AAQueryInfo &AAQI) {
assert(notDifferentParent(LocA.Ptr, LocB.Ptr) &&
"BasicAliasAnalysis doesn't support interprocedural queries.");
- return aliasCheck(LocA.Ptr, LocA.Size, LocA.AATags, LocB.Ptr, LocB.Size,
- LocB.AATags, AAQI);
+
+ // If we have a directly cached entry for these locations, we have recursed
+ // through this once, so just return the cached results. Notably, when this
+ // happens, we don't clear the cache.
+ AAQueryInfo::LocPair Locs(LocA, LocB);
+ if (Locs.first.Ptr > Locs.second.Ptr)
+ std::swap(Locs.first, Locs.second);
+ auto CacheIt = AAQI.AliasCache.find(Locs);
+ if (CacheIt != AAQI.AliasCache.end()) {
+ // This code exists to skip a second BasicAA call while recursing into
+ // BestAA. Don't make use of assumptions here.
+ const auto &Entry = CacheIt->second;
+ return Entry.isDefinitive() ? Entry.Result : MayAlias;
+ }
+
+ AliasResult Alias = aliasCheck(LocA.Ptr, LocA.Size, LocA.AATags, LocB.Ptr,
+ LocB.Size, LocB.AATags, AAQI);
+
+ assert(VisitedPhiBBs.empty());
+ return Alias;
}
/// Checks to see if the specified callsite can clobber the specified memory
if (isGEPBaseAtNegativeOffset(GEP2, DecompGEP2, DecompGEP1, V1Size))
return NoAlias;
// Do the base pointers alias?
- AliasResult BaseAlias = getBestAAResults().alias(
- MemoryLocation::getBeforeOrAfter(UnderlyingV1),
- MemoryLocation::getBeforeOrAfter(UnderlyingV2), AAQI);
+ AliasResult BaseAlias = aliasCheck(
+ UnderlyingV1, LocationSize::beforeOrAfterPointer(), AAMDNodes(),
+ UnderlyingV2, LocationSize::beforeOrAfterPointer(), AAMDNodes(), AAQI);
// For GEPs with identical offsets, we can preserve the size and AAInfo
// when performing the alias check on the underlying objects.
if (BaseAlias == MayAlias && DecompGEP1.Offset == DecompGEP2.Offset &&
DecompGEP1.VarIndices == DecompGEP2.VarIndices) {
- AliasResult PreciseBaseAlias = getBestAAResults().alias(
- MemoryLocation(UnderlyingV1, V1Size, V1AAInfo),
- MemoryLocation(UnderlyingV2, V2Size, V2AAInfo), AAQI);
+ AliasResult PreciseBaseAlias = aliasCheck(
+ UnderlyingV1, V1Size, V1AAInfo, UnderlyingV2, V2Size, V2AAInfo, AAQI);
if (PreciseBaseAlias == NoAlias)
return NoAlias;
}
if (!V1Size.hasValue() && !V2Size.hasValue())
return MayAlias;
- AliasResult R = getBestAAResults().alias(
- MemoryLocation::getBeforeOrAfter(UnderlyingV1),
- MemoryLocation(V2, V2Size, V2AAInfo), AAQI);
+ AliasResult R = aliasCheck(
+ UnderlyingV1, LocationSize::beforeOrAfterPointer(), AAMDNodes(),
+ V2, V2Size, V2AAInfo, AAQI, nullptr, UnderlyingV2);
if (R != MustAlias) {
// If V2 may alias GEP base pointer, conservatively returns MayAlias.
// If V2 is known not to alias GEP base pointer, then the two values
BasicAAResult::aliasSelect(const SelectInst *SI, LocationSize SISize,
const AAMDNodes &SIAAInfo, const Value *V2,
LocationSize V2Size, const AAMDNodes &V2AAInfo,
- AAQueryInfo &AAQI) {
+ const Value *UnderV2, AAQueryInfo &AAQI) {
// If the values are Selects with the same condition, we can do a more precise
// check: just check for aliases between the values on corresponding arms.
if (const SelectInst *SI2 = dyn_cast<SelectInst>(V2))
if (SI->getCondition() == SI2->getCondition()) {
- AliasResult Alias = getBestAAResults().alias(
- MemoryLocation(SI->getTrueValue(), SISize, SIAAInfo),
- MemoryLocation(SI2->getTrueValue(), V2Size, V2AAInfo), AAQI);
+ AliasResult Alias =
+ aliasCheck(SI->getTrueValue(), SISize, SIAAInfo, SI2->getTrueValue(),
+ V2Size, V2AAInfo, AAQI);
if (Alias == MayAlias)
return MayAlias;
- AliasResult ThisAlias = getBestAAResults().alias(
- MemoryLocation(SI->getFalseValue(), SISize, SIAAInfo),
- MemoryLocation(SI2->getFalseValue(), V2Size, V2AAInfo), AAQI);
+ AliasResult ThisAlias =
+ aliasCheck(SI->getFalseValue(), SISize, SIAAInfo,
+ SI2->getFalseValue(), V2Size, V2AAInfo, AAQI);
return MergeAliasResults(ThisAlias, Alias);
}
// If both arms of the Select node NoAlias or MustAlias V2, then returns
// NoAlias / MustAlias. Otherwise, returns MayAlias.
- AliasResult Alias = getBestAAResults().alias(
- MemoryLocation(V2, V2Size, V2AAInfo),
- MemoryLocation(SI->getTrueValue(), SISize, SIAAInfo), AAQI);
+ AliasResult Alias = aliasCheck(V2, V2Size, V2AAInfo, SI->getTrueValue(),
+ SISize, SIAAInfo, AAQI, UnderV2);
if (Alias == MayAlias)
return MayAlias;
- AliasResult ThisAlias = getBestAAResults().alias(
- MemoryLocation(V2, V2Size, V2AAInfo),
- MemoryLocation(SI->getFalseValue(), SISize, SIAAInfo), AAQI);
+ AliasResult ThisAlias = aliasCheck(V2, V2Size, V2AAInfo, SI->getFalseValue(),
+ SISize, SIAAInfo, AAQI, UnderV2);
return MergeAliasResults(ThisAlias, Alias);
}
const AAMDNodes &PNAAInfo, const Value *V2,
LocationSize V2Size,
const AAMDNodes &V2AAInfo,
- AAQueryInfo &AAQI) {
+ const Value *UnderV2, AAQueryInfo &AAQI) {
// If the values are PHIs in the same block, we can do a more precise
// as well as efficient check: just check for aliases between the values
// on corresponding edges.
if (PN2->getParent() == PN->getParent()) {
Optional<AliasResult> Alias;
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
- AliasResult ThisAlias = getBestAAResults().alias(
- MemoryLocation(PN->getIncomingValue(i), PNSize, PNAAInfo),
- MemoryLocation(
- PN2->getIncomingValueForBlock(PN->getIncomingBlock(i)), V2Size,
- V2AAInfo),
- AAQI);
+ AliasResult ThisAlias =
+ aliasCheck(PN->getIncomingValue(i), PNSize, PNAAInfo,
+ PN2->getIncomingValueForBlock(PN->getIncomingBlock(i)),
+ V2Size, V2AAInfo, AAQI);
if (Alias)
*Alias = MergeAliasResults(*Alias, ThisAlias);
else
AAQueryInfo NewAAQI;
AAQueryInfo *UseAAQI = BlockInserted ? &NewAAQI : &AAQI;
- AliasResult Alias = getBestAAResults().alias(
- MemoryLocation(V2, V2Size, V2AAInfo),
- MemoryLocation(V1Srcs[0], PNSize, PNAAInfo), *UseAAQI);
+ AliasResult Alias = aliasCheck(V2, V2Size, V2AAInfo, V1Srcs[0], PNSize,
+ PNAAInfo, *UseAAQI, UnderV2);
// Early exit if the check of the first PHI source against V2 is MayAlias.
// Other results are not possible.
for (unsigned i = 1, e = V1Srcs.size(); i != e; ++i) {
Value *V = V1Srcs[i];
- AliasResult ThisAlias = getBestAAResults().alias(
- MemoryLocation(V2, V2Size, V2AAInfo),
- MemoryLocation(V, PNSize, PNAAInfo), *UseAAQI);
+ AliasResult ThisAlias = aliasCheck(V2, V2Size, V2AAInfo, V, PNSize,
+ PNAAInfo, *UseAAQI, UnderV2);
Alias = MergeAliasResults(ThisAlias, Alias);
if (Alias == MayAlias)
break;
const AAMDNodes &V1AAInfo,
const Value *V2, LocationSize V2Size,
const AAMDNodes &V2AAInfo,
- AAQueryInfo &AAQI) {
+ AAQueryInfo &AAQI, const Value *O1,
+ const Value *O2) {
// If either of the memory references is empty, it doesn't matter what the
// pointer values are.
if (V1Size.isZero() || V2Size.isZero())
return NoAlias; // Scalars cannot alias each other
// Figure out what objects these things are pointing to if we can.
- const Value *O1 = getUnderlyingObject(V1, MaxLookupSearchDepth);
- const Value *O2 = getUnderlyingObject(V2, MaxLookupSearchDepth);
+ if (O1 == nullptr)
+ O1 = getUnderlyingObject(V1, MaxLookupSearchDepth);
+
+ if (O2 == nullptr)
+ O2 = getUnderlyingObject(V2, MaxLookupSearchDepth);
// Null values in the default address space don't point to any object, so they
// don't alias any other pointer.
if (const PHINode *PN = dyn_cast<PHINode>(V1)) {
AliasResult Result =
- aliasPHI(PN, V1Size, V1AAInfo, V2, V2Size, V2AAInfo, AAQI);
+ aliasPHI(PN, V1Size, V1AAInfo, V2, V2Size, V2AAInfo, O2, AAQI);
if (Result != MayAlias)
return Result;
} else if (const PHINode *PN = dyn_cast<PHINode>(V2)) {
AliasResult Result =
- aliasPHI(PN, V2Size, V2AAInfo, V1, V1Size, V1AAInfo, AAQI);
+ aliasPHI(PN, V2Size, V2AAInfo, V1, V1Size, V1AAInfo, O1, AAQI);
if (Result != MayAlias)
return Result;
}
if (const SelectInst *S1 = dyn_cast<SelectInst>(V1)) {
AliasResult Result =
- aliasSelect(S1, V1Size, V1AAInfo, V2, V2Size, V2AAInfo, AAQI);
+ aliasSelect(S1, V1Size, V1AAInfo, V2, V2Size, V2AAInfo, O2, AAQI);
if (Result != MayAlias)
return Result;
} else if (const SelectInst *S2 = dyn_cast<SelectInst>(V2)) {
AliasResult Result =
- aliasSelect(S2, V2Size, V2AAInfo, V1, V1Size, V1AAInfo, AAQI);
+ aliasSelect(S2, V2Size, V2AAInfo, V1, V1Size, V1AAInfo, O1, AAQI);
if (Result != MayAlias)
return Result;
}
return PartialAlias;
}
- return MayAlias;
+ // Recurse back into the best AA results we have, potentially with refined
+ // memory locations. We have already ensured that BasicAA has a MayAlias
+ // cache result for these, so any recursion back into BasicAA won't loop.
+ return getBestAAResults().alias(MemoryLocation(V1, V1Size, V1AAInfo),
+ MemoryLocation(V2, V2Size, V2AAInfo), AAQI);
}
/// Check whether two Values can be considered equivalent.