1 //===- MemoryDependenceAnalysis.cpp - Mem Deps Implementation --*- 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 implements an analysis that determines, for a given memory
11 // operation, what preceding memory operations it depends on. It builds on
12 // alias analysis information, and tries to provide a lazy, caching interface to
13 // a common kind of alias information query.
15 //===----------------------------------------------------------------------===//
17 #define DEBUG_TYPE "memdep"
18 #include "llvm/Analysis/MemoryDependenceAnalysis.h"
19 #include "llvm/Instructions.h"
20 #include "llvm/IntrinsicInst.h"
21 #include "llvm/Function.h"
22 #include "llvm/LLVMContext.h"
23 #include "llvm/Analysis/AliasAnalysis.h"
24 #include "llvm/Analysis/Dominators.h"
25 #include "llvm/Analysis/InstructionSimplify.h"
26 #include "llvm/Analysis/MemoryBuiltins.h"
27 #include "llvm/Analysis/PHITransAddr.h"
28 #include "llvm/ADT/Statistic.h"
29 #include "llvm/ADT/STLExtras.h"
30 #include "llvm/Support/PredIteratorCache.h"
31 #include "llvm/Support/Debug.h"
34 STATISTIC(NumCacheNonLocal, "Number of fully cached non-local responses");
35 STATISTIC(NumCacheDirtyNonLocal, "Number of dirty cached non-local responses");
36 STATISTIC(NumUncacheNonLocal, "Number of uncached non-local responses");
38 STATISTIC(NumCacheNonLocalPtr,
39 "Number of fully cached non-local ptr responses");
40 STATISTIC(NumCacheDirtyNonLocalPtr,
41 "Number of cached, but dirty, non-local ptr responses");
42 STATISTIC(NumUncacheNonLocalPtr,
43 "Number of uncached non-local ptr responses");
44 STATISTIC(NumCacheCompleteNonLocalPtr,
45 "Number of block queries that were completely cached");
47 char MemoryDependenceAnalysis::ID = 0;
49 // Register this pass...
50 INITIALIZE_PASS_BEGIN(MemoryDependenceAnalysis, "memdep",
51 "Memory Dependence Analysis", false, true)
52 INITIALIZE_AG_DEPENDENCY(AliasAnalysis)
53 INITIALIZE_PASS_END(MemoryDependenceAnalysis, "memdep",
54 "Memory Dependence Analysis", false, true)
56 MemoryDependenceAnalysis::MemoryDependenceAnalysis()
57 : FunctionPass(ID), PredCache(0) {
58 initializeMemoryDependenceAnalysisPass(*PassRegistry::getPassRegistry());
60 MemoryDependenceAnalysis::~MemoryDependenceAnalysis() {
63 /// Clean up memory in between runs
64 void MemoryDependenceAnalysis::releaseMemory() {
67 NonLocalPointerDeps.clear();
68 ReverseLocalDeps.clear();
69 ReverseNonLocalDeps.clear();
70 ReverseNonLocalPtrDeps.clear();
76 /// getAnalysisUsage - Does not modify anything. It uses Alias Analysis.
78 void MemoryDependenceAnalysis::getAnalysisUsage(AnalysisUsage &AU) const {
80 AU.addRequiredTransitive<AliasAnalysis>();
83 bool MemoryDependenceAnalysis::runOnFunction(Function &) {
84 AA = &getAnalysis<AliasAnalysis>();
86 PredCache.reset(new PredIteratorCache());
90 /// RemoveFromReverseMap - This is a helper function that removes Val from
91 /// 'Inst's set in ReverseMap. If the set becomes empty, remove Inst's entry.
92 template <typename KeyTy>
93 static void RemoveFromReverseMap(DenseMap<Instruction*,
94 SmallPtrSet<KeyTy, 4> > &ReverseMap,
95 Instruction *Inst, KeyTy Val) {
96 typename DenseMap<Instruction*, SmallPtrSet<KeyTy, 4> >::iterator
97 InstIt = ReverseMap.find(Inst);
98 assert(InstIt != ReverseMap.end() && "Reverse map out of sync?");
99 bool Found = InstIt->second.erase(Val);
100 assert(Found && "Invalid reverse map!"); Found=Found;
101 if (InstIt->second.empty())
102 ReverseMap.erase(InstIt);
106 /// getCallSiteDependencyFrom - Private helper for finding the local
107 /// dependencies of a call site.
108 MemDepResult MemoryDependenceAnalysis::
109 getCallSiteDependencyFrom(CallSite CS, bool isReadOnlyCall,
110 BasicBlock::iterator ScanIt, BasicBlock *BB) {
111 // Walk backwards through the block, looking for dependencies
112 while (ScanIt != BB->begin()) {
113 Instruction *Inst = --ScanIt;
115 // If this inst is a memory op, get the pointer it accessed
116 AliasAnalysis::Location Loc;
117 if (StoreInst *S = dyn_cast<StoreInst>(Inst)) {
118 Loc = AliasAnalysis::Location(S->getPointerOperand(),
119 AA->getTypeStoreSize(S->getValueOperand()
121 S->getMetadata(LLVMContext::MD_tbaa));
122 } else if (VAArgInst *V = dyn_cast<VAArgInst>(Inst)) {
123 Loc = AliasAnalysis::Location(V->getPointerOperand(),
124 AA->getTypeStoreSize(V->getType()),
125 V->getMetadata(LLVMContext::MD_tbaa));
126 } else if (const CallInst *CI = isFreeCall(Inst)) {
127 // calls to free() erase the entire structure
128 Loc = AliasAnalysis::Location(CI->getArgOperand(0));
129 } else if (CallSite InstCS = cast<Value>(Inst)) {
130 // Debug intrinsics don't cause dependences.
131 if (isa<DbgInfoIntrinsic>(Inst)) continue;
132 // If these two calls do not interfere, look past it.
133 switch (AA->getModRefInfo(CS, InstCS)) {
134 case AliasAnalysis::NoModRef:
135 // If the two calls are the same, return InstCS as a Def, so that
136 // CS can be found redundant and eliminated.
137 if (isReadOnlyCall && InstCS.onlyReadsMemory() &&
138 CS.getInstruction()->isIdenticalToWhenDefined(Inst))
139 return MemDepResult::getDef(Inst);
141 // Otherwise if the two calls don't interact (e.g. InstCS is readnone)
145 return MemDepResult::getClobber(Inst);
148 // Non-memory instruction.
152 if (AA->getModRefInfo(CS, Loc) != AliasAnalysis::NoModRef)
153 return MemDepResult::getClobber(Inst);
156 // No dependence found. If this is the entry block of the function, it is a
157 // clobber, otherwise it is non-local.
158 if (BB != &BB->getParent()->getEntryBlock())
159 return MemDepResult::getNonLocal();
160 return MemDepResult::getClobber(ScanIt);
163 /// getPointerDependencyFrom - Return the instruction on which a memory
164 /// location depends. If isLoad is true, this routine ignores may-aliases with
165 /// read-only operations. If isLoad is false, this routine ignores may-aliases
166 /// with reads from read-only locations.
167 MemDepResult MemoryDependenceAnalysis::
168 getPointerDependencyFrom(const AliasAnalysis::Location &MemLoc, bool isLoad,
169 BasicBlock::iterator ScanIt, BasicBlock *BB) {
171 Value *InvariantTag = 0;
173 // Walk backwards through the basic block, looking for dependencies.
174 while (ScanIt != BB->begin()) {
175 Instruction *Inst = --ScanIt;
177 // If we're in an invariant region, no dependencies can be found before
178 // we pass an invariant-begin marker.
179 if (InvariantTag == Inst) {
184 if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(Inst)) {
185 // Debug intrinsics don't (and can't) cause dependences.
186 if (isa<DbgInfoIntrinsic>(II)) continue;
188 // If we pass an invariant-end marker, then we've just entered an
189 // invariant region and can start ignoring dependencies.
190 if (II->getIntrinsicID() == Intrinsic::invariant_end) {
191 // FIXME: This only considers queries directly on the invariant-tagged
192 // pointer, not on query pointers that are indexed off of them. It'd
193 // be nice to handle that at some point.
194 AliasAnalysis::AliasResult R =
195 AA->alias(AliasAnalysis::Location(II->getArgOperand(2)), MemLoc);
196 if (R == AliasAnalysis::MustAlias)
197 InvariantTag = II->getArgOperand(0);
202 // If we reach a lifetime begin or end marker, then the query ends here
203 // because the value is undefined.
204 if (II->getIntrinsicID() == Intrinsic::lifetime_start) {
205 // FIXME: This only considers queries directly on the invariant-tagged
206 // pointer, not on query pointers that are indexed off of them. It'd
207 // be nice to handle that at some point.
208 AliasAnalysis::AliasResult R =
209 AA->alias(AliasAnalysis::Location(II->getArgOperand(1)), MemLoc);
210 if (R == AliasAnalysis::MustAlias)
211 return MemDepResult::getDef(II);
216 // If we're querying on a load and we're in an invariant region, we're done
217 // at this point. Nothing a load depends on can live in an invariant region.
219 // FIXME: this will prevent us from returning load/load must-aliases, so GVN
220 // won't remove redundant loads.
221 if (isLoad && InvariantTag) continue;
223 // Values depend on loads if the pointers are must aliased. This means that
224 // a load depends on another must aliased load from the same value.
225 if (LoadInst *LI = dyn_cast<LoadInst>(Inst)) {
226 Value *Pointer = LI->getPointerOperand();
227 uint64_t PointerSize = AA->getTypeStoreSize(LI->getType());
228 MDNode *TBAATag = LI->getMetadata(LLVMContext::MD_tbaa);
229 AliasAnalysis::Location LoadLoc(Pointer, PointerSize, TBAATag);
231 // If we found a pointer, check if it could be the same as our pointer.
232 AliasAnalysis::AliasResult R = AA->alias(LoadLoc, MemLoc);
233 if (R == AliasAnalysis::NoAlias)
236 // May-alias loads don't depend on each other without a dependence.
237 if (isLoad && R == AliasAnalysis::MayAlias)
240 // Stores don't alias loads from read-only memory.
241 if (!isLoad && AA->pointsToConstantMemory(LoadLoc))
244 // Stores depend on may and must aliased loads, loads depend on must-alias
246 return MemDepResult::getDef(Inst);
249 if (StoreInst *SI = dyn_cast<StoreInst>(Inst)) {
250 // There can't be stores to the value we care about inside an
252 if (InvariantTag) continue;
254 // If alias analysis can tell that this store is guaranteed to not modify
255 // the query pointer, ignore it. Use getModRefInfo to handle cases where
256 // the query pointer points to constant memory etc.
257 if (AA->getModRefInfo(SI, MemLoc) == AliasAnalysis::NoModRef)
260 // Ok, this store might clobber the query pointer. Check to see if it is
261 // a must alias: in this case, we want to return this as a def.
262 Value *Pointer = SI->getPointerOperand();
263 uint64_t PointerSize = AA->getTypeStoreSize(SI->getOperand(0)->getType());
264 MDNode *TBAATag = SI->getMetadata(LLVMContext::MD_tbaa);
266 // If we found a pointer, check if it could be the same as our pointer.
267 AliasAnalysis::AliasResult R =
268 AA->alias(AliasAnalysis::Location(Pointer, PointerSize, TBAATag),
271 if (R == AliasAnalysis::NoAlias)
273 if (R == AliasAnalysis::MayAlias)
274 return MemDepResult::getClobber(Inst);
275 return MemDepResult::getDef(Inst);
278 // If this is an allocation, and if we know that the accessed pointer is to
279 // the allocation, return Def. This means that there is no dependence and
280 // the access can be optimized based on that. For example, a load could
282 // Note: Only determine this to be a malloc if Inst is the malloc call, not
283 // a subsequent bitcast of the malloc call result. There can be stores to
284 // the malloced memory between the malloc call and its bitcast uses, and we
285 // need to continue scanning until the malloc call.
286 if (isa<AllocaInst>(Inst) ||
287 (isa<CallInst>(Inst) && extractMallocCall(Inst))) {
288 const Value *AccessPtr = MemLoc.Ptr->getUnderlyingObject();
290 if (AccessPtr == Inst ||
291 AA->alias(Inst, 1, AccessPtr, 1) == AliasAnalysis::MustAlias)
292 return MemDepResult::getDef(Inst);
296 // See if this instruction (e.g. a call or vaarg) mod/ref's the pointer.
297 switch (AA->getModRefInfo(Inst, MemLoc)) {
298 case AliasAnalysis::NoModRef:
299 // If the call has no effect on the queried pointer, just ignore it.
301 case AliasAnalysis::Mod:
302 // If we're in an invariant region, we can ignore calls that ONLY
303 // modify the pointer.
304 if (InvariantTag) continue;
305 return MemDepResult::getClobber(Inst);
306 case AliasAnalysis::Ref:
307 // If the call is known to never store to the pointer, and if this is a
308 // load query, we can safely ignore it (scan past it).
312 // Otherwise, there is a potential dependence. Return a clobber.
313 return MemDepResult::getClobber(Inst);
317 // No dependence found. If this is the entry block of the function, it is a
318 // clobber, otherwise it is non-local.
319 if (BB != &BB->getParent()->getEntryBlock())
320 return MemDepResult::getNonLocal();
321 return MemDepResult::getClobber(ScanIt);
324 /// getDependency - Return the instruction on which a memory operation
326 MemDepResult MemoryDependenceAnalysis::getDependency(Instruction *QueryInst) {
327 Instruction *ScanPos = QueryInst;
329 // Check for a cached result
330 MemDepResult &LocalCache = LocalDeps[QueryInst];
332 // If the cached entry is non-dirty, just return it. Note that this depends
333 // on MemDepResult's default constructing to 'dirty'.
334 if (!LocalCache.isDirty())
337 // Otherwise, if we have a dirty entry, we know we can start the scan at that
338 // instruction, which may save us some work.
339 if (Instruction *Inst = LocalCache.getInst()) {
342 RemoveFromReverseMap(ReverseLocalDeps, Inst, QueryInst);
345 BasicBlock *QueryParent = QueryInst->getParent();
347 AliasAnalysis::Location MemLoc;
350 if (BasicBlock::iterator(QueryInst) == QueryParent->begin()) {
351 // No dependence found. If this is the entry block of the function, it is a
352 // clobber, otherwise it is non-local.
353 if (QueryParent != &QueryParent->getParent()->getEntryBlock())
354 LocalCache = MemDepResult::getNonLocal();
356 LocalCache = MemDepResult::getClobber(QueryInst);
357 } else if (StoreInst *SI = dyn_cast<StoreInst>(QueryInst)) {
358 // If this is a volatile store, don't mess around with it. Just return the
359 // previous instruction as a clobber.
360 if (SI->isVolatile())
361 LocalCache = MemDepResult::getClobber(--BasicBlock::iterator(ScanPos));
363 MemLoc = AliasAnalysis::Location(SI->getPointerOperand(),
364 AA->getTypeStoreSize(SI->getOperand(0)
366 SI->getMetadata(LLVMContext::MD_tbaa));
367 } else if (LoadInst *LI = dyn_cast<LoadInst>(QueryInst)) {
368 // If this is a volatile load, don't mess around with it. Just return the
369 // previous instruction as a clobber.
370 if (LI->isVolatile())
371 LocalCache = MemDepResult::getClobber(--BasicBlock::iterator(ScanPos));
373 MemLoc = AliasAnalysis::Location(LI->getPointerOperand(),
374 AA->getTypeStoreSize(LI->getType()),
375 LI->getMetadata(LLVMContext::MD_tbaa));
376 } else if (const CallInst *CI = isFreeCall(QueryInst)) {
377 // calls to free() erase the entire structure, not just a field.
378 MemLoc = AliasAnalysis::Location(CI->getArgOperand(0));
379 } else if (isa<CallInst>(QueryInst) || isa<InvokeInst>(QueryInst)) {
380 int IntrinsicID = 0; // Intrinsic IDs start at 1.
381 IntrinsicInst *II = dyn_cast<IntrinsicInst>(QueryInst);
383 IntrinsicID = II->getIntrinsicID();
385 switch (IntrinsicID) {
386 case Intrinsic::lifetime_start:
387 case Intrinsic::lifetime_end:
388 case Intrinsic::invariant_start:
389 MemLoc = AliasAnalysis::Location(II->getArgOperand(1),
390 cast<ConstantInt>(II->getArgOperand(0))
392 II->getMetadata(LLVMContext::MD_tbaa));
394 case Intrinsic::invariant_end:
395 MemLoc = AliasAnalysis::Location(II->getArgOperand(2),
396 cast<ConstantInt>(II->getArgOperand(1))
398 II->getMetadata(LLVMContext::MD_tbaa));
401 CallSite QueryCS(QueryInst);
402 bool isReadOnly = AA->onlyReadsMemory(QueryCS);
403 LocalCache = getCallSiteDependencyFrom(QueryCS, isReadOnly, ScanPos,
408 // Non-memory instruction.
409 LocalCache = MemDepResult::getClobber(--BasicBlock::iterator(ScanPos));
412 // If we need to do a pointer scan, make it happen.
414 bool isLoad = !QueryInst->mayWriteToMemory();
415 if (IntrinsicInst *II = dyn_cast<MemoryUseIntrinsic>(QueryInst)) {
416 isLoad |= II->getIntrinsicID() == Intrinsic::lifetime_end;
418 LocalCache = getPointerDependencyFrom(MemLoc, isLoad, ScanPos,
422 // Remember the result!
423 if (Instruction *I = LocalCache.getInst())
424 ReverseLocalDeps[I].insert(QueryInst);
430 /// AssertSorted - This method is used when -debug is specified to verify that
431 /// cache arrays are properly kept sorted.
432 static void AssertSorted(MemoryDependenceAnalysis::NonLocalDepInfo &Cache,
434 if (Count == -1) Count = Cache.size();
435 if (Count == 0) return;
437 for (unsigned i = 1; i != unsigned(Count); ++i)
438 assert(!(Cache[i] < Cache[i-1]) && "Cache isn't sorted!");
442 /// getNonLocalCallDependency - Perform a full dependency query for the
443 /// specified call, returning the set of blocks that the value is
444 /// potentially live across. The returned set of results will include a
445 /// "NonLocal" result for all blocks where the value is live across.
447 /// This method assumes the instruction returns a "NonLocal" dependency
448 /// within its own block.
450 /// This returns a reference to an internal data structure that may be
451 /// invalidated on the next non-local query or when an instruction is
452 /// removed. Clients must copy this data if they want it around longer than
454 const MemoryDependenceAnalysis::NonLocalDepInfo &
455 MemoryDependenceAnalysis::getNonLocalCallDependency(CallSite QueryCS) {
456 assert(getDependency(QueryCS.getInstruction()).isNonLocal() &&
457 "getNonLocalCallDependency should only be used on calls with non-local deps!");
458 PerInstNLInfo &CacheP = NonLocalDeps[QueryCS.getInstruction()];
459 NonLocalDepInfo &Cache = CacheP.first;
461 /// DirtyBlocks - This is the set of blocks that need to be recomputed. In
462 /// the cached case, this can happen due to instructions being deleted etc. In
463 /// the uncached case, this starts out as the set of predecessors we care
465 SmallVector<BasicBlock*, 32> DirtyBlocks;
467 if (!Cache.empty()) {
468 // Okay, we have a cache entry. If we know it is not dirty, just return it
469 // with no computation.
470 if (!CacheP.second) {
475 // If we already have a partially computed set of results, scan them to
476 // determine what is dirty, seeding our initial DirtyBlocks worklist.
477 for (NonLocalDepInfo::iterator I = Cache.begin(), E = Cache.end();
479 if (I->getResult().isDirty())
480 DirtyBlocks.push_back(I->getBB());
482 // Sort the cache so that we can do fast binary search lookups below.
483 std::sort(Cache.begin(), Cache.end());
485 ++NumCacheDirtyNonLocal;
486 //cerr << "CACHED CASE: " << DirtyBlocks.size() << " dirty: "
487 // << Cache.size() << " cached: " << *QueryInst;
489 // Seed DirtyBlocks with each of the preds of QueryInst's block.
490 BasicBlock *QueryBB = QueryCS.getInstruction()->getParent();
491 for (BasicBlock **PI = PredCache->GetPreds(QueryBB); *PI; ++PI)
492 DirtyBlocks.push_back(*PI);
493 ++NumUncacheNonLocal;
496 // isReadonlyCall - If this is a read-only call, we can be more aggressive.
497 bool isReadonlyCall = AA->onlyReadsMemory(QueryCS);
499 SmallPtrSet<BasicBlock*, 64> Visited;
501 unsigned NumSortedEntries = Cache.size();
502 DEBUG(AssertSorted(Cache));
504 // Iterate while we still have blocks to update.
505 while (!DirtyBlocks.empty()) {
506 BasicBlock *DirtyBB = DirtyBlocks.back();
507 DirtyBlocks.pop_back();
509 // Already processed this block?
510 if (!Visited.insert(DirtyBB))
513 // Do a binary search to see if we already have an entry for this block in
514 // the cache set. If so, find it.
515 DEBUG(AssertSorted(Cache, NumSortedEntries));
516 NonLocalDepInfo::iterator Entry =
517 std::upper_bound(Cache.begin(), Cache.begin()+NumSortedEntries,
518 NonLocalDepEntry(DirtyBB));
519 if (Entry != Cache.begin() && prior(Entry)->getBB() == DirtyBB)
522 NonLocalDepEntry *ExistingResult = 0;
523 if (Entry != Cache.begin()+NumSortedEntries &&
524 Entry->getBB() == DirtyBB) {
525 // If we already have an entry, and if it isn't already dirty, the block
527 if (!Entry->getResult().isDirty())
530 // Otherwise, remember this slot so we can update the value.
531 ExistingResult = &*Entry;
534 // If the dirty entry has a pointer, start scanning from it so we don't have
535 // to rescan the entire block.
536 BasicBlock::iterator ScanPos = DirtyBB->end();
537 if (ExistingResult) {
538 if (Instruction *Inst = ExistingResult->getResult().getInst()) {
540 // We're removing QueryInst's use of Inst.
541 RemoveFromReverseMap(ReverseNonLocalDeps, Inst,
542 QueryCS.getInstruction());
546 // Find out if this block has a local dependency for QueryInst.
549 if (ScanPos != DirtyBB->begin()) {
550 Dep = getCallSiteDependencyFrom(QueryCS, isReadonlyCall,ScanPos, DirtyBB);
551 } else if (DirtyBB != &DirtyBB->getParent()->getEntryBlock()) {
552 // No dependence found. If this is the entry block of the function, it is
553 // a clobber, otherwise it is non-local.
554 Dep = MemDepResult::getNonLocal();
556 Dep = MemDepResult::getClobber(ScanPos);
559 // If we had a dirty entry for the block, update it. Otherwise, just add
562 ExistingResult->setResult(Dep);
564 Cache.push_back(NonLocalDepEntry(DirtyBB, Dep));
566 // If the block has a dependency (i.e. it isn't completely transparent to
567 // the value), remember the association!
568 if (!Dep.isNonLocal()) {
569 // Keep the ReverseNonLocalDeps map up to date so we can efficiently
570 // update this when we remove instructions.
571 if (Instruction *Inst = Dep.getInst())
572 ReverseNonLocalDeps[Inst].insert(QueryCS.getInstruction());
575 // If the block *is* completely transparent to the load, we need to check
576 // the predecessors of this block. Add them to our worklist.
577 for (BasicBlock **PI = PredCache->GetPreds(DirtyBB); *PI; ++PI)
578 DirtyBlocks.push_back(*PI);
585 /// getNonLocalPointerDependency - Perform a full dependency query for an
586 /// access to the specified (non-volatile) memory location, returning the
587 /// set of instructions that either define or clobber the value.
589 /// This method assumes the pointer has a "NonLocal" dependency within its
592 void MemoryDependenceAnalysis::
593 getNonLocalPointerDependency(const AliasAnalysis::Location &Loc, bool isLoad,
595 SmallVectorImpl<NonLocalDepResult> &Result) {
596 assert(Loc.Ptr->getType()->isPointerTy() &&
597 "Can't get pointer deps of a non-pointer!");
600 PHITransAddr Address(const_cast<Value *>(Loc.Ptr), TD);
602 // This is the set of blocks we've inspected, and the pointer we consider in
603 // each block. Because of critical edges, we currently bail out if querying
604 // a block with multiple different pointers. This can happen during PHI
606 DenseMap<BasicBlock*, Value*> Visited;
607 if (!getNonLocalPointerDepFromBB(Address, Loc, isLoad, FromBB,
608 Result, Visited, true))
611 Result.push_back(NonLocalDepResult(FromBB,
612 MemDepResult::getClobber(FromBB->begin()),
613 const_cast<Value *>(Loc.Ptr)));
616 /// GetNonLocalInfoForBlock - Compute the memdep value for BB with
617 /// Pointer/PointeeSize using either cached information in Cache or by doing a
618 /// lookup (which may use dirty cache info if available). If we do a lookup,
619 /// add the result to the cache.
620 MemDepResult MemoryDependenceAnalysis::
621 GetNonLocalInfoForBlock(const AliasAnalysis::Location &Loc,
622 bool isLoad, BasicBlock *BB,
623 NonLocalDepInfo *Cache, unsigned NumSortedEntries) {
625 // Do a binary search to see if we already have an entry for this block in
626 // the cache set. If so, find it.
627 NonLocalDepInfo::iterator Entry =
628 std::upper_bound(Cache->begin(), Cache->begin()+NumSortedEntries,
629 NonLocalDepEntry(BB));
630 if (Entry != Cache->begin() && (Entry-1)->getBB() == BB)
633 NonLocalDepEntry *ExistingResult = 0;
634 if (Entry != Cache->begin()+NumSortedEntries && Entry->getBB() == BB)
635 ExistingResult = &*Entry;
637 // If we have a cached entry, and it is non-dirty, use it as the value for
639 if (ExistingResult && !ExistingResult->getResult().isDirty()) {
640 ++NumCacheNonLocalPtr;
641 return ExistingResult->getResult();
644 // Otherwise, we have to scan for the value. If we have a dirty cache
645 // entry, start scanning from its position, otherwise we scan from the end
647 BasicBlock::iterator ScanPos = BB->end();
648 if (ExistingResult && ExistingResult->getResult().getInst()) {
649 assert(ExistingResult->getResult().getInst()->getParent() == BB &&
650 "Instruction invalidated?");
651 ++NumCacheDirtyNonLocalPtr;
652 ScanPos = ExistingResult->getResult().getInst();
654 // Eliminating the dirty entry from 'Cache', so update the reverse info.
655 ValueIsLoadPair CacheKey(Loc.Ptr, isLoad);
656 RemoveFromReverseMap(ReverseNonLocalPtrDeps, ScanPos, CacheKey);
658 ++NumUncacheNonLocalPtr;
661 // Scan the block for the dependency.
662 MemDepResult Dep = getPointerDependencyFrom(Loc, isLoad, ScanPos, BB);
664 // If we had a dirty entry for the block, update it. Otherwise, just add
667 ExistingResult->setResult(Dep);
669 Cache->push_back(NonLocalDepEntry(BB, Dep));
671 // If the block has a dependency (i.e. it isn't completely transparent to
672 // the value), remember the reverse association because we just added it
674 if (Dep.isNonLocal())
677 // Keep the ReverseNonLocalPtrDeps map up to date so we can efficiently
678 // update MemDep when we remove instructions.
679 Instruction *Inst = Dep.getInst();
680 assert(Inst && "Didn't depend on anything?");
681 ValueIsLoadPair CacheKey(Loc.Ptr, isLoad);
682 ReverseNonLocalPtrDeps[Inst].insert(CacheKey);
686 /// SortNonLocalDepInfoCache - Sort the a NonLocalDepInfo cache, given a certain
687 /// number of elements in the array that are already properly ordered. This is
688 /// optimized for the case when only a few entries are added.
690 SortNonLocalDepInfoCache(MemoryDependenceAnalysis::NonLocalDepInfo &Cache,
691 unsigned NumSortedEntries) {
692 switch (Cache.size() - NumSortedEntries) {
694 // done, no new entries.
697 // Two new entries, insert the last one into place.
698 NonLocalDepEntry Val = Cache.back();
700 MemoryDependenceAnalysis::NonLocalDepInfo::iterator Entry =
701 std::upper_bound(Cache.begin(), Cache.end()-1, Val);
702 Cache.insert(Entry, Val);
706 // One new entry, Just insert the new value at the appropriate position.
707 if (Cache.size() != 1) {
708 NonLocalDepEntry Val = Cache.back();
710 MemoryDependenceAnalysis::NonLocalDepInfo::iterator Entry =
711 std::upper_bound(Cache.begin(), Cache.end(), Val);
712 Cache.insert(Entry, Val);
716 // Added many values, do a full scale sort.
717 std::sort(Cache.begin(), Cache.end());
722 /// getNonLocalPointerDepFromBB - Perform a dependency query based on
723 /// pointer/pointeesize starting at the end of StartBB. Add any clobber/def
724 /// results to the results vector and keep track of which blocks are visited in
727 /// This has special behavior for the first block queries (when SkipFirstBlock
728 /// is true). In this special case, it ignores the contents of the specified
729 /// block and starts returning dependence info for its predecessors.
731 /// This function returns false on success, or true to indicate that it could
732 /// not compute dependence information for some reason. This should be treated
733 /// as a clobber dependence on the first instruction in the predecessor block.
734 bool MemoryDependenceAnalysis::
735 getNonLocalPointerDepFromBB(const PHITransAddr &Pointer,
736 const AliasAnalysis::Location &Loc,
737 bool isLoad, BasicBlock *StartBB,
738 SmallVectorImpl<NonLocalDepResult> &Result,
739 DenseMap<BasicBlock*, Value*> &Visited,
740 bool SkipFirstBlock) {
742 // Look up the cached info for Pointer.
743 ValueIsLoadPair CacheKey(Pointer.getAddr(), isLoad);
745 // Set up a temporary NLPI value. If the map doesn't yet have an entry for
746 // CacheKey, this value will be inserted as the associated value. Otherwise,
747 // it'll be ignored, and we'll have to check to see if the cached size and
748 // tbaa tag are consistent with the current query.
749 NonLocalPointerInfo InitialNLPI;
750 InitialNLPI.Size = Loc.Size;
751 InitialNLPI.TBAATag = Loc.TBAATag;
753 // Get the NLPI for CacheKey, inserting one into the map if it doesn't
755 std::pair<CachedNonLocalPointerInfo::iterator, bool> Pair =
756 NonLocalPointerDeps.insert(std::make_pair(CacheKey, InitialNLPI));
757 NonLocalPointerInfo *CacheInfo = &Pair.first->second;
759 // If we already have a cache entry for this CacheKey, we may need to do some
760 // work to reconcile the cache entry and the current query.
762 if (CacheInfo->Size < Loc.Size) {
763 // The query's Size is greater than the cached one. Throw out the
764 // cached data and procede with the query at the greater size.
765 CacheInfo->Pair = BBSkipFirstBlockPair();
766 CacheInfo->Size = Loc.Size;
767 CacheInfo->NonLocalDeps.clear();
768 } else if (CacheInfo->Size > Loc.Size) {
769 // This query's Size is less than the cached one. Conservatively restart
770 // the query using the greater size.
771 return getNonLocalPointerDepFromBB(Pointer,
772 Loc.getWithNewSize(CacheInfo->Size),
773 isLoad, StartBB, Result, Visited,
777 // If the query's TBAATag is inconsistent with the cached one,
778 // conservatively throw out the cached data and restart the query with
780 if (CacheInfo->TBAATag != Loc.TBAATag) {
781 if (CacheInfo->TBAATag) {
782 CacheInfo->Pair = BBSkipFirstBlockPair();
783 CacheInfo->TBAATag = 0;
784 CacheInfo->NonLocalDeps.clear();
787 return getNonLocalPointerDepFromBB(Pointer, Loc.getWithoutTBAATag(),
788 isLoad, StartBB, Result, Visited,
793 NonLocalDepInfo *Cache = &CacheInfo->NonLocalDeps;
795 // If we have valid cached information for exactly the block we are
796 // investigating, just return it with no recomputation.
797 if (CacheInfo->Pair == BBSkipFirstBlockPair(StartBB, SkipFirstBlock)) {
798 // We have a fully cached result for this query then we can just return the
799 // cached results and populate the visited set. However, we have to verify
800 // that we don't already have conflicting results for these blocks. Check
801 // to ensure that if a block in the results set is in the visited set that
802 // it was for the same pointer query.
803 if (!Visited.empty()) {
804 for (NonLocalDepInfo::iterator I = Cache->begin(), E = Cache->end();
806 DenseMap<BasicBlock*, Value*>::iterator VI = Visited.find(I->getBB());
807 if (VI == Visited.end() || VI->second == Pointer.getAddr())
810 // We have a pointer mismatch in a block. Just return clobber, saying
811 // that something was clobbered in this result. We could also do a
812 // non-fully cached query, but there is little point in doing this.
817 Value *Addr = Pointer.getAddr();
818 for (NonLocalDepInfo::iterator I = Cache->begin(), E = Cache->end();
820 Visited.insert(std::make_pair(I->getBB(), Addr));
821 if (!I->getResult().isNonLocal())
822 Result.push_back(NonLocalDepResult(I->getBB(), I->getResult(), Addr));
824 ++NumCacheCompleteNonLocalPtr;
828 // Otherwise, either this is a new block, a block with an invalid cache
829 // pointer or one that we're about to invalidate by putting more info into it
830 // than its valid cache info. If empty, the result will be valid cache info,
831 // otherwise it isn't.
833 CacheInfo->Pair = BBSkipFirstBlockPair(StartBB, SkipFirstBlock);
835 CacheInfo->Pair = BBSkipFirstBlockPair();
837 CacheInfo->TBAATag = 0;
840 SmallVector<BasicBlock*, 32> Worklist;
841 Worklist.push_back(StartBB);
843 // Keep track of the entries that we know are sorted. Previously cached
844 // entries will all be sorted. The entries we add we only sort on demand (we
845 // don't insert every element into its sorted position). We know that we
846 // won't get any reuse from currently inserted values, because we don't
847 // revisit blocks after we insert info for them.
848 unsigned NumSortedEntries = Cache->size();
849 DEBUG(AssertSorted(*Cache));
851 while (!Worklist.empty()) {
852 BasicBlock *BB = Worklist.pop_back_val();
854 // Skip the first block if we have it.
855 if (!SkipFirstBlock) {
856 // Analyze the dependency of *Pointer in FromBB. See if we already have
858 assert(Visited.count(BB) && "Should check 'visited' before adding to WL");
860 // Get the dependency info for Pointer in BB. If we have cached
861 // information, we will use it, otherwise we compute it.
862 DEBUG(AssertSorted(*Cache, NumSortedEntries));
863 MemDepResult Dep = GetNonLocalInfoForBlock(Loc, isLoad, BB, Cache,
866 // If we got a Def or Clobber, add this to the list of results.
867 if (!Dep.isNonLocal()) {
868 Result.push_back(NonLocalDepResult(BB, Dep, Pointer.getAddr()));
873 // If 'Pointer' is an instruction defined in this block, then we need to do
874 // phi translation to change it into a value live in the predecessor block.
875 // If not, we just add the predecessors to the worklist and scan them with
877 if (!Pointer.NeedsPHITranslationFromBlock(BB)) {
878 SkipFirstBlock = false;
879 for (BasicBlock **PI = PredCache->GetPreds(BB); *PI; ++PI) {
880 // Verify that we haven't looked at this block yet.
881 std::pair<DenseMap<BasicBlock*,Value*>::iterator, bool>
882 InsertRes = Visited.insert(std::make_pair(*PI, Pointer.getAddr()));
883 if (InsertRes.second) {
884 // First time we've looked at *PI.
885 Worklist.push_back(*PI);
889 // If we have seen this block before, but it was with a different
890 // pointer then we have a phi translation failure and we have to treat
891 // this as a clobber.
892 if (InsertRes.first->second != Pointer.getAddr())
893 goto PredTranslationFailure;
898 // We do need to do phi translation, if we know ahead of time we can't phi
899 // translate this value, don't even try.
900 if (!Pointer.IsPotentiallyPHITranslatable())
901 goto PredTranslationFailure;
903 // We may have added values to the cache list before this PHI translation.
904 // If so, we haven't done anything to ensure that the cache remains sorted.
905 // Sort it now (if needed) so that recursive invocations of
906 // getNonLocalPointerDepFromBB and other routines that could reuse the cache
907 // value will only see properly sorted cache arrays.
908 if (Cache && NumSortedEntries != Cache->size()) {
909 SortNonLocalDepInfoCache(*Cache, NumSortedEntries);
910 NumSortedEntries = Cache->size();
914 for (BasicBlock **PI = PredCache->GetPreds(BB); *PI; ++PI) {
915 BasicBlock *Pred = *PI;
917 // Get the PHI translated pointer in this predecessor. This can fail if
918 // not translatable, in which case the getAddr() returns null.
919 PHITransAddr PredPointer(Pointer);
920 PredPointer.PHITranslateValue(BB, Pred, 0);
922 Value *PredPtrVal = PredPointer.getAddr();
924 // Check to see if we have already visited this pred block with another
925 // pointer. If so, we can't do this lookup. This failure can occur
926 // with PHI translation when a critical edge exists and the PHI node in
927 // the successor translates to a pointer value different than the
928 // pointer the block was first analyzed with.
929 std::pair<DenseMap<BasicBlock*,Value*>::iterator, bool>
930 InsertRes = Visited.insert(std::make_pair(Pred, PredPtrVal));
932 if (!InsertRes.second) {
933 // If the predecessor was visited with PredPtr, then we already did
934 // the analysis and can ignore it.
935 if (InsertRes.first->second == PredPtrVal)
938 // Otherwise, the block was previously analyzed with a different
939 // pointer. We can't represent the result of this case, so we just
940 // treat this as a phi translation failure.
941 goto PredTranslationFailure;
944 // If PHI translation was unable to find an available pointer in this
945 // predecessor, then we have to assume that the pointer is clobbered in
946 // that predecessor. We can still do PRE of the load, which would insert
947 // a computation of the pointer in this predecessor.
948 if (PredPtrVal == 0) {
949 // Add the entry to the Result list.
950 NonLocalDepResult Entry(Pred,
951 MemDepResult::getClobber(Pred->getTerminator()),
953 Result.push_back(Entry);
955 // Since we had a phi translation failure, the cache for CacheKey won't
956 // include all of the entries that we need to immediately satisfy future
957 // queries. Mark this in NonLocalPointerDeps by setting the
958 // BBSkipFirstBlockPair pointer to null. This requires reuse of the
959 // cached value to do more work but not miss the phi trans failure.
960 NonLocalPointerInfo &NLPI = NonLocalPointerDeps[CacheKey];
961 NLPI.Pair = BBSkipFirstBlockPair();
967 // FIXME: it is entirely possible that PHI translating will end up with
968 // the same value. Consider PHI translating something like:
969 // X = phi [x, bb1], [y, bb2]. PHI translating for bb1 doesn't *need*
970 // to recurse here, pedantically speaking.
972 // If we have a problem phi translating, fall through to the code below
973 // to handle the failure condition.
974 if (getNonLocalPointerDepFromBB(PredPointer,
975 Loc.getWithNewPtr(PredPointer.getAddr()),
978 goto PredTranslationFailure;
981 // Refresh the CacheInfo/Cache pointer so that it isn't invalidated.
982 CacheInfo = &NonLocalPointerDeps[CacheKey];
983 Cache = &CacheInfo->NonLocalDeps;
984 NumSortedEntries = Cache->size();
986 // Since we did phi translation, the "Cache" set won't contain all of the
987 // results for the query. This is ok (we can still use it to accelerate
988 // specific block queries) but we can't do the fastpath "return all
989 // results from the set" Clear out the indicator for this.
990 CacheInfo->Pair = BBSkipFirstBlockPair();
992 CacheInfo->TBAATag = 0;
993 SkipFirstBlock = false;
996 PredTranslationFailure:
999 // Refresh the CacheInfo/Cache pointer if it got invalidated.
1000 CacheInfo = &NonLocalPointerDeps[CacheKey];
1001 Cache = &CacheInfo->NonLocalDeps;
1002 NumSortedEntries = Cache->size();
1005 // Since we failed phi translation, the "Cache" set won't contain all of the
1006 // results for the query. This is ok (we can still use it to accelerate
1007 // specific block queries) but we can't do the fastpath "return all
1008 // results from the set". Clear out the indicator for this.
1009 CacheInfo->Pair = BBSkipFirstBlockPair();
1010 CacheInfo->Size = 0;
1011 CacheInfo->TBAATag = 0;
1013 // If *nothing* works, mark the pointer as being clobbered by the first
1014 // instruction in this block.
1016 // If this is the magic first block, return this as a clobber of the whole
1017 // incoming value. Since we can't phi translate to one of the predecessors,
1018 // we have to bail out.
1022 for (NonLocalDepInfo::reverse_iterator I = Cache->rbegin(); ; ++I) {
1023 assert(I != Cache->rend() && "Didn't find current block??");
1024 if (I->getBB() != BB)
1027 assert(I->getResult().isNonLocal() &&
1028 "Should only be here with transparent block");
1029 I->setResult(MemDepResult::getClobber(BB->begin()));
1030 ReverseNonLocalPtrDeps[BB->begin()].insert(CacheKey);
1031 Result.push_back(NonLocalDepResult(I->getBB(), I->getResult(),
1032 Pointer.getAddr()));
1037 // Okay, we're done now. If we added new values to the cache, re-sort it.
1038 SortNonLocalDepInfoCache(*Cache, NumSortedEntries);
1039 DEBUG(AssertSorted(*Cache));
1043 /// RemoveCachedNonLocalPointerDependencies - If P exists in
1044 /// CachedNonLocalPointerInfo, remove it.
1045 void MemoryDependenceAnalysis::
1046 RemoveCachedNonLocalPointerDependencies(ValueIsLoadPair P) {
1047 CachedNonLocalPointerInfo::iterator It =
1048 NonLocalPointerDeps.find(P);
1049 if (It == NonLocalPointerDeps.end()) return;
1051 // Remove all of the entries in the BB->val map. This involves removing
1052 // instructions from the reverse map.
1053 NonLocalDepInfo &PInfo = It->second.NonLocalDeps;
1055 for (unsigned i = 0, e = PInfo.size(); i != e; ++i) {
1056 Instruction *Target = PInfo[i].getResult().getInst();
1057 if (Target == 0) continue; // Ignore non-local dep results.
1058 assert(Target->getParent() == PInfo[i].getBB());
1060 // Eliminating the dirty entry from 'Cache', so update the reverse info.
1061 RemoveFromReverseMap(ReverseNonLocalPtrDeps, Target, P);
1064 // Remove P from NonLocalPointerDeps (which deletes NonLocalDepInfo).
1065 NonLocalPointerDeps.erase(It);
1069 /// invalidateCachedPointerInfo - This method is used to invalidate cached
1070 /// information about the specified pointer, because it may be too
1071 /// conservative in memdep. This is an optional call that can be used when
1072 /// the client detects an equivalence between the pointer and some other
1073 /// value and replaces the other value with ptr. This can make Ptr available
1074 /// in more places that cached info does not necessarily keep.
1075 void MemoryDependenceAnalysis::invalidateCachedPointerInfo(Value *Ptr) {
1076 // If Ptr isn't really a pointer, just ignore it.
1077 if (!Ptr->getType()->isPointerTy()) return;
1078 // Flush store info for the pointer.
1079 RemoveCachedNonLocalPointerDependencies(ValueIsLoadPair(Ptr, false));
1080 // Flush load info for the pointer.
1081 RemoveCachedNonLocalPointerDependencies(ValueIsLoadPair(Ptr, true));
1084 /// invalidateCachedPredecessors - Clear the PredIteratorCache info.
1085 /// This needs to be done when the CFG changes, e.g., due to splitting
1087 void MemoryDependenceAnalysis::invalidateCachedPredecessors() {
1091 /// removeInstruction - Remove an instruction from the dependence analysis,
1092 /// updating the dependence of instructions that previously depended on it.
1093 /// This method attempts to keep the cache coherent using the reverse map.
1094 void MemoryDependenceAnalysis::removeInstruction(Instruction *RemInst) {
1095 // Walk through the Non-local dependencies, removing this one as the value
1096 // for any cached queries.
1097 NonLocalDepMapType::iterator NLDI = NonLocalDeps.find(RemInst);
1098 if (NLDI != NonLocalDeps.end()) {
1099 NonLocalDepInfo &BlockMap = NLDI->second.first;
1100 for (NonLocalDepInfo::iterator DI = BlockMap.begin(), DE = BlockMap.end();
1102 if (Instruction *Inst = DI->getResult().getInst())
1103 RemoveFromReverseMap(ReverseNonLocalDeps, Inst, RemInst);
1104 NonLocalDeps.erase(NLDI);
1107 // If we have a cached local dependence query for this instruction, remove it.
1109 LocalDepMapType::iterator LocalDepEntry = LocalDeps.find(RemInst);
1110 if (LocalDepEntry != LocalDeps.end()) {
1111 // Remove us from DepInst's reverse set now that the local dep info is gone.
1112 if (Instruction *Inst = LocalDepEntry->second.getInst())
1113 RemoveFromReverseMap(ReverseLocalDeps, Inst, RemInst);
1115 // Remove this local dependency info.
1116 LocalDeps.erase(LocalDepEntry);
1119 // If we have any cached pointer dependencies on this instruction, remove
1120 // them. If the instruction has non-pointer type, then it can't be a pointer
1123 // Remove it from both the load info and the store info. The instruction
1124 // can't be in either of these maps if it is non-pointer.
1125 if (RemInst->getType()->isPointerTy()) {
1126 RemoveCachedNonLocalPointerDependencies(ValueIsLoadPair(RemInst, false));
1127 RemoveCachedNonLocalPointerDependencies(ValueIsLoadPair(RemInst, true));
1130 // Loop over all of the things that depend on the instruction we're removing.
1132 SmallVector<std::pair<Instruction*, Instruction*>, 8> ReverseDepsToAdd;
1134 // If we find RemInst as a clobber or Def in any of the maps for other values,
1135 // we need to replace its entry with a dirty version of the instruction after
1136 // it. If RemInst is a terminator, we use a null dirty value.
1138 // Using a dirty version of the instruction after RemInst saves having to scan
1139 // the entire block to get to this point.
1140 MemDepResult NewDirtyVal;
1141 if (!RemInst->isTerminator())
1142 NewDirtyVal = MemDepResult::getDirty(++BasicBlock::iterator(RemInst));
1144 ReverseDepMapType::iterator ReverseDepIt = ReverseLocalDeps.find(RemInst);
1145 if (ReverseDepIt != ReverseLocalDeps.end()) {
1146 SmallPtrSet<Instruction*, 4> &ReverseDeps = ReverseDepIt->second;
1147 // RemInst can't be the terminator if it has local stuff depending on it.
1148 assert(!ReverseDeps.empty() && !isa<TerminatorInst>(RemInst) &&
1149 "Nothing can locally depend on a terminator");
1151 for (SmallPtrSet<Instruction*, 4>::iterator I = ReverseDeps.begin(),
1152 E = ReverseDeps.end(); I != E; ++I) {
1153 Instruction *InstDependingOnRemInst = *I;
1154 assert(InstDependingOnRemInst != RemInst &&
1155 "Already removed our local dep info");
1157 LocalDeps[InstDependingOnRemInst] = NewDirtyVal;
1159 // Make sure to remember that new things depend on NewDepInst.
1160 assert(NewDirtyVal.getInst() && "There is no way something else can have "
1161 "a local dep on this if it is a terminator!");
1162 ReverseDepsToAdd.push_back(std::make_pair(NewDirtyVal.getInst(),
1163 InstDependingOnRemInst));
1166 ReverseLocalDeps.erase(ReverseDepIt);
1168 // Add new reverse deps after scanning the set, to avoid invalidating the
1169 // 'ReverseDeps' reference.
1170 while (!ReverseDepsToAdd.empty()) {
1171 ReverseLocalDeps[ReverseDepsToAdd.back().first]
1172 .insert(ReverseDepsToAdd.back().second);
1173 ReverseDepsToAdd.pop_back();
1177 ReverseDepIt = ReverseNonLocalDeps.find(RemInst);
1178 if (ReverseDepIt != ReverseNonLocalDeps.end()) {
1179 SmallPtrSet<Instruction*, 4> &Set = ReverseDepIt->second;
1180 for (SmallPtrSet<Instruction*, 4>::iterator I = Set.begin(), E = Set.end();
1182 assert(*I != RemInst && "Already removed NonLocalDep info for RemInst");
1184 PerInstNLInfo &INLD = NonLocalDeps[*I];
1185 // The information is now dirty!
1188 for (NonLocalDepInfo::iterator DI = INLD.first.begin(),
1189 DE = INLD.first.end(); DI != DE; ++DI) {
1190 if (DI->getResult().getInst() != RemInst) continue;
1192 // Convert to a dirty entry for the subsequent instruction.
1193 DI->setResult(NewDirtyVal);
1195 if (Instruction *NextI = NewDirtyVal.getInst())
1196 ReverseDepsToAdd.push_back(std::make_pair(NextI, *I));
1200 ReverseNonLocalDeps.erase(ReverseDepIt);
1202 // Add new reverse deps after scanning the set, to avoid invalidating 'Set'
1203 while (!ReverseDepsToAdd.empty()) {
1204 ReverseNonLocalDeps[ReverseDepsToAdd.back().first]
1205 .insert(ReverseDepsToAdd.back().second);
1206 ReverseDepsToAdd.pop_back();
1210 // If the instruction is in ReverseNonLocalPtrDeps then it appears as a
1211 // value in the NonLocalPointerDeps info.
1212 ReverseNonLocalPtrDepTy::iterator ReversePtrDepIt =
1213 ReverseNonLocalPtrDeps.find(RemInst);
1214 if (ReversePtrDepIt != ReverseNonLocalPtrDeps.end()) {
1215 SmallPtrSet<ValueIsLoadPair, 4> &Set = ReversePtrDepIt->second;
1216 SmallVector<std::pair<Instruction*, ValueIsLoadPair>,8> ReversePtrDepsToAdd;
1218 for (SmallPtrSet<ValueIsLoadPair, 4>::iterator I = Set.begin(),
1219 E = Set.end(); I != E; ++I) {
1220 ValueIsLoadPair P = *I;
1221 assert(P.getPointer() != RemInst &&
1222 "Already removed NonLocalPointerDeps info for RemInst");
1224 NonLocalDepInfo &NLPDI = NonLocalPointerDeps[P].NonLocalDeps;
1226 // The cache is not valid for any specific block anymore.
1227 NonLocalPointerDeps[P].Pair = BBSkipFirstBlockPair();
1228 NonLocalPointerDeps[P].Size = 0;
1229 NonLocalPointerDeps[P].TBAATag = 0;
1231 // Update any entries for RemInst to use the instruction after it.
1232 for (NonLocalDepInfo::iterator DI = NLPDI.begin(), DE = NLPDI.end();
1234 if (DI->getResult().getInst() != RemInst) continue;
1236 // Convert to a dirty entry for the subsequent instruction.
1237 DI->setResult(NewDirtyVal);
1239 if (Instruction *NewDirtyInst = NewDirtyVal.getInst())
1240 ReversePtrDepsToAdd.push_back(std::make_pair(NewDirtyInst, P));
1243 // Re-sort the NonLocalDepInfo. Changing the dirty entry to its
1244 // subsequent value may invalidate the sortedness.
1245 std::sort(NLPDI.begin(), NLPDI.end());
1248 ReverseNonLocalPtrDeps.erase(ReversePtrDepIt);
1250 while (!ReversePtrDepsToAdd.empty()) {
1251 ReverseNonLocalPtrDeps[ReversePtrDepsToAdd.back().first]
1252 .insert(ReversePtrDepsToAdd.back().second);
1253 ReversePtrDepsToAdd.pop_back();
1258 assert(!NonLocalDeps.count(RemInst) && "RemInst got reinserted?");
1259 AA->deleteValue(RemInst);
1260 DEBUG(verifyRemoved(RemInst));
1262 /// verifyRemoved - Verify that the specified instruction does not occur
1263 /// in our internal data structures.
1264 void MemoryDependenceAnalysis::verifyRemoved(Instruction *D) const {
1265 for (LocalDepMapType::const_iterator I = LocalDeps.begin(),
1266 E = LocalDeps.end(); I != E; ++I) {
1267 assert(I->first != D && "Inst occurs in data structures");
1268 assert(I->second.getInst() != D &&
1269 "Inst occurs in data structures");
1272 for (CachedNonLocalPointerInfo::const_iterator I =NonLocalPointerDeps.begin(),
1273 E = NonLocalPointerDeps.end(); I != E; ++I) {
1274 assert(I->first.getPointer() != D && "Inst occurs in NLPD map key");
1275 const NonLocalDepInfo &Val = I->second.NonLocalDeps;
1276 for (NonLocalDepInfo::const_iterator II = Val.begin(), E = Val.end();
1278 assert(II->getResult().getInst() != D && "Inst occurs as NLPD value");
1281 for (NonLocalDepMapType::const_iterator I = NonLocalDeps.begin(),
1282 E = NonLocalDeps.end(); I != E; ++I) {
1283 assert(I->first != D && "Inst occurs in data structures");
1284 const PerInstNLInfo &INLD = I->second;
1285 for (NonLocalDepInfo::const_iterator II = INLD.first.begin(),
1286 EE = INLD.first.end(); II != EE; ++II)
1287 assert(II->getResult().getInst() != D && "Inst occurs in data structures");
1290 for (ReverseDepMapType::const_iterator I = ReverseLocalDeps.begin(),
1291 E = ReverseLocalDeps.end(); I != E; ++I) {
1292 assert(I->first != D && "Inst occurs in data structures");
1293 for (SmallPtrSet<Instruction*, 4>::const_iterator II = I->second.begin(),
1294 EE = I->second.end(); II != EE; ++II)
1295 assert(*II != D && "Inst occurs in data structures");
1298 for (ReverseDepMapType::const_iterator I = ReverseNonLocalDeps.begin(),
1299 E = ReverseNonLocalDeps.end();
1301 assert(I->first != D && "Inst occurs in data structures");
1302 for (SmallPtrSet<Instruction*, 4>::const_iterator II = I->second.begin(),
1303 EE = I->second.end(); II != EE; ++II)
1304 assert(*II != D && "Inst occurs in data structures");
1307 for (ReverseNonLocalPtrDepTy::const_iterator
1308 I = ReverseNonLocalPtrDeps.begin(),
1309 E = ReverseNonLocalPtrDeps.end(); I != E; ++I) {
1310 assert(I->first != D && "Inst occurs in rev NLPD map");
1312 for (SmallPtrSet<ValueIsLoadPair, 4>::const_iterator II = I->second.begin(),
1313 E = I->second.end(); II != E; ++II)
1314 assert(*II != ValueIsLoadPair(D, false) &&
1315 *II != ValueIsLoadPair(D, true) &&
1316 "Inst occurs in ReverseNonLocalPtrDeps map");