BBVectorize.cpp revision 97d19ebe5b5bf27617e536a16fa232116cefe914
1//===- BBVectorize.cpp - A Basic-Block Vectorizer -------------------------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file implements a basic-block vectorization pass. The algorithm was 11// inspired by that used by the Vienna MAP Vectorizor by Franchetti and Kral, 12// et al. It works by looking for chains of pairable operations and then 13// pairing them. 14// 15//===----------------------------------------------------------------------===// 16 17#define BBV_NAME "bb-vectorize" 18#define DEBUG_TYPE BBV_NAME 19#include "llvm/Constants.h" 20#include "llvm/DerivedTypes.h" 21#include "llvm/Function.h" 22#include "llvm/Instructions.h" 23#include "llvm/IntrinsicInst.h" 24#include "llvm/Intrinsics.h" 25#include "llvm/LLVMContext.h" 26#include "llvm/Metadata.h" 27#include "llvm/Pass.h" 28#include "llvm/Type.h" 29#include "llvm/ADT/DenseMap.h" 30#include "llvm/ADT/DenseSet.h" 31#include "llvm/ADT/SmallSet.h" 32#include "llvm/ADT/SmallVector.h" 33#include "llvm/ADT/Statistic.h" 34#include "llvm/ADT/STLExtras.h" 35#include "llvm/ADT/StringExtras.h" 36#include "llvm/Analysis/AliasAnalysis.h" 37#include "llvm/Analysis/AliasSetTracker.h" 38#include "llvm/Analysis/Dominators.h" 39#include "llvm/Analysis/ScalarEvolution.h" 40#include "llvm/Analysis/ScalarEvolutionExpressions.h" 41#include "llvm/Analysis/ValueTracking.h" 42#include "llvm/Support/CommandLine.h" 43#include "llvm/Support/Debug.h" 44#include "llvm/Support/raw_ostream.h" 45#include "llvm/Support/ValueHandle.h" 46#include "llvm/DataLayout.h" 47#include "llvm/TargetTransformInfo.h" 48#include "llvm/Transforms/Utils/Local.h" 49#include "llvm/Transforms/Vectorize.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 VTTI = TTI ? TTI->getVectorTargetTransformInfo() : 0; 205 } 206 207 typedef std::pair<Value *, Value *> ValuePair; 208 typedef std::pair<ValuePair, int> ValuePairWithCost; 209 typedef std::pair<ValuePair, size_t> ValuePairWithDepth; 210 typedef std::pair<ValuePair, ValuePair> VPPair; // A ValuePair pair 211 typedef std::pair<VPPair, unsigned> VPPairWithType; 212 typedef std::pair<std::multimap<Value *, Value *>::iterator, 213 std::multimap<Value *, Value *>::iterator> VPIteratorPair; 214 typedef std::pair<std::multimap<ValuePair, ValuePair>::iterator, 215 std::multimap<ValuePair, ValuePair>::iterator> 216 VPPIteratorPair; 217 218 AliasAnalysis *AA; 219 DominatorTree *DT; 220 ScalarEvolution *SE; 221 DataLayout *TD; 222 TargetTransformInfo *TTI; 223 const VectorTargetTransformInfo *VTTI; 224 225 // FIXME: const correct? 226 227 bool vectorizePairs(BasicBlock &BB, bool NonPow2Len = false); 228 229 bool getCandidatePairs(BasicBlock &BB, 230 BasicBlock::iterator &Start, 231 std::multimap<Value *, Value *> &CandidatePairs, 232 DenseSet<ValuePair> &FixedOrderPairs, 233 DenseMap<ValuePair, int> &CandidatePairCostSavings, 234 std::vector<Value *> &PairableInsts, bool NonPow2Len); 235 236 // FIXME: The current implementation does not account for pairs that 237 // are connected in multiple ways. For example: 238 // C1 = A1 / A2; C2 = A2 / A1 (which may be both direct and a swap) 239 enum PairConnectionType { 240 PairConnectionDirect, 241 PairConnectionSwap, 242 PairConnectionSplat 243 }; 244 245 void computeConnectedPairs(std::multimap<Value *, Value *> &CandidatePairs, 246 std::vector<Value *> &PairableInsts, 247 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 248 DenseMap<VPPair, unsigned> &PairConnectionTypes); 249 250 void buildDepMap(BasicBlock &BB, 251 std::multimap<Value *, Value *> &CandidatePairs, 252 std::vector<Value *> &PairableInsts, 253 DenseSet<ValuePair> &PairableInstUsers); 254 255 void choosePairs(std::multimap<Value *, Value *> &CandidatePairs, 256 DenseMap<ValuePair, int> &CandidatePairCostSavings, 257 std::vector<Value *> &PairableInsts, 258 DenseSet<ValuePair> &FixedOrderPairs, 259 DenseMap<VPPair, unsigned> &PairConnectionTypes, 260 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 261 std::multimap<ValuePair, ValuePair> &ConnectedPairDeps, 262 DenseSet<ValuePair> &PairableInstUsers, 263 DenseMap<Value *, Value *>& ChosenPairs); 264 265 void fuseChosenPairs(BasicBlock &BB, 266 std::vector<Value *> &PairableInsts, 267 DenseMap<Value *, Value *>& ChosenPairs, 268 DenseSet<ValuePair> &FixedOrderPairs, 269 DenseMap<VPPair, unsigned> &PairConnectionTypes, 270 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 271 std::multimap<ValuePair, ValuePair> &ConnectedPairDeps); 272 273 274 bool isInstVectorizable(Instruction *I, bool &IsSimpleLoadStore); 275 276 bool areInstsCompatible(Instruction *I, Instruction *J, 277 bool IsSimpleLoadStore, bool NonPow2Len, 278 int &CostSavings, int &FixedOrder); 279 280 bool trackUsesOfI(DenseSet<Value *> &Users, 281 AliasSetTracker &WriteSet, Instruction *I, 282 Instruction *J, bool UpdateUsers = true, 283 std::multimap<Value *, Value *> *LoadMoveSet = 0); 284 285 void computePairsConnectedTo( 286 std::multimap<Value *, Value *> &CandidatePairs, 287 std::vector<Value *> &PairableInsts, 288 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 289 DenseMap<VPPair, unsigned> &PairConnectionTypes, 290 ValuePair P); 291 292 bool pairsConflict(ValuePair P, ValuePair Q, 293 DenseSet<ValuePair> &PairableInstUsers, 294 std::multimap<ValuePair, ValuePair> *PairableInstUserMap = 0); 295 296 bool pairWillFormCycle(ValuePair P, 297 std::multimap<ValuePair, ValuePair> &PairableInstUsers, 298 DenseSet<ValuePair> &CurrentPairs); 299 300 void pruneTreeFor( 301 std::multimap<Value *, Value *> &CandidatePairs, 302 std::vector<Value *> &PairableInsts, 303 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 304 DenseSet<ValuePair> &PairableInstUsers, 305 std::multimap<ValuePair, ValuePair> &PairableInstUserMap, 306 DenseMap<Value *, Value *> &ChosenPairs, 307 DenseMap<ValuePair, size_t> &Tree, 308 DenseSet<ValuePair> &PrunedTree, ValuePair J, 309 bool UseCycleCheck); 310 311 void buildInitialTreeFor( 312 std::multimap<Value *, Value *> &CandidatePairs, 313 std::vector<Value *> &PairableInsts, 314 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 315 DenseSet<ValuePair> &PairableInstUsers, 316 DenseMap<Value *, Value *> &ChosenPairs, 317 DenseMap<ValuePair, size_t> &Tree, ValuePair J); 318 319 void findBestTreeFor( 320 std::multimap<Value *, Value *> &CandidatePairs, 321 DenseMap<ValuePair, int> &CandidatePairCostSavings, 322 std::vector<Value *> &PairableInsts, 323 DenseSet<ValuePair> &FixedOrderPairs, 324 DenseMap<VPPair, unsigned> &PairConnectionTypes, 325 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 326 std::multimap<ValuePair, ValuePair> &ConnectedPairDeps, 327 DenseSet<ValuePair> &PairableInstUsers, 328 std::multimap<ValuePair, ValuePair> &PairableInstUserMap, 329 DenseMap<Value *, Value *> &ChosenPairs, 330 DenseSet<ValuePair> &BestTree, size_t &BestMaxDepth, 331 int &BestEffSize, VPIteratorPair ChoiceRange, 332 bool UseCycleCheck); 333 334 Value *getReplacementPointerInput(LLVMContext& Context, Instruction *I, 335 Instruction *J, unsigned o); 336 337 void fillNewShuffleMask(LLVMContext& Context, Instruction *J, 338 unsigned MaskOffset, unsigned NumInElem, 339 unsigned NumInElem1, unsigned IdxOffset, 340 std::vector<Constant*> &Mask); 341 342 Value *getReplacementShuffleMask(LLVMContext& Context, Instruction *I, 343 Instruction *J); 344 345 bool expandIEChain(LLVMContext& Context, Instruction *I, Instruction *J, 346 unsigned o, Value *&LOp, unsigned numElemL, 347 Type *ArgTypeL, Type *ArgTypeR, bool IBeforeJ, 348 unsigned IdxOff = 0); 349 350 Value *getReplacementInput(LLVMContext& Context, Instruction *I, 351 Instruction *J, unsigned o, bool IBeforeJ); 352 353 void getReplacementInputsForPair(LLVMContext& Context, Instruction *I, 354 Instruction *J, SmallVector<Value *, 3> &ReplacedOperands, 355 bool IBeforeJ); 356 357 void replaceOutputsOfPair(LLVMContext& Context, Instruction *I, 358 Instruction *J, Instruction *K, 359 Instruction *&InsertionPt, Instruction *&K1, 360 Instruction *&K2); 361 362 void collectPairLoadMoveSet(BasicBlock &BB, 363 DenseMap<Value *, Value *> &ChosenPairs, 364 std::multimap<Value *, Value *> &LoadMoveSet, 365 Instruction *I); 366 367 void collectLoadMoveSet(BasicBlock &BB, 368 std::vector<Value *> &PairableInsts, 369 DenseMap<Value *, Value *> &ChosenPairs, 370 std::multimap<Value *, Value *> &LoadMoveSet); 371 372 bool canMoveUsesOfIAfterJ(BasicBlock &BB, 373 std::multimap<Value *, Value *> &LoadMoveSet, 374 Instruction *I, Instruction *J); 375 376 void moveUsesOfIAfterJ(BasicBlock &BB, 377 std::multimap<Value *, Value *> &LoadMoveSet, 378 Instruction *&InsertionPt, 379 Instruction *I, Instruction *J); 380 381 void combineMetadata(Instruction *K, const Instruction *J); 382 383 bool vectorizeBB(BasicBlock &BB) { 384 if (!DT->isReachableFromEntry(&BB)) { 385 DEBUG(dbgs() << "BBV: skipping unreachable " << BB.getName() << 386 " in " << BB.getParent()->getName() << "\n"); 387 return false; 388 } 389 390 DEBUG(if (VTTI) dbgs() << "BBV: using target information\n"); 391 392 bool changed = false; 393 // Iterate a sufficient number of times to merge types of size 1 bit, 394 // then 2 bits, then 4, etc. up to half of the target vector width of the 395 // target vector register. 396 unsigned n = 1; 397 for (unsigned v = 2; 398 (VTTI || v <= Config.VectorBits) && 399 (!Config.MaxIter || n <= Config.MaxIter); 400 v *= 2, ++n) { 401 DEBUG(dbgs() << "BBV: fusing loop #" << n << 402 " for " << BB.getName() << " in " << 403 BB.getParent()->getName() << "...\n"); 404 if (vectorizePairs(BB)) 405 changed = true; 406 else 407 break; 408 } 409 410 if (changed && !Pow2LenOnly) { 411 ++n; 412 for (; !Config.MaxIter || n <= Config.MaxIter; ++n) { 413 DEBUG(dbgs() << "BBV: fusing for non-2^n-length vectors loop #: " << 414 n << " for " << BB.getName() << " in " << 415 BB.getParent()->getName() << "...\n"); 416 if (!vectorizePairs(BB, true)) break; 417 } 418 } 419 420 DEBUG(dbgs() << "BBV: done!\n"); 421 return changed; 422 } 423 424 virtual bool runOnBasicBlock(BasicBlock &BB) { 425 AA = &getAnalysis<AliasAnalysis>(); 426 DT = &getAnalysis<DominatorTree>(); 427 SE = &getAnalysis<ScalarEvolution>(); 428 TD = getAnalysisIfAvailable<DataLayout>(); 429 TTI = IgnoreTargetInfo ? 0 : 430 getAnalysisIfAvailable<TargetTransformInfo>(); 431 VTTI = TTI ? TTI->getVectorTargetTransformInfo() : 0; 432 433 return vectorizeBB(BB); 434 } 435 436 virtual void getAnalysisUsage(AnalysisUsage &AU) const { 437 BasicBlockPass::getAnalysisUsage(AU); 438 AU.addRequired<AliasAnalysis>(); 439 AU.addRequired<DominatorTree>(); 440 AU.addRequired<ScalarEvolution>(); 441 AU.addPreserved<AliasAnalysis>(); 442 AU.addPreserved<DominatorTree>(); 443 AU.addPreserved<ScalarEvolution>(); 444 AU.setPreservesCFG(); 445 } 446 447 static inline VectorType *getVecTypeForPair(Type *ElemTy, Type *Elem2Ty) { 448 assert(ElemTy->getScalarType() == Elem2Ty->getScalarType() && 449 "Cannot form vector from incompatible scalar types"); 450 Type *STy = ElemTy->getScalarType(); 451 452 unsigned numElem; 453 if (VectorType *VTy = dyn_cast<VectorType>(ElemTy)) { 454 numElem = VTy->getNumElements(); 455 } else { 456 numElem = 1; 457 } 458 459 if (VectorType *VTy = dyn_cast<VectorType>(Elem2Ty)) { 460 numElem += VTy->getNumElements(); 461 } else { 462 numElem += 1; 463 } 464 465 return VectorType::get(STy, numElem); 466 } 467 468 static inline void getInstructionTypes(Instruction *I, 469 Type *&T1, Type *&T2) { 470 if (isa<StoreInst>(I)) { 471 // For stores, it is the value type, not the pointer type that matters 472 // because the value is what will come from a vector register. 473 474 Value *IVal = cast<StoreInst>(I)->getValueOperand(); 475 T1 = IVal->getType(); 476 } else { 477 T1 = I->getType(); 478 } 479 480 if (I->isCast()) 481 T2 = cast<CastInst>(I)->getSrcTy(); 482 else 483 T2 = T1; 484 485 if (SelectInst *SI = dyn_cast<SelectInst>(I)) { 486 T2 = SI->getCondition()->getType(); 487 } else if (ShuffleVectorInst *SI = dyn_cast<ShuffleVectorInst>(I)) { 488 T2 = SI->getOperand(0)->getType(); 489 } else if (CmpInst *CI = dyn_cast<CmpInst>(I)) { 490 T2 = CI->getOperand(0)->getType(); 491 } 492 } 493 494 // Returns the weight associated with the provided value. A chain of 495 // candidate pairs has a length given by the sum of the weights of its 496 // members (one weight per pair; the weight of each member of the pair 497 // is assumed to be the same). This length is then compared to the 498 // chain-length threshold to determine if a given chain is significant 499 // enough to be vectorized. The length is also used in comparing 500 // candidate chains where longer chains are considered to be better. 501 // Note: when this function returns 0, the resulting instructions are 502 // not actually fused. 503 inline size_t getDepthFactor(Value *V) { 504 // InsertElement and ExtractElement have a depth factor of zero. This is 505 // for two reasons: First, they cannot be usefully fused. Second, because 506 // the pass generates a lot of these, they can confuse the simple metric 507 // used to compare the trees in the next iteration. Thus, giving them a 508 // weight of zero allows the pass to essentially ignore them in 509 // subsequent iterations when looking for vectorization opportunities 510 // while still tracking dependency chains that flow through those 511 // instructions. 512 if (isa<InsertElementInst>(V) || isa<ExtractElementInst>(V)) 513 return 0; 514 515 // Give a load or store half of the required depth so that load/store 516 // pairs will vectorize. 517 if (!Config.NoMemOpBoost && (isa<LoadInst>(V) || isa<StoreInst>(V))) 518 return Config.ReqChainDepth/2; 519 520 return 1; 521 } 522 523 // Returns the cost of the provided instruction using VTTI. 524 // This does not handle loads and stores. 525 unsigned getInstrCost(unsigned Opcode, Type *T1, Type *T2) { 526 switch (Opcode) { 527 default: break; 528 case Instruction::GetElementPtr: 529 // We mark this instruction as zero-cost because scalar GEPs are usually 530 // lowered to the intruction addressing mode. At the moment we don't 531 // generate vector GEPs. 532 return 0; 533 case Instruction::Br: 534 return VTTI->getCFInstrCost(Opcode); 535 case Instruction::PHI: 536 return 0; 537 case Instruction::Add: 538 case Instruction::FAdd: 539 case Instruction::Sub: 540 case Instruction::FSub: 541 case Instruction::Mul: 542 case Instruction::FMul: 543 case Instruction::UDiv: 544 case Instruction::SDiv: 545 case Instruction::FDiv: 546 case Instruction::URem: 547 case Instruction::SRem: 548 case Instruction::FRem: 549 case Instruction::Shl: 550 case Instruction::LShr: 551 case Instruction::AShr: 552 case Instruction::And: 553 case Instruction::Or: 554 case Instruction::Xor: 555 return VTTI->getArithmeticInstrCost(Opcode, T1); 556 case Instruction::Select: 557 case Instruction::ICmp: 558 case Instruction::FCmp: 559 return VTTI->getCmpSelInstrCost(Opcode, T1, T2); 560 case Instruction::ZExt: 561 case Instruction::SExt: 562 case Instruction::FPToUI: 563 case Instruction::FPToSI: 564 case Instruction::FPExt: 565 case Instruction::PtrToInt: 566 case Instruction::IntToPtr: 567 case Instruction::SIToFP: 568 case Instruction::UIToFP: 569 case Instruction::Trunc: 570 case Instruction::FPTrunc: 571 case Instruction::BitCast: 572 case Instruction::ShuffleVector: 573 return VTTI->getCastInstrCost(Opcode, T1, T2); 574 } 575 576 return 1; 577 } 578 579 // This determines the relative offset of two loads or stores, returning 580 // true if the offset could be determined to be some constant value. 581 // For example, if OffsetInElmts == 1, then J accesses the memory directly 582 // after I; if OffsetInElmts == -1 then I accesses the memory 583 // directly after J. 584 bool getPairPtrInfo(Instruction *I, Instruction *J, 585 Value *&IPtr, Value *&JPtr, unsigned &IAlignment, unsigned &JAlignment, 586 unsigned &IAddressSpace, unsigned &JAddressSpace, 587 int64_t &OffsetInElmts, bool ComputeOffset = true) { 588 OffsetInElmts = 0; 589 if (LoadInst *LI = dyn_cast<LoadInst>(I)) { 590 LoadInst *LJ = cast<LoadInst>(J); 591 IPtr = LI->getPointerOperand(); 592 JPtr = LJ->getPointerOperand(); 593 IAlignment = LI->getAlignment(); 594 JAlignment = LJ->getAlignment(); 595 IAddressSpace = LI->getPointerAddressSpace(); 596 JAddressSpace = LJ->getPointerAddressSpace(); 597 } else { 598 StoreInst *SI = cast<StoreInst>(I), *SJ = cast<StoreInst>(J); 599 IPtr = SI->getPointerOperand(); 600 JPtr = SJ->getPointerOperand(); 601 IAlignment = SI->getAlignment(); 602 JAlignment = SJ->getAlignment(); 603 IAddressSpace = SI->getPointerAddressSpace(); 604 JAddressSpace = SJ->getPointerAddressSpace(); 605 } 606 607 if (!ComputeOffset) 608 return true; 609 610 const SCEV *IPtrSCEV = SE->getSCEV(IPtr); 611 const SCEV *JPtrSCEV = SE->getSCEV(JPtr); 612 613 // If this is a trivial offset, then we'll get something like 614 // 1*sizeof(type). With target data, which we need anyway, this will get 615 // constant folded into a number. 616 const SCEV *OffsetSCEV = SE->getMinusSCEV(JPtrSCEV, IPtrSCEV); 617 if (const SCEVConstant *ConstOffSCEV = 618 dyn_cast<SCEVConstant>(OffsetSCEV)) { 619 ConstantInt *IntOff = ConstOffSCEV->getValue(); 620 int64_t Offset = IntOff->getSExtValue(); 621 622 Type *VTy = cast<PointerType>(IPtr->getType())->getElementType(); 623 int64_t VTyTSS = (int64_t) TD->getTypeStoreSize(VTy); 624 625 Type *VTy2 = cast<PointerType>(JPtr->getType())->getElementType(); 626 if (VTy != VTy2 && Offset < 0) { 627 int64_t VTy2TSS = (int64_t) TD->getTypeStoreSize(VTy2); 628 OffsetInElmts = Offset/VTy2TSS; 629 return (abs64(Offset) % VTy2TSS) == 0; 630 } 631 632 OffsetInElmts = Offset/VTyTSS; 633 return (abs64(Offset) % VTyTSS) == 0; 634 } 635 636 return false; 637 } 638 639 // Returns true if the provided CallInst represents an intrinsic that can 640 // be vectorized. 641 bool isVectorizableIntrinsic(CallInst* I) { 642 Function *F = I->getCalledFunction(); 643 if (!F) return false; 644 645 unsigned IID = F->getIntrinsicID(); 646 if (!IID) return false; 647 648 switch(IID) { 649 default: 650 return false; 651 case Intrinsic::sqrt: 652 case Intrinsic::powi: 653 case Intrinsic::sin: 654 case Intrinsic::cos: 655 case Intrinsic::log: 656 case Intrinsic::log2: 657 case Intrinsic::log10: 658 case Intrinsic::exp: 659 case Intrinsic::exp2: 660 case Intrinsic::pow: 661 return Config.VectorizeMath; 662 case Intrinsic::fma: 663 return Config.VectorizeFMA; 664 } 665 } 666 667 // Returns true if J is the second element in some pair referenced by 668 // some multimap pair iterator pair. 669 template <typename V> 670 bool isSecondInIteratorPair(V J, std::pair< 671 typename std::multimap<V, V>::iterator, 672 typename std::multimap<V, V>::iterator> PairRange) { 673 for (typename std::multimap<V, V>::iterator K = PairRange.first; 674 K != PairRange.second; ++K) 675 if (K->second == J) return true; 676 677 return false; 678 } 679 680 bool isPureIEChain(InsertElementInst *IE) { 681 InsertElementInst *IENext = IE; 682 do { 683 if (!isa<UndefValue>(IENext->getOperand(0)) && 684 !isa<InsertElementInst>(IENext->getOperand(0))) { 685 return false; 686 } 687 } while ((IENext = 688 dyn_cast<InsertElementInst>(IENext->getOperand(0)))); 689 690 return true; 691 } 692 }; 693 694 // This function implements one vectorization iteration on the provided 695 // basic block. It returns true if the block is changed. 696 bool BBVectorize::vectorizePairs(BasicBlock &BB, bool NonPow2Len) { 697 bool ShouldContinue; 698 BasicBlock::iterator Start = BB.getFirstInsertionPt(); 699 700 std::vector<Value *> AllPairableInsts; 701 DenseMap<Value *, Value *> AllChosenPairs; 702 DenseSet<ValuePair> AllFixedOrderPairs; 703 DenseMap<VPPair, unsigned> AllPairConnectionTypes; 704 std::multimap<ValuePair, ValuePair> AllConnectedPairs, AllConnectedPairDeps; 705 706 do { 707 std::vector<Value *> PairableInsts; 708 std::multimap<Value *, Value *> CandidatePairs; 709 DenseSet<ValuePair> FixedOrderPairs; 710 DenseMap<ValuePair, int> CandidatePairCostSavings; 711 ShouldContinue = getCandidatePairs(BB, Start, CandidatePairs, 712 FixedOrderPairs, 713 CandidatePairCostSavings, 714 PairableInsts, NonPow2Len); 715 if (PairableInsts.empty()) continue; 716 717 // Now we have a map of all of the pairable instructions and we need to 718 // select the best possible pairing. A good pairing is one such that the 719 // users of the pair are also paired. This defines a (directed) forest 720 // over the pairs such that two pairs are connected iff the second pair 721 // uses the first. 722 723 // Note that it only matters that both members of the second pair use some 724 // element of the first pair (to allow for splatting). 725 726 std::multimap<ValuePair, ValuePair> ConnectedPairs, ConnectedPairDeps; 727 DenseMap<VPPair, unsigned> PairConnectionTypes; 728 computeConnectedPairs(CandidatePairs, PairableInsts, ConnectedPairs, 729 PairConnectionTypes); 730 if (ConnectedPairs.empty()) continue; 731 732 for (std::multimap<ValuePair, ValuePair>::iterator 733 I = ConnectedPairs.begin(), IE = ConnectedPairs.end(); 734 I != IE; ++I) { 735 ConnectedPairDeps.insert(VPPair(I->second, I->first)); 736 } 737 738 // Build the pairable-instruction dependency map 739 DenseSet<ValuePair> PairableInstUsers; 740 buildDepMap(BB, CandidatePairs, PairableInsts, PairableInstUsers); 741 742 // There is now a graph of the connected pairs. For each variable, pick 743 // the pairing with the largest tree meeting the depth requirement on at 744 // least one branch. Then select all pairings that are part of that tree 745 // and remove them from the list of available pairings and pairable 746 // variables. 747 748 DenseMap<Value *, Value *> ChosenPairs; 749 choosePairs(CandidatePairs, CandidatePairCostSavings, 750 PairableInsts, FixedOrderPairs, PairConnectionTypes, 751 ConnectedPairs, ConnectedPairDeps, 752 PairableInstUsers, ChosenPairs); 753 754 if (ChosenPairs.empty()) continue; 755 AllPairableInsts.insert(AllPairableInsts.end(), PairableInsts.begin(), 756 PairableInsts.end()); 757 AllChosenPairs.insert(ChosenPairs.begin(), ChosenPairs.end()); 758 759 // Only for the chosen pairs, propagate information on fixed-order pairs, 760 // pair connections, and their types to the data structures used by the 761 // pair fusion procedures. 762 for (DenseMap<Value *, Value *>::iterator I = ChosenPairs.begin(), 763 IE = ChosenPairs.end(); I != IE; ++I) { 764 if (FixedOrderPairs.count(*I)) 765 AllFixedOrderPairs.insert(*I); 766 else if (FixedOrderPairs.count(ValuePair(I->second, I->first))) 767 AllFixedOrderPairs.insert(ValuePair(I->second, I->first)); 768 769 for (DenseMap<Value *, Value *>::iterator J = ChosenPairs.begin(); 770 J != IE; ++J) { 771 DenseMap<VPPair, unsigned>::iterator K = 772 PairConnectionTypes.find(VPPair(*I, *J)); 773 if (K != PairConnectionTypes.end()) { 774 AllPairConnectionTypes.insert(*K); 775 } else { 776 K = PairConnectionTypes.find(VPPair(*J, *I)); 777 if (K != PairConnectionTypes.end()) 778 AllPairConnectionTypes.insert(*K); 779 } 780 } 781 } 782 783 for (std::multimap<ValuePair, ValuePair>::iterator 784 I = ConnectedPairs.begin(), IE = ConnectedPairs.end(); 785 I != IE; ++I) { 786 if (AllPairConnectionTypes.count(*I)) { 787 AllConnectedPairs.insert(*I); 788 AllConnectedPairDeps.insert(VPPair(I->second, I->first)); 789 } 790 } 791 } while (ShouldContinue); 792 793 if (AllChosenPairs.empty()) return false; 794 NumFusedOps += AllChosenPairs.size(); 795 796 // A set of pairs has now been selected. It is now necessary to replace the 797 // paired instructions with vector instructions. For this procedure each 798 // operand must be replaced with a vector operand. This vector is formed 799 // by using build_vector on the old operands. The replaced values are then 800 // replaced with a vector_extract on the result. Subsequent optimization 801 // passes should coalesce the build/extract combinations. 802 803 fuseChosenPairs(BB, AllPairableInsts, AllChosenPairs, AllFixedOrderPairs, 804 AllPairConnectionTypes, 805 AllConnectedPairs, AllConnectedPairDeps); 806 807 // It is important to cleanup here so that future iterations of this 808 // function have less work to do. 809 (void) SimplifyInstructionsInBlock(&BB, TD, AA->getTargetLibraryInfo()); 810 return true; 811 } 812 813 // This function returns true if the provided instruction is capable of being 814 // fused into a vector instruction. This determination is based only on the 815 // type and other attributes of the instruction. 816 bool BBVectorize::isInstVectorizable(Instruction *I, 817 bool &IsSimpleLoadStore) { 818 IsSimpleLoadStore = false; 819 820 if (CallInst *C = dyn_cast<CallInst>(I)) { 821 if (!isVectorizableIntrinsic(C)) 822 return false; 823 } else if (LoadInst *L = dyn_cast<LoadInst>(I)) { 824 // Vectorize simple loads if possbile: 825 IsSimpleLoadStore = L->isSimple(); 826 if (!IsSimpleLoadStore || !Config.VectorizeMemOps) 827 return false; 828 } else if (StoreInst *S = dyn_cast<StoreInst>(I)) { 829 // Vectorize simple stores if possbile: 830 IsSimpleLoadStore = S->isSimple(); 831 if (!IsSimpleLoadStore || !Config.VectorizeMemOps) 832 return false; 833 } else if (CastInst *C = dyn_cast<CastInst>(I)) { 834 // We can vectorize casts, but not casts of pointer types, etc. 835 if (!Config.VectorizeCasts) 836 return false; 837 838 Type *SrcTy = C->getSrcTy(); 839 if (!SrcTy->isSingleValueType()) 840 return false; 841 842 Type *DestTy = C->getDestTy(); 843 if (!DestTy->isSingleValueType()) 844 return false; 845 } else if (isa<SelectInst>(I)) { 846 if (!Config.VectorizeSelect) 847 return false; 848 } else if (isa<CmpInst>(I)) { 849 if (!Config.VectorizeCmp) 850 return false; 851 } else if (GetElementPtrInst *G = dyn_cast<GetElementPtrInst>(I)) { 852 if (!Config.VectorizeGEP) 853 return false; 854 855 // Currently, vector GEPs exist only with one index. 856 if (G->getNumIndices() != 1) 857 return false; 858 } else if (!(I->isBinaryOp() || isa<ShuffleVectorInst>(I) || 859 isa<ExtractElementInst>(I) || isa<InsertElementInst>(I))) { 860 return false; 861 } 862 863 // We can't vectorize memory operations without target data 864 if (TD == 0 && IsSimpleLoadStore) 865 return false; 866 867 Type *T1, *T2; 868 getInstructionTypes(I, T1, T2); 869 870 // Not every type can be vectorized... 871 if (!(VectorType::isValidElementType(T1) || T1->isVectorTy()) || 872 !(VectorType::isValidElementType(T2) || T2->isVectorTy())) 873 return false; 874 875 if (T1->getScalarSizeInBits() == 1) { 876 if (!Config.VectorizeBools) 877 return false; 878 } else { 879 if (!Config.VectorizeInts && T1->isIntOrIntVectorTy()) 880 return false; 881 } 882 883 if (T2->getScalarSizeInBits() == 1) { 884 if (!Config.VectorizeBools) 885 return false; 886 } else { 887 if (!Config.VectorizeInts && T2->isIntOrIntVectorTy()) 888 return false; 889 } 890 891 if (!Config.VectorizeFloats 892 && (T1->isFPOrFPVectorTy() || T2->isFPOrFPVectorTy())) 893 return false; 894 895 // Don't vectorize target-specific types. 896 if (T1->isX86_FP80Ty() || T1->isPPC_FP128Ty() || T1->isX86_MMXTy()) 897 return false; 898 if (T2->isX86_FP80Ty() || T2->isPPC_FP128Ty() || T2->isX86_MMXTy()) 899 return false; 900 901 if ((!Config.VectorizePointers || TD == 0) && 902 (T1->getScalarType()->isPointerTy() || 903 T2->getScalarType()->isPointerTy())) 904 return false; 905 906 if (!VTTI && (T1->getPrimitiveSizeInBits() >= Config.VectorBits || 907 T2->getPrimitiveSizeInBits() >= Config.VectorBits)) 908 return false; 909 910 return true; 911 } 912 913 // This function returns true if the two provided instructions are compatible 914 // (meaning that they can be fused into a vector instruction). This assumes 915 // that I has already been determined to be vectorizable and that J is not 916 // in the use tree of I. 917 bool BBVectorize::areInstsCompatible(Instruction *I, Instruction *J, 918 bool IsSimpleLoadStore, bool NonPow2Len, 919 int &CostSavings, int &FixedOrder) { 920 DEBUG(if (DebugInstructionExamination) dbgs() << "BBV: looking at " << *I << 921 " <-> " << *J << "\n"); 922 923 CostSavings = 0; 924 FixedOrder = 0; 925 926 // Loads and stores can be merged if they have different alignments, 927 // but are otherwise the same. 928 if (!J->isSameOperationAs(I, Instruction::CompareIgnoringAlignment | 929 (NonPow2Len ? Instruction::CompareUsingScalarTypes : 0))) 930 return false; 931 932 Type *IT1, *IT2, *JT1, *JT2; 933 getInstructionTypes(I, IT1, IT2); 934 getInstructionTypes(J, JT1, JT2); 935 unsigned MaxTypeBits = std::max( 936 IT1->getPrimitiveSizeInBits() + JT1->getPrimitiveSizeInBits(), 937 IT2->getPrimitiveSizeInBits() + JT2->getPrimitiveSizeInBits()); 938 if (!VTTI && MaxTypeBits > Config.VectorBits) 939 return false; 940 941 // FIXME: handle addsub-type operations! 942 943 if (IsSimpleLoadStore) { 944 Value *IPtr, *JPtr; 945 unsigned IAlignment, JAlignment, IAddressSpace, JAddressSpace; 946 int64_t OffsetInElmts = 0; 947 if (getPairPtrInfo(I, J, IPtr, JPtr, IAlignment, JAlignment, 948 IAddressSpace, JAddressSpace, 949 OffsetInElmts) && abs64(OffsetInElmts) == 1) { 950 FixedOrder = (int) OffsetInElmts; 951 unsigned BottomAlignment = IAlignment; 952 if (OffsetInElmts < 0) BottomAlignment = JAlignment; 953 954 Type *aTypeI = isa<StoreInst>(I) ? 955 cast<StoreInst>(I)->getValueOperand()->getType() : I->getType(); 956 Type *aTypeJ = isa<StoreInst>(J) ? 957 cast<StoreInst>(J)->getValueOperand()->getType() : J->getType(); 958 Type *VType = getVecTypeForPair(aTypeI, aTypeJ); 959 960 if (Config.AlignedOnly) { 961 // An aligned load or store is possible only if the instruction 962 // with the lower offset has an alignment suitable for the 963 // vector type. 964 965 unsigned VecAlignment = TD->getPrefTypeAlignment(VType); 966 if (BottomAlignment < VecAlignment) 967 return false; 968 } 969 970 if (VTTI) { 971 unsigned ICost = VTTI->getMemoryOpCost(I->getOpcode(), I->getType(), 972 IAlignment, IAddressSpace); 973 unsigned JCost = VTTI->getMemoryOpCost(J->getOpcode(), J->getType(), 974 JAlignment, JAddressSpace); 975 unsigned VCost = VTTI->getMemoryOpCost(I->getOpcode(), VType, 976 BottomAlignment, 977 IAddressSpace); 978 if (VCost > ICost + JCost) 979 return false; 980 981 // We don't want to fuse to a type that will be split, even 982 // if the two input types will also be split and there is no other 983 // associated cost. 984 unsigned VParts = VTTI->getNumberOfParts(VType); 985 if (VParts > 1) 986 return false; 987 else if (!VParts && VCost == ICost + JCost) 988 return false; 989 990 CostSavings = ICost + JCost - VCost; 991 } 992 } else { 993 return false; 994 } 995 } else if (VTTI) { 996 unsigned ICost = getInstrCost(I->getOpcode(), IT1, IT2); 997 unsigned JCost = getInstrCost(J->getOpcode(), JT1, JT2); 998 Type *VT1 = getVecTypeForPair(IT1, JT1), 999 *VT2 = getVecTypeForPair(IT2, JT2); 1000 unsigned VCost = getInstrCost(I->getOpcode(), VT1, VT2); 1001 1002 if (VCost > ICost + JCost) 1003 return false; 1004 1005 // We don't want to fuse to a type that will be split, even 1006 // if the two input types will also be split and there is no other 1007 // associated cost. 1008 unsigned VParts1 = VTTI->getNumberOfParts(VT1), 1009 VParts2 = VTTI->getNumberOfParts(VT2); 1010 if (VParts1 > 1 || VParts2 > 1) 1011 return false; 1012 else if ((!VParts1 || !VParts2) && VCost == ICost + JCost) 1013 return false; 1014 1015 CostSavings = ICost + JCost - VCost; 1016 } 1017 1018 // The powi intrinsic is special because only the first argument is 1019 // vectorized, the second arguments must be equal. 1020 CallInst *CI = dyn_cast<CallInst>(I); 1021 Function *FI; 1022 if (CI && (FI = CI->getCalledFunction()) && 1023 FI->getIntrinsicID() == Intrinsic::powi) { 1024 1025 Value *A1I = CI->getArgOperand(1), 1026 *A1J = cast<CallInst>(J)->getArgOperand(1); 1027 const SCEV *A1ISCEV = SE->getSCEV(A1I), 1028 *A1JSCEV = SE->getSCEV(A1J); 1029 return (A1ISCEV == A1JSCEV); 1030 } 1031 1032 return true; 1033 } 1034 1035 // Figure out whether or not J uses I and update the users and write-set 1036 // structures associated with I. Specifically, Users represents the set of 1037 // instructions that depend on I. WriteSet represents the set 1038 // of memory locations that are dependent on I. If UpdateUsers is true, 1039 // and J uses I, then Users is updated to contain J and WriteSet is updated 1040 // to contain any memory locations to which J writes. The function returns 1041 // true if J uses I. By default, alias analysis is used to determine 1042 // whether J reads from memory that overlaps with a location in WriteSet. 1043 // If LoadMoveSet is not null, then it is a previously-computed multimap 1044 // where the key is the memory-based user instruction and the value is 1045 // the instruction to be compared with I. So, if LoadMoveSet is provided, 1046 // then the alias analysis is not used. This is necessary because this 1047 // function is called during the process of moving instructions during 1048 // vectorization and the results of the alias analysis are not stable during 1049 // that process. 1050 bool BBVectorize::trackUsesOfI(DenseSet<Value *> &Users, 1051 AliasSetTracker &WriteSet, Instruction *I, 1052 Instruction *J, bool UpdateUsers, 1053 std::multimap<Value *, Value *> *LoadMoveSet) { 1054 bool UsesI = false; 1055 1056 // This instruction may already be marked as a user due, for example, to 1057 // being a member of a selected pair. 1058 if (Users.count(J)) 1059 UsesI = true; 1060 1061 if (!UsesI) 1062 for (User::op_iterator JU = J->op_begin(), JE = J->op_end(); 1063 JU != JE; ++JU) { 1064 Value *V = *JU; 1065 if (I == V || Users.count(V)) { 1066 UsesI = true; 1067 break; 1068 } 1069 } 1070 if (!UsesI && J->mayReadFromMemory()) { 1071 if (LoadMoveSet) { 1072 VPIteratorPair JPairRange = LoadMoveSet->equal_range(J); 1073 UsesI = isSecondInIteratorPair<Value*>(I, JPairRange); 1074 } else { 1075 for (AliasSetTracker::iterator W = WriteSet.begin(), 1076 WE = WriteSet.end(); W != WE; ++W) { 1077 if (W->aliasesUnknownInst(J, *AA)) { 1078 UsesI = true; 1079 break; 1080 } 1081 } 1082 } 1083 } 1084 1085 if (UsesI && UpdateUsers) { 1086 if (J->mayWriteToMemory()) WriteSet.add(J); 1087 Users.insert(J); 1088 } 1089 1090 return UsesI; 1091 } 1092 1093 // This function iterates over all instruction pairs in the provided 1094 // basic block and collects all candidate pairs for vectorization. 1095 bool BBVectorize::getCandidatePairs(BasicBlock &BB, 1096 BasicBlock::iterator &Start, 1097 std::multimap<Value *, Value *> &CandidatePairs, 1098 DenseSet<ValuePair> &FixedOrderPairs, 1099 DenseMap<ValuePair, int> &CandidatePairCostSavings, 1100 std::vector<Value *> &PairableInsts, bool NonPow2Len) { 1101 BasicBlock::iterator E = BB.end(); 1102 if (Start == E) return false; 1103 1104 bool ShouldContinue = false, IAfterStart = false; 1105 for (BasicBlock::iterator I = Start++; I != E; ++I) { 1106 if (I == Start) IAfterStart = true; 1107 1108 bool IsSimpleLoadStore; 1109 if (!isInstVectorizable(I, IsSimpleLoadStore)) continue; 1110 1111 // Look for an instruction with which to pair instruction *I... 1112 DenseSet<Value *> Users; 1113 AliasSetTracker WriteSet(*AA); 1114 bool JAfterStart = IAfterStart; 1115 BasicBlock::iterator J = llvm::next(I); 1116 for (unsigned ss = 0; J != E && ss <= Config.SearchLimit; ++J, ++ss) { 1117 if (J == Start) JAfterStart = true; 1118 1119 // Determine if J uses I, if so, exit the loop. 1120 bool UsesI = trackUsesOfI(Users, WriteSet, I, J, !Config.FastDep); 1121 if (Config.FastDep) { 1122 // Note: For this heuristic to be effective, independent operations 1123 // must tend to be intermixed. This is likely to be true from some 1124 // kinds of grouped loop unrolling (but not the generic LLVM pass), 1125 // but otherwise may require some kind of reordering pass. 1126 1127 // When using fast dependency analysis, 1128 // stop searching after first use: 1129 if (UsesI) break; 1130 } else { 1131 if (UsesI) continue; 1132 } 1133 1134 // J does not use I, and comes before the first use of I, so it can be 1135 // merged with I if the instructions are compatible. 1136 int CostSavings, FixedOrder; 1137 if (!areInstsCompatible(I, J, IsSimpleLoadStore, NonPow2Len, 1138 CostSavings, FixedOrder)) continue; 1139 1140 // J is a candidate for merging with I. 1141 if (!PairableInsts.size() || 1142 PairableInsts[PairableInsts.size()-1] != I) { 1143 PairableInsts.push_back(I); 1144 } 1145 1146 CandidatePairs.insert(ValuePair(I, J)); 1147 if (VTTI) 1148 CandidatePairCostSavings.insert(ValuePairWithCost(ValuePair(I, J), 1149 CostSavings)); 1150 1151 if (FixedOrder == 1) 1152 FixedOrderPairs.insert(ValuePair(I, J)); 1153 else if (FixedOrder == -1) 1154 FixedOrderPairs.insert(ValuePair(J, I)); 1155 1156 // The next call to this function must start after the last instruction 1157 // selected during this invocation. 1158 if (JAfterStart) { 1159 Start = llvm::next(J); 1160 IAfterStart = JAfterStart = false; 1161 } 1162 1163 DEBUG(if (DebugCandidateSelection) dbgs() << "BBV: candidate pair " 1164 << *I << " <-> " << *J << " (cost savings: " << 1165 CostSavings << ")\n"); 1166 1167 // If we have already found too many pairs, break here and this function 1168 // will be called again starting after the last instruction selected 1169 // during this invocation. 1170 if (PairableInsts.size() >= Config.MaxInsts) { 1171 ShouldContinue = true; 1172 break; 1173 } 1174 } 1175 1176 if (ShouldContinue) 1177 break; 1178 } 1179 1180 DEBUG(dbgs() << "BBV: found " << PairableInsts.size() 1181 << " instructions with candidate pairs\n"); 1182 1183 return ShouldContinue; 1184 } 1185 1186 // Finds candidate pairs connected to the pair P = <PI, PJ>. This means that 1187 // it looks for pairs such that both members have an input which is an 1188 // output of PI or PJ. 1189 void BBVectorize::computePairsConnectedTo( 1190 std::multimap<Value *, Value *> &CandidatePairs, 1191 std::vector<Value *> &PairableInsts, 1192 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 1193 DenseMap<VPPair, unsigned> &PairConnectionTypes, 1194 ValuePair P) { 1195 StoreInst *SI, *SJ; 1196 1197 // For each possible pairing for this variable, look at the uses of 1198 // the first value... 1199 for (Value::use_iterator I = P.first->use_begin(), 1200 E = P.first->use_end(); I != E; ++I) { 1201 if (isa<LoadInst>(*I)) { 1202 // A pair cannot be connected to a load because the load only takes one 1203 // operand (the address) and it is a scalar even after vectorization. 1204 continue; 1205 } else if ((SI = dyn_cast<StoreInst>(*I)) && 1206 P.first == SI->getPointerOperand()) { 1207 // Similarly, a pair cannot be connected to a store through its 1208 // pointer operand. 1209 continue; 1210 } 1211 1212 VPIteratorPair IPairRange = CandidatePairs.equal_range(*I); 1213 1214 // For each use of the first variable, look for uses of the second 1215 // variable... 1216 for (Value::use_iterator J = P.second->use_begin(), 1217 E2 = P.second->use_end(); J != E2; ++J) { 1218 if ((SJ = dyn_cast<StoreInst>(*J)) && 1219 P.second == SJ->getPointerOperand()) 1220 continue; 1221 1222 VPIteratorPair JPairRange = CandidatePairs.equal_range(*J); 1223 1224 // Look for <I, J>: 1225 if (isSecondInIteratorPair<Value*>(*J, IPairRange)) { 1226 VPPair VP(P, ValuePair(*I, *J)); 1227 ConnectedPairs.insert(VP); 1228 PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionDirect)); 1229 } 1230 1231 // Look for <J, I>: 1232 if (isSecondInIteratorPair<Value*>(*I, JPairRange)) { 1233 VPPair VP(P, ValuePair(*J, *I)); 1234 ConnectedPairs.insert(VP); 1235 PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionSwap)); 1236 } 1237 } 1238 1239 if (Config.SplatBreaksChain) continue; 1240 // Look for cases where just the first value in the pair is used by 1241 // both members of another pair (splatting). 1242 for (Value::use_iterator J = P.first->use_begin(); J != E; ++J) { 1243 if ((SJ = dyn_cast<StoreInst>(*J)) && 1244 P.first == SJ->getPointerOperand()) 1245 continue; 1246 1247 if (isSecondInIteratorPair<Value*>(*J, IPairRange)) { 1248 VPPair VP(P, ValuePair(*I, *J)); 1249 ConnectedPairs.insert(VP); 1250 PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionSplat)); 1251 } 1252 } 1253 } 1254 1255 if (Config.SplatBreaksChain) return; 1256 // Look for cases where just the second value in the pair is used by 1257 // both members of another pair (splatting). 1258 for (Value::use_iterator I = P.second->use_begin(), 1259 E = P.second->use_end(); I != E; ++I) { 1260 if (isa<LoadInst>(*I)) 1261 continue; 1262 else if ((SI = dyn_cast<StoreInst>(*I)) && 1263 P.second == SI->getPointerOperand()) 1264 continue; 1265 1266 VPIteratorPair IPairRange = CandidatePairs.equal_range(*I); 1267 1268 for (Value::use_iterator J = P.second->use_begin(); J != E; ++J) { 1269 if ((SJ = dyn_cast<StoreInst>(*J)) && 1270 P.second == SJ->getPointerOperand()) 1271 continue; 1272 1273 if (isSecondInIteratorPair<Value*>(*J, IPairRange)) { 1274 VPPair VP(P, ValuePair(*I, *J)); 1275 ConnectedPairs.insert(VP); 1276 PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionSplat)); 1277 } 1278 } 1279 } 1280 } 1281 1282 // This function figures out which pairs are connected. Two pairs are 1283 // connected if some output of the first pair forms an input to both members 1284 // of the second pair. 1285 void BBVectorize::computeConnectedPairs( 1286 std::multimap<Value *, Value *> &CandidatePairs, 1287 std::vector<Value *> &PairableInsts, 1288 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 1289 DenseMap<VPPair, unsigned> &PairConnectionTypes) { 1290 1291 for (std::vector<Value *>::iterator PI = PairableInsts.begin(), 1292 PE = PairableInsts.end(); PI != PE; ++PI) { 1293 VPIteratorPair choiceRange = CandidatePairs.equal_range(*PI); 1294 1295 for (std::multimap<Value *, Value *>::iterator P = choiceRange.first; 1296 P != choiceRange.second; ++P) 1297 computePairsConnectedTo(CandidatePairs, PairableInsts, 1298 ConnectedPairs, PairConnectionTypes, *P); 1299 } 1300 1301 DEBUG(dbgs() << "BBV: found " << ConnectedPairs.size() 1302 << " pair connections.\n"); 1303 } 1304 1305 // This function builds a set of use tuples such that <A, B> is in the set 1306 // if B is in the use tree of A. If B is in the use tree of A, then B 1307 // depends on the output of A. 1308 void BBVectorize::buildDepMap( 1309 BasicBlock &BB, 1310 std::multimap<Value *, Value *> &CandidatePairs, 1311 std::vector<Value *> &PairableInsts, 1312 DenseSet<ValuePair> &PairableInstUsers) { 1313 DenseSet<Value *> IsInPair; 1314 for (std::multimap<Value *, Value *>::iterator C = CandidatePairs.begin(), 1315 E = CandidatePairs.end(); C != E; ++C) { 1316 IsInPair.insert(C->first); 1317 IsInPair.insert(C->second); 1318 } 1319 1320 // Iterate through the basic block, recording all Users of each 1321 // pairable instruction. 1322 1323 BasicBlock::iterator E = BB.end(); 1324 for (BasicBlock::iterator I = BB.getFirstInsertionPt(); I != E; ++I) { 1325 if (IsInPair.find(I) == IsInPair.end()) continue; 1326 1327 DenseSet<Value *> Users; 1328 AliasSetTracker WriteSet(*AA); 1329 for (BasicBlock::iterator J = llvm::next(I); J != E; ++J) 1330 (void) trackUsesOfI(Users, WriteSet, I, J); 1331 1332 for (DenseSet<Value *>::iterator U = Users.begin(), E = Users.end(); 1333 U != E; ++U) 1334 PairableInstUsers.insert(ValuePair(I, *U)); 1335 } 1336 } 1337 1338 // Returns true if an input to pair P is an output of pair Q and also an 1339 // input of pair Q is an output of pair P. If this is the case, then these 1340 // two pairs cannot be simultaneously fused. 1341 bool BBVectorize::pairsConflict(ValuePair P, ValuePair Q, 1342 DenseSet<ValuePair> &PairableInstUsers, 1343 std::multimap<ValuePair, ValuePair> *PairableInstUserMap) { 1344 // Two pairs are in conflict if they are mutual Users of eachother. 1345 bool QUsesP = PairableInstUsers.count(ValuePair(P.first, Q.first)) || 1346 PairableInstUsers.count(ValuePair(P.first, Q.second)) || 1347 PairableInstUsers.count(ValuePair(P.second, Q.first)) || 1348 PairableInstUsers.count(ValuePair(P.second, Q.second)); 1349 bool PUsesQ = PairableInstUsers.count(ValuePair(Q.first, P.first)) || 1350 PairableInstUsers.count(ValuePair(Q.first, P.second)) || 1351 PairableInstUsers.count(ValuePair(Q.second, P.first)) || 1352 PairableInstUsers.count(ValuePair(Q.second, P.second)); 1353 if (PairableInstUserMap) { 1354 // FIXME: The expensive part of the cycle check is not so much the cycle 1355 // check itself but this edge insertion procedure. This needs some 1356 // profiling and probably a different data structure (same is true of 1357 // most uses of std::multimap). 1358 if (PUsesQ) { 1359 VPPIteratorPair QPairRange = PairableInstUserMap->equal_range(Q); 1360 if (!isSecondInIteratorPair(P, QPairRange)) 1361 PairableInstUserMap->insert(VPPair(Q, P)); 1362 } 1363 if (QUsesP) { 1364 VPPIteratorPair PPairRange = PairableInstUserMap->equal_range(P); 1365 if (!isSecondInIteratorPair(Q, PPairRange)) 1366 PairableInstUserMap->insert(VPPair(P, Q)); 1367 } 1368 } 1369 1370 return (QUsesP && PUsesQ); 1371 } 1372 1373 // This function walks the use graph of current pairs to see if, starting 1374 // from P, the walk returns to P. 1375 bool BBVectorize::pairWillFormCycle(ValuePair P, 1376 std::multimap<ValuePair, ValuePair> &PairableInstUserMap, 1377 DenseSet<ValuePair> &CurrentPairs) { 1378 DEBUG(if (DebugCycleCheck) 1379 dbgs() << "BBV: starting cycle check for : " << *P.first << " <-> " 1380 << *P.second << "\n"); 1381 // A lookup table of visisted pairs is kept because the PairableInstUserMap 1382 // contains non-direct associations. 1383 DenseSet<ValuePair> Visited; 1384 SmallVector<ValuePair, 32> Q; 1385 // General depth-first post-order traversal: 1386 Q.push_back(P); 1387 do { 1388 ValuePair QTop = Q.pop_back_val(); 1389 Visited.insert(QTop); 1390 1391 DEBUG(if (DebugCycleCheck) 1392 dbgs() << "BBV: cycle check visiting: " << *QTop.first << " <-> " 1393 << *QTop.second << "\n"); 1394 VPPIteratorPair QPairRange = PairableInstUserMap.equal_range(QTop); 1395 for (std::multimap<ValuePair, ValuePair>::iterator C = QPairRange.first; 1396 C != QPairRange.second; ++C) { 1397 if (C->second == P) { 1398 DEBUG(dbgs() 1399 << "BBV: rejected to prevent non-trivial cycle formation: " 1400 << *C->first.first << " <-> " << *C->first.second << "\n"); 1401 return true; 1402 } 1403 1404 if (CurrentPairs.count(C->second) && !Visited.count(C->second)) 1405 Q.push_back(C->second); 1406 } 1407 } while (!Q.empty()); 1408 1409 return false; 1410 } 1411 1412 // This function builds the initial tree of connected pairs with the 1413 // pair J at the root. 1414 void BBVectorize::buildInitialTreeFor( 1415 std::multimap<Value *, Value *> &CandidatePairs, 1416 std::vector<Value *> &PairableInsts, 1417 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 1418 DenseSet<ValuePair> &PairableInstUsers, 1419 DenseMap<Value *, Value *> &ChosenPairs, 1420 DenseMap<ValuePair, size_t> &Tree, ValuePair J) { 1421 // Each of these pairs is viewed as the root node of a Tree. The Tree 1422 // is then walked (depth-first). As this happens, we keep track of 1423 // the pairs that compose the Tree and the maximum depth of the Tree. 1424 SmallVector<ValuePairWithDepth, 32> Q; 1425 // General depth-first post-order traversal: 1426 Q.push_back(ValuePairWithDepth(J, getDepthFactor(J.first))); 1427 do { 1428 ValuePairWithDepth QTop = Q.back(); 1429 1430 // Push each child onto the queue: 1431 bool MoreChildren = false; 1432 size_t MaxChildDepth = QTop.second; 1433 VPPIteratorPair qtRange = ConnectedPairs.equal_range(QTop.first); 1434 for (std::multimap<ValuePair, ValuePair>::iterator k = qtRange.first; 1435 k != qtRange.second; ++k) { 1436 // Make sure that this child pair is still a candidate: 1437 bool IsStillCand = false; 1438 VPIteratorPair checkRange = 1439 CandidatePairs.equal_range(k->second.first); 1440 for (std::multimap<Value *, Value *>::iterator m = checkRange.first; 1441 m != checkRange.second; ++m) { 1442 if (m->second == k->second.second) { 1443 IsStillCand = true; 1444 break; 1445 } 1446 } 1447 1448 if (IsStillCand) { 1449 DenseMap<ValuePair, size_t>::iterator C = Tree.find(k->second); 1450 if (C == Tree.end()) { 1451 size_t d = getDepthFactor(k->second.first); 1452 Q.push_back(ValuePairWithDepth(k->second, QTop.second+d)); 1453 MoreChildren = true; 1454 } else { 1455 MaxChildDepth = std::max(MaxChildDepth, C->second); 1456 } 1457 } 1458 } 1459 1460 if (!MoreChildren) { 1461 // Record the current pair as part of the Tree: 1462 Tree.insert(ValuePairWithDepth(QTop.first, MaxChildDepth)); 1463 Q.pop_back(); 1464 } 1465 } while (!Q.empty()); 1466 } 1467 1468 // Given some initial tree, prune it by removing conflicting pairs (pairs 1469 // that cannot be simultaneously chosen for vectorization). 1470 void BBVectorize::pruneTreeFor( 1471 std::multimap<Value *, Value *> &CandidatePairs, 1472 std::vector<Value *> &PairableInsts, 1473 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 1474 DenseSet<ValuePair> &PairableInstUsers, 1475 std::multimap<ValuePair, ValuePair> &PairableInstUserMap, 1476 DenseMap<Value *, Value *> &ChosenPairs, 1477 DenseMap<ValuePair, size_t> &Tree, 1478 DenseSet<ValuePair> &PrunedTree, ValuePair J, 1479 bool UseCycleCheck) { 1480 SmallVector<ValuePairWithDepth, 32> Q; 1481 // General depth-first post-order traversal: 1482 Q.push_back(ValuePairWithDepth(J, getDepthFactor(J.first))); 1483 do { 1484 ValuePairWithDepth QTop = Q.pop_back_val(); 1485 PrunedTree.insert(QTop.first); 1486 1487 // Visit each child, pruning as necessary... 1488 SmallVector<ValuePairWithDepth, 8> BestChildren; 1489 VPPIteratorPair QTopRange = ConnectedPairs.equal_range(QTop.first); 1490 for (std::multimap<ValuePair, ValuePair>::iterator K = QTopRange.first; 1491 K != QTopRange.second; ++K) { 1492 DenseMap<ValuePair, size_t>::iterator C = Tree.find(K->second); 1493 if (C == Tree.end()) continue; 1494 1495 // This child is in the Tree, now we need to make sure it is the 1496 // best of any conflicting children. There could be multiple 1497 // conflicting children, so first, determine if we're keeping 1498 // this child, then delete conflicting children as necessary. 1499 1500 // It is also necessary to guard against pairing-induced 1501 // dependencies. Consider instructions a .. x .. y .. b 1502 // such that (a,b) are to be fused and (x,y) are to be fused 1503 // but a is an input to x and b is an output from y. This 1504 // means that y cannot be moved after b but x must be moved 1505 // after b for (a,b) to be fused. In other words, after 1506 // fusing (a,b) we have y .. a/b .. x where y is an input 1507 // to a/b and x is an output to a/b: x and y can no longer 1508 // be legally fused. To prevent this condition, we must 1509 // make sure that a child pair added to the Tree is not 1510 // both an input and output of an already-selected pair. 1511 1512 // Pairing-induced dependencies can also form from more complicated 1513 // cycles. The pair vs. pair conflicts are easy to check, and so 1514 // that is done explicitly for "fast rejection", and because for 1515 // child vs. child conflicts, we may prefer to keep the current 1516 // pair in preference to the already-selected child. 1517 DenseSet<ValuePair> CurrentPairs; 1518 1519 bool CanAdd = true; 1520 for (SmallVector<ValuePairWithDepth, 8>::iterator C2 1521 = BestChildren.begin(), E2 = BestChildren.end(); 1522 C2 != E2; ++C2) { 1523 if (C2->first.first == C->first.first || 1524 C2->first.first == C->first.second || 1525 C2->first.second == C->first.first || 1526 C2->first.second == C->first.second || 1527 pairsConflict(C2->first, C->first, PairableInstUsers, 1528 UseCycleCheck ? &PairableInstUserMap : 0)) { 1529 if (C2->second >= C->second) { 1530 CanAdd = false; 1531 break; 1532 } 1533 1534 CurrentPairs.insert(C2->first); 1535 } 1536 } 1537 if (!CanAdd) continue; 1538 1539 // Even worse, this child could conflict with another node already 1540 // selected for the Tree. If that is the case, ignore this child. 1541 for (DenseSet<ValuePair>::iterator T = PrunedTree.begin(), 1542 E2 = PrunedTree.end(); T != E2; ++T) { 1543 if (T->first == C->first.first || 1544 T->first == C->first.second || 1545 T->second == C->first.first || 1546 T->second == C->first.second || 1547 pairsConflict(*T, C->first, PairableInstUsers, 1548 UseCycleCheck ? &PairableInstUserMap : 0)) { 1549 CanAdd = false; 1550 break; 1551 } 1552 1553 CurrentPairs.insert(*T); 1554 } 1555 if (!CanAdd) continue; 1556 1557 // And check the queue too... 1558 for (SmallVector<ValuePairWithDepth, 32>::iterator C2 = Q.begin(), 1559 E2 = Q.end(); C2 != E2; ++C2) { 1560 if (C2->first.first == C->first.first || 1561 C2->first.first == C->first.second || 1562 C2->first.second == C->first.first || 1563 C2->first.second == C->first.second || 1564 pairsConflict(C2->first, C->first, PairableInstUsers, 1565 UseCycleCheck ? &PairableInstUserMap : 0)) { 1566 CanAdd = false; 1567 break; 1568 } 1569 1570 CurrentPairs.insert(C2->first); 1571 } 1572 if (!CanAdd) continue; 1573 1574 // Last but not least, check for a conflict with any of the 1575 // already-chosen pairs. 1576 for (DenseMap<Value *, Value *>::iterator C2 = 1577 ChosenPairs.begin(), E2 = ChosenPairs.end(); 1578 C2 != E2; ++C2) { 1579 if (pairsConflict(*C2, C->first, PairableInstUsers, 1580 UseCycleCheck ? &PairableInstUserMap : 0)) { 1581 CanAdd = false; 1582 break; 1583 } 1584 1585 CurrentPairs.insert(*C2); 1586 } 1587 if (!CanAdd) continue; 1588 1589 // To check for non-trivial cycles formed by the addition of the 1590 // current pair we've formed a list of all relevant pairs, now use a 1591 // graph walk to check for a cycle. We start from the current pair and 1592 // walk the use tree to see if we again reach the current pair. If we 1593 // do, then the current pair is rejected. 1594 1595 // FIXME: It may be more efficient to use a topological-ordering 1596 // algorithm to improve the cycle check. This should be investigated. 1597 if (UseCycleCheck && 1598 pairWillFormCycle(C->first, PairableInstUserMap, CurrentPairs)) 1599 continue; 1600 1601 // This child can be added, but we may have chosen it in preference 1602 // to an already-selected child. Check for this here, and if a 1603 // conflict is found, then remove the previously-selected child 1604 // before adding this one in its place. 1605 for (SmallVector<ValuePairWithDepth, 8>::iterator C2 1606 = BestChildren.begin(); C2 != BestChildren.end();) { 1607 if (C2->first.first == C->first.first || 1608 C2->first.first == C->first.second || 1609 C2->first.second == C->first.first || 1610 C2->first.second == C->first.second || 1611 pairsConflict(C2->first, C->first, PairableInstUsers)) 1612 C2 = BestChildren.erase(C2); 1613 else 1614 ++C2; 1615 } 1616 1617 BestChildren.push_back(ValuePairWithDepth(C->first, C->second)); 1618 } 1619 1620 for (SmallVector<ValuePairWithDepth, 8>::iterator C 1621 = BestChildren.begin(), E2 = BestChildren.end(); 1622 C != E2; ++C) { 1623 size_t DepthF = getDepthFactor(C->first.first); 1624 Q.push_back(ValuePairWithDepth(C->first, QTop.second+DepthF)); 1625 } 1626 } while (!Q.empty()); 1627 } 1628 1629 // This function finds the best tree of mututally-compatible connected 1630 // pairs, given the choice of root pairs as an iterator range. 1631 void BBVectorize::findBestTreeFor( 1632 std::multimap<Value *, Value *> &CandidatePairs, 1633 DenseMap<ValuePair, int> &CandidatePairCostSavings, 1634 std::vector<Value *> &PairableInsts, 1635 DenseSet<ValuePair> &FixedOrderPairs, 1636 DenseMap<VPPair, unsigned> &PairConnectionTypes, 1637 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 1638 std::multimap<ValuePair, ValuePair> &ConnectedPairDeps, 1639 DenseSet<ValuePair> &PairableInstUsers, 1640 std::multimap<ValuePair, ValuePair> &PairableInstUserMap, 1641 DenseMap<Value *, Value *> &ChosenPairs, 1642 DenseSet<ValuePair> &BestTree, size_t &BestMaxDepth, 1643 int &BestEffSize, VPIteratorPair ChoiceRange, 1644 bool UseCycleCheck) { 1645 for (std::multimap<Value *, Value *>::iterator J = ChoiceRange.first; 1646 J != ChoiceRange.second; ++J) { 1647 1648 // Before going any further, make sure that this pair does not 1649 // conflict with any already-selected pairs (see comment below 1650 // near the Tree pruning for more details). 1651 DenseSet<ValuePair> ChosenPairSet; 1652 bool DoesConflict = false; 1653 for (DenseMap<Value *, Value *>::iterator C = ChosenPairs.begin(), 1654 E = ChosenPairs.end(); C != E; ++C) { 1655 if (pairsConflict(*C, *J, PairableInstUsers, 1656 UseCycleCheck ? &PairableInstUserMap : 0)) { 1657 DoesConflict = true; 1658 break; 1659 } 1660 1661 ChosenPairSet.insert(*C); 1662 } 1663 if (DoesConflict) continue; 1664 1665 if (UseCycleCheck && 1666 pairWillFormCycle(*J, PairableInstUserMap, ChosenPairSet)) 1667 continue; 1668 1669 DenseMap<ValuePair, size_t> Tree; 1670 buildInitialTreeFor(CandidatePairs, PairableInsts, ConnectedPairs, 1671 PairableInstUsers, ChosenPairs, Tree, *J); 1672 1673 // Because we'll keep the child with the largest depth, the largest 1674 // depth is still the same in the unpruned Tree. 1675 size_t MaxDepth = Tree.lookup(*J); 1676 1677 DEBUG(if (DebugPairSelection) dbgs() << "BBV: found Tree for pair {" 1678 << *J->first << " <-> " << *J->second << "} of depth " << 1679 MaxDepth << " and size " << Tree.size() << "\n"); 1680 1681 // At this point the Tree has been constructed, but, may contain 1682 // contradictory children (meaning that different children of 1683 // some tree node may be attempting to fuse the same instruction). 1684 // So now we walk the tree again, in the case of a conflict, 1685 // keep only the child with the largest depth. To break a tie, 1686 // favor the first child. 1687 1688 DenseSet<ValuePair> PrunedTree; 1689 pruneTreeFor(CandidatePairs, PairableInsts, ConnectedPairs, 1690 PairableInstUsers, PairableInstUserMap, ChosenPairs, Tree, 1691 PrunedTree, *J, UseCycleCheck); 1692 1693 int EffSize = 0; 1694 if (VTTI) { 1695 DenseSet<Value *> PrunedTreeInstrs; 1696 for (DenseSet<ValuePair>::iterator S = PrunedTree.begin(), 1697 E = PrunedTree.end(); S != E; ++S) { 1698 PrunedTreeInstrs.insert(S->first); 1699 PrunedTreeInstrs.insert(S->second); 1700 } 1701 1702 // The set of pairs that have already contributed to the total cost. 1703 DenseSet<ValuePair> IncomingPairs; 1704 1705 // If the cost model were perfect, this might not be necessary; but we 1706 // need to make sure that we don't get stuck vectorizing our own 1707 // shuffle chains. 1708 bool HasNontrivialInsts = false; 1709 1710 // The node weights represent the cost savings associated with 1711 // fusing the pair of instructions. 1712 for (DenseSet<ValuePair>::iterator S = PrunedTree.begin(), 1713 E = PrunedTree.end(); S != E; ++S) { 1714 if (!isa<ShuffleVectorInst>(S->first) && 1715 !isa<InsertElementInst>(S->first) && 1716 !isa<ExtractElementInst>(S->first)) 1717 HasNontrivialInsts = true; 1718 1719 bool FlipOrder = false; 1720 1721 if (getDepthFactor(S->first)) { 1722 int ESContrib = CandidatePairCostSavings.find(*S)->second; 1723 DEBUG(if (DebugPairSelection) dbgs() << "\tweight {" 1724 << *S->first << " <-> " << *S->second << "} = " << 1725 ESContrib << "\n"); 1726 EffSize += ESContrib; 1727 } 1728 1729 // The edge weights contribute in a negative sense: they represent 1730 // the cost of shuffles. 1731 VPPIteratorPair IP = ConnectedPairDeps.equal_range(*S); 1732 if (IP.first != ConnectedPairDeps.end()) { 1733 unsigned NumDepsDirect = 0, NumDepsSwap = 0; 1734 for (std::multimap<ValuePair, ValuePair>::iterator Q = IP.first; 1735 Q != IP.second; ++Q) { 1736 if (!PrunedTree.count(Q->second)) 1737 continue; 1738 DenseMap<VPPair, unsigned>::iterator R = 1739 PairConnectionTypes.find(VPPair(Q->second, Q->first)); 1740 assert(R != PairConnectionTypes.end() && 1741 "Cannot find pair connection type"); 1742 if (R->second == PairConnectionDirect) 1743 ++NumDepsDirect; 1744 else if (R->second == PairConnectionSwap) 1745 ++NumDepsSwap; 1746 } 1747 1748 // If there are more swaps than direct connections, then 1749 // the pair order will be flipped during fusion. So the real 1750 // number of swaps is the minimum number. 1751 FlipOrder = !FixedOrderPairs.count(*S) && 1752 ((NumDepsSwap > NumDepsDirect) || 1753 FixedOrderPairs.count(ValuePair(S->second, S->first))); 1754 1755 for (std::multimap<ValuePair, ValuePair>::iterator Q = IP.first; 1756 Q != IP.second; ++Q) { 1757 if (!PrunedTree.count(Q->second)) 1758 continue; 1759 DenseMap<VPPair, unsigned>::iterator R = 1760 PairConnectionTypes.find(VPPair(Q->second, Q->first)); 1761 assert(R != PairConnectionTypes.end() && 1762 "Cannot find pair connection type"); 1763 Type *Ty1 = Q->second.first->getType(), 1764 *Ty2 = Q->second.second->getType(); 1765 Type *VTy = getVecTypeForPair(Ty1, Ty2); 1766 if ((R->second == PairConnectionDirect && FlipOrder) || 1767 (R->second == PairConnectionSwap && !FlipOrder) || 1768 R->second == PairConnectionSplat) { 1769 int ESContrib = (int) getInstrCost(Instruction::ShuffleVector, 1770 VTy, VTy); 1771 DEBUG(if (DebugPairSelection) dbgs() << "\tcost {" << 1772 *Q->second.first << " <-> " << *Q->second.second << 1773 "} -> {" << 1774 *S->first << " <-> " << *S->second << "} = " << 1775 ESContrib << "\n"); 1776 EffSize -= ESContrib; 1777 } 1778 } 1779 } 1780 1781 // Compute the cost of outgoing edges. We assume that edges outgoing 1782 // to shuffles, inserts or extracts can be merged, and so contribute 1783 // no additional cost. 1784 if (!S->first->getType()->isVoidTy()) { 1785 Type *Ty1 = S->first->getType(), 1786 *Ty2 = S->second->getType(); 1787 Type *VTy = getVecTypeForPair(Ty1, Ty2); 1788 1789 bool NeedsExtraction = false; 1790 for (Value::use_iterator I = S->first->use_begin(), 1791 IE = S->first->use_end(); I != IE; ++I) { 1792 if (ShuffleVectorInst *SI = dyn_cast<ShuffleVectorInst>(*I)) { 1793 // Shuffle can be folded if it has no other input 1794 if (isa<UndefValue>(SI->getOperand(1))) 1795 continue; 1796 } 1797 if (isa<ExtractElementInst>(*I)) 1798 continue; 1799 if (PrunedTreeInstrs.count(*I)) 1800 continue; 1801 NeedsExtraction = true; 1802 break; 1803 } 1804 1805 if (NeedsExtraction) { 1806 int ESContrib; 1807 if (Ty1->isVectorTy()) 1808 ESContrib = (int) getInstrCost(Instruction::ShuffleVector, 1809 Ty1, VTy); 1810 else 1811 ESContrib = (int) VTTI->getVectorInstrCost( 1812 Instruction::ExtractElement, VTy, 0); 1813 1814 DEBUG(if (DebugPairSelection) dbgs() << "\tcost {" << 1815 *S->first << "} = " << ESContrib << "\n"); 1816 EffSize -= ESContrib; 1817 } 1818 1819 NeedsExtraction = false; 1820 for (Value::use_iterator I = S->second->use_begin(), 1821 IE = S->second->use_end(); I != IE; ++I) { 1822 if (ShuffleVectorInst *SI = dyn_cast<ShuffleVectorInst>(*I)) { 1823 // Shuffle can be folded if it has no other input 1824 if (isa<UndefValue>(SI->getOperand(1))) 1825 continue; 1826 } 1827 if (isa<ExtractElementInst>(*I)) 1828 continue; 1829 if (PrunedTreeInstrs.count(*I)) 1830 continue; 1831 NeedsExtraction = true; 1832 break; 1833 } 1834 1835 if (NeedsExtraction) { 1836 int ESContrib; 1837 if (Ty2->isVectorTy()) 1838 ESContrib = (int) getInstrCost(Instruction::ShuffleVector, 1839 Ty2, VTy); 1840 else 1841 ESContrib = (int) VTTI->getVectorInstrCost( 1842 Instruction::ExtractElement, VTy, 1); 1843 DEBUG(if (DebugPairSelection) dbgs() << "\tcost {" << 1844 *S->second << "} = " << ESContrib << "\n"); 1845 EffSize -= ESContrib; 1846 } 1847 } 1848 1849 // Compute the cost of incoming edges. 1850 if (!isa<LoadInst>(S->first) && !isa<StoreInst>(S->first)) { 1851 Instruction *S1 = cast<Instruction>(S->first), 1852 *S2 = cast<Instruction>(S->second); 1853 for (unsigned o = 0; o < S1->getNumOperands(); ++o) { 1854 Value *O1 = S1->getOperand(o), *O2 = S2->getOperand(o); 1855 1856 // Combining constants into vector constants (or small vector 1857 // constants into larger ones are assumed free). 1858 if (isa<Constant>(O1) && isa<Constant>(O2)) 1859 continue; 1860 1861 if (FlipOrder) 1862 std::swap(O1, O2); 1863 1864 ValuePair VP = ValuePair(O1, O2); 1865 ValuePair VPR = ValuePair(O2, O1); 1866 1867 // Internal edges are not handled here. 1868 if (PrunedTree.count(VP) || PrunedTree.count(VPR)) 1869 continue; 1870 1871 Type *Ty1 = O1->getType(), 1872 *Ty2 = O2->getType(); 1873 Type *VTy = getVecTypeForPair(Ty1, Ty2); 1874 1875 // Combining vector operations of the same type is also assumed 1876 // folded with other operations. 1877 if (Ty1 == Ty2) { 1878 // If both are insert elements, then both can be widened. 1879 InsertElementInst *IEO1 = dyn_cast<InsertElementInst>(O1), 1880 *IEO2 = dyn_cast<InsertElementInst>(O2); 1881 if (IEO1 && IEO2 && isPureIEChain(IEO1) && isPureIEChain(IEO2)) 1882 continue; 1883 // If both are extract elements, and both have the same input 1884 // type, then they can be replaced with a shuffle 1885 ExtractElementInst *EIO1 = dyn_cast<ExtractElementInst>(O1), 1886 *EIO2 = dyn_cast<ExtractElementInst>(O2); 1887 if (EIO1 && EIO2 && 1888 EIO1->getOperand(0)->getType() == 1889 EIO2->getOperand(0)->getType()) 1890 continue; 1891 // If both are a shuffle with equal operand types and only two 1892 // unqiue operands, then they can be replaced with a single 1893 // shuffle 1894 ShuffleVectorInst *SIO1 = dyn_cast<ShuffleVectorInst>(O1), 1895 *SIO2 = dyn_cast<ShuffleVectorInst>(O2); 1896 if (SIO1 && SIO2 && 1897 SIO1->getOperand(0)->getType() == 1898 SIO2->getOperand(0)->getType()) { 1899 SmallSet<Value *, 4> SIOps; 1900 SIOps.insert(SIO1->getOperand(0)); 1901 SIOps.insert(SIO1->getOperand(1)); 1902 SIOps.insert(SIO2->getOperand(0)); 1903 SIOps.insert(SIO2->getOperand(1)); 1904 if (SIOps.size() <= 2) 1905 continue; 1906 } 1907 } 1908 1909 int ESContrib; 1910 // This pair has already been formed. 1911 if (IncomingPairs.count(VP)) { 1912 continue; 1913 } else if (IncomingPairs.count(VPR)) { 1914 ESContrib = (int) getInstrCost(Instruction::ShuffleVector, 1915 VTy, VTy); 1916 } else if (!Ty1->isVectorTy() && !Ty2->isVectorTy()) { 1917 ESContrib = (int) VTTI->getVectorInstrCost( 1918 Instruction::InsertElement, VTy, 0); 1919 ESContrib += (int) VTTI->getVectorInstrCost( 1920 Instruction::InsertElement, VTy, 1); 1921 } else if (!Ty1->isVectorTy()) { 1922 // O1 needs to be inserted into a vector of size O2, and then 1923 // both need to be shuffled together. 1924 ESContrib = (int) VTTI->getVectorInstrCost( 1925 Instruction::InsertElement, Ty2, 0); 1926 ESContrib += (int) getInstrCost(Instruction::ShuffleVector, 1927 VTy, Ty2); 1928 } else if (!Ty2->isVectorTy()) { 1929 // O2 needs to be inserted into a vector of size O1, and then 1930 // both need to be shuffled together. 1931 ESContrib = (int) VTTI->getVectorInstrCost( 1932 Instruction::InsertElement, Ty1, 0); 1933 ESContrib += (int) getInstrCost(Instruction::ShuffleVector, 1934 VTy, Ty1); 1935 } else { 1936 Type *TyBig = Ty1, *TySmall = Ty2; 1937 if (Ty2->getVectorNumElements() > Ty1->getVectorNumElements()) 1938 std::swap(TyBig, TySmall); 1939 1940 ESContrib = (int) getInstrCost(Instruction::ShuffleVector, 1941 VTy, TyBig); 1942 if (TyBig != TySmall) 1943 ESContrib += (int) getInstrCost(Instruction::ShuffleVector, 1944 TyBig, TySmall); 1945 } 1946 1947 DEBUG(if (DebugPairSelection) dbgs() << "\tcost {" 1948 << *O1 << " <-> " << *O2 << "} = " << 1949 ESContrib << "\n"); 1950 EffSize -= ESContrib; 1951 IncomingPairs.insert(VP); 1952 } 1953 } 1954 } 1955 1956 if (!HasNontrivialInsts) { 1957 DEBUG(if (DebugPairSelection) dbgs() << 1958 "\tNo non-trivial instructions in tree;" 1959 " override to zero effective size\n"); 1960 EffSize = 0; 1961 } 1962 } else { 1963 for (DenseSet<ValuePair>::iterator S = PrunedTree.begin(), 1964 E = PrunedTree.end(); S != E; ++S) 1965 EffSize += (int) getDepthFactor(S->first); 1966 } 1967 1968 DEBUG(if (DebugPairSelection) 1969 dbgs() << "BBV: found pruned Tree for pair {" 1970 << *J->first << " <-> " << *J->second << "} of depth " << 1971 MaxDepth << " and size " << PrunedTree.size() << 1972 " (effective size: " << EffSize << ")\n"); 1973 if (((VTTI && !UseChainDepthWithTI) || 1974 MaxDepth >= Config.ReqChainDepth) && 1975 EffSize > 0 && EffSize > BestEffSize) { 1976 BestMaxDepth = MaxDepth; 1977 BestEffSize = EffSize; 1978 BestTree = PrunedTree; 1979 } 1980 } 1981 } 1982 1983 // Given the list of candidate pairs, this function selects those 1984 // that will be fused into vector instructions. 1985 void BBVectorize::choosePairs( 1986 std::multimap<Value *, Value *> &CandidatePairs, 1987 DenseMap<ValuePair, int> &CandidatePairCostSavings, 1988 std::vector<Value *> &PairableInsts, 1989 DenseSet<ValuePair> &FixedOrderPairs, 1990 DenseMap<VPPair, unsigned> &PairConnectionTypes, 1991 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 1992 std::multimap<ValuePair, ValuePair> &ConnectedPairDeps, 1993 DenseSet<ValuePair> &PairableInstUsers, 1994 DenseMap<Value *, Value *>& ChosenPairs) { 1995 bool UseCycleCheck = 1996 CandidatePairs.size() <= Config.MaxCandPairsForCycleCheck; 1997 std::multimap<ValuePair, ValuePair> PairableInstUserMap; 1998 for (std::vector<Value *>::iterator I = PairableInsts.begin(), 1999 E = PairableInsts.end(); I != E; ++I) { 2000 // The number of possible pairings for this variable: 2001 size_t NumChoices = CandidatePairs.count(*I); 2002 if (!NumChoices) continue; 2003 2004 VPIteratorPair ChoiceRange = CandidatePairs.equal_range(*I); 2005 2006 // The best pair to choose and its tree: 2007 size_t BestMaxDepth = 0; 2008 int BestEffSize = 0; 2009 DenseSet<ValuePair> BestTree; 2010 findBestTreeFor(CandidatePairs, CandidatePairCostSavings, 2011 PairableInsts, FixedOrderPairs, PairConnectionTypes, 2012 ConnectedPairs, ConnectedPairDeps, 2013 PairableInstUsers, PairableInstUserMap, ChosenPairs, 2014 BestTree, BestMaxDepth, BestEffSize, ChoiceRange, 2015 UseCycleCheck); 2016 2017 // A tree has been chosen (or not) at this point. If no tree was 2018 // chosen, then this instruction, I, cannot be paired (and is no longer 2019 // considered). 2020 2021 DEBUG(if (BestTree.size() > 0) 2022 dbgs() << "BBV: selected pairs in the best tree for: " 2023 << *cast<Instruction>(*I) << "\n"); 2024 2025 for (DenseSet<ValuePair>::iterator S = BestTree.begin(), 2026 SE2 = BestTree.end(); S != SE2; ++S) { 2027 // Insert the members of this tree into the list of chosen pairs. 2028 ChosenPairs.insert(ValuePair(S->first, S->second)); 2029 DEBUG(dbgs() << "BBV: selected pair: " << *S->first << " <-> " << 2030 *S->second << "\n"); 2031 2032 // Remove all candidate pairs that have values in the chosen tree. 2033 for (std::multimap<Value *, Value *>::iterator K = 2034 CandidatePairs.begin(); K != CandidatePairs.end();) { 2035 if (K->first == S->first || K->second == S->first || 2036 K->second == S->second || K->first == S->second) { 2037 // Don't remove the actual pair chosen so that it can be used 2038 // in subsequent tree selections. 2039 if (!(K->first == S->first && K->second == S->second)) 2040 CandidatePairs.erase(K++); 2041 else 2042 ++K; 2043 } else { 2044 ++K; 2045 } 2046 } 2047 } 2048 } 2049 2050 DEBUG(dbgs() << "BBV: selected " << ChosenPairs.size() << " pairs.\n"); 2051 } 2052 2053 std::string getReplacementName(Instruction *I, bool IsInput, unsigned o, 2054 unsigned n = 0) { 2055 if (!I->hasName()) 2056 return ""; 2057 2058 return (I->getName() + (IsInput ? ".v.i" : ".v.r") + utostr(o) + 2059 (n > 0 ? "." + utostr(n) : "")).str(); 2060 } 2061 2062 // Returns the value that is to be used as the pointer input to the vector 2063 // instruction that fuses I with J. 2064 Value *BBVectorize::getReplacementPointerInput(LLVMContext& Context, 2065 Instruction *I, Instruction *J, unsigned o) { 2066 Value *IPtr, *JPtr; 2067 unsigned IAlignment, JAlignment, IAddressSpace, JAddressSpace; 2068 int64_t OffsetInElmts; 2069 2070 // Note: the analysis might fail here, that is why the pair order has 2071 // been precomputed (OffsetInElmts must be unused here). 2072 (void) getPairPtrInfo(I, J, IPtr, JPtr, IAlignment, JAlignment, 2073 IAddressSpace, JAddressSpace, 2074 OffsetInElmts, false); 2075 2076 // The pointer value is taken to be the one with the lowest offset. 2077 Value *VPtr = IPtr; 2078 2079 Type *ArgTypeI = cast<PointerType>(IPtr->getType())->getElementType(); 2080 Type *ArgTypeJ = cast<PointerType>(JPtr->getType())->getElementType(); 2081 Type *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ); 2082 Type *VArgPtrType = PointerType::get(VArgType, 2083 cast<PointerType>(IPtr->getType())->getAddressSpace()); 2084 return new BitCastInst(VPtr, VArgPtrType, getReplacementName(I, true, o), 2085 /* insert before */ I); 2086 } 2087 2088 void BBVectorize::fillNewShuffleMask(LLVMContext& Context, Instruction *J, 2089 unsigned MaskOffset, unsigned NumInElem, 2090 unsigned NumInElem1, unsigned IdxOffset, 2091 std::vector<Constant*> &Mask) { 2092 unsigned NumElem1 = cast<VectorType>(J->getType())->getNumElements(); 2093 for (unsigned v = 0; v < NumElem1; ++v) { 2094 int m = cast<ShuffleVectorInst>(J)->getMaskValue(v); 2095 if (m < 0) { 2096 Mask[v+MaskOffset] = UndefValue::get(Type::getInt32Ty(Context)); 2097 } else { 2098 unsigned mm = m + (int) IdxOffset; 2099 if (m >= (int) NumInElem1) 2100 mm += (int) NumInElem; 2101 2102 Mask[v+MaskOffset] = 2103 ConstantInt::get(Type::getInt32Ty(Context), mm); 2104 } 2105 } 2106 } 2107 2108 // Returns the value that is to be used as the vector-shuffle mask to the 2109 // vector instruction that fuses I with J. 2110 Value *BBVectorize::getReplacementShuffleMask(LLVMContext& Context, 2111 Instruction *I, Instruction *J) { 2112 // This is the shuffle mask. We need to append the second 2113 // mask to the first, and the numbers need to be adjusted. 2114 2115 Type *ArgTypeI = I->getType(); 2116 Type *ArgTypeJ = J->getType(); 2117 Type *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ); 2118 2119 unsigned NumElemI = cast<VectorType>(ArgTypeI)->getNumElements(); 2120 2121 // Get the total number of elements in the fused vector type. 2122 // By definition, this must equal the number of elements in 2123 // the final mask. 2124 unsigned NumElem = cast<VectorType>(VArgType)->getNumElements(); 2125 std::vector<Constant*> Mask(NumElem); 2126 2127 Type *OpTypeI = I->getOperand(0)->getType(); 2128 unsigned NumInElemI = cast<VectorType>(OpTypeI)->getNumElements(); 2129 Type *OpTypeJ = J->getOperand(0)->getType(); 2130 unsigned NumInElemJ = cast<VectorType>(OpTypeJ)->getNumElements(); 2131 2132 // The fused vector will be: 2133 // ----------------------------------------------------- 2134 // | NumInElemI | NumInElemJ | NumInElemI | NumInElemJ | 2135 // ----------------------------------------------------- 2136 // from which we'll extract NumElem total elements (where the first NumElemI 2137 // of them come from the mask in I and the remainder come from the mask 2138 // in J. 2139 2140 // For the mask from the first pair... 2141 fillNewShuffleMask(Context, I, 0, NumInElemJ, NumInElemI, 2142 0, Mask); 2143 2144 // For the mask from the second pair... 2145 fillNewShuffleMask(Context, J, NumElemI, NumInElemI, NumInElemJ, 2146 NumInElemI, Mask); 2147 2148 return ConstantVector::get(Mask); 2149 } 2150 2151 bool BBVectorize::expandIEChain(LLVMContext& Context, Instruction *I, 2152 Instruction *J, unsigned o, Value *&LOp, 2153 unsigned numElemL, 2154 Type *ArgTypeL, Type *ArgTypeH, 2155 bool IBeforeJ, unsigned IdxOff) { 2156 bool ExpandedIEChain = false; 2157 if (InsertElementInst *LIE = dyn_cast<InsertElementInst>(LOp)) { 2158 // If we have a pure insertelement chain, then this can be rewritten 2159 // into a chain that directly builds the larger type. 2160 if (isPureIEChain(LIE)) { 2161 SmallVector<Value *, 8> VectElemts(numElemL, 2162 UndefValue::get(ArgTypeL->getScalarType())); 2163 InsertElementInst *LIENext = LIE; 2164 do { 2165 unsigned Idx = 2166 cast<ConstantInt>(LIENext->getOperand(2))->getSExtValue(); 2167 VectElemts[Idx] = LIENext->getOperand(1); 2168 } while ((LIENext = 2169 dyn_cast<InsertElementInst>(LIENext->getOperand(0)))); 2170 2171 LIENext = 0; 2172 Value *LIEPrev = UndefValue::get(ArgTypeH); 2173 for (unsigned i = 0; i < numElemL; ++i) { 2174 if (isa<UndefValue>(VectElemts[i])) continue; 2175 LIENext = InsertElementInst::Create(LIEPrev, VectElemts[i], 2176 ConstantInt::get(Type::getInt32Ty(Context), 2177 i + IdxOff), 2178 getReplacementName(IBeforeJ ? I : J, 2179 true, o, i+1)); 2180 LIENext->insertBefore(IBeforeJ ? J : I); 2181 LIEPrev = LIENext; 2182 } 2183 2184 LOp = LIENext ? (Value*) LIENext : UndefValue::get(ArgTypeH); 2185 ExpandedIEChain = true; 2186 } 2187 } 2188 2189 return ExpandedIEChain; 2190 } 2191 2192 // Returns the value to be used as the specified operand of the vector 2193 // instruction that fuses I with J. 2194 Value *BBVectorize::getReplacementInput(LLVMContext& Context, Instruction *I, 2195 Instruction *J, unsigned o, bool IBeforeJ) { 2196 Value *CV0 = ConstantInt::get(Type::getInt32Ty(Context), 0); 2197 Value *CV1 = ConstantInt::get(Type::getInt32Ty(Context), 1); 2198 2199 // Compute the fused vector type for this operand 2200 Type *ArgTypeI = I->getOperand(o)->getType(); 2201 Type *ArgTypeJ = J->getOperand(o)->getType(); 2202 VectorType *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ); 2203 2204 Instruction *L = I, *H = J; 2205 Type *ArgTypeL = ArgTypeI, *ArgTypeH = ArgTypeJ; 2206 2207 unsigned numElemL; 2208 if (ArgTypeL->isVectorTy()) 2209 numElemL = cast<VectorType>(ArgTypeL)->getNumElements(); 2210 else 2211 numElemL = 1; 2212 2213 unsigned numElemH; 2214 if (ArgTypeH->isVectorTy()) 2215 numElemH = cast<VectorType>(ArgTypeH)->getNumElements(); 2216 else 2217 numElemH = 1; 2218 2219 Value *LOp = L->getOperand(o); 2220 Value *HOp = H->getOperand(o); 2221 unsigned numElem = VArgType->getNumElements(); 2222 2223 // First, we check if we can reuse the "original" vector outputs (if these 2224 // exist). We might need a shuffle. 2225 ExtractElementInst *LEE = dyn_cast<ExtractElementInst>(LOp); 2226 ExtractElementInst *HEE = dyn_cast<ExtractElementInst>(HOp); 2227 ShuffleVectorInst *LSV = dyn_cast<ShuffleVectorInst>(LOp); 2228 ShuffleVectorInst *HSV = dyn_cast<ShuffleVectorInst>(HOp); 2229 2230 // FIXME: If we're fusing shuffle instructions, then we can't apply this 2231 // optimization. The input vectors to the shuffle might be a different 2232 // length from the shuffle outputs. Unfortunately, the replacement 2233 // shuffle mask has already been formed, and the mask entries are sensitive 2234 // to the sizes of the inputs. 2235 bool IsSizeChangeShuffle = 2236 isa<ShuffleVectorInst>(L) && 2237 (LOp->getType() != L->getType() || HOp->getType() != H->getType()); 2238 2239 if ((LEE || LSV) && (HEE || HSV) && !IsSizeChangeShuffle) { 2240 // We can have at most two unique vector inputs. 2241 bool CanUseInputs = true; 2242 Value *I1, *I2 = 0; 2243 if (LEE) { 2244 I1 = LEE->getOperand(0); 2245 } else { 2246 I1 = LSV->getOperand(0); 2247 I2 = LSV->getOperand(1); 2248 if (I2 == I1 || isa<UndefValue>(I2)) 2249 I2 = 0; 2250 } 2251 2252 if (HEE) { 2253 Value *I3 = HEE->getOperand(0); 2254 if (!I2 && I3 != I1) 2255 I2 = I3; 2256 else if (I3 != I1 && I3 != I2) 2257 CanUseInputs = false; 2258 } else { 2259 Value *I3 = HSV->getOperand(0); 2260 if (!I2 && I3 != I1) 2261 I2 = I3; 2262 else if (I3 != I1 && I3 != I2) 2263 CanUseInputs = false; 2264 2265 if (CanUseInputs) { 2266 Value *I4 = HSV->getOperand(1); 2267 if (!isa<UndefValue>(I4)) { 2268 if (!I2 && I4 != I1) 2269 I2 = I4; 2270 else if (I4 != I1 && I4 != I2) 2271 CanUseInputs = false; 2272 } 2273 } 2274 } 2275 2276 if (CanUseInputs) { 2277 unsigned LOpElem = 2278 cast<VectorType>(cast<Instruction>(LOp)->getOperand(0)->getType()) 2279 ->getNumElements(); 2280 unsigned HOpElem = 2281 cast<VectorType>(cast<Instruction>(HOp)->getOperand(0)->getType()) 2282 ->getNumElements(); 2283 2284 // We have one or two input vectors. We need to map each index of the 2285 // operands to the index of the original vector. 2286 SmallVector<std::pair<int, int>, 8> II(numElem); 2287 for (unsigned i = 0; i < numElemL; ++i) { 2288 int Idx, INum; 2289 if (LEE) { 2290 Idx = 2291 cast<ConstantInt>(LEE->getOperand(1))->getSExtValue(); 2292 INum = LEE->getOperand(0) == I1 ? 0 : 1; 2293 } else { 2294 Idx = LSV->getMaskValue(i); 2295 if (Idx < (int) LOpElem) { 2296 INum = LSV->getOperand(0) == I1 ? 0 : 1; 2297 } else { 2298 Idx -= LOpElem; 2299 INum = LSV->getOperand(1) == I1 ? 0 : 1; 2300 } 2301 } 2302 2303 II[i] = std::pair<int, int>(Idx, INum); 2304 } 2305 for (unsigned i = 0; i < numElemH; ++i) { 2306 int Idx, INum; 2307 if (HEE) { 2308 Idx = 2309 cast<ConstantInt>(HEE->getOperand(1))->getSExtValue(); 2310 INum = HEE->getOperand(0) == I1 ? 0 : 1; 2311 } else { 2312 Idx = HSV->getMaskValue(i); 2313 if (Idx < (int) HOpElem) { 2314 INum = HSV->getOperand(0) == I1 ? 0 : 1; 2315 } else { 2316 Idx -= HOpElem; 2317 INum = HSV->getOperand(1) == I1 ? 0 : 1; 2318 } 2319 } 2320 2321 II[i + numElemL] = std::pair<int, int>(Idx, INum); 2322 } 2323 2324 // We now have an array which tells us from which index of which 2325 // input vector each element of the operand comes. 2326 VectorType *I1T = cast<VectorType>(I1->getType()); 2327 unsigned I1Elem = I1T->getNumElements(); 2328 2329 if (!I2) { 2330 // In this case there is only one underlying vector input. Check for 2331 // the trivial case where we can use the input directly. 2332 if (I1Elem == numElem) { 2333 bool ElemInOrder = true; 2334 for (unsigned i = 0; i < numElem; ++i) { 2335 if (II[i].first != (int) i && II[i].first != -1) { 2336 ElemInOrder = false; 2337 break; 2338 } 2339 } 2340 2341 if (ElemInOrder) 2342 return I1; 2343 } 2344 2345 // A shuffle is needed. 2346 std::vector<Constant *> Mask(numElem); 2347 for (unsigned i = 0; i < numElem; ++i) { 2348 int Idx = II[i].first; 2349 if (Idx == -1) 2350 Mask[i] = UndefValue::get(Type::getInt32Ty(Context)); 2351 else 2352 Mask[i] = ConstantInt::get(Type::getInt32Ty(Context), Idx); 2353 } 2354 2355 Instruction *S = 2356 new ShuffleVectorInst(I1, UndefValue::get(I1T), 2357 ConstantVector::get(Mask), 2358 getReplacementName(IBeforeJ ? I : J, 2359 true, o)); 2360 S->insertBefore(IBeforeJ ? J : I); 2361 return S; 2362 } 2363 2364 VectorType *I2T = cast<VectorType>(I2->getType()); 2365 unsigned I2Elem = I2T->getNumElements(); 2366 2367 // This input comes from two distinct vectors. The first step is to 2368 // make sure that both vectors are the same length. If not, the 2369 // smaller one will need to grow before they can be shuffled together. 2370 if (I1Elem < I2Elem) { 2371 std::vector<Constant *> Mask(I2Elem); 2372 unsigned v = 0; 2373 for (; v < I1Elem; ++v) 2374 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v); 2375 for (; v < I2Elem; ++v) 2376 Mask[v] = UndefValue::get(Type::getInt32Ty(Context)); 2377 2378 Instruction *NewI1 = 2379 new ShuffleVectorInst(I1, UndefValue::get(I1T), 2380 ConstantVector::get(Mask), 2381 getReplacementName(IBeforeJ ? I : J, 2382 true, o, 1)); 2383 NewI1->insertBefore(IBeforeJ ? J : I); 2384 I1 = NewI1; 2385 I1T = I2T; 2386 I1Elem = I2Elem; 2387 } else if (I1Elem > I2Elem) { 2388 std::vector<Constant *> Mask(I1Elem); 2389 unsigned v = 0; 2390 for (; v < I2Elem; ++v) 2391 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v); 2392 for (; v < I1Elem; ++v) 2393 Mask[v] = UndefValue::get(Type::getInt32Ty(Context)); 2394 2395 Instruction *NewI2 = 2396 new ShuffleVectorInst(I2, UndefValue::get(I2T), 2397 ConstantVector::get(Mask), 2398 getReplacementName(IBeforeJ ? I : J, 2399 true, o, 1)); 2400 NewI2->insertBefore(IBeforeJ ? J : I); 2401 I2 = NewI2; 2402 I2T = I1T; 2403 I2Elem = I1Elem; 2404 } 2405 2406 // Now that both I1 and I2 are the same length we can shuffle them 2407 // together (and use the result). 2408 std::vector<Constant *> Mask(numElem); 2409 for (unsigned v = 0; v < numElem; ++v) { 2410 if (II[v].first == -1) { 2411 Mask[v] = UndefValue::get(Type::getInt32Ty(Context)); 2412 } else { 2413 int Idx = II[v].first + II[v].second * I1Elem; 2414 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), Idx); 2415 } 2416 } 2417 2418 Instruction *NewOp = 2419 new ShuffleVectorInst(I1, I2, ConstantVector::get(Mask), 2420 getReplacementName(IBeforeJ ? I : J, true, o)); 2421 NewOp->insertBefore(IBeforeJ ? J : I); 2422 return NewOp; 2423 } 2424 } 2425 2426 Type *ArgType = ArgTypeL; 2427 if (numElemL < numElemH) { 2428 if (numElemL == 1 && expandIEChain(Context, I, J, o, HOp, numElemH, 2429 ArgTypeL, VArgType, IBeforeJ, 1)) { 2430 // This is another short-circuit case: we're combining a scalar into 2431 // a vector that is formed by an IE chain. We've just expanded the IE 2432 // chain, now insert the scalar and we're done. 2433 2434 Instruction *S = InsertElementInst::Create(HOp, LOp, CV0, 2435 getReplacementName(IBeforeJ ? I : J, true, o)); 2436 S->insertBefore(IBeforeJ ? J : I); 2437 return S; 2438 } else if (!expandIEChain(Context, I, J, o, LOp, numElemL, ArgTypeL, 2439 ArgTypeH, IBeforeJ)) { 2440 // The two vector inputs to the shuffle must be the same length, 2441 // so extend the smaller vector to be the same length as the larger one. 2442 Instruction *NLOp; 2443 if (numElemL > 1) { 2444 2445 std::vector<Constant *> Mask(numElemH); 2446 unsigned v = 0; 2447 for (; v < numElemL; ++v) 2448 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v); 2449 for (; v < numElemH; ++v) 2450 Mask[v] = UndefValue::get(Type::getInt32Ty(Context)); 2451 2452 NLOp = new ShuffleVectorInst(LOp, UndefValue::get(ArgTypeL), 2453 ConstantVector::get(Mask), 2454 getReplacementName(IBeforeJ ? I : J, 2455 true, o, 1)); 2456 } else { 2457 NLOp = InsertElementInst::Create(UndefValue::get(ArgTypeH), LOp, CV0, 2458 getReplacementName(IBeforeJ ? I : J, 2459 true, o, 1)); 2460 } 2461 2462 NLOp->insertBefore(IBeforeJ ? J : I); 2463 LOp = NLOp; 2464 } 2465 2466 ArgType = ArgTypeH; 2467 } else if (numElemL > numElemH) { 2468 if (numElemH == 1 && expandIEChain(Context, I, J, o, LOp, numElemL, 2469 ArgTypeH, VArgType, IBeforeJ)) { 2470 Instruction *S = 2471 InsertElementInst::Create(LOp, HOp, 2472 ConstantInt::get(Type::getInt32Ty(Context), 2473 numElemL), 2474 getReplacementName(IBeforeJ ? I : J, 2475 true, o)); 2476 S->insertBefore(IBeforeJ ? J : I); 2477 return S; 2478 } else if (!expandIEChain(Context, I, J, o, HOp, numElemH, ArgTypeH, 2479 ArgTypeL, IBeforeJ)) { 2480 Instruction *NHOp; 2481 if (numElemH > 1) { 2482 std::vector<Constant *> Mask(numElemL); 2483 unsigned v = 0; 2484 for (; v < numElemH; ++v) 2485 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v); 2486 for (; v < numElemL; ++v) 2487 Mask[v] = UndefValue::get(Type::getInt32Ty(Context)); 2488 2489 NHOp = new ShuffleVectorInst(HOp, UndefValue::get(ArgTypeH), 2490 ConstantVector::get(Mask), 2491 getReplacementName(IBeforeJ ? I : J, 2492 true, o, 1)); 2493 } else { 2494 NHOp = InsertElementInst::Create(UndefValue::get(ArgTypeL), HOp, CV0, 2495 getReplacementName(IBeforeJ ? I : J, 2496 true, o, 1)); 2497 } 2498 2499 NHOp->insertBefore(IBeforeJ ? J : I); 2500 HOp = NHOp; 2501 } 2502 } 2503 2504 if (ArgType->isVectorTy()) { 2505 unsigned numElem = cast<VectorType>(VArgType)->getNumElements(); 2506 std::vector<Constant*> Mask(numElem); 2507 for (unsigned v = 0; v < numElem; ++v) { 2508 unsigned Idx = v; 2509 // If the low vector was expanded, we need to skip the extra 2510 // undefined entries. 2511 if (v >= numElemL && numElemH > numElemL) 2512 Idx += (numElemH - numElemL); 2513 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), Idx); 2514 } 2515 2516 Instruction *BV = new ShuffleVectorInst(LOp, HOp, 2517 ConstantVector::get(Mask), 2518 getReplacementName(IBeforeJ ? I : J, true, o)); 2519 BV->insertBefore(IBeforeJ ? J : I); 2520 return BV; 2521 } 2522 2523 Instruction *BV1 = InsertElementInst::Create( 2524 UndefValue::get(VArgType), LOp, CV0, 2525 getReplacementName(IBeforeJ ? I : J, 2526 true, o, 1)); 2527 BV1->insertBefore(IBeforeJ ? J : I); 2528 Instruction *BV2 = InsertElementInst::Create(BV1, HOp, CV1, 2529 getReplacementName(IBeforeJ ? I : J, 2530 true, o, 2)); 2531 BV2->insertBefore(IBeforeJ ? J : I); 2532 return BV2; 2533 } 2534 2535 // This function creates an array of values that will be used as the inputs 2536 // to the vector instruction that fuses I with J. 2537 void BBVectorize::getReplacementInputsForPair(LLVMContext& Context, 2538 Instruction *I, Instruction *J, 2539 SmallVector<Value *, 3> &ReplacedOperands, 2540 bool IBeforeJ) { 2541 unsigned NumOperands = I->getNumOperands(); 2542 2543 for (unsigned p = 0, o = NumOperands-1; p < NumOperands; ++p, --o) { 2544 // Iterate backward so that we look at the store pointer 2545 // first and know whether or not we need to flip the inputs. 2546 2547 if (isa<LoadInst>(I) || (o == 1 && isa<StoreInst>(I))) { 2548 // This is the pointer for a load/store instruction. 2549 ReplacedOperands[o] = getReplacementPointerInput(Context, I, J, o); 2550 continue; 2551 } else if (isa<CallInst>(I)) { 2552 Function *F = cast<CallInst>(I)->getCalledFunction(); 2553 unsigned IID = F->getIntrinsicID(); 2554 if (o == NumOperands-1) { 2555 BasicBlock &BB = *I->getParent(); 2556 2557 Module *M = BB.getParent()->getParent(); 2558 Type *ArgTypeI = I->getType(); 2559 Type *ArgTypeJ = J->getType(); 2560 Type *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ); 2561 2562 ReplacedOperands[o] = Intrinsic::getDeclaration(M, 2563 (Intrinsic::ID) IID, VArgType); 2564 continue; 2565 } else if (IID == Intrinsic::powi && o == 1) { 2566 // The second argument of powi is a single integer and we've already 2567 // checked that both arguments are equal. As a result, we just keep 2568 // I's second argument. 2569 ReplacedOperands[o] = I->getOperand(o); 2570 continue; 2571 } 2572 } else if (isa<ShuffleVectorInst>(I) && o == NumOperands-1) { 2573 ReplacedOperands[o] = getReplacementShuffleMask(Context, I, J); 2574 continue; 2575 } 2576 2577 ReplacedOperands[o] = getReplacementInput(Context, I, J, o, IBeforeJ); 2578 } 2579 } 2580 2581 // This function creates two values that represent the outputs of the 2582 // original I and J instructions. These are generally vector shuffles 2583 // or extracts. In many cases, these will end up being unused and, thus, 2584 // eliminated by later passes. 2585 void BBVectorize::replaceOutputsOfPair(LLVMContext& Context, Instruction *I, 2586 Instruction *J, Instruction *K, 2587 Instruction *&InsertionPt, 2588 Instruction *&K1, Instruction *&K2) { 2589 if (isa<StoreInst>(I)) { 2590 AA->replaceWithNewValue(I, K); 2591 AA->replaceWithNewValue(J, K); 2592 } else { 2593 Type *IType = I->getType(); 2594 Type *JType = J->getType(); 2595 2596 VectorType *VType = getVecTypeForPair(IType, JType); 2597 unsigned numElem = VType->getNumElements(); 2598 2599 unsigned numElemI, numElemJ; 2600 if (IType->isVectorTy()) 2601 numElemI = cast<VectorType>(IType)->getNumElements(); 2602 else 2603 numElemI = 1; 2604 2605 if (JType->isVectorTy()) 2606 numElemJ = cast<VectorType>(JType)->getNumElements(); 2607 else 2608 numElemJ = 1; 2609 2610 if (IType->isVectorTy()) { 2611 std::vector<Constant*> Mask1(numElemI), Mask2(numElemI); 2612 for (unsigned v = 0; v < numElemI; ++v) { 2613 Mask1[v] = ConstantInt::get(Type::getInt32Ty(Context), v); 2614 Mask2[v] = ConstantInt::get(Type::getInt32Ty(Context), numElemJ+v); 2615 } 2616 2617 K1 = new ShuffleVectorInst(K, UndefValue::get(VType), 2618 ConstantVector::get( Mask1), 2619 getReplacementName(K, false, 1)); 2620 } else { 2621 Value *CV0 = ConstantInt::get(Type::getInt32Ty(Context), 0); 2622 K1 = ExtractElementInst::Create(K, CV0, 2623 getReplacementName(K, false, 1)); 2624 } 2625 2626 if (JType->isVectorTy()) { 2627 std::vector<Constant*> Mask1(numElemJ), Mask2(numElemJ); 2628 for (unsigned v = 0; v < numElemJ; ++v) { 2629 Mask1[v] = ConstantInt::get(Type::getInt32Ty(Context), v); 2630 Mask2[v] = ConstantInt::get(Type::getInt32Ty(Context), numElemI+v); 2631 } 2632 2633 K2 = new ShuffleVectorInst(K, UndefValue::get(VType), 2634 ConstantVector::get( Mask2), 2635 getReplacementName(K, false, 2)); 2636 } else { 2637 Value *CV1 = ConstantInt::get(Type::getInt32Ty(Context), numElem-1); 2638 K2 = ExtractElementInst::Create(K, CV1, 2639 getReplacementName(K, false, 2)); 2640 } 2641 2642 K1->insertAfter(K); 2643 K2->insertAfter(K1); 2644 InsertionPt = K2; 2645 } 2646 } 2647 2648 // Move all uses of the function I (including pairing-induced uses) after J. 2649 bool BBVectorize::canMoveUsesOfIAfterJ(BasicBlock &BB, 2650 std::multimap<Value *, Value *> &LoadMoveSet, 2651 Instruction *I, Instruction *J) { 2652 // Skip to the first instruction past I. 2653 BasicBlock::iterator L = llvm::next(BasicBlock::iterator(I)); 2654 2655 DenseSet<Value *> Users; 2656 AliasSetTracker WriteSet(*AA); 2657 for (; cast<Instruction>(L) != J; ++L) 2658 (void) trackUsesOfI(Users, WriteSet, I, L, true, &LoadMoveSet); 2659 2660 assert(cast<Instruction>(L) == J && 2661 "Tracking has not proceeded far enough to check for dependencies"); 2662 // If J is now in the use set of I, then trackUsesOfI will return true 2663 // and we have a dependency cycle (and the fusing operation must abort). 2664 return !trackUsesOfI(Users, WriteSet, I, J, true, &LoadMoveSet); 2665 } 2666 2667 // Move all uses of the function I (including pairing-induced uses) after J. 2668 void BBVectorize::moveUsesOfIAfterJ(BasicBlock &BB, 2669 std::multimap<Value *, Value *> &LoadMoveSet, 2670 Instruction *&InsertionPt, 2671 Instruction *I, Instruction *J) { 2672 // Skip to the first instruction past I. 2673 BasicBlock::iterator L = llvm::next(BasicBlock::iterator(I)); 2674 2675 DenseSet<Value *> Users; 2676 AliasSetTracker WriteSet(*AA); 2677 for (; cast<Instruction>(L) != J;) { 2678 if (trackUsesOfI(Users, WriteSet, I, L, true, &LoadMoveSet)) { 2679 // Move this instruction 2680 Instruction *InstToMove = L; ++L; 2681 2682 DEBUG(dbgs() << "BBV: moving: " << *InstToMove << 2683 " to after " << *InsertionPt << "\n"); 2684 InstToMove->removeFromParent(); 2685 InstToMove->insertAfter(InsertionPt); 2686 InsertionPt = InstToMove; 2687 } else { 2688 ++L; 2689 } 2690 } 2691 } 2692 2693 // Collect all load instruction that are in the move set of a given first 2694 // pair member. These loads depend on the first instruction, I, and so need 2695 // to be moved after J (the second instruction) when the pair is fused. 2696 void BBVectorize::collectPairLoadMoveSet(BasicBlock &BB, 2697 DenseMap<Value *, Value *> &ChosenPairs, 2698 std::multimap<Value *, Value *> &LoadMoveSet, 2699 Instruction *I) { 2700 // Skip to the first instruction past I. 2701 BasicBlock::iterator L = llvm::next(BasicBlock::iterator(I)); 2702 2703 DenseSet<Value *> Users; 2704 AliasSetTracker WriteSet(*AA); 2705 2706 // Note: We cannot end the loop when we reach J because J could be moved 2707 // farther down the use chain by another instruction pairing. Also, J 2708 // could be before I if this is an inverted input. 2709 for (BasicBlock::iterator E = BB.end(); cast<Instruction>(L) != E; ++L) { 2710 if (trackUsesOfI(Users, WriteSet, I, L)) { 2711 if (L->mayReadFromMemory()) 2712 LoadMoveSet.insert(ValuePair(L, I)); 2713 } 2714 } 2715 } 2716 2717 // In cases where both load/stores and the computation of their pointers 2718 // are chosen for vectorization, we can end up in a situation where the 2719 // aliasing analysis starts returning different query results as the 2720 // process of fusing instruction pairs continues. Because the algorithm 2721 // relies on finding the same use trees here as were found earlier, we'll 2722 // need to precompute the necessary aliasing information here and then 2723 // manually update it during the fusion process. 2724 void BBVectorize::collectLoadMoveSet(BasicBlock &BB, 2725 std::vector<Value *> &PairableInsts, 2726 DenseMap<Value *, Value *> &ChosenPairs, 2727 std::multimap<Value *, Value *> &LoadMoveSet) { 2728 for (std::vector<Value *>::iterator PI = PairableInsts.begin(), 2729 PIE = PairableInsts.end(); PI != PIE; ++PI) { 2730 DenseMap<Value *, Value *>::iterator P = ChosenPairs.find(*PI); 2731 if (P == ChosenPairs.end()) continue; 2732 2733 Instruction *I = cast<Instruction>(P->first); 2734 collectPairLoadMoveSet(BB, ChosenPairs, LoadMoveSet, I); 2735 } 2736 } 2737 2738 // When the first instruction in each pair is cloned, it will inherit its 2739 // parent's metadata. This metadata must be combined with that of the other 2740 // instruction in a safe way. 2741 void BBVectorize::combineMetadata(Instruction *K, const Instruction *J) { 2742 SmallVector<std::pair<unsigned, MDNode*>, 4> Metadata; 2743 K->getAllMetadataOtherThanDebugLoc(Metadata); 2744 for (unsigned i = 0, n = Metadata.size(); i < n; ++i) { 2745 unsigned Kind = Metadata[i].first; 2746 MDNode *JMD = J->getMetadata(Kind); 2747 MDNode *KMD = Metadata[i].second; 2748 2749 switch (Kind) { 2750 default: 2751 K->setMetadata(Kind, 0); // Remove unknown metadata 2752 break; 2753 case LLVMContext::MD_tbaa: 2754 K->setMetadata(Kind, MDNode::getMostGenericTBAA(JMD, KMD)); 2755 break; 2756 case LLVMContext::MD_fpmath: 2757 K->setMetadata(Kind, MDNode::getMostGenericFPMath(JMD, KMD)); 2758 break; 2759 } 2760 } 2761 } 2762 2763 // This function fuses the chosen instruction pairs into vector instructions, 2764 // taking care preserve any needed scalar outputs and, then, it reorders the 2765 // remaining instructions as needed (users of the first member of the pair 2766 // need to be moved to after the location of the second member of the pair 2767 // because the vector instruction is inserted in the location of the pair's 2768 // second member). 2769 void BBVectorize::fuseChosenPairs(BasicBlock &BB, 2770 std::vector<Value *> &PairableInsts, 2771 DenseMap<Value *, Value *> &ChosenPairs, 2772 DenseSet<ValuePair> &FixedOrderPairs, 2773 DenseMap<VPPair, unsigned> &PairConnectionTypes, 2774 std::multimap<ValuePair, ValuePair> &ConnectedPairs, 2775 std::multimap<ValuePair, ValuePair> &ConnectedPairDeps) { 2776 LLVMContext& Context = BB.getContext(); 2777 2778 // During the vectorization process, the order of the pairs to be fused 2779 // could be flipped. So we'll add each pair, flipped, into the ChosenPairs 2780 // list. After a pair is fused, the flipped pair is removed from the list. 2781 DenseSet<ValuePair> FlippedPairs; 2782 for (DenseMap<Value *, Value *>::iterator P = ChosenPairs.begin(), 2783 E = ChosenPairs.end(); P != E; ++P) 2784 FlippedPairs.insert(ValuePair(P->second, P->first)); 2785 for (DenseSet<ValuePair>::iterator P = FlippedPairs.begin(), 2786 E = FlippedPairs.end(); P != E; ++P) 2787 ChosenPairs.insert(*P); 2788 2789 std::multimap<Value *, Value *> LoadMoveSet; 2790 collectLoadMoveSet(BB, PairableInsts, ChosenPairs, LoadMoveSet); 2791 2792 DEBUG(dbgs() << "BBV: initial: \n" << BB << "\n"); 2793 2794 for (BasicBlock::iterator PI = BB.getFirstInsertionPt(); PI != BB.end();) { 2795 DenseMap<Value *, Value *>::iterator P = ChosenPairs.find(PI); 2796 if (P == ChosenPairs.end()) { 2797 ++PI; 2798 continue; 2799 } 2800 2801 if (getDepthFactor(P->first) == 0) { 2802 // These instructions are not really fused, but are tracked as though 2803 // they are. Any case in which it would be interesting to fuse them 2804 // will be taken care of by InstCombine. 2805 --NumFusedOps; 2806 ++PI; 2807 continue; 2808 } 2809 2810 Instruction *I = cast<Instruction>(P->first), 2811 *J = cast<Instruction>(P->second); 2812 2813 DEBUG(dbgs() << "BBV: fusing: " << *I << 2814 " <-> " << *J << "\n"); 2815 2816 // Remove the pair and flipped pair from the list. 2817 DenseMap<Value *, Value *>::iterator FP = ChosenPairs.find(P->second); 2818 assert(FP != ChosenPairs.end() && "Flipped pair not found in list"); 2819 ChosenPairs.erase(FP); 2820 ChosenPairs.erase(P); 2821 2822 if (!canMoveUsesOfIAfterJ(BB, LoadMoveSet, I, J)) { 2823 DEBUG(dbgs() << "BBV: fusion of: " << *I << 2824 " <-> " << *J << 2825 " aborted because of non-trivial dependency cycle\n"); 2826 --NumFusedOps; 2827 ++PI; 2828 continue; 2829 } 2830 2831 // If the pair must have the other order, then flip it. 2832 bool FlipPairOrder = FixedOrderPairs.count(ValuePair(J, I)); 2833 if (!FlipPairOrder && !FixedOrderPairs.count(ValuePair(I, J))) { 2834 // This pair does not have a fixed order, and so we might want to 2835 // flip it if that will yield fewer shuffles. We count the number 2836 // of dependencies connected via swaps, and those directly connected, 2837 // and flip the order if the number of swaps is greater. 2838 bool OrigOrder = true; 2839 VPPIteratorPair IP = ConnectedPairDeps.equal_range(ValuePair(I, J)); 2840 if (IP.first == ConnectedPairDeps.end()) { 2841 IP = ConnectedPairDeps.equal_range(ValuePair(J, I)); 2842 OrigOrder = false; 2843 } 2844 2845 if (IP.first != ConnectedPairDeps.end()) { 2846 unsigned NumDepsDirect = 0, NumDepsSwap = 0; 2847 for (std::multimap<ValuePair, ValuePair>::iterator Q = IP.first; 2848 Q != IP.second; ++Q) { 2849 DenseMap<VPPair, unsigned>::iterator R = 2850 PairConnectionTypes.find(VPPair(Q->second, Q->first)); 2851 assert(R != PairConnectionTypes.end() && 2852 "Cannot find pair connection type"); 2853 if (R->second == PairConnectionDirect) 2854 ++NumDepsDirect; 2855 else if (R->second == PairConnectionSwap) 2856 ++NumDepsSwap; 2857 } 2858 2859 if (!OrigOrder) 2860 std::swap(NumDepsDirect, NumDepsSwap); 2861 2862 if (NumDepsSwap > NumDepsDirect) { 2863 FlipPairOrder = true; 2864 DEBUG(dbgs() << "BBV: reordering pair: " << *I << 2865 " <-> " << *J << "\n"); 2866 } 2867 } 2868 } 2869 2870 Instruction *L = I, *H = J; 2871 if (FlipPairOrder) 2872 std::swap(H, L); 2873 2874 // If the pair being fused uses the opposite order from that in the pair 2875 // connection map, then we need to flip the types. 2876 VPPIteratorPair IP = ConnectedPairs.equal_range(ValuePair(H, L)); 2877 for (std::multimap<ValuePair, ValuePair>::iterator Q = IP.first; 2878 Q != IP.second; ++Q) { 2879 DenseMap<VPPair, unsigned>::iterator R = PairConnectionTypes.find(*Q); 2880 assert(R != PairConnectionTypes.end() && 2881 "Cannot find pair connection type"); 2882 if (R->second == PairConnectionDirect) 2883 R->second = PairConnectionSwap; 2884 else if (R->second == PairConnectionSwap) 2885 R->second = PairConnectionDirect; 2886 } 2887 2888 bool LBeforeH = !FlipPairOrder; 2889 unsigned NumOperands = I->getNumOperands(); 2890 SmallVector<Value *, 3> ReplacedOperands(NumOperands); 2891 getReplacementInputsForPair(Context, L, H, ReplacedOperands, 2892 LBeforeH); 2893 2894 // Make a copy of the original operation, change its type to the vector 2895 // type and replace its operands with the vector operands. 2896 Instruction *K = L->clone(); 2897 if (L->hasName()) 2898 K->takeName(L); 2899 else if (H->hasName()) 2900 K->takeName(H); 2901 2902 if (!isa<StoreInst>(K)) 2903 K->mutateType(getVecTypeForPair(L->getType(), H->getType())); 2904 2905 combineMetadata(K, H); 2906 2907 for (unsigned o = 0; o < NumOperands; ++o) 2908 K->setOperand(o, ReplacedOperands[o]); 2909 2910 K->insertAfter(J); 2911 2912 // Instruction insertion point: 2913 Instruction *InsertionPt = K; 2914 Instruction *K1 = 0, *K2 = 0; 2915 replaceOutputsOfPair(Context, L, H, K, InsertionPt, K1, K2); 2916 2917 // The use tree of the first original instruction must be moved to after 2918 // the location of the second instruction. The entire use tree of the 2919 // first instruction is disjoint from the input tree of the second 2920 // (by definition), and so commutes with it. 2921 2922 moveUsesOfIAfterJ(BB, LoadMoveSet, InsertionPt, I, J); 2923 2924 if (!isa<StoreInst>(I)) { 2925 L->replaceAllUsesWith(K1); 2926 H->replaceAllUsesWith(K2); 2927 AA->replaceWithNewValue(L, K1); 2928 AA->replaceWithNewValue(H, K2); 2929 } 2930 2931 // Instructions that may read from memory may be in the load move set. 2932 // Once an instruction is fused, we no longer need its move set, and so 2933 // the values of the map never need to be updated. However, when a load 2934 // is fused, we need to merge the entries from both instructions in the 2935 // pair in case those instructions were in the move set of some other 2936 // yet-to-be-fused pair. The loads in question are the keys of the map. 2937 if (I->mayReadFromMemory()) { 2938 std::vector<ValuePair> NewSetMembers; 2939 VPIteratorPair IPairRange = LoadMoveSet.equal_range(I); 2940 VPIteratorPair JPairRange = LoadMoveSet.equal_range(J); 2941 for (std::multimap<Value *, Value *>::iterator N = IPairRange.first; 2942 N != IPairRange.second; ++N) 2943 NewSetMembers.push_back(ValuePair(K, N->second)); 2944 for (std::multimap<Value *, Value *>::iterator N = JPairRange.first; 2945 N != JPairRange.second; ++N) 2946 NewSetMembers.push_back(ValuePair(K, N->second)); 2947 for (std::vector<ValuePair>::iterator A = NewSetMembers.begin(), 2948 AE = NewSetMembers.end(); A != AE; ++A) 2949 LoadMoveSet.insert(*A); 2950 } 2951 2952 // Before removing I, set the iterator to the next instruction. 2953 PI = llvm::next(BasicBlock::iterator(I)); 2954 if (cast<Instruction>(PI) == J) 2955 ++PI; 2956 2957 SE->forgetValue(I); 2958 SE->forgetValue(J); 2959 I->eraseFromParent(); 2960 J->eraseFromParent(); 2961 2962 DEBUG(if (PrintAfterEveryPair) dbgs() << "BBV: block is now: \n" << 2963 BB << "\n"); 2964 } 2965 2966 DEBUG(dbgs() << "BBV: final: \n" << BB << "\n"); 2967 } 2968} 2969 2970char BBVectorize::ID = 0; 2971static const char bb_vectorize_name[] = "Basic-Block Vectorization"; 2972INITIALIZE_PASS_BEGIN(BBVectorize, BBV_NAME, bb_vectorize_name, false, false) 2973INITIALIZE_AG_DEPENDENCY(AliasAnalysis) 2974INITIALIZE_PASS_DEPENDENCY(DominatorTree) 2975INITIALIZE_PASS_DEPENDENCY(ScalarEvolution) 2976INITIALIZE_PASS_END(BBVectorize, BBV_NAME, bb_vectorize_name, false, false) 2977 2978BasicBlockPass *llvm::createBBVectorizePass(const VectorizeConfig &C) { 2979 return new BBVectorize(C); 2980} 2981 2982bool 2983llvm::vectorizeBasicBlock(Pass *P, BasicBlock &BB, const VectorizeConfig &C) { 2984 BBVectorize BBVectorizer(P, C); 2985 return BBVectorizer.vectorizeBB(BB); 2986} 2987 2988//===----------------------------------------------------------------------===// 2989VectorizeConfig::VectorizeConfig() { 2990 VectorBits = ::VectorBits; 2991 VectorizeBools = !::NoBools; 2992 VectorizeInts = !::NoInts; 2993 VectorizeFloats = !::NoFloats; 2994 VectorizePointers = !::NoPointers; 2995 VectorizeCasts = !::NoCasts; 2996 VectorizeMath = !::NoMath; 2997 VectorizeFMA = !::NoFMA; 2998 VectorizeSelect = !::NoSelect; 2999 VectorizeCmp = !::NoCmp; 3000 VectorizeGEP = !::NoGEP; 3001 VectorizeMemOps = !::NoMemOps; 3002 AlignedOnly = ::AlignedOnly; 3003 ReqChainDepth= ::ReqChainDepth; 3004 SearchLimit = ::SearchLimit; 3005 MaxCandPairsForCycleCheck = ::MaxCandPairsForCycleCheck; 3006 SplatBreaksChain = ::SplatBreaksChain; 3007 MaxInsts = ::MaxInsts; 3008 MaxIter = ::MaxIter; 3009 Pow2LenOnly = ::Pow2LenOnly; 3010 NoMemOpBoost = ::NoMemOpBoost; 3011 FastDep = ::FastDep; 3012} 3013