Be more conservative in the face of volatile.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110456 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman 2010-08-06 18:11:28 +00:00
parent 9b8639c9bd
commit b9db52dcbc

View File

@ -195,31 +195,31 @@ AliasAnalysis::getModRefBehavior(const Function *F) {
AliasAnalysis::ModRefResult
AliasAnalysis::getModRefInfo(const LoadInst *L, const Value *P, unsigned Size) {
// Be conservative in the face of volatile.
if (L->isVolatile())
return ModRef;
// If the load address doesn't alias the given address, it doesn't read
// or write the specified memory.
if (!alias(L->getOperand(0), getTypeStoreSize(L->getType()), P, Size))
return NoModRef;
// Be conservative in the face of volatile.
if (L->isVolatile())
return ModRef;
// Otherwise, a load just reads.
return Ref;
}
AliasAnalysis::ModRefResult
AliasAnalysis::getModRefInfo(const StoreInst *S, const Value *P, unsigned Size) {
// Be conservative in the face of volatile.
if (S->isVolatile())
return ModRef;
// If the store address cannot alias the pointer in question, then the
// specified memory cannot be modified by the store.
if (!alias(S->getOperand(1),
getTypeStoreSize(S->getOperand(0)->getType()), P, Size))
return NoModRef;
// Be conservative in the face of volatile.
if (S->isVolatile())
return ModRef;
// If the pointer is a pointer to constant memory, then it could not have been
// modified by this store.
if (pointsToConstantMemory(P))