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/Analysis/AliasAnalysis.h"
23 #include "llvm/Analysis/InstructionSimplify.h"
24 #include "llvm/Analysis/MemoryBuiltins.h"
25 #include "llvm/ADT/Statistic.h"
26 #include "llvm/ADT/STLExtras.h"
27 #include "llvm/Support/PredIteratorCache.h"
28 #include "llvm/Support/Debug.h"
31 STATISTIC(NumCacheNonLocal, "Number of fully cached non-local responses");
32 STATISTIC(NumCacheDirtyNonLocal, "Number of dirty cached non-local responses");
33 STATISTIC(NumUncacheNonLocal, "Number of uncached non-local responses");
35 STATISTIC(NumCacheNonLocalPtr,
36 "Number of fully cached non-local ptr responses");
37 STATISTIC(NumCacheDirtyNonLocalPtr,
38 "Number of cached, but dirty, non-local ptr responses");
39 STATISTIC(NumUncacheNonLocalPtr,
40 "Number of uncached non-local ptr responses");
41 STATISTIC(NumCacheCompleteNonLocalPtr,
42 "Number of block queries that were completely cached");
44 char MemoryDependenceAnalysis::ID = 0;
46 // Register this pass...
47 static RegisterPass<MemoryDependenceAnalysis> X("memdep",
48 "Memory Dependence Analysis", false, true);
50 MemoryDependenceAnalysis::MemoryDependenceAnalysis()
51 : FunctionPass(&ID), PredCache(0) {
53 MemoryDependenceAnalysis::~MemoryDependenceAnalysis() {
56 /// Clean up memory in between runs
57 void MemoryDependenceAnalysis::releaseMemory() {
60 NonLocalPointerDeps.clear();
61 ReverseLocalDeps.clear();
62 ReverseNonLocalDeps.clear();
63 ReverseNonLocalPtrDeps.clear();
69 /// getAnalysisUsage - Does not modify anything. It uses Alias Analysis.
71 void MemoryDependenceAnalysis::getAnalysisUsage(AnalysisUsage &AU) const {
73 AU.addRequiredTransitive<AliasAnalysis>();
76 bool MemoryDependenceAnalysis::runOnFunction(Function &) {
77 AA = &getAnalysis<AliasAnalysis>();
79 PredCache.reset(new PredIteratorCache());
83 /// RemoveFromReverseMap - This is a helper function that removes Val from
84 /// 'Inst's set in ReverseMap. If the set becomes empty, remove Inst's entry.
85 template <typename KeyTy>
86 static void RemoveFromReverseMap(DenseMap<Instruction*,
87 SmallPtrSet<KeyTy, 4> > &ReverseMap,
88 Instruction *Inst, KeyTy Val) {
89 typename DenseMap<Instruction*, SmallPtrSet<KeyTy, 4> >::iterator
90 InstIt = ReverseMap.find(Inst);
91 assert(InstIt != ReverseMap.end() && "Reverse map out of sync?");
92 bool Found = InstIt->second.erase(Val);
93 assert(Found && "Invalid reverse map!"); Found=Found;
94 if (InstIt->second.empty())
95 ReverseMap.erase(InstIt);
99 /// getCallSiteDependencyFrom - Private helper for finding the local
100 /// dependencies of a call site.
101 MemDepResult MemoryDependenceAnalysis::
102 getCallSiteDependencyFrom(CallSite CS, bool isReadOnlyCall,
103 BasicBlock::iterator ScanIt, BasicBlock *BB) {
104 // Walk backwards through the block, looking for dependencies
105 while (ScanIt != BB->begin()) {
106 Instruction *Inst = --ScanIt;
108 // If this inst is a memory op, get the pointer it accessed
110 uint64_t PointerSize = 0;
111 if (StoreInst *S = dyn_cast<StoreInst>(Inst)) {
112 Pointer = S->getPointerOperand();
113 PointerSize = AA->getTypeStoreSize(S->getOperand(0)->getType());
114 } else if (VAArgInst *V = dyn_cast<VAArgInst>(Inst)) {
115 Pointer = V->getOperand(0);
116 PointerSize = AA->getTypeStoreSize(V->getType());
117 } else if (isFreeCall(Inst)) {
118 Pointer = Inst->getOperand(1);
119 // calls to free() erase the entire structure
121 } else if (isa<CallInst>(Inst) || isa<InvokeInst>(Inst)) {
122 // Debug intrinsics don't cause dependences.
123 if (isa<DbgInfoIntrinsic>(Inst)) continue;
124 CallSite InstCS = CallSite::get(Inst);
125 // If these two calls do not interfere, look past it.
126 switch (AA->getModRefInfo(CS, InstCS)) {
127 case AliasAnalysis::NoModRef:
128 // If the two calls don't interact (e.g. InstCS is readnone) keep
131 case AliasAnalysis::Ref:
132 // If the two calls read the same memory locations and CS is a readonly
133 // function, then we have two cases: 1) the calls may not interfere with
134 // each other at all. 2) the calls may produce the same value. In case
135 // #1 we want to ignore the values, in case #2, we want to return Inst
136 // as a Def dependence. This allows us to CSE in cases like:
139 // Y = strlen(P); // Y = X
140 if (isReadOnlyCall) {
141 if (CS.getCalledFunction() != 0 &&
142 CS.getCalledFunction() == InstCS.getCalledFunction())
143 return MemDepResult::getDef(Inst);
144 // Ignore unrelated read/read call dependences.
149 return MemDepResult::getClobber(Inst);
152 // Non-memory instruction.
156 if (AA->getModRefInfo(CS, Pointer, PointerSize) != AliasAnalysis::NoModRef)
157 return MemDepResult::getClobber(Inst);
160 // No dependence found. If this is the entry block of the function, it is a
161 // clobber, otherwise it is non-local.
162 if (BB != &BB->getParent()->getEntryBlock())
163 return MemDepResult::getNonLocal();
164 return MemDepResult::getClobber(ScanIt);
167 /// getPointerDependencyFrom - Return the instruction on which a memory
168 /// location depends. If isLoad is true, this routine ignore may-aliases with
169 /// read-only operations.
170 MemDepResult MemoryDependenceAnalysis::
171 getPointerDependencyFrom(Value *MemPtr, uint64_t MemSize, bool isLoad,
172 BasicBlock::iterator ScanIt, BasicBlock *BB) {
174 Value *invariantTag = 0;
176 // Walk backwards through the basic block, looking for dependencies.
177 while (ScanIt != BB->begin()) {
178 Instruction *Inst = --ScanIt;
180 // If we're in an invariant region, no dependencies can be found before
181 // we pass an invariant-begin marker.
182 if (invariantTag == Inst) {
185 } else if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(Inst)) {
186 // If we pass an invariant-end marker, then we've just entered an
187 // invariant region and can start ignoring dependencies.
188 if (II->getIntrinsicID() == Intrinsic::invariant_end) {
189 uint64_t invariantSize = ~0ULL;
190 if (ConstantInt *CI = dyn_cast<ConstantInt>(II->getOperand(2)))
191 invariantSize = CI->getZExtValue();
193 AliasAnalysis::AliasResult R =
194 AA->alias(II->getOperand(3), invariantSize, MemPtr, MemSize);
195 if (R == AliasAnalysis::MustAlias) {
196 invariantTag = II->getOperand(1);
200 // If we reach a lifetime begin or end marker, then the query ends here
201 // because the value is undefined.
202 } else if (II->getIntrinsicID() == Intrinsic::lifetime_start ||
203 II->getIntrinsicID() == Intrinsic::lifetime_end) {
204 uint64_t invariantSize = ~0ULL;
205 if (ConstantInt *CI = dyn_cast<ConstantInt>(II->getOperand(1)))
206 invariantSize = CI->getZExtValue();
208 AliasAnalysis::AliasResult R =
209 AA->alias(II->getOperand(2), invariantSize, MemPtr, MemSize);
210 if (R == AliasAnalysis::MustAlias)
211 return MemDepResult::getDef(II);
215 // If we're querying on a load and we're in an invariant region, we're done
216 // at this point. Nothing a load depends on can live in an invariant region.
217 if (isLoad && invariantTag) continue;
219 // Debug intrinsics don't cause dependences.
220 if (isa<DbgInfoIntrinsic>(Inst)) continue;
222 // Values depend on loads if the pointers are must aliased. This means that
223 // a load depends on another must aliased load from the same value.
224 if (LoadInst *LI = dyn_cast<LoadInst>(Inst)) {
225 Value *Pointer = LI->getPointerOperand();
226 uint64_t PointerSize = AA->getTypeStoreSize(LI->getType());
228 // If we found a pointer, check if it could be the same as our pointer.
229 AliasAnalysis::AliasResult R =
230 AA->alias(Pointer, PointerSize, MemPtr, MemSize);
231 if (R == AliasAnalysis::NoAlias)
234 // May-alias loads don't depend on each other without a dependence.
235 if (isLoad && R == AliasAnalysis::MayAlias)
237 // Stores depend on may and must aliased loads, loads depend on must-alias
239 return MemDepResult::getDef(Inst);
242 if (StoreInst *SI = dyn_cast<StoreInst>(Inst)) {
243 // There can't be stores to the value we care about inside an
245 if (invariantTag) continue;
247 // If alias analysis can tell that this store is guaranteed to not modify
248 // the query pointer, ignore it. Use getModRefInfo to handle cases where
249 // the query pointer points to constant memory etc.
250 if (AA->getModRefInfo(SI, MemPtr, MemSize) == AliasAnalysis::NoModRef)
253 // Ok, this store might clobber the query pointer. Check to see if it is
254 // a must alias: in this case, we want to return this as a def.
255 Value *Pointer = SI->getPointerOperand();
256 uint64_t PointerSize = AA->getTypeStoreSize(SI->getOperand(0)->getType());
258 // If we found a pointer, check if it could be the same as our pointer.
259 AliasAnalysis::AliasResult R =
260 AA->alias(Pointer, PointerSize, MemPtr, MemSize);
262 if (R == AliasAnalysis::NoAlias)
264 if (R == AliasAnalysis::MayAlias)
265 return MemDepResult::getClobber(Inst);
266 return MemDepResult::getDef(Inst);
269 // If this is an allocation, and if we know that the accessed pointer is to
270 // the allocation, return Def. This means that there is no dependence and
271 // the access can be optimized based on that. For example, a load could
273 // Note: Only determine this to be a malloc if Inst is the malloc call, not
274 // a subsequent bitcast of the malloc call result. There can be stores to
275 // the malloced memory between the malloc call and its bitcast uses, and we
276 // need to continue scanning until the malloc call.
277 if (isa<AllocaInst>(Inst) || extractMallocCall(Inst)) {
278 Value *AccessPtr = MemPtr->getUnderlyingObject();
280 if (AccessPtr == Inst ||
281 AA->alias(Inst, 1, AccessPtr, 1) == AliasAnalysis::MustAlias)
282 return MemDepResult::getDef(Inst);
286 // See if this instruction (e.g. a call or vaarg) mod/ref's the pointer.
287 switch (AA->getModRefInfo(Inst, MemPtr, MemSize)) {
288 case AliasAnalysis::NoModRef:
289 // If the call has no effect on the queried pointer, just ignore it.
291 case AliasAnalysis::Mod:
292 // If we're in an invariant region, we can ignore calls that ONLY
293 // modify the pointer.
294 if (invariantTag) continue;
295 return MemDepResult::getClobber(Inst);
296 case AliasAnalysis::Ref:
297 // If the call is known to never store to the pointer, and if this is a
298 // load query, we can safely ignore it (scan past it).
302 // Otherwise, there is a potential dependence. Return a clobber.
303 return MemDepResult::getClobber(Inst);
307 // No dependence found. If this is the entry block of the function, it is a
308 // clobber, otherwise it is non-local.
309 if (BB != &BB->getParent()->getEntryBlock())
310 return MemDepResult::getNonLocal();
311 return MemDepResult::getClobber(ScanIt);
314 /// getDependency - Return the instruction on which a memory operation
316 MemDepResult MemoryDependenceAnalysis::getDependency(Instruction *QueryInst) {
317 Instruction *ScanPos = QueryInst;
319 // Check for a cached result
320 MemDepResult &LocalCache = LocalDeps[QueryInst];
322 // If the cached entry is non-dirty, just return it. Note that this depends
323 // on MemDepResult's default constructing to 'dirty'.
324 if (!LocalCache.isDirty())
327 // Otherwise, if we have a dirty entry, we know we can start the scan at that
328 // instruction, which may save us some work.
329 if (Instruction *Inst = LocalCache.getInst()) {
332 RemoveFromReverseMap(ReverseLocalDeps, Inst, QueryInst);
335 BasicBlock *QueryParent = QueryInst->getParent();
338 uint64_t MemSize = 0;
341 if (BasicBlock::iterator(QueryInst) == QueryParent->begin()) {
342 // No dependence found. If this is the entry block of the function, it is a
343 // clobber, otherwise it is non-local.
344 if (QueryParent != &QueryParent->getParent()->getEntryBlock())
345 LocalCache = MemDepResult::getNonLocal();
347 LocalCache = MemDepResult::getClobber(QueryInst);
348 } else if (StoreInst *SI = dyn_cast<StoreInst>(QueryInst)) {
349 // If this is a volatile store, don't mess around with it. Just return the
350 // previous instruction as a clobber.
351 if (SI->isVolatile())
352 LocalCache = MemDepResult::getClobber(--BasicBlock::iterator(ScanPos));
354 MemPtr = SI->getPointerOperand();
355 MemSize = AA->getTypeStoreSize(SI->getOperand(0)->getType());
357 } else if (LoadInst *LI = dyn_cast<LoadInst>(QueryInst)) {
358 // If this is a volatile load, don't mess around with it. Just return the
359 // previous instruction as a clobber.
360 if (LI->isVolatile())
361 LocalCache = MemDepResult::getClobber(--BasicBlock::iterator(ScanPos));
363 MemPtr = LI->getPointerOperand();
364 MemSize = AA->getTypeStoreSize(LI->getType());
366 } else if (isFreeCall(QueryInst)) {
367 MemPtr = QueryInst->getOperand(1);
368 // calls to free() erase the entire structure, not just a field.
370 } else if (isa<CallInst>(QueryInst) || isa<InvokeInst>(QueryInst)) {
371 CallSite QueryCS = CallSite::get(QueryInst);
372 bool isReadOnly = AA->onlyReadsMemory(QueryCS);
373 LocalCache = getCallSiteDependencyFrom(QueryCS, isReadOnly, ScanPos,
376 // Non-memory instruction.
377 LocalCache = MemDepResult::getClobber(--BasicBlock::iterator(ScanPos));
380 // If we need to do a pointer scan, make it happen.
382 LocalCache = getPointerDependencyFrom(MemPtr, MemSize,
383 isa<LoadInst>(QueryInst),
384 ScanPos, QueryParent);
386 // Remember the result!
387 if (Instruction *I = LocalCache.getInst())
388 ReverseLocalDeps[I].insert(QueryInst);
394 /// AssertSorted - This method is used when -debug is specified to verify that
395 /// cache arrays are properly kept sorted.
396 static void AssertSorted(MemoryDependenceAnalysis::NonLocalDepInfo &Cache,
398 if (Count == -1) Count = Cache.size();
399 if (Count == 0) return;
401 for (unsigned i = 1; i != unsigned(Count); ++i)
402 assert(Cache[i-1] <= Cache[i] && "Cache isn't sorted!");
406 /// getNonLocalCallDependency - Perform a full dependency query for the
407 /// specified call, returning the set of blocks that the value is
408 /// potentially live across. The returned set of results will include a
409 /// "NonLocal" result for all blocks where the value is live across.
411 /// This method assumes the instruction returns a "NonLocal" dependency
412 /// within its own block.
414 /// This returns a reference to an internal data structure that may be
415 /// invalidated on the next non-local query or when an instruction is
416 /// removed. Clients must copy this data if they want it around longer than
418 const MemoryDependenceAnalysis::NonLocalDepInfo &
419 MemoryDependenceAnalysis::getNonLocalCallDependency(CallSite QueryCS) {
420 assert(getDependency(QueryCS.getInstruction()).isNonLocal() &&
421 "getNonLocalCallDependency should only be used on calls with non-local deps!");
422 PerInstNLInfo &CacheP = NonLocalDeps[QueryCS.getInstruction()];
423 NonLocalDepInfo &Cache = CacheP.first;
425 /// DirtyBlocks - This is the set of blocks that need to be recomputed. In
426 /// the cached case, this can happen due to instructions being deleted etc. In
427 /// the uncached case, this starts out as the set of predecessors we care
429 SmallVector<BasicBlock*, 32> DirtyBlocks;
431 if (!Cache.empty()) {
432 // Okay, we have a cache entry. If we know it is not dirty, just return it
433 // with no computation.
434 if (!CacheP.second) {
439 // If we already have a partially computed set of results, scan them to
440 // determine what is dirty, seeding our initial DirtyBlocks worklist.
441 for (NonLocalDepInfo::iterator I = Cache.begin(), E = Cache.end();
443 if (I->second.isDirty())
444 DirtyBlocks.push_back(I->first);
446 // Sort the cache so that we can do fast binary search lookups below.
447 std::sort(Cache.begin(), Cache.end());
449 ++NumCacheDirtyNonLocal;
450 //cerr << "CACHED CASE: " << DirtyBlocks.size() << " dirty: "
451 // << Cache.size() << " cached: " << *QueryInst;
453 // Seed DirtyBlocks with each of the preds of QueryInst's block.
454 BasicBlock *QueryBB = QueryCS.getInstruction()->getParent();
455 for (BasicBlock **PI = PredCache->GetPreds(QueryBB); *PI; ++PI)
456 DirtyBlocks.push_back(*PI);
457 NumUncacheNonLocal++;
460 // isReadonlyCall - If this is a read-only call, we can be more aggressive.
461 bool isReadonlyCall = AA->onlyReadsMemory(QueryCS);
463 SmallPtrSet<BasicBlock*, 64> Visited;
465 unsigned NumSortedEntries = Cache.size();
466 DEBUG(AssertSorted(Cache));
468 // Iterate while we still have blocks to update.
469 while (!DirtyBlocks.empty()) {
470 BasicBlock *DirtyBB = DirtyBlocks.back();
471 DirtyBlocks.pop_back();
473 // Already processed this block?
474 if (!Visited.insert(DirtyBB))
477 // Do a binary search to see if we already have an entry for this block in
478 // the cache set. If so, find it.
479 DEBUG(AssertSorted(Cache, NumSortedEntries));
480 NonLocalDepInfo::iterator Entry =
481 std::upper_bound(Cache.begin(), Cache.begin()+NumSortedEntries,
482 std::make_pair(DirtyBB, MemDepResult()));
483 if (Entry != Cache.begin() && prior(Entry)->first == DirtyBB)
486 MemDepResult *ExistingResult = 0;
487 if (Entry != Cache.begin()+NumSortedEntries &&
488 Entry->first == DirtyBB) {
489 // If we already have an entry, and if it isn't already dirty, the block
491 if (!Entry->second.isDirty())
494 // Otherwise, remember this slot so we can update the value.
495 ExistingResult = &Entry->second;
498 // If the dirty entry has a pointer, start scanning from it so we don't have
499 // to rescan the entire block.
500 BasicBlock::iterator ScanPos = DirtyBB->end();
501 if (ExistingResult) {
502 if (Instruction *Inst = ExistingResult->getInst()) {
504 // We're removing QueryInst's use of Inst.
505 RemoveFromReverseMap(ReverseNonLocalDeps, Inst,
506 QueryCS.getInstruction());
510 // Find out if this block has a local dependency for QueryInst.
513 if (ScanPos != DirtyBB->begin()) {
514 Dep = getCallSiteDependencyFrom(QueryCS, isReadonlyCall,ScanPos, DirtyBB);
515 } else if (DirtyBB != &DirtyBB->getParent()->getEntryBlock()) {
516 // No dependence found. If this is the entry block of the function, it is
517 // a clobber, otherwise it is non-local.
518 Dep = MemDepResult::getNonLocal();
520 Dep = MemDepResult::getClobber(ScanPos);
523 // If we had a dirty entry for the block, update it. Otherwise, just add
526 *ExistingResult = Dep;
528 Cache.push_back(std::make_pair(DirtyBB, Dep));
530 // If the block has a dependency (i.e. it isn't completely transparent to
531 // the value), remember the association!
532 if (!Dep.isNonLocal()) {
533 // Keep the ReverseNonLocalDeps map up to date so we can efficiently
534 // update this when we remove instructions.
535 if (Instruction *Inst = Dep.getInst())
536 ReverseNonLocalDeps[Inst].insert(QueryCS.getInstruction());
539 // If the block *is* completely transparent to the load, we need to check
540 // the predecessors of this block. Add them to our worklist.
541 for (BasicBlock **PI = PredCache->GetPreds(DirtyBB); *PI; ++PI)
542 DirtyBlocks.push_back(*PI);
549 /// getNonLocalPointerDependency - Perform a full dependency query for an
550 /// access to the specified (non-volatile) memory location, returning the
551 /// set of instructions that either define or clobber the value.
553 /// This method assumes the pointer has a "NonLocal" dependency within its
556 void MemoryDependenceAnalysis::
557 getNonLocalPointerDependency(Value *Pointer, bool isLoad, BasicBlock *FromBB,
558 SmallVectorImpl<NonLocalDepEntry> &Result) {
559 assert(isa<PointerType>(Pointer->getType()) &&
560 "Can't get pointer deps of a non-pointer!");
563 // We know that the pointer value is live into FromBB find the def/clobbers
564 // from presecessors.
565 const Type *EltTy = cast<PointerType>(Pointer->getType())->getElementType();
566 uint64_t PointeeSize = AA->getTypeStoreSize(EltTy);
568 // This is the set of blocks we've inspected, and the pointer we consider in
569 // each block. Because of critical edges, we currently bail out if querying
570 // a block with multiple different pointers. This can happen during PHI
572 DenseMap<BasicBlock*, Value*> Visited;
573 if (!getNonLocalPointerDepFromBB(Pointer, PointeeSize, isLoad, FromBB,
574 Result, Visited, true))
577 Result.push_back(std::make_pair(FromBB,
578 MemDepResult::getClobber(FromBB->begin())));
581 /// GetNonLocalInfoForBlock - Compute the memdep value for BB with
582 /// Pointer/PointeeSize using either cached information in Cache or by doing a
583 /// lookup (which may use dirty cache info if available). If we do a lookup,
584 /// add the result to the cache.
585 MemDepResult MemoryDependenceAnalysis::
586 GetNonLocalInfoForBlock(Value *Pointer, uint64_t PointeeSize,
587 bool isLoad, BasicBlock *BB,
588 NonLocalDepInfo *Cache, unsigned NumSortedEntries) {
590 // Do a binary search to see if we already have an entry for this block in
591 // the cache set. If so, find it.
592 NonLocalDepInfo::iterator Entry =
593 std::upper_bound(Cache->begin(), Cache->begin()+NumSortedEntries,
594 std::make_pair(BB, MemDepResult()));
595 if (Entry != Cache->begin() && prior(Entry)->first == BB)
598 MemDepResult *ExistingResult = 0;
599 if (Entry != Cache->begin()+NumSortedEntries && Entry->first == BB)
600 ExistingResult = &Entry->second;
602 // If we have a cached entry, and it is non-dirty, use it as the value for
604 if (ExistingResult && !ExistingResult->isDirty()) {
605 ++NumCacheNonLocalPtr;
606 return *ExistingResult;
609 // Otherwise, we have to scan for the value. If we have a dirty cache
610 // entry, start scanning from its position, otherwise we scan from the end
612 BasicBlock::iterator ScanPos = BB->end();
613 if (ExistingResult && ExistingResult->getInst()) {
614 assert(ExistingResult->getInst()->getParent() == BB &&
615 "Instruction invalidated?");
616 ++NumCacheDirtyNonLocalPtr;
617 ScanPos = ExistingResult->getInst();
619 // Eliminating the dirty entry from 'Cache', so update the reverse info.
620 ValueIsLoadPair CacheKey(Pointer, isLoad);
621 RemoveFromReverseMap(ReverseNonLocalPtrDeps, ScanPos, CacheKey);
623 ++NumUncacheNonLocalPtr;
626 // Scan the block for the dependency.
627 MemDepResult Dep = getPointerDependencyFrom(Pointer, PointeeSize, isLoad,
630 // If we had a dirty entry for the block, update it. Otherwise, just add
633 *ExistingResult = Dep;
635 Cache->push_back(std::make_pair(BB, Dep));
637 // If the block has a dependency (i.e. it isn't completely transparent to
638 // the value), remember the reverse association because we just added it
640 if (Dep.isNonLocal())
643 // Keep the ReverseNonLocalPtrDeps map up to date so we can efficiently
644 // update MemDep when we remove instructions.
645 Instruction *Inst = Dep.getInst();
646 assert(Inst && "Didn't depend on anything?");
647 ValueIsLoadPair CacheKey(Pointer, isLoad);
648 ReverseNonLocalPtrDeps[Inst].insert(CacheKey);
652 /// SortNonLocalDepInfoCache - Sort the a NonLocalDepInfo cache, given a certain
653 /// number of elements in the array that are already properly ordered. This is
654 /// optimized for the case when only a few entries are added.
656 SortNonLocalDepInfoCache(MemoryDependenceAnalysis::NonLocalDepInfo &Cache,
657 unsigned NumSortedEntries) {
658 switch (Cache.size() - NumSortedEntries) {
660 // done, no new entries.
663 // Two new entries, insert the last one into place.
664 MemoryDependenceAnalysis::NonLocalDepEntry Val = Cache.back();
666 MemoryDependenceAnalysis::NonLocalDepInfo::iterator Entry =
667 std::upper_bound(Cache.begin(), Cache.end()-1, Val);
668 Cache.insert(Entry, Val);
672 // One new entry, Just insert the new value at the appropriate position.
673 if (Cache.size() != 1) {
674 MemoryDependenceAnalysis::NonLocalDepEntry Val = Cache.back();
676 MemoryDependenceAnalysis::NonLocalDepInfo::iterator Entry =
677 std::upper_bound(Cache.begin(), Cache.end(), Val);
678 Cache.insert(Entry, Val);
682 // Added many values, do a full scale sort.
683 std::sort(Cache.begin(), Cache.end());
688 /// isPHITranslatable - Return true if the specified computation is derived from
689 /// a PHI node in the current block and if it is simple enough for us to handle.
690 static bool isPHITranslatable(Instruction *Inst) {
691 if (isa<PHINode>(Inst))
694 // We can handle bitcast of a PHI, but the PHI needs to be in the same block
696 if (BitCastInst *BC = dyn_cast<BitCastInst>(Inst))
697 if (PHINode *PN = dyn_cast<PHINode>(BC->getOperand(0)))
698 if (PN->getParent() == BC->getParent())
701 // We can translate a GEP that uses a PHI in the current block for at least
702 // one of its operands.
703 if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Inst)) {
704 for (unsigned i = 0, e = GEP->getNumOperands(); i != e; ++i)
705 if (PHINode *PN = dyn_cast<PHINode>(GEP->getOperand(i)))
706 if (PN->getParent() == GEP->getParent())
710 // cerr << "MEMDEP: Could not PHI translate: " << *Pointer;
711 // if (isa<BitCastInst>(PtrInst) || isa<GetElementPtrInst>(PtrInst))
712 // cerr << "OP:\t\t\t\t" << *PtrInst->getOperand(0);
717 /// PHITranslateForPred - Given a computation that satisfied the
718 /// isPHITranslatable predicate, see if we can translate the computation into
719 /// the specified predecessor block. If so, return that value.
720 Value *MemoryDependenceAnalysis::
721 PHITranslatePointer(Value *InVal, BasicBlock *CurBB, BasicBlock *Pred,
722 const TargetData *TD) const {
723 // If the input value is not an instruction, or if it is not defined in CurBB,
724 // then we don't need to phi translate it.
725 Instruction *Inst = dyn_cast<Instruction>(InVal);
726 if (Inst == 0 || Inst->getParent() != CurBB)
729 if (PHINode *PN = dyn_cast<PHINode>(Inst))
730 return PN->getIncomingValueForBlock(Pred);
732 // Handle bitcast of PHI.
733 if (BitCastInst *BC = dyn_cast<BitCastInst>(Inst)) {
734 PHINode *BCPN = cast<PHINode>(BC->getOperand(0));
735 Value *PHIIn = BCPN->getIncomingValueForBlock(Pred);
737 // Constants are trivial to phi translate.
738 if (Constant *C = dyn_cast<Constant>(PHIIn))
739 return ConstantExpr::getBitCast(C, BC->getType());
741 // Otherwise we have to see if a bitcasted version of the incoming pointer
742 // is available. If so, we can use it, otherwise we have to fail.
743 for (Value::use_iterator UI = PHIIn->use_begin(), E = PHIIn->use_end();
745 if (BitCastInst *BCI = dyn_cast<BitCastInst>(*UI))
746 if (BCI->getType() == BC->getType())
752 // Handle getelementptr with at least one PHI operand.
753 if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Inst)) {
754 SmallVector<Value*, 8> GEPOps;
756 BasicBlock *CurBB = GEP->getParent();
757 for (unsigned i = 0, e = GEP->getNumOperands(); i != e; ++i) {
758 GEPOps.push_back(GEP->getOperand(i)->DoPHITranslation(CurBB, Pred));
759 if (!isa<Constant>(GEPOps.back()))
760 APHIOp = GEPOps.back();
763 // Simplify the GEP to handle 'gep x, 0' -> x etc.
764 if (Value *V = SimplifyGEPInst(&GEPOps[0], GEPOps.size(), TD))
767 // Scan to see if we have this GEP available.
768 for (Value::use_iterator UI = APHIOp->use_begin(), E = APHIOp->use_end();
770 if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(*UI))
771 if (GEPI->getType() == GEP->getType() &&
772 GEPI->getNumOperands() == GEPOps.size() &&
773 GEPI->getParent()->getParent() == CurBB->getParent()) {
774 bool Mismatch = false;
775 for (unsigned i = 0, e = GEPOps.size(); i != e; ++i)
776 if (GEPI->getOperand(i) != GEPOps[i]) {
791 /// getNonLocalPointerDepFromBB - Perform a dependency query based on
792 /// pointer/pointeesize starting at the end of StartBB. Add any clobber/def
793 /// results to the results vector and keep track of which blocks are visited in
796 /// This has special behavior for the first block queries (when SkipFirstBlock
797 /// is true). In this special case, it ignores the contents of the specified
798 /// block and starts returning dependence info for its predecessors.
800 /// This function returns false on success, or true to indicate that it could
801 /// not compute dependence information for some reason. This should be treated
802 /// as a clobber dependence on the first instruction in the predecessor block.
803 bool MemoryDependenceAnalysis::
804 getNonLocalPointerDepFromBB(Value *Pointer, uint64_t PointeeSize,
805 bool isLoad, BasicBlock *StartBB,
806 SmallVectorImpl<NonLocalDepEntry> &Result,
807 DenseMap<BasicBlock*, Value*> &Visited,
808 bool SkipFirstBlock) {
810 // Look up the cached info for Pointer.
811 ValueIsLoadPair CacheKey(Pointer, isLoad);
813 std::pair<BBSkipFirstBlockPair, NonLocalDepInfo> *CacheInfo =
814 &NonLocalPointerDeps[CacheKey];
815 NonLocalDepInfo *Cache = &CacheInfo->second;
817 // If we have valid cached information for exactly the block we are
818 // investigating, just return it with no recomputation.
819 if (CacheInfo->first == BBSkipFirstBlockPair(StartBB, SkipFirstBlock)) {
820 // We have a fully cached result for this query then we can just return the
821 // cached results and populate the visited set. However, we have to verify
822 // that we don't already have conflicting results for these blocks. Check
823 // to ensure that if a block in the results set is in the visited set that
824 // it was for the same pointer query.
825 if (!Visited.empty()) {
826 for (NonLocalDepInfo::iterator I = Cache->begin(), E = Cache->end();
828 DenseMap<BasicBlock*, Value*>::iterator VI = Visited.find(I->first);
829 if (VI == Visited.end() || VI->second == Pointer) continue;
831 // We have a pointer mismatch in a block. Just return clobber, saying
832 // that something was clobbered in this result. We could also do a
833 // non-fully cached query, but there is little point in doing this.
838 for (NonLocalDepInfo::iterator I = Cache->begin(), E = Cache->end();
840 Visited.insert(std::make_pair(I->first, Pointer));
841 if (!I->second.isNonLocal())
842 Result.push_back(*I);
844 ++NumCacheCompleteNonLocalPtr;
848 // Otherwise, either this is a new block, a block with an invalid cache
849 // pointer or one that we're about to invalidate by putting more info into it
850 // than its valid cache info. If empty, the result will be valid cache info,
851 // otherwise it isn't.
853 CacheInfo->first = BBSkipFirstBlockPair(StartBB, SkipFirstBlock);
855 CacheInfo->first = BBSkipFirstBlockPair();
857 SmallVector<BasicBlock*, 32> Worklist;
858 Worklist.push_back(StartBB);
860 // Keep track of the entries that we know are sorted. Previously cached
861 // entries will all be sorted. The entries we add we only sort on demand (we
862 // don't insert every element into its sorted position). We know that we
863 // won't get any reuse from currently inserted values, because we don't
864 // revisit blocks after we insert info for them.
865 unsigned NumSortedEntries = Cache->size();
866 DEBUG(AssertSorted(*Cache));
868 while (!Worklist.empty()) {
869 BasicBlock *BB = Worklist.pop_back_val();
871 // Skip the first block if we have it.
872 if (!SkipFirstBlock) {
873 // Analyze the dependency of *Pointer in FromBB. See if we already have
875 assert(Visited.count(BB) && "Should check 'visited' before adding to WL");
877 // Get the dependency info for Pointer in BB. If we have cached
878 // information, we will use it, otherwise we compute it.
879 DEBUG(AssertSorted(*Cache, NumSortedEntries));
880 MemDepResult Dep = GetNonLocalInfoForBlock(Pointer, PointeeSize, isLoad,
881 BB, Cache, NumSortedEntries);
883 // If we got a Def or Clobber, add this to the list of results.
884 if (!Dep.isNonLocal()) {
885 Result.push_back(NonLocalDepEntry(BB, Dep));
890 // If 'Pointer' is an instruction defined in this block, then we need to do
891 // phi translation to change it into a value live in the predecessor block.
892 // If phi translation fails, then we can't continue dependence analysis.
893 Instruction *PtrInst = dyn_cast<Instruction>(Pointer);
894 bool NeedsPHITranslation = PtrInst && PtrInst->getParent() == BB;
896 // If no PHI translation is needed, just add all the predecessors of this
897 // block to scan them as well.
898 if (!NeedsPHITranslation) {
899 SkipFirstBlock = false;
900 for (BasicBlock **PI = PredCache->GetPreds(BB); *PI; ++PI) {
901 // Verify that we haven't looked at this block yet.
902 std::pair<DenseMap<BasicBlock*,Value*>::iterator, bool>
903 InsertRes = Visited.insert(std::make_pair(*PI, Pointer));
904 if (InsertRes.second) {
905 // First time we've looked at *PI.
906 Worklist.push_back(*PI);
910 // If we have seen this block before, but it was with a different
911 // pointer then we have a phi translation failure and we have to treat
912 // this as a clobber.
913 if (InsertRes.first->second != Pointer)
914 goto PredTranslationFailure;
919 // If we do need to do phi translation, then there are a bunch of different
920 // cases, because we have to find a Value* live in the predecessor block. We
921 // know that PtrInst is defined in this block at least.
923 // We may have added values to the cache list before this PHI translation.
924 // If so, we haven't done anything to ensure that the cache remains sorted.
925 // Sort it now (if needed) so that recursive invocations of
926 // getNonLocalPointerDepFromBB and other routines that could reuse the cache
927 // value will only see properly sorted cache arrays.
928 if (Cache && NumSortedEntries != Cache->size()) {
929 SortNonLocalDepInfoCache(*Cache, NumSortedEntries);
930 NumSortedEntries = Cache->size();
933 // If this is a computation derived from a PHI node, use the suitably
934 // translated incoming values for each pred as the phi translated version.
935 if (isPHITranslatable(PtrInst)) {
938 for (BasicBlock **PI = PredCache->GetPreds(BB); *PI; ++PI) {
939 BasicBlock *Pred = *PI;
940 Value *PredPtr = PHITranslatePointer(PtrInst, BB, Pred, TD);
942 // If PHI translation fails, bail out.
944 goto PredTranslationFailure;
946 // Check to see if we have already visited this pred block with another
947 // pointer. If so, we can't do this lookup. This failure can occur
948 // with PHI translation when a critical edge exists and the PHI node in
949 // the successor translates to a pointer value different than the
950 // pointer the block was first analyzed with.
951 std::pair<DenseMap<BasicBlock*,Value*>::iterator, bool>
952 InsertRes = Visited.insert(std::make_pair(Pred, PredPtr));
954 if (!InsertRes.second) {
955 // If the predecessor was visited with PredPtr, then we already did
956 // the analysis and can ignore it.
957 if (InsertRes.first->second == PredPtr)
960 // Otherwise, the block was previously analyzed with a different
961 // pointer. We can't represent the result of this case, so we just
962 // treat this as a phi translation failure.
963 goto PredTranslationFailure;
966 // FIXME: it is entirely possible that PHI translating will end up with
967 // the same value. Consider PHI translating something like:
968 // X = phi [x, bb1], [y, bb2]. PHI translating for bb1 doesn't *need*
969 // to recurse here, pedantically speaking.
971 // If we have a problem phi translating, fall through to the code below
972 // to handle the failure condition.
973 if (getNonLocalPointerDepFromBB(PredPtr, PointeeSize, isLoad, Pred,
975 goto PredTranslationFailure;
978 // Refresh the CacheInfo/Cache pointer so that it isn't invalidated.
979 CacheInfo = &NonLocalPointerDeps[CacheKey];
980 Cache = &CacheInfo->second;
981 NumSortedEntries = Cache->size();
983 // Since we did phi translation, the "Cache" set won't contain all of the
984 // results for the query. This is ok (we can still use it to accelerate
985 // specific block queries) but we can't do the fastpath "return all
986 // results from the set" Clear out the indicator for this.
987 CacheInfo->first = BBSkipFirstBlockPair();
988 SkipFirstBlock = false;
992 PredTranslationFailure:
995 // Refresh the CacheInfo/Cache pointer if it got invalidated.
996 CacheInfo = &NonLocalPointerDeps[CacheKey];
997 Cache = &CacheInfo->second;
998 NumSortedEntries = Cache->size();
1001 // Since we did phi translation, the "Cache" set won't contain all of the
1002 // results for the query. This is ok (we can still use it to accelerate
1003 // specific block queries) but we can't do the fastpath "return all
1004 // results from the set" Clear out the indicator for this.
1005 CacheInfo->first = BBSkipFirstBlockPair();
1007 // If *nothing* works, mark the pointer as being clobbered by the first
1008 // instruction in this block.
1010 // If this is the magic first block, return this as a clobber of the whole
1011 // incoming value. Since we can't phi translate to one of the predecessors,
1012 // we have to bail out.
1016 for (NonLocalDepInfo::reverse_iterator I = Cache->rbegin(); ; ++I) {
1017 assert(I != Cache->rend() && "Didn't find current block??");
1021 assert(I->second.isNonLocal() &&
1022 "Should only be here with transparent block");
1023 I->second = MemDepResult::getClobber(BB->begin());
1024 ReverseNonLocalPtrDeps[BB->begin()].insert(CacheKey);
1025 Result.push_back(*I);
1030 // Okay, we're done now. If we added new values to the cache, re-sort it.
1031 SortNonLocalDepInfoCache(*Cache, NumSortedEntries);
1032 DEBUG(AssertSorted(*Cache));
1036 /// RemoveCachedNonLocalPointerDependencies - If P exists in
1037 /// CachedNonLocalPointerInfo, remove it.
1038 void MemoryDependenceAnalysis::
1039 RemoveCachedNonLocalPointerDependencies(ValueIsLoadPair P) {
1040 CachedNonLocalPointerInfo::iterator It =
1041 NonLocalPointerDeps.find(P);
1042 if (It == NonLocalPointerDeps.end()) return;
1044 // Remove all of the entries in the BB->val map. This involves removing
1045 // instructions from the reverse map.
1046 NonLocalDepInfo &PInfo = It->second.second;
1048 for (unsigned i = 0, e = PInfo.size(); i != e; ++i) {
1049 Instruction *Target = PInfo[i].second.getInst();
1050 if (Target == 0) continue; // Ignore non-local dep results.
1051 assert(Target->getParent() == PInfo[i].first);
1053 // Eliminating the dirty entry from 'Cache', so update the reverse info.
1054 RemoveFromReverseMap(ReverseNonLocalPtrDeps, Target, P);
1057 // Remove P from NonLocalPointerDeps (which deletes NonLocalDepInfo).
1058 NonLocalPointerDeps.erase(It);
1062 /// invalidateCachedPointerInfo - This method is used to invalidate cached
1063 /// information about the specified pointer, because it may be too
1064 /// conservative in memdep. This is an optional call that can be used when
1065 /// the client detects an equivalence between the pointer and some other
1066 /// value and replaces the other value with ptr. This can make Ptr available
1067 /// in more places that cached info does not necessarily keep.
1068 void MemoryDependenceAnalysis::invalidateCachedPointerInfo(Value *Ptr) {
1069 // If Ptr isn't really a pointer, just ignore it.
1070 if (!isa<PointerType>(Ptr->getType())) return;
1071 // Flush store info for the pointer.
1072 RemoveCachedNonLocalPointerDependencies(ValueIsLoadPair(Ptr, false));
1073 // Flush load info for the pointer.
1074 RemoveCachedNonLocalPointerDependencies(ValueIsLoadPair(Ptr, true));
1077 /// removeInstruction - Remove an instruction from the dependence analysis,
1078 /// updating the dependence of instructions that previously depended on it.
1079 /// This method attempts to keep the cache coherent using the reverse map.
1080 void MemoryDependenceAnalysis::removeInstruction(Instruction *RemInst) {
1081 // Walk through the Non-local dependencies, removing this one as the value
1082 // for any cached queries.
1083 NonLocalDepMapType::iterator NLDI = NonLocalDeps.find(RemInst);
1084 if (NLDI != NonLocalDeps.end()) {
1085 NonLocalDepInfo &BlockMap = NLDI->second.first;
1086 for (NonLocalDepInfo::iterator DI = BlockMap.begin(), DE = BlockMap.end();
1088 if (Instruction *Inst = DI->second.getInst())
1089 RemoveFromReverseMap(ReverseNonLocalDeps, Inst, RemInst);
1090 NonLocalDeps.erase(NLDI);
1093 // If we have a cached local dependence query for this instruction, remove it.
1095 LocalDepMapType::iterator LocalDepEntry = LocalDeps.find(RemInst);
1096 if (LocalDepEntry != LocalDeps.end()) {
1097 // Remove us from DepInst's reverse set now that the local dep info is gone.
1098 if (Instruction *Inst = LocalDepEntry->second.getInst())
1099 RemoveFromReverseMap(ReverseLocalDeps, Inst, RemInst);
1101 // Remove this local dependency info.
1102 LocalDeps.erase(LocalDepEntry);
1105 // If we have any cached pointer dependencies on this instruction, remove
1106 // them. If the instruction has non-pointer type, then it can't be a pointer
1109 // Remove it from both the load info and the store info. The instruction
1110 // can't be in either of these maps if it is non-pointer.
1111 if (isa<PointerType>(RemInst->getType())) {
1112 RemoveCachedNonLocalPointerDependencies(ValueIsLoadPair(RemInst, false));
1113 RemoveCachedNonLocalPointerDependencies(ValueIsLoadPair(RemInst, true));
1116 // Loop over all of the things that depend on the instruction we're removing.
1118 SmallVector<std::pair<Instruction*, Instruction*>, 8> ReverseDepsToAdd;
1120 // If we find RemInst as a clobber or Def in any of the maps for other values,
1121 // we need to replace its entry with a dirty version of the instruction after
1122 // it. If RemInst is a terminator, we use a null dirty value.
1124 // Using a dirty version of the instruction after RemInst saves having to scan
1125 // the entire block to get to this point.
1126 MemDepResult NewDirtyVal;
1127 if (!RemInst->isTerminator())
1128 NewDirtyVal = MemDepResult::getDirty(++BasicBlock::iterator(RemInst));
1130 ReverseDepMapType::iterator ReverseDepIt = ReverseLocalDeps.find(RemInst);
1131 if (ReverseDepIt != ReverseLocalDeps.end()) {
1132 SmallPtrSet<Instruction*, 4> &ReverseDeps = ReverseDepIt->second;
1133 // RemInst can't be the terminator if it has local stuff depending on it.
1134 assert(!ReverseDeps.empty() && !isa<TerminatorInst>(RemInst) &&
1135 "Nothing can locally depend on a terminator");
1137 for (SmallPtrSet<Instruction*, 4>::iterator I = ReverseDeps.begin(),
1138 E = ReverseDeps.end(); I != E; ++I) {
1139 Instruction *InstDependingOnRemInst = *I;
1140 assert(InstDependingOnRemInst != RemInst &&
1141 "Already removed our local dep info");
1143 LocalDeps[InstDependingOnRemInst] = NewDirtyVal;
1145 // Make sure to remember that new things depend on NewDepInst.
1146 assert(NewDirtyVal.getInst() && "There is no way something else can have "
1147 "a local dep on this if it is a terminator!");
1148 ReverseDepsToAdd.push_back(std::make_pair(NewDirtyVal.getInst(),
1149 InstDependingOnRemInst));
1152 ReverseLocalDeps.erase(ReverseDepIt);
1154 // Add new reverse deps after scanning the set, to avoid invalidating the
1155 // 'ReverseDeps' reference.
1156 while (!ReverseDepsToAdd.empty()) {
1157 ReverseLocalDeps[ReverseDepsToAdd.back().first]
1158 .insert(ReverseDepsToAdd.back().second);
1159 ReverseDepsToAdd.pop_back();
1163 ReverseDepIt = ReverseNonLocalDeps.find(RemInst);
1164 if (ReverseDepIt != ReverseNonLocalDeps.end()) {
1165 SmallPtrSet<Instruction*, 4> &Set = ReverseDepIt->second;
1166 for (SmallPtrSet<Instruction*, 4>::iterator I = Set.begin(), E = Set.end();
1168 assert(*I != RemInst && "Already removed NonLocalDep info for RemInst");
1170 PerInstNLInfo &INLD = NonLocalDeps[*I];
1171 // The information is now dirty!
1174 for (NonLocalDepInfo::iterator DI = INLD.first.begin(),
1175 DE = INLD.first.end(); DI != DE; ++DI) {
1176 if (DI->second.getInst() != RemInst) continue;
1178 // Convert to a dirty entry for the subsequent instruction.
1179 DI->second = NewDirtyVal;
1181 if (Instruction *NextI = NewDirtyVal.getInst())
1182 ReverseDepsToAdd.push_back(std::make_pair(NextI, *I));
1186 ReverseNonLocalDeps.erase(ReverseDepIt);
1188 // Add new reverse deps after scanning the set, to avoid invalidating 'Set'
1189 while (!ReverseDepsToAdd.empty()) {
1190 ReverseNonLocalDeps[ReverseDepsToAdd.back().first]
1191 .insert(ReverseDepsToAdd.back().second);
1192 ReverseDepsToAdd.pop_back();
1196 // If the instruction is in ReverseNonLocalPtrDeps then it appears as a
1197 // value in the NonLocalPointerDeps info.
1198 ReverseNonLocalPtrDepTy::iterator ReversePtrDepIt =
1199 ReverseNonLocalPtrDeps.find(RemInst);
1200 if (ReversePtrDepIt != ReverseNonLocalPtrDeps.end()) {
1201 SmallPtrSet<ValueIsLoadPair, 4> &Set = ReversePtrDepIt->second;
1202 SmallVector<std::pair<Instruction*, ValueIsLoadPair>,8> ReversePtrDepsToAdd;
1204 for (SmallPtrSet<ValueIsLoadPair, 4>::iterator I = Set.begin(),
1205 E = Set.end(); I != E; ++I) {
1206 ValueIsLoadPair P = *I;
1207 assert(P.getPointer() != RemInst &&
1208 "Already removed NonLocalPointerDeps info for RemInst");
1210 NonLocalDepInfo &NLPDI = NonLocalPointerDeps[P].second;
1212 // The cache is not valid for any specific block anymore.
1213 NonLocalPointerDeps[P].first = BBSkipFirstBlockPair();
1215 // Update any entries for RemInst to use the instruction after it.
1216 for (NonLocalDepInfo::iterator DI = NLPDI.begin(), DE = NLPDI.end();
1218 if (DI->second.getInst() != RemInst) continue;
1220 // Convert to a dirty entry for the subsequent instruction.
1221 DI->second = NewDirtyVal;
1223 if (Instruction *NewDirtyInst = NewDirtyVal.getInst())
1224 ReversePtrDepsToAdd.push_back(std::make_pair(NewDirtyInst, P));
1227 // Re-sort the NonLocalDepInfo. Changing the dirty entry to its
1228 // subsequent value may invalidate the sortedness.
1229 std::sort(NLPDI.begin(), NLPDI.end());
1232 ReverseNonLocalPtrDeps.erase(ReversePtrDepIt);
1234 while (!ReversePtrDepsToAdd.empty()) {
1235 ReverseNonLocalPtrDeps[ReversePtrDepsToAdd.back().first]
1236 .insert(ReversePtrDepsToAdd.back().second);
1237 ReversePtrDepsToAdd.pop_back();
1242 assert(!NonLocalDeps.count(RemInst) && "RemInst got reinserted?");
1243 AA->deleteValue(RemInst);
1244 DEBUG(verifyRemoved(RemInst));
1246 /// verifyRemoved - Verify that the specified instruction does not occur
1247 /// in our internal data structures.
1248 void MemoryDependenceAnalysis::verifyRemoved(Instruction *D) const {
1249 for (LocalDepMapType::const_iterator I = LocalDeps.begin(),
1250 E = LocalDeps.end(); I != E; ++I) {
1251 assert(I->first != D && "Inst occurs in data structures");
1252 assert(I->second.getInst() != D &&
1253 "Inst occurs in data structures");
1256 for (CachedNonLocalPointerInfo::const_iterator I =NonLocalPointerDeps.begin(),
1257 E = NonLocalPointerDeps.end(); I != E; ++I) {
1258 assert(I->first.getPointer() != D && "Inst occurs in NLPD map key");
1259 const NonLocalDepInfo &Val = I->second.second;
1260 for (NonLocalDepInfo::const_iterator II = Val.begin(), E = Val.end();
1262 assert(II->second.getInst() != D && "Inst occurs as NLPD value");
1265 for (NonLocalDepMapType::const_iterator I = NonLocalDeps.begin(),
1266 E = NonLocalDeps.end(); I != E; ++I) {
1267 assert(I->first != D && "Inst occurs in data structures");
1268 const PerInstNLInfo &INLD = I->second;
1269 for (NonLocalDepInfo::const_iterator II = INLD.first.begin(),
1270 EE = INLD.first.end(); II != EE; ++II)
1271 assert(II->second.getInst() != D && "Inst occurs in data structures");
1274 for (ReverseDepMapType::const_iterator I = ReverseLocalDeps.begin(),
1275 E = ReverseLocalDeps.end(); I != E; ++I) {
1276 assert(I->first != D && "Inst occurs in data structures");
1277 for (SmallPtrSet<Instruction*, 4>::const_iterator II = I->second.begin(),
1278 EE = I->second.end(); II != EE; ++II)
1279 assert(*II != D && "Inst occurs in data structures");
1282 for (ReverseDepMapType::const_iterator I = ReverseNonLocalDeps.begin(),
1283 E = ReverseNonLocalDeps.end();
1285 assert(I->first != D && "Inst occurs in data structures");
1286 for (SmallPtrSet<Instruction*, 4>::const_iterator II = I->second.begin(),
1287 EE = I->second.end(); II != EE; ++II)
1288 assert(*II != D && "Inst occurs in data structures");
1291 for (ReverseNonLocalPtrDepTy::const_iterator
1292 I = ReverseNonLocalPtrDeps.begin(),
1293 E = ReverseNonLocalPtrDeps.end(); I != E; ++I) {
1294 assert(I->first != D && "Inst occurs in rev NLPD map");
1296 for (SmallPtrSet<ValueIsLoadPair, 4>::const_iterator II = I->second.begin(),
1297 E = I->second.end(); II != E; ++II)
1298 assert(*II != ValueIsLoadPair(D, false) &&
1299 *II != ValueIsLoadPair(D, true) &&
1300 "Inst occurs in ReverseNonLocalPtrDeps map");