1 //===- BBVectorize.cpp - A Basic-Block Vectorizer -------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
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
15 //===----------------------------------------------------------------------===//
17 #define BBV_NAME "bb-vectorize"
18 #define DEBUG_TYPE BBV_NAME
19 #include "llvm/Transforms/Vectorize.h"
20 #include "llvm/ADT/DenseMap.h"
21 #include "llvm/ADT/DenseSet.h"
22 #include "llvm/ADT/STLExtras.h"
23 #include "llvm/ADT/SmallSet.h"
24 #include "llvm/ADT/SmallVector.h"
25 #include "llvm/ADT/Statistic.h"
26 #include "llvm/ADT/StringExtras.h"
27 #include "llvm/Analysis/AliasAnalysis.h"
28 #include "llvm/Analysis/AliasSetTracker.h"
29 #include "llvm/Analysis/Dominators.h"
30 #include "llvm/Analysis/ScalarEvolution.h"
31 #include "llvm/Analysis/ScalarEvolutionExpressions.h"
32 #include "llvm/Analysis/TargetTransformInfo.h"
33 #include "llvm/Analysis/ValueTracking.h"
34 #include "llvm/IR/Constants.h"
35 #include "llvm/IR/DataLayout.h"
36 #include "llvm/IR/DerivedTypes.h"
37 #include "llvm/IR/Function.h"
38 #include "llvm/IR/Instructions.h"
39 #include "llvm/IR/IntrinsicInst.h"
40 #include "llvm/IR/Intrinsics.h"
41 #include "llvm/IR/LLVMContext.h"
42 #include "llvm/IR/Metadata.h"
43 #include "llvm/IR/Type.h"
44 #include "llvm/Pass.h"
45 #include "llvm/Support/CommandLine.h"
46 #include "llvm/Support/Debug.h"
47 #include "llvm/Support/ValueHandle.h"
48 #include "llvm/Support/raw_ostream.h"
49 #include "llvm/Transforms/Utils/Local.h"
55 IgnoreTargetInfo("bb-vectorize-ignore-target-info", cl::init(false),
56 cl::Hidden, cl::desc("Ignore target information"));
58 static cl::opt<unsigned>
59 ReqChainDepth("bb-vectorize-req-chain-depth", cl::init(6), cl::Hidden,
60 cl::desc("The required chain depth for vectorization"));
63 UseChainDepthWithTI("bb-vectorize-use-chain-depth", cl::init(false),
64 cl::Hidden, cl::desc("Use the chain depth requirement with"
65 " target information"));
67 static cl::opt<unsigned>
68 SearchLimit("bb-vectorize-search-limit", cl::init(400), cl::Hidden,
69 cl::desc("The maximum search distance for instruction pairs"));
72 SplatBreaksChain("bb-vectorize-splat-breaks-chain", cl::init(false), cl::Hidden,
73 cl::desc("Replicating one element to a pair breaks the chain"));
75 static cl::opt<unsigned>
76 VectorBits("bb-vectorize-vector-bits", cl::init(128), cl::Hidden,
77 cl::desc("The size of the native vector registers"));
79 static cl::opt<unsigned>
80 MaxIter("bb-vectorize-max-iter", cl::init(0), cl::Hidden,
81 cl::desc("The maximum number of pairing iterations"));
84 Pow2LenOnly("bb-vectorize-pow2-len-only", cl::init(false), cl::Hidden,
85 cl::desc("Don't try to form non-2^n-length vectors"));
87 static cl::opt<unsigned>
88 MaxInsts("bb-vectorize-max-instr-per-group", cl::init(500), cl::Hidden,
89 cl::desc("The maximum number of pairable instructions per group"));
91 static cl::opt<unsigned>
92 MaxCandPairsForCycleCheck("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"));
97 NoBools("bb-vectorize-no-bools", cl::init(false), cl::Hidden,
98 cl::desc("Don't try to vectorize boolean (i1) values"));
101 NoInts("bb-vectorize-no-ints", cl::init(false), cl::Hidden,
102 cl::desc("Don't try to vectorize integer values"));
105 NoFloats("bb-vectorize-no-floats", cl::init(false), cl::Hidden,
106 cl::desc("Don't try to vectorize floating-point values"));
108 // FIXME: This should default to false once pointer vector support works.
110 NoPointers("bb-vectorize-no-pointers", cl::init(/*false*/ true), cl::Hidden,
111 cl::desc("Don't try to vectorize pointer values"));
114 NoCasts("bb-vectorize-no-casts", cl::init(false), cl::Hidden,
115 cl::desc("Don't try to vectorize casting (conversion) operations"));
118 NoMath("bb-vectorize-no-math", cl::init(false), cl::Hidden,
119 cl::desc("Don't try to vectorize floating-point math intrinsics"));
122 NoFMA("bb-vectorize-no-fma", cl::init(false), cl::Hidden,
123 cl::desc("Don't try to vectorize the fused-multiply-add intrinsic"));
126 NoSelect("bb-vectorize-no-select", cl::init(false), cl::Hidden,
127 cl::desc("Don't try to vectorize select instructions"));
130 NoCmp("bb-vectorize-no-cmp", cl::init(false), cl::Hidden,
131 cl::desc("Don't try to vectorize comparison instructions"));
134 NoGEP("bb-vectorize-no-gep", cl::init(false), cl::Hidden,
135 cl::desc("Don't try to vectorize getelementptr instructions"));
138 NoMemOps("bb-vectorize-no-mem-ops", cl::init(false), cl::Hidden,
139 cl::desc("Don't try to vectorize loads and stores"));
142 AlignedOnly("bb-vectorize-aligned-only", cl::init(false), cl::Hidden,
143 cl::desc("Only generate aligned loads and stores"));
146 NoMemOpBoost("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"));
151 FastDep("bb-vectorize-fast-dep", cl::init(false), cl::Hidden,
152 cl::desc("Use a fast instruction dependency analysis"));
156 DebugInstructionExamination("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"));
161 DebugCandidateSelection("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"));
166 DebugPairSelection("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"));
171 DebugCycleCheck("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"));
177 PrintAfterEveryPair("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"));
183 STATISTIC(NumFusedOps, "Number of operations fused by bb-vectorize");
186 struct BBVectorize : public BasicBlockPass {
187 static char ID; // Pass identification, replacement for typeid
189 const VectorizeConfig Config;
191 BBVectorize(const VectorizeConfig &C = VectorizeConfig())
192 : BasicBlockPass(ID), Config(C) {
193 initializeBBVectorizePass(*PassRegistry::getPassRegistry());
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 : &P->getAnalysis<TargetTransformInfo>();
205 typedef std::pair<Value *, Value *> ValuePair;
206 typedef std::pair<ValuePair, int> ValuePairWithCost;
207 typedef std::pair<ValuePair, size_t> ValuePairWithDepth;
208 typedef std::pair<ValuePair, ValuePair> VPPair; // A ValuePair pair
209 typedef std::pair<VPPair, unsigned> VPPairWithType;
210 typedef std::pair<std::multimap<Value *, Value *>::iterator,
211 std::multimap<Value *, Value *>::iterator> VPIteratorPair;
212 typedef std::pair<std::multimap<ValuePair, ValuePair>::iterator,
213 std::multimap<ValuePair, ValuePair>::iterator>
220 const TargetTransformInfo *TTI;
222 // FIXME: const correct?
224 bool vectorizePairs(BasicBlock &BB, bool NonPow2Len = false);
226 bool getCandidatePairs(BasicBlock &BB,
227 BasicBlock::iterator &Start,
228 std::multimap<Value *, Value *> &CandidatePairs,
229 DenseSet<ValuePair> &FixedOrderPairs,
230 DenseMap<ValuePair, int> &CandidatePairCostSavings,
231 std::vector<Value *> &PairableInsts, bool NonPow2Len);
233 // FIXME: The current implementation does not account for pairs that
234 // are connected in multiple ways. For example:
235 // C1 = A1 / A2; C2 = A2 / A1 (which may be both direct and a swap)
236 enum PairConnectionType {
237 PairConnectionDirect,
242 void computeConnectedPairs(std::multimap<Value *, Value *> &CandidatePairs,
243 std::vector<Value *> &PairableInsts,
244 std::multimap<ValuePair, ValuePair> &ConnectedPairs,
245 DenseMap<VPPair, unsigned> &PairConnectionTypes);
247 void buildDepMap(BasicBlock &BB,
248 std::multimap<Value *, Value *> &CandidatePairs,
249 std::vector<Value *> &PairableInsts,
250 DenseSet<ValuePair> &PairableInstUsers);
252 void choosePairs(std::multimap<Value *, Value *> &CandidatePairs,
253 DenseMap<ValuePair, int> &CandidatePairCostSavings,
254 std::vector<Value *> &PairableInsts,
255 DenseSet<ValuePair> &FixedOrderPairs,
256 DenseMap<VPPair, unsigned> &PairConnectionTypes,
257 std::multimap<ValuePair, ValuePair> &ConnectedPairs,
258 std::multimap<ValuePair, ValuePair> &ConnectedPairDeps,
259 DenseSet<ValuePair> &PairableInstUsers,
260 DenseMap<Value *, Value *>& ChosenPairs);
262 void fuseChosenPairs(BasicBlock &BB,
263 std::vector<Value *> &PairableInsts,
264 DenseMap<Value *, Value *>& ChosenPairs,
265 DenseSet<ValuePair> &FixedOrderPairs,
266 DenseMap<VPPair, unsigned> &PairConnectionTypes,
267 std::multimap<ValuePair, ValuePair> &ConnectedPairs,
268 std::multimap<ValuePair, ValuePair> &ConnectedPairDeps);
271 bool isInstVectorizable(Instruction *I, bool &IsSimpleLoadStore);
273 bool areInstsCompatible(Instruction *I, Instruction *J,
274 bool IsSimpleLoadStore, bool NonPow2Len,
275 int &CostSavings, int &FixedOrder);
277 bool trackUsesOfI(DenseSet<Value *> &Users,
278 AliasSetTracker &WriteSet, Instruction *I,
279 Instruction *J, bool UpdateUsers = true,
280 std::multimap<Value *, Value *> *LoadMoveSet = 0);
282 void computePairsConnectedTo(
283 std::multimap<Value *, Value *> &CandidatePairs,
284 std::vector<Value *> &PairableInsts,
285 std::multimap<ValuePair, ValuePair> &ConnectedPairs,
286 DenseMap<VPPair, unsigned> &PairConnectionTypes,
289 bool pairsConflict(ValuePair P, ValuePair Q,
290 DenseSet<ValuePair> &PairableInstUsers,
291 std::multimap<ValuePair, ValuePair> *PairableInstUserMap = 0);
293 bool pairWillFormCycle(ValuePair P,
294 std::multimap<ValuePair, ValuePair> &PairableInstUsers,
295 DenseSet<ValuePair> &CurrentPairs);
298 std::multimap<Value *, Value *> &CandidatePairs,
299 std::vector<Value *> &PairableInsts,
300 std::multimap<ValuePair, ValuePair> &ConnectedPairs,
301 DenseSet<ValuePair> &PairableInstUsers,
302 std::multimap<ValuePair, ValuePair> &PairableInstUserMap,
303 DenseMap<Value *, Value *> &ChosenPairs,
304 DenseMap<ValuePair, size_t> &Tree,
305 DenseSet<ValuePair> &PrunedTree, ValuePair J,
308 void buildInitialTreeFor(
309 std::multimap<Value *, Value *> &CandidatePairs,
310 std::vector<Value *> &PairableInsts,
311 std::multimap<ValuePair, ValuePair> &ConnectedPairs,
312 DenseSet<ValuePair> &PairableInstUsers,
313 DenseMap<Value *, Value *> &ChosenPairs,
314 DenseMap<ValuePair, size_t> &Tree, ValuePair J);
316 void findBestTreeFor(
317 std::multimap<Value *, Value *> &CandidatePairs,
318 DenseMap<ValuePair, int> &CandidatePairCostSavings,
319 std::vector<Value *> &PairableInsts,
320 DenseSet<ValuePair> &FixedOrderPairs,
321 DenseMap<VPPair, unsigned> &PairConnectionTypes,
322 std::multimap<ValuePair, ValuePair> &ConnectedPairs,
323 std::multimap<ValuePair, ValuePair> &ConnectedPairDeps,
324 DenseSet<ValuePair> &PairableInstUsers,
325 std::multimap<ValuePair, ValuePair> &PairableInstUserMap,
326 DenseMap<Value *, Value *> &ChosenPairs,
327 DenseSet<ValuePair> &BestTree, size_t &BestMaxDepth,
328 int &BestEffSize, VPIteratorPair ChoiceRange,
331 Value *getReplacementPointerInput(LLVMContext& Context, Instruction *I,
332 Instruction *J, unsigned o);
334 void fillNewShuffleMask(LLVMContext& Context, Instruction *J,
335 unsigned MaskOffset, unsigned NumInElem,
336 unsigned NumInElem1, unsigned IdxOffset,
337 std::vector<Constant*> &Mask);
339 Value *getReplacementShuffleMask(LLVMContext& Context, Instruction *I,
342 bool expandIEChain(LLVMContext& Context, Instruction *I, Instruction *J,
343 unsigned o, Value *&LOp, unsigned numElemL,
344 Type *ArgTypeL, Type *ArgTypeR, bool IBeforeJ,
345 unsigned IdxOff = 0);
347 Value *getReplacementInput(LLVMContext& Context, Instruction *I,
348 Instruction *J, unsigned o, bool IBeforeJ);
350 void getReplacementInputsForPair(LLVMContext& Context, Instruction *I,
351 Instruction *J, SmallVector<Value *, 3> &ReplacedOperands,
354 void replaceOutputsOfPair(LLVMContext& Context, Instruction *I,
355 Instruction *J, Instruction *K,
356 Instruction *&InsertionPt, Instruction *&K1,
359 void collectPairLoadMoveSet(BasicBlock &BB,
360 DenseMap<Value *, Value *> &ChosenPairs,
361 std::multimap<Value *, Value *> &LoadMoveSet,
364 void collectLoadMoveSet(BasicBlock &BB,
365 std::vector<Value *> &PairableInsts,
366 DenseMap<Value *, Value *> &ChosenPairs,
367 std::multimap<Value *, Value *> &LoadMoveSet);
369 bool canMoveUsesOfIAfterJ(BasicBlock &BB,
370 std::multimap<Value *, Value *> &LoadMoveSet,
371 Instruction *I, Instruction *J);
373 void moveUsesOfIAfterJ(BasicBlock &BB,
374 std::multimap<Value *, Value *> &LoadMoveSet,
375 Instruction *&InsertionPt,
376 Instruction *I, Instruction *J);
378 void combineMetadata(Instruction *K, const Instruction *J);
380 bool vectorizeBB(BasicBlock &BB) {
381 if (!DT->isReachableFromEntry(&BB)) {
382 DEBUG(dbgs() << "BBV: skipping unreachable " << BB.getName() <<
383 " in " << BB.getParent()->getName() << "\n");
387 DEBUG(if (TTI) dbgs() << "BBV: using target information\n");
389 bool changed = false;
390 // Iterate a sufficient number of times to merge types of size 1 bit,
391 // then 2 bits, then 4, etc. up to half of the target vector width of the
392 // target vector register.
395 (TTI || v <= Config.VectorBits) &&
396 (!Config.MaxIter || n <= Config.MaxIter);
398 DEBUG(dbgs() << "BBV: fusing loop #" << n <<
399 " for " << BB.getName() << " in " <<
400 BB.getParent()->getName() << "...\n");
401 if (vectorizePairs(BB))
407 if (changed && !Pow2LenOnly) {
409 for (; !Config.MaxIter || n <= Config.MaxIter; ++n) {
410 DEBUG(dbgs() << "BBV: fusing for non-2^n-length vectors loop #: " <<
411 n << " for " << BB.getName() << " in " <<
412 BB.getParent()->getName() << "...\n");
413 if (!vectorizePairs(BB, true)) break;
417 DEBUG(dbgs() << "BBV: done!\n");
421 virtual bool runOnBasicBlock(BasicBlock &BB) {
422 AA = &getAnalysis<AliasAnalysis>();
423 DT = &getAnalysis<DominatorTree>();
424 SE = &getAnalysis<ScalarEvolution>();
425 TD = getAnalysisIfAvailable<DataLayout>();
426 TTI = IgnoreTargetInfo ? 0 : &getAnalysis<TargetTransformInfo>();
428 return vectorizeBB(BB);
431 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
432 BasicBlockPass::getAnalysisUsage(AU);
433 AU.addRequired<AliasAnalysis>();
434 AU.addRequired<DominatorTree>();
435 AU.addRequired<ScalarEvolution>();
436 AU.addRequired<TargetTransformInfo>();
437 AU.addPreserved<AliasAnalysis>();
438 AU.addPreserved<DominatorTree>();
439 AU.addPreserved<ScalarEvolution>();
440 AU.setPreservesCFG();
443 static inline VectorType *getVecTypeForPair(Type *ElemTy, Type *Elem2Ty) {
444 assert(ElemTy->getScalarType() == Elem2Ty->getScalarType() &&
445 "Cannot form vector from incompatible scalar types");
446 Type *STy = ElemTy->getScalarType();
449 if (VectorType *VTy = dyn_cast<VectorType>(ElemTy)) {
450 numElem = VTy->getNumElements();
455 if (VectorType *VTy = dyn_cast<VectorType>(Elem2Ty)) {
456 numElem += VTy->getNumElements();
461 return VectorType::get(STy, numElem);
464 static inline void getInstructionTypes(Instruction *I,
465 Type *&T1, Type *&T2) {
466 if (isa<StoreInst>(I)) {
467 // For stores, it is the value type, not the pointer type that matters
468 // because the value is what will come from a vector register.
470 Value *IVal = cast<StoreInst>(I)->getValueOperand();
471 T1 = IVal->getType();
477 T2 = cast<CastInst>(I)->getSrcTy();
481 if (SelectInst *SI = dyn_cast<SelectInst>(I)) {
482 T2 = SI->getCondition()->getType();
483 } else if (ShuffleVectorInst *SI = dyn_cast<ShuffleVectorInst>(I)) {
484 T2 = SI->getOperand(0)->getType();
485 } else if (CmpInst *CI = dyn_cast<CmpInst>(I)) {
486 T2 = CI->getOperand(0)->getType();
490 // Returns the weight associated with the provided value. A chain of
491 // candidate pairs has a length given by the sum of the weights of its
492 // members (one weight per pair; the weight of each member of the pair
493 // is assumed to be the same). This length is then compared to the
494 // chain-length threshold to determine if a given chain is significant
495 // enough to be vectorized. The length is also used in comparing
496 // candidate chains where longer chains are considered to be better.
497 // Note: when this function returns 0, the resulting instructions are
498 // not actually fused.
499 inline size_t getDepthFactor(Value *V) {
500 // InsertElement and ExtractElement have a depth factor of zero. This is
501 // for two reasons: First, they cannot be usefully fused. Second, because
502 // the pass generates a lot of these, they can confuse the simple metric
503 // used to compare the trees in the next iteration. Thus, giving them a
504 // weight of zero allows the pass to essentially ignore them in
505 // subsequent iterations when looking for vectorization opportunities
506 // while still tracking dependency chains that flow through those
508 if (isa<InsertElementInst>(V) || isa<ExtractElementInst>(V))
511 // Give a load or store half of the required depth so that load/store
512 // pairs will vectorize.
513 if (!Config.NoMemOpBoost && (isa<LoadInst>(V) || isa<StoreInst>(V)))
514 return Config.ReqChainDepth/2;
519 // Returns the cost of the provided instruction using TTI.
520 // This does not handle loads and stores.
521 unsigned getInstrCost(unsigned Opcode, Type *T1, Type *T2) {
524 case Instruction::GetElementPtr:
525 // We mark this instruction as zero-cost because scalar GEPs are usually
526 // lowered to the intruction addressing mode. At the moment we don't
527 // generate vector GEPs.
529 case Instruction::Br:
530 return TTI->getCFInstrCost(Opcode);
531 case Instruction::PHI:
533 case Instruction::Add:
534 case Instruction::FAdd:
535 case Instruction::Sub:
536 case Instruction::FSub:
537 case Instruction::Mul:
538 case Instruction::FMul:
539 case Instruction::UDiv:
540 case Instruction::SDiv:
541 case Instruction::FDiv:
542 case Instruction::URem:
543 case Instruction::SRem:
544 case Instruction::FRem:
545 case Instruction::Shl:
546 case Instruction::LShr:
547 case Instruction::AShr:
548 case Instruction::And:
549 case Instruction::Or:
550 case Instruction::Xor:
551 return TTI->getArithmeticInstrCost(Opcode, T1);
552 case Instruction::Select:
553 case Instruction::ICmp:
554 case Instruction::FCmp:
555 return TTI->getCmpSelInstrCost(Opcode, T1, T2);
556 case Instruction::ZExt:
557 case Instruction::SExt:
558 case Instruction::FPToUI:
559 case Instruction::FPToSI:
560 case Instruction::FPExt:
561 case Instruction::PtrToInt:
562 case Instruction::IntToPtr:
563 case Instruction::SIToFP:
564 case Instruction::UIToFP:
565 case Instruction::Trunc:
566 case Instruction::FPTrunc:
567 case Instruction::BitCast:
568 case Instruction::ShuffleVector:
569 return TTI->getCastInstrCost(Opcode, T1, T2);
575 // This determines the relative offset of two loads or stores, returning
576 // true if the offset could be determined to be some constant value.
577 // For example, if OffsetInElmts == 1, then J accesses the memory directly
578 // after I; if OffsetInElmts == -1 then I accesses the memory
580 bool getPairPtrInfo(Instruction *I, Instruction *J,
581 Value *&IPtr, Value *&JPtr, unsigned &IAlignment, unsigned &JAlignment,
582 unsigned &IAddressSpace, unsigned &JAddressSpace,
583 int64_t &OffsetInElmts, bool ComputeOffset = true) {
585 if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
586 LoadInst *LJ = cast<LoadInst>(J);
587 IPtr = LI->getPointerOperand();
588 JPtr = LJ->getPointerOperand();
589 IAlignment = LI->getAlignment();
590 JAlignment = LJ->getAlignment();
591 IAddressSpace = LI->getPointerAddressSpace();
592 JAddressSpace = LJ->getPointerAddressSpace();
594 StoreInst *SI = cast<StoreInst>(I), *SJ = cast<StoreInst>(J);
595 IPtr = SI->getPointerOperand();
596 JPtr = SJ->getPointerOperand();
597 IAlignment = SI->getAlignment();
598 JAlignment = SJ->getAlignment();
599 IAddressSpace = SI->getPointerAddressSpace();
600 JAddressSpace = SJ->getPointerAddressSpace();
606 const SCEV *IPtrSCEV = SE->getSCEV(IPtr);
607 const SCEV *JPtrSCEV = SE->getSCEV(JPtr);
609 // If this is a trivial offset, then we'll get something like
610 // 1*sizeof(type). With target data, which we need anyway, this will get
611 // constant folded into a number.
612 const SCEV *OffsetSCEV = SE->getMinusSCEV(JPtrSCEV, IPtrSCEV);
613 if (const SCEVConstant *ConstOffSCEV =
614 dyn_cast<SCEVConstant>(OffsetSCEV)) {
615 ConstantInt *IntOff = ConstOffSCEV->getValue();
616 int64_t Offset = IntOff->getSExtValue();
618 Type *VTy = cast<PointerType>(IPtr->getType())->getElementType();
619 int64_t VTyTSS = (int64_t) TD->getTypeStoreSize(VTy);
621 Type *VTy2 = cast<PointerType>(JPtr->getType())->getElementType();
622 if (VTy != VTy2 && Offset < 0) {
623 int64_t VTy2TSS = (int64_t) TD->getTypeStoreSize(VTy2);
624 OffsetInElmts = Offset/VTy2TSS;
625 return (abs64(Offset) % VTy2TSS) == 0;
628 OffsetInElmts = Offset/VTyTSS;
629 return (abs64(Offset) % VTyTSS) == 0;
635 // Returns true if the provided CallInst represents an intrinsic that can
637 bool isVectorizableIntrinsic(CallInst* I) {
638 Function *F = I->getCalledFunction();
639 if (!F) return false;
641 Intrinsic::ID IID = (Intrinsic::ID) F->getIntrinsicID();
642 if (!IID) return false;
647 case Intrinsic::sqrt:
648 case Intrinsic::powi:
652 case Intrinsic::log2:
653 case Intrinsic::log10:
655 case Intrinsic::exp2:
657 return Config.VectorizeMath;
659 case Intrinsic::fmuladd:
660 return Config.VectorizeFMA;
664 // Returns true if J is the second element in some pair referenced by
665 // some multimap pair iterator pair.
666 template <typename V>
667 bool isSecondInIteratorPair(V J, std::pair<
668 typename std::multimap<V, V>::iterator,
669 typename std::multimap<V, V>::iterator> PairRange) {
670 for (typename std::multimap<V, V>::iterator K = PairRange.first;
671 K != PairRange.second; ++K)
672 if (K->second == J) return true;
677 bool isPureIEChain(InsertElementInst *IE) {
678 InsertElementInst *IENext = IE;
680 if (!isa<UndefValue>(IENext->getOperand(0)) &&
681 !isa<InsertElementInst>(IENext->getOperand(0))) {
685 dyn_cast<InsertElementInst>(IENext->getOperand(0))));
691 // This function implements one vectorization iteration on the provided
692 // basic block. It returns true if the block is changed.
693 bool BBVectorize::vectorizePairs(BasicBlock &BB, bool NonPow2Len) {
695 BasicBlock::iterator Start = BB.getFirstInsertionPt();
697 std::vector<Value *> AllPairableInsts;
698 DenseMap<Value *, Value *> AllChosenPairs;
699 DenseSet<ValuePair> AllFixedOrderPairs;
700 DenseMap<VPPair, unsigned> AllPairConnectionTypes;
701 std::multimap<ValuePair, ValuePair> AllConnectedPairs, AllConnectedPairDeps;
704 std::vector<Value *> PairableInsts;
705 std::multimap<Value *, Value *> CandidatePairs;
706 DenseSet<ValuePair> FixedOrderPairs;
707 DenseMap<ValuePair, int> CandidatePairCostSavings;
708 ShouldContinue = getCandidatePairs(BB, Start, CandidatePairs,
710 CandidatePairCostSavings,
711 PairableInsts, NonPow2Len);
712 if (PairableInsts.empty()) continue;
714 // Now we have a map of all of the pairable instructions and we need to
715 // select the best possible pairing. A good pairing is one such that the
716 // users of the pair are also paired. This defines a (directed) forest
717 // over the pairs such that two pairs are connected iff the second pair
720 // Note that it only matters that both members of the second pair use some
721 // element of the first pair (to allow for splatting).
723 std::multimap<ValuePair, ValuePair> ConnectedPairs, ConnectedPairDeps;
724 DenseMap<VPPair, unsigned> PairConnectionTypes;
725 computeConnectedPairs(CandidatePairs, PairableInsts, ConnectedPairs,
726 PairConnectionTypes);
727 if (ConnectedPairs.empty()) continue;
729 for (std::multimap<ValuePair, ValuePair>::iterator
730 I = ConnectedPairs.begin(), IE = ConnectedPairs.end();
732 ConnectedPairDeps.insert(VPPair(I->second, I->first));
735 // Build the pairable-instruction dependency map
736 DenseSet<ValuePair> PairableInstUsers;
737 buildDepMap(BB, CandidatePairs, PairableInsts, PairableInstUsers);
739 // There is now a graph of the connected pairs. For each variable, pick
740 // the pairing with the largest tree meeting the depth requirement on at
741 // least one branch. Then select all pairings that are part of that tree
742 // and remove them from the list of available pairings and pairable
745 DenseMap<Value *, Value *> ChosenPairs;
746 choosePairs(CandidatePairs, CandidatePairCostSavings,
747 PairableInsts, FixedOrderPairs, PairConnectionTypes,
748 ConnectedPairs, ConnectedPairDeps,
749 PairableInstUsers, ChosenPairs);
751 if (ChosenPairs.empty()) continue;
752 AllPairableInsts.insert(AllPairableInsts.end(), PairableInsts.begin(),
753 PairableInsts.end());
754 AllChosenPairs.insert(ChosenPairs.begin(), ChosenPairs.end());
756 // Only for the chosen pairs, propagate information on fixed-order pairs,
757 // pair connections, and their types to the data structures used by the
758 // pair fusion procedures.
759 for (DenseMap<Value *, Value *>::iterator I = ChosenPairs.begin(),
760 IE = ChosenPairs.end(); I != IE; ++I) {
761 if (FixedOrderPairs.count(*I))
762 AllFixedOrderPairs.insert(*I);
763 else if (FixedOrderPairs.count(ValuePair(I->second, I->first)))
764 AllFixedOrderPairs.insert(ValuePair(I->second, I->first));
766 for (DenseMap<Value *, Value *>::iterator J = ChosenPairs.begin();
768 DenseMap<VPPair, unsigned>::iterator K =
769 PairConnectionTypes.find(VPPair(*I, *J));
770 if (K != PairConnectionTypes.end()) {
771 AllPairConnectionTypes.insert(*K);
773 K = PairConnectionTypes.find(VPPair(*J, *I));
774 if (K != PairConnectionTypes.end())
775 AllPairConnectionTypes.insert(*K);
780 for (std::multimap<ValuePair, ValuePair>::iterator
781 I = ConnectedPairs.begin(), IE = ConnectedPairs.end();
783 if (AllPairConnectionTypes.count(*I)) {
784 AllConnectedPairs.insert(*I);
785 AllConnectedPairDeps.insert(VPPair(I->second, I->first));
788 } while (ShouldContinue);
790 if (AllChosenPairs.empty()) return false;
791 NumFusedOps += AllChosenPairs.size();
793 // A set of pairs has now been selected. It is now necessary to replace the
794 // paired instructions with vector instructions. For this procedure each
795 // operand must be replaced with a vector operand. This vector is formed
796 // by using build_vector on the old operands. The replaced values are then
797 // replaced with a vector_extract on the result. Subsequent optimization
798 // passes should coalesce the build/extract combinations.
800 fuseChosenPairs(BB, AllPairableInsts, AllChosenPairs, AllFixedOrderPairs,
801 AllPairConnectionTypes,
802 AllConnectedPairs, AllConnectedPairDeps);
804 // It is important to cleanup here so that future iterations of this
805 // function have less work to do.
806 (void) SimplifyInstructionsInBlock(&BB, TD, AA->getTargetLibraryInfo());
810 // This function returns true if the provided instruction is capable of being
811 // fused into a vector instruction. This determination is based only on the
812 // type and other attributes of the instruction.
813 bool BBVectorize::isInstVectorizable(Instruction *I,
814 bool &IsSimpleLoadStore) {
815 IsSimpleLoadStore = false;
817 if (CallInst *C = dyn_cast<CallInst>(I)) {
818 if (!isVectorizableIntrinsic(C))
820 } else if (LoadInst *L = dyn_cast<LoadInst>(I)) {
821 // Vectorize simple loads if possbile:
822 IsSimpleLoadStore = L->isSimple();
823 if (!IsSimpleLoadStore || !Config.VectorizeMemOps)
825 } else if (StoreInst *S = dyn_cast<StoreInst>(I)) {
826 // Vectorize simple stores if possbile:
827 IsSimpleLoadStore = S->isSimple();
828 if (!IsSimpleLoadStore || !Config.VectorizeMemOps)
830 } else if (CastInst *C = dyn_cast<CastInst>(I)) {
831 // We can vectorize casts, but not casts of pointer types, etc.
832 if (!Config.VectorizeCasts)
835 Type *SrcTy = C->getSrcTy();
836 if (!SrcTy->isSingleValueType())
839 Type *DestTy = C->getDestTy();
840 if (!DestTy->isSingleValueType())
842 } else if (isa<SelectInst>(I)) {
843 if (!Config.VectorizeSelect)
845 } else if (isa<CmpInst>(I)) {
846 if (!Config.VectorizeCmp)
848 } else if (GetElementPtrInst *G = dyn_cast<GetElementPtrInst>(I)) {
849 if (!Config.VectorizeGEP)
852 // Currently, vector GEPs exist only with one index.
853 if (G->getNumIndices() != 1)
855 } else if (!(I->isBinaryOp() || isa<ShuffleVectorInst>(I) ||
856 isa<ExtractElementInst>(I) || isa<InsertElementInst>(I))) {
860 // We can't vectorize memory operations without target data
861 if (TD == 0 && IsSimpleLoadStore)
865 getInstructionTypes(I, T1, T2);
867 // Not every type can be vectorized...
868 if (!(VectorType::isValidElementType(T1) || T1->isVectorTy()) ||
869 !(VectorType::isValidElementType(T2) || T2->isVectorTy()))
872 if (T1->getScalarSizeInBits() == 1) {
873 if (!Config.VectorizeBools)
876 if (!Config.VectorizeInts && T1->isIntOrIntVectorTy())
880 if (T2->getScalarSizeInBits() == 1) {
881 if (!Config.VectorizeBools)
884 if (!Config.VectorizeInts && T2->isIntOrIntVectorTy())
888 if (!Config.VectorizeFloats
889 && (T1->isFPOrFPVectorTy() || T2->isFPOrFPVectorTy()))
892 // Don't vectorize target-specific types.
893 if (T1->isX86_FP80Ty() || T1->isPPC_FP128Ty() || T1->isX86_MMXTy())
895 if (T2->isX86_FP80Ty() || T2->isPPC_FP128Ty() || T2->isX86_MMXTy())
898 if ((!Config.VectorizePointers || TD == 0) &&
899 (T1->getScalarType()->isPointerTy() ||
900 T2->getScalarType()->isPointerTy()))
903 if (!TTI && (T1->getPrimitiveSizeInBits() >= Config.VectorBits ||
904 T2->getPrimitiveSizeInBits() >= Config.VectorBits))
910 // This function returns true if the two provided instructions are compatible
911 // (meaning that they can be fused into a vector instruction). This assumes
912 // that I has already been determined to be vectorizable and that J is not
913 // in the use tree of I.
914 bool BBVectorize::areInstsCompatible(Instruction *I, Instruction *J,
915 bool IsSimpleLoadStore, bool NonPow2Len,
916 int &CostSavings, int &FixedOrder) {
917 DEBUG(if (DebugInstructionExamination) dbgs() << "BBV: looking at " << *I <<
918 " <-> " << *J << "\n");
923 // Loads and stores can be merged if they have different alignments,
924 // but are otherwise the same.
925 if (!J->isSameOperationAs(I, Instruction::CompareIgnoringAlignment |
926 (NonPow2Len ? Instruction::CompareUsingScalarTypes : 0)))
929 Type *IT1, *IT2, *JT1, *JT2;
930 getInstructionTypes(I, IT1, IT2);
931 getInstructionTypes(J, JT1, JT2);
932 unsigned MaxTypeBits = std::max(
933 IT1->getPrimitiveSizeInBits() + JT1->getPrimitiveSizeInBits(),
934 IT2->getPrimitiveSizeInBits() + JT2->getPrimitiveSizeInBits());
935 if (!TTI && MaxTypeBits > Config.VectorBits)
938 // FIXME: handle addsub-type operations!
940 if (IsSimpleLoadStore) {
942 unsigned IAlignment, JAlignment, IAddressSpace, JAddressSpace;
943 int64_t OffsetInElmts = 0;
944 if (getPairPtrInfo(I, J, IPtr, JPtr, IAlignment, JAlignment,
945 IAddressSpace, JAddressSpace,
946 OffsetInElmts) && abs64(OffsetInElmts) == 1) {
947 FixedOrder = (int) OffsetInElmts;
948 unsigned BottomAlignment = IAlignment;
949 if (OffsetInElmts < 0) BottomAlignment = JAlignment;
951 Type *aTypeI = isa<StoreInst>(I) ?
952 cast<StoreInst>(I)->getValueOperand()->getType() : I->getType();
953 Type *aTypeJ = isa<StoreInst>(J) ?
954 cast<StoreInst>(J)->getValueOperand()->getType() : J->getType();
955 Type *VType = getVecTypeForPair(aTypeI, aTypeJ);
957 if (Config.AlignedOnly) {
958 // An aligned load or store is possible only if the instruction
959 // with the lower offset has an alignment suitable for the
962 unsigned VecAlignment = TD->getPrefTypeAlignment(VType);
963 if (BottomAlignment < VecAlignment)
968 unsigned ICost = TTI->getMemoryOpCost(I->getOpcode(), aTypeI,
969 IAlignment, IAddressSpace);
970 unsigned JCost = TTI->getMemoryOpCost(J->getOpcode(), aTypeJ,
971 JAlignment, JAddressSpace);
972 unsigned VCost = TTI->getMemoryOpCost(I->getOpcode(), VType,
975 if (VCost > ICost + JCost)
978 // We don't want to fuse to a type that will be split, even
979 // if the two input types will also be split and there is no other
981 unsigned VParts = TTI->getNumberOfParts(VType);
984 else if (!VParts && VCost == ICost + JCost)
987 CostSavings = ICost + JCost - VCost;
993 unsigned ICost = getInstrCost(I->getOpcode(), IT1, IT2);
994 unsigned JCost = getInstrCost(J->getOpcode(), JT1, JT2);
995 Type *VT1 = getVecTypeForPair(IT1, JT1),
996 *VT2 = getVecTypeForPair(IT2, JT2);
998 // Note that this procedure is incorrect for insert and extract element
999 // instructions (because combining these often results in a shuffle),
1000 // but this cost is ignored (because insert and extract element
1001 // instructions are assigned a zero depth factor and are not really
1002 // fused in general).
1003 unsigned VCost = getInstrCost(I->getOpcode(), VT1, VT2);
1005 if (VCost > ICost + JCost)
1008 // We don't want to fuse to a type that will be split, even
1009 // if the two input types will also be split and there is no other
1011 unsigned VParts1 = TTI->getNumberOfParts(VT1),
1012 VParts2 = TTI->getNumberOfParts(VT2);
1013 if (VParts1 > 1 || VParts2 > 1)
1015 else if ((!VParts1 || !VParts2) && VCost == ICost + JCost)
1018 CostSavings = ICost + JCost - VCost;
1021 // The powi intrinsic is special because only the first argument is
1022 // vectorized, the second arguments must be equal.
1023 CallInst *CI = dyn_cast<CallInst>(I);
1025 if (CI && (FI = CI->getCalledFunction())) {
1026 Intrinsic::ID IID = (Intrinsic::ID) FI->getIntrinsicID();
1027 if (IID == Intrinsic::powi) {
1028 Value *A1I = CI->getArgOperand(1),
1029 *A1J = cast<CallInst>(J)->getArgOperand(1);
1030 const SCEV *A1ISCEV = SE->getSCEV(A1I),
1031 *A1JSCEV = SE->getSCEV(A1J);
1032 return (A1ISCEV == A1JSCEV);
1036 SmallVector<Type*, 4> Tys;
1037 for (unsigned i = 0, ie = CI->getNumArgOperands(); i != ie; ++i)
1038 Tys.push_back(CI->getArgOperand(i)->getType());
1039 unsigned ICost = TTI->getIntrinsicInstrCost(IID, IT1, Tys);
1042 CallInst *CJ = cast<CallInst>(J);
1043 for (unsigned i = 0, ie = CJ->getNumArgOperands(); i != ie; ++i)
1044 Tys.push_back(CJ->getArgOperand(i)->getType());
1045 unsigned JCost = TTI->getIntrinsicInstrCost(IID, JT1, Tys);
1048 assert(CI->getNumArgOperands() == CJ->getNumArgOperands() &&
1049 "Intrinsic argument counts differ");
1050 for (unsigned i = 0, ie = CI->getNumArgOperands(); i != ie; ++i) {
1051 if (IID == Intrinsic::powi && i == 1)
1052 Tys.push_back(CI->getArgOperand(i)->getType());
1054 Tys.push_back(getVecTypeForPair(CI->getArgOperand(i)->getType(),
1055 CJ->getArgOperand(i)->getType()));
1058 Type *RetTy = getVecTypeForPair(IT1, JT1);
1059 unsigned VCost = TTI->getIntrinsicInstrCost(IID, RetTy, Tys);
1061 if (VCost > ICost + JCost)
1064 // We don't want to fuse to a type that will be split, even
1065 // if the two input types will also be split and there is no other
1067 unsigned RetParts = TTI->getNumberOfParts(RetTy);
1070 else if (!RetParts && VCost == ICost + JCost)
1073 for (unsigned i = 0, ie = CI->getNumArgOperands(); i != ie; ++i) {
1074 if (!Tys[i]->isVectorTy())
1077 unsigned NumParts = TTI->getNumberOfParts(Tys[i]);
1080 else if (!NumParts && VCost == ICost + JCost)
1084 CostSavings = ICost + JCost - VCost;
1091 // Figure out whether or not J uses I and update the users and write-set
1092 // structures associated with I. Specifically, Users represents the set of
1093 // instructions that depend on I. WriteSet represents the set
1094 // of memory locations that are dependent on I. If UpdateUsers is true,
1095 // and J uses I, then Users is updated to contain J and WriteSet is updated
1096 // to contain any memory locations to which J writes. The function returns
1097 // true if J uses I. By default, alias analysis is used to determine
1098 // whether J reads from memory that overlaps with a location in WriteSet.
1099 // If LoadMoveSet is not null, then it is a previously-computed multimap
1100 // where the key is the memory-based user instruction and the value is
1101 // the instruction to be compared with I. So, if LoadMoveSet is provided,
1102 // then the alias analysis is not used. This is necessary because this
1103 // function is called during the process of moving instructions during
1104 // vectorization and the results of the alias analysis are not stable during
1106 bool BBVectorize::trackUsesOfI(DenseSet<Value *> &Users,
1107 AliasSetTracker &WriteSet, Instruction *I,
1108 Instruction *J, bool UpdateUsers,
1109 std::multimap<Value *, Value *> *LoadMoveSet) {
1112 // This instruction may already be marked as a user due, for example, to
1113 // being a member of a selected pair.
1118 for (User::op_iterator JU = J->op_begin(), JE = J->op_end();
1121 if (I == V || Users.count(V)) {
1126 if (!UsesI && J->mayReadFromMemory()) {
1128 VPIteratorPair JPairRange = LoadMoveSet->equal_range(J);
1129 UsesI = isSecondInIteratorPair<Value*>(I, JPairRange);
1131 for (AliasSetTracker::iterator W = WriteSet.begin(),
1132 WE = WriteSet.end(); W != WE; ++W) {
1133 if (W->aliasesUnknownInst(J, *AA)) {
1141 if (UsesI && UpdateUsers) {
1142 if (J->mayWriteToMemory()) WriteSet.add(J);
1149 // This function iterates over all instruction pairs in the provided
1150 // basic block and collects all candidate pairs for vectorization.
1151 bool BBVectorize::getCandidatePairs(BasicBlock &BB,
1152 BasicBlock::iterator &Start,
1153 std::multimap<Value *, Value *> &CandidatePairs,
1154 DenseSet<ValuePair> &FixedOrderPairs,
1155 DenseMap<ValuePair, int> &CandidatePairCostSavings,
1156 std::vector<Value *> &PairableInsts, bool NonPow2Len) {
1157 BasicBlock::iterator E = BB.end();
1158 if (Start == E) return false;
1160 bool ShouldContinue = false, IAfterStart = false;
1161 for (BasicBlock::iterator I = Start++; I != E; ++I) {
1162 if (I == Start) IAfterStart = true;
1164 bool IsSimpleLoadStore;
1165 if (!isInstVectorizable(I, IsSimpleLoadStore)) continue;
1167 // Look for an instruction with which to pair instruction *I...
1168 DenseSet<Value *> Users;
1169 AliasSetTracker WriteSet(*AA);
1170 bool JAfterStart = IAfterStart;
1171 BasicBlock::iterator J = llvm::next(I);
1172 for (unsigned ss = 0; J != E && ss <= Config.SearchLimit; ++J, ++ss) {
1173 if (J == Start) JAfterStart = true;
1175 // Determine if J uses I, if so, exit the loop.
1176 bool UsesI = trackUsesOfI(Users, WriteSet, I, J, !Config.FastDep);
1177 if (Config.FastDep) {
1178 // Note: For this heuristic to be effective, independent operations
1179 // must tend to be intermixed. This is likely to be true from some
1180 // kinds of grouped loop unrolling (but not the generic LLVM pass),
1181 // but otherwise may require some kind of reordering pass.
1183 // When using fast dependency analysis,
1184 // stop searching after first use:
1187 if (UsesI) continue;
1190 // J does not use I, and comes before the first use of I, so it can be
1191 // merged with I if the instructions are compatible.
1192 int CostSavings, FixedOrder;
1193 if (!areInstsCompatible(I, J, IsSimpleLoadStore, NonPow2Len,
1194 CostSavings, FixedOrder)) continue;
1196 // J is a candidate for merging with I.
1197 if (!PairableInsts.size() ||
1198 PairableInsts[PairableInsts.size()-1] != I) {
1199 PairableInsts.push_back(I);
1202 CandidatePairs.insert(ValuePair(I, J));
1204 CandidatePairCostSavings.insert(ValuePairWithCost(ValuePair(I, J),
1207 if (FixedOrder == 1)
1208 FixedOrderPairs.insert(ValuePair(I, J));
1209 else if (FixedOrder == -1)
1210 FixedOrderPairs.insert(ValuePair(J, I));
1212 // The next call to this function must start after the last instruction
1213 // selected during this invocation.
1215 Start = llvm::next(J);
1216 IAfterStart = JAfterStart = false;
1219 DEBUG(if (DebugCandidateSelection) dbgs() << "BBV: candidate pair "
1220 << *I << " <-> " << *J << " (cost savings: " <<
1221 CostSavings << ")\n");
1223 // If we have already found too many pairs, break here and this function
1224 // will be called again starting after the last instruction selected
1225 // during this invocation.
1226 if (PairableInsts.size() >= Config.MaxInsts) {
1227 ShouldContinue = true;
1236 DEBUG(dbgs() << "BBV: found " << PairableInsts.size()
1237 << " instructions with candidate pairs\n");
1239 return ShouldContinue;
1242 // Finds candidate pairs connected to the pair P = <PI, PJ>. This means that
1243 // it looks for pairs such that both members have an input which is an
1244 // output of PI or PJ.
1245 void BBVectorize::computePairsConnectedTo(
1246 std::multimap<Value *, Value *> &CandidatePairs,
1247 std::vector<Value *> &PairableInsts,
1248 std::multimap<ValuePair, ValuePair> &ConnectedPairs,
1249 DenseMap<VPPair, unsigned> &PairConnectionTypes,
1253 // For each possible pairing for this variable, look at the uses of
1254 // the first value...
1255 for (Value::use_iterator I = P.first->use_begin(),
1256 E = P.first->use_end(); I != E; ++I) {
1257 if (isa<LoadInst>(*I)) {
1258 // A pair cannot be connected to a load because the load only takes one
1259 // operand (the address) and it is a scalar even after vectorization.
1261 } else if ((SI = dyn_cast<StoreInst>(*I)) &&
1262 P.first == SI->getPointerOperand()) {
1263 // Similarly, a pair cannot be connected to a store through its
1268 VPIteratorPair IPairRange = CandidatePairs.equal_range(*I);
1270 // For each use of the first variable, look for uses of the second
1272 for (Value::use_iterator J = P.second->use_begin(),
1273 E2 = P.second->use_end(); J != E2; ++J) {
1274 if ((SJ = dyn_cast<StoreInst>(*J)) &&
1275 P.second == SJ->getPointerOperand())
1278 VPIteratorPair JPairRange = CandidatePairs.equal_range(*J);
1281 if (isSecondInIteratorPair<Value*>(*J, IPairRange)) {
1282 VPPair VP(P, ValuePair(*I, *J));
1283 ConnectedPairs.insert(VP);
1284 PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionDirect));
1288 if (isSecondInIteratorPair<Value*>(*I, JPairRange)) {
1289 VPPair VP(P, ValuePair(*J, *I));
1290 ConnectedPairs.insert(VP);
1291 PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionSwap));
1295 if (Config.SplatBreaksChain) continue;
1296 // Look for cases where just the first value in the pair is used by
1297 // both members of another pair (splatting).
1298 for (Value::use_iterator J = P.first->use_begin(); J != E; ++J) {
1299 if ((SJ = dyn_cast<StoreInst>(*J)) &&
1300 P.first == SJ->getPointerOperand())
1303 if (isSecondInIteratorPair<Value*>(*J, IPairRange)) {
1304 VPPair VP(P, ValuePair(*I, *J));
1305 ConnectedPairs.insert(VP);
1306 PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionSplat));
1311 if (Config.SplatBreaksChain) return;
1312 // Look for cases where just the second value in the pair is used by
1313 // both members of another pair (splatting).
1314 for (Value::use_iterator I = P.second->use_begin(),
1315 E = P.second->use_end(); I != E; ++I) {
1316 if (isa<LoadInst>(*I))
1318 else if ((SI = dyn_cast<StoreInst>(*I)) &&
1319 P.second == SI->getPointerOperand())
1322 VPIteratorPair IPairRange = CandidatePairs.equal_range(*I);
1324 for (Value::use_iterator J = P.second->use_begin(); J != E; ++J) {
1325 if ((SJ = dyn_cast<StoreInst>(*J)) &&
1326 P.second == SJ->getPointerOperand())
1329 if (isSecondInIteratorPair<Value*>(*J, IPairRange)) {
1330 VPPair VP(P, ValuePair(*I, *J));
1331 ConnectedPairs.insert(VP);
1332 PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionSplat));
1338 // This function figures out which pairs are connected. Two pairs are
1339 // connected if some output of the first pair forms an input to both members
1340 // of the second pair.
1341 void BBVectorize::computeConnectedPairs(
1342 std::multimap<Value *, Value *> &CandidatePairs,
1343 std::vector<Value *> &PairableInsts,
1344 std::multimap<ValuePair, ValuePair> &ConnectedPairs,
1345 DenseMap<VPPair, unsigned> &PairConnectionTypes) {
1347 for (std::vector<Value *>::iterator PI = PairableInsts.begin(),
1348 PE = PairableInsts.end(); PI != PE; ++PI) {
1349 VPIteratorPair choiceRange = CandidatePairs.equal_range(*PI);
1351 for (std::multimap<Value *, Value *>::iterator P = choiceRange.first;
1352 P != choiceRange.second; ++P)
1353 computePairsConnectedTo(CandidatePairs, PairableInsts,
1354 ConnectedPairs, PairConnectionTypes, *P);
1357 DEBUG(dbgs() << "BBV: found " << ConnectedPairs.size()
1358 << " pair connections.\n");
1361 // This function builds a set of use tuples such that <A, B> is in the set
1362 // if B is in the use tree of A. If B is in the use tree of A, then B
1363 // depends on the output of A.
1364 void BBVectorize::buildDepMap(
1366 std::multimap<Value *, Value *> &CandidatePairs,
1367 std::vector<Value *> &PairableInsts,
1368 DenseSet<ValuePair> &PairableInstUsers) {
1369 DenseSet<Value *> IsInPair;
1370 for (std::multimap<Value *, Value *>::iterator C = CandidatePairs.begin(),
1371 E = CandidatePairs.end(); C != E; ++C) {
1372 IsInPair.insert(C->first);
1373 IsInPair.insert(C->second);
1376 // Iterate through the basic block, recording all users of each
1377 // pairable instruction.
1379 BasicBlock::iterator E = BB.end();
1380 for (BasicBlock::iterator I = BB.getFirstInsertionPt(); I != E; ++I) {
1381 if (IsInPair.find(I) == IsInPair.end()) continue;
1383 DenseSet<Value *> Users;
1384 AliasSetTracker WriteSet(*AA);
1385 for (BasicBlock::iterator J = llvm::next(I); J != E; ++J)
1386 (void) trackUsesOfI(Users, WriteSet, I, J);
1388 for (DenseSet<Value *>::iterator U = Users.begin(), E = Users.end();
1390 PairableInstUsers.insert(ValuePair(I, *U));
1394 // Returns true if an input to pair P is an output of pair Q and also an
1395 // input of pair Q is an output of pair P. If this is the case, then these
1396 // two pairs cannot be simultaneously fused.
1397 bool BBVectorize::pairsConflict(ValuePair P, ValuePair Q,
1398 DenseSet<ValuePair> &PairableInstUsers,
1399 std::multimap<ValuePair, ValuePair> *PairableInstUserMap) {
1400 // Two pairs are in conflict if they are mutual Users of eachother.
1401 bool QUsesP = PairableInstUsers.count(ValuePair(P.first, Q.first)) ||
1402 PairableInstUsers.count(ValuePair(P.first, Q.second)) ||
1403 PairableInstUsers.count(ValuePair(P.second, Q.first)) ||
1404 PairableInstUsers.count(ValuePair(P.second, Q.second));
1405 bool PUsesQ = PairableInstUsers.count(ValuePair(Q.first, P.first)) ||
1406 PairableInstUsers.count(ValuePair(Q.first, P.second)) ||
1407 PairableInstUsers.count(ValuePair(Q.second, P.first)) ||
1408 PairableInstUsers.count(ValuePair(Q.second, P.second));
1409 if (PairableInstUserMap) {
1410 // FIXME: The expensive part of the cycle check is not so much the cycle
1411 // check itself but this edge insertion procedure. This needs some
1412 // profiling and probably a different data structure (same is true of
1413 // most uses of std::multimap).
1415 VPPIteratorPair QPairRange = PairableInstUserMap->equal_range(Q);
1416 if (!isSecondInIteratorPair(P, QPairRange))
1417 PairableInstUserMap->insert(VPPair(Q, P));
1420 VPPIteratorPair PPairRange = PairableInstUserMap->equal_range(P);
1421 if (!isSecondInIteratorPair(Q, PPairRange))
1422 PairableInstUserMap->insert(VPPair(P, Q));
1426 return (QUsesP && PUsesQ);
1429 // This function walks the use graph of current pairs to see if, starting
1430 // from P, the walk returns to P.
1431 bool BBVectorize::pairWillFormCycle(ValuePair P,
1432 std::multimap<ValuePair, ValuePair> &PairableInstUserMap,
1433 DenseSet<ValuePair> &CurrentPairs) {
1434 DEBUG(if (DebugCycleCheck)
1435 dbgs() << "BBV: starting cycle check for : " << *P.first << " <-> "
1436 << *P.second << "\n");
1437 // A lookup table of visisted pairs is kept because the PairableInstUserMap
1438 // contains non-direct associations.
1439 DenseSet<ValuePair> Visited;
1440 SmallVector<ValuePair, 32> Q;
1441 // General depth-first post-order traversal:
1444 ValuePair QTop = Q.pop_back_val();
1445 Visited.insert(QTop);
1447 DEBUG(if (DebugCycleCheck)
1448 dbgs() << "BBV: cycle check visiting: " << *QTop.first << " <-> "
1449 << *QTop.second << "\n");
1450 VPPIteratorPair QPairRange = PairableInstUserMap.equal_range(QTop);
1451 for (std::multimap<ValuePair, ValuePair>::iterator C = QPairRange.first;
1452 C != QPairRange.second; ++C) {
1453 if (C->second == P) {
1455 << "BBV: rejected to prevent non-trivial cycle formation: "
1456 << *C->first.first << " <-> " << *C->first.second << "\n");
1460 if (CurrentPairs.count(C->second) && !Visited.count(C->second))
1461 Q.push_back(C->second);
1463 } while (!Q.empty());
1468 // This function builds the initial tree of connected pairs with the
1469 // pair J at the root.
1470 void BBVectorize::buildInitialTreeFor(
1471 std::multimap<Value *, Value *> &CandidatePairs,
1472 std::vector<Value *> &PairableInsts,
1473 std::multimap<ValuePair, ValuePair> &ConnectedPairs,
1474 DenseSet<ValuePair> &PairableInstUsers,
1475 DenseMap<Value *, Value *> &ChosenPairs,
1476 DenseMap<ValuePair, size_t> &Tree, ValuePair J) {
1477 // Each of these pairs is viewed as the root node of a Tree. The Tree
1478 // is then walked (depth-first). As this happens, we keep track of
1479 // the pairs that compose the Tree and the maximum depth of the Tree.
1480 SmallVector<ValuePairWithDepth, 32> Q;
1481 // General depth-first post-order traversal:
1482 Q.push_back(ValuePairWithDepth(J, getDepthFactor(J.first)));
1484 ValuePairWithDepth QTop = Q.back();
1486 // Push each child onto the queue:
1487 bool MoreChildren = false;
1488 size_t MaxChildDepth = QTop.second;
1489 VPPIteratorPair qtRange = ConnectedPairs.equal_range(QTop.first);
1490 for (std::multimap<ValuePair, ValuePair>::iterator k = qtRange.first;
1491 k != qtRange.second; ++k) {
1492 // Make sure that this child pair is still a candidate:
1493 bool IsStillCand = false;
1494 VPIteratorPair checkRange =
1495 CandidatePairs.equal_range(k->second.first);
1496 for (std::multimap<Value *, Value *>::iterator m = checkRange.first;
1497 m != checkRange.second; ++m) {
1498 if (m->second == k->second.second) {
1505 DenseMap<ValuePair, size_t>::iterator C = Tree.find(k->second);
1506 if (C == Tree.end()) {
1507 size_t d = getDepthFactor(k->second.first);
1508 Q.push_back(ValuePairWithDepth(k->second, QTop.second+d));
1509 MoreChildren = true;
1511 MaxChildDepth = std::max(MaxChildDepth, C->second);
1516 if (!MoreChildren) {
1517 // Record the current pair as part of the Tree:
1518 Tree.insert(ValuePairWithDepth(QTop.first, MaxChildDepth));
1521 } while (!Q.empty());
1524 // Given some initial tree, prune it by removing conflicting pairs (pairs
1525 // that cannot be simultaneously chosen for vectorization).
1526 void BBVectorize::pruneTreeFor(
1527 std::multimap<Value *, Value *> &CandidatePairs,
1528 std::vector<Value *> &PairableInsts,
1529 std::multimap<ValuePair, ValuePair> &ConnectedPairs,
1530 DenseSet<ValuePair> &PairableInstUsers,
1531 std::multimap<ValuePair, ValuePair> &PairableInstUserMap,
1532 DenseMap<Value *, Value *> &ChosenPairs,
1533 DenseMap<ValuePair, size_t> &Tree,
1534 DenseSet<ValuePair> &PrunedTree, ValuePair J,
1535 bool UseCycleCheck) {
1536 SmallVector<ValuePairWithDepth, 32> Q;
1537 // General depth-first post-order traversal:
1538 Q.push_back(ValuePairWithDepth(J, getDepthFactor(J.first)));
1540 ValuePairWithDepth QTop = Q.pop_back_val();
1541 PrunedTree.insert(QTop.first);
1543 // Visit each child, pruning as necessary...
1544 SmallVector<ValuePairWithDepth, 8> BestChildren;
1545 VPPIteratorPair QTopRange = ConnectedPairs.equal_range(QTop.first);
1546 for (std::multimap<ValuePair, ValuePair>::iterator K = QTopRange.first;
1547 K != QTopRange.second; ++K) {
1548 DenseMap<ValuePair, size_t>::iterator C = Tree.find(K->second);
1549 if (C == Tree.end()) continue;
1551 // This child is in the Tree, now we need to make sure it is the
1552 // best of any conflicting children. There could be multiple
1553 // conflicting children, so first, determine if we're keeping
1554 // this child, then delete conflicting children as necessary.
1556 // It is also necessary to guard against pairing-induced
1557 // dependencies. Consider instructions a .. x .. y .. b
1558 // such that (a,b) are to be fused and (x,y) are to be fused
1559 // but a is an input to x and b is an output from y. This
1560 // means that y cannot be moved after b but x must be moved
1561 // after b for (a,b) to be fused. In other words, after
1562 // fusing (a,b) we have y .. a/b .. x where y is an input
1563 // to a/b and x is an output to a/b: x and y can no longer
1564 // be legally fused. To prevent this condition, we must
1565 // make sure that a child pair added to the Tree is not
1566 // both an input and output of an already-selected pair.
1568 // Pairing-induced dependencies can also form from more complicated
1569 // cycles. The pair vs. pair conflicts are easy to check, and so
1570 // that is done explicitly for "fast rejection", and because for
1571 // child vs. child conflicts, we may prefer to keep the current
1572 // pair in preference to the already-selected child.
1573 DenseSet<ValuePair> CurrentPairs;
1576 for (SmallVector<ValuePairWithDepth, 8>::iterator C2
1577 = BestChildren.begin(), E2 = BestChildren.end();
1579 if (C2->first.first == C->first.first ||
1580 C2->first.first == C->first.second ||
1581 C2->first.second == C->first.first ||
1582 C2->first.second == C->first.second ||
1583 pairsConflict(C2->first, C->first, PairableInstUsers,
1584 UseCycleCheck ? &PairableInstUserMap : 0)) {
1585 if (C2->second >= C->second) {
1590 CurrentPairs.insert(C2->first);
1593 if (!CanAdd) continue;
1595 // Even worse, this child could conflict with another node already
1596 // selected for the Tree. If that is the case, ignore this child.
1597 for (DenseSet<ValuePair>::iterator T = PrunedTree.begin(),
1598 E2 = PrunedTree.end(); T != E2; ++T) {
1599 if (T->first == C->first.first ||
1600 T->first == C->first.second ||
1601 T->second == C->first.first ||
1602 T->second == C->first.second ||
1603 pairsConflict(*T, C->first, PairableInstUsers,
1604 UseCycleCheck ? &PairableInstUserMap : 0)) {
1609 CurrentPairs.insert(*T);
1611 if (!CanAdd) continue;
1613 // And check the queue too...
1614 for (SmallVector<ValuePairWithDepth, 32>::iterator C2 = Q.begin(),
1615 E2 = Q.end(); C2 != E2; ++C2) {
1616 if (C2->first.first == C->first.first ||
1617 C2->first.first == C->first.second ||
1618 C2->first.second == C->first.first ||
1619 C2->first.second == C->first.second ||
1620 pairsConflict(C2->first, C->first, PairableInstUsers,
1621 UseCycleCheck ? &PairableInstUserMap : 0)) {
1626 CurrentPairs.insert(C2->first);
1628 if (!CanAdd) continue;
1630 // Last but not least, check for a conflict with any of the
1631 // already-chosen pairs.
1632 for (DenseMap<Value *, Value *>::iterator C2 =
1633 ChosenPairs.begin(), E2 = ChosenPairs.end();
1635 if (pairsConflict(*C2, C->first, PairableInstUsers,
1636 UseCycleCheck ? &PairableInstUserMap : 0)) {
1641 CurrentPairs.insert(*C2);
1643 if (!CanAdd) continue;
1645 // To check for non-trivial cycles formed by the addition of the
1646 // current pair we've formed a list of all relevant pairs, now use a
1647 // graph walk to check for a cycle. We start from the current pair and
1648 // walk the use tree to see if we again reach the current pair. If we
1649 // do, then the current pair is rejected.
1651 // FIXME: It may be more efficient to use a topological-ordering
1652 // algorithm to improve the cycle check. This should be investigated.
1653 if (UseCycleCheck &&
1654 pairWillFormCycle(C->first, PairableInstUserMap, CurrentPairs))
1657 // This child can be added, but we may have chosen it in preference
1658 // to an already-selected child. Check for this here, and if a
1659 // conflict is found, then remove the previously-selected child
1660 // before adding this one in its place.
1661 for (SmallVector<ValuePairWithDepth, 8>::iterator C2
1662 = BestChildren.begin(); C2 != BestChildren.end();) {
1663 if (C2->first.first == C->first.first ||
1664 C2->first.first == C->first.second ||
1665 C2->first.second == C->first.first ||
1666 C2->first.second == C->first.second ||
1667 pairsConflict(C2->first, C->first, PairableInstUsers))
1668 C2 = BestChildren.erase(C2);
1673 BestChildren.push_back(ValuePairWithDepth(C->first, C->second));
1676 for (SmallVector<ValuePairWithDepth, 8>::iterator C
1677 = BestChildren.begin(), E2 = BestChildren.end();
1679 size_t DepthF = getDepthFactor(C->first.first);
1680 Q.push_back(ValuePairWithDepth(C->first, QTop.second+DepthF));
1682 } while (!Q.empty());
1685 // This function finds the best tree of mututally-compatible connected
1686 // pairs, given the choice of root pairs as an iterator range.
1687 void BBVectorize::findBestTreeFor(
1688 std::multimap<Value *, Value *> &CandidatePairs,
1689 DenseMap<ValuePair, int> &CandidatePairCostSavings,
1690 std::vector<Value *> &PairableInsts,
1691 DenseSet<ValuePair> &FixedOrderPairs,
1692 DenseMap<VPPair, unsigned> &PairConnectionTypes,
1693 std::multimap<ValuePair, ValuePair> &ConnectedPairs,
1694 std::multimap<ValuePair, ValuePair> &ConnectedPairDeps,
1695 DenseSet<ValuePair> &PairableInstUsers,
1696 std::multimap<ValuePair, ValuePair> &PairableInstUserMap,
1697 DenseMap<Value *, Value *> &ChosenPairs,
1698 DenseSet<ValuePair> &BestTree, size_t &BestMaxDepth,
1699 int &BestEffSize, VPIteratorPair ChoiceRange,
1700 bool UseCycleCheck) {
1701 for (std::multimap<Value *, Value *>::iterator J = ChoiceRange.first;
1702 J != ChoiceRange.second; ++J) {
1704 // Before going any further, make sure that this pair does not
1705 // conflict with any already-selected pairs (see comment below
1706 // near the Tree pruning for more details).
1707 DenseSet<ValuePair> ChosenPairSet;
1708 bool DoesConflict = false;
1709 for (DenseMap<Value *, Value *>::iterator C = ChosenPairs.begin(),
1710 E = ChosenPairs.end(); C != E; ++C) {
1711 if (pairsConflict(*C, *J, PairableInstUsers,
1712 UseCycleCheck ? &PairableInstUserMap : 0)) {
1713 DoesConflict = true;
1717 ChosenPairSet.insert(*C);
1719 if (DoesConflict) continue;
1721 if (UseCycleCheck &&
1722 pairWillFormCycle(*J, PairableInstUserMap, ChosenPairSet))
1725 DenseMap<ValuePair, size_t> Tree;
1726 buildInitialTreeFor(CandidatePairs, PairableInsts, ConnectedPairs,
1727 PairableInstUsers, ChosenPairs, Tree, *J);
1729 // Because we'll keep the child with the largest depth, the largest
1730 // depth is still the same in the unpruned Tree.
1731 size_t MaxDepth = Tree.lookup(*J);
1733 DEBUG(if (DebugPairSelection) dbgs() << "BBV: found Tree for pair {"
1734 << *J->first << " <-> " << *J->second << "} of depth " <<
1735 MaxDepth << " and size " << Tree.size() << "\n");
1737 // At this point the Tree has been constructed, but, may contain
1738 // contradictory children (meaning that different children of
1739 // some tree node may be attempting to fuse the same instruction).
1740 // So now we walk the tree again, in the case of a conflict,
1741 // keep only the child with the largest depth. To break a tie,
1742 // favor the first child.
1744 DenseSet<ValuePair> PrunedTree;
1745 pruneTreeFor(CandidatePairs, PairableInsts, ConnectedPairs,
1746 PairableInstUsers, PairableInstUserMap, ChosenPairs, Tree,
1747 PrunedTree, *J, UseCycleCheck);
1751 DenseSet<Value *> PrunedTreeInstrs;
1752 for (DenseSet<ValuePair>::iterator S = PrunedTree.begin(),
1753 E = PrunedTree.end(); S != E; ++S) {
1754 PrunedTreeInstrs.insert(S->first);
1755 PrunedTreeInstrs.insert(S->second);
1758 // The set of pairs that have already contributed to the total cost.
1759 DenseSet<ValuePair> IncomingPairs;
1761 // If the cost model were perfect, this might not be necessary; but we
1762 // need to make sure that we don't get stuck vectorizing our own
1764 bool HasNontrivialInsts = false;
1766 // The node weights represent the cost savings associated with
1767 // fusing the pair of instructions.
1768 for (DenseSet<ValuePair>::iterator S = PrunedTree.begin(),
1769 E = PrunedTree.end(); S != E; ++S) {
1770 if (!isa<ShuffleVectorInst>(S->first) &&
1771 !isa<InsertElementInst>(S->first) &&
1772 !isa<ExtractElementInst>(S->first))
1773 HasNontrivialInsts = true;
1775 bool FlipOrder = false;
1777 if (getDepthFactor(S->first)) {
1778 int ESContrib = CandidatePairCostSavings.find(*S)->second;
1779 DEBUG(if (DebugPairSelection) dbgs() << "\tweight {"
1780 << *S->first << " <-> " << *S->second << "} = " <<
1782 EffSize += ESContrib;
1785 // The edge weights contribute in a negative sense: they represent
1786 // the cost of shuffles.
1787 VPPIteratorPair IP = ConnectedPairDeps.equal_range(*S);
1788 if (IP.first != ConnectedPairDeps.end()) {
1789 unsigned NumDepsDirect = 0, NumDepsSwap = 0;
1790 for (std::multimap<ValuePair, ValuePair>::iterator Q = IP.first;
1791 Q != IP.second; ++Q) {
1792 if (!PrunedTree.count(Q->second))
1794 DenseMap<VPPair, unsigned>::iterator R =
1795 PairConnectionTypes.find(VPPair(Q->second, Q->first));
1796 assert(R != PairConnectionTypes.end() &&
1797 "Cannot find pair connection type");
1798 if (R->second == PairConnectionDirect)
1800 else if (R->second == PairConnectionSwap)
1804 // If there are more swaps than direct connections, then
1805 // the pair order will be flipped during fusion. So the real
1806 // number of swaps is the minimum number.
1807 FlipOrder = !FixedOrderPairs.count(*S) &&
1808 ((NumDepsSwap > NumDepsDirect) ||
1809 FixedOrderPairs.count(ValuePair(S->second, S->first)));
1811 for (std::multimap<ValuePair, ValuePair>::iterator Q = IP.first;
1812 Q != IP.second; ++Q) {
1813 if (!PrunedTree.count(Q->second))
1815 DenseMap<VPPair, unsigned>::iterator R =
1816 PairConnectionTypes.find(VPPair(Q->second, Q->first));
1817 assert(R != PairConnectionTypes.end() &&
1818 "Cannot find pair connection type");
1819 Type *Ty1 = Q->second.first->getType(),
1820 *Ty2 = Q->second.second->getType();
1821 Type *VTy = getVecTypeForPair(Ty1, Ty2);
1822 if ((R->second == PairConnectionDirect && FlipOrder) ||
1823 (R->second == PairConnectionSwap && !FlipOrder) ||
1824 R->second == PairConnectionSplat) {
1825 int ESContrib = (int) getInstrCost(Instruction::ShuffleVector,
1827 DEBUG(if (DebugPairSelection) dbgs() << "\tcost {" <<
1828 *Q->second.first << " <-> " << *Q->second.second <<
1830 *S->first << " <-> " << *S->second << "} = " <<
1832 EffSize -= ESContrib;
1837 // Compute the cost of outgoing edges. We assume that edges outgoing
1838 // to shuffles, inserts or extracts can be merged, and so contribute
1839 // no additional cost.
1840 if (!S->first->getType()->isVoidTy()) {
1841 Type *Ty1 = S->first->getType(),
1842 *Ty2 = S->second->getType();
1843 Type *VTy = getVecTypeForPair(Ty1, Ty2);
1845 bool NeedsExtraction = false;
1846 for (Value::use_iterator I = S->first->use_begin(),
1847 IE = S->first->use_end(); I != IE; ++I) {
1848 if (ShuffleVectorInst *SI = dyn_cast<ShuffleVectorInst>(*I)) {
1849 // Shuffle can be folded if it has no other input
1850 if (isa<UndefValue>(SI->getOperand(1)))
1853 if (isa<ExtractElementInst>(*I))
1855 if (PrunedTreeInstrs.count(*I))
1857 NeedsExtraction = true;
1861 if (NeedsExtraction) {
1863 if (Ty1->isVectorTy())
1864 ESContrib = (int) getInstrCost(Instruction::ShuffleVector,
1867 ESContrib = (int) TTI->getVectorInstrCost(
1868 Instruction::ExtractElement, VTy, 0);
1870 DEBUG(if (DebugPairSelection) dbgs() << "\tcost {" <<
1871 *S->first << "} = " << ESContrib << "\n");
1872 EffSize -= ESContrib;
1875 NeedsExtraction = false;
1876 for (Value::use_iterator I = S->second->use_begin(),
1877 IE = S->second->use_end(); I != IE; ++I) {
1878 if (ShuffleVectorInst *SI = dyn_cast<ShuffleVectorInst>(*I)) {
1879 // Shuffle can be folded if it has no other input
1880 if (isa<UndefValue>(SI->getOperand(1)))
1883 if (isa<ExtractElementInst>(*I))
1885 if (PrunedTreeInstrs.count(*I))
1887 NeedsExtraction = true;
1891 if (NeedsExtraction) {
1893 if (Ty2->isVectorTy())
1894 ESContrib = (int) getInstrCost(Instruction::ShuffleVector,
1897 ESContrib = (int) TTI->getVectorInstrCost(
1898 Instruction::ExtractElement, VTy, 1);
1899 DEBUG(if (DebugPairSelection) dbgs() << "\tcost {" <<
1900 *S->second << "} = " << ESContrib << "\n");
1901 EffSize -= ESContrib;
1905 // Compute the cost of incoming edges.
1906 if (!isa<LoadInst>(S->first) && !isa<StoreInst>(S->first)) {
1907 Instruction *S1 = cast<Instruction>(S->first),
1908 *S2 = cast<Instruction>(S->second);
1909 for (unsigned o = 0; o < S1->getNumOperands(); ++o) {
1910 Value *O1 = S1->getOperand(o), *O2 = S2->getOperand(o);
1912 // Combining constants into vector constants (or small vector
1913 // constants into larger ones are assumed free).
1914 if (isa<Constant>(O1) && isa<Constant>(O2))
1920 ValuePair VP = ValuePair(O1, O2);
1921 ValuePair VPR = ValuePair(O2, O1);
1923 // Internal edges are not handled here.
1924 if (PrunedTree.count(VP) || PrunedTree.count(VPR))
1927 Type *Ty1 = O1->getType(),
1928 *Ty2 = O2->getType();
1929 Type *VTy = getVecTypeForPair(Ty1, Ty2);
1931 // Combining vector operations of the same type is also assumed
1932 // folded with other operations.
1934 // If both are insert elements, then both can be widened.
1935 InsertElementInst *IEO1 = dyn_cast<InsertElementInst>(O1),
1936 *IEO2 = dyn_cast<InsertElementInst>(O2);
1937 if (IEO1 && IEO2 && isPureIEChain(IEO1) && isPureIEChain(IEO2))
1939 // If both are extract elements, and both have the same input
1940 // type, then they can be replaced with a shuffle
1941 ExtractElementInst *EIO1 = dyn_cast<ExtractElementInst>(O1),
1942 *EIO2 = dyn_cast<ExtractElementInst>(O2);
1944 EIO1->getOperand(0)->getType() ==
1945 EIO2->getOperand(0)->getType())
1947 // If both are a shuffle with equal operand types and only two
1948 // unqiue operands, then they can be replaced with a single
1950 ShuffleVectorInst *SIO1 = dyn_cast<ShuffleVectorInst>(O1),
1951 *SIO2 = dyn_cast<ShuffleVectorInst>(O2);
1953 SIO1->getOperand(0)->getType() ==
1954 SIO2->getOperand(0)->getType()) {
1955 SmallSet<Value *, 4> SIOps;
1956 SIOps.insert(SIO1->getOperand(0));
1957 SIOps.insert(SIO1->getOperand(1));
1958 SIOps.insert(SIO2->getOperand(0));
1959 SIOps.insert(SIO2->getOperand(1));
1960 if (SIOps.size() <= 2)
1966 // This pair has already been formed.
1967 if (IncomingPairs.count(VP)) {
1969 } else if (IncomingPairs.count(VPR)) {
1970 ESContrib = (int) getInstrCost(Instruction::ShuffleVector,
1972 } else if (!Ty1->isVectorTy() && !Ty2->isVectorTy()) {
1973 ESContrib = (int) TTI->getVectorInstrCost(
1974 Instruction::InsertElement, VTy, 0);
1975 ESContrib += (int) TTI->getVectorInstrCost(
1976 Instruction::InsertElement, VTy, 1);
1977 } else if (!Ty1->isVectorTy()) {
1978 // O1 needs to be inserted into a vector of size O2, and then
1979 // both need to be shuffled together.
1980 ESContrib = (int) TTI->getVectorInstrCost(
1981 Instruction::InsertElement, Ty2, 0);
1982 ESContrib += (int) getInstrCost(Instruction::ShuffleVector,
1984 } else if (!Ty2->isVectorTy()) {
1985 // O2 needs to be inserted into a vector of size O1, and then
1986 // both need to be shuffled together.
1987 ESContrib = (int) TTI->getVectorInstrCost(
1988 Instruction::InsertElement, Ty1, 0);
1989 ESContrib += (int) getInstrCost(Instruction::ShuffleVector,
1992 Type *TyBig = Ty1, *TySmall = Ty2;
1993 if (Ty2->getVectorNumElements() > Ty1->getVectorNumElements())
1994 std::swap(TyBig, TySmall);
1996 ESContrib = (int) getInstrCost(Instruction::ShuffleVector,
1998 if (TyBig != TySmall)
1999 ESContrib += (int) getInstrCost(Instruction::ShuffleVector,
2003 DEBUG(if (DebugPairSelection) dbgs() << "\tcost {"
2004 << *O1 << " <-> " << *O2 << "} = " <<
2006 EffSize -= ESContrib;
2007 IncomingPairs.insert(VP);
2012 if (!HasNontrivialInsts) {
2013 DEBUG(if (DebugPairSelection) dbgs() <<
2014 "\tNo non-trivial instructions in tree;"
2015 " override to zero effective size\n");
2019 for (DenseSet<ValuePair>::iterator S = PrunedTree.begin(),
2020 E = PrunedTree.end(); S != E; ++S)
2021 EffSize += (int) getDepthFactor(S->first);
2024 DEBUG(if (DebugPairSelection)
2025 dbgs() << "BBV: found pruned Tree for pair {"
2026 << *J->first << " <-> " << *J->second << "} of depth " <<
2027 MaxDepth << " and size " << PrunedTree.size() <<
2028 " (effective size: " << EffSize << ")\n");
2029 if (((TTI && !UseChainDepthWithTI) ||
2030 MaxDepth >= Config.ReqChainDepth) &&
2031 EffSize > 0 && EffSize > BestEffSize) {
2032 BestMaxDepth = MaxDepth;
2033 BestEffSize = EffSize;
2034 BestTree = PrunedTree;
2039 // Given the list of candidate pairs, this function selects those
2040 // that will be fused into vector instructions.
2041 void BBVectorize::choosePairs(
2042 std::multimap<Value *, Value *> &CandidatePairs,
2043 DenseMap<ValuePair, int> &CandidatePairCostSavings,
2044 std::vector<Value *> &PairableInsts,
2045 DenseSet<ValuePair> &FixedOrderPairs,
2046 DenseMap<VPPair, unsigned> &PairConnectionTypes,
2047 std::multimap<ValuePair, ValuePair> &ConnectedPairs,
2048 std::multimap<ValuePair, ValuePair> &ConnectedPairDeps,
2049 DenseSet<ValuePair> &PairableInstUsers,
2050 DenseMap<Value *, Value *>& ChosenPairs) {
2051 bool UseCycleCheck =
2052 CandidatePairs.size() <= Config.MaxCandPairsForCycleCheck;
2053 std::multimap<ValuePair, ValuePair> PairableInstUserMap;
2054 for (std::vector<Value *>::iterator I = PairableInsts.begin(),
2055 E = PairableInsts.end(); I != E; ++I) {
2056 // The number of possible pairings for this variable:
2057 size_t NumChoices = CandidatePairs.count(*I);
2058 if (!NumChoices) continue;
2060 VPIteratorPair ChoiceRange = CandidatePairs.equal_range(*I);
2062 // The best pair to choose and its tree:
2063 size_t BestMaxDepth = 0;
2064 int BestEffSize = 0;
2065 DenseSet<ValuePair> BestTree;
2066 findBestTreeFor(CandidatePairs, CandidatePairCostSavings,
2067 PairableInsts, FixedOrderPairs, PairConnectionTypes,
2068 ConnectedPairs, ConnectedPairDeps,
2069 PairableInstUsers, PairableInstUserMap, ChosenPairs,
2070 BestTree, BestMaxDepth, BestEffSize, ChoiceRange,
2073 // A tree has been chosen (or not) at this point. If no tree was
2074 // chosen, then this instruction, I, cannot be paired (and is no longer
2077 DEBUG(if (BestTree.size() > 0)
2078 dbgs() << "BBV: selected pairs in the best tree for: "
2079 << *cast<Instruction>(*I) << "\n");
2081 for (DenseSet<ValuePair>::iterator S = BestTree.begin(),
2082 SE2 = BestTree.end(); S != SE2; ++S) {
2083 // Insert the members of this tree into the list of chosen pairs.
2084 ChosenPairs.insert(ValuePair(S->first, S->second));
2085 DEBUG(dbgs() << "BBV: selected pair: " << *S->first << " <-> " <<
2086 *S->second << "\n");
2088 // Remove all candidate pairs that have values in the chosen tree.
2089 for (std::multimap<Value *, Value *>::iterator K =
2090 CandidatePairs.begin(); K != CandidatePairs.end();) {
2091 if (K->first == S->first || K->second == S->first ||
2092 K->second == S->second || K->first == S->second) {
2093 // Don't remove the actual pair chosen so that it can be used
2094 // in subsequent tree selections.
2095 if (!(K->first == S->first && K->second == S->second))
2096 CandidatePairs.erase(K++);
2106 DEBUG(dbgs() << "BBV: selected " << ChosenPairs.size() << " pairs.\n");
2109 std::string getReplacementName(Instruction *I, bool IsInput, unsigned o,
2114 return (I->getName() + (IsInput ? ".v.i" : ".v.r") + utostr(o) +
2115 (n > 0 ? "." + utostr(n) : "")).str();
2118 // Returns the value that is to be used as the pointer input to the vector
2119 // instruction that fuses I with J.
2120 Value *BBVectorize::getReplacementPointerInput(LLVMContext& Context,
2121 Instruction *I, Instruction *J, unsigned o) {
2123 unsigned IAlignment, JAlignment, IAddressSpace, JAddressSpace;
2124 int64_t OffsetInElmts;
2126 // Note: the analysis might fail here, that is why the pair order has
2127 // been precomputed (OffsetInElmts must be unused here).
2128 (void) getPairPtrInfo(I, J, IPtr, JPtr, IAlignment, JAlignment,
2129 IAddressSpace, JAddressSpace,
2130 OffsetInElmts, false);
2132 // The pointer value is taken to be the one with the lowest offset.
2135 Type *ArgTypeI = cast<PointerType>(IPtr->getType())->getElementType();
2136 Type *ArgTypeJ = cast<PointerType>(JPtr->getType())->getElementType();
2137 Type *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ);
2138 Type *VArgPtrType = PointerType::get(VArgType,
2139 cast<PointerType>(IPtr->getType())->getAddressSpace());
2140 return new BitCastInst(VPtr, VArgPtrType, getReplacementName(I, true, o),
2141 /* insert before */ I);
2144 void BBVectorize::fillNewShuffleMask(LLVMContext& Context, Instruction *J,
2145 unsigned MaskOffset, unsigned NumInElem,
2146 unsigned NumInElem1, unsigned IdxOffset,
2147 std::vector<Constant*> &Mask) {
2148 unsigned NumElem1 = cast<VectorType>(J->getType())->getNumElements();
2149 for (unsigned v = 0; v < NumElem1; ++v) {
2150 int m = cast<ShuffleVectorInst>(J)->getMaskValue(v);
2152 Mask[v+MaskOffset] = UndefValue::get(Type::getInt32Ty(Context));
2154 unsigned mm = m + (int) IdxOffset;
2155 if (m >= (int) NumInElem1)
2156 mm += (int) NumInElem;
2158 Mask[v+MaskOffset] =
2159 ConstantInt::get(Type::getInt32Ty(Context), mm);
2164 // Returns the value that is to be used as the vector-shuffle mask to the
2165 // vector instruction that fuses I with J.
2166 Value *BBVectorize::getReplacementShuffleMask(LLVMContext& Context,
2167 Instruction *I, Instruction *J) {
2168 // This is the shuffle mask. We need to append the second
2169 // mask to the first, and the numbers need to be adjusted.
2171 Type *ArgTypeI = I->getType();
2172 Type *ArgTypeJ = J->getType();
2173 Type *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ);
2175 unsigned NumElemI = cast<VectorType>(ArgTypeI)->getNumElements();
2177 // Get the total number of elements in the fused vector type.
2178 // By definition, this must equal the number of elements in
2180 unsigned NumElem = cast<VectorType>(VArgType)->getNumElements();
2181 std::vector<Constant*> Mask(NumElem);
2183 Type *OpTypeI = I->getOperand(0)->getType();
2184 unsigned NumInElemI = cast<VectorType>(OpTypeI)->getNumElements();
2185 Type *OpTypeJ = J->getOperand(0)->getType();
2186 unsigned NumInElemJ = cast<VectorType>(OpTypeJ)->getNumElements();
2188 // The fused vector will be:
2189 // -----------------------------------------------------
2190 // | NumInElemI | NumInElemJ | NumInElemI | NumInElemJ |
2191 // -----------------------------------------------------
2192 // from which we'll extract NumElem total elements (where the first NumElemI
2193 // of them come from the mask in I and the remainder come from the mask
2196 // For the mask from the first pair...
2197 fillNewShuffleMask(Context, I, 0, NumInElemJ, NumInElemI,
2200 // For the mask from the second pair...
2201 fillNewShuffleMask(Context, J, NumElemI, NumInElemI, NumInElemJ,
2204 return ConstantVector::get(Mask);
2207 bool BBVectorize::expandIEChain(LLVMContext& Context, Instruction *I,
2208 Instruction *J, unsigned o, Value *&LOp,
2210 Type *ArgTypeL, Type *ArgTypeH,
2211 bool IBeforeJ, unsigned IdxOff) {
2212 bool ExpandedIEChain = false;
2213 if (InsertElementInst *LIE = dyn_cast<InsertElementInst>(LOp)) {
2214 // If we have a pure insertelement chain, then this can be rewritten
2215 // into a chain that directly builds the larger type.
2216 if (isPureIEChain(LIE)) {
2217 SmallVector<Value *, 8> VectElemts(numElemL,
2218 UndefValue::get(ArgTypeL->getScalarType()));
2219 InsertElementInst *LIENext = LIE;
2222 cast<ConstantInt>(LIENext->getOperand(2))->getSExtValue();
2223 VectElemts[Idx] = LIENext->getOperand(1);
2225 dyn_cast<InsertElementInst>(LIENext->getOperand(0))));
2228 Value *LIEPrev = UndefValue::get(ArgTypeH);
2229 for (unsigned i = 0; i < numElemL; ++i) {
2230 if (isa<UndefValue>(VectElemts[i])) continue;
2231 LIENext = InsertElementInst::Create(LIEPrev, VectElemts[i],
2232 ConstantInt::get(Type::getInt32Ty(Context),
2234 getReplacementName(IBeforeJ ? I : J,
2236 LIENext->insertBefore(IBeforeJ ? J : I);
2240 LOp = LIENext ? (Value*) LIENext : UndefValue::get(ArgTypeH);
2241 ExpandedIEChain = true;
2245 return ExpandedIEChain;
2248 // Returns the value to be used as the specified operand of the vector
2249 // instruction that fuses I with J.
2250 Value *BBVectorize::getReplacementInput(LLVMContext& Context, Instruction *I,
2251 Instruction *J, unsigned o, bool IBeforeJ) {
2252 Value *CV0 = ConstantInt::get(Type::getInt32Ty(Context), 0);
2253 Value *CV1 = ConstantInt::get(Type::getInt32Ty(Context), 1);
2255 // Compute the fused vector type for this operand
2256 Type *ArgTypeI = I->getOperand(o)->getType();
2257 Type *ArgTypeJ = J->getOperand(o)->getType();
2258 VectorType *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ);
2260 Instruction *L = I, *H = J;
2261 Type *ArgTypeL = ArgTypeI, *ArgTypeH = ArgTypeJ;
2264 if (ArgTypeL->isVectorTy())
2265 numElemL = cast<VectorType>(ArgTypeL)->getNumElements();
2270 if (ArgTypeH->isVectorTy())
2271 numElemH = cast<VectorType>(ArgTypeH)->getNumElements();
2275 Value *LOp = L->getOperand(o);
2276 Value *HOp = H->getOperand(o);
2277 unsigned numElem = VArgType->getNumElements();
2279 // First, we check if we can reuse the "original" vector outputs (if these
2280 // exist). We might need a shuffle.
2281 ExtractElementInst *LEE = dyn_cast<ExtractElementInst>(LOp);
2282 ExtractElementInst *HEE = dyn_cast<ExtractElementInst>(HOp);
2283 ShuffleVectorInst *LSV = dyn_cast<ShuffleVectorInst>(LOp);
2284 ShuffleVectorInst *HSV = dyn_cast<ShuffleVectorInst>(HOp);
2286 // FIXME: If we're fusing shuffle instructions, then we can't apply this
2287 // optimization. The input vectors to the shuffle might be a different
2288 // length from the shuffle outputs. Unfortunately, the replacement
2289 // shuffle mask has already been formed, and the mask entries are sensitive
2290 // to the sizes of the inputs.
2291 bool IsSizeChangeShuffle =
2292 isa<ShuffleVectorInst>(L) &&
2293 (LOp->getType() != L->getType() || HOp->getType() != H->getType());
2295 if ((LEE || LSV) && (HEE || HSV) && !IsSizeChangeShuffle) {
2296 // We can have at most two unique vector inputs.
2297 bool CanUseInputs = true;
2300 I1 = LEE->getOperand(0);
2302 I1 = LSV->getOperand(0);
2303 I2 = LSV->getOperand(1);
2304 if (I2 == I1 || isa<UndefValue>(I2))
2309 Value *I3 = HEE->getOperand(0);
2310 if (!I2 && I3 != I1)
2312 else if (I3 != I1 && I3 != I2)
2313 CanUseInputs = false;
2315 Value *I3 = HSV->getOperand(0);
2316 if (!I2 && I3 != I1)
2318 else if (I3 != I1 && I3 != I2)
2319 CanUseInputs = false;
2322 Value *I4 = HSV->getOperand(1);
2323 if (!isa<UndefValue>(I4)) {
2324 if (!I2 && I4 != I1)
2326 else if (I4 != I1 && I4 != I2)
2327 CanUseInputs = false;
2334 cast<VectorType>(cast<Instruction>(LOp)->getOperand(0)->getType())
2337 cast<VectorType>(cast<Instruction>(HOp)->getOperand(0)->getType())
2340 // We have one or two input vectors. We need to map each index of the
2341 // operands to the index of the original vector.
2342 SmallVector<std::pair<int, int>, 8> II(numElem);
2343 for (unsigned i = 0; i < numElemL; ++i) {
2347 cast<ConstantInt>(LEE->getOperand(1))->getSExtValue();
2348 INum = LEE->getOperand(0) == I1 ? 0 : 1;
2350 Idx = LSV->getMaskValue(i);
2351 if (Idx < (int) LOpElem) {
2352 INum = LSV->getOperand(0) == I1 ? 0 : 1;
2355 INum = LSV->getOperand(1) == I1 ? 0 : 1;
2359 II[i] = std::pair<int, int>(Idx, INum);
2361 for (unsigned i = 0; i < numElemH; ++i) {
2365 cast<ConstantInt>(HEE->getOperand(1))->getSExtValue();
2366 INum = HEE->getOperand(0) == I1 ? 0 : 1;
2368 Idx = HSV->getMaskValue(i);
2369 if (Idx < (int) HOpElem) {
2370 INum = HSV->getOperand(0) == I1 ? 0 : 1;
2373 INum = HSV->getOperand(1) == I1 ? 0 : 1;
2377 II[i + numElemL] = std::pair<int, int>(Idx, INum);
2380 // We now have an array which tells us from which index of which
2381 // input vector each element of the operand comes.
2382 VectorType *I1T = cast<VectorType>(I1->getType());
2383 unsigned I1Elem = I1T->getNumElements();
2386 // In this case there is only one underlying vector input. Check for
2387 // the trivial case where we can use the input directly.
2388 if (I1Elem == numElem) {
2389 bool ElemInOrder = true;
2390 for (unsigned i = 0; i < numElem; ++i) {
2391 if (II[i].first != (int) i && II[i].first != -1) {
2392 ElemInOrder = false;
2401 // A shuffle is needed.
2402 std::vector<Constant *> Mask(numElem);
2403 for (unsigned i = 0; i < numElem; ++i) {
2404 int Idx = II[i].first;
2406 Mask[i] = UndefValue::get(Type::getInt32Ty(Context));
2408 Mask[i] = ConstantInt::get(Type::getInt32Ty(Context), Idx);
2412 new ShuffleVectorInst(I1, UndefValue::get(I1T),
2413 ConstantVector::get(Mask),
2414 getReplacementName(IBeforeJ ? I : J,
2416 S->insertBefore(IBeforeJ ? J : I);
2420 VectorType *I2T = cast<VectorType>(I2->getType());
2421 unsigned I2Elem = I2T->getNumElements();
2423 // This input comes from two distinct vectors. The first step is to
2424 // make sure that both vectors are the same length. If not, the
2425 // smaller one will need to grow before they can be shuffled together.
2426 if (I1Elem < I2Elem) {
2427 std::vector<Constant *> Mask(I2Elem);
2429 for (; v < I1Elem; ++v)
2430 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v);
2431 for (; v < I2Elem; ++v)
2432 Mask[v] = UndefValue::get(Type::getInt32Ty(Context));
2434 Instruction *NewI1 =
2435 new ShuffleVectorInst(I1, UndefValue::get(I1T),
2436 ConstantVector::get(Mask),
2437 getReplacementName(IBeforeJ ? I : J,
2439 NewI1->insertBefore(IBeforeJ ? J : I);
2443 } else if (I1Elem > I2Elem) {
2444 std::vector<Constant *> Mask(I1Elem);
2446 for (; v < I2Elem; ++v)
2447 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v);
2448 for (; v < I1Elem; ++v)
2449 Mask[v] = UndefValue::get(Type::getInt32Ty(Context));
2451 Instruction *NewI2 =
2452 new ShuffleVectorInst(I2, UndefValue::get(I2T),
2453 ConstantVector::get(Mask),
2454 getReplacementName(IBeforeJ ? I : J,
2456 NewI2->insertBefore(IBeforeJ ? J : I);
2462 // Now that both I1 and I2 are the same length we can shuffle them
2463 // together (and use the result).
2464 std::vector<Constant *> Mask(numElem);
2465 for (unsigned v = 0; v < numElem; ++v) {
2466 if (II[v].first == -1) {
2467 Mask[v] = UndefValue::get(Type::getInt32Ty(Context));
2469 int Idx = II[v].first + II[v].second * I1Elem;
2470 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), Idx);
2474 Instruction *NewOp =
2475 new ShuffleVectorInst(I1, I2, ConstantVector::get(Mask),
2476 getReplacementName(IBeforeJ ? I : J, true, o));
2477 NewOp->insertBefore(IBeforeJ ? J : I);
2482 Type *ArgType = ArgTypeL;
2483 if (numElemL < numElemH) {
2484 if (numElemL == 1 && expandIEChain(Context, I, J, o, HOp, numElemH,
2485 ArgTypeL, VArgType, IBeforeJ, 1)) {
2486 // This is another short-circuit case: we're combining a scalar into
2487 // a vector that is formed by an IE chain. We've just expanded the IE
2488 // chain, now insert the scalar and we're done.
2490 Instruction *S = InsertElementInst::Create(HOp, LOp, CV0,
2491 getReplacementName(IBeforeJ ? I : J, true, o));
2492 S->insertBefore(IBeforeJ ? J : I);
2494 } else if (!expandIEChain(Context, I, J, o, LOp, numElemL, ArgTypeL,
2495 ArgTypeH, IBeforeJ)) {
2496 // The two vector inputs to the shuffle must be the same length,
2497 // so extend the smaller vector to be the same length as the larger one.
2501 std::vector<Constant *> Mask(numElemH);
2503 for (; v < numElemL; ++v)
2504 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v);
2505 for (; v < numElemH; ++v)
2506 Mask[v] = UndefValue::get(Type::getInt32Ty(Context));
2508 NLOp = new ShuffleVectorInst(LOp, UndefValue::get(ArgTypeL),
2509 ConstantVector::get(Mask),
2510 getReplacementName(IBeforeJ ? I : J,
2513 NLOp = InsertElementInst::Create(UndefValue::get(ArgTypeH), LOp, CV0,
2514 getReplacementName(IBeforeJ ? I : J,
2518 NLOp->insertBefore(IBeforeJ ? J : I);
2523 } else if (numElemL > numElemH) {
2524 if (numElemH == 1 && expandIEChain(Context, I, J, o, LOp, numElemL,
2525 ArgTypeH, VArgType, IBeforeJ)) {
2527 InsertElementInst::Create(LOp, HOp,
2528 ConstantInt::get(Type::getInt32Ty(Context),
2530 getReplacementName(IBeforeJ ? I : J,
2532 S->insertBefore(IBeforeJ ? J : I);
2534 } else if (!expandIEChain(Context, I, J, o, HOp, numElemH, ArgTypeH,
2535 ArgTypeL, IBeforeJ)) {
2538 std::vector<Constant *> Mask(numElemL);
2540 for (; v < numElemH; ++v)
2541 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v);
2542 for (; v < numElemL; ++v)
2543 Mask[v] = UndefValue::get(Type::getInt32Ty(Context));
2545 NHOp = new ShuffleVectorInst(HOp, UndefValue::get(ArgTypeH),
2546 ConstantVector::get(Mask),
2547 getReplacementName(IBeforeJ ? I : J,
2550 NHOp = InsertElementInst::Create(UndefValue::get(ArgTypeL), HOp, CV0,
2551 getReplacementName(IBeforeJ ? I : J,
2555 NHOp->insertBefore(IBeforeJ ? J : I);
2560 if (ArgType->isVectorTy()) {
2561 unsigned numElem = cast<VectorType>(VArgType)->getNumElements();
2562 std::vector<Constant*> Mask(numElem);
2563 for (unsigned v = 0; v < numElem; ++v) {
2565 // If the low vector was expanded, we need to skip the extra
2566 // undefined entries.
2567 if (v >= numElemL && numElemH > numElemL)
2568 Idx += (numElemH - numElemL);
2569 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), Idx);
2572 Instruction *BV = new ShuffleVectorInst(LOp, HOp,
2573 ConstantVector::get(Mask),
2574 getReplacementName(IBeforeJ ? I : J, true, o));
2575 BV->insertBefore(IBeforeJ ? J : I);
2579 Instruction *BV1 = InsertElementInst::Create(
2580 UndefValue::get(VArgType), LOp, CV0,
2581 getReplacementName(IBeforeJ ? I : J,
2583 BV1->insertBefore(IBeforeJ ? J : I);
2584 Instruction *BV2 = InsertElementInst::Create(BV1, HOp, CV1,
2585 getReplacementName(IBeforeJ ? I : J,
2587 BV2->insertBefore(IBeforeJ ? J : I);
2591 // This function creates an array of values that will be used as the inputs
2592 // to the vector instruction that fuses I with J.
2593 void BBVectorize::getReplacementInputsForPair(LLVMContext& Context,
2594 Instruction *I, Instruction *J,
2595 SmallVector<Value *, 3> &ReplacedOperands,
2597 unsigned NumOperands = I->getNumOperands();
2599 for (unsigned p = 0, o = NumOperands-1; p < NumOperands; ++p, --o) {
2600 // Iterate backward so that we look at the store pointer
2601 // first and know whether or not we need to flip the inputs.
2603 if (isa<LoadInst>(I) || (o == 1 && isa<StoreInst>(I))) {
2604 // This is the pointer for a load/store instruction.
2605 ReplacedOperands[o] = getReplacementPointerInput(Context, I, J, o);
2607 } else if (isa<CallInst>(I)) {
2608 Function *F = cast<CallInst>(I)->getCalledFunction();
2609 Intrinsic::ID IID = (Intrinsic::ID) F->getIntrinsicID();
2610 if (o == NumOperands-1) {
2611 BasicBlock &BB = *I->getParent();
2613 Module *M = BB.getParent()->getParent();
2614 Type *ArgTypeI = I->getType();
2615 Type *ArgTypeJ = J->getType();
2616 Type *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ);
2618 ReplacedOperands[o] = Intrinsic::getDeclaration(M, IID, VArgType);
2620 } else if (IID == Intrinsic::powi && o == 1) {
2621 // The second argument of powi is a single integer and we've already
2622 // checked that both arguments are equal. As a result, we just keep
2623 // I's second argument.
2624 ReplacedOperands[o] = I->getOperand(o);
2627 } else if (isa<ShuffleVectorInst>(I) && o == NumOperands-1) {
2628 ReplacedOperands[o] = getReplacementShuffleMask(Context, I, J);
2632 ReplacedOperands[o] = getReplacementInput(Context, I, J, o, IBeforeJ);
2636 // This function creates two values that represent the outputs of the
2637 // original I and J instructions. These are generally vector shuffles
2638 // or extracts. In many cases, these will end up being unused and, thus,
2639 // eliminated by later passes.
2640 void BBVectorize::replaceOutputsOfPair(LLVMContext& Context, Instruction *I,
2641 Instruction *J, Instruction *K,
2642 Instruction *&InsertionPt,
2643 Instruction *&K1, Instruction *&K2) {
2644 if (isa<StoreInst>(I)) {
2645 AA->replaceWithNewValue(I, K);
2646 AA->replaceWithNewValue(J, K);
2648 Type *IType = I->getType();
2649 Type *JType = J->getType();
2651 VectorType *VType = getVecTypeForPair(IType, JType);
2652 unsigned numElem = VType->getNumElements();
2654 unsigned numElemI, numElemJ;
2655 if (IType->isVectorTy())
2656 numElemI = cast<VectorType>(IType)->getNumElements();
2660 if (JType->isVectorTy())
2661 numElemJ = cast<VectorType>(JType)->getNumElements();
2665 if (IType->isVectorTy()) {
2666 std::vector<Constant*> Mask1(numElemI), Mask2(numElemI);
2667 for (unsigned v = 0; v < numElemI; ++v) {
2668 Mask1[v] = ConstantInt::get(Type::getInt32Ty(Context), v);
2669 Mask2[v] = ConstantInt::get(Type::getInt32Ty(Context), numElemJ+v);
2672 K1 = new ShuffleVectorInst(K, UndefValue::get(VType),
2673 ConstantVector::get( Mask1),
2674 getReplacementName(K, false, 1));
2676 Value *CV0 = ConstantInt::get(Type::getInt32Ty(Context), 0);
2677 K1 = ExtractElementInst::Create(K, CV0,
2678 getReplacementName(K, false, 1));
2681 if (JType->isVectorTy()) {
2682 std::vector<Constant*> Mask1(numElemJ), Mask2(numElemJ);
2683 for (unsigned v = 0; v < numElemJ; ++v) {
2684 Mask1[v] = ConstantInt::get(Type::getInt32Ty(Context), v);
2685 Mask2[v] = ConstantInt::get(Type::getInt32Ty(Context), numElemI+v);
2688 K2 = new ShuffleVectorInst(K, UndefValue::get(VType),
2689 ConstantVector::get( Mask2),
2690 getReplacementName(K, false, 2));
2692 Value *CV1 = ConstantInt::get(Type::getInt32Ty(Context), numElem-1);
2693 K2 = ExtractElementInst::Create(K, CV1,
2694 getReplacementName(K, false, 2));
2698 K2->insertAfter(K1);
2703 // Move all uses of the function I (including pairing-induced uses) after J.
2704 bool BBVectorize::canMoveUsesOfIAfterJ(BasicBlock &BB,
2705 std::multimap<Value *, Value *> &LoadMoveSet,
2706 Instruction *I, Instruction *J) {
2707 // Skip to the first instruction past I.
2708 BasicBlock::iterator L = llvm::next(BasicBlock::iterator(I));
2710 DenseSet<Value *> Users;
2711 AliasSetTracker WriteSet(*AA);
2712 for (; cast<Instruction>(L) != J; ++L)
2713 (void) trackUsesOfI(Users, WriteSet, I, L, true, &LoadMoveSet);
2715 assert(cast<Instruction>(L) == J &&
2716 "Tracking has not proceeded far enough to check for dependencies");
2717 // If J is now in the use set of I, then trackUsesOfI will return true
2718 // and we have a dependency cycle (and the fusing operation must abort).
2719 return !trackUsesOfI(Users, WriteSet, I, J, true, &LoadMoveSet);
2722 // Move all uses of the function I (including pairing-induced uses) after J.
2723 void BBVectorize::moveUsesOfIAfterJ(BasicBlock &BB,
2724 std::multimap<Value *, Value *> &LoadMoveSet,
2725 Instruction *&InsertionPt,
2726 Instruction *I, Instruction *J) {
2727 // Skip to the first instruction past I.
2728 BasicBlock::iterator L = llvm::next(BasicBlock::iterator(I));
2730 DenseSet<Value *> Users;
2731 AliasSetTracker WriteSet(*AA);
2732 for (; cast<Instruction>(L) != J;) {
2733 if (trackUsesOfI(Users, WriteSet, I, L, true, &LoadMoveSet)) {
2734 // Move this instruction
2735 Instruction *InstToMove = L; ++L;
2737 DEBUG(dbgs() << "BBV: moving: " << *InstToMove <<
2738 " to after " << *InsertionPt << "\n");
2739 InstToMove->removeFromParent();
2740 InstToMove->insertAfter(InsertionPt);
2741 InsertionPt = InstToMove;
2748 // Collect all load instruction that are in the move set of a given first
2749 // pair member. These loads depend on the first instruction, I, and so need
2750 // to be moved after J (the second instruction) when the pair is fused.
2751 void BBVectorize::collectPairLoadMoveSet(BasicBlock &BB,
2752 DenseMap<Value *, Value *> &ChosenPairs,
2753 std::multimap<Value *, Value *> &LoadMoveSet,
2755 // Skip to the first instruction past I.
2756 BasicBlock::iterator L = llvm::next(BasicBlock::iterator(I));
2758 DenseSet<Value *> Users;
2759 AliasSetTracker WriteSet(*AA);
2761 // Note: We cannot end the loop when we reach J because J could be moved
2762 // farther down the use chain by another instruction pairing. Also, J
2763 // could be before I if this is an inverted input.
2764 for (BasicBlock::iterator E = BB.end(); cast<Instruction>(L) != E; ++L) {
2765 if (trackUsesOfI(Users, WriteSet, I, L)) {
2766 if (L->mayReadFromMemory())
2767 LoadMoveSet.insert(ValuePair(L, I));
2772 // In cases where both load/stores and the computation of their pointers
2773 // are chosen for vectorization, we can end up in a situation where the
2774 // aliasing analysis starts returning different query results as the
2775 // process of fusing instruction pairs continues. Because the algorithm
2776 // relies on finding the same use trees here as were found earlier, we'll
2777 // need to precompute the necessary aliasing information here and then
2778 // manually update it during the fusion process.
2779 void BBVectorize::collectLoadMoveSet(BasicBlock &BB,
2780 std::vector<Value *> &PairableInsts,
2781 DenseMap<Value *, Value *> &ChosenPairs,
2782 std::multimap<Value *, Value *> &LoadMoveSet) {
2783 for (std::vector<Value *>::iterator PI = PairableInsts.begin(),
2784 PIE = PairableInsts.end(); PI != PIE; ++PI) {
2785 DenseMap<Value *, Value *>::iterator P = ChosenPairs.find(*PI);
2786 if (P == ChosenPairs.end()) continue;
2788 Instruction *I = cast<Instruction>(P->first);
2789 collectPairLoadMoveSet(BB, ChosenPairs, LoadMoveSet, I);
2793 // When the first instruction in each pair is cloned, it will inherit its
2794 // parent's metadata. This metadata must be combined with that of the other
2795 // instruction in a safe way.
2796 void BBVectorize::combineMetadata(Instruction *K, const Instruction *J) {
2797 SmallVector<std::pair<unsigned, MDNode*>, 4> Metadata;
2798 K->getAllMetadataOtherThanDebugLoc(Metadata);
2799 for (unsigned i = 0, n = Metadata.size(); i < n; ++i) {
2800 unsigned Kind = Metadata[i].first;
2801 MDNode *JMD = J->getMetadata(Kind);
2802 MDNode *KMD = Metadata[i].second;
2806 K->setMetadata(Kind, 0); // Remove unknown metadata
2808 case LLVMContext::MD_tbaa:
2809 K->setMetadata(Kind, MDNode::getMostGenericTBAA(JMD, KMD));
2811 case LLVMContext::MD_fpmath:
2812 K->setMetadata(Kind, MDNode::getMostGenericFPMath(JMD, KMD));
2818 // This function fuses the chosen instruction pairs into vector instructions,
2819 // taking care preserve any needed scalar outputs and, then, it reorders the
2820 // remaining instructions as needed (users of the first member of the pair
2821 // need to be moved to after the location of the second member of the pair
2822 // because the vector instruction is inserted in the location of the pair's
2824 void BBVectorize::fuseChosenPairs(BasicBlock &BB,
2825 std::vector<Value *> &PairableInsts,
2826 DenseMap<Value *, Value *> &ChosenPairs,
2827 DenseSet<ValuePair> &FixedOrderPairs,
2828 DenseMap<VPPair, unsigned> &PairConnectionTypes,
2829 std::multimap<ValuePair, ValuePair> &ConnectedPairs,
2830 std::multimap<ValuePair, ValuePair> &ConnectedPairDeps) {
2831 LLVMContext& Context = BB.getContext();
2833 // During the vectorization process, the order of the pairs to be fused
2834 // could be flipped. So we'll add each pair, flipped, into the ChosenPairs
2835 // list. After a pair is fused, the flipped pair is removed from the list.
2836 DenseSet<ValuePair> FlippedPairs;
2837 for (DenseMap<Value *, Value *>::iterator P = ChosenPairs.begin(),
2838 E = ChosenPairs.end(); P != E; ++P)
2839 FlippedPairs.insert(ValuePair(P->second, P->first));
2840 for (DenseSet<ValuePair>::iterator P = FlippedPairs.begin(),
2841 E = FlippedPairs.end(); P != E; ++P)
2842 ChosenPairs.insert(*P);
2844 std::multimap<Value *, Value *> LoadMoveSet;
2845 collectLoadMoveSet(BB, PairableInsts, ChosenPairs, LoadMoveSet);
2847 DEBUG(dbgs() << "BBV: initial: \n" << BB << "\n");
2849 for (BasicBlock::iterator PI = BB.getFirstInsertionPt(); PI != BB.end();) {
2850 DenseMap<Value *, Value *>::iterator P = ChosenPairs.find(PI);
2851 if (P == ChosenPairs.end()) {
2856 if (getDepthFactor(P->first) == 0) {
2857 // These instructions are not really fused, but are tracked as though
2858 // they are. Any case in which it would be interesting to fuse them
2859 // will be taken care of by InstCombine.
2865 Instruction *I = cast<Instruction>(P->first),
2866 *J = cast<Instruction>(P->second);
2868 DEBUG(dbgs() << "BBV: fusing: " << *I <<
2869 " <-> " << *J << "\n");
2871 // Remove the pair and flipped pair from the list.
2872 DenseMap<Value *, Value *>::iterator FP = ChosenPairs.find(P->second);
2873 assert(FP != ChosenPairs.end() && "Flipped pair not found in list");
2874 ChosenPairs.erase(FP);
2875 ChosenPairs.erase(P);
2877 if (!canMoveUsesOfIAfterJ(BB, LoadMoveSet, I, J)) {
2878 DEBUG(dbgs() << "BBV: fusion of: " << *I <<
2880 " aborted because of non-trivial dependency cycle\n");
2886 // If the pair must have the other order, then flip it.
2887 bool FlipPairOrder = FixedOrderPairs.count(ValuePair(J, I));
2888 if (!FlipPairOrder && !FixedOrderPairs.count(ValuePair(I, J))) {
2889 // This pair does not have a fixed order, and so we might want to
2890 // flip it if that will yield fewer shuffles. We count the number
2891 // of dependencies connected via swaps, and those directly connected,
2892 // and flip the order if the number of swaps is greater.
2893 bool OrigOrder = true;
2894 VPPIteratorPair IP = ConnectedPairDeps.equal_range(ValuePair(I, J));
2895 if (IP.first == ConnectedPairDeps.end()) {
2896 IP = ConnectedPairDeps.equal_range(ValuePair(J, I));
2900 if (IP.first != ConnectedPairDeps.end()) {
2901 unsigned NumDepsDirect = 0, NumDepsSwap = 0;
2902 for (std::multimap<ValuePair, ValuePair>::iterator Q = IP.first;
2903 Q != IP.second; ++Q) {
2904 DenseMap<VPPair, unsigned>::iterator R =
2905 PairConnectionTypes.find(VPPair(Q->second, Q->first));
2906 assert(R != PairConnectionTypes.end() &&
2907 "Cannot find pair connection type");
2908 if (R->second == PairConnectionDirect)
2910 else if (R->second == PairConnectionSwap)
2915 std::swap(NumDepsDirect, NumDepsSwap);
2917 if (NumDepsSwap > NumDepsDirect) {
2918 FlipPairOrder = true;
2919 DEBUG(dbgs() << "BBV: reordering pair: " << *I <<
2920 " <-> " << *J << "\n");
2925 Instruction *L = I, *H = J;
2929 // If the pair being fused uses the opposite order from that in the pair
2930 // connection map, then we need to flip the types.
2931 VPPIteratorPair IP = ConnectedPairs.equal_range(ValuePair(H, L));
2932 for (std::multimap<ValuePair, ValuePair>::iterator Q = IP.first;
2933 Q != IP.second; ++Q) {
2934 DenseMap<VPPair, unsigned>::iterator R = PairConnectionTypes.find(*Q);
2935 assert(R != PairConnectionTypes.end() &&
2936 "Cannot find pair connection type");
2937 if (R->second == PairConnectionDirect)
2938 R->second = PairConnectionSwap;
2939 else if (R->second == PairConnectionSwap)
2940 R->second = PairConnectionDirect;
2943 bool LBeforeH = !FlipPairOrder;
2944 unsigned NumOperands = I->getNumOperands();
2945 SmallVector<Value *, 3> ReplacedOperands(NumOperands);
2946 getReplacementInputsForPair(Context, L, H, ReplacedOperands,
2949 // Make a copy of the original operation, change its type to the vector
2950 // type and replace its operands with the vector operands.
2951 Instruction *K = L->clone();
2954 else if (H->hasName())
2957 if (!isa<StoreInst>(K))
2958 K->mutateType(getVecTypeForPair(L->getType(), H->getType()));
2960 combineMetadata(K, H);
2961 K->intersectOptionalDataWith(H);
2963 for (unsigned o = 0; o < NumOperands; ++o)
2964 K->setOperand(o, ReplacedOperands[o]);
2968 // Instruction insertion point:
2969 Instruction *InsertionPt = K;
2970 Instruction *K1 = 0, *K2 = 0;
2971 replaceOutputsOfPair(Context, L, H, K, InsertionPt, K1, K2);
2973 // The use tree of the first original instruction must be moved to after
2974 // the location of the second instruction. The entire use tree of the
2975 // first instruction is disjoint from the input tree of the second
2976 // (by definition), and so commutes with it.
2978 moveUsesOfIAfterJ(BB, LoadMoveSet, InsertionPt, I, J);
2980 if (!isa<StoreInst>(I)) {
2981 L->replaceAllUsesWith(K1);
2982 H->replaceAllUsesWith(K2);
2983 AA->replaceWithNewValue(L, K1);
2984 AA->replaceWithNewValue(H, K2);
2987 // Instructions that may read from memory may be in the load move set.
2988 // Once an instruction is fused, we no longer need its move set, and so
2989 // the values of the map never need to be updated. However, when a load
2990 // is fused, we need to merge the entries from both instructions in the
2991 // pair in case those instructions were in the move set of some other
2992 // yet-to-be-fused pair. The loads in question are the keys of the map.
2993 if (I->mayReadFromMemory()) {
2994 std::vector<ValuePair> NewSetMembers;
2995 VPIteratorPair IPairRange = LoadMoveSet.equal_range(I);
2996 VPIteratorPair JPairRange = LoadMoveSet.equal_range(J);
2997 for (std::multimap<Value *, Value *>::iterator N = IPairRange.first;
2998 N != IPairRange.second; ++N)
2999 NewSetMembers.push_back(ValuePair(K, N->second));
3000 for (std::multimap<Value *, Value *>::iterator N = JPairRange.first;
3001 N != JPairRange.second; ++N)
3002 NewSetMembers.push_back(ValuePair(K, N->second));
3003 for (std::vector<ValuePair>::iterator A = NewSetMembers.begin(),
3004 AE = NewSetMembers.end(); A != AE; ++A)
3005 LoadMoveSet.insert(*A);
3008 // Before removing I, set the iterator to the next instruction.
3009 PI = llvm::next(BasicBlock::iterator(I));
3010 if (cast<Instruction>(PI) == J)
3015 I->eraseFromParent();
3016 J->eraseFromParent();
3018 DEBUG(if (PrintAfterEveryPair) dbgs() << "BBV: block is now: \n" <<
3022 DEBUG(dbgs() << "BBV: final: \n" << BB << "\n");
3026 char BBVectorize::ID = 0;
3027 static const char bb_vectorize_name[] = "Basic-Block Vectorization";
3028 INITIALIZE_PASS_BEGIN(BBVectorize, BBV_NAME, bb_vectorize_name, false, false)
3029 INITIALIZE_AG_DEPENDENCY(AliasAnalysis)
3030 INITIALIZE_AG_DEPENDENCY(TargetTransformInfo)
3031 INITIALIZE_PASS_DEPENDENCY(DominatorTree)
3032 INITIALIZE_PASS_DEPENDENCY(ScalarEvolution)
3033 INITIALIZE_PASS_END(BBVectorize, BBV_NAME, bb_vectorize_name, false, false)
3035 BasicBlockPass *llvm::createBBVectorizePass(const VectorizeConfig &C) {
3036 return new BBVectorize(C);
3040 llvm::vectorizeBasicBlock(Pass *P, BasicBlock &BB, const VectorizeConfig &C) {
3041 BBVectorize BBVectorizer(P, C);
3042 return BBVectorizer.vectorizeBB(BB);
3045 //===----------------------------------------------------------------------===//
3046 VectorizeConfig::VectorizeConfig() {
3047 VectorBits = ::VectorBits;
3048 VectorizeBools = !::NoBools;
3049 VectorizeInts = !::NoInts;
3050 VectorizeFloats = !::NoFloats;
3051 VectorizePointers = !::NoPointers;
3052 VectorizeCasts = !::NoCasts;
3053 VectorizeMath = !::NoMath;
3054 VectorizeFMA = !::NoFMA;
3055 VectorizeSelect = !::NoSelect;
3056 VectorizeCmp = !::NoCmp;
3057 VectorizeGEP = !::NoGEP;
3058 VectorizeMemOps = !::NoMemOps;
3059 AlignedOnly = ::AlignedOnly;
3060 ReqChainDepth= ::ReqChainDepth;
3061 SearchLimit = ::SearchLimit;
3062 MaxCandPairsForCycleCheck = ::MaxCandPairsForCycleCheck;
3063 SplatBreaksChain = ::SplatBreaksChain;
3064 MaxInsts = ::MaxInsts;
3065 MaxIter = ::MaxIter;
3066 Pow2LenOnly = ::Pow2LenOnly;
3067 NoMemOpBoost = ::NoMemOpBoost;
3068 FastDep = ::FastDep;