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Fix bug: BasicAA/2003-03-04-GEPCrash.ll 

llvm-svn: 5695
This commit is contained in:
Chris Lattner 2003-03-04 16:40:17 +00:00
parent fa9cdda3c4
commit ce848a3397
1 changed files with 11 additions and 17 deletions
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28
llvm/lib/Analysis/BasicAliasAnalysis.cpp
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@ -274,24 +274,18 @@ BasicAliasAnalysis::CheckGEPInstructions(GetElementPtrInst *GEP1, unsigned G1S,
Indices1.push_back((Value*)Op1);
else {
// GEP1 is known to produce a value less than GEP2. To be
// conservatively correct, we must assume the largest
// possible constant is used in this position. This cannot
// be the initial index to the GEP instructions (because we
// know we have at least one element before this one with
// the different constant arguments), so we know that the
// current index must be into either a struct or array.
// Because of this, we can calculate the maximum value
// possible.
// conservatively correct, we must assume the largest possible constant
// is used in this position. This cannot be the initial index to the
// GEP instructions (because we know we have at least one element before
// this one with the different constant arguments), so we know that the
// current index must be into either a struct or array. Because we know
// it's not constant, this cannot be a structure index. Because of
// this, we can calculate the maximum value possible.
//
const Type *ElTy = GEP1->getIndexedType(GEPPointerTy,
Indices1, true);
if (const StructType *STy = dyn_cast<StructType>(ElTy)) {
Indices1.push_back(ConstantUInt::get(Type::UByteTy,
STy->getNumContainedTypes()));
} else {
Indices1.push_back(ConstantSInt::get(Type::LongTy,
cast<ArrayType>(ElTy)->getNumElements()));
}
const ArrayType *ElTy =
cast<ArrayType>(GEP1->getIndexedType(GEPPointerTy, Indices1, true));
Indices1.push_back(ConstantSInt::get(Type::LongTy,
ElTy->getNumElements()-1));
}
if (isa<Constant>(Op2))