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lib/Transforms/Vectorize/LoopVectorize.cpp

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49#include "llvm/ADT/MapVector.h" 49​#include "llvm/ADT/MapVector.h"
50#include "llvm/ADT/SetVector.h" 50​#include "llvm/ADT/SetVector.h"
51#include "llvm/ADT/SmallPtrSet.h" 51​#include "llvm/ADT/SmallPtrSet.h"
52#include "llvm/ADT/SmallSet.h" 52​#include "llvm/ADT/SmallSet.h"
53#include "llvm/ADT/SmallVector.h" 53​#include "llvm/ADT/SmallVector.h"
54#include "llvm/ADT/Statistic.h" 54​#include "llvm/ADT/Statistic.h"
55#include "llvm/ADT/StringExtras.h" 55​#include "llvm/ADT/StringExtras.h"
56#include "llvm/Analysis/AliasAnalysis.h" 56​#include "llvm/Analysis/AliasAnalysis.h"
57​#include "llvm/Analysis/AliasSetTracker.h"
57#include "llvm/Analysis/BlockFrequencyInfo.h" 58​#include "llvm/Analysis/BlockFrequencyInfo.h"
58#include "llvm/Analysis/LoopInfo.h" 59​#include "llvm/Analysis/LoopInfo.h"
59#include "llvm/Analysis/LoopIterator.h" 60​#include "llvm/Analysis/LoopIterator.h"
60#include "llvm/Analysis/LoopPass.h" 61​#include "llvm/Analysis/LoopPass.h"
61#include "llvm/Analysis/ScalarEvolution.h" 62​#include "llvm/Analysis/ScalarEvolution.h"
62#include "llvm/Analysis/ScalarEvolutionExpander.h" 63​#include "llvm/Analysis/ScalarEvolutionExpander.h"
63#include "llvm/Analysis/ScalarEvolutionExpressions.h" 64​#include "llvm/Analysis/ScalarEvolutionExpressions.h"
64#include "llvm/Analysis/TargetTransformInfo.h" 65​#include "llvm/Analysis/TargetTransformInfo.h"
▲ Show 20 Lines • Show All 339 Lines • ▼ Show 20 Line(s)275protected:
404 /// The original loop. 405​ /// The original loop.
405 Loop *OrigLoop; 406​ Loop *OrigLoop;
406 /// Scev analysis to use. 407​ /// Scev analysis to use.
407 ScalarEvolution *SE; 408​ ScalarEvolution *SE;
408 /// Loop Info. 409​ /// Loop Info.
409 LoopInfo *LI; 410​ LoopInfo *LI;
410 /// Dominator Tree. 411​ /// Dominator Tree.
411 DominatorTree *DT; 412​ DominatorTree *DT;
413​ /// Alias Analysis.
414​ AliasAnalysis *AA;
412 /// Data Layout. 415​ /// Data Layout.
413 const DataLayout *DL; 416​ const DataLayout *DL;
414 /// Target Library Info. 417​ /// Target Library Info.
415 const TargetLibraryInfo *TLI; 418​ const TargetLibraryInfo *TLI;
416 419​
417 /// The vectorization SIMD factor to use. Each vector will have this many 420​ /// The vectorization SIMD factor to use. Each vector will have this many
418 /// vector elements. 421​ /// vector elements.
419 unsigned VF; 422​ unsigned VF;
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562class LoopVectorizationLegality { 565​class LoopVectorizationLegality {
563public: 566​public:
564 unsigned NumLoads; 567​ unsigned NumLoads;
565 unsigned NumStores; 568​ unsigned NumStores;
566 unsigned NumPredStores; 569​ unsigned NumPredStores;
567 570​
568 LoopVectorizationLegality(Loop *L, ScalarEvolution *SE, const DataLayout *DL, 571​ LoopVectorizationLegality(Loop *L, ScalarEvolution *SE, const DataLayout *DL,
569 DominatorTree *DT, TargetLibraryInfo *TLI, 572​ DominatorTree *DT, TargetLibraryInfo *TLI,
570 Function *F) 573​ AliasAnalysis *AA, Function *F)
571 : NumLoads(0), NumStores(0), NumPredStores(0), TheLoop(L), SE(SE), DL(DL), 574​ : NumLoads(0), NumStores(0), NumPredStores(0), TheLoop(L), SE(SE), DL(DL),
572 DT(DT), TLI(TLI), TheFunction(F), Induction(nullptr), 575​ DT(DT), TLI(TLI), AA(AA), TheFunction(F), Induction(nullptr),
573 WidestIndTy(nullptr), HasFunNoNaNAttr(false), MaxSafeDepDistBytes(-1U) { 576​ WidestIndTy(nullptr), HasFunNoNaNAttr(false), MaxSafeDepDistBytes(-1U) {
574 } 577​ }
575 578​
576 /// This enum represents the kinds of reductions that we support. 579​ /// This enum represents the kinds of reductions that we support.
577 enum ReductionKind { 580​ enum ReductionKind {
578 RK_NoReduction, ///< Not a reduction. 581​ RK_NoReduction, ///< Not a reduction.
579 RK_IntegerAdd, ///< Sum of integers. 582​ RK_IntegerAdd, ///< Sum of integers.
580 RK_IntegerMult, ///< Product of integers. 583​ RK_IntegerMult, ///< Product of integers.
▲ Show 20 Lines • Show All 71 Lines • ▼ Show 20 Line(s)652 struct RuntimePointerCheck {
652 /// Reset the state of the pointer runtime information. 655​ /// Reset the state of the pointer runtime information.
653 void reset() { 656​ void reset() {
654 Need = false; 657​ Need = false;
655 Pointers.clear(); 658​ Pointers.clear();
656 Starts.clear(); 659​ Starts.clear();
657 Ends.clear(); 660​ Ends.clear();
658 IsWritePtr.clear(); 661​ IsWritePtr.clear();
659 DependencySetId.clear(); 662​ DependencySetId.clear();
663​ AliasSetId.clear();
660 } 664​ }
661 665​
662 /// Insert a pointer and calculate the start and end SCEVs. 666​ /// Insert a pointer and calculate the start and end SCEVs.
663 void insert(ScalarEvolution *SE, Loop *Lp, Value *Ptr, bool WritePtr, 667​ void insert(ScalarEvolution *SE, Loop *Lp, Value *Ptr, bool WritePtr,
664 unsigned DepSetId, ValueToValueMap &Strides); 668​ unsigned DepSetId, unsigned ASId, ValueToValueMap &Strides);
665 669​
666 /// This flag indicates if we need to add the runtime check. 670​ /// This flag indicates if we need to add the runtime check.
667 bool Need; 671​ bool Need;
668 /// Holds the pointers that we need to check. 672​ /// Holds the pointers that we need to check.
669 SmallVector<TrackingVH<Value>, 2> Pointers; 673​ SmallVector<TrackingVH<Value>, 2> Pointers;
670 /// Holds the pointer value at the beginning of the loop. 674​ /// Holds the pointer value at the beginning of the loop.
671 SmallVector<const SCEV*, 2> Starts; 675​ SmallVector<const SCEV*, 2> Starts;
672 /// Holds the pointer value at the end of the loop. 676​ /// Holds the pointer value at the end of the loop.
673 SmallVector<const SCEV*, 2> Ends; 677​ SmallVector<const SCEV*, 2> Ends;
674 /// Holds the information if this pointer is used for writing to memory. 678​ /// Holds the information if this pointer is used for writing to memory.
675 SmallVector<bool, 2> IsWritePtr; 679​ SmallVector<bool, 2> IsWritePtr;
676 /// Holds the id of the set of pointers that could be dependent because of a 680​ /// Holds the id of the set of pointers that could be dependent because of a
677 /// shared underlying object. 681​ /// shared underlying object.
678 SmallVector<unsigned, 2> DependencySetId; 682​ SmallVector<unsigned, 2> DependencySetId;
683​ /// Holds the id of the disjoint alias set to which this pointer belongs.
684​ SmallVector<unsigned, 2> AliasSetId;
679 }; 685​ };
680 686​
681 /// A struct for saving information about induction variables. 687​ /// A struct for saving information about induction variables.
682 struct InductionInfo { 688​ struct InductionInfo {
683 InductionInfo(Value *Start, InductionKind K) : StartValue(Start), IK(K) {} 689​ InductionInfo(Value *Start, InductionKind K) : StartValue(Start), IK(K) {}
684 InductionInfo() : StartValue(nullptr), IK(IK_NoInduction) {} 690​ InductionInfo() : StartValue(nullptr), IK(IK_NoInduction) {}
685 /// Start value. 691​ /// Start value.
686 TrackingVH<Value> StartValue; 692​ TrackingVH<Value> StartValue;
▲ Show 20 Lines • Show All 128 Lines • ▼ Show 20 Line(s)761private:
815 /// Scev analysis. 821​ /// Scev analysis.
816 ScalarEvolution *SE; 822​ ScalarEvolution *SE;
817 /// DataLayout analysis. 823​ /// DataLayout analysis.
818 const DataLayout *DL; 824​ const DataLayout *DL;
819 /// Dominators. 825​ /// Dominators.
820 DominatorTree *DT; 826​ DominatorTree *DT;
821 /// Target Library Info. 827​ /// Target Library Info.
822 TargetLibraryInfo *TLI; 828​ TargetLibraryInfo *TLI;
829​ /// Alias analysis.
830​ AliasAnalysis *AA;
823 /// Parent function 831​ /// Parent function
824 Function *TheFunction; 832​ Function *TheFunction;
825 833​
826 // --- vectorization state --- // 834​ // --- vectorization state --- //
827 835​
828 /// Holds the integer induction variable. This is the counter of the 836​ /// Holds the integer induction variable. This is the counter of the
829 /// loop. 837​ /// loop.
830 PHINode *Induction; 838​ PHINode *Induction;
▲ Show 20 Lines • Show All 322 Lines • ▼ Show 20 Line(s)1151struct LoopVectorize : public FunctionPass {
1153 1161​
1154 ScalarEvolution *SE; 1162​ ScalarEvolution *SE;
1155 const DataLayout *DL; 1163​ const DataLayout *DL;
1156 LoopInfo *LI; 1164​ LoopInfo *LI;
1157 TargetTransformInfo *TTI; 1165​ TargetTransformInfo *TTI;
1158 DominatorTree *DT; 1166​ DominatorTree *DT;
1159 BlockFrequencyInfo *BFI; 1167​ BlockFrequencyInfo *BFI;
1160 TargetLibraryInfo *TLI; 1168​ TargetLibraryInfo *TLI;
1169​ AliasAnalysis *AA;
1161 bool DisableUnrolling; 1170​ bool DisableUnrolling;
1162 bool AlwaysVectorize; 1171​ bool AlwaysVectorize;
1163 1172​
1164 BlockFrequency ColdEntryFreq; 1173​ BlockFrequency ColdEntryFreq;
1165 1174​
1166 bool runOnFunction(Function &F) override { 1175​ bool runOnFunction(Function &F) override {
1167 SE = &getAnalysis<ScalarEvolution>(); 1176​ SE = &getAnalysis<ScalarEvolution>();
1168 DataLayoutPass *DLP = getAnalysisIfAvailable<DataLayoutPass>(); 1177​ DataLayoutPass *DLP = getAnalysisIfAvailable<DataLayoutPass>();
1169 DL = DLP ? &DLP->getDataLayout() : nullptr; 1178​ DL = DLP ? &DLP->getDataLayout() : nullptr;
1170 LI = &getAnalysis<LoopInfo>(); 1179​ LI = &getAnalysis<LoopInfo>();
1171 TTI = &getAnalysis<TargetTransformInfo>(); 1180​ TTI = &getAnalysis<TargetTransformInfo>();
1172 DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree(); 1181​ DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
1173 BFI = &getAnalysis<BlockFrequencyInfo>(); 1182​ BFI = &getAnalysis<BlockFrequencyInfo>();
1174 TLI = getAnalysisIfAvailable<TargetLibraryInfo>(); 1183​ TLI = getAnalysisIfAvailable<TargetLibraryInfo>();
1184​ AA = &getAnalysis<AliasAnalysis>();
1175 1185​
1176 // Compute some weights outside of the loop over the loops. Compute this 1186​ // Compute some weights outside of the loop over the loops. Compute this
1177 // using a BranchProbability to re-use its scaling math. 1187​ // using a BranchProbability to re-use its scaling math.
1178 const BranchProbability ColdProb(1, 5); // 20% 1188​ const BranchProbability ColdProb(1, 5); // 20%
1179 ColdEntryFreq = BlockFrequency(BFI->getEntryFreq()) * ColdProb; 1189​ ColdEntryFreq = BlockFrequency(BFI->getEntryFreq()) * ColdProb;
1180 1190​
1181 // If the target claims to have no vector registers don't attempt 1191​ // If the target claims to have no vector registers don't attempt
1182 // vectorization. 1192​ // vectorization.
▲ Show 20 Lines • Show All 95 Lines • ▼ Show 20 Line(s)1286 else {
1278 emitOptimizationRemarkAnalysis( 1288​ emitOptimizationRemarkAnalysis(
1279 F->getContext(), DEBUG_TYPE, *F, L->getStartLoc(), 1289​ F->getContext(), DEBUG_TYPE, *F, L->getStartLoc(),
1280 "vectorization is not beneficial and is not explicitly forced"); 1290​ "vectorization is not beneficial and is not explicitly forced");
1281 return false; 1291​ return false;
1282 } 1292​ }
1283 } 1293​ }
1284 1294​
1285 // Check if it is legal to vectorize the loop. 1295​ // Check if it is legal to vectorize the loop.
1286 LoopVectorizationLegality LVL(L, SE, DL, DT, TLI, F); 1296​ LoopVectorizationLegality LVL(L, SE, DL, DT, TLI, AA, F);
1287 if (!LVL.canVectorize()) { 1297​ if (!LVL.canVectorize()) {
1288 DEBUG(dbgs() << "LV: Not vectorizing: Cannot prove legality.\n"); 1298​ DEBUG(dbgs() << "LV: Not vectorizing: Cannot prove legality.\n");
1289 emitMissedWarning(F, L, Hints); 1299​ emitMissedWarning(F, L, Hints);
1290 return false; 1300​ return false;
1291 } 1301​ }
1292 1302​
1293 // Use the cost model. 1303​ // Use the cost model.
1294 LoopVectorizationCostModel CM(L, SE, LI, &LVL, *TTI, DL, TLI); 1304​ LoopVectorizationCostModel CM(L, SE, LI, &LVL, *TTI, DL, TLI);
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1382 void getAnalysisUsage(AnalysisUsage &AU) const override { 1392​ void getAnalysisUsage(AnalysisUsage &AU) const override {
1383 AU.addRequiredID(LoopSimplifyID); 1393​ AU.addRequiredID(LoopSimplifyID);
1384 AU.addRequiredID(LCSSAID); 1394​ AU.addRequiredID(LCSSAID);
1385 AU.addRequired<BlockFrequencyInfo>(); 1395​ AU.addRequired<BlockFrequencyInfo>();
1386 AU.addRequired<DominatorTreeWrapperPass>(); 1396​ AU.addRequired<DominatorTreeWrapperPass>();
1387 AU.addRequired<LoopInfo>(); 1397​ AU.addRequired<LoopInfo>();
1388 AU.addRequired<ScalarEvolution>(); 1398​ AU.addRequired<ScalarEvolution>();
1389 AU.addRequired<TargetTransformInfo>(); 1399​ AU.addRequired<TargetTransformInfo>();
1400​ AU.addRequired<AliasAnalysis>();
1390 AU.addPreserved<LoopInfo>(); 1401​ AU.addPreserved<LoopInfo>();
1391 AU.addPreserved<DominatorTreeWrapperPass>(); 1402​ AU.addPreserved<DominatorTreeWrapperPass>();
1403​ AU.addPreserved<AliasAnalysis>();
1392 } 1404​ }
1393 1405​
1394}; 1406​};
1395 1407​
1396} // end anonymous namespace 1408​} // end anonymous namespace
1397 1409​
1398//===----------------------------------------------------------------------===// 1410​//===----------------------------------------------------------------------===//
1399// Implementation of LoopVectorizationLegality, InnerLoopVectorizer and 1411​// Implementation of LoopVectorizationLegality, InnerLoopVectorizer and
Show All 39 Lines1426static const SCEV *replaceSymbolicStrideSCEV(ScalarEvolution *SE,
1439 } 1451​ }
1440 1452​
1441 // Otherwise, just return the SCEV of the original pointer. 1453​ // Otherwise, just return the SCEV of the original pointer.
1442 return SE->getSCEV(Ptr); 1454​ return SE->getSCEV(Ptr);
1443} 1455​}
1444 1456​
1445void LoopVectorizationLegality::RuntimePointerCheck::insert( 1457​void LoopVectorizationLegality::RuntimePointerCheck::insert(
1446 ScalarEvolution *SE, Loop *Lp, Value *Ptr, bool WritePtr, unsigned DepSetId, 1458​ ScalarEvolution *SE, Loop *Lp, Value *Ptr, bool WritePtr, unsigned DepSetId,
1447 ValueToValueMap &Strides) { 1459​ unsigned ASId, ValueToValueMap &Strides) {
1448 // Get the stride replaced scev. 1460​ // Get the stride replaced scev.
1449 const SCEV *Sc = replaceSymbolicStrideSCEV(SE, Strides, Ptr); 1461​ const SCEV *Sc = replaceSymbolicStrideSCEV(SE, Strides, Ptr);
1450 const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Sc); 1462​ const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Sc);
1451 assert(AR && "Invalid addrec expression"); 1463​ assert(AR && "Invalid addrec expression");
1452 const SCEV *Ex = SE->getBackedgeTakenCount(Lp); 1464​ const SCEV *Ex = SE->getBackedgeTakenCount(Lp);
1453 const SCEV *ScEnd = AR->evaluateAtIteration(Ex, *SE); 1465​ const SCEV *ScEnd = AR->evaluateAtIteration(Ex, *SE);
1454 Pointers.push_back(Ptr); 1466​ Pointers.push_back(Ptr);
1455 Starts.push_back(AR->getStart()); 1467​ Starts.push_back(AR->getStart());
1456 Ends.push_back(ScEnd); 1468​ Ends.push_back(ScEnd);
1457 IsWritePtr.push_back(WritePtr); 1469​ IsWritePtr.push_back(WritePtr);
1458 DependencySetId.push_back(DepSetId); 1470​ DependencySetId.push_back(DepSetId);
1471​ AliasSetId.push_back(ASId);
1459} 1472​}
1460 1473​
1461Value *InnerLoopVectorizer::getBroadcastInstrs(Value *V) { 1474​Value *InnerLoopVectorizer::getBroadcastInstrs(Value *V) {
1462 // We need to place the broadcast of invariant variables outside the loop. 1475​ // We need to place the broadcast of invariant variables outside the loop.
1463 Instruction *Instr = dyn_cast<Instruction>(V); 1476​ Instruction *Instr = dyn_cast<Instruction>(V);
1464 bool NewInstr = 1477​ bool NewInstr =
1465 (Instr && std::find(LoopVectorBody.begin(), LoopVectorBody.end(), 1478​ (Instr && std::find(LoopVectorBody.begin(), LoopVectorBody.end(),
1466 Instr->getParent()) != LoopVectorBody.end()); 1479​ Instr->getParent()) != LoopVectorBody.end());
▲ Show 20 Lines • Show All 529 Lines • ▼ Show 20 Line(s)2008 for (unsigned i = 0; i < NumPointers; ++i) {
1996 for (unsigned j = i+1; j < NumPointers; ++j) { 2009​ for (unsigned j = i+1; j < NumPointers; ++j) {
1997 // No need to check if two readonly pointers intersect. 2010​ // No need to check if two readonly pointers intersect.
1998 if (!PtrRtCheck->IsWritePtr[i] && !PtrRtCheck->IsWritePtr[j]) 2011​ if (!PtrRtCheck->IsWritePtr[i] && !PtrRtCheck->IsWritePtr[j])
1999 continue; 2012​ continue;
2000 2013​
2001 // Only need to check pointers between two different dependency sets. 2014​ // Only need to check pointers between two different dependency sets.
2002 if (PtrRtCheck->DependencySetId[i] == PtrRtCheck->DependencySetId[j]) 2015​ if (PtrRtCheck->DependencySetId[i] == PtrRtCheck->DependencySetId[j])
2003 continue; 2016​ continue;
2017​ // Only need to check pointers in the same alias set.
2018​ if (PtrRtCheck->AliasSetId[i] != PtrRtCheck->AliasSetId[j])
2019​ continue;
2004 2020​
2005 unsigned AS0 = Starts[i]->getType()->getPointerAddressSpace(); 2021​ unsigned AS0 = Starts[i]->getType()->getPointerAddressSpace();
2006 unsigned AS1 = Starts[j]->getType()->getPointerAddressSpace(); 2022​ unsigned AS1 = Starts[j]->getType()->getPointerAddressSpace();
2007 2023​
2008 assert((AS0 == Ends[j]->getType()->getPointerAddressSpace()) && 2024​ assert((AS0 == Ends[j]->getType()->getPointerAddressSpace()) &&
2009 (AS1 == Ends[i]->getType()->getPointerAddressSpace()) && 2025​ (AS1 == Ends[i]->getType()->getPointerAddressSpace()) &&
2010 "Trying to bounds check pointers with different address spaces"); 2026​ "Trying to bounds check pointers with different address spaces");
2011 2027​
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3908public: 3924​public:
3909 /// \brief Read or write access location. 3925​ /// \brief Read or write access location.
3910 typedef PointerIntPair<Value *, 1, bool> MemAccessInfo; 3926​ typedef PointerIntPair<Value *, 1, bool> MemAccessInfo;
3911 typedef SmallPtrSet<MemAccessInfo, 8> MemAccessInfoSet; 3927​ typedef SmallPtrSet<MemAccessInfo, 8> MemAccessInfoSet;
3912 3928​
3913 /// \brief Set of potential dependent memory accesses. 3929​ /// \brief Set of potential dependent memory accesses.
3914 typedef EquivalenceClasses<MemAccessInfo> DepCandidates; 3930​ typedef EquivalenceClasses<MemAccessInfo> DepCandidates;
3915 3931​
3916 AccessAnalysis(const DataLayout *Dl, DepCandidates &DA) : 3932​ AccessAnalysis(const DataLayout *Dl, AliasAnalysis *AA, DepCandidates &DA) :
3917 DL(Dl), DepCands(DA), AreAllWritesIdentified(true), 3933​ DL(Dl), AA(AA), AST(*AA), DepCands(DA), IsRTCheckNeeded(false) {}
3918 AreAllReadsIdentified(true), IsRTCheckNeeded(false) {} ​
3919 3934​
3920 /// \brief Register a load and whether it is only read from. 3935​ /// \brief Register a load and whether it is only read from.
3921 void addLoad(Value *Ptr, bool IsReadOnly) { 3936​ void addLoad(AliasAnalysis::Location &Loc, bool IsReadOnly) {
3937​ Value *Ptr = const_cast<Value*>(Loc.Ptr);
3938​ AST.add(Ptr, AliasAnalysis::UnknownSize, Loc.TBAATag);
3922 Accesses.insert(MemAccessInfo(Ptr, false)); 3939​ Accesses.insert(MemAccessInfo(Ptr, false));
3923 if (IsReadOnly) 3940​ if (IsReadOnly)
3924 ReadOnlyPtr.insert(Ptr); 3941​ ReadOnlyPtr.insert(Ptr);
3925 } 3942​ }
3926 3943​
3927 /// \brief Register a store. 3944​ /// \brief Register a store.
3928 void addStore(Value *Ptr) { 3945​ void addStore(AliasAnalysis::Location &Loc) {
3946​ Value *Ptr = const_cast<Value*>(Loc.Ptr);
3947​ AST.add(Ptr, AliasAnalysis::UnknownSize, Loc.TBAATag);
3929 Accesses.insert(MemAccessInfo(Ptr, true)); 3948​ Accesses.insert(MemAccessInfo(Ptr, true));
3930 } 3949​ }
3931 3950​
3932 /// \brief Check whether we can check the pointers at runtime for 3951​ /// \brief Check whether we can check the pointers at runtime for
3933 /// non-intersection. 3952​ /// non-intersection.
3934 bool canCheckPtrAtRT(LoopVectorizationLegality::RuntimePointerCheck &RtCheck, 3953​ bool canCheckPtrAtRT(LoopVectorizationLegality::RuntimePointerCheck &RtCheck,
3935 unsigned &NumComparisons, ScalarEvolution *SE, 3954​ unsigned &NumComparisons, ScalarEvolution *SE,
3936 Loop *TheLoop, ValueToValueMap &Strides, 3955​ Loop *TheLoop, ValueToValueMap &Strides,
3937 bool ShouldCheckStride = false); 3956​ bool ShouldCheckStride = false);
3938 3957​
3939 /// \brief Goes over all memory accesses, checks whether a RT check is needed 3958​ /// \brief Goes over all memory accesses, checks whether a RT check is needed
3940 /// and builds sets of dependent accesses. 3959​ /// and builds sets of dependent accesses.
3941 void buildDependenceSets() { 3960​ void buildDependenceSets() {
3942 // Process read-write pointers first. 3961​ processMemAccesses();
3943 processMemAccesses(false); ​
3944 // Next, process read pointers. ​
3945 processMemAccesses(true); ​
3946 } 3962​ }
3947 3963​
3948 bool isRTCheckNeeded() { return IsRTCheckNeeded; } 3964​ bool isRTCheckNeeded() { return IsRTCheckNeeded; }
3949 3965​
3950 bool isDependencyCheckNeeded() { return !CheckDeps.empty(); } 3966​ bool isDependencyCheckNeeded() { return !CheckDeps.empty(); }
3951 void resetDepChecks() { CheckDeps.clear(); } 3967​ void resetDepChecks() { CheckDeps.clear(); }
3952 3968​
3953 MemAccessInfoSet &getDependenciesToCheck() { return CheckDeps; } 3969​ MemAccessInfoSet &getDependenciesToCheck() { return CheckDeps; }
3954 3970​
3955private: 3971​private:
3956 typedef SetVector<MemAccessInfo> PtrAccessSet; 3972​ typedef SetVector<MemAccessInfo> PtrAccessSet;
3957 typedef DenseMap<Value*, MemAccessInfo> UnderlyingObjToAccessMap; ​
3958 3973​
3959 /// \brief Go over all memory access or only the deferred ones if 3974​ /// \brief Go over all memory access and check whether runtime pointer checks
3960 /// \p UseDeferred is true and check whether runtime pointer checks are needed 3975​ /// are needed /// and build sets of dependency check candidates.
3961 /// and build sets of dependency check candidates. 3976​ void processMemAccesses();
3962 void processMemAccesses(bool UseDeferred); ​
3963 3977​
3964 /// Set of all accesses. 3978​ /// Set of all accesses.
3965 PtrAccessSet Accesses; 3979​ PtrAccessSet Accesses;
3966 3980​
3967 /// Set of access to check after all writes have been processed. ​
3968 PtrAccessSet DeferredAccesses; ​
3969 ​
3970 /// Map of pointers to last access encountered. ​
3971 UnderlyingObjToAccessMap ObjToLastAccess; ​
3972 ​
3973 /// Set of accesses that need a further dependence check. 3981​ /// Set of accesses that need a further dependence check.
3974 MemAccessInfoSet CheckDeps; 3982​ MemAccessInfoSet CheckDeps;
3975 3983​
3976 /// Set of pointers that are read only. 3984​ /// Set of pointers that are read only.
3977 SmallPtrSet<Value*, 16> ReadOnlyPtr; 3985​ SmallPtrSet<Value*, 16> ReadOnlyPtr;
3978 3986​
3979 /// Set of underlying objects already written to. ​
3980 SmallPtrSet<Value*, 16> WriteObjects; ​
3981 ​
3982 const DataLayout *DL; 3987​ const DataLayout *DL;
3988​ AliasAnalysis *AA;
3989​
3990​ /// An alias set tracker to partition the access set by underlying object and
3991​ //intrinsic property (such as TBAA metadata).
3992​ AliasSetTracker AST;
3983 3993​
3984 /// Sets of potentially dependent accesses - members of one set share an 3994​ /// Sets of potentially dependent accesses - members of one set share an
3985 /// underlying pointer. The set "CheckDeps" identfies which sets really need a 3995​ /// underlying pointer. The set "CheckDeps" identfies which sets really need a
3986 /// dependence check. 3996​ /// dependence check.
3987 DepCandidates &DepCands; 3997​ DepCandidates &DepCands;
3988 3998​
3989 bool AreAllWritesIdentified; ​
3990 bool AreAllReadsIdentified; ​
3991 bool IsRTCheckNeeded; 3999​ bool IsRTCheckNeeded;
3992}; 4000​};
3993 4001​
3994} // end anonymous namespace 4002​} // end anonymous namespace
3995 4003​
3996/// \brief Check whether a pointer can participate in a runtime bounds check. 4004​/// \brief Check whether a pointer can participate in a runtime bounds check.
3997static bool hasComputableBounds(ScalarEvolution *SE, ValueToValueMap &Strides, 4005​static bool hasComputableBounds(ScalarEvolution *SE, ValueToValueMap &Strides,
3998 Value *Ptr) { 4006​ Value *Ptr) {
Show All 11 Lines4017static int isStridedPtr(ScalarEvolution *SE, const DataLayout *DL, Value *Ptr,
4010 const Loop *Lp, ValueToValueMap &StridesMap); 4018​ const Loop *Lp, ValueToValueMap &StridesMap);
4011 4019​
4012bool AccessAnalysis::canCheckPtrAtRT( 4020​bool AccessAnalysis::canCheckPtrAtRT(
4013 LoopVectorizationLegality::RuntimePointerCheck &RtCheck, 4021​ LoopVectorizationLegality::RuntimePointerCheck &RtCheck,
4014 unsigned &NumComparisons, ScalarEvolution *SE, Loop *TheLoop, 4022​ unsigned &NumComparisons, ScalarEvolution *SE, Loop *TheLoop,
4015 ValueToValueMap &StridesMap, bool ShouldCheckStride) { 4023​ ValueToValueMap &StridesMap, bool ShouldCheckStride) {
4016 // Find pointers with computable bounds. We are going to use this information 4024​ // Find pointers with computable bounds. We are going to use this information
4017 // to place a runtime bound check. 4025​ // to place a runtime bound check.
4018 unsigned NumReadPtrChecks = 0; ​
4019 unsigned NumWritePtrChecks = 0; ​
4020 bool CanDoRT = true; 4026​ bool CanDoRT = true;
4021 4027​
4022 bool IsDepCheckNeeded = isDependencyCheckNeeded(); 4028​ bool IsDepCheckNeeded = isDependencyCheckNeeded();
4029​ NumComparisons = 0;
4030​
4031​ // We assign a consecutive id to access from different alias sets.
4032​ // Accesses between different groups doesn't need to be checked.
4033​ unsigned ASId = 1;
4034​ for (auto &AS : AST) {
4035​ unsigned NumReadPtrChecks = 0;
4036​ unsigned NumWritePtrChecks = 0;
4037​
4023 // We assign consecutive id to access from different dependence sets. 4038​ // We assign consecutive id to access from different dependence sets.
4024 // Accesses within the same set don't need a runtime check. 4039​ // Accesses within the same set don't need a runtime check.
4025 unsigned RunningDepId = 1; 4040​ unsigned RunningDepId = 1;
4026 DenseMap<Value *, unsigned> DepSetId; 4041​ DenseMap<Value *, unsigned> DepSetId;
4027 4042​
4028 for (PtrAccessSet::iterator AI = Accesses.begin(), AE = Accesses.end(); 4043​ for (auto A : AS) {
4029 AI != AE; ++AI) { 4044​ Value *Ptr = A.getValue();
4030 const MemAccessInfo &Access = *AI; 4045​ bool IsWrite = Accesses.count(MemAccessInfo(Ptr, true));
4031 Value *Ptr = Access.getPointer(); 4046​ MemAccessInfo Access(Ptr, IsWrite);
4032 bool IsWrite = Access.getInt(); ​
4033 ​
4034 // Just add write checks if we have both. ​
4035 if (!IsWrite && Accesses.count(MemAccessInfo(Ptr, true))) ​
4036 continue; ​
4037 4047​
4038 if (IsWrite) 4048​ if (IsWrite)
4039 ++NumWritePtrChecks; 4049​ ++NumWritePtrChecks;
4040 else 4050​ else
4041 ++NumReadPtrChecks; 4051​ ++NumReadPtrChecks;
4042 4052​
4043 if (hasComputableBounds(SE, StridesMap, Ptr) && 4053​ if (hasComputableBounds(SE, StridesMap, Ptr) &&
4044 // When we run after a failing dependency check we have to make sure we 4054​ // When we run after a failing dependency check we have to make sure we
4045 // don't have wrapping pointers. 4055​ // don't have wrapping pointers.
4046 (!ShouldCheckStride || 4056​ (!ShouldCheckStride ||
4047 isStridedPtr(SE, DL, Ptr, TheLoop, StridesMap) == 1)) { 4057​ isStridedPtr(SE, DL, Ptr, TheLoop, StridesMap) == 1)) {
4048 // The id of the dependence set. 4058​ // The id of the dependence set.
4049 unsigned DepId; 4059​ unsigned DepId;
4050 4060​
4051 if (IsDepCheckNeeded) { 4061​ if (IsDepCheckNeeded) {
4052 Value *Leader = DepCands.getLeaderValue(Access).getPointer(); 4062​ Value *Leader = DepCands.getLeaderValue(Access).getPointer();
4053 unsigned &LeaderId = DepSetId[Leader]; 4063​ unsigned &LeaderId = DepSetId[Leader];
4054 if (!LeaderId) 4064​ if (!LeaderId)
4055 LeaderId = RunningDepId++; 4065​ LeaderId = RunningDepId++;
4056 DepId = LeaderId; 4066​ DepId = LeaderId;
4057 } else 4067​ } else
4058 // Each access has its own dependence set. 4068​ // Each access has its own dependence set.
4059 DepId = RunningDepId++; 4069​ DepId = RunningDepId++;
4060 4070​
4061 RtCheck.insert(SE, TheLoop, Ptr, IsWrite, DepId, StridesMap); 4071​ RtCheck.insert(SE, TheLoop, Ptr, IsWrite, DepId, ASId, StridesMap);
4062 4072​
4063 DEBUG(dbgs() << "LV: Found a runtime check ptr:" << *Ptr << '\n'); 4073​ DEBUG(dbgs() << "LV: Found a runtime check ptr:" << *Ptr << '\n');
4064 } else { 4074​ } else {
4065 CanDoRT = false; 4075​ CanDoRT = false;
4066 } 4076​ }
4067 } 4077​ }
4068 4078​
4069 if (IsDepCheckNeeded && CanDoRT && RunningDepId == 2) 4079​ if (IsDepCheckNeeded && CanDoRT && RunningDepId == 2)
4070 NumComparisons = 0; // Only one dependence set. 4080​ NumComparisons += 0; // Only one dependence set.
4071 else { 4081​ else {
4072 NumComparisons = (NumWritePtrChecks * (NumReadPtrChecks + 4082​ NumComparisons += (NumWritePtrChecks * (NumReadPtrChecks +
4073 NumWritePtrChecks - 1)); 4083​ NumWritePtrChecks - 1));
4074 } 4084​ }
4075 4085​
4086​ ++ASId;
4087​ }
4088​
4076 // If the pointers that we would use for the bounds comparison have different 4089​ // If the pointers that we would use for the bounds comparison have different
4077 // address spaces, assume the values aren't directly comparable, so we can't 4090​ // address spaces, assume the values aren't directly comparable, so we can't
4078 // use them for the runtime check. We also have to assume they could 4091​ // use them for the runtime check. We also have to assume they could
4079 // overlap. In the future there should be metadata for whether address spaces 4092​ // overlap. In the future there should be metadata for whether address spaces
4080 // are disjoint. 4093​ // are disjoint.
4081 unsigned NumPointers = RtCheck.Pointers.size(); 4094​ unsigned NumPointers = RtCheck.Pointers.size();
4082 for (unsigned i = 0; i < NumPointers; ++i) { 4095​ for (unsigned i = 0; i < NumPointers; ++i) {
4083 for (unsigned j = i + 1; j < NumPointers; ++j) { 4096​ for (unsigned j = i + 1; j < NumPointers; ++j) {
4084 // Only need to check pointers between two different dependency sets. 4097​ // Only need to check pointers between two different dependency sets.
4085 if (RtCheck.DependencySetId[i] == RtCheck.DependencySetId[j]) 4098​ if (RtCheck.DependencySetId[i] == RtCheck.DependencySetId[j])
4086 continue; 4099​ continue;
4100​ // Only need to check pointers in the same alias set.
4101​ if (RtCheck.AliasSetId[i] != RtCheck.AliasSetId[j])
4102​ continue;
4087 4103​
4088 Value *PtrI = RtCheck.Pointers[i]; 4104​ Value *PtrI = RtCheck.Pointers[i];
4089 Value *PtrJ = RtCheck.Pointers[j]; 4105​ Value *PtrJ = RtCheck.Pointers[j];
4090 4106​
4091 unsigned ASi = PtrI->getType()->getPointerAddressSpace(); 4107​ unsigned ASi = PtrI->getType()->getPointerAddressSpace();
4092 unsigned ASj = PtrJ->getType()->getPointerAddressSpace(); 4108​ unsigned ASj = PtrJ->getType()->getPointerAddressSpace();
4093 if (ASi != ASj) { 4109​ if (ASi != ASj) {
4094 DEBUG(dbgs() << "LV: Runtime check would require comparison between" 4110​ DEBUG(dbgs() << "LV: Runtime check would require comparison between"
4095 " different address spaces\n"); 4111​ " different address spaces\n");
4096 return false; 4112​ return false;
4097 } 4113​ }
4098 } 4114​ }
4099 } 4115​ }
4100 4116​
4101 return CanDoRT; 4117​ return CanDoRT;
4102} 4118​}
4103 4119​
4104static bool isFunctionScopeIdentifiedObject(Value *Ptr) { 4120​void AccessAnalysis::processMemAccesses() {
4105 return isNoAliasArgument(Ptr) || isNoAliasCall(Ptr) || isa<AllocaInst>(Ptr); ​
4106} ​
4107 ​
4108void AccessAnalysis::processMemAccesses(bool UseDeferred) { ​
4109 // We process the set twice: first we process read-write pointers, last we 4121​ // We process the set twice: first we process read-write pointers, last we
4110 // process read-only pointers. This allows us to skip dependence tests for 4122​ // process read-only pointers. This allows us to skip dependence tests for
4111 // read-only pointers. 4123​ // read-only pointers.
4112 4124​
4125​ DEBUG(dbgs() << "LV: Processing memory accesses...\n");
4126​ DEBUG(dbgs() << " AST: "; AST.dump());
4127​ DEBUG(dbgs() << "LV: Accesses:\n");
4128​ DEBUG({
4129​ for (auto A : Accesses)
4130​ dbgs() << "\t" << *A.getPointer() << " (" <<
4131​ (A.getInt() ? "write" : (ReadOnlyPtr.count(A.getPointer()) ?
4132​ "read-only" : "read")) << ")\n";
4133​ });
4134​
4135​ // The AliasSetTracker has nicely partitioned our pointers by metadata
4136​ // compatibility and potential for underlying-object overlap. As a result, we
4137​ // only need to check for potential pointer dependencies within each alias
4138​ // set.
4139​ for (auto &AS : AST) {
4140​ // Note that both the alias-set tracker and the alias sets themselves used
4141​ // linked lists internally and so the iteration order here is deterministic
4142​ // (matching the original instruction order within each set).
4143​
4144​ bool SetHasWrite = false;
4145​
4146​ // Map of pointers to last access encountered.
4147​ typedef DenseMap<Value*, MemAccessInfo> UnderlyingObjToAccessMap;
4148​ UnderlyingObjToAccessMap ObjToLastAccess;
4149​
4150​ // Set of access to check after all writes have been processed.
4151​ PtrAccessSet DeferredAccesses;
4152​
4153​ // Iterate over each alias set twice, once to process read/write pointers,
4154​ // and then to process read-only pointers.
4155​ for (int SetIteration = 0; SetIteration < 2; ++SetIteration) {
4156​ bool UseDeferred = SetIteration > 0;
4113 PtrAccessSet &S = UseDeferred ? DeferredAccesses : Accesses; 4157​ PtrAccessSet &S = UseDeferred ? DeferredAccesses : Accesses;
4114 for (PtrAccessSet::iterator AI = S.begin(), AE = S.end(); AI != AE; ++AI) { ​
4115 const MemAccessInfo &Access = *AI; ​
4116 Value *Ptr = Access.getPointer(); ​
4117 bool IsWrite = Access.getInt(); ​
4118 4158​
4159​ for (auto A : AS) {
4160​ Value *Ptr = A.getValue();
4161​ bool IsWrite = S.count(MemAccessInfo(Ptr, true));
4162​
4163​ // If we're using the deferred access set, then it contains only reads.
4164​ bool IsReadOnlyPtr = ReadOnlyPtr.count(Ptr) && !IsWrite;
4165​ if (UseDeferred && !IsReadOnlyPtr)
4166​ continue;
4167​ // Otherwise, the pointer must be in the PtrAccessSet, either as a read
4168​ // or a write.
4169​ assert(((IsReadOnlyPtr && UseDeferred) || IsWrite ||
4170​ S.count(MemAccessInfo(Ptr, false))) &&
4171​ "Alias-set pointer not in the access set?");
4172​
4173​ MemAccessInfo Access(Ptr, IsWrite);
4119 DepCands.insert(Access); 4174​ DepCands.insert(Access);
4120 4175​
4121 // Memorize read-only pointers for later processing and skip them in the 4176​ // Memorize read-only pointers for later processing and skip them in the
4122 // first round (they need to be checked after we have seen all write 4177​ // first round (they need to be checked after we have seen all write
4123 // pointers). Note: we also mark pointer that are not consecutive as 4178​ // pointers). Note: we also mark pointer that are not consecutive as
4124 // "read-only" pointers (so that we check "a[b[i]] +="). Hence, we need the 4179​ // "read-only" pointers (so that we check "a[b[i]] +="). Hence, we need
4125 // second check for "!IsWrite". 4180​ // the second check for "!IsWrite".
4126 bool IsReadOnlyPtr = ReadOnlyPtr.count(Ptr) && !IsWrite; ​
4127 if (!UseDeferred && IsReadOnlyPtr) { 4181​ if (!UseDeferred && IsReadOnlyPtr) {
4128 DeferredAccesses.insert(Access); 4182​ DeferredAccesses.insert(Access);
4129 continue; 4183​ continue;
4130 } 4184​ }
4131 4185​
4132 bool NeedDepCheck = false; ​
4133 // Check whether there is the possibility of dependency because of ​
4134 // underlying objects being the same. ​
4135 typedef SmallVector<Value*, 16> ValueVector; ​
4136 ValueVector TempObjects; ​
4137 GetUnderlyingObjects(Ptr, TempObjects, DL); ​
4138 for (ValueVector::iterator UI = TempObjects.begin(), UE = TempObjects.end(); ​
4139 UI != UE; ++UI) { ​
4140 Value *UnderlyingObj = *UI; ​
4141 ​
4142 // If this is a write then it needs to be an identified object. If this a ​
4143 // read and all writes (so far) are identified function scope objects we ​
4144 // don't need an identified underlying object but only an Argument (the ​
4145 // next write is going to invalidate this assumption if it is ​
4146 // unidentified). ​
4147 // This is a micro-optimization for the case where all writes are ​
4148 // identified and we have one argument pointer. ​
4149 // Otherwise, we do need a runtime check. ​
4150 if ((IsWrite && !isFunctionScopeIdentifiedObject(UnderlyingObj)) || ​
4151 (!IsWrite && (!AreAllWritesIdentified || ​
4152 !isa<Argument>(UnderlyingObj)) && ​
4153 !isIdentifiedObject(UnderlyingObj))) { ​
4154 DEBUG(dbgs() << "LV: Found an unidentified " << ​
4155 (IsWrite ? "write" : "read" ) << " ptr: " << *UnderlyingObj << ​
4156 "\n"); ​
4157 IsRTCheckNeeded = (IsRTCheckNeeded || ​
4158 !isIdentifiedObject(UnderlyingObj) || ​
4159 !AreAllReadsIdentified); ​
4160 ​
4161 if (IsWrite) ​
4162 AreAllWritesIdentified = false; ​
4163 if (!IsWrite) ​
4164 AreAllReadsIdentified = false; ​
4165 } ​
4166 ​
4167 // If this is a write - check other reads and writes for conflicts. If 4186​ // If this is a write - check other reads and writes for conflicts. If
4168 // this is a read only check other writes for conflicts (but only if there 4187​ // this is a read only check other writes for conflicts (but only if
4169 // is no other write to the ptr - this is an optimization to catch "a[i] = 4188​ // there is no other write to the ptr - this is an optimization to
4170 // a[i] + " without having to do a dependence check). 4189​ // catch "a[i] = a[i] + " without having to do a dependence check).
4171 if ((IsWrite || IsReadOnlyPtr) && WriteObjects.count(UnderlyingObj)) 4190​ if ((IsWrite || IsReadOnlyPtr) && SetHasWrite) {
4172 NeedDepCheck = true; 4191​ CheckDeps.insert(Access);
4192​ IsRTCheckNeeded = true;
4193​ }
4173 4194​
4174 if (IsWrite) 4195​ if (IsWrite)
4175 WriteObjects.insert(UnderlyingObj); 4196​ SetHasWrite = true;
4176 4197​
4177 // Create sets of pointers connected by shared underlying objects. 4198​ // Create sets of pointers connected by a shared alias set and
4199​ // underlying object.
4200​ typedef SmallVector<Value*, 16> ValueVector;
4201​ ValueVector TempObjects;
4202​ GetUnderlyingObjects(Ptr, TempObjects, DL);
4203​ for (Value *UnderlyingObj : TempObjects) {
4178 UnderlyingObjToAccessMap::iterator Prev = 4204​ UnderlyingObjToAccessMap::iterator Prev =
4179 ObjToLastAccess.find(UnderlyingObj); 4205​ ObjToLastAccess.find(UnderlyingObj);
4180 if (Prev != ObjToLastAccess.end()) 4206​ if (Prev != ObjToLastAccess.end())
4181 DepCands.unionSets(Access, Prev->second); 4207​ DepCands.unionSets(Access, Prev->second);
4182 4208​
4183 ObjToLastAccess[UnderlyingObj] = Access; 4209​ ObjToLastAccess[UnderlyingObj] = Access;
4184 } 4210​ }
4185 4211​ }
4186 if (NeedDepCheck) 4212​ }
4187 CheckDeps.insert(Access); ​
4188 } 4213​ }
4189} 4214​}
4190 4215​
4191namespace { 4216​namespace {
4192/// \brief Checks memory dependences among accesses to the same underlying 4217​/// \brief Checks memory dependences among accesses to the same underlying
4193/// object to determine whether there vectorization is legal or not (and at 4218​/// object to determine whether there vectorization is legal or not (and at
4194/// which vectorization factor). 4219​/// which vectorization factor).
4195/// 4220​///
▲ Show 20 Lines • Show All 243 Lines • ▼ Show 20 Line(s)4458bool MemoryDepChecker::isDependent(const MemAccessInfo &A, unsigned AIdx,
4439 Value *BPtr = B.getPointer(); 4464​ Value *BPtr = B.getPointer();
4440 bool AIsWrite = A.getInt(); 4465​ bool AIsWrite = A.getInt();
4441 bool BIsWrite = B.getInt(); 4466​ bool BIsWrite = B.getInt();
4442 4467​
4443 // Two reads are independent. 4468​ // Two reads are independent.
4444 if (!AIsWrite && !BIsWrite) 4469​ if (!AIsWrite && !BIsWrite)
4445 return false; 4470​ return false;
4446 4471​
4472​ // We cannot check pointers in different address spaces.
4473​ if (APtr->getType()->getPointerAddressSpace() !=
4474​ BPtr->getType()->getPointerAddressSpace())
4475​ return true;
4476​
4447 const SCEV *AScev = replaceSymbolicStrideSCEV(SE, Strides, APtr); 4477​ const SCEV *AScev = replaceSymbolicStrideSCEV(SE, Strides, APtr);
4448 const SCEV *BScev = replaceSymbolicStrideSCEV(SE, Strides, BPtr); 4478​ const SCEV *BScev = replaceSymbolicStrideSCEV(SE, Strides, BPtr);
4449 4479​
4450 int StrideAPtr = isStridedPtr(SE, DL, APtr, InnermostLoop, Strides); 4480​ int StrideAPtr = isStridedPtr(SE, DL, APtr, InnermostLoop, Strides);
4451 int StrideBPtr = isStridedPtr(SE, DL, BPtr, InnermostLoop, Strides); 4481​ int StrideBPtr = isStridedPtr(SE, DL, BPtr, InnermostLoop, Strides);
4452 4482​
4453 const SCEV *Src = AScev; 4483​ const SCEV *Src = AScev;
4454 const SCEV *Sink = BScev; 4484​ const SCEV *Sink = BScev;
▲ Show 20 Lines • Show All 214 Lines • ▼ Show 20 Line(s)4625bool LoopVectorizationLegality::canVectorizeMemory() {
4669 // Check if we see any stores. If there are no stores, then we don't 4699​ // Check if we see any stores. If there are no stores, then we don't
4670 // care if the pointers are *restrict*. 4700​ // care if the pointers are *restrict*.
4671 if (!Stores.size()) { 4701​ if (!Stores.size()) {
4672 DEBUG(dbgs() << "LV: Found a read-only loop!\n"); 4702​ DEBUG(dbgs() << "LV: Found a read-only loop!\n");
4673 return true; 4703​ return true;
4674 } 4704​ }
4675 4705​
4676 AccessAnalysis::DepCandidates DependentAccesses; 4706​ AccessAnalysis::DepCandidates DependentAccesses;
4677 AccessAnalysis Accesses(DL, DependentAccesses); 4707​ AccessAnalysis Accesses(DL, AA, DependentAccesses);
4678 4708​
4679 // Holds the analyzed pointers. We don't want to call GetUnderlyingObjects 4709​ // Holds the analyzed pointers. We don't want to call GetUnderlyingObjects
4680 // multiple times on the same object. If the ptr is accessed twice, once 4710​ // multiple times on the same object. If the ptr is accessed twice, once
4681 // for read and once for write, it will only appear once (on the write 4711​ // for read and once for write, it will only appear once (on the write
4682 // list). This is okay, since we are going to check for conflicts between 4712​ // list). This is okay, since we are going to check for conflicts between
4683 // writes and between reads and writes, but not between reads and reads. 4713​ // writes and between reads and writes, but not between reads and reads.
4684 ValueSet Seen; 4714​ ValueSet Seen;
4685 4715​
Show All 9 Lines4721 if (isUniform(Ptr)) {
4695 DEBUG(dbgs() << "LV: We don't allow storing to uniform addresses\n"); 4725​ DEBUG(dbgs() << "LV: We don't allow storing to uniform addresses\n");
4696 return false; 4726​ return false;
4697 } 4727​ }
4698 4728​
4699 // If we did *not* see this pointer before, insert it to the read-write 4729​ // If we did *not* see this pointer before, insert it to the read-write
4700 // list. At this phase it is only a 'write' list. 4730​ // list. At this phase it is only a 'write' list.
4701 if (Seen.insert(Ptr)) { 4731​ if (Seen.insert(Ptr)) {
4702 ++NumReadWrites; 4732​ ++NumReadWrites;
4703 Accesses.addStore(Ptr); 4733​
4734​ AliasAnalysis::Location Loc = AA->getLocation(ST);
4735​ // The TBAA metadata could have a control dependency on the predication
4736​ // condition, so we cannot rely on it when determining whether or not we
4737​ // need runtime pointer checks.
4738​ if (blockNeedsPredication(ST->getParent()))
4739​ Loc.TBAATag = nullptr;
4740​
4741​ Accesses.addStore(Loc);
4704 } 4742​ }
4705 } 4743​ }
4706 4744​
4707 if (IsAnnotatedParallel) { 4745​ if (IsAnnotatedParallel) {
4708 DEBUG(dbgs() 4746​ DEBUG(dbgs()
4709 << "LV: A loop annotated parallel, ignore memory dependency " 4747​ << "LV: A loop annotated parallel, ignore memory dependency "
4710 << "checks.\n"); 4748​ << "checks.\n");
4711 return true; 4749​ return true;
Show All 10 Lines4752 for (I = Loads.begin(), IE = Loads.end(); I != IE; ++I) {
4722 // If the address of i is unknown (for example A[B[i]]) then we may 4760​ // If the address of i is unknown (for example A[B[i]]) then we may
4723 // read a few words, modify, and write a few words, and some of the 4761​ // read a few words, modify, and write a few words, and some of the
4724 // words may be written to the same address. 4762​ // words may be written to the same address.
4725 bool IsReadOnlyPtr = false; 4763​ bool IsReadOnlyPtr = false;
4726 if (Seen.insert(Ptr) || !isStridedPtr(SE, DL, Ptr, TheLoop, Strides)) { 4764​ if (Seen.insert(Ptr) || !isStridedPtr(SE, DL, Ptr, TheLoop, Strides)) {
4727 ++NumReads; 4765​ ++NumReads;
4728 IsReadOnlyPtr = true; 4766​ IsReadOnlyPtr = true;
4729 } 4767​ }
4730 Accesses.addLoad(Ptr, IsReadOnlyPtr); 4768​
4769​ AliasAnalysis::Location Loc = AA->getLocation(LD);
4770​ // The TBAA metadata could have a control dependency on the predication
4771​ // condition, so we cannot rely on it when determining whether or not we
4772​ // need runtime pointer checks.
4773​ if (blockNeedsPredication(LD->getParent()))
4774​ Loc.TBAATag = nullptr;
4775​
4776​ Accesses.addLoad(Loc, IsReadOnlyPtr);
4731 } 4777​ }
4732 4778​
4733 // If we write (or read-write) to a single destination and there are no 4779​ // If we write (or read-write) to a single destination and there are no
4734 // other reads in this loop then is it safe to vectorize. 4780​ // other reads in this loop then is it safe to vectorize.
4735 if (NumReadWrites == 1 && NumReads == 0) { 4781​ if (NumReadWrites == 1 && NumReads == 0) {
4736 DEBUG(dbgs() << "LV: Found a write-only loop!\n"); 4782​ DEBUG(dbgs() << "LV: Found a write-only loop!\n");
4737 return true; 4783​ return true;
4738 } 4784​ }
▲ Show 20 Lines • Show All 1168 Lines • ▼ Show 20 Line(s)5952 if (Scalar->isVoidTy() || VF == 1)
5907 return Scalar; 5953​ return Scalar;
5908 return VectorType::get(Scalar, VF); 5954​ return VectorType::get(Scalar, VF);
5909} 5955​}
5910 5956​
5911char LoopVectorize::ID = 0; 5957​char LoopVectorize::ID = 0;
5912static const char lv_name[] = "Loop Vectorization"; 5958​static const char lv_name[] = "Loop Vectorization";
5913INITIALIZE_PASS_BEGIN(LoopVectorize, LV_NAME, lv_name, false, false) 5959​INITIALIZE_PASS_BEGIN(LoopVectorize, LV_NAME, lv_name, false, false)
5914INITIALIZE_AG_DEPENDENCY(TargetTransformInfo) 5960​INITIALIZE_AG_DEPENDENCY(TargetTransformInfo)
5961​INITIALIZE_AG_DEPENDENCY(AliasAnalysis)
5915INITIALIZE_PASS_DEPENDENCY(BlockFrequencyInfo) 5962​INITIALIZE_PASS_DEPENDENCY(BlockFrequencyInfo)
5916INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass) 5963​INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
5917INITIALIZE_PASS_DEPENDENCY(ScalarEvolution) 5964​INITIALIZE_PASS_DEPENDENCY(ScalarEvolution)
5918INITIALIZE_PASS_DEPENDENCY(LCSSA) 5965​INITIALIZE_PASS_DEPENDENCY(LCSSA)
5919INITIALIZE_PASS_DEPENDENCY(LoopInfo) 5966​INITIALIZE_PASS_DEPENDENCY(LoopInfo)
5920INITIALIZE_PASS_DEPENDENCY(LoopSimplify) 5967​INITIALIZE_PASS_DEPENDENCY(LoopSimplify)
5921INITIALIZE_PASS_END(LoopVectorize, LV_NAME, lv_name, false, false) 5968​INITIALIZE_PASS_END(LoopVectorize, LV_NAME, lv_name, false, false)
5922 5969​
▲ Show 20 Lines • Show All 153 Lines • Show Last 20 Lines