diff options
Diffstat (limited to 'lib/Analysis/BasicAliasAnalysis.cpp')
| -rw-r--r-- | lib/Analysis/BasicAliasAnalysis.cpp | 19 |
1 files changed, 9 insertions, 10 deletions
diff --git a/lib/Analysis/BasicAliasAnalysis.cpp b/lib/Analysis/BasicAliasAnalysis.cpp index dbb1b01b94ac2..b52a1d7b24d62 100644 --- a/lib/Analysis/BasicAliasAnalysis.cpp +++ b/lib/Analysis/BasicAliasAnalysis.cpp @@ -1021,11 +1021,14 @@ static AliasResult aliasSameBasePointerGEPs(const GEPOperator *GEP1, // 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. - KnownBits Known1 = computeKnownBits(GEP1LastIdx, DL); - KnownBits Known2 = computeKnownBits(GEP2LastIdx, DL); - if (Known1.Zero.intersects(Known2.One) || - Known1.One.intersects(Known2.Zero)) - return NoAlias; + 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)) return NoAlias; } @@ -1345,11 +1348,7 @@ AliasResult BasicAAResult::aliasGEP(const GEPOperator *GEP1, uint64_t V1Size, // Statically, we can see that the base objects are the same, but the // pointers have dynamic offsets which we can't resolve. And none of our // little tricks above worked. - // - // TODO: Returning PartialAlias instead of MayAlias is a mild hack; the - // practical effect of this is protecting TBAA in the case of dynamic - // indices into arrays of unions or malloc'd memory. - return PartialAlias; + return MayAlias; } static AliasResult MergeAliasResults(AliasResult A, AliasResult B) { |