1 //===- llvm/Analysis/LoopAccessAnalysis.h -----------------------*- C++ -*-===//
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 defines the interface for the loop memory dependence framework that
11 // was originally developed for the Loop Vectorizer.
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_ANALYSIS_LOOPACCESSANALYSIS_H
16 #define LLVM_ANALYSIS_LOOPACCESSANALYSIS_H
18 #include "llvm/ADT/EquivalenceClasses.h"
19 #include "llvm/ADT/Optional.h"
20 #include "llvm/ADT/SetVector.h"
21 #include "llvm/Analysis/AliasAnalysis.h"
22 #include "llvm/Analysis/AliasSetTracker.h"
23 #include "llvm/Analysis/ScalarEvolutionExpressions.h"
24 #include "llvm/IR/ValueHandle.h"
25 #include "llvm/Pass.h"
26 #include "llvm/Support/raw_ostream.h"
32 class ScalarEvolution;
35 class SCEVUnionPredicate;
38 /// Optimization analysis message produced during vectorization. Messages inform
39 /// the user why vectorization did not occur.
40 class LoopAccessReport {
42 const Instruction *Instr;
45 LoopAccessReport(const Twine &Message, const Instruction *I)
46 : Message(Message.str()), Instr(I) {}
49 LoopAccessReport(const Instruction *I = nullptr) : Instr(I) {}
51 template <typename A> LoopAccessReport &operator<<(const A &Value) {
52 raw_string_ostream Out(Message);
57 const Instruction *getInstr() const { return Instr; }
59 std::string &str() { return Message; }
60 const std::string &str() const { return Message; }
61 operator Twine() { return Message; }
63 /// \brief Emit an analysis note for \p PassName with the debug location from
64 /// the instruction in \p Message if available. Otherwise use the location of
66 static void emitAnalysis(const LoopAccessReport &Message,
67 const Function *TheFunction,
69 const char *PassName);
72 /// \brief Collection of parameters shared beetween the Loop Vectorizer and the
73 /// Loop Access Analysis.
74 struct VectorizerParams {
75 /// \brief Maximum SIMD width.
76 static const unsigned MaxVectorWidth;
78 /// \brief VF as overridden by the user.
79 static unsigned VectorizationFactor;
80 /// \brief Interleave factor as overridden by the user.
81 static unsigned VectorizationInterleave;
82 /// \brief True if force-vector-interleave was specified by the user.
83 static bool isInterleaveForced();
85 /// \\brief When performing memory disambiguation checks at runtime do not
86 /// make more than this number of comparisons.
87 static unsigned RuntimeMemoryCheckThreshold;
90 /// \brief Checks memory dependences among accesses to the same underlying
91 /// object to determine whether there vectorization is legal or not (and at
92 /// which vectorization factor).
94 /// Note: This class will compute a conservative dependence for access to
95 /// different underlying pointers. Clients, such as the loop vectorizer, will
96 /// sometimes deal these potential dependencies by emitting runtime checks.
98 /// We use the ScalarEvolution framework to symbolically evalutate access
99 /// functions pairs. Since we currently don't restructure the loop we can rely
100 /// on the program order of memory accesses to determine their safety.
101 /// At the moment we will only deem accesses as safe for:
102 /// * A negative constant distance assuming program order.
104 /// Safe: tmp = a[i + 1]; OR a[i + 1] = x;
105 /// a[i] = tmp; y = a[i];
107 /// The latter case is safe because later checks guarantuee that there can't
108 /// be a cycle through a phi node (that is, we check that "x" and "y" is not
109 /// the same variable: a header phi can only be an induction or a reduction, a
110 /// reduction can't have a memory sink, an induction can't have a memory
111 /// source). This is important and must not be violated (or we have to
112 /// resort to checking for cycles through memory).
114 /// * A positive constant distance assuming program order that is bigger
115 /// than the biggest memory access.
117 /// tmp = a[i] OR b[i] = x
118 /// a[i+2] = tmp y = b[i+2];
120 /// Safe distance: 2 x sizeof(a[0]), and 2 x sizeof(b[0]), respectively.
122 /// * Zero distances and all accesses have the same size.
124 class MemoryDepChecker {
126 typedef PointerIntPair<Value *, 1, bool> MemAccessInfo;
127 typedef SmallPtrSet<MemAccessInfo, 8> MemAccessInfoSet;
128 /// \brief Set of potential dependent memory accesses.
129 typedef EquivalenceClasses<MemAccessInfo> DepCandidates;
131 /// \brief Dependece between memory access instructions.
133 /// \brief The type of the dependence.
137 // We couldn't determine the direction or the distance.
139 // Lexically forward.
141 // FIXME: If we only have loop-independent forward dependences (e.g. a
142 // read and write of A[i]), LAA will locally deem the dependence "safe"
143 // without querying the MemoryDepChecker. Therefore we can miss
144 // enumerating loop-independent forward dependences in
145 // getDependences. Note that as soon as there are different
146 // indices used to access the same array, the MemoryDepChecker *is*
147 // queried and the dependence list is complete.
149 // Forward, but if vectorized, is likely to prevent store-to-load
151 ForwardButPreventsForwarding,
152 // Lexically backward.
154 // Backward, but the distance allows a vectorization factor of
155 // MaxSafeDepDistBytes.
156 BackwardVectorizable,
157 // Same, but may prevent store-to-load forwarding.
158 BackwardVectorizableButPreventsForwarding
161 /// \brief String version of the types.
162 static const char *DepName[];
164 /// \brief Index of the source of the dependence in the InstMap vector.
166 /// \brief Index of the destination of the dependence in the InstMap vector.
167 unsigned Destination;
168 /// \brief The type of the dependence.
171 Dependence(unsigned Source, unsigned Destination, DepType Type)
172 : Source(Source), Destination(Destination), Type(Type) {}
174 /// \brief Return the source instruction of the dependence.
175 Instruction *getSource(const LoopAccessInfo &LAI) const;
176 /// \brief Return the destination instruction of the dependence.
177 Instruction *getDestination(const LoopAccessInfo &LAI) const;
179 /// \brief Dependence types that don't prevent vectorization.
180 static bool isSafeForVectorization(DepType Type);
182 /// \brief Lexically forward dependence.
183 bool isForward() const;
184 /// \brief Lexically backward dependence.
185 bool isBackward() const;
187 /// \brief May be a lexically backward dependence type (includes Unknown).
188 bool isPossiblyBackward() const;
190 /// \brief Print the dependence. \p Instr is used to map the instruction
191 /// indices to instructions.
192 void print(raw_ostream &OS, unsigned Depth,
193 const SmallVectorImpl<Instruction *> &Instrs) const;
196 MemoryDepChecker(ScalarEvolution *Se, const Loop *L,
197 SCEVUnionPredicate &Preds)
198 : SE(Se), InnermostLoop(L), AccessIdx(0),
199 ShouldRetryWithRuntimeCheck(false), SafeForVectorization(true),
200 RecordDependences(true), Preds(Preds) {}
202 /// \brief Register the location (instructions are given increasing numbers)
203 /// of a write access.
204 void addAccess(StoreInst *SI) {
205 Value *Ptr = SI->getPointerOperand();
206 Accesses[MemAccessInfo(Ptr, true)].push_back(AccessIdx);
207 InstMap.push_back(SI);
211 /// \brief Register the location (instructions are given increasing numbers)
212 /// of a write access.
213 void addAccess(LoadInst *LI) {
214 Value *Ptr = LI->getPointerOperand();
215 Accesses[MemAccessInfo(Ptr, false)].push_back(AccessIdx);
216 InstMap.push_back(LI);
220 /// \brief Check whether the dependencies between the accesses are safe.
222 /// Only checks sets with elements in \p CheckDeps.
223 bool areDepsSafe(DepCandidates &AccessSets, MemAccessInfoSet &CheckDeps,
224 const ValueToValueMap &Strides);
226 /// \brief No memory dependence was encountered that would inhibit
228 bool isSafeForVectorization() const { return SafeForVectorization; }
230 /// \brief The maximum number of bytes of a vector register we can vectorize
231 /// the accesses safely with.
232 unsigned getMaxSafeDepDistBytes() { return MaxSafeDepDistBytes; }
234 /// \brief In same cases when the dependency check fails we can still
235 /// vectorize the loop with a dynamic array access check.
236 bool shouldRetryWithRuntimeCheck() { return ShouldRetryWithRuntimeCheck; }
238 /// \brief Returns the memory dependences. If null is returned we exceeded
239 /// the MaxDependences threshold and this information is not
241 const SmallVectorImpl<Dependence> *getDependences() const {
242 return RecordDependences ? &Dependences : nullptr;
245 void clearDependences() { Dependences.clear(); }
247 /// \brief The vector of memory access instructions. The indices are used as
248 /// instruction identifiers in the Dependence class.
249 const SmallVectorImpl<Instruction *> &getMemoryInstructions() const {
253 /// \brief Find the set of instructions that read or write via \p Ptr.
254 SmallVector<Instruction *, 4> getInstructionsForAccess(Value *Ptr,
259 const Loop *InnermostLoop;
261 /// \brief Maps access locations (ptr, read/write) to program order.
262 DenseMap<MemAccessInfo, std::vector<unsigned> > Accesses;
264 /// \brief Memory access instructions in program order.
265 SmallVector<Instruction *, 16> InstMap;
267 /// \brief The program order index to be used for the next instruction.
270 // We can access this many bytes in parallel safely.
271 unsigned MaxSafeDepDistBytes;
273 /// \brief If we see a non-constant dependence distance we can still try to
274 /// vectorize this loop with runtime checks.
275 bool ShouldRetryWithRuntimeCheck;
277 /// \brief No memory dependence was encountered that would inhibit
279 bool SafeForVectorization;
281 //// \brief True if Dependences reflects the dependences in the
282 //// loop. If false we exceeded MaxDependences and
283 //// Dependences is invalid.
284 bool RecordDependences;
286 /// \brief Memory dependences collected during the analysis. Only valid if
287 /// RecordDependences is true.
288 SmallVector<Dependence, 8> Dependences;
290 /// \brief Check whether there is a plausible dependence between the two
293 /// Access \p A must happen before \p B in program order. The two indices
294 /// identify the index into the program order map.
296 /// This function checks whether there is a plausible dependence (or the
297 /// absence of such can't be proved) between the two accesses. If there is a
298 /// plausible dependence but the dependence distance is bigger than one
299 /// element access it records this distance in \p MaxSafeDepDistBytes (if this
300 /// distance is smaller than any other distance encountered so far).
301 /// Otherwise, this function returns true signaling a possible dependence.
302 Dependence::DepType isDependent(const MemAccessInfo &A, unsigned AIdx,
303 const MemAccessInfo &B, unsigned BIdx,
304 const ValueToValueMap &Strides);
306 /// \brief Check whether the data dependence could prevent store-load
308 bool couldPreventStoreLoadForward(unsigned Distance, unsigned TypeByteSize);
310 /// The SCEV predicate containing all the SCEV-related assumptions.
311 /// The dependence checker needs this in order to convert SCEVs of pointers
312 /// to more accurate expressions in the context of existing assumptions.
313 /// We also need this in case assumptions about SCEV expressions need to
314 /// be made in order to avoid unknown dependences. For example we might
315 /// assume a unit stride for a pointer in order to prove that a memory access
316 /// is strided and doesn't wrap.
317 SCEVUnionPredicate &Preds;
320 /// \brief Holds information about the memory runtime legality checks to verify
321 /// that a group of pointers do not overlap.
322 class RuntimePointerChecking {
325 /// Holds the pointer value that we need to check.
326 TrackingVH<Value> PointerValue;
327 /// Holds the pointer value at the beginning of the loop.
329 /// Holds the pointer value at the end of the loop.
331 /// Holds the information if this pointer is used for writing to memory.
333 /// Holds the id of the set of pointers that could be dependent because of a
334 /// shared underlying object.
335 unsigned DependencySetId;
336 /// Holds the id of the disjoint alias set to which this pointer belongs.
338 /// SCEV for the access.
341 PointerInfo(Value *PointerValue, const SCEV *Start, const SCEV *End,
342 bool IsWritePtr, unsigned DependencySetId, unsigned AliasSetId,
344 : PointerValue(PointerValue), Start(Start), End(End),
345 IsWritePtr(IsWritePtr), DependencySetId(DependencySetId),
346 AliasSetId(AliasSetId), Expr(Expr) {}
349 RuntimePointerChecking(ScalarEvolution *SE) : Need(false), SE(SE) {}
351 /// Reset the state of the pointer runtime information.
358 /// Insert a pointer and calculate the start and end SCEVs.
359 /// \p We need Preds in order to compute the SCEV expression of the pointer
360 /// according to the assumptions that we've made during the analysis.
361 /// The method might also version the pointer stride according to \p Strides,
362 /// and change \p Preds.
363 void insert(Loop *Lp, Value *Ptr, bool WritePtr, unsigned DepSetId,
364 unsigned ASId, const ValueToValueMap &Strides,
365 SCEVUnionPredicate &Preds);
367 /// \brief No run-time memory checking is necessary.
368 bool empty() const { return Pointers.empty(); }
370 /// A grouping of pointers. A single memcheck is required between
372 struct CheckingPtrGroup {
373 /// \brief Create a new pointer checking group containing a single
374 /// pointer, with index \p Index in RtCheck.
375 CheckingPtrGroup(unsigned Index, RuntimePointerChecking &RtCheck)
376 : RtCheck(RtCheck), High(RtCheck.Pointers[Index].End),
377 Low(RtCheck.Pointers[Index].Start) {
378 Members.push_back(Index);
381 /// \brief Tries to add the pointer recorded in RtCheck at index
382 /// \p Index to this pointer checking group. We can only add a pointer
383 /// to a checking group if we will still be able to get
384 /// the upper and lower bounds of the check. Returns true in case
385 /// of success, false otherwise.
386 bool addPointer(unsigned Index);
388 /// Constitutes the context of this pointer checking group. For each
389 /// pointer that is a member of this group we will retain the index
390 /// at which it appears in RtCheck.
391 RuntimePointerChecking &RtCheck;
392 /// The SCEV expression which represents the upper bound of all the
393 /// pointers in this group.
395 /// The SCEV expression which represents the lower bound of all the
396 /// pointers in this group.
398 /// Indices of all the pointers that constitute this grouping.
399 SmallVector<unsigned, 2> Members;
402 /// \brief A memcheck which made up of a pair of grouped pointers.
404 /// These *have* to be const for now, since checks are generated from
405 /// CheckingPtrGroups in LAI::addRuntimeChecks which is a const member
406 /// function. FIXME: once check-generation is moved inside this class (after
407 /// the PtrPartition hack is removed), we could drop const.
408 typedef std::pair<const CheckingPtrGroup *, const CheckingPtrGroup *>
411 /// \brief Generate the checks and store it. This also performs the grouping
412 /// of pointers to reduce the number of memchecks necessary.
413 void generateChecks(MemoryDepChecker::DepCandidates &DepCands,
414 bool UseDependencies);
416 /// \brief Returns the checks that generateChecks created.
417 const SmallVector<PointerCheck, 4> &getChecks() const { return Checks; }
419 /// \brief Decide if we need to add a check between two groups of pointers,
420 /// according to needsChecking.
421 bool needsChecking(const CheckingPtrGroup &M,
422 const CheckingPtrGroup &N) const;
424 /// \brief Returns the number of run-time checks required according to
426 unsigned getNumberOfChecks() const { return Checks.size(); }
428 /// \brief Print the list run-time memory checks necessary.
429 void print(raw_ostream &OS, unsigned Depth = 0) const;
432 void printChecks(raw_ostream &OS, const SmallVectorImpl<PointerCheck> &Checks,
433 unsigned Depth = 0) const;
435 /// This flag indicates if we need to add the runtime check.
438 /// Information about the pointers that may require checking.
439 SmallVector<PointerInfo, 2> Pointers;
441 /// Holds a partitioning of pointers into "check groups".
442 SmallVector<CheckingPtrGroup, 2> CheckingGroups;
444 /// \brief Check if pointers are in the same partition
446 /// \p PtrToPartition contains the partition number for pointers (-1 if the
447 /// pointer belongs to multiple partitions).
449 arePointersInSamePartition(const SmallVectorImpl<int> &PtrToPartition,
450 unsigned PtrIdx1, unsigned PtrIdx2);
452 /// \brief Decide whether we need to issue a run-time check for pointer at
453 /// index \p I and \p J to prove their independence.
454 bool needsChecking(unsigned I, unsigned J) const;
457 /// \brief Groups pointers such that a single memcheck is required
458 /// between two different groups. This will clear the CheckingGroups vector
459 /// and re-compute it. We will only group dependecies if \p UseDependencies
460 /// is true, otherwise we will create a separate group for each pointer.
461 void groupChecks(MemoryDepChecker::DepCandidates &DepCands,
462 bool UseDependencies);
464 /// Generate the checks and return them.
465 SmallVector<PointerCheck, 4>
466 generateChecks() const;
468 /// Holds a pointer to the ScalarEvolution analysis.
471 /// \brief Set of run-time checks required to establish independence of
472 /// otherwise may-aliasing pointers in the loop.
473 SmallVector<PointerCheck, 4> Checks;
476 /// \brief Drive the analysis of memory accesses in the loop
478 /// This class is responsible for analyzing the memory accesses of a loop. It
479 /// collects the accesses and then its main helper the AccessAnalysis class
480 /// finds and categorizes the dependences in buildDependenceSets.
482 /// For memory dependences that can be analyzed at compile time, it determines
483 /// whether the dependence is part of cycle inhibiting vectorization. This work
484 /// is delegated to the MemoryDepChecker class.
486 /// For memory dependences that cannot be determined at compile time, it
487 /// generates run-time checks to prove independence. This is done by
488 /// AccessAnalysis::canCheckPtrAtRT and the checks are maintained by the
489 /// RuntimePointerCheck class.
490 class LoopAccessInfo {
492 LoopAccessInfo(Loop *L, ScalarEvolution *SE, const DataLayout &DL,
493 const TargetLibraryInfo *TLI, AliasAnalysis *AA,
494 DominatorTree *DT, LoopInfo *LI,
495 const ValueToValueMap &Strides);
497 /// Return true we can analyze the memory accesses in the loop and there are
498 /// no memory dependence cycles.
499 bool canVectorizeMemory() const { return CanVecMem; }
501 const RuntimePointerChecking *getRuntimePointerChecking() const {
502 return &PtrRtChecking;
505 /// \brief Number of memchecks required to prove independence of otherwise
506 /// may-alias pointers.
507 unsigned getNumRuntimePointerChecks() const {
508 return PtrRtChecking.getNumberOfChecks();
511 /// Return true if the block BB needs to be predicated in order for the loop
512 /// to be vectorized.
513 static bool blockNeedsPredication(BasicBlock *BB, Loop *TheLoop,
516 /// Returns true if the value V is uniform within the loop.
517 bool isUniform(Value *V) const;
519 unsigned getMaxSafeDepDistBytes() const { return MaxSafeDepDistBytes; }
520 unsigned getNumStores() const { return NumStores; }
521 unsigned getNumLoads() const { return NumLoads;}
523 /// \brief Add code that checks at runtime if the accessed arrays overlap.
525 /// Returns a pair of instructions where the first element is the first
526 /// instruction generated in possibly a sequence of instructions and the
527 /// second value is the final comparator value or NULL if no check is needed.
528 std::pair<Instruction *, Instruction *>
529 addRuntimeChecks(Instruction *Loc) const;
531 /// \brief Generete the instructions for the checks in \p PointerChecks.
533 /// Returns a pair of instructions where the first element is the first
534 /// instruction generated in possibly a sequence of instructions and the
535 /// second value is the final comparator value or NULL if no check is needed.
536 std::pair<Instruction *, Instruction *>
537 addRuntimeChecks(Instruction *Loc,
538 const SmallVectorImpl<RuntimePointerChecking::PointerCheck>
539 &PointerChecks) const;
541 /// \brief The diagnostics report generated for the analysis. E.g. why we
542 /// couldn't analyze the loop.
543 const Optional<LoopAccessReport> &getReport() const { return Report; }
545 /// \brief the Memory Dependence Checker which can determine the
546 /// loop-independent and loop-carried dependences between memory accesses.
547 const MemoryDepChecker &getDepChecker() const { return DepChecker; }
549 /// \brief Return the list of instructions that use \p Ptr to read or write
551 SmallVector<Instruction *, 4> getInstructionsForAccess(Value *Ptr,
552 bool isWrite) const {
553 return DepChecker.getInstructionsForAccess(Ptr, isWrite);
556 /// \brief Print the information about the memory accesses in the loop.
557 void print(raw_ostream &OS, unsigned Depth = 0) const;
559 /// \brief Used to ensure that if the analysis was run with speculating the
560 /// value of symbolic strides, the client queries it with the same assumption.
561 /// Only used in DEBUG build but we don't want NDEBUG-dependent ABI.
562 unsigned NumSymbolicStrides;
564 /// \brief Checks existence of store to invariant address inside loop.
565 /// If the loop has any store to invariant address, then it returns true,
566 /// else returns false.
567 bool hasStoreToLoopInvariantAddress() const {
568 return StoreToLoopInvariantAddress;
571 /// The SCEV predicate contains all the SCEV-related assumptions.
572 /// The is used to keep track of the minimal set of assumptions on SCEV
573 /// expressions that the analysis needs to make in order to return a
574 /// meaningful result. All SCEV expressions during the analysis should be
575 /// re-written (and therefore simplified) according to Preds.
576 /// A user of LoopAccessAnalysis will need to emit the runtime checks
577 /// associated with this predicate.
578 SCEVUnionPredicate Preds;
581 /// \brief Analyze the loop. Substitute symbolic strides using Strides.
582 void analyzeLoop(const ValueToValueMap &Strides);
584 /// \brief Check if the structure of the loop allows it to be analyzed by this
586 bool canAnalyzeLoop();
588 void emitAnalysis(LoopAccessReport &Message);
590 /// We need to check that all of the pointers in this list are disjoint
592 RuntimePointerChecking PtrRtChecking;
594 /// \brief the Memory Dependence Checker which can determine the
595 /// loop-independent and loop-carried dependences between memory accesses.
596 MemoryDepChecker DepChecker;
600 const DataLayout &DL;
601 const TargetLibraryInfo *TLI;
609 unsigned MaxSafeDepDistBytes;
611 /// \brief Cache the result of analyzeLoop.
614 /// \brief Indicator for storing to uniform addresses.
615 /// If a loop has write to a loop invariant address then it should be true.
616 bool StoreToLoopInvariantAddress;
618 /// \brief The diagnostics report generated for the analysis. E.g. why we
619 /// couldn't analyze the loop.
620 Optional<LoopAccessReport> Report;
623 Value *stripIntegerCast(Value *V);
625 ///\brief Return the SCEV corresponding to a pointer with the symbolic stride
626 /// replaced with constant one, assuming \p Preds is true.
628 /// If necessary this method will version the stride of the pointer according
629 /// to \p PtrToStride and therefore add a new predicate to \p Preds.
631 /// If \p OrigPtr is not null, use it to look up the stride value instead of \p
632 /// Ptr. \p PtrToStride provides the mapping between the pointer value and its
633 /// stride as collected by LoopVectorizationLegality::collectStridedAccess.
634 const SCEV *replaceSymbolicStrideSCEV(ScalarEvolution *SE,
635 const ValueToValueMap &PtrToStride,
636 SCEVUnionPredicate &Preds, Value *Ptr,
637 Value *OrigPtr = nullptr);
639 /// \brief Check the stride of the pointer and ensure that it does not wrap in
640 /// the address space, assuming \p Preds is true.
642 /// If necessary this method will version the stride of the pointer according
643 /// to \p PtrToStride and therefore add a new predicate to \p Preds.
644 int isStridedPtr(ScalarEvolution *SE, Value *Ptr, const Loop *Lp,
645 const ValueToValueMap &StridesMap, SCEVUnionPredicate &Preds);
647 /// \brief This analysis provides dependence information for the memory accesses
650 /// It runs the analysis for a loop on demand. This can be initiated by
651 /// querying the loop access info via LAA::getInfo. getInfo return a
652 /// LoopAccessInfo object. See this class for the specifics of what information
654 class LoopAccessAnalysis : public FunctionPass {
658 LoopAccessAnalysis() : FunctionPass(ID) {
659 initializeLoopAccessAnalysisPass(*PassRegistry::getPassRegistry());
662 bool runOnFunction(Function &F) override;
664 void getAnalysisUsage(AnalysisUsage &AU) const override;
666 /// \brief Query the result of the loop access information for the loop \p L.
668 /// If the client speculates (and then issues run-time checks) for the values
669 /// of symbolic strides, \p Strides provides the mapping (see
670 /// replaceSymbolicStrideSCEV). If there is no cached result available run
672 const LoopAccessInfo &getInfo(Loop *L, const ValueToValueMap &Strides);
674 void releaseMemory() override {
675 // Invalidate the cache when the pass is freed.
676 LoopAccessInfoMap.clear();
679 /// \brief Print the result of the analysis when invoked with -analyze.
680 void print(raw_ostream &OS, const Module *M = nullptr) const override;
683 /// \brief The cache.
684 DenseMap<Loop *, std::unique_ptr<LoopAccessInfo>> LoopAccessInfoMap;
686 // The used analysis passes.
688 const TargetLibraryInfo *TLI;
694 inline Instruction *MemoryDepChecker::Dependence::getSource(
695 const LoopAccessInfo &LAI) const {
696 return LAI.getDepChecker().getMemoryInstructions()[Source];
699 inline Instruction *MemoryDepChecker::Dependence::getDestination(
700 const LoopAccessInfo &LAI) const {
701 return LAI.getDepChecker().getMemoryInstructions()[Destination];
704 } // End llvm namespace