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/Constants.h"
20 #include "llvm/DerivedTypes.h"
21 #include "llvm/Function.h"
22 #include "llvm/Instructions.h"
23 #include "llvm/IntrinsicInst.h"
24 #include "llvm/Intrinsics.h"
25 #include "llvm/LLVMContext.h"
26 #include "llvm/Metadata.h"
27 #include "llvm/Pass.h"
28 #include "llvm/Type.h"
29 #include "llvm/ADT/DenseMap.h"
30 #include "llvm/ADT/DenseSet.h"
31 #include "llvm/ADT/SmallSet.h"
32 #include "llvm/ADT/SmallVector.h"
33 #include "llvm/ADT/Statistic.h"
34 #include "llvm/ADT/STLExtras.h"
35 #include "llvm/ADT/StringExtras.h"
36 #include "llvm/Analysis/AliasAnalysis.h"
37 #include "llvm/Analysis/AliasSetTracker.h"
38 #include "llvm/Analysis/Dominators.h"
39 #include "llvm/Analysis/ScalarEvolution.h"
40 #include "llvm/Analysis/ScalarEvolutionExpressions.h"
41 #include "llvm/Analysis/ValueTracking.h"
42 #include "llvm/Support/CommandLine.h"
43 #include "llvm/Support/Debug.h"
44 #include "llvm/Support/raw_ostream.h"
45 #include "llvm/Support/ValueHandle.h"
46 #include "llvm/DataLayout.h"
47 #include "llvm/TargetTransformInfo.h"
48 #include "llvm/Transforms/Utils/Local.h"
49 #include "llvm/Transforms/Vectorize.h"
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 :
203 P->getAnalysisIfAvailable<TargetTransformInfo>();
204 VTTI = TTI ? TTI->getVectorTargetTransformInfo() : 0;
207 typedef std::pair<Value *, Value *> ValuePair;
208 typedef std::pair<ValuePair, int> ValuePairWithCost;
209 typedef std::pair<ValuePair, size_t> ValuePairWithDepth;
210 typedef std::pair<ValuePair, ValuePair> VPPair; // A ValuePair pair
211 typedef std::pair<VPPair, unsigned> VPPairWithType;
212 typedef std::pair<std::multimap<Value *, Value *>::iterator,
213 std::multimap<Value *, Value *>::iterator> VPIteratorPair;
214 typedef std::pair<std::multimap<ValuePair, ValuePair>::iterator,
215 std::multimap<ValuePair, ValuePair>::iterator>
222 TargetTransformInfo *TTI;
223 const VectorTargetTransformInfo *VTTI;
225 // FIXME: const correct?
227 bool vectorizePairs(BasicBlock &BB, bool NonPow2Len = false);
229 bool getCandidatePairs(BasicBlock &BB,
230 BasicBlock::iterator &Start,
231 std::multimap<Value *, Value *> &CandidatePairs,
232 DenseSet<ValuePair> &FixedOrderPairs,
233 DenseMap<ValuePair, int> &CandidatePairCostSavings,
234 std::vector<Value *> &PairableInsts, bool NonPow2Len);
236 // FIXME: The current implementation does not account for pairs that
237 // are connected in multiple ways. For example:
238 // C1 = A1 / A2; C2 = A2 / A1 (which may be both direct and a swap)
239 enum PairConnectionType {
240 PairConnectionDirect,
245 void computeConnectedPairs(std::multimap<Value *, Value *> &CandidatePairs,
246 std::vector<Value *> &PairableInsts,
247 std::multimap<ValuePair, ValuePair> &ConnectedPairs,
248 DenseMap<VPPair, unsigned> &PairConnectionTypes);
250 void buildDepMap(BasicBlock &BB,
251 std::multimap<Value *, Value *> &CandidatePairs,
252 std::vector<Value *> &PairableInsts,
253 DenseSet<ValuePair> &PairableInstUsers);
255 void choosePairs(std::multimap<Value *, Value *> &CandidatePairs,
256 DenseMap<ValuePair, int> &CandidatePairCostSavings,
257 std::vector<Value *> &PairableInsts,
258 DenseSet<ValuePair> &FixedOrderPairs,
259 DenseMap<VPPair, unsigned> &PairConnectionTypes,
260 std::multimap<ValuePair, ValuePair> &ConnectedPairs,
261 std::multimap<ValuePair, ValuePair> &ConnectedPairDeps,
262 DenseSet<ValuePair> &PairableInstUsers,
263 DenseMap<Value *, Value *>& ChosenPairs);
265 void fuseChosenPairs(BasicBlock &BB,
266 std::vector<Value *> &PairableInsts,
267 DenseMap<Value *, Value *>& ChosenPairs,
268 DenseSet<ValuePair> &FixedOrderPairs,
269 DenseMap<VPPair, unsigned> &PairConnectionTypes,
270 std::multimap<ValuePair, ValuePair> &ConnectedPairs,
271 std::multimap<ValuePair, ValuePair> &ConnectedPairDeps);
274 bool isInstVectorizable(Instruction *I, bool &IsSimpleLoadStore);
276 bool areInstsCompatible(Instruction *I, Instruction *J,
277 bool IsSimpleLoadStore, bool NonPow2Len,
278 int &CostSavings, int &FixedOrder);
280 bool trackUsesOfI(DenseSet<Value *> &Users,
281 AliasSetTracker &WriteSet, Instruction *I,
282 Instruction *J, bool UpdateUsers = true,
283 std::multimap<Value *, Value *> *LoadMoveSet = 0);
285 void computePairsConnectedTo(
286 std::multimap<Value *, Value *> &CandidatePairs,
287 std::vector<Value *> &PairableInsts,
288 std::multimap<ValuePair, ValuePair> &ConnectedPairs,
289 DenseMap<VPPair, unsigned> &PairConnectionTypes,
292 bool pairsConflict(ValuePair P, ValuePair Q,
293 DenseSet<ValuePair> &PairableInstUsers,
294 std::multimap<ValuePair, ValuePair> *PairableInstUserMap = 0);
296 bool pairWillFormCycle(ValuePair P,
297 std::multimap<ValuePair, ValuePair> &PairableInstUsers,
298 DenseSet<ValuePair> &CurrentPairs);
301 std::multimap<Value *, Value *> &CandidatePairs,
302 std::vector<Value *> &PairableInsts,
303 std::multimap<ValuePair, ValuePair> &ConnectedPairs,
304 DenseSet<ValuePair> &PairableInstUsers,
305 std::multimap<ValuePair, ValuePair> &PairableInstUserMap,
306 DenseMap<Value *, Value *> &ChosenPairs,
307 DenseMap<ValuePair, size_t> &Tree,
308 DenseSet<ValuePair> &PrunedTree, ValuePair J,
311 void buildInitialTreeFor(
312 std::multimap<Value *, Value *> &CandidatePairs,
313 std::vector<Value *> &PairableInsts,
314 std::multimap<ValuePair, ValuePair> &ConnectedPairs,
315 DenseSet<ValuePair> &PairableInstUsers,
316 DenseMap<Value *, Value *> &ChosenPairs,
317 DenseMap<ValuePair, size_t> &Tree, ValuePair J);
319 void findBestTreeFor(
320 std::multimap<Value *, Value *> &CandidatePairs,
321 DenseMap<ValuePair, int> &CandidatePairCostSavings,
322 std::vector<Value *> &PairableInsts,
323 DenseSet<ValuePair> &FixedOrderPairs,
324 DenseMap<VPPair, unsigned> &PairConnectionTypes,
325 std::multimap<ValuePair, ValuePair> &ConnectedPairs,
326 std::multimap<ValuePair, ValuePair> &ConnectedPairDeps,
327 DenseSet<ValuePair> &PairableInstUsers,
328 std::multimap<ValuePair, ValuePair> &PairableInstUserMap,
329 DenseMap<Value *, Value *> &ChosenPairs,
330 DenseSet<ValuePair> &BestTree, size_t &BestMaxDepth,
331 int &BestEffSize, VPIteratorPair ChoiceRange,
334 Value *getReplacementPointerInput(LLVMContext& Context, Instruction *I,
335 Instruction *J, unsigned o);
337 void fillNewShuffleMask(LLVMContext& Context, Instruction *J,
338 unsigned MaskOffset, unsigned NumInElem,
339 unsigned NumInElem1, unsigned IdxOffset,
340 std::vector<Constant*> &Mask);
342 Value *getReplacementShuffleMask(LLVMContext& Context, Instruction *I,
345 bool expandIEChain(LLVMContext& Context, Instruction *I, Instruction *J,
346 unsigned o, Value *&LOp, unsigned numElemL,
347 Type *ArgTypeL, Type *ArgTypeR, bool IBeforeJ,
348 unsigned IdxOff = 0);
350 Value *getReplacementInput(LLVMContext& Context, Instruction *I,
351 Instruction *J, unsigned o, bool IBeforeJ);
353 void getReplacementInputsForPair(LLVMContext& Context, Instruction *I,
354 Instruction *J, SmallVector<Value *, 3> &ReplacedOperands,
357 void replaceOutputsOfPair(LLVMContext& Context, Instruction *I,
358 Instruction *J, Instruction *K,
359 Instruction *&InsertionPt, Instruction *&K1,
362 void collectPairLoadMoveSet(BasicBlock &BB,
363 DenseMap<Value *, Value *> &ChosenPairs,
364 std::multimap<Value *, Value *> &LoadMoveSet,
367 void collectLoadMoveSet(BasicBlock &BB,
368 std::vector<Value *> &PairableInsts,
369 DenseMap<Value *, Value *> &ChosenPairs,
370 std::multimap<Value *, Value *> &LoadMoveSet);
372 bool canMoveUsesOfIAfterJ(BasicBlock &BB,
373 std::multimap<Value *, Value *> &LoadMoveSet,
374 Instruction *I, Instruction *J);
376 void moveUsesOfIAfterJ(BasicBlock &BB,
377 std::multimap<Value *, Value *> &LoadMoveSet,
378 Instruction *&InsertionPt,
379 Instruction *I, Instruction *J);
381 void combineMetadata(Instruction *K, const Instruction *J);
383 bool vectorizeBB(BasicBlock &BB) {
384 if (!DT->isReachableFromEntry(&BB)) {
385 DEBUG(dbgs() << "BBV: skipping unreachable " << BB.getName() <<
386 " in " << BB.getParent()->getName() << "\n");
390 DEBUG(if (VTTI) dbgs() << "BBV: using target information\n");
392 bool changed = false;
393 // Iterate a sufficient number of times to merge types of size 1 bit,
394 // then 2 bits, then 4, etc. up to half of the target vector width of the
395 // target vector register.
398 (VTTI || v <= Config.VectorBits) &&
399 (!Config.MaxIter || n <= Config.MaxIter);
401 DEBUG(dbgs() << "BBV: fusing loop #" << n <<
402 " for " << BB.getName() << " in " <<
403 BB.getParent()->getName() << "...\n");
404 assert(n < 10 && "hrmm, really?");
405 if (vectorizePairs(BB))
411 if (changed && !Pow2LenOnly) {
413 for (; !Config.MaxIter || n <= Config.MaxIter; ++n) {
414 DEBUG(dbgs() << "BBV: fusing for non-2^n-length vectors loop #: " <<
415 n << " for " << BB.getName() << " in " <<
416 BB.getParent()->getName() << "...\n");
417 if (!vectorizePairs(BB, true)) break;
421 DEBUG(dbgs() << "BBV: done!\n");
425 virtual bool runOnBasicBlock(BasicBlock &BB) {
426 AA = &getAnalysis<AliasAnalysis>();
427 DT = &getAnalysis<DominatorTree>();
428 SE = &getAnalysis<ScalarEvolution>();
429 TD = getAnalysisIfAvailable<DataLayout>();
430 TTI = IgnoreTargetInfo ? 0 :
431 getAnalysisIfAvailable<TargetTransformInfo>();
432 VTTI = TTI ? TTI->getVectorTargetTransformInfo() : 0;
434 return vectorizeBB(BB);
437 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
438 BasicBlockPass::getAnalysisUsage(AU);
439 AU.addRequired<AliasAnalysis>();
440 AU.addRequired<DominatorTree>();
441 AU.addRequired<ScalarEvolution>();
442 AU.addPreserved<AliasAnalysis>();
443 AU.addPreserved<DominatorTree>();
444 AU.addPreserved<ScalarEvolution>();
445 AU.setPreservesCFG();
448 static inline VectorType *getVecTypeForPair(Type *ElemTy, Type *Elem2Ty) {
449 assert(ElemTy->getScalarType() == Elem2Ty->getScalarType() &&
450 "Cannot form vector from incompatible scalar types");
451 Type *STy = ElemTy->getScalarType();
454 if (VectorType *VTy = dyn_cast<VectorType>(ElemTy)) {
455 numElem = VTy->getNumElements();
460 if (VectorType *VTy = dyn_cast<VectorType>(Elem2Ty)) {
461 numElem += VTy->getNumElements();
466 return VectorType::get(STy, numElem);
469 static inline void getInstructionTypes(Instruction *I,
470 Type *&T1, Type *&T2) {
471 if (isa<StoreInst>(I)) {
472 // For stores, it is the value type, not the pointer type that matters
473 // because the value is what will come from a vector register.
475 Value *IVal = cast<StoreInst>(I)->getValueOperand();
476 T1 = IVal->getType();
482 T2 = cast<CastInst>(I)->getSrcTy();
486 if (SelectInst *SI = dyn_cast<SelectInst>(I)) {
487 T2 = SI->getCondition()->getType();
488 } else if (ShuffleVectorInst *SI = dyn_cast<ShuffleVectorInst>(I)) {
489 T2 = SI->getOperand(0)->getType();
490 } else if (CmpInst *CI = dyn_cast<CmpInst>(I)) {
491 T2 = CI->getOperand(0)->getType();
495 // Returns the weight associated with the provided value. A chain of
496 // candidate pairs has a length given by the sum of the weights of its
497 // members (one weight per pair; the weight of each member of the pair
498 // is assumed to be the same). This length is then compared to the
499 // chain-length threshold to determine if a given chain is significant
500 // enough to be vectorized. The length is also used in comparing
501 // candidate chains where longer chains are considered to be better.
502 // Note: when this function returns 0, the resulting instructions are
503 // not actually fused.
504 inline size_t getDepthFactor(Value *V) {
505 // InsertElement and ExtractElement have a depth factor of zero. This is
506 // for two reasons: First, they cannot be usefully fused. Second, because
507 // the pass generates a lot of these, they can confuse the simple metric
508 // used to compare the trees in the next iteration. Thus, giving them a
509 // weight of zero allows the pass to essentially ignore them in
510 // subsequent iterations when looking for vectorization opportunities
511 // while still tracking dependency chains that flow through those
513 if (isa<InsertElementInst>(V) || isa<ExtractElementInst>(V))
516 // Give a load or store half of the required depth so that load/store
517 // pairs will vectorize.
518 if (!Config.NoMemOpBoost && (isa<LoadInst>(V) || isa<StoreInst>(V)))
519 return Config.ReqChainDepth/2;
524 // Returns the cost of the provided instruction using VTTI.
525 // This does not handle loads and stores.
526 unsigned getInstrCost(unsigned Opcode, Type *T1, Type *T2) {
529 case Instruction::GetElementPtr:
530 // We mark this instruction as zero-cost because scalar GEPs are usually
531 // lowered to the intruction addressing mode. At the moment we don't
532 // generate vector GEPs.
534 case Instruction::Br:
535 return VTTI->getCFInstrCost(Opcode);
536 case Instruction::PHI:
538 case Instruction::Add:
539 case Instruction::FAdd:
540 case Instruction::Sub:
541 case Instruction::FSub:
542 case Instruction::Mul:
543 case Instruction::FMul:
544 case Instruction::UDiv:
545 case Instruction::SDiv:
546 case Instruction::FDiv:
547 case Instruction::URem:
548 case Instruction::SRem:
549 case Instruction::FRem:
550 case Instruction::Shl:
551 case Instruction::LShr:
552 case Instruction::AShr:
553 case Instruction::And:
554 case Instruction::Or:
555 case Instruction::Xor:
556 return VTTI->getArithmeticInstrCost(Opcode, T1);
557 case Instruction::Select:
558 case Instruction::ICmp:
559 case Instruction::FCmp:
560 return VTTI->getCmpSelInstrCost(Opcode, T1, T2);
561 case Instruction::ZExt:
562 case Instruction::SExt:
563 case Instruction::FPToUI:
564 case Instruction::FPToSI:
565 case Instruction::FPExt:
566 case Instruction::PtrToInt:
567 case Instruction::IntToPtr:
568 case Instruction::SIToFP:
569 case Instruction::UIToFP:
570 case Instruction::Trunc:
571 case Instruction::FPTrunc:
572 case Instruction::BitCast:
573 case Instruction::ShuffleVector:
574 return VTTI->getCastInstrCost(Opcode, T1, T2);
580 // This determines the relative offset of two loads or stores, returning
581 // true if the offset could be determined to be some constant value.
582 // For example, if OffsetInElmts == 1, then J accesses the memory directly
583 // after I; if OffsetInElmts == -1 then I accesses the memory
585 bool getPairPtrInfo(Instruction *I, Instruction *J,
586 Value *&IPtr, Value *&JPtr, unsigned &IAlignment, unsigned &JAlignment,
587 unsigned &IAddressSpace, unsigned &JAddressSpace,
588 int64_t &OffsetInElmts, bool ComputeOffset = true) {
590 if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
591 LoadInst *LJ = cast<LoadInst>(J);
592 IPtr = LI->getPointerOperand();
593 JPtr = LJ->getPointerOperand();
594 IAlignment = LI->getAlignment();
595 JAlignment = LJ->getAlignment();
596 IAddressSpace = LI->getPointerAddressSpace();
597 JAddressSpace = LJ->getPointerAddressSpace();
599 StoreInst *SI = cast<StoreInst>(I), *SJ = cast<StoreInst>(J);
600 IPtr = SI->getPointerOperand();
601 JPtr = SJ->getPointerOperand();
602 IAlignment = SI->getAlignment();
603 JAlignment = SJ->getAlignment();
604 IAddressSpace = SI->getPointerAddressSpace();
605 JAddressSpace = SJ->getPointerAddressSpace();
611 const SCEV *IPtrSCEV = SE->getSCEV(IPtr);
612 const SCEV *JPtrSCEV = SE->getSCEV(JPtr);
614 // If this is a trivial offset, then we'll get something like
615 // 1*sizeof(type). With target data, which we need anyway, this will get
616 // constant folded into a number.
617 const SCEV *OffsetSCEV = SE->getMinusSCEV(JPtrSCEV, IPtrSCEV);
618 if (const SCEVConstant *ConstOffSCEV =
619 dyn_cast<SCEVConstant>(OffsetSCEV)) {
620 ConstantInt *IntOff = ConstOffSCEV->getValue();
621 int64_t Offset = IntOff->getSExtValue();
623 Type *VTy = cast<PointerType>(IPtr->getType())->getElementType();
624 int64_t VTyTSS = (int64_t) TD->getTypeStoreSize(VTy);
626 Type *VTy2 = cast<PointerType>(JPtr->getType())->getElementType();
627 if (VTy != VTy2 && Offset < 0) {
628 int64_t VTy2TSS = (int64_t) TD->getTypeStoreSize(VTy2);
629 OffsetInElmts = Offset/VTy2TSS;
630 return (abs64(Offset) % VTy2TSS) == 0;
633 OffsetInElmts = Offset/VTyTSS;
634 return (abs64(Offset) % VTyTSS) == 0;
640 // Returns true if the provided CallInst represents an intrinsic that can
642 bool isVectorizableIntrinsic(CallInst* I) {
643 Function *F = I->getCalledFunction();
644 if (!F) return false;
646 unsigned IID = F->getIntrinsicID();
647 if (!IID) return false;
652 case Intrinsic::sqrt:
653 case Intrinsic::powi:
657 case Intrinsic::log2:
658 case Intrinsic::log10:
660 case Intrinsic::exp2:
662 return Config.VectorizeMath;
664 return Config.VectorizeFMA;
668 // Returns true if J is the second element in some pair referenced by
669 // some multimap pair iterator pair.
670 template <typename V>
671 bool isSecondInIteratorPair(V J, std::pair<
672 typename std::multimap<V, V>::iterator,
673 typename std::multimap<V, V>::iterator> PairRange) {
674 for (typename std::multimap<V, V>::iterator K = PairRange.first;
675 K != PairRange.second; ++K)
676 if (K->second == J) return true;
682 // This function implements one vectorization iteration on the provided
683 // basic block. It returns true if the block is changed.
684 bool BBVectorize::vectorizePairs(BasicBlock &BB, bool NonPow2Len) {
686 BasicBlock::iterator Start = BB.getFirstInsertionPt();
688 std::vector<Value *> AllPairableInsts;
689 DenseMap<Value *, Value *> AllChosenPairs;
690 DenseSet<ValuePair> AllFixedOrderPairs;
691 DenseMap<VPPair, unsigned> AllPairConnectionTypes;
692 std::multimap<ValuePair, ValuePair> AllConnectedPairs, AllConnectedPairDeps;
695 std::vector<Value *> PairableInsts;
696 std::multimap<Value *, Value *> CandidatePairs;
697 DenseSet<ValuePair> FixedOrderPairs;
698 DenseMap<ValuePair, int> CandidatePairCostSavings;
699 ShouldContinue = getCandidatePairs(BB, Start, CandidatePairs,
701 CandidatePairCostSavings,
702 PairableInsts, NonPow2Len);
703 if (PairableInsts.empty()) continue;
705 // Now we have a map of all of the pairable instructions and we need to
706 // select the best possible pairing. A good pairing is one such that the
707 // users of the pair are also paired. This defines a (directed) forest
708 // over the pairs such that two pairs are connected iff the second pair
711 // Note that it only matters that both members of the second pair use some
712 // element of the first pair (to allow for splatting).
714 std::multimap<ValuePair, ValuePair> ConnectedPairs, ConnectedPairDeps;
715 DenseMap<VPPair, unsigned> PairConnectionTypes;
716 computeConnectedPairs(CandidatePairs, PairableInsts, ConnectedPairs,
717 PairConnectionTypes);
718 if (ConnectedPairs.empty()) continue;
720 for (std::multimap<ValuePair, ValuePair>::iterator
721 I = ConnectedPairs.begin(), IE = ConnectedPairs.end();
723 ConnectedPairDeps.insert(VPPair(I->second, I->first));
726 // Build the pairable-instruction dependency map
727 DenseSet<ValuePair> PairableInstUsers;
728 buildDepMap(BB, CandidatePairs, PairableInsts, PairableInstUsers);
730 // There is now a graph of the connected pairs. For each variable, pick
731 // the pairing with the largest tree meeting the depth requirement on at
732 // least one branch. Then select all pairings that are part of that tree
733 // and remove them from the list of available pairings and pairable
736 DenseMap<Value *, Value *> ChosenPairs;
737 choosePairs(CandidatePairs, CandidatePairCostSavings,
738 PairableInsts, FixedOrderPairs, PairConnectionTypes,
739 ConnectedPairs, ConnectedPairDeps,
740 PairableInstUsers, ChosenPairs);
742 if (ChosenPairs.empty()) continue;
743 AllPairableInsts.insert(AllPairableInsts.end(), PairableInsts.begin(),
744 PairableInsts.end());
745 AllChosenPairs.insert(ChosenPairs.begin(), ChosenPairs.end());
747 // Only for the chosen pairs, propagate information on fixed-order pairs,
748 // pair connections, and their types to the data structures used by the
749 // pair fusion procedures.
750 for (DenseMap<Value *, Value *>::iterator I = ChosenPairs.begin(),
751 IE = ChosenPairs.end(); I != IE; ++I) {
752 if (FixedOrderPairs.count(*I))
753 AllFixedOrderPairs.insert(*I);
754 else if (FixedOrderPairs.count(ValuePair(I->second, I->first)))
755 AllFixedOrderPairs.insert(ValuePair(I->second, I->first));
757 for (DenseMap<Value *, Value *>::iterator J = ChosenPairs.begin();
759 DenseMap<VPPair, unsigned>::iterator K =
760 PairConnectionTypes.find(VPPair(*I, *J));
761 if (K != PairConnectionTypes.end()) {
762 AllPairConnectionTypes.insert(*K);
764 K = PairConnectionTypes.find(VPPair(*J, *I));
765 if (K != PairConnectionTypes.end())
766 AllPairConnectionTypes.insert(*K);
771 for (std::multimap<ValuePair, ValuePair>::iterator
772 I = ConnectedPairs.begin(), IE = ConnectedPairs.end();
774 if (AllPairConnectionTypes.count(*I)) {
775 AllConnectedPairs.insert(*I);
776 AllConnectedPairDeps.insert(VPPair(I->second, I->first));
779 } while (ShouldContinue);
781 if (AllChosenPairs.empty()) return false;
782 NumFusedOps += AllChosenPairs.size();
784 // A set of pairs has now been selected. It is now necessary to replace the
785 // paired instructions with vector instructions. For this procedure each
786 // operand must be replaced with a vector operand. This vector is formed
787 // by using build_vector on the old operands. The replaced values are then
788 // replaced with a vector_extract on the result. Subsequent optimization
789 // passes should coalesce the build/extract combinations.
791 fuseChosenPairs(BB, AllPairableInsts, AllChosenPairs, AllFixedOrderPairs,
792 AllPairConnectionTypes,
793 AllConnectedPairs, AllConnectedPairDeps);
795 // It is important to cleanup here so that future iterations of this
796 // function have less work to do.
797 (void) SimplifyInstructionsInBlock(&BB, TD, AA->getTargetLibraryInfo());
801 // This function returns true if the provided instruction is capable of being
802 // fused into a vector instruction. This determination is based only on the
803 // type and other attributes of the instruction.
804 bool BBVectorize::isInstVectorizable(Instruction *I,
805 bool &IsSimpleLoadStore) {
806 IsSimpleLoadStore = false;
808 if (CallInst *C = dyn_cast<CallInst>(I)) {
809 if (!isVectorizableIntrinsic(C))
811 } else if (LoadInst *L = dyn_cast<LoadInst>(I)) {
812 // Vectorize simple loads if possbile:
813 IsSimpleLoadStore = L->isSimple();
814 if (!IsSimpleLoadStore || !Config.VectorizeMemOps)
816 } else if (StoreInst *S = dyn_cast<StoreInst>(I)) {
817 // Vectorize simple stores if possbile:
818 IsSimpleLoadStore = S->isSimple();
819 if (!IsSimpleLoadStore || !Config.VectorizeMemOps)
821 } else if (CastInst *C = dyn_cast<CastInst>(I)) {
822 // We can vectorize casts, but not casts of pointer types, etc.
823 if (!Config.VectorizeCasts)
826 Type *SrcTy = C->getSrcTy();
827 if (!SrcTy->isSingleValueType())
830 Type *DestTy = C->getDestTy();
831 if (!DestTy->isSingleValueType())
833 } else if (isa<SelectInst>(I)) {
834 if (!Config.VectorizeSelect)
836 } else if (isa<CmpInst>(I)) {
837 if (!Config.VectorizeCmp)
839 } else if (GetElementPtrInst *G = dyn_cast<GetElementPtrInst>(I)) {
840 if (!Config.VectorizeGEP)
843 // Currently, vector GEPs exist only with one index.
844 if (G->getNumIndices() != 1)
846 } else if (!(I->isBinaryOp() || isa<ShuffleVectorInst>(I) ||
847 isa<ExtractElementInst>(I) || isa<InsertElementInst>(I))) {
851 // We can't vectorize memory operations without target data
852 if (TD == 0 && IsSimpleLoadStore)
856 getInstructionTypes(I, T1, T2);
858 // Not every type can be vectorized...
859 if (!(VectorType::isValidElementType(T1) || T1->isVectorTy()) ||
860 !(VectorType::isValidElementType(T2) || T2->isVectorTy()))
863 if (T1->getScalarSizeInBits() == 1) {
864 if (!Config.VectorizeBools)
867 if (!Config.VectorizeInts && T1->isIntOrIntVectorTy())
871 if (T2->getScalarSizeInBits() == 1) {
872 if (!Config.VectorizeBools)
875 if (!Config.VectorizeInts && T2->isIntOrIntVectorTy())
879 if (!Config.VectorizeFloats
880 && (T1->isFPOrFPVectorTy() || T2->isFPOrFPVectorTy()))
883 // Don't vectorize target-specific types.
884 if (T1->isX86_FP80Ty() || T1->isPPC_FP128Ty() || T1->isX86_MMXTy())
886 if (T2->isX86_FP80Ty() || T2->isPPC_FP128Ty() || T2->isX86_MMXTy())
889 if ((!Config.VectorizePointers || TD == 0) &&
890 (T1->getScalarType()->isPointerTy() ||
891 T2->getScalarType()->isPointerTy()))
894 if (!VTTI && (T1->getPrimitiveSizeInBits() >= Config.VectorBits ||
895 T2->getPrimitiveSizeInBits() >= Config.VectorBits))
901 // This function returns true if the two provided instructions are compatible
902 // (meaning that they can be fused into a vector instruction). This assumes
903 // that I has already been determined to be vectorizable and that J is not
904 // in the use tree of I.
905 bool BBVectorize::areInstsCompatible(Instruction *I, Instruction *J,
906 bool IsSimpleLoadStore, bool NonPow2Len,
907 int &CostSavings, int &FixedOrder) {
908 DEBUG(if (DebugInstructionExamination) dbgs() << "BBV: looking at " << *I <<
909 " <-> " << *J << "\n");
914 // Loads and stores can be merged if they have different alignments,
915 // but are otherwise the same.
916 if (!J->isSameOperationAs(I, Instruction::CompareIgnoringAlignment |
917 (NonPow2Len ? Instruction::CompareUsingScalarTypes : 0)))
920 Type *IT1, *IT2, *JT1, *JT2;
921 getInstructionTypes(I, IT1, IT2);
922 getInstructionTypes(J, JT1, JT2);
923 unsigned MaxTypeBits = std::max(
924 IT1->getPrimitiveSizeInBits() + JT1->getPrimitiveSizeInBits(),
925 IT2->getPrimitiveSizeInBits() + JT2->getPrimitiveSizeInBits());
926 if (!VTTI && MaxTypeBits > Config.VectorBits)
929 // FIXME: handle addsub-type operations!
931 if (IsSimpleLoadStore) {
933 unsigned IAlignment, JAlignment, IAddressSpace, JAddressSpace;
934 int64_t OffsetInElmts = 0;
935 if (getPairPtrInfo(I, J, IPtr, JPtr, IAlignment, JAlignment,
936 IAddressSpace, JAddressSpace,
937 OffsetInElmts) && abs64(OffsetInElmts) == 1) {
938 FixedOrder = (int) OffsetInElmts;
939 unsigned BottomAlignment = IAlignment;
940 if (OffsetInElmts < 0) BottomAlignment = JAlignment;
942 Type *aTypeI = isa<StoreInst>(I) ?
943 cast<StoreInst>(I)->getValueOperand()->getType() : I->getType();
944 Type *aTypeJ = isa<StoreInst>(J) ?
945 cast<StoreInst>(J)->getValueOperand()->getType() : J->getType();
946 Type *VType = getVecTypeForPair(aTypeI, aTypeJ);
948 if (Config.AlignedOnly) {
949 // An aligned load or store is possible only if the instruction
950 // with the lower offset has an alignment suitable for the
953 unsigned VecAlignment = TD->getPrefTypeAlignment(VType);
954 if (BottomAlignment < VecAlignment)
959 unsigned ICost = VTTI->getMemoryOpCost(I->getOpcode(), I->getType(),
960 IAlignment, IAddressSpace);
961 unsigned JCost = VTTI->getMemoryOpCost(J->getOpcode(), J->getType(),
962 JAlignment, JAddressSpace);
963 unsigned VCost = VTTI->getMemoryOpCost(I->getOpcode(), VType,
966 if (VCost > ICost + JCost)
969 // We don't want to fuse to a type that will be split, even
970 // if the two input types will also be split and there is no other
972 unsigned VParts = VTTI->getNumberOfParts(VType);
975 else if (!VParts && VCost == ICost + JCost)
978 CostSavings = ICost + JCost - VCost;
984 unsigned ICost = getInstrCost(I->getOpcode(), IT1, IT2);
985 unsigned JCost = getInstrCost(J->getOpcode(), JT1, JT2);
986 Type *VT1 = getVecTypeForPair(IT1, JT1),
987 *VT2 = getVecTypeForPair(IT2, JT2);
988 unsigned VCost = getInstrCost(I->getOpcode(), VT1, VT2);
990 if (VCost > ICost + JCost)
993 // We don't want to fuse to a type that will be split, even
994 // if the two input types will also be split and there is no other
996 unsigned VParts1 = VTTI->getNumberOfParts(VT1),
997 VParts2 = VTTI->getNumberOfParts(VT2);
998 if (VParts1 > 1 || VParts2 > 1)
1000 else if ((!VParts1 || !VParts2) && VCost == ICost + JCost)
1003 CostSavings = ICost + JCost - VCost;
1006 // The powi intrinsic is special because only the first argument is
1007 // vectorized, the second arguments must be equal.
1008 CallInst *CI = dyn_cast<CallInst>(I);
1010 if (CI && (FI = CI->getCalledFunction()) &&
1011 FI->getIntrinsicID() == Intrinsic::powi) {
1013 Value *A1I = CI->getArgOperand(1),
1014 *A1J = cast<CallInst>(J)->getArgOperand(1);
1015 const SCEV *A1ISCEV = SE->getSCEV(A1I),
1016 *A1JSCEV = SE->getSCEV(A1J);
1017 return (A1ISCEV == A1JSCEV);
1023 // Figure out whether or not J uses I and update the users and write-set
1024 // structures associated with I. Specifically, Users represents the set of
1025 // instructions that depend on I. WriteSet represents the set
1026 // of memory locations that are dependent on I. If UpdateUsers is true,
1027 // and J uses I, then Users is updated to contain J and WriteSet is updated
1028 // to contain any memory locations to which J writes. The function returns
1029 // true if J uses I. By default, alias analysis is used to determine
1030 // whether J reads from memory that overlaps with a location in WriteSet.
1031 // If LoadMoveSet is not null, then it is a previously-computed multimap
1032 // where the key is the memory-based user instruction and the value is
1033 // the instruction to be compared with I. So, if LoadMoveSet is provided,
1034 // then the alias analysis is not used. This is necessary because this
1035 // function is called during the process of moving instructions during
1036 // vectorization and the results of the alias analysis are not stable during
1038 bool BBVectorize::trackUsesOfI(DenseSet<Value *> &Users,
1039 AliasSetTracker &WriteSet, Instruction *I,
1040 Instruction *J, bool UpdateUsers,
1041 std::multimap<Value *, Value *> *LoadMoveSet) {
1044 // This instruction may already be marked as a user due, for example, to
1045 // being a member of a selected pair.
1050 for (User::op_iterator JU = J->op_begin(), JE = J->op_end();
1053 if (I == V || Users.count(V)) {
1058 if (!UsesI && J->mayReadFromMemory()) {
1060 VPIteratorPair JPairRange = LoadMoveSet->equal_range(J);
1061 UsesI = isSecondInIteratorPair<Value*>(I, JPairRange);
1063 for (AliasSetTracker::iterator W = WriteSet.begin(),
1064 WE = WriteSet.end(); W != WE; ++W) {
1065 if (W->aliasesUnknownInst(J, *AA)) {
1073 if (UsesI && UpdateUsers) {
1074 if (J->mayWriteToMemory()) WriteSet.add(J);
1081 // This function iterates over all instruction pairs in the provided
1082 // basic block and collects all candidate pairs for vectorization.
1083 bool BBVectorize::getCandidatePairs(BasicBlock &BB,
1084 BasicBlock::iterator &Start,
1085 std::multimap<Value *, Value *> &CandidatePairs,
1086 DenseSet<ValuePair> &FixedOrderPairs,
1087 DenseMap<ValuePair, int> &CandidatePairCostSavings,
1088 std::vector<Value *> &PairableInsts, bool NonPow2Len) {
1089 BasicBlock::iterator E = BB.end();
1090 if (Start == E) return false;
1092 bool ShouldContinue = false, IAfterStart = false;
1093 for (BasicBlock::iterator I = Start++; I != E; ++I) {
1094 if (I == Start) IAfterStart = true;
1096 bool IsSimpleLoadStore;
1097 if (!isInstVectorizable(I, IsSimpleLoadStore)) continue;
1099 // Look for an instruction with which to pair instruction *I...
1100 DenseSet<Value *> Users;
1101 AliasSetTracker WriteSet(*AA);
1102 bool JAfterStart = IAfterStart;
1103 BasicBlock::iterator J = llvm::next(I);
1104 for (unsigned ss = 0; J != E && ss <= Config.SearchLimit; ++J, ++ss) {
1105 if (J == Start) JAfterStart = true;
1107 // Determine if J uses I, if so, exit the loop.
1108 bool UsesI = trackUsesOfI(Users, WriteSet, I, J, !Config.FastDep);
1109 if (Config.FastDep) {
1110 // Note: For this heuristic to be effective, independent operations
1111 // must tend to be intermixed. This is likely to be true from some
1112 // kinds of grouped loop unrolling (but not the generic LLVM pass),
1113 // but otherwise may require some kind of reordering pass.
1115 // When using fast dependency analysis,
1116 // stop searching after first use:
1119 if (UsesI) continue;
1122 // J does not use I, and comes before the first use of I, so it can be
1123 // merged with I if the instructions are compatible.
1124 int CostSavings, FixedOrder;
1125 if (!areInstsCompatible(I, J, IsSimpleLoadStore, NonPow2Len,
1126 CostSavings, FixedOrder)) continue;
1128 // J is a candidate for merging with I.
1129 if (!PairableInsts.size() ||
1130 PairableInsts[PairableInsts.size()-1] != I) {
1131 PairableInsts.push_back(I);
1134 CandidatePairs.insert(ValuePair(I, J));
1136 CandidatePairCostSavings.insert(ValuePairWithCost(ValuePair(I, J),
1139 if (FixedOrder == 1)
1140 FixedOrderPairs.insert(ValuePair(I, J));
1141 else if (FixedOrder == -1)
1142 FixedOrderPairs.insert(ValuePair(J, I));
1144 // The next call to this function must start after the last instruction
1145 // selected during this invocation.
1147 Start = llvm::next(J);
1148 IAfterStart = JAfterStart = false;
1151 DEBUG(if (DebugCandidateSelection) dbgs() << "BBV: candidate pair "
1152 << *I << " <-> " << *J << " (cost savings: " <<
1153 CostSavings << ")\n");
1155 // If we have already found too many pairs, break here and this function
1156 // will be called again starting after the last instruction selected
1157 // during this invocation.
1158 if (PairableInsts.size() >= Config.MaxInsts) {
1159 ShouldContinue = true;
1168 DEBUG(dbgs() << "BBV: found " << PairableInsts.size()
1169 << " instructions with candidate pairs\n");
1171 return ShouldContinue;
1174 // Finds candidate pairs connected to the pair P = <PI, PJ>. This means that
1175 // it looks for pairs such that both members have an input which is an
1176 // output of PI or PJ.
1177 void BBVectorize::computePairsConnectedTo(
1178 std::multimap<Value *, Value *> &CandidatePairs,
1179 std::vector<Value *> &PairableInsts,
1180 std::multimap<ValuePair, ValuePair> &ConnectedPairs,
1181 DenseMap<VPPair, unsigned> &PairConnectionTypes,
1185 // For each possible pairing for this variable, look at the uses of
1186 // the first value...
1187 for (Value::use_iterator I = P.first->use_begin(),
1188 E = P.first->use_end(); I != E; ++I) {
1189 if (isa<LoadInst>(*I)) {
1190 // A pair cannot be connected to a load because the load only takes one
1191 // operand (the address) and it is a scalar even after vectorization.
1193 } else if ((SI = dyn_cast<StoreInst>(*I)) &&
1194 P.first == SI->getPointerOperand()) {
1195 // Similarly, a pair cannot be connected to a store through its
1200 VPIteratorPair IPairRange = CandidatePairs.equal_range(*I);
1202 // For each use of the first variable, look for uses of the second
1204 for (Value::use_iterator J = P.second->use_begin(),
1205 E2 = P.second->use_end(); J != E2; ++J) {
1206 if ((SJ = dyn_cast<StoreInst>(*J)) &&
1207 P.second == SJ->getPointerOperand())
1210 VPIteratorPair JPairRange = CandidatePairs.equal_range(*J);
1213 if (isSecondInIteratorPair<Value*>(*J, IPairRange)) {
1214 VPPair VP(P, ValuePair(*I, *J));
1215 ConnectedPairs.insert(VP);
1216 PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionDirect));
1220 if (isSecondInIteratorPair<Value*>(*I, JPairRange)) {
1221 VPPair VP(P, ValuePair(*J, *I));
1222 ConnectedPairs.insert(VP);
1223 PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionSwap));
1227 if (Config.SplatBreaksChain) continue;
1228 // Look for cases where just the first value in the pair is used by
1229 // both members of another pair (splatting).
1230 for (Value::use_iterator J = P.first->use_begin(); J != E; ++J) {
1231 if ((SJ = dyn_cast<StoreInst>(*J)) &&
1232 P.first == SJ->getPointerOperand())
1235 if (isSecondInIteratorPair<Value*>(*J, IPairRange)) {
1236 VPPair VP(P, ValuePair(*I, *J));
1237 ConnectedPairs.insert(VP);
1238 PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionSplat));
1243 if (Config.SplatBreaksChain) return;
1244 // Look for cases where just the second value in the pair is used by
1245 // both members of another pair (splatting).
1246 for (Value::use_iterator I = P.second->use_begin(),
1247 E = P.second->use_end(); I != E; ++I) {
1248 if (isa<LoadInst>(*I))
1250 else if ((SI = dyn_cast<StoreInst>(*I)) &&
1251 P.second == SI->getPointerOperand())
1254 VPIteratorPair IPairRange = CandidatePairs.equal_range(*I);
1256 for (Value::use_iterator J = P.second->use_begin(); J != E; ++J) {
1257 if ((SJ = dyn_cast<StoreInst>(*J)) &&
1258 P.second == SJ->getPointerOperand())
1261 if (isSecondInIteratorPair<Value*>(*J, IPairRange)) {
1262 VPPair VP(P, ValuePair(*I, *J));
1263 ConnectedPairs.insert(VP);
1264 PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionSplat));
1270 // This function figures out which pairs are connected. Two pairs are
1271 // connected if some output of the first pair forms an input to both members
1272 // of the second pair.
1273 void BBVectorize::computeConnectedPairs(
1274 std::multimap<Value *, Value *> &CandidatePairs,
1275 std::vector<Value *> &PairableInsts,
1276 std::multimap<ValuePair, ValuePair> &ConnectedPairs,
1277 DenseMap<VPPair, unsigned> &PairConnectionTypes) {
1279 for (std::vector<Value *>::iterator PI = PairableInsts.begin(),
1280 PE = PairableInsts.end(); PI != PE; ++PI) {
1281 VPIteratorPair choiceRange = CandidatePairs.equal_range(*PI);
1283 for (std::multimap<Value *, Value *>::iterator P = choiceRange.first;
1284 P != choiceRange.second; ++P)
1285 computePairsConnectedTo(CandidatePairs, PairableInsts,
1286 ConnectedPairs, PairConnectionTypes, *P);
1289 DEBUG(dbgs() << "BBV: found " << ConnectedPairs.size()
1290 << " pair connections.\n");
1293 // This function builds a set of use tuples such that <A, B> is in the set
1294 // if B is in the use tree of A. If B is in the use tree of A, then B
1295 // depends on the output of A.
1296 void BBVectorize::buildDepMap(
1298 std::multimap<Value *, Value *> &CandidatePairs,
1299 std::vector<Value *> &PairableInsts,
1300 DenseSet<ValuePair> &PairableInstUsers) {
1301 DenseSet<Value *> IsInPair;
1302 for (std::multimap<Value *, Value *>::iterator C = CandidatePairs.begin(),
1303 E = CandidatePairs.end(); C != E; ++C) {
1304 IsInPair.insert(C->first);
1305 IsInPair.insert(C->second);
1308 // Iterate through the basic block, recording all Users of each
1309 // pairable instruction.
1311 BasicBlock::iterator E = BB.end();
1312 for (BasicBlock::iterator I = BB.getFirstInsertionPt(); I != E; ++I) {
1313 if (IsInPair.find(I) == IsInPair.end()) continue;
1315 DenseSet<Value *> Users;
1316 AliasSetTracker WriteSet(*AA);
1317 for (BasicBlock::iterator J = llvm::next(I); J != E; ++J)
1318 (void) trackUsesOfI(Users, WriteSet, I, J);
1320 for (DenseSet<Value *>::iterator U = Users.begin(), E = Users.end();
1322 PairableInstUsers.insert(ValuePair(I, *U));
1326 // Returns true if an input to pair P is an output of pair Q and also an
1327 // input of pair Q is an output of pair P. If this is the case, then these
1328 // two pairs cannot be simultaneously fused.
1329 bool BBVectorize::pairsConflict(ValuePair P, ValuePair Q,
1330 DenseSet<ValuePair> &PairableInstUsers,
1331 std::multimap<ValuePair, ValuePair> *PairableInstUserMap) {
1332 // Two pairs are in conflict if they are mutual Users of eachother.
1333 bool QUsesP = PairableInstUsers.count(ValuePair(P.first, Q.first)) ||
1334 PairableInstUsers.count(ValuePair(P.first, Q.second)) ||
1335 PairableInstUsers.count(ValuePair(P.second, Q.first)) ||
1336 PairableInstUsers.count(ValuePair(P.second, Q.second));
1337 bool PUsesQ = PairableInstUsers.count(ValuePair(Q.first, P.first)) ||
1338 PairableInstUsers.count(ValuePair(Q.first, P.second)) ||
1339 PairableInstUsers.count(ValuePair(Q.second, P.first)) ||
1340 PairableInstUsers.count(ValuePair(Q.second, P.second));
1341 if (PairableInstUserMap) {
1342 // FIXME: The expensive part of the cycle check is not so much the cycle
1343 // check itself but this edge insertion procedure. This needs some
1344 // profiling and probably a different data structure (same is true of
1345 // most uses of std::multimap).
1347 VPPIteratorPair QPairRange = PairableInstUserMap->equal_range(Q);
1348 if (!isSecondInIteratorPair(P, QPairRange))
1349 PairableInstUserMap->insert(VPPair(Q, P));
1352 VPPIteratorPair PPairRange = PairableInstUserMap->equal_range(P);
1353 if (!isSecondInIteratorPair(Q, PPairRange))
1354 PairableInstUserMap->insert(VPPair(P, Q));
1358 return (QUsesP && PUsesQ);
1361 // This function walks the use graph of current pairs to see if, starting
1362 // from P, the walk returns to P.
1363 bool BBVectorize::pairWillFormCycle(ValuePair P,
1364 std::multimap<ValuePair, ValuePair> &PairableInstUserMap,
1365 DenseSet<ValuePair> &CurrentPairs) {
1366 DEBUG(if (DebugCycleCheck)
1367 dbgs() << "BBV: starting cycle check for : " << *P.first << " <-> "
1368 << *P.second << "\n");
1369 // A lookup table of visisted pairs is kept because the PairableInstUserMap
1370 // contains non-direct associations.
1371 DenseSet<ValuePair> Visited;
1372 SmallVector<ValuePair, 32> Q;
1373 // General depth-first post-order traversal:
1376 ValuePair QTop = Q.pop_back_val();
1377 Visited.insert(QTop);
1379 DEBUG(if (DebugCycleCheck)
1380 dbgs() << "BBV: cycle check visiting: " << *QTop.first << " <-> "
1381 << *QTop.second << "\n");
1382 VPPIteratorPair QPairRange = PairableInstUserMap.equal_range(QTop);
1383 for (std::multimap<ValuePair, ValuePair>::iterator C = QPairRange.first;
1384 C != QPairRange.second; ++C) {
1385 if (C->second == P) {
1387 << "BBV: rejected to prevent non-trivial cycle formation: "
1388 << *C->first.first << " <-> " << *C->first.second << "\n");
1392 if (CurrentPairs.count(C->second) && !Visited.count(C->second))
1393 Q.push_back(C->second);
1395 } while (!Q.empty());
1400 // This function builds the initial tree of connected pairs with the
1401 // pair J at the root.
1402 void BBVectorize::buildInitialTreeFor(
1403 std::multimap<Value *, Value *> &CandidatePairs,
1404 std::vector<Value *> &PairableInsts,
1405 std::multimap<ValuePair, ValuePair> &ConnectedPairs,
1406 DenseSet<ValuePair> &PairableInstUsers,
1407 DenseMap<Value *, Value *> &ChosenPairs,
1408 DenseMap<ValuePair, size_t> &Tree, ValuePair J) {
1409 // Each of these pairs is viewed as the root node of a Tree. The Tree
1410 // is then walked (depth-first). As this happens, we keep track of
1411 // the pairs that compose the Tree and the maximum depth of the Tree.
1412 SmallVector<ValuePairWithDepth, 32> Q;
1413 // General depth-first post-order traversal:
1414 Q.push_back(ValuePairWithDepth(J, getDepthFactor(J.first)));
1416 ValuePairWithDepth QTop = Q.back();
1418 // Push each child onto the queue:
1419 bool MoreChildren = false;
1420 size_t MaxChildDepth = QTop.second;
1421 VPPIteratorPair qtRange = ConnectedPairs.equal_range(QTop.first);
1422 for (std::multimap<ValuePair, ValuePair>::iterator k = qtRange.first;
1423 k != qtRange.second; ++k) {
1424 // Make sure that this child pair is still a candidate:
1425 bool IsStillCand = false;
1426 VPIteratorPair checkRange =
1427 CandidatePairs.equal_range(k->second.first);
1428 for (std::multimap<Value *, Value *>::iterator m = checkRange.first;
1429 m != checkRange.second; ++m) {
1430 if (m->second == k->second.second) {
1437 DenseMap<ValuePair, size_t>::iterator C = Tree.find(k->second);
1438 if (C == Tree.end()) {
1439 size_t d = getDepthFactor(k->second.first);
1440 Q.push_back(ValuePairWithDepth(k->second, QTop.second+d));
1441 MoreChildren = true;
1443 MaxChildDepth = std::max(MaxChildDepth, C->second);
1448 if (!MoreChildren) {
1449 // Record the current pair as part of the Tree:
1450 Tree.insert(ValuePairWithDepth(QTop.first, MaxChildDepth));
1453 } while (!Q.empty());
1456 // Given some initial tree, prune it by removing conflicting pairs (pairs
1457 // that cannot be simultaneously chosen for vectorization).
1458 void BBVectorize::pruneTreeFor(
1459 std::multimap<Value *, Value *> &CandidatePairs,
1460 std::vector<Value *> &PairableInsts,
1461 std::multimap<ValuePair, ValuePair> &ConnectedPairs,
1462 DenseSet<ValuePair> &PairableInstUsers,
1463 std::multimap<ValuePair, ValuePair> &PairableInstUserMap,
1464 DenseMap<Value *, Value *> &ChosenPairs,
1465 DenseMap<ValuePair, size_t> &Tree,
1466 DenseSet<ValuePair> &PrunedTree, ValuePair J,
1467 bool UseCycleCheck) {
1468 SmallVector<ValuePairWithDepth, 32> Q;
1469 // General depth-first post-order traversal:
1470 Q.push_back(ValuePairWithDepth(J, getDepthFactor(J.first)));
1472 ValuePairWithDepth QTop = Q.pop_back_val();
1473 PrunedTree.insert(QTop.first);
1475 // Visit each child, pruning as necessary...
1476 DenseMap<ValuePair, size_t> BestChildren;
1477 VPPIteratorPair QTopRange = ConnectedPairs.equal_range(QTop.first);
1478 for (std::multimap<ValuePair, ValuePair>::iterator K = QTopRange.first;
1479 K != QTopRange.second; ++K) {
1480 DenseMap<ValuePair, size_t>::iterator C = Tree.find(K->second);
1481 if (C == Tree.end()) continue;
1483 // This child is in the Tree, now we need to make sure it is the
1484 // best of any conflicting children. There could be multiple
1485 // conflicting children, so first, determine if we're keeping
1486 // this child, then delete conflicting children as necessary.
1488 // It is also necessary to guard against pairing-induced
1489 // dependencies. Consider instructions a .. x .. y .. b
1490 // such that (a,b) are to be fused and (x,y) are to be fused
1491 // but a is an input to x and b is an output from y. This
1492 // means that y cannot be moved after b but x must be moved
1493 // after b for (a,b) to be fused. In other words, after
1494 // fusing (a,b) we have y .. a/b .. x where y is an input
1495 // to a/b and x is an output to a/b: x and y can no longer
1496 // be legally fused. To prevent this condition, we must
1497 // make sure that a child pair added to the Tree is not
1498 // both an input and output of an already-selected pair.
1500 // Pairing-induced dependencies can also form from more complicated
1501 // cycles. The pair vs. pair conflicts are easy to check, and so
1502 // that is done explicitly for "fast rejection", and because for
1503 // child vs. child conflicts, we may prefer to keep the current
1504 // pair in preference to the already-selected child.
1505 DenseSet<ValuePair> CurrentPairs;
1508 for (DenseMap<ValuePair, size_t>::iterator C2
1509 = BestChildren.begin(), E2 = BestChildren.end();
1511 if (C2->first.first == C->first.first ||
1512 C2->first.first == C->first.second ||
1513 C2->first.second == C->first.first ||
1514 C2->first.second == C->first.second ||
1515 pairsConflict(C2->first, C->first, PairableInstUsers,
1516 UseCycleCheck ? &PairableInstUserMap : 0)) {
1517 if (C2->second >= C->second) {
1522 CurrentPairs.insert(C2->first);
1525 if (!CanAdd) continue;
1527 // Even worse, this child could conflict with another node already
1528 // selected for the Tree. If that is the case, ignore this child.
1529 for (DenseSet<ValuePair>::iterator T = PrunedTree.begin(),
1530 E2 = PrunedTree.end(); T != E2; ++T) {
1531 if (T->first == C->first.first ||
1532 T->first == C->first.second ||
1533 T->second == C->first.first ||
1534 T->second == C->first.second ||
1535 pairsConflict(*T, C->first, PairableInstUsers,
1536 UseCycleCheck ? &PairableInstUserMap : 0)) {
1541 CurrentPairs.insert(*T);
1543 if (!CanAdd) continue;
1545 // And check the queue too...
1546 for (SmallVector<ValuePairWithDepth, 32>::iterator C2 = Q.begin(),
1547 E2 = Q.end(); C2 != E2; ++C2) {
1548 if (C2->first.first == C->first.first ||
1549 C2->first.first == C->first.second ||
1550 C2->first.second == C->first.first ||
1551 C2->first.second == C->first.second ||
1552 pairsConflict(C2->first, C->first, PairableInstUsers,
1553 UseCycleCheck ? &PairableInstUserMap : 0)) {
1558 CurrentPairs.insert(C2->first);
1560 if (!CanAdd) continue;
1562 // Last but not least, check for a conflict with any of the
1563 // already-chosen pairs.
1564 for (DenseMap<Value *, Value *>::iterator C2 =
1565 ChosenPairs.begin(), E2 = ChosenPairs.end();
1567 if (pairsConflict(*C2, C->first, PairableInstUsers,
1568 UseCycleCheck ? &PairableInstUserMap : 0)) {
1573 CurrentPairs.insert(*C2);
1575 if (!CanAdd) continue;
1577 // To check for non-trivial cycles formed by the addition of the
1578 // current pair we've formed a list of all relevant pairs, now use a
1579 // graph walk to check for a cycle. We start from the current pair and
1580 // walk the use tree to see if we again reach the current pair. If we
1581 // do, then the current pair is rejected.
1583 // FIXME: It may be more efficient to use a topological-ordering
1584 // algorithm to improve the cycle check. This should be investigated.
1585 if (UseCycleCheck &&
1586 pairWillFormCycle(C->first, PairableInstUserMap, CurrentPairs))
1589 // This child can be added, but we may have chosen it in preference
1590 // to an already-selected child. Check for this here, and if a
1591 // conflict is found, then remove the previously-selected child
1592 // before adding this one in its place.
1593 for (DenseMap<ValuePair, size_t>::iterator C2
1594 = BestChildren.begin(); C2 != BestChildren.end();) {
1595 if (C2->first.first == C->first.first ||
1596 C2->first.first == C->first.second ||
1597 C2->first.second == C->first.first ||
1598 C2->first.second == C->first.second ||
1599 pairsConflict(C2->first, C->first, PairableInstUsers))
1600 BestChildren.erase(C2++);
1605 BestChildren.insert(ValuePairWithDepth(C->first, C->second));
1608 for (DenseMap<ValuePair, size_t>::iterator C
1609 = BestChildren.begin(), E2 = BestChildren.end();
1611 size_t DepthF = getDepthFactor(C->first.first);
1612 Q.push_back(ValuePairWithDepth(C->first, QTop.second+DepthF));
1614 } while (!Q.empty());
1617 // This function finds the best tree of mututally-compatible connected
1618 // pairs, given the choice of root pairs as an iterator range.
1619 void BBVectorize::findBestTreeFor(
1620 std::multimap<Value *, Value *> &CandidatePairs,
1621 DenseMap<ValuePair, int> &CandidatePairCostSavings,
1622 std::vector<Value *> &PairableInsts,
1623 DenseSet<ValuePair> &FixedOrderPairs,
1624 DenseMap<VPPair, unsigned> &PairConnectionTypes,
1625 std::multimap<ValuePair, ValuePair> &ConnectedPairs,
1626 std::multimap<ValuePair, ValuePair> &ConnectedPairDeps,
1627 DenseSet<ValuePair> &PairableInstUsers,
1628 std::multimap<ValuePair, ValuePair> &PairableInstUserMap,
1629 DenseMap<Value *, Value *> &ChosenPairs,
1630 DenseSet<ValuePair> &BestTree, size_t &BestMaxDepth,
1631 int &BestEffSize, VPIteratorPair ChoiceRange,
1632 bool UseCycleCheck) {
1633 for (std::multimap<Value *, Value *>::iterator J = ChoiceRange.first;
1634 J != ChoiceRange.second; ++J) {
1636 // Before going any further, make sure that this pair does not
1637 // conflict with any already-selected pairs (see comment below
1638 // near the Tree pruning for more details).
1639 DenseSet<ValuePair> ChosenPairSet;
1640 bool DoesConflict = false;
1641 for (DenseMap<Value *, Value *>::iterator C = ChosenPairs.begin(),
1642 E = ChosenPairs.end(); C != E; ++C) {
1643 if (pairsConflict(*C, *J, PairableInstUsers,
1644 UseCycleCheck ? &PairableInstUserMap : 0)) {
1645 DoesConflict = true;
1649 ChosenPairSet.insert(*C);
1651 if (DoesConflict) continue;
1653 if (UseCycleCheck &&
1654 pairWillFormCycle(*J, PairableInstUserMap, ChosenPairSet))
1657 DenseMap<ValuePair, size_t> Tree;
1658 buildInitialTreeFor(CandidatePairs, PairableInsts, ConnectedPairs,
1659 PairableInstUsers, ChosenPairs, Tree, *J);
1661 // Because we'll keep the child with the largest depth, the largest
1662 // depth is still the same in the unpruned Tree.
1663 size_t MaxDepth = Tree.lookup(*J);
1665 DEBUG(if (DebugPairSelection) dbgs() << "BBV: found Tree for pair {"
1666 << *J->first << " <-> " << *J->second << "} of depth " <<
1667 MaxDepth << " and size " << Tree.size() << "\n");
1669 // At this point the Tree has been constructed, but, may contain
1670 // contradictory children (meaning that different children of
1671 // some tree node may be attempting to fuse the same instruction).
1672 // So now we walk the tree again, in the case of a conflict,
1673 // keep only the child with the largest depth. To break a tie,
1674 // favor the first child.
1676 DenseSet<ValuePair> PrunedTree;
1677 pruneTreeFor(CandidatePairs, PairableInsts, ConnectedPairs,
1678 PairableInstUsers, PairableInstUserMap, ChosenPairs, Tree,
1679 PrunedTree, *J, UseCycleCheck);
1683 DenseSet<Value *> PrunedTreeInstrs;
1684 for (DenseSet<ValuePair>::iterator S = PrunedTree.begin(),
1685 E = PrunedTree.end(); S != E; ++S) {
1686 PrunedTreeInstrs.insert(S->first);
1687 PrunedTreeInstrs.insert(S->second);
1690 // The set of pairs that have already contributed to the total cost.
1691 DenseSet<ValuePair> IncomingPairs;
1693 // The node weights represent the cost savings associated with
1694 // fusing the pair of instructions.
1695 for (DenseSet<ValuePair>::iterator S = PrunedTree.begin(),
1696 E = PrunedTree.end(); S != E; ++S) {
1697 bool FlipOrder = false;
1699 if (getDepthFactor(S->first)) {
1700 int ESContrib = CandidatePairCostSavings.find(*S)->second;
1701 DEBUG(if (DebugPairSelection) dbgs() << "\tweight {"
1702 << *S->first << " <-> " << *S->second << "} = " <<
1704 EffSize += ESContrib;
1707 // The edge weights contribute in a negative sense: they represent
1708 // the cost of shuffles.
1709 VPPIteratorPair IP = ConnectedPairDeps.equal_range(*S);
1710 if (IP.first != ConnectedPairDeps.end()) {
1711 unsigned NumDepsDirect = 0, NumDepsSwap = 0;
1712 for (std::multimap<ValuePair, ValuePair>::iterator Q = IP.first;
1713 Q != IP.second; ++Q) {
1714 if (!PrunedTree.count(Q->second))
1716 DenseMap<VPPair, unsigned>::iterator R =
1717 PairConnectionTypes.find(VPPair(Q->second, Q->first));
1718 assert(R != PairConnectionTypes.end() &&
1719 "Cannot find pair connection type");
1720 if (R->second == PairConnectionDirect)
1722 else if (R->second == PairConnectionSwap)
1726 // If there are more swaps than direct connections, then
1727 // the pair order will be flipped during fusion. So the real
1728 // number of swaps is the minimum number.
1729 FlipOrder = !FixedOrderPairs.count(*S) &&
1730 ((NumDepsSwap > NumDepsDirect) ||
1731 FixedOrderPairs.count(ValuePair(S->second, S->first)));
1733 for (std::multimap<ValuePair, ValuePair>::iterator Q = IP.first;
1734 Q != IP.second; ++Q) {
1735 if (!PrunedTree.count(Q->second))
1737 DenseMap<VPPair, unsigned>::iterator R =
1738 PairConnectionTypes.find(VPPair(Q->second, Q->first));
1739 assert(R != PairConnectionTypes.end() &&
1740 "Cannot find pair connection type");
1741 Type *Ty1 = Q->second.first->getType(),
1742 *Ty2 = Q->second.second->getType();
1743 Type *VTy = getVecTypeForPair(Ty1, Ty2);
1744 if ((R->second == PairConnectionDirect && FlipOrder) ||
1745 (R->second == PairConnectionSwap && !FlipOrder) ||
1746 R->second == PairConnectionSplat) {
1747 int ESContrib = (int) getInstrCost(Instruction::ShuffleVector,
1749 DEBUG(if (DebugPairSelection) dbgs() << "\tcost {" <<
1750 *Q->second.first << " <-> " << *Q->second.second <<
1752 *S->first << " <-> " << *S->second << "} = " <<
1754 EffSize -= ESContrib;
1759 // Compute the cost of outgoing edges. We assume that edges outgoing
1760 // to shuffles, inserts or extracts can be merged, and so contribute
1761 // no additional cost.
1762 if (!S->first->getType()->isVoidTy()) {
1763 Type *Ty1 = S->first->getType(),
1764 *Ty2 = S->second->getType();
1765 Type *VTy = getVecTypeForPair(Ty1, Ty2);
1767 bool NeedsExtraction = false;
1768 for (Value::use_iterator I = S->first->use_begin(),
1769 IE = S->first->use_end(); I != IE; ++I) {
1770 if (ShuffleVectorInst *SI = dyn_cast<ShuffleVectorInst>(*I)) {
1771 // Shuffle can be folded if it has no other input
1772 if (isa<UndefValue>(SI->getOperand(1)))
1775 if (isa<ExtractElementInst>(*I))
1777 if (PrunedTreeInstrs.count(*I))
1779 NeedsExtraction = true;
1783 if (NeedsExtraction) {
1785 if (Ty1->isVectorTy())
1786 ESContrib = (int) getInstrCost(Instruction::ShuffleVector,
1789 ESContrib = (int) VTTI->getVectorInstrCost(
1790 Instruction::ExtractElement, VTy, 0);
1792 DEBUG(if (DebugPairSelection) dbgs() << "\tcost {" <<
1793 *S->first << "} = " << ESContrib << "\n");
1794 EffSize -= ESContrib;
1797 NeedsExtraction = false;
1798 for (Value::use_iterator I = S->second->use_begin(),
1799 IE = S->second->use_end(); I != IE; ++I) {
1800 if (ShuffleVectorInst *SI = dyn_cast<ShuffleVectorInst>(*I)) {
1801 // Shuffle can be folded if it has no other input
1802 if (isa<UndefValue>(SI->getOperand(1)))
1805 if (isa<ExtractElementInst>(*I))
1807 if (PrunedTreeInstrs.count(*I))
1809 NeedsExtraction = true;
1813 if (NeedsExtraction) {
1815 if (Ty2->isVectorTy())
1816 ESContrib = (int) getInstrCost(Instruction::ShuffleVector,
1819 ESContrib = (int) VTTI->getVectorInstrCost(
1820 Instruction::ExtractElement, VTy, 1);
1821 DEBUG(if (DebugPairSelection) dbgs() << "\tcost {" <<
1822 *S->second << "} = " << ESContrib << "\n");
1823 EffSize -= ESContrib;
1827 // Compute the cost of incoming edges.
1828 if (!isa<LoadInst>(S->first) && !isa<StoreInst>(S->first)) {
1829 Instruction *S1 = cast<Instruction>(S->first),
1830 *S2 = cast<Instruction>(S->second);
1831 for (unsigned o = 0; o < S1->getNumOperands(); ++o) {
1832 Value *O1 = S1->getOperand(o), *O2 = S2->getOperand(o);
1834 // Combining constants into vector constants (or small vector
1835 // constants into larger ones are assumed free).
1836 if (isa<Constant>(O1) && isa<Constant>(O2))
1842 ValuePair VP = ValuePair(O1, O2);
1843 ValuePair VPR = ValuePair(O2, O1);
1845 // Internal edges are not handled here.
1846 if (PrunedTree.count(VP) || PrunedTree.count(VPR))
1849 Type *Ty1 = O1->getType(),
1850 *Ty2 = O2->getType();
1851 Type *VTy = getVecTypeForPair(Ty1, Ty2);
1853 // Combining vector operations of the same type is also assumed
1854 // folded with other operations.
1856 // If both are insert elements, then both can be widened.
1857 if (isa<InsertElementInst>(O1) && isa<InsertElementInst>(O2))
1859 // If both are extract elements, and both have the same input
1860 // type, then they can be replaced with a shuffle
1861 ExtractElementInst *EIO1 = dyn_cast<ExtractElementInst>(O1),
1862 *EIO2 = dyn_cast<ExtractElementInst>(O2);
1864 EIO1->getOperand(0)->getType() ==
1865 EIO2->getOperand(0)->getType())
1867 // If both are a shuffle with equal operand types and only two
1868 // unqiue operands, then they can be replaced with a single
1870 ShuffleVectorInst *SIO1 = dyn_cast<ShuffleVectorInst>(O1),
1871 *SIO2 = dyn_cast<ShuffleVectorInst>(O2);
1873 SIO1->getOperand(0)->getType() ==
1874 SIO2->getOperand(0)->getType()) {
1875 SmallSet<Value *, 4> SIOps;
1876 SIOps.insert(SIO1->getOperand(0));
1877 SIOps.insert(SIO1->getOperand(1));
1878 SIOps.insert(SIO2->getOperand(0));
1879 SIOps.insert(SIO2->getOperand(1));
1880 if (SIOps.size() <= 2)
1886 // This pair has already been formed.
1887 if (IncomingPairs.count(VP)) {
1889 } else if (IncomingPairs.count(VPR)) {
1890 ESContrib = (int) getInstrCost(Instruction::ShuffleVector,
1892 } else if (!Ty1->isVectorTy() && !Ty2->isVectorTy()) {
1893 ESContrib = (int) VTTI->getVectorInstrCost(
1894 Instruction::InsertElement, VTy, 0);
1895 ESContrib += (int) VTTI->getVectorInstrCost(
1896 Instruction::InsertElement, VTy, 1);
1897 } else if (!Ty1->isVectorTy()) {
1898 // O1 needs to be inserted into a vector of size O2, and then
1899 // both need to be shuffled together.
1900 ESContrib = (int) VTTI->getVectorInstrCost(
1901 Instruction::InsertElement, Ty2, 0);
1902 ESContrib += (int) getInstrCost(Instruction::ShuffleVector,
1904 } else if (!Ty2->isVectorTy()) {
1905 // O2 needs to be inserted into a vector of size O1, and then
1906 // both need to be shuffled together.
1907 ESContrib = (int) VTTI->getVectorInstrCost(
1908 Instruction::InsertElement, Ty1, 0);
1909 ESContrib += (int) getInstrCost(Instruction::ShuffleVector,
1912 Type *TyBig = Ty1, *TySmall = Ty2;
1913 if (Ty2->getVectorNumElements() > Ty1->getVectorNumElements())
1914 std::swap(TyBig, TySmall);
1916 ESContrib = (int) getInstrCost(Instruction::ShuffleVector,
1918 if (TyBig != TySmall)
1919 ESContrib += (int) getInstrCost(Instruction::ShuffleVector,
1923 DEBUG(if (DebugPairSelection) dbgs() << "\tcost {"
1924 << *O1 << " <-> " << *O2 << "} = " <<
1926 EffSize -= ESContrib;
1927 IncomingPairs.insert(VP);
1932 for (DenseSet<ValuePair>::iterator S = PrunedTree.begin(),
1933 E = PrunedTree.end(); S != E; ++S)
1934 EffSize += (int) getDepthFactor(S->first);
1937 DEBUG(if (DebugPairSelection)
1938 dbgs() << "BBV: found pruned Tree for pair {"
1939 << *J->first << " <-> " << *J->second << "} of depth " <<
1940 MaxDepth << " and size " << PrunedTree.size() <<
1941 " (effective size: " << EffSize << ")\n");
1942 if (((VTTI && !UseChainDepthWithTI) ||
1943 MaxDepth >= Config.ReqChainDepth) &&
1944 EffSize > 0 && EffSize > BestEffSize) {
1945 BestMaxDepth = MaxDepth;
1946 BestEffSize = EffSize;
1947 BestTree = PrunedTree;
1952 // Given the list of candidate pairs, this function selects those
1953 // that will be fused into vector instructions.
1954 void BBVectorize::choosePairs(
1955 std::multimap<Value *, Value *> &CandidatePairs,
1956 DenseMap<ValuePair, int> &CandidatePairCostSavings,
1957 std::vector<Value *> &PairableInsts,
1958 DenseSet<ValuePair> &FixedOrderPairs,
1959 DenseMap<VPPair, unsigned> &PairConnectionTypes,
1960 std::multimap<ValuePair, ValuePair> &ConnectedPairs,
1961 std::multimap<ValuePair, ValuePair> &ConnectedPairDeps,
1962 DenseSet<ValuePair> &PairableInstUsers,
1963 DenseMap<Value *, Value *>& ChosenPairs) {
1964 bool UseCycleCheck =
1965 CandidatePairs.size() <= Config.MaxCandPairsForCycleCheck;
1966 std::multimap<ValuePair, ValuePair> PairableInstUserMap;
1967 for (std::vector<Value *>::iterator I = PairableInsts.begin(),
1968 E = PairableInsts.end(); I != E; ++I) {
1969 // The number of possible pairings for this variable:
1970 size_t NumChoices = CandidatePairs.count(*I);
1971 if (!NumChoices) continue;
1973 VPIteratorPair ChoiceRange = CandidatePairs.equal_range(*I);
1975 // The best pair to choose and its tree:
1976 size_t BestMaxDepth = 0;
1977 int BestEffSize = 0;
1978 DenseSet<ValuePair> BestTree;
1979 findBestTreeFor(CandidatePairs, CandidatePairCostSavings,
1980 PairableInsts, FixedOrderPairs, PairConnectionTypes,
1981 ConnectedPairs, ConnectedPairDeps,
1982 PairableInstUsers, PairableInstUserMap, ChosenPairs,
1983 BestTree, BestMaxDepth, BestEffSize, ChoiceRange,
1986 // A tree has been chosen (or not) at this point. If no tree was
1987 // chosen, then this instruction, I, cannot be paired (and is no longer
1990 DEBUG(if (BestTree.size() > 0)
1991 dbgs() << "BBV: selected pairs in the best tree for: "
1992 << *cast<Instruction>(*I) << "\n");
1994 for (DenseSet<ValuePair>::iterator S = BestTree.begin(),
1995 SE2 = BestTree.end(); S != SE2; ++S) {
1996 // Insert the members of this tree into the list of chosen pairs.
1997 ChosenPairs.insert(ValuePair(S->first, S->second));
1998 DEBUG(dbgs() << "BBV: selected pair: " << *S->first << " <-> " <<
1999 *S->second << "\n");
2001 // Remove all candidate pairs that have values in the chosen tree.
2002 for (std::multimap<Value *, Value *>::iterator K =
2003 CandidatePairs.begin(); K != CandidatePairs.end();) {
2004 if (K->first == S->first || K->second == S->first ||
2005 K->second == S->second || K->first == S->second) {
2006 // Don't remove the actual pair chosen so that it can be used
2007 // in subsequent tree selections.
2008 if (!(K->first == S->first && K->second == S->second))
2009 CandidatePairs.erase(K++);
2019 DEBUG(dbgs() << "BBV: selected " << ChosenPairs.size() << " pairs.\n");
2022 std::string getReplacementName(Instruction *I, bool IsInput, unsigned o,
2027 return (I->getName() + (IsInput ? ".v.i" : ".v.r") + utostr(o) +
2028 (n > 0 ? "." + utostr(n) : "")).str();
2031 // Returns the value that is to be used as the pointer input to the vector
2032 // instruction that fuses I with J.
2033 Value *BBVectorize::getReplacementPointerInput(LLVMContext& Context,
2034 Instruction *I, Instruction *J, unsigned o) {
2036 unsigned IAlignment, JAlignment, IAddressSpace, JAddressSpace;
2037 int64_t OffsetInElmts;
2039 // Note: the analysis might fail here, that is why the pair order has
2040 // been precomputed (OffsetInElmts must be unused here).
2041 (void) getPairPtrInfo(I, J, IPtr, JPtr, IAlignment, JAlignment,
2042 IAddressSpace, JAddressSpace,
2043 OffsetInElmts, false);
2045 // The pointer value is taken to be the one with the lowest offset.
2048 Type *ArgTypeI = cast<PointerType>(IPtr->getType())->getElementType();
2049 Type *ArgTypeJ = cast<PointerType>(JPtr->getType())->getElementType();
2050 Type *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ);
2051 Type *VArgPtrType = PointerType::get(VArgType,
2052 cast<PointerType>(IPtr->getType())->getAddressSpace());
2053 return new BitCastInst(VPtr, VArgPtrType, getReplacementName(I, true, o),
2054 /* insert before */ I);
2057 void BBVectorize::fillNewShuffleMask(LLVMContext& Context, Instruction *J,
2058 unsigned MaskOffset, unsigned NumInElem,
2059 unsigned NumInElem1, unsigned IdxOffset,
2060 std::vector<Constant*> &Mask) {
2061 unsigned NumElem1 = cast<VectorType>(J->getType())->getNumElements();
2062 for (unsigned v = 0; v < NumElem1; ++v) {
2063 int m = cast<ShuffleVectorInst>(J)->getMaskValue(v);
2065 Mask[v+MaskOffset] = UndefValue::get(Type::getInt32Ty(Context));
2067 unsigned mm = m + (int) IdxOffset;
2068 if (m >= (int) NumInElem1)
2069 mm += (int) NumInElem;
2071 Mask[v+MaskOffset] =
2072 ConstantInt::get(Type::getInt32Ty(Context), mm);
2077 // Returns the value that is to be used as the vector-shuffle mask to the
2078 // vector instruction that fuses I with J.
2079 Value *BBVectorize::getReplacementShuffleMask(LLVMContext& Context,
2080 Instruction *I, Instruction *J) {
2081 // This is the shuffle mask. We need to append the second
2082 // mask to the first, and the numbers need to be adjusted.
2084 Type *ArgTypeI = I->getType();
2085 Type *ArgTypeJ = J->getType();
2086 Type *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ);
2088 unsigned NumElemI = cast<VectorType>(ArgTypeI)->getNumElements();
2090 // Get the total number of elements in the fused vector type.
2091 // By definition, this must equal the number of elements in
2093 unsigned NumElem = cast<VectorType>(VArgType)->getNumElements();
2094 std::vector<Constant*> Mask(NumElem);
2096 Type *OpTypeI = I->getOperand(0)->getType();
2097 unsigned NumInElemI = cast<VectorType>(OpTypeI)->getNumElements();
2098 Type *OpTypeJ = J->getOperand(0)->getType();
2099 unsigned NumInElemJ = cast<VectorType>(OpTypeJ)->getNumElements();
2101 // The fused vector will be:
2102 // -----------------------------------------------------
2103 // | NumInElemI | NumInElemJ | NumInElemI | NumInElemJ |
2104 // -----------------------------------------------------
2105 // from which we'll extract NumElem total elements (where the first NumElemI
2106 // of them come from the mask in I and the remainder come from the mask
2109 // For the mask from the first pair...
2110 fillNewShuffleMask(Context, I, 0, NumInElemJ, NumInElemI,
2113 // For the mask from the second pair...
2114 fillNewShuffleMask(Context, J, NumElemI, NumInElemI, NumInElemJ,
2117 return ConstantVector::get(Mask);
2120 bool BBVectorize::expandIEChain(LLVMContext& Context, Instruction *I,
2121 Instruction *J, unsigned o, Value *&LOp,
2123 Type *ArgTypeL, Type *ArgTypeH,
2124 bool IBeforeJ, unsigned IdxOff) {
2125 bool ExpandedIEChain = false;
2126 if (InsertElementInst *LIE = dyn_cast<InsertElementInst>(LOp)) {
2127 // If we have a pure insertelement chain, then this can be rewritten
2128 // into a chain that directly builds the larger type.
2129 bool PureChain = true;
2130 InsertElementInst *LIENext = LIE;
2132 if (!isa<UndefValue>(LIENext->getOperand(0)) &&
2133 !isa<InsertElementInst>(LIENext->getOperand(0))) {
2138 dyn_cast<InsertElementInst>(LIENext->getOperand(0))));
2141 SmallVector<Value *, 8> VectElemts(numElemL,
2142 UndefValue::get(ArgTypeL->getScalarType()));
2143 InsertElementInst *LIENext = LIE;
2146 cast<ConstantInt>(LIENext->getOperand(2))->getSExtValue();
2147 VectElemts[Idx] = LIENext->getOperand(1);
2149 dyn_cast<InsertElementInst>(LIENext->getOperand(0))));
2152 Value *LIEPrev = UndefValue::get(ArgTypeH);
2153 for (unsigned i = 0; i < numElemL; ++i) {
2154 if (isa<UndefValue>(VectElemts[i])) continue;
2155 LIENext = InsertElementInst::Create(LIEPrev, VectElemts[i],
2156 ConstantInt::get(Type::getInt32Ty(Context),
2158 getReplacementName(IBeforeJ ? I : J,
2160 LIENext->insertBefore(IBeforeJ ? J : I);
2164 LOp = LIENext ? (Value*) LIENext : UndefValue::get(ArgTypeH);
2165 ExpandedIEChain = true;
2169 return ExpandedIEChain;
2172 // Returns the value to be used as the specified operand of the vector
2173 // instruction that fuses I with J.
2174 Value *BBVectorize::getReplacementInput(LLVMContext& Context, Instruction *I,
2175 Instruction *J, unsigned o, bool IBeforeJ) {
2176 Value *CV0 = ConstantInt::get(Type::getInt32Ty(Context), 0);
2177 Value *CV1 = ConstantInt::get(Type::getInt32Ty(Context), 1);
2179 // Compute the fused vector type for this operand
2180 Type *ArgTypeI = I->getOperand(o)->getType();
2181 Type *ArgTypeJ = J->getOperand(o)->getType();
2182 VectorType *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ);
2184 Instruction *L = I, *H = J;
2185 Type *ArgTypeL = ArgTypeI, *ArgTypeH = ArgTypeJ;
2188 if (ArgTypeL->isVectorTy())
2189 numElemL = cast<VectorType>(ArgTypeL)->getNumElements();
2194 if (ArgTypeH->isVectorTy())
2195 numElemH = cast<VectorType>(ArgTypeH)->getNumElements();
2199 Value *LOp = L->getOperand(o);
2200 Value *HOp = H->getOperand(o);
2201 unsigned numElem = VArgType->getNumElements();
2203 // First, we check if we can reuse the "original" vector outputs (if these
2204 // exist). We might need a shuffle.
2205 ExtractElementInst *LEE = dyn_cast<ExtractElementInst>(LOp);
2206 ExtractElementInst *HEE = dyn_cast<ExtractElementInst>(HOp);
2207 ShuffleVectorInst *LSV = dyn_cast<ShuffleVectorInst>(LOp);
2208 ShuffleVectorInst *HSV = dyn_cast<ShuffleVectorInst>(HOp);
2210 // FIXME: If we're fusing shuffle instructions, then we can't apply this
2211 // optimization. The input vectors to the shuffle might be a different
2212 // length from the shuffle outputs. Unfortunately, the replacement
2213 // shuffle mask has already been formed, and the mask entries are sensitive
2214 // to the sizes of the inputs.
2215 bool IsSizeChangeShuffle =
2216 isa<ShuffleVectorInst>(L) &&
2217 (LOp->getType() != L->getType() || HOp->getType() != H->getType());
2219 if ((LEE || LSV) && (HEE || HSV) && !IsSizeChangeShuffle) {
2220 // We can have at most two unique vector inputs.
2221 bool CanUseInputs = true;
2224 I1 = LEE->getOperand(0);
2226 I1 = LSV->getOperand(0);
2227 I2 = LSV->getOperand(1);
2228 if (I2 == I1 || isa<UndefValue>(I2))
2233 Value *I3 = HEE->getOperand(0);
2234 if (!I2 && I3 != I1)
2236 else if (I3 != I1 && I3 != I2)
2237 CanUseInputs = false;
2239 Value *I3 = HSV->getOperand(0);
2240 if (!I2 && I3 != I1)
2242 else if (I3 != I1 && I3 != I2)
2243 CanUseInputs = false;
2246 Value *I4 = HSV->getOperand(1);
2247 if (!isa<UndefValue>(I4)) {
2248 if (!I2 && I4 != I1)
2250 else if (I4 != I1 && I4 != I2)
2251 CanUseInputs = false;
2258 cast<VectorType>(cast<Instruction>(LOp)->getOperand(0)->getType())
2261 cast<VectorType>(cast<Instruction>(HOp)->getOperand(0)->getType())
2264 // We have one or two input vectors. We need to map each index of the
2265 // operands to the index of the original vector.
2266 SmallVector<std::pair<int, int>, 8> II(numElem);
2267 for (unsigned i = 0; i < numElemL; ++i) {
2271 cast<ConstantInt>(LEE->getOperand(1))->getSExtValue();
2272 INum = LEE->getOperand(0) == I1 ? 0 : 1;
2274 Idx = LSV->getMaskValue(i);
2275 if (Idx < (int) LOpElem) {
2276 INum = LSV->getOperand(0) == I1 ? 0 : 1;
2279 INum = LSV->getOperand(1) == I1 ? 0 : 1;
2283 II[i] = std::pair<int, int>(Idx, INum);
2285 for (unsigned i = 0; i < numElemH; ++i) {
2289 cast<ConstantInt>(HEE->getOperand(1))->getSExtValue();
2290 INum = HEE->getOperand(0) == I1 ? 0 : 1;
2292 Idx = HSV->getMaskValue(i);
2293 if (Idx < (int) HOpElem) {
2294 INum = HSV->getOperand(0) == I1 ? 0 : 1;
2297 INum = HSV->getOperand(1) == I1 ? 0 : 1;
2301 II[i + numElemL] = std::pair<int, int>(Idx, INum);
2304 // We now have an array which tells us from which index of which
2305 // input vector each element of the operand comes.
2306 VectorType *I1T = cast<VectorType>(I1->getType());
2307 unsigned I1Elem = I1T->getNumElements();
2310 // In this case there is only one underlying vector input. Check for
2311 // the trivial case where we can use the input directly.
2312 if (I1Elem == numElem) {
2313 bool ElemInOrder = true;
2314 for (unsigned i = 0; i < numElem; ++i) {
2315 if (II[i].first != (int) i && II[i].first != -1) {
2316 ElemInOrder = false;
2325 // A shuffle is needed.
2326 std::vector<Constant *> Mask(numElem);
2327 for (unsigned i = 0; i < numElem; ++i) {
2328 int Idx = II[i].first;
2330 Mask[i] = UndefValue::get(Type::getInt32Ty(Context));
2332 Mask[i] = ConstantInt::get(Type::getInt32Ty(Context), Idx);
2336 new ShuffleVectorInst(I1, UndefValue::get(I1T),
2337 ConstantVector::get(Mask),
2338 getReplacementName(IBeforeJ ? I : J,
2340 S->insertBefore(IBeforeJ ? J : I);
2344 VectorType *I2T = cast<VectorType>(I2->getType());
2345 unsigned I2Elem = I2T->getNumElements();
2347 // This input comes from two distinct vectors. The first step is to
2348 // make sure that both vectors are the same length. If not, the
2349 // smaller one will need to grow before they can be shuffled together.
2350 if (I1Elem < I2Elem) {
2351 std::vector<Constant *> Mask(I2Elem);
2353 for (; v < I1Elem; ++v)
2354 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v);
2355 for (; v < I2Elem; ++v)
2356 Mask[v] = UndefValue::get(Type::getInt32Ty(Context));
2358 Instruction *NewI1 =
2359 new ShuffleVectorInst(I1, UndefValue::get(I1T),
2360 ConstantVector::get(Mask),
2361 getReplacementName(IBeforeJ ? I : J,
2363 NewI1->insertBefore(IBeforeJ ? J : I);
2367 } else if (I1Elem > I2Elem) {
2368 std::vector<Constant *> Mask(I1Elem);
2370 for (; v < I2Elem; ++v)
2371 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v);
2372 for (; v < I1Elem; ++v)
2373 Mask[v] = UndefValue::get(Type::getInt32Ty(Context));
2375 Instruction *NewI2 =
2376 new ShuffleVectorInst(I2, UndefValue::get(I2T),
2377 ConstantVector::get(Mask),
2378 getReplacementName(IBeforeJ ? I : J,
2380 NewI2->insertBefore(IBeforeJ ? J : I);
2386 // Now that both I1 and I2 are the same length we can shuffle them
2387 // together (and use the result).
2388 std::vector<Constant *> Mask(numElem);
2389 for (unsigned v = 0; v < numElem; ++v) {
2390 if (II[v].first == -1) {
2391 Mask[v] = UndefValue::get(Type::getInt32Ty(Context));
2393 int Idx = II[v].first + II[v].second * I1Elem;
2394 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), Idx);
2398 Instruction *NewOp =
2399 new ShuffleVectorInst(I1, I2, ConstantVector::get(Mask),
2400 getReplacementName(IBeforeJ ? I : J, true, o));
2401 NewOp->insertBefore(IBeforeJ ? J : I);
2406 Type *ArgType = ArgTypeL;
2407 if (numElemL < numElemH) {
2408 if (numElemL == 1 && expandIEChain(Context, I, J, o, HOp, numElemH,
2409 ArgTypeL, VArgType, IBeforeJ, 1)) {
2410 // This is another short-circuit case: we're combining a scalar into
2411 // a vector that is formed by an IE chain. We've just expanded the IE
2412 // chain, now insert the scalar and we're done.
2414 Instruction *S = InsertElementInst::Create(HOp, LOp, CV0,
2415 getReplacementName(IBeforeJ ? I : J, true, o));
2416 S->insertBefore(IBeforeJ ? J : I);
2418 } else if (!expandIEChain(Context, I, J, o, LOp, numElemL, ArgTypeL,
2419 ArgTypeH, IBeforeJ)) {
2420 // The two vector inputs to the shuffle must be the same length,
2421 // so extend the smaller vector to be the same length as the larger one.
2425 std::vector<Constant *> Mask(numElemH);
2427 for (; v < numElemL; ++v)
2428 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v);
2429 for (; v < numElemH; ++v)
2430 Mask[v] = UndefValue::get(Type::getInt32Ty(Context));
2432 NLOp = new ShuffleVectorInst(LOp, UndefValue::get(ArgTypeL),
2433 ConstantVector::get(Mask),
2434 getReplacementName(IBeforeJ ? I : J,
2437 NLOp = InsertElementInst::Create(UndefValue::get(ArgTypeH), LOp, CV0,
2438 getReplacementName(IBeforeJ ? I : J,
2442 NLOp->insertBefore(IBeforeJ ? J : I);
2447 } else if (numElemL > numElemH) {
2448 if (numElemH == 1 && expandIEChain(Context, I, J, o, LOp, numElemL,
2449 ArgTypeH, VArgType, IBeforeJ)) {
2451 InsertElementInst::Create(LOp, HOp,
2452 ConstantInt::get(Type::getInt32Ty(Context),
2454 getReplacementName(IBeforeJ ? I : J,
2456 S->insertBefore(IBeforeJ ? J : I);
2458 } else if (!expandIEChain(Context, I, J, o, HOp, numElemH, ArgTypeH,
2459 ArgTypeL, IBeforeJ)) {
2462 std::vector<Constant *> Mask(numElemL);
2464 for (; v < numElemH; ++v)
2465 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v);
2466 for (; v < numElemL; ++v)
2467 Mask[v] = UndefValue::get(Type::getInt32Ty(Context));
2469 NHOp = new ShuffleVectorInst(HOp, UndefValue::get(ArgTypeH),
2470 ConstantVector::get(Mask),
2471 getReplacementName(IBeforeJ ? I : J,
2474 NHOp = InsertElementInst::Create(UndefValue::get(ArgTypeL), HOp, CV0,
2475 getReplacementName(IBeforeJ ? I : J,
2479 NHOp->insertBefore(IBeforeJ ? J : I);
2484 if (ArgType->isVectorTy()) {
2485 unsigned numElem = cast<VectorType>(VArgType)->getNumElements();
2486 std::vector<Constant*> Mask(numElem);
2487 for (unsigned v = 0; v < numElem; ++v) {
2489 // If the low vector was expanded, we need to skip the extra
2490 // undefined entries.
2491 if (v >= numElemL && numElemH > numElemL)
2492 Idx += (numElemH - numElemL);
2493 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), Idx);
2496 Instruction *BV = new ShuffleVectorInst(LOp, HOp,
2497 ConstantVector::get(Mask),
2498 getReplacementName(IBeforeJ ? I : J, true, o));
2499 BV->insertBefore(IBeforeJ ? J : I);
2503 Instruction *BV1 = InsertElementInst::Create(
2504 UndefValue::get(VArgType), LOp, CV0,
2505 getReplacementName(IBeforeJ ? I : J,
2507 BV1->insertBefore(IBeforeJ ? J : I);
2508 Instruction *BV2 = InsertElementInst::Create(BV1, HOp, CV1,
2509 getReplacementName(IBeforeJ ? I : J,
2511 BV2->insertBefore(IBeforeJ ? J : I);
2515 // This function creates an array of values that will be used as the inputs
2516 // to the vector instruction that fuses I with J.
2517 void BBVectorize::getReplacementInputsForPair(LLVMContext& Context,
2518 Instruction *I, Instruction *J,
2519 SmallVector<Value *, 3> &ReplacedOperands,
2521 unsigned NumOperands = I->getNumOperands();
2523 for (unsigned p = 0, o = NumOperands-1; p < NumOperands; ++p, --o) {
2524 // Iterate backward so that we look at the store pointer
2525 // first and know whether or not we need to flip the inputs.
2527 if (isa<LoadInst>(I) || (o == 1 && isa<StoreInst>(I))) {
2528 // This is the pointer for a load/store instruction.
2529 ReplacedOperands[o] = getReplacementPointerInput(Context, I, J, o);
2531 } else if (isa<CallInst>(I)) {
2532 Function *F = cast<CallInst>(I)->getCalledFunction();
2533 unsigned IID = F->getIntrinsicID();
2534 if (o == NumOperands-1) {
2535 BasicBlock &BB = *I->getParent();
2537 Module *M = BB.getParent()->getParent();
2538 Type *ArgTypeI = I->getType();
2539 Type *ArgTypeJ = J->getType();
2540 Type *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ);
2542 ReplacedOperands[o] = Intrinsic::getDeclaration(M,
2543 (Intrinsic::ID) IID, VArgType);
2545 } else if (IID == Intrinsic::powi && o == 1) {
2546 // The second argument of powi is a single integer and we've already
2547 // checked that both arguments are equal. As a result, we just keep
2548 // I's second argument.
2549 ReplacedOperands[o] = I->getOperand(o);
2552 } else if (isa<ShuffleVectorInst>(I) && o == NumOperands-1) {
2553 ReplacedOperands[o] = getReplacementShuffleMask(Context, I, J);
2557 ReplacedOperands[o] = getReplacementInput(Context, I, J, o, IBeforeJ);
2561 // This function creates two values that represent the outputs of the
2562 // original I and J instructions. These are generally vector shuffles
2563 // or extracts. In many cases, these will end up being unused and, thus,
2564 // eliminated by later passes.
2565 void BBVectorize::replaceOutputsOfPair(LLVMContext& Context, Instruction *I,
2566 Instruction *J, Instruction *K,
2567 Instruction *&InsertionPt,
2568 Instruction *&K1, Instruction *&K2) {
2569 if (isa<StoreInst>(I)) {
2570 AA->replaceWithNewValue(I, K);
2571 AA->replaceWithNewValue(J, K);
2573 Type *IType = I->getType();
2574 Type *JType = J->getType();
2576 VectorType *VType = getVecTypeForPair(IType, JType);
2577 unsigned numElem = VType->getNumElements();
2579 unsigned numElemI, numElemJ;
2580 if (IType->isVectorTy())
2581 numElemI = cast<VectorType>(IType)->getNumElements();
2585 if (JType->isVectorTy())
2586 numElemJ = cast<VectorType>(JType)->getNumElements();
2590 if (IType->isVectorTy()) {
2591 std::vector<Constant*> Mask1(numElemI), Mask2(numElemI);
2592 for (unsigned v = 0; v < numElemI; ++v) {
2593 Mask1[v] = ConstantInt::get(Type::getInt32Ty(Context), v);
2594 Mask2[v] = ConstantInt::get(Type::getInt32Ty(Context), numElemJ+v);
2597 K1 = new ShuffleVectorInst(K, UndefValue::get(VType),
2598 ConstantVector::get( Mask1),
2599 getReplacementName(K, false, 1));
2601 Value *CV0 = ConstantInt::get(Type::getInt32Ty(Context), 0);
2602 K1 = ExtractElementInst::Create(K, CV0,
2603 getReplacementName(K, false, 1));
2606 if (JType->isVectorTy()) {
2607 std::vector<Constant*> Mask1(numElemJ), Mask2(numElemJ);
2608 for (unsigned v = 0; v < numElemJ; ++v) {
2609 Mask1[v] = ConstantInt::get(Type::getInt32Ty(Context), v);
2610 Mask2[v] = ConstantInt::get(Type::getInt32Ty(Context), numElemI+v);
2613 K2 = new ShuffleVectorInst(K, UndefValue::get(VType),
2614 ConstantVector::get( Mask2),
2615 getReplacementName(K, false, 2));
2617 Value *CV1 = ConstantInt::get(Type::getInt32Ty(Context), numElem-1);
2618 K2 = ExtractElementInst::Create(K, CV1,
2619 getReplacementName(K, false, 2));
2623 K2->insertAfter(K1);
2628 // Move all uses of the function I (including pairing-induced uses) after J.
2629 bool BBVectorize::canMoveUsesOfIAfterJ(BasicBlock &BB,
2630 std::multimap<Value *, Value *> &LoadMoveSet,
2631 Instruction *I, Instruction *J) {
2632 // Skip to the first instruction past I.
2633 BasicBlock::iterator L = llvm::next(BasicBlock::iterator(I));
2635 DenseSet<Value *> Users;
2636 AliasSetTracker WriteSet(*AA);
2637 for (; cast<Instruction>(L) != J; ++L)
2638 (void) trackUsesOfI(Users, WriteSet, I, L, true, &LoadMoveSet);
2640 assert(cast<Instruction>(L) == J &&
2641 "Tracking has not proceeded far enough to check for dependencies");
2642 // If J is now in the use set of I, then trackUsesOfI will return true
2643 // and we have a dependency cycle (and the fusing operation must abort).
2644 return !trackUsesOfI(Users, WriteSet, I, J, true, &LoadMoveSet);
2647 // Move all uses of the function I (including pairing-induced uses) after J.
2648 void BBVectorize::moveUsesOfIAfterJ(BasicBlock &BB,
2649 std::multimap<Value *, Value *> &LoadMoveSet,
2650 Instruction *&InsertionPt,
2651 Instruction *I, Instruction *J) {
2652 // Skip to the first instruction past I.
2653 BasicBlock::iterator L = llvm::next(BasicBlock::iterator(I));
2655 DenseSet<Value *> Users;
2656 AliasSetTracker WriteSet(*AA);
2657 for (; cast<Instruction>(L) != J;) {
2658 if (trackUsesOfI(Users, WriteSet, I, L, true, &LoadMoveSet)) {
2659 // Move this instruction
2660 Instruction *InstToMove = L; ++L;
2662 DEBUG(dbgs() << "BBV: moving: " << *InstToMove <<
2663 " to after " << *InsertionPt << "\n");
2664 InstToMove->removeFromParent();
2665 InstToMove->insertAfter(InsertionPt);
2666 InsertionPt = InstToMove;
2673 // Collect all load instruction that are in the move set of a given first
2674 // pair member. These loads depend on the first instruction, I, and so need
2675 // to be moved after J (the second instruction) when the pair is fused.
2676 void BBVectorize::collectPairLoadMoveSet(BasicBlock &BB,
2677 DenseMap<Value *, Value *> &ChosenPairs,
2678 std::multimap<Value *, Value *> &LoadMoveSet,
2680 // Skip to the first instruction past I.
2681 BasicBlock::iterator L = llvm::next(BasicBlock::iterator(I));
2683 DenseSet<Value *> Users;
2684 AliasSetTracker WriteSet(*AA);
2686 // Note: We cannot end the loop when we reach J because J could be moved
2687 // farther down the use chain by another instruction pairing. Also, J
2688 // could be before I if this is an inverted input.
2689 for (BasicBlock::iterator E = BB.end(); cast<Instruction>(L) != E; ++L) {
2690 if (trackUsesOfI(Users, WriteSet, I, L)) {
2691 if (L->mayReadFromMemory())
2692 LoadMoveSet.insert(ValuePair(L, I));
2697 // In cases where both load/stores and the computation of their pointers
2698 // are chosen for vectorization, we can end up in a situation where the
2699 // aliasing analysis starts returning different query results as the
2700 // process of fusing instruction pairs continues. Because the algorithm
2701 // relies on finding the same use trees here as were found earlier, we'll
2702 // need to precompute the necessary aliasing information here and then
2703 // manually update it during the fusion process.
2704 void BBVectorize::collectLoadMoveSet(BasicBlock &BB,
2705 std::vector<Value *> &PairableInsts,
2706 DenseMap<Value *, Value *> &ChosenPairs,
2707 std::multimap<Value *, Value *> &LoadMoveSet) {
2708 for (std::vector<Value *>::iterator PI = PairableInsts.begin(),
2709 PIE = PairableInsts.end(); PI != PIE; ++PI) {
2710 DenseMap<Value *, Value *>::iterator P = ChosenPairs.find(*PI);
2711 if (P == ChosenPairs.end()) continue;
2713 Instruction *I = cast<Instruction>(P->first);
2714 collectPairLoadMoveSet(BB, ChosenPairs, LoadMoveSet, I);
2718 // When the first instruction in each pair is cloned, it will inherit its
2719 // parent's metadata. This metadata must be combined with that of the other
2720 // instruction in a safe way.
2721 void BBVectorize::combineMetadata(Instruction *K, const Instruction *J) {
2722 SmallVector<std::pair<unsigned, MDNode*>, 4> Metadata;
2723 K->getAllMetadataOtherThanDebugLoc(Metadata);
2724 for (unsigned i = 0, n = Metadata.size(); i < n; ++i) {
2725 unsigned Kind = Metadata[i].first;
2726 MDNode *JMD = J->getMetadata(Kind);
2727 MDNode *KMD = Metadata[i].second;
2731 K->setMetadata(Kind, 0); // Remove unknown metadata
2733 case LLVMContext::MD_tbaa:
2734 K->setMetadata(Kind, MDNode::getMostGenericTBAA(JMD, KMD));
2736 case LLVMContext::MD_fpmath:
2737 K->setMetadata(Kind, MDNode::getMostGenericFPMath(JMD, KMD));
2743 // This function fuses the chosen instruction pairs into vector instructions,
2744 // taking care preserve any needed scalar outputs and, then, it reorders the
2745 // remaining instructions as needed (users of the first member of the pair
2746 // need to be moved to after the location of the second member of the pair
2747 // because the vector instruction is inserted in the location of the pair's
2749 void BBVectorize::fuseChosenPairs(BasicBlock &BB,
2750 std::vector<Value *> &PairableInsts,
2751 DenseMap<Value *, Value *> &ChosenPairs,
2752 DenseSet<ValuePair> &FixedOrderPairs,
2753 DenseMap<VPPair, unsigned> &PairConnectionTypes,
2754 std::multimap<ValuePair, ValuePair> &ConnectedPairs,
2755 std::multimap<ValuePair, ValuePair> &ConnectedPairDeps) {
2756 LLVMContext& Context = BB.getContext();
2758 // During the vectorization process, the order of the pairs to be fused
2759 // could be flipped. So we'll add each pair, flipped, into the ChosenPairs
2760 // list. After a pair is fused, the flipped pair is removed from the list.
2761 DenseSet<ValuePair> FlippedPairs;
2762 for (DenseMap<Value *, Value *>::iterator P = ChosenPairs.begin(),
2763 E = ChosenPairs.end(); P != E; ++P)
2764 FlippedPairs.insert(ValuePair(P->second, P->first));
2765 for (DenseSet<ValuePair>::iterator P = FlippedPairs.begin(),
2766 E = FlippedPairs.end(); P != E; ++P)
2767 ChosenPairs.insert(*P);
2769 std::multimap<Value *, Value *> LoadMoveSet;
2770 collectLoadMoveSet(BB, PairableInsts, ChosenPairs, LoadMoveSet);
2772 DEBUG(dbgs() << "BBV: initial: \n" << BB << "\n");
2774 for (BasicBlock::iterator PI = BB.getFirstInsertionPt(); PI != BB.end();) {
2775 DenseMap<Value *, Value *>::iterator P = ChosenPairs.find(PI);
2776 if (P == ChosenPairs.end()) {
2781 if (getDepthFactor(P->first) == 0) {
2782 // These instructions are not really fused, but are tracked as though
2783 // they are. Any case in which it would be interesting to fuse them
2784 // will be taken care of by InstCombine.
2790 Instruction *I = cast<Instruction>(P->first),
2791 *J = cast<Instruction>(P->second);
2793 DEBUG(dbgs() << "BBV: fusing: " << *I <<
2794 " <-> " << *J << "\n");
2796 // Remove the pair and flipped pair from the list.
2797 DenseMap<Value *, Value *>::iterator FP = ChosenPairs.find(P->second);
2798 assert(FP != ChosenPairs.end() && "Flipped pair not found in list");
2799 ChosenPairs.erase(FP);
2800 ChosenPairs.erase(P);
2802 if (!canMoveUsesOfIAfterJ(BB, LoadMoveSet, I, J)) {
2803 DEBUG(dbgs() << "BBV: fusion of: " << *I <<
2805 " aborted because of non-trivial dependency cycle\n");
2811 // If the pair must have the other order, then flip it.
2812 bool FlipPairOrder = FixedOrderPairs.count(ValuePair(J, I));
2813 if (!FlipPairOrder && !FixedOrderPairs.count(ValuePair(I, J))) {
2814 // This pair does not have a fixed order, and so we might want to
2815 // flip it if that will yield fewer shuffles. We count the number
2816 // of dependencies connected via swaps, and those directly connected,
2817 // and flip the order if the number of swaps is greater.
2818 bool OrigOrder = true;
2819 VPPIteratorPair IP = ConnectedPairDeps.equal_range(ValuePair(I, J));
2820 if (IP.first == ConnectedPairDeps.end()) {
2821 IP = ConnectedPairDeps.equal_range(ValuePair(J, I));
2825 if (IP.first != ConnectedPairDeps.end()) {
2826 unsigned NumDepsDirect = 0, NumDepsSwap = 0;
2827 for (std::multimap<ValuePair, ValuePair>::iterator Q = IP.first;
2828 Q != IP.second; ++Q) {
2829 DenseMap<VPPair, unsigned>::iterator R =
2830 PairConnectionTypes.find(VPPair(Q->second, Q->first));
2831 assert(R != PairConnectionTypes.end() &&
2832 "Cannot find pair connection type");
2833 if (R->second == PairConnectionDirect)
2835 else if (R->second == PairConnectionSwap)
2840 std::swap(NumDepsDirect, NumDepsSwap);
2842 if (NumDepsSwap > NumDepsDirect) {
2843 FlipPairOrder = true;
2844 DEBUG(dbgs() << "BBV: reordering pair: " << *I <<
2845 " <-> " << *J << "\n");
2850 Instruction *L = I, *H = J;
2854 // If the pair being fused uses the opposite order from that in the pair
2855 // connection map, then we need to flip the types.
2856 VPPIteratorPair IP = ConnectedPairs.equal_range(ValuePair(H, L));
2857 for (std::multimap<ValuePair, ValuePair>::iterator Q = IP.first;
2858 Q != IP.second; ++Q) {
2859 DenseMap<VPPair, unsigned>::iterator R = PairConnectionTypes.find(*Q);
2860 assert(R != PairConnectionTypes.end() &&
2861 "Cannot find pair connection type");
2862 if (R->second == PairConnectionDirect)
2863 R->second = PairConnectionSwap;
2864 else if (R->second == PairConnectionSwap)
2865 R->second = PairConnectionDirect;
2868 bool LBeforeH = !FlipPairOrder;
2869 unsigned NumOperands = I->getNumOperands();
2870 SmallVector<Value *, 3> ReplacedOperands(NumOperands);
2871 getReplacementInputsForPair(Context, L, H, ReplacedOperands,
2874 // Make a copy of the original operation, change its type to the vector
2875 // type and replace its operands with the vector operands.
2876 Instruction *K = L->clone();
2879 else if (H->hasName())
2882 if (!isa<StoreInst>(K))
2883 K->mutateType(getVecTypeForPair(L->getType(), H->getType()));
2885 combineMetadata(K, H);
2887 for (unsigned o = 0; o < NumOperands; ++o)
2888 K->setOperand(o, ReplacedOperands[o]);
2892 // Instruction insertion point:
2893 Instruction *InsertionPt = K;
2894 Instruction *K1 = 0, *K2 = 0;
2895 replaceOutputsOfPair(Context, L, H, K, InsertionPt, K1, K2);
2897 // The use tree of the first original instruction must be moved to after
2898 // the location of the second instruction. The entire use tree of the
2899 // first instruction is disjoint from the input tree of the second
2900 // (by definition), and so commutes with it.
2902 moveUsesOfIAfterJ(BB, LoadMoveSet, InsertionPt, I, J);
2904 if (!isa<StoreInst>(I)) {
2905 L->replaceAllUsesWith(K1);
2906 H->replaceAllUsesWith(K2);
2907 AA->replaceWithNewValue(L, K1);
2908 AA->replaceWithNewValue(H, K2);
2911 // Instructions that may read from memory may be in the load move set.
2912 // Once an instruction is fused, we no longer need its move set, and so
2913 // the values of the map never need to be updated. However, when a load
2914 // is fused, we need to merge the entries from both instructions in the
2915 // pair in case those instructions were in the move set of some other
2916 // yet-to-be-fused pair. The loads in question are the keys of the map.
2917 if (I->mayReadFromMemory()) {
2918 std::vector<ValuePair> NewSetMembers;
2919 VPIteratorPair IPairRange = LoadMoveSet.equal_range(I);
2920 VPIteratorPair JPairRange = LoadMoveSet.equal_range(J);
2921 for (std::multimap<Value *, Value *>::iterator N = IPairRange.first;
2922 N != IPairRange.second; ++N)
2923 NewSetMembers.push_back(ValuePair(K, N->second));
2924 for (std::multimap<Value *, Value *>::iterator N = JPairRange.first;
2925 N != JPairRange.second; ++N)
2926 NewSetMembers.push_back(ValuePair(K, N->second));
2927 for (std::vector<ValuePair>::iterator A = NewSetMembers.begin(),
2928 AE = NewSetMembers.end(); A != AE; ++A)
2929 LoadMoveSet.insert(*A);
2932 // Before removing I, set the iterator to the next instruction.
2933 PI = llvm::next(BasicBlock::iterator(I));
2934 if (cast<Instruction>(PI) == J)
2939 I->eraseFromParent();
2940 J->eraseFromParent();
2942 DEBUG(if (PrintAfterEveryPair) dbgs() << "BBV: block is now: \n" <<
2946 DEBUG(dbgs() << "BBV: final: \n" << BB << "\n");
2950 char BBVectorize::ID = 0;
2951 static const char bb_vectorize_name[] = "Basic-Block Vectorization";
2952 INITIALIZE_PASS_BEGIN(BBVectorize, BBV_NAME, bb_vectorize_name, false, false)
2953 INITIALIZE_AG_DEPENDENCY(AliasAnalysis)
2954 INITIALIZE_PASS_DEPENDENCY(DominatorTree)
2955 INITIALIZE_PASS_DEPENDENCY(ScalarEvolution)
2956 INITIALIZE_PASS_END(BBVectorize, BBV_NAME, bb_vectorize_name, false, false)
2958 BasicBlockPass *llvm::createBBVectorizePass(const VectorizeConfig &C) {
2959 return new BBVectorize(C);
2963 llvm::vectorizeBasicBlock(Pass *P, BasicBlock &BB, const VectorizeConfig &C) {
2964 BBVectorize BBVectorizer(P, C);
2965 return BBVectorizer.vectorizeBB(BB);
2968 //===----------------------------------------------------------------------===//
2969 VectorizeConfig::VectorizeConfig() {
2970 VectorBits = ::VectorBits;
2971 VectorizeBools = !::NoBools;
2972 VectorizeInts = !::NoInts;
2973 VectorizeFloats = !::NoFloats;
2974 VectorizePointers = !::NoPointers;
2975 VectorizeCasts = !::NoCasts;
2976 VectorizeMath = !::NoMath;
2977 VectorizeFMA = !::NoFMA;
2978 VectorizeSelect = !::NoSelect;
2979 VectorizeCmp = !::NoCmp;
2980 VectorizeGEP = !::NoGEP;
2981 VectorizeMemOps = !::NoMemOps;
2982 AlignedOnly = ::AlignedOnly;
2983 ReqChainDepth= ::ReqChainDepth;
2984 SearchLimit = ::SearchLimit;
2985 MaxCandPairsForCycleCheck = ::MaxCandPairsForCycleCheck;
2986 SplatBreaksChain = ::SplatBreaksChain;
2987 MaxInsts = ::MaxInsts;
2988 MaxIter = ::MaxIter;
2989 Pow2LenOnly = ::Pow2LenOnly;
2990 NoMemOpBoost = ::NoMemOpBoost;
2991 FastDep = ::FastDep;