diff options
Diffstat (limited to 'llvm/lib/Analysis/BasicAliasAnalysis.cpp')
| -rw-r--r-- | llvm/lib/Analysis/BasicAliasAnalysis.cpp | 30 |
1 files changed, 9 insertions, 21 deletions
diff --git a/llvm/lib/Analysis/BasicAliasAnalysis.cpp b/llvm/lib/Analysis/BasicAliasAnalysis.cpp index 2fb353e..5e611a9 100644 --- a/llvm/lib/Analysis/BasicAliasAnalysis.cpp +++ b/llvm/lib/Analysis/BasicAliasAnalysis.cpp @@ -1032,11 +1032,11 @@ ModRefInfo BasicAAResult::getModRefInfo(const CallBase *Call1, /// Provide ad-hoc rules to disambiguate accesses through two GEP operators, /// both having the exact same pointer operand. -static AliasResult aliasSameBasePointerGEPs(const GEPOperator *GEP1, - LocationSize MaybeV1Size, - const GEPOperator *GEP2, - LocationSize MaybeV2Size, - const DataLayout &DL) { +AliasResult BasicAAResult::aliasSameBasePointerGEPs(const GEPOperator *GEP1, + LocationSize MaybeV1Size, + const GEPOperator *GEP2, + LocationSize MaybeV2Size, + const DataLayout &DL) { assert(GEP1->getPointerOperand()->stripPointerCastsAndInvariantGroups() == GEP2->getPointerOperand()->stripPointerCastsAndInvariantGroups() && GEP1->getPointerOperandType() == GEP2->getPointerOperandType() && @@ -1126,24 +1126,12 @@ static AliasResult aliasSameBasePointerGEPs(const GEPOperator *GEP1, if (C1 && C2) return NoAlias; { + // If we're not potentially reasoning about values from different + // iterations, see if we can prove them inequal. Value *GEP1LastIdx = GEP1->getOperand(GEP1->getNumOperands() - 1); Value *GEP2LastIdx = GEP2->getOperand(GEP2->getNumOperands() - 1); - if (isa<PHINode>(GEP1LastIdx) || isa<PHINode>(GEP2LastIdx)) { - // If one of the indices is a PHI node, be safe and only use - // computeKnownBits so we don't make any assumptions about the - // relationships between the two indices. This is important if we're - // asking about values from different loop iterations. See PR32314. - // TODO: We may be able to change the check so we only do this when - // we definitely looked through a PHINode. - if (GEP1LastIdx != GEP2LastIdx && - GEP1LastIdx->getType() == GEP2LastIdx->getType()) { - KnownBits Known1 = computeKnownBits(GEP1LastIdx, DL); - KnownBits Known2 = computeKnownBits(GEP2LastIdx, DL); - if (Known1.Zero.intersects(Known2.One) || - Known1.One.intersects(Known2.Zero)) - return NoAlias; - } - } else if (isKnownNonEqual(GEP1LastIdx, GEP2LastIdx, DL)) + if (VisitedPhiBBs.empty() && + isKnownNonEqual(GEP1LastIdx, GEP2LastIdx, DL)) return NoAlias; } } |