 1707 UseCycleCheck ? &PairableInstUserMap : 0)) { 1708 DoesConflict = true; 1709 break; 1710 } 1711 1712 ChosenPairSet.insert(*C); 1713 } 1714 if (DoesConflict) continue; 1715 1716 if (UseCycleCheck && 1717 pairWillFormCycle(*J, PairableInstUserMap, ChosenPairSet)) 1718 continue; 1719 1720 DenseMap<ValuePair, size_t> Tree; 1721 buildInitialTreeFor(CandidatePairs, PairableInsts, ConnectedPairs, 1722 PairableInstUsers, ChosenPairs, Tree, *J); 1723 1724 // Because we'll keep the child with the largest depth, the largest 1725 // depth is still the same in the unpruned Tree. 1726 size_t MaxDepth = Tree.lookup(*J); 1727 1728 DEBUG(if (DebugPairSelection) dbgs() << "BBV: found Tree for pair {" 1729 << *J->first << " <-> " << *J->second << "} of depth " << 1730 MaxDepth << " and size " << Tree.size() << "\n"); 1731 1732 // At this point the Tree has been constructed, but, may contain 1733 // contradictory children (meaning that different children of 1734 // some tree node may be attempting to fuse the same instruction). 1735 // So now we walk the tree again, in the case of a conflict, 1736 // keep only the child with the largest depth. To break a tie, 1737 // favor the first child. 1738 1739 DenseSet<ValuePair> PrunedTree; 1740 pruneTreeFor(CandidatePairs, PairableInsts, ConnectedPairs, 1741 PairableInstUsers, PairableInstUserMap, ChosenPairs, Tree, 1742 PrunedTree, *J, UseCycleCheck); 1743 1744 int EffSize = 0; 1745 if (TTI) { 1746 DenseSet<Value *> PrunedTreeInstrs; 1747 for (DenseSet<ValuePair>::iterator S = PrunedTree.begin(), 1748 E = PrunedTree.end(); S != E; ++S) { 1749 PrunedTreeInstrs.insert(S->first); 1750 PrunedTreeInstrs.insert(S->second); 1751 } 1752 1753 // The set of pairs that have already contributed to the total cost. 1754 DenseSet<ValuePair> IncomingPairs; 1755 1756 // If the cost model were perfect, this might not be necessary; but we 1757 // need to make sure that we don't get stuck vectorizing our own 1758 // shuffle chains. 1759 bool HasNontrivialInsts = false; 1760 1761 // The node weights represent the cost savings associated with 1762 // fusing the pair of instructions. 1763 for (DenseSet<ValuePair>::iterator S = PrunedTree.begin(), 1764 E = PrunedTree.end(); S != E; ++S) { 1765 if (!isa<ShuffleVectorInst>(S->first) && 1766 !isa<InsertElementInst>(S->first) && 1767 !isa<ExtractElementInst>(S->first)) 1768 HasNontrivialInsts = true; 1769 1770 bool FlipOrder = false; 1771 1772 if (getDepthFactor(S->first)) { 1773 int ESContrib = CandidatePairCostSavings.find(*S)->second; 1774 DEBUG(if (DebugPairSelection) dbgs() << "\tweight {" 1775 << *S->first << " <-> " << *S->second << "} = " << 1776 ESContrib << "\n"); 1777 EffSize += ESContrib; 1778 } 1779 1780 // The edge weights contribute in a negative sense: they represent 1781 // the cost of shuffles. 1782 VPPIteratorPair IP = ConnectedPairDeps.equal_range(*S); 1783 if (IP.first != ConnectedPairDeps.end()) { 1784 unsigned NumDepsDirect = 0, NumDepsSwap = 0; 1785 for (std::multimap<ValuePair, ValuePair>::iterator Q = IP.first; 1786 Q != IP.second; ++Q) { 1787 if (!PrunedTree.count(Q->second)) 1788 continue; 1789 DenseMap<VPPair, unsigned>::iterator R = 1790 PairConnectionTypes.find(VPPair(Q->second, Q->first)); 1791 assert(R != PairConnectionTypes.end() && 1792 "Cannot find pair connection type"); 1793 if (R->second == PairConnectionDirect) 1794 ++NumDepsDirect; 1795 else if (R->second == PairConnectionSwap) 1796 ++NumDepsSwap; 1797 } 1798 1799 // If there are more swaps than direct connections, then 1800 // the pair order will be flipped during fusion. So the real 1801 // number of swaps is the minimum number. 1802 FlipOrder = !FixedOrderPairs.count(*S) && 1803 ((NumDepsSwap > NumDepsDirect) || 1804 FixedOrderPairs.count(ValuePair(S->second, S->first))); 1805 1806 for (std::multimap<ValuePair, ValuePair>::iterator Q = IP.first; 1807 Q != IP.second; ++Q) { 1808 if (!PrunedTree.count(Q->second)) 1809 continue; 1810 DenseMap<VPPair, unsigned>::iterator R = 1811 PairConnectionTypes.find(VPPair(Q->second, Q->first)); 1812 assert(R != PairConnectionTypes.end() && 1813 "Cannot find pair connection type"); 1814 Type *Ty1 = Q->second.first->getType(), 1815 *Ty2 = Q->second.second->getType(); 1816 Type *VTy = getVecTypeForPair(Ty1, Ty2); 1817 if ((R->second == PairConnectionDirect && FlipOrder) || 1818 (R->second == PairConnectionSwap && !FlipOrder) || 1819 R->second == PairConnectionSplat) { 1820 int ESContrib = (int) getInstrCost(Instruction::ShuffleVector, 1821 VTy, VTy); 1822 DEBUG(if (DebugPairSelection) dbgs() << "\tcost {" << 1823 *Q->second.first << " <-> " << *Q->second.second << 1824 "} -> {" << 1825 *S->first << " <-> " << *S->second << "} = " << 1826 ESContrib << "\n"); 1827 EffSize -= ESContrib; 1828 } 1829 } 1830 } 1831 1832 // Compute the cost of outgoing edges. We assume that edges outgoing 1833 // to shuffles, inserts or extracts can be merged, and so contribute 1834 // no additional cost. 1835 if (!S->first->getType()->isVoidTy()) { 1836 Type *Ty1 = S->first->getType(), 1837 *Ty2 = S->second->getType(); 1838 Type *VTy = getVecTypeForPair(Ty1, Ty2); 1839 1840 bool NeedsExtraction = false; 1841 for (Value::use_iterator I = S->first->use_begin(), 1842 IE = S->first->use_end(); I != IE; ++I) { 1843 if (ShuffleVectorInst *SI = dyn_cast<ShuffleVectorInst>(*I)) { 1844 // Shuffle can be folded if it has no other input 1845 if (isa<UndefValue>(SI->getOperand(1))) 1846 continue; 1847 } 1848 if (isa<ExtractElementInst>(*I)) 1849 continue; 1850 if (PrunedTreeInstrs.count(*I)) 1851 continue; 1852 NeedsExtraction = true; 1853 break; 1854 } 1855 1856 if (NeedsExtraction) { 1857 int ESContrib; 1858 if (Ty1->isVectorTy()) 1859 ESContrib = (int) getInstrCost(Instruction::ShuffleVector, 1860 Ty1, VTy); 1861 else 1862 ESContrib = (int) TTI->getVectorInstrCost( 1863 Instruction::ExtractElement, VTy, 0); 1864 1865 DEBUG(if (DebugPairSelection) dbgs() << "\tcost {" << 1866 *S->first << "} = " << ESContrib << "\n"); 1867 EffSize -= ESContrib; 1868 } 1869 1870 NeedsExtraction = false; 1871 for (Value::use_iterator I = S->second->use_begin(), 1872 IE = S->second->use_end(); I != IE; ++I) { 1873 if (ShuffleVectorInst *SI = dyn_cast<ShuffleVectorInst>(*I)) { 1874 // Shuffle can be folded if it has no other input 1875 if (isa<UndefValue>(SI->getOperand(1))) 1876 continue; 1877 } 1878 if (isa<ExtractElementInst>(*I)) 1879 continue; 1880 if (PrunedTreeInstrs.count(*I)) 1881 continue; 1882 NeedsExtraction = true; 1883 break; 1884 } 1885 1886 if (NeedsExtraction) { 1887 int ESContrib; 1888 if (Ty2->isVectorTy()) 1889 ESContrib = (int) getInstrCost(Instruction::ShuffleVector, 1890 Ty2, VTy); 1891 else 1892 ESContrib = (int) TTI->getVectorInstrCost( 1893 Instruction::ExtractElement, VTy, 1); 1894 DEBUG(if (DebugPairSelection) dbgs() << "\tcost {" << 1895 *S->second << "} = " << ESContrib << "\n"); 1896 EffSize -= ESContrib; 1897 } 1898 } 1899 1900 // Compute the cost of incoming edges. 1901 if (!isa<LoadInst>(S->first) && !isa<StoreInst>(S->first)) { 1902 Instruction *S1 = cast<Instruction>(S->first), 1903 *S2 = cast<Instruction>(S->second); 1904 for (unsigned o = 0; o < S1->getNumOperands(); ++o) { 1905 Value *O1 = S1->getOperand(o), *O2 = S2->getOperand(o); 1906 1907 // Combining constants into vector constants (or small vector 1908 // constants into larger ones are assumed free). 1909 if (isa<Constant>(O1) && isa<Constant>(O2)) 1910 continue; 1911 1912 if (FlipOrder) 1913 std::swap(O1, O2); 1914 1915 ValuePair VP = ValuePair(O1, O2); 1916 ValuePair VPR = ValuePair(O2, O1); 1917 1918 // Internal edges are not handled here. 1919 if (PrunedTree.count(VP) || PrunedTree.count(VPR)) 1920 continue; 1921 1922 Type *Ty1 = O1->getType(), 1923 *Ty2 = O2->getType(); 1924 Type *VTy = getVecTypeForPair(Ty1, Ty2); 1925 1926 // Combining vector operations of the same type is also assumed 1927 // folded with other operations. 1928 if (Ty1 == Ty2) { 1929 // If both are insert elements, then both can be widened. 1930 InsertElementInst *IEO1 = dyn_cast<InsertElementInst>(O1), 1931 *IEO2 = dyn_cast<InsertElementInst>(O2); 1932 if (IEO1 && IEO2 && isPureIEChain(IEO1) && isPureIEChain(IEO2)) 1933 continue; 1934 // If both are extract elements, and both have the same input 1935 // type, then they can be replaced with a shuffle 1936 ExtractElementInst *EIO1 = dyn_cast<ExtractElementInst>(O1), 1937 *EIO2 = dyn_cast<ExtractElementInst>(O2); 1938 if (EIO1 && EIO2 && 1939 EIO1->getOperand(0)->getType() == 1940 EIO2->getOperand(0)->getType()) 1941 continue; 1942 // If both are a shuffle with equal operand types and only two 1943 // unqiue operands, then they can be replaced with a single 1944 // shuffle 1945 ShuffleVectorInst *SIO1 = dyn_cast<ShuffleVectorInst>(O1), 1946 *SIO2 = dyn_cast<ShuffleVectorInst>(O2); 1947 if (SIO1 && SIO2 && 1948 SIO1->getOperand(0)->getType() == 1949 SIO2->getOperand(0)->getType()) { 1950 SmallSet<Value *, 4> SIOps; 1951 SIOps.insert(SIO1->getOperand(0)); 1952 SIOps.insert(SIO1->getOperand(1)); 1953 SIOps.insert(SIO2->getOperand(0)); 1954 SIOps.insert(SIO2->getOperand(1)); 1955 if (SIOps.size() <= 2) 1956 continue; 1957 } 1958 } 1959 1960 int ESContrib; 1961 // This pair has already been formed. 1962 if (IncomingPairs.count(VP)) { 1963 continue; 1964 } else if (IncomingPairs.count(VPR)) { 1965 ESContrib = (int) getInstrCost(Instruction::ShuffleVector, 1966 VTy, VTy); 1967 } else if (!Ty1->isVectorTy() && !Ty2->isVectorTy()) { 1968 ESContrib = (int) TTI->getVectorInstrCost( 1969 Instruction::InsertElement, VTy, 0); 1970 ESContrib += (int) TTI->getVectorInstrCost( 1971 Instruction::InsertElement, VTy, 1); 1972 } else if (!Ty1->isVectorTy()) { 1973 // O1 needs to be inserted into a vector of size O2, and then 1974 // both need to be shuffled together. 1975 ESContrib = (int) TTI->getVectorInstrCost( 1976 Instruction::InsertElement, Ty2, 0); 1977 ESContrib += (int) getInstrCost(Instruction::ShuffleVector, 1978 VTy, Ty2); 1979 } else if (!Ty2->isVectorTy()) { 1980 // O2 needs to be inserted into a vector of size O1, and then 1981 // both need to be shuffled together. 1982 ESContrib = (int) TTI->getVectorInstrCost( 1983 Instruction::InsertElement, Ty1, 0); 1984 ESContrib += (int) getInstrCost(Instruction::ShuffleVector, 1985 VTy, Ty1); 1986 } else { 1987 Type *TyBig = Ty1, *TySmall = Ty2; 1988 if (Ty2->getVectorNumElements() > Ty1->getVectorNumElements()) 1989 std::swap(TyBig, TySmall); 1990 1991 ESContrib = (int) getInstrCost(Instruction::ShuffleVector, 1992 VTy, TyBig); 1993 if (TyBig != TySmall) 1994 ESContrib += (int) getInstrCost(Instruction::ShuffleVector, 1995 TyBig, TySmall); 1996 } 1997 1998 DEBUG(if (DebugPairSelection) dbgs() << "\tcost {" 1999 << *O1 << " <-> " << *O2 << "} = " << 2000 ESContrib << "\n"); 2001 EffSize -= ESContrib; 2002 IncomingPairs.insert(VP); 2003 } 2004 } 2005 } 2006 2007 if (!HasNontrivialInsts) { 2008 DEBUG(if (DebugPairSelection) dbgs() << 2009 "\tNo non-trivial instructions in tree;" 2010 " override to zero effective size\n"); 2011 EffSize = 0; 2012 } 2013 } else { 2014 for (DenseSet<ValuePair>::iterator S = PrunedTree.begin(), 2015 E = PrunedTree.end(); S != E; ++S) 2016 EffSize += (int) getDepthFactor(S->first); 2017 } 2018 2019 DEBUG(if (DebugPairSelection) 2020 dbgs() << "BBV: found pruned Tree for pair {" 2021 << *J->first << " <-> " << *J->second << "} of depth " << 2022 MaxDepth << " and size " << PrunedTree.size() << 2023 " (effective size: " << EffSize << ")\n"); 2024 if (((TTI && !UseChainDepthWithTI) || 2025 MaxDepth >= Config.ReqChainDepth) && 2026 EffSize > 0 && EffSize > BestEffSize) { 2027 BestMaxDepth = MaxDepth; 2028 BestEffSize = EffSize; 2029 BestTree = PrunedTree; 2030 } 2031 } 2032 } 2033 2034 // Given the list of candidate pairs, this function selects those 2035 // that will be fused into vector instructions. 2036 void BBVectorize::choosePairs( 2037 std::multimap<Value *, Value *> &CandidatePairs, 2038 DenseMap<ValuePair, int> &CandidatePairCostSavings, 2039 std::vector<Value *> &PairableInsts, 2040 DenseSet<ValuePair> &FixedOrderPairs, 2041 DenseMap<VPPair, unsigned> &PairConnectionTypes, 2042 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 2043 std::multimap<ValuePair, ValuePair> &ConnectedPairDeps, 2044 DenseSet<ValuePair> &PairableInstUsers, 2045 DenseMap<Value *, Value *>& ChosenPairs) { 2046 bool UseCycleCheck = 2047 CandidatePairs.size() <= Config.MaxCandPairsForCycleCheck; 2048 std::multimap<ValuePair, ValuePair> PairableInstUserMap; 2049 for (std::vector<Value *>::iterator I = PairableInsts.begin(), 2050 E = PairableInsts.end(); I != E; ++I) { 2051 // The number of possible pairings for this variable: 2052 size_t NumChoices = CandidatePairs.count(*I); 2053 if (!NumChoices) continue; 2054 2055 VPIteratorPair ChoiceRange = CandidatePairs.equal_range(*I); 2056 2057 // The best pair to choose and its tree: 2058 size_t BestMaxDepth = 0; 2059 int BestEffSize = 0; 2060 DenseSet<ValuePair> BestTree; 2061 findBestTreeFor(CandidatePairs, CandidatePairCostSavings, 2062 PairableInsts, FixedOrderPairs, PairConnectionTypes, 2063 ConnectedPairs, ConnectedPairDeps, 2064 PairableInstUsers, PairableInstUserMap, ChosenPairs, 2065 BestTree, BestMaxDepth, BestEffSize, ChoiceRange, 2066 UseCycleCheck); 2067 2068 // A tree has been chosen (or not) at this point. If no tree was 2069 // chosen, then this instruction, I, cannot be paired (and is no longer 2070 // considered). 2071 2072 DEBUG(if (BestTree.size() > 0) 2073 dbgs() << "BBV: selected pairs in the best tree for: " 2074 << *cast<Instruction>(*I) << "\n"); 2075 2076 for (DenseSet<ValuePair>::iterator S = BestTree.begin(), 2077 SE2 = BestTree.end(); S != SE2; ++S) { 2078 // Insert the members of this tree into the list of chosen pairs. 2079 ChosenPairs.insert(ValuePair(S->first, S->second)); 2080 DEBUG(dbgs() << "BBV: selected pair: " << *S->first << " <-> " << 2081 *S->second << "\n"); 2082 2083 // Remove all candidate pairs that have values in the chosen tree. 2084 for (std::multimap<Value *, Value *>::iterator K = 2085 CandidatePairs.begin(); K != CandidatePairs.end();) { 2086 if (K->first == S->first || K->second == S->first || 2087 K->second == S->second || K->first == S->second) { 2088 // Don't remove the actual pair chosen so that it can be used 2089 // in subsequent tree selections. 2090 if (!(K->first == S->first && K->second == S->second)) 2091 CandidatePairs.erase(K++); 2092 else 2093 ++K; 2094 } else { 2095 ++K; 2096 } 2097 } 2098 } 2099 } 2100 2101 DEBUG(dbgs() << "BBV: selected " << ChosenPairs.size() << " pairs.\n"); 2102 } 2103 2104 std::string getReplacementName(Instruction *I, bool IsInput, unsigned o, 2105 unsigned n = 0) { 2106 if (!I->hasName()) 2107 return ""; 2108 2109 return (I->getName() + (IsInput ? ".v.i" : ".v.r") + utostr(o) + 2110 (n > 0 ? "." + utostr(n) : "")).str(); 2111 } 2112 2113 // Returns the value that is to be used as the pointer input to the vector 2114 // instruction that fuses I with J. 2115 Value *BBVectorize::getReplacementPointerInput(LLVMContext& Context, 2116 Instruction *I, Instruction *J, unsigned o) { 2117 Value *IPtr, *JPtr; 2118 unsigned IAlignment, JAlignment, IAddressSpace, JAddressSpace; 2119 int64_t OffsetInElmts; 2120 2121 // Note: the analysis might fail here, that is why the pair order has 2122 // been precomputed (OffsetInElmts must be unused here). 2123 (void) getPairPtrInfo(I, J, IPtr, JPtr, IAlignment, JAlignment, 2124 IAddressSpace, JAddressSpace, 2125 OffsetInElmts, false); 2126 2127 // The pointer value is taken to be the one with the lowest offset. 2128 Value *VPtr = IPtr; 2129 2130 Type *ArgTypeI = cast<PointerType>(IPtr->getType())->getElementType(); 2131 Type *ArgTypeJ = cast<PointerType>(JPtr->getType())->getElementType(); 2132 Type *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ); 2133 Type *VArgPtrType = PointerType::get(VArgType, 2134 cast<PointerType>(IPtr->getType())->getAddressSpace()); 2135 return new BitCastInst(VPtr, VArgPtrType, getReplacementName(I, true, o), 2136 /* insert before */ I); 2137 } 2138 2139 void BBVectorize::fillNewShuffleMask(LLVMContext& Context, Instruction *J, 2140 unsigned MaskOffset, unsigned NumInElem, 2141 unsigned NumInElem1, unsigned IdxOffset, 2142 std::vector<Constant*> &Mask) { 2143 unsigned NumElem1 = cast<VectorType>(J->getType())->getNumElements(); 2144 for (unsigned v = 0; v < NumElem1; ++v) { 2145 int m = cast<ShuffleVectorInst>(J)->getMaskValue(v); 2146 if (m < 0) { 2147 Mask[v+MaskOffset] = UndefValue::get(Type::getInt32Ty(Context)); 2148 } else { 2149 unsigned mm = m + (int) IdxOffset; 2150 if (m >= (int) NumInElem1) 2151 mm += (int) NumInElem; 2152 2153 Mask[v+MaskOffset] = 2154 ConstantInt::get(Type::getInt32Ty(Context), mm); 2155 } 2156 } 2157 } 2158 2159 // Returns the value that is to be used as the vector-shuffle mask to the 2160 // vector instruction that fuses I with J. 2161 Value *BBVectorize::getReplacementShuffleMask(LLVMContext& Context, 2162 Instruction *I, Instruction *J) { 2163 // This is the shuffle mask. We need to append the second 2164 // mask to the first, and the numbers need to be adjusted. 2165 2166 Type *ArgTypeI = I->getType(); 2167 Type *ArgTypeJ = J->getType(); 2168 Type *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ); 2169 2170 unsigned NumElemI = cast<VectorType>(ArgTypeI)->getNumElements(); 2171 2172 // Get the total number of elements in the fused vector type. 2173 // By definition, this must equal the number of elements in 2174 // the final mask. 2175 unsigned NumElem = cast<VectorType>(VArgType)->getNumElements(); 2176 std::vector<Constant*> Mask(NumElem); 2177 2178 Type *OpTypeI = I->getOperand(0)->getType(); 2179 unsigned NumInElemI = cast<VectorType>(OpTypeI)->getNumElements(); 2180 Type *OpTypeJ = J->getOperand(0)->getType(); 2181 unsigned NumInElemJ = cast<VectorType>(OpTypeJ)->getNumElements(); 2182 2183 // The fused vector will be: 2184 // ----------------------------------------------------- 2185 // | NumInElemI | NumInElemJ | NumInElemI | NumInElemJ | 2186 // ----------------------------------------------------- 2187 // from which we'll extract NumElem total elements (where the first NumElemI 2188 // of them come from the mask in I and the remainder come from the mask 2189 // in J. 2190 2191 // For the mask from the first pair... 2192 fillNewShuffleMask(Context, I, 0, NumInElemJ, NumInElemI, 2193 0, Mask); 2194 2195 // For the mask from the second pair... 2196 fillNewShuffleMask(Context, J, NumElemI, NumInElemI, NumInElemJ, 2197 NumInElemI, Mask); 2198 2199 return ConstantVector::get(Mask); 2200 } 2201 2202 bool BBVectorize::expandIEChain(LLVMContext& Context, Instruction *I, 2203 Instruction *J, unsigned o, Value *&LOp, 2204 unsigned numElemL, 2205 Type *ArgTypeL, Type *ArgTypeH, 2206 bool IBeforeJ, unsigned IdxOff) { 2207 bool ExpandedIEChain = false; 2208 if (InsertElementInst *LIE = dyn_cast<InsertElementInst>(LOp)) { 2209 // If we have a pure insertelement chain, then this can be rewritten 2210 // into a chain that directly builds the larger type. 2211 if (isPureIEChain(LIE)) { 2212 SmallVector<Value *, 8> VectElemts(numElemL, 2213 UndefValue::get(ArgTypeL->getScalarType())); 2214 InsertElementInst *LIENext = LIE; 2215 do { 2216 unsigned Idx = 2217 cast<ConstantInt>(LIENext->getOperand(2))->getSExtValue(); 2218 VectElemts[Idx] = LIENext->getOperand(1); 2219 } while ((LIENext = 2220 dyn_cast<InsertElementInst>(LIENext->getOperand(0)))); 2221 2222 LIENext = 0; 2223 Value *LIEPrev = UndefValue::get(ArgTypeH); 2224 for (unsigned i = 0; i < numElemL; ++i) { 2225 if (isa<UndefValue>(VectElemts[i])) continue; 2226 LIENext = InsertElementInst::Create(LIEPrev, VectElemts[i], 2227 ConstantInt::get(Type::getInt32Ty(Context), 2228 i + IdxOff), 2229 getReplacementName(IBeforeJ ? I : J, 2230 true, o, i+1)); 2231 LIENext->insertBefore(IBeforeJ ? J : I); 2232 LIEPrev = LIENext; 2233 } 2234 2235 LOp = LIENext ? (Value*) LIENext : UndefValue::get(ArgTypeH); 2236 ExpandedIEChain = true; 2237 } 2238 } 2239 2240 return ExpandedIEChain; 2241 } 2242 2243 // Returns the value to be used as the specified operand of the vector 2244 // instruction that fuses I with J. 2245 Value *BBVectorize::getReplacementInput(LLVMContext& Context, Instruction *I, 2246 Instruction *J, unsigned o, bool IBeforeJ) { 2247 Value *CV0 = ConstantInt::get(Type::getInt32Ty(Context), 0); 2248 Value *CV1 = ConstantInt::get(Type::getInt32Ty(Context), 1); 2249 2250 // Compute the fused vector type for this operand 2251 Type *ArgTypeI = I->getOperand(o)->getType(); 2252 Type *ArgTypeJ = J->getOperand(o)->getType(); 2253 VectorType *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ); 2254 2255 Instruction *L = I, *H = J; 2256 Type *ArgTypeL = ArgTypeI, *ArgTypeH = ArgTypeJ; 2257 2258 unsigned numElemL; 2259 if (ArgTypeL->isVectorTy()) 2260 numElemL = cast<VectorType>(ArgTypeL)->getNumElements(); 2261 else 2262 numElemL = 1; 2263 2264 unsigned numElemH; 2265 if (ArgTypeH->isVectorTy()) 2266 numElemH = cast<VectorType>(ArgTypeH)->getNumElements(); 2267 else 2268 numElemH = 1; 2269 2270 Value *LOp = L->getOperand(o); 2271 Value *HOp = H->getOperand(o); 2272 unsigned numElem = VArgType->getNumElements(); 2273 2274 // First, we check if we can reuse the "original" vector outputs (if these 2275 // exist). We might need a shuffle. 2276 ExtractElementInst *LEE = dyn_cast<ExtractElementInst>(LOp); 2277 ExtractElementInst *HEE = dyn_cast<ExtractElementInst>(HOp); 2278 ShuffleVectorInst *LSV = dyn_cast<ShuffleVectorInst>(LOp); 2279 ShuffleVectorInst *HSV = dyn_cast<ShuffleVectorInst>(HOp); 2280 2281 // FIXME: If we're fusing shuffle instructions, then we can't apply this 2282 // optimization. The input vectors to the shuffle might be a different 2283 // length from the shuffle outputs. Unfortunately, the replacement 2284 // shuffle mask has already been formed, and the mask entries are sensitive 2285 // to the sizes of the inputs. 2286 bool IsSizeChangeShuffle = 2287 isa<ShuffleVectorInst>(L) && 2288 (LOp->getType() != L->getType() || HOp->getType() != H->getType()); 2289 2290 if ((LEE || LSV) && (HEE || HSV) && !IsSizeChangeShuffle) { 2291 // We can have at most two unique vector inputs. 2292 bool CanUseInputs = true; 2293 Value *I1, *I2 = 0; 2294 if (LEE) { 2295 I1 = LEE->getOperand(0); 2296 } else { 2297 I1 = LSV->getOperand(0); 2298 I2 = LSV->getOperand(1); 2299 if (I2 == I1 || isa<UndefValue>(I2)) 2300 I2 = 0; 2301 } 2302 2303 if (HEE) { 2304 Value *I3 = HEE->getOperand(0); 2305 if (!I2 && I3 != I1) 2306 I2 = I3; 2307 else if (I3 != I1 && I3 != I2) 2308 CanUseInputs = false; 2309 } else { 2310 Value *I3 = HSV->getOperand(0); 2311 if (!I2 && I3 != I1) 2312 I2 = I3; 2313 else if (I3 != I1 && I3 != I2) 2314 CanUseInputs = false; 2315 2316 if (CanUseInputs) { 2317 Value *I4 = HSV->getOperand(1); 2318 if (!isa<UndefValue>(I4)) { 2319 if (!I2 && I4 != I1) 2320 I2 = I4; 2321 else if (I4 != I1 && I4 != I2) 2322 CanUseInputs = false; 2323 } 2324 } 2325 } 2326 2327 if (CanUseInputs) { 2328 unsigned LOpElem = 2329 cast<VectorType>(cast<Instruction>(LOp)->getOperand(0)->getType()) 2330 ->getNumElements(); 2331 unsigned HOpElem = 2332 cast<VectorType>(cast<Instruction>(HOp)->getOperand(0)->getType()) 2333 ->getNumElements(); 2334 2335 // We have one or two input vectors. We need to map each index of the 2336 // operands to the index of the original vector. 2337 SmallVector<std::pair<int, int>, 8> II(numElem); 2338 for (unsigned i = 0; i < numElemL; ++i) { 2339 int Idx, INum; 2340 if (LEE) { 2341 Idx = 2342 cast<ConstantInt>(LEE->getOperand(1))->getSExtValue(); 2343 INum = LEE->getOperand(0) == I1 ? 0 : 1; 2344 } else { 2345 Idx = LSV->getMaskValue(i); 2346 if (Idx < (int) LOpElem) { 2347 INum = LSV->getOperand(0) == I1 ? 0 : 1; 2348 } else { 2349 Idx -= LOpElem; 2350 INum = LSV->getOperand(1) == I1 ? 0 : 1; 2351 } 2352 } 2353 2354 II[i] = std::pair<int, int>(Idx, INum); 2355 } 2356 for (unsigned i = 0; i < numElemH; ++i) { 2357 int Idx, INum; 2358 if (HEE) { 2359 Idx = 2360 cast<ConstantInt>(HEE->getOperand(1))->getSExtValue(); 2361 INum = HEE->getOperand(0) == I1 ? 0 : 1; 2362 } else { 2363 Idx = HSV->getMaskValue(i); 2364 if (Idx < (int) HOpElem) { 2365 INum = HSV->getOperand(0) == I1 ? 0 : 1; 2366 } else { 2367 Idx -= HOpElem; 2368 INum = HSV->getOperand(1) == I1 ? 0 : 1; 2369 } 2370 } 2371 2372 II[i + numElemL] = std::pair<int, int>(Idx, INum); 2373 } 2374 2375 // We now have an array which tells us from which index of which 2376 // input vector each element of the operand comes. 2377 VectorType *I1T = cast<VectorType>(I1->getType()); 2378 unsigned I1Elem = I1T->getNumElements(); 2379 2380 if (!I2) { 2381 // In this case there is only one underlying vector input. Check for 2382 // the trivial case where we can use the input directly. 2383 if (I1Elem == numElem) { 2384 bool ElemInOrder = true; 2385 for (unsigned i = 0; i < numElem; ++i) { 2386 if (II[i].first != (int) i && II[i].first != -1) { 2387 ElemInOrder = false; 2388 break; 2389 } 2390 } 2391 2392 if (ElemInOrder) 2393 return I1; 2394 } 2395 2396 // A shuffle is needed. 2397 std::vector<Constant *> Mask(numElem); 2398 for (unsigned i = 0; i < numElem; ++i) { 2399 int Idx = II[i].first; 2400 if (Idx == -1) 2401 Mask[i] = UndefValue::get(Type::getInt32Ty(Context)); 2402 else 2403 Mask[i] = ConstantInt::get(Type::getInt32Ty(Context), Idx); 2404 } 2405 2406 Instruction *S = 2407 new ShuffleVectorInst(I1, UndefValue::get(I1T), 2408 ConstantVector::get(Mask), 2409 getReplacementName(IBeforeJ ? I : J, 2410 true, o)); 2411 S->insertBefore(IBeforeJ ? J : I); 2412 return S; 2413 } 2414 2415 VectorType *I2T = cast<VectorType>(I2->getType()); 2416 unsigned I2Elem = I2T->getNumElements(); 2417 2418 // This input comes from two distinct vectors. The first step is to 2419 // make sure that both vectors are the same length. If not, the 2420 // smaller one will need to grow before they can be shuffled together. 2421 if (I1Elem < I2Elem) { 2422 std::vector<Constant *> Mask(I2Elem); 2423 unsigned v = 0; 2424 for (; v < I1Elem; ++v) 2425 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v); 2426 for (; v < I2Elem; ++v) 2427 Mask[v] = UndefValue::get(Type::getInt32Ty(Context)); 2428 2429 Instruction *NewI1 = 2430 new ShuffleVectorInst(I1, UndefValue::get(I1T), 2431 ConstantVector::get(Mask), 2432 getReplacementName(IBeforeJ ? I : J, 2433 true, o, 1)); 2434 NewI1->insertBefore(IBeforeJ ? J : I); 2435 I1 = NewI1; 2436 I1T = I2T; 2437 I1Elem = I2Elem; 2438 } else if (I1Elem > I2Elem) { 2439 std::vector<Constant *> Mask(I1Elem); 2440 unsigned v = 0; 2441 for (; v < I2Elem; ++v) 2442 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v); 2443 for (; v < I1Elem; ++v) 2444 Mask[v] = UndefValue::get(Type::getInt32Ty(Context)); 2445 2446 Instruction *NewI2 = 2447 new ShuffleVectorInst(I2, UndefValue::get(I2T), 2448 ConstantVector::get(Mask), 2449 getReplacementName(IBeforeJ ? I : J, 2450 true, o, 1)); 2451 NewI2->insertBefore(IBeforeJ ? J : I); 2452 I2 = NewI2; 2453 I2T = I1T; 2454 I2Elem = I1Elem; 2455 } 2456 2457 // Now that both I1 and I2 are the same length we can shuffle them 2458 // together (and use the result). 2459 std::vector<Constant *> Mask(numElem); 2460 for (unsigned v = 0; v < numElem; ++v) { 2461 if (II[v].first == -1) { 2462 Mask[v] = UndefValue::get(Type::getInt32Ty(Context)); 2463 } else { 2464 int Idx = II[v].first + II[v].second * I1Elem; 2465 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), Idx); 2466 } 2467 } 2468 2469 Instruction *NewOp = 2470 new ShuffleVectorInst(I1, I2, ConstantVector::get(Mask), 2471 getReplacementName(IBeforeJ ? I : J, true, o)); 2472 NewOp->insertBefore(IBeforeJ ? J : I); 2473 return NewOp; 2474 } 2475 } 2476 2477 Type *ArgType = ArgTypeL; 2478 if (numElemL < numElemH) { 2479 if (numElemL == 1 && expandIEChain(Context, I, J, o, HOp, numElemH, 2480 ArgTypeL, VArgType, IBeforeJ, 1)) { 2481 // This is another short-circuit case: we're combining a scalar into 2482 // a vector that is formed by an IE chain. We've just expanded the IE 2483 // chain, now insert the scalar and we're done. 2484 2485 Instruction *S = InsertElementInst::Create(HOp, LOp, CV0, 2486 getReplacementName(IBeforeJ ? I : J, true, o)); 2487 S->insertBefore(IBeforeJ ? J : I); 2488 return S; 2489 } else if (!expandIEChain(Context, I, J, o, LOp, numElemL, ArgTypeL, 2490 ArgTypeH, IBeforeJ)) { 2491 // The two vector inputs to the shuffle must be the same length, 2492 // so extend the smaller vector to be the same length as the larger one. 2493 Instruction *NLOp; 2494 if (numElemL > 1) { 2495 2496 std::vector<Constant *> Mask(numElemH); 2497 unsigned v = 0; 2498 for (; v < numElemL; ++v) 2499 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v); 2500 for (; v < numElemH; ++v) 2501 Mask[v] = UndefValue::get(Type::getInt32Ty(Context)); 2502 2503 NLOp = new ShuffleVectorInst(LOp, UndefValue::get(ArgTypeL), 2504 ConstantVector::get(Mask), 2505 getReplacementName(IBeforeJ ? I : J, 2506 true, o, 1)); 2507 } else { 2508 NLOp = InsertElementInst::Create(UndefValue::get(ArgTypeH), LOp, CV0, 2509 getReplacementName(IBeforeJ ? I : J, 2510 true, o, 1)); 2511 } 2512 2513 NLOp->insertBefore(IBeforeJ ? J : I); 2514 LOp = NLOp; 2515 } 2516 2517 ArgType = ArgTypeH; 2518 } else if (numElemL > numElemH) { 2519 if (numElemH == 1 && expandIEChain(Context, I, J, o, LOp, numElemL, 2520 ArgTypeH, VArgType, IBeforeJ)) { 2521 Instruction *S = 2522 InsertElementInst::Create(LOp, HOp, 2523 ConstantInt::get(Type::getInt32Ty(Context), 2524 numElemL), 2525 getReplacementName(IBeforeJ ? I : J, 2526 true, o)); 2527 S->insertBefore(IBeforeJ ? J : I); 2528 return S; 2529 } else if (!expandIEChain(Context, I, J, o, HOp, numElemH, ArgTypeH, 2530 ArgTypeL, IBeforeJ)) { 2531 Instruction *NHOp; 2532 if (numElemH > 1) { 2533 std::vector<Constant *> Mask(numElemL); 2534 unsigned v = 0; 2535 for (; v < numElemH; ++v) 2536 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v); 2537 for (; v < numElemL; ++v) 2538 Mask[v] = UndefValue::get(Type::getInt32Ty(Context)); 2539 2540 NHOp = new ShuffleVectorInst(HOp, UndefValue::get(ArgTypeH), 2541 ConstantVector::get(Mask), 2542 getReplacementName(IBeforeJ ? I : J, 2543 true, o, 1)); 2544 } else { 2545 NHOp = InsertElementInst::Create(UndefValue::get(ArgTypeL), HOp, CV0, 2546 getReplacementName(IBeforeJ ? I : J, 2547 true, o, 1)); 2548 } 2549 2550 NHOp->insertBefore(IBeforeJ ? J : I); 2551 HOp = NHOp; 2552 } 2553 } 2554 2555 if (ArgType->isVectorTy()) { 2556 unsigned numElem = cast<VectorType>(VArgType)->getNumElements(); 2557 std::vector<Constant*> Mask(numElem); 2558 for (unsigned v = 0; v < numElem; ++v) { 2559 unsigned Idx = v; 2560 // If the low vector was expanded, we need to skip the extra 2561 // undefined entries. 2562 if (v >= numElemL && numElemH > numElemL) 2563 Idx += (numElemH - numElemL); 2564 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), Idx); 2565 } 2566 2567 Instruction *BV = new ShuffleVectorInst(LOp, HOp, 2568 ConstantVector::get(Mask), 2569 getReplacementName(IBeforeJ ? I : J, true, o)); 2570 BV->insertBefore(IBeforeJ ? J : I); 2571 return BV; 2572 } 2573 2574 Instruction *BV1 = InsertElementInst::Create( 2575 UndefValue::get(VArgType), LOp, CV0, 2576 getReplacementName(IBeforeJ ? I : J, 2577 true, o, 1)); 2578 BV1->insertBefore(IBeforeJ ? J : I); 2579 Instruction *BV2 = InsertElementInst::Create(BV1, HOp, CV1, 2580 getReplacementName(IBeforeJ ? I : J, 2581 true, o, 2)); 2582 BV2->insertBefore(IBeforeJ ? J : I); 2583 return BV2; 2584 } 2585 2586 // This function creates an array of values that will be used as the inputs 2587 // to the vector instruction that fuses I with J. 2588 void BBVectorize::getReplacementInputsForPair(LLVMContext& Context, 2589 Instruction *I, Instruction *J, 2590 SmallVector<Value *, 3> &ReplacedOperands, 2591 bool IBeforeJ) { 2592 unsigned NumOperands = I->getNumOperands(); 2593 2594 for (unsigned p = 0, o = NumOperands-1; p < NumOperands; ++p, --o) { 2595 // Iterate backward so that we look at the store pointer 2596 // first and know whether or not we need to flip the inputs. 2597 2598 if (isa<LoadInst>(I) || (o == 1 && isa<StoreInst>(I))) { 2599 // This is the pointer for a load/store instruction. 2600 ReplacedOperands[o] = getReplacementPointerInput(Context, I, J, o); 2601 continue; 2602 } else if (isa<CallInst>(I)) { 2603 Function *F = cast<CallInst>(I)->getCalledFunction(); 2604 Intrinsic::ID IID = (Intrinsic::ID) F->getIntrinsicID(); 2605 if (o == NumOperands-1) { 2606 BasicBlock &BB = *I->getParent(); 2607 2608 Module *M = BB.getParent()->getParent(); 2609 Type *ArgTypeI = I->getType(); 2610 Type *ArgTypeJ = J->getType(); 2611 Type *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ); 2612 2613 ReplacedOperands[o] = Intrinsic::getDeclaration(M, IID, VArgType); 2614 continue; 2615 } else if (IID == Intrinsic::powi && o == 1) { 2616 // The second argument of powi is a single integer and we've already 2617 // checked that both arguments are equal. As a result, we just keep 2618 // I's second argument. 2619 ReplacedOperands[o] = I->getOperand(o); 2620 continue; 2621 } 2622 } else if (isa<ShuffleVectorInst>(I) && o == NumOperands-1) { 2623 ReplacedOperands[o] = getReplacementShuffleMask(Context, I, J); 2624 continue; 2625 } 2626 2627 ReplacedOperands[o] = getReplacementInput(Context, I, J, o, IBeforeJ); 2628 } 2629 } 2630 2631 // This function creates two values that represent the outputs of the 2632 // original I and J instructions. These are generally vector shuffles 2633 // or extracts. In many cases, these will end up being unused and, thus, 2634 // eliminated by later passes. 2635 void BBVectorize::replaceOutputsOfPair(LLVMContext& Context, Instruction *I, 2636 Instruction *J, Instruction *K, 2637 Instruction *&InsertionPt, 2638 Instruction *&K1, Instruction *&K2) { 2639 if (isa<StoreInst>(I)) { 2640 AA->replaceWithNewValue(I, K); 2641 AA->replaceWithNewValue(J, K); 2642 } else { 2643 Type *IType = I->getType(); 2644 Type *JType = J->getType(); 2645 2646 VectorType *VType = getVecTypeForPair(IType, JType); 2647 unsigned numElem = VType->getNumElements(); 2648 2649 unsigned numElemI, numElemJ; 2650 if (IType->isVectorTy()) 2651 numElemI = cast<VectorType>(IType)->getNumElements(); 2652 else 2653 numElemI = 1; 2654 2655 if (JType->isVectorTy()) 2656 numElemJ = cast<VectorType>(JType)->getNumElements(); 2657 else 2658 numElemJ = 1; 2659 2660 if (IType->isVectorTy()) { 2661 std::vector<Constant*> Mask1(numElemI), Mask2(numElemI); 2662 for (unsigned v = 0; v < numElemI; ++v) { 2663 Mask1[v] = ConstantInt::get(Type::getInt32Ty(Context), v); 2664 Mask2[v] = ConstantInt::get(Type::getInt32Ty(Context), numElemJ+v); 2665 } 2666 2667 K1 = new ShuffleVectorInst(K, UndefValue::get(VType), 2668 ConstantVector::get( Mask1), 2669 getReplacementName(K, false, 1)); 2670 } else { 2671 Value *CV0 = ConstantInt::get(Type::getInt32Ty(Context), 0); 2672 K1 = ExtractElementInst::Create(K, CV0, 2673 getReplacementName(K, false, 1)); 2674 } 2675 2676 if (JType->isVectorTy()) { 2677 std::vector<Constant*> Mask1(numElemJ), Mask2(numElemJ); 2678 for (unsigned v = 0; v < numElemJ; ++v) { 2679 Mask1[v] = ConstantInt::get(Type::getInt32Ty(Context), v); 2680 Mask2[v] = ConstantInt::get(Type::getInt32Ty(Context), numElemI+v); 2681 } 2682 2683 K2 = new ShuffleVectorInst(K, UndefValue::get(VType), 2684 ConstantVector::get( Mask2), 2685 getReplacementName(K, false, 2)); 2686 } else { 2687 Value *CV1 = ConstantInt::get(Type::getInt32Ty(Context), numElem-1); 2688 K2 = ExtractElementInst::Create(K, CV1, 2689 getReplacementName(K, false, 2)); 2690 } 2691 2692 K1->insertAfter(K); 2693 K2->insertAfter(K1); 2694 InsertionPt = K2; 2695 } 2696 } 2697 2698 // Move all uses of the function I (including pairing-induced uses) after J. 2699 bool BBVectorize::canMoveUsesOfIAfterJ(BasicBlock &BB, 2700 std::multimap<Value *, Value *> &LoadMoveSet, 2701 Instruction *I, Instruction *J) { 2702 // Skip to the first instruction past I. 2703 BasicBlock::iterator L = llvm::next(BasicBlock::iterator(I)); 2704 2705 DenseSet<Value *> Users; 2706 AliasSetTracker WriteSet(*AA); 2707 for (; cast<Instruction>(L) != J; ++L) 2708 (void) trackUsesOfI(Users, WriteSet, I, L, true, &LoadMoveSet); 2709 2710 assert(cast<Instruction>(L) == J && 2711 "Tracking has not proceeded far enough to check for dependencies"); 2712 // If J is now in the use set of I, then trackUsesOfI will return true 2713 // and we have a dependency cycle (and the fusing operation must abort). 2714 return !trackUsesOfI(Users, WriteSet, I, J, true, &LoadMoveSet); 2715 } 2716 2717 // Move all uses of the function I (including pairing-induced uses) after J. 2718 void BBVectorize::moveUsesOfIAfterJ(BasicBlock &BB, 2719 std::multimap<Value *, Value *> &LoadMoveSet, 2720 Instruction *&InsertionPt, 2721 Instruction *I, Instruction *J) { 2722 // Skip to the first instruction past I. 2723 BasicBlock::iterator L = llvm::next(BasicBlock::iterator(I)); 2724 2725 DenseSet<Value *> Users; 2726 AliasSetTracker WriteSet(*AA); 2727 for (; cast<Instruction>(L) != J;) { 2728 if (trackUsesOfI(Users, WriteSet, I, L, true, &LoadMoveSet)) { 2729 // Move this instruction 2730 Instruction *InstToMove = L; ++L; 2731 2732 DEBUG(dbgs() << "BBV: moving: " << *InstToMove << 2733 " to after " << *InsertionPt << "\n"); 2734 InstToMove->removeFromParent(); 2735 InstToMove->insertAfter(InsertionPt); 2736 InsertionPt = InstToMove; 2737 } else { 2738 ++L; 2739 } 2740 } 2741 } 2742 2743 // Collect all load instruction that are in the move set of a given first 2744 // pair member. These loads depend on the first instruction, I, and so need 2745 // to be moved after J (the second instruction) when the pair is fused. 2746 void BBVectorize::collectPairLoadMoveSet(BasicBlock &BB, 2747 DenseMap<Value *, Value *> &ChosenPairs, 2748 std::multimap<Value *, Value *> &LoadMoveSet, 2749 Instruction *I) { 2750 // Skip to the first instruction past I. 2751 BasicBlock::iterator L = llvm::next(BasicBlock::iterator(I)); 2752 2753 DenseSet<Value *> Users; 2754 AliasSetTracker WriteSet(*AA); 2755 2756 // Note: We cannot end the loop when we reach J because J could be moved 2757 // farther down the use chain by another instruction pairing. Also, J 2758 // could be before I if this is an inverted input. 2759 for (BasicBlock::iterator E = BB.end(); cast<Instruction>(L) != E; ++L) { 2760 if (trackUsesOfI(Users, WriteSet, I, L)) { 2761 if (L->mayReadFromMemory()) 2762 LoadMoveSet.insert(ValuePair(L, I)); 2763 } 2764 } 2765 } 2766 2767 // In cases where both load/stores and the computation of their pointers 2768 // are chosen for vectorization, we can end up in a situation where the 2769 // aliasing analysis starts returning different query results as the 2770 // process of fusing instruction pairs continues. Because the algorithm 2771 // relies on finding the same use trees here as were found earlier, we'll 2772 // need to precompute the necessary aliasing information here and then 2773 // manually update it during the fusion process. 2774 void BBVectorize::collectLoadMoveSet(BasicBlock &BB, 2775 std::vector<Value *> &PairableInsts, 2776 DenseMap<Value *, Value *> &ChosenPairs, 2777 std::multimap<Value *, Value *> &LoadMoveSet) { 2778 for (std::vector<Value *>::iterator PI = PairableInsts.begin(), 2779 PIE = PairableInsts.end(); PI != PIE; ++PI) { 2780 DenseMap<Value *, Value *>::iterator P = ChosenPairs.find(*PI); 2781 if (P == ChosenPairs.end()) continue; 2782 2783 Instruction *I = cast<Instruction>(P->first); 2784 collectPairLoadMoveSet(BB, ChosenPairs, LoadMoveSet, I); 2785 } 2786 } 2787 2788 // When the first instruction in each pair is cloned, it will inherit its 2789 // parent's metadata. This metadata must be combined with that of the other 2790 // instruction in a safe way. 2791 void BBVectorize::combineMetadata(Instruction *K, const Instruction *J) { 2792 SmallVector<std::pair<unsigned, MDNode*>, 4> Metadata; 2793 K->getAllMetadataOtherThanDebugLoc(Metadata); 2794 for (unsigned i = 0, n = Metadata.size(); i < n; ++i) { 2795 unsigned Kind = Metadata[i].first; 2796 MDNode *JMD = J->getMetadata(Kind); 2797 MDNode *KMD = Metadata[i].second; 2798 2799 switch (Kind) { 2800 default: 2801 K->setMetadata(Kind, 0); // Remove unknown metadata 2802 break; 2803 case LLVMContext::MD_tbaa: 2804 K->setMetadata(Kind, MDNode::getMostGenericTBAA(JMD, KMD)); 2805 break; 2806 case LLVMContext::MD_fpmath: 2807 K->setMetadata(Kind, MDNode::getMostGenericFPMath(JMD, KMD)); 2808 break; 2809 } 2810 } 2811 } 2812 2813 // This function fuses the chosen instruction pairs into vector instructions, 2814 // taking care preserve any needed scalar outputs and, then, it reorders the 2815 // remaining instructions as needed (users of the first member of the pair 2816 // need to be moved to after the location of the second member of the pair 2817 // because the vector instruction is inserted in the location of the pair's 2818 // second member). 2819 void BBVectorize::fuseChosenPairs(BasicBlock &BB, 2820 std::vector<Value *> &PairableInsts, 2821 DenseMap<Value *, Value *> &ChosenPairs, 2822 DenseSet<ValuePair> &FixedOrderPairs, 2823 DenseMap<VPPair, unsigned> &PairConnectionTypes, 2824 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 2825 std::multimap<ValuePair, ValuePair> &ConnectedPairDeps) { 2826 LLVMContext& Context = BB.getContext(); 2827 2828 // During the vectorization process, the order of the pairs to be fused 2829 // could be flipped. So we'll add each pair, flipped, into the ChosenPairs 2830 // list. After a pair is fused, the flipped pair is removed from the list. 2831 DenseSet<ValuePair> FlippedPairs; 2832 for (DenseMap<Value *, Value *>::iterator P = ChosenPairs.begin(), 2833 E = ChosenPairs.end(); P != E; ++P) 2834 FlippedPairs.insert(ValuePair(P->second, P->first)); 2835 for (DenseSet<ValuePair>::iterator P = FlippedPairs.begin(), 2836 E = FlippedPairs.end(); P != E; ++P) 2837 ChosenPairs.insert(*P); 2838 2839 std::multimap<Value *, Value *> LoadMoveSet; 2840 collectLoadMoveSet(BB, PairableInsts, ChosenPairs, LoadMoveSet); 2841 2842 DEBUG(dbgs() << "BBV: initial: \n" << BB << "\n"); 2843 2844 for (BasicBlock::iterator PI = BB.getFirstInsertionPt(); PI != BB.end();) { 2845 DenseMap<Value *, Value *>::iterator P = ChosenPairs.find(PI); 2846 if (P == ChosenPairs.end()) { 2847 ++PI; 2848 continue; 2849 } 2850 2851 if (getDepthFactor(P->first) == 0) { 2852 // These instructions are not really fused, but are tracked as though 2853 // they are. Any case in which it would be interesting to fuse them 2854 // will be taken care of by InstCombine. 2855 --NumFusedOps; 2856 ++PI; 2857 continue; 2858 } 2859 2860 Instruction *I = cast<Instruction>(P->first), 2861 *J = cast<Instruction>(P->second); 2862 2863 DEBUG(dbgs() << "BBV: fusing: " << *I << 2864 " <-> " << *J << "\n"); 2865 2866 // Remove the pair and flipped pair from the list. 2867 DenseMap<Value *, Value *>::iterator FP = ChosenPairs.find(P->second); 2868 assert(FP != ChosenPairs.end() && "Flipped pair not found in list"); 2869 ChosenPairs.erase(FP); 2870 ChosenPairs.erase(P); 2871 2872 if (!canMoveUsesOfIAfterJ(BB, LoadMoveSet, I, J)) { 2873 DEBUG(dbgs() << "BBV: fusion of: " << *I << 2874 " <-> " << *J << 2875 " aborted because of non-trivial dependency cycle\n"); 2876 --NumFusedOps; 2877 ++PI; 2878 continue; 2879 } 2880 2881 // If the pair must have the other order, then flip it. 2882 bool FlipPairOrder = FixedOrderPairs.count(ValuePair(J, I)); 2883 if (!FlipPairOrder && !FixedOrderPairs.count(ValuePair(I, J))) { 2884 // This pair does not have a fixed order, and so we might want to 2885 // flip it if that will yield fewer shuffles. We count the number 2886 // of dependencies connected via swaps, and those directly connected, 2887 // and flip the order if the number of swaps is greater. 2888 bool OrigOrder = true; 2889 VPPIteratorPair IP = ConnectedPairDeps.equal_range(ValuePair(I, J)); 2890 if (IP.first == ConnectedPairDeps.end()) { 2891 IP = ConnectedPairDeps.equal_range(ValuePair(J, I)); 2892 OrigOrder = false; 2893 } 2894 2895 if (IP.first != ConnectedPairDeps.end()) { 2896 unsigned NumDepsDirect = 0, NumDepsSwap = 0; 2897 for (std::multimap<ValuePair, ValuePair>::iterator Q = IP.first; 2898 Q != IP.second; ++Q) { 2899 DenseMap<VPPair, unsigned>::iterator R = 2900 PairConnectionTypes.find(VPPair(Q->second, Q->first)); 2901 assert(R != PairConnectionTypes.end() && 2902 "Cannot find pair connection type"); 2903 if (R->second == PairConnectionDirect) 2904 ++NumDepsDirect; 2905 else if (R->second == PairConnectionSwap) 2906 ++NumDepsSwap; 2907 } 2908 2909 if (!OrigOrder) 2910 std::swap(NumDepsDirect, NumDepsSwap); 2911 2912 if (NumDepsSwap > NumDepsDirect) { 2913 FlipPairOrder = true; 2914 DEBUG(dbgs() << "BBV: reordering pair: " << *I << 2915 " <-> " << *J << "\n"); 2916 } 2917 } 2918 } 2919 2920 Instruction *L = I, *H = J; 2921 if (FlipPairOrder) 2922 std::swap(H, L); 2923 2924 // If the pair being fused uses the opposite order from that in the pair 2925 // connection map, then we need to flip the types. 2926 VPPIteratorPair IP = ConnectedPairs.equal_range(ValuePair(H, L)); 2927 for (std::multimap<ValuePair, ValuePair>::iterator Q = IP.first; 2928 Q != IP.second; ++Q) { 2929 DenseMap<VPPair, unsigned>::iterator R = PairConnectionTypes.find(*Q); 2930 assert(R != PairConnectionTypes.end() && 2931 "Cannot find pair connection type"); 2932 if (R->second == PairConnectionDirect) 2933 R->second = PairConnectionSwap; 2934 else if (R->second == PairConnectionSwap) 2935 R->second = PairConnectionDirect; 2936 } 2937 2938 bool LBeforeH = !FlipPairOrder; 2939 unsigned NumOperands = I->getNumOperands(); 2940 SmallVector<Value *, 3> ReplacedOperands(NumOperands); 2941 getReplacementInputsForPair(Context, L, H, ReplacedOperands, 2942 LBeforeH); 2943 2944 // Make a copy of the original operation, change its type to the vector 2945 // type and replace its operands with the vector operands. 2946 Instruction *K = L->clone(); 2947 if (L->hasName()) 2948 K->takeName(L); 2949 else if (H->hasName()) 2950 K->takeName(H); 2951 2952 if (!isa<StoreInst>(K)) 2953 K->mutateType(getVecTypeForPair(L->getType(), H->getType())); 2954 2955 combineMetadata(K, H); 2956 K->intersectOptionalDataWith(H); 2957 2958 for (unsigned o = 0; o < NumOperands; ++o) 2959 K->setOperand(o, ReplacedOperands[o]); 2960 2961 K->insertAfter(J); 2962 2963 // Instruction insertion point: 2964 Instruction *InsertionPt = K; 2965 Instruction *K1 = 0, *K2 = 0; 2966 replaceOutputsOfPair(Context, L, H, K, InsertionPt, K1, K2); 2967 2968 // The use tree of the first original instruction must be moved to after 2969 // the location of the second instruction. The entire use tree of the 2970 // first instruction is disjoint from the input tree of the second 2971 // (by definition), and so commutes with it. 2972 2973 moveUsesOfIAfterJ(BB, LoadMoveSet, InsertionPt, I, J); 2974 2975 if (!isa<StoreInst>(I)) { 2976 L->replaceAllUsesWith(K1); 2977 H->replaceAllUsesWith(K2); 2978 AA->replaceWithNewValue(L, K1); 2979 AA->replaceWithNewValue(H, K2); 2980 } 2981 2982 // Instructions that may read from memory may be in the load move set. 2983 // Once an instruction is fused, we no longer need its move set, and so 2984 // the values of the map never need to be updated. However, when a load 2985 // is fused, we need to merge the entries from both instructions in the 2986 // pair in case those instructions were in the move set of some other 2987 // yet-to-be-fused pair. The loads in question are the keys of the map. 2988 if (I->mayReadFromMemory()) { 2989 std::vector<ValuePair> NewSetMembers; 2990 VPIteratorPair IPairRange = LoadMoveSet.equal_range(I); 2991 VPIteratorPair JPairRange = LoadMoveSet.equal_range(J); 2992 for (std::multimap<Value *, Value *>::iterator N = IPairRange.first; 2993 N != IPairRange.second; ++N) 2994 NewSetMembers.push_back(ValuePair(K, N->second)); 2995 for (std::multimap<Value *, Value *>::iterator N = JPairRange.first; 2996 N != JPairRange.second; ++N) 2997 NewSetMembers.push_back(ValuePair(K, N->second)); 2998 for (std::vector<ValuePair>::iterator A = NewSetMembers.begin(), 2999 AE = NewSetMembers.end(); A != AE; ++A) 3000 LoadMoveSet.insert(*A); 3001 } 3002 3003 // Before removing I, set the iterator to the next instruction. 3004 PI = llvm::next(BasicBlock::iterator(I)); 3005 if (cast<Instruction>(PI) == J) 3006 ++PI; 3007 3008 SE->forgetValue(I); 3009 SE->forgetValue(J); 3010 I->eraseFromParent(); 3011 J->eraseFromParent(); 3012 3013 DEBUG(if (PrintAfterEveryPair) dbgs() << "BBV: block is now: \n" << 3014 BB << "\n"); 3015 } 3016 3017 DEBUG(dbgs() << "BBV: final: \n" << BB << "\n"); 3018 } 3019} 3020 3021char BBVectorize::ID = 0; 3022static const char bb_vectorize_name[] = "Basic-Block Vectorization"; 3023INITIALIZE_PASS_BEGIN(BBVectorize, BBV_NAME, bb_vectorize_name, false, false) 3024INITIALIZE_AG_DEPENDENCY(AliasAnalysis) 3025INITIALIZE_PASS_DEPENDENCY(DominatorTree) 3026INITIALIZE_PASS_DEPENDENCY(ScalarEvolution) 3027INITIALIZE_PASS_END(BBVectorize, BBV_NAME, bb_vectorize_name, false, false) 3028 3029BasicBlockPass *llvm::createBBVectorizePass(const VectorizeConfig &C) { 3030 return new BBVectorize(C); 3031} 3032 3033bool 3034llvm::vectorizeBasicBlock(Pass *P, BasicBlock &BB, const VectorizeConfig &C) { 3035 BBVectorize BBVectorizer(P, C); 3036 return BBVectorizer.vectorizeBB(BB); 3037} 3038 3039//===----------------------------------------------------------------------===// 3040VectorizeConfig::VectorizeConfig() { 3041 VectorBits = ::VectorBits; 3042 VectorizeBools = !::NoBools; 3043 VectorizeInts = !::NoInts; 3044 VectorizeFloats = !::NoFloats; 3045 VectorizePointers = !::NoPointers; 3046 VectorizeCasts = !::NoCasts; 3047 VectorizeMath = !::NoMath; 3048 VectorizeFMA = !::NoFMA; 3049 VectorizeSelect = !::NoSelect; 3050 VectorizeCmp = !::NoCmp; 3051 VectorizeGEP = !::NoGEP; 3052 VectorizeMemOps = !::NoMemOps; 3053 AlignedOnly = ::AlignedOnly; 3054 ReqChainDepth= ::ReqChainDepth; 3055 SearchLimit = ::SearchLimit; 3056 MaxCandPairsForCycleCheck = ::MaxCandPairsForCycleCheck; 3057 SplatBreaksChain = ::SplatBreaksChain; 3058 MaxInsts = ::MaxInsts; 3059 MaxIter = ::MaxIter; 3060 Pow2LenOnly = ::Pow2LenOnly; 3061 NoMemOpBoost = ::NoMemOpBoost; 3062 FastDep = ::FastDep; 3063} 3064