diff options
Diffstat (limited to 'lib/Analysis/BasicAliasAnalysis.cpp')
| -rw-r--r-- | lib/Analysis/BasicAliasAnalysis.cpp | 29 |
1 files changed, 25 insertions, 4 deletions
diff --git a/lib/Analysis/BasicAliasAnalysis.cpp b/lib/Analysis/BasicAliasAnalysis.cpp index d958746359..d062045639 100644 --- a/lib/Analysis/BasicAliasAnalysis.cpp +++ b/lib/Analysis/BasicAliasAnalysis.cpp @@ -611,18 +611,39 @@ BasicAliasAnalysis::CheckGEPInstructions( if (G1OC != G2OC) { // Handle the "be careful" case above: if this is an array/vector // subscript, scan for a subsequent variable array index. - if (isa<SequentialType>(BasePtr1Ty)) { - const Type *NextTy = - cast<SequentialType>(BasePtr1Ty)->getElementType(); + if (const SequentialType *STy = + dyn_cast<SequentialType>(BasePtr1Ty)) { + const Type *NextTy = STy; bool isBadCase = false; - for (unsigned Idx = FirstConstantOper+1; + for (unsigned Idx = FirstConstantOper; Idx != MinOperands && isa<SequentialType>(NextTy); ++Idx) { const Value *V1 = GEP1Ops[Idx], *V2 = GEP2Ops[Idx]; if (!isa<Constant>(V1) || !isa<Constant>(V2)) { isBadCase = true; break; } + // If the array is indexed beyond the bounds of the static type + // at this level, it will also fall into the "be careful" case. + // It would theoretically be possible to analyze these cases, + // but for now just be conservatively correct. + if (const ArrayType *ATy = dyn_cast<ArrayType>(STy)) + if (cast<ConstantInt>(G1OC)->getZExtValue() >= + ATy->getNumElements() || + cast<ConstantInt>(G2OC)->getZExtValue() >= + ATy->getNumElements()) { + isBadCase = true; + break; + } + if (const VectorType *VTy = dyn_cast<VectorType>(STy)) + if (cast<ConstantInt>(G1OC)->getZExtValue() >= + VTy->getNumElements() || + cast<ConstantInt>(G2OC)->getZExtValue() >= + VTy->getNumElements()) { + isBadCase = true; + break; + } + STy = cast<SequentialType>(NextTy); NextTy = cast<SequentialType>(NextTy)->getElementType(); } |