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Properly handle volatile. 

llvm-svn: 19912
This commit is contained in:
Chris Lattner 2005-01-29 06:42:34 +00:00
parent a194357025
commit ce0fa4c109
1 changed files with 11 additions and 9 deletions
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20
llvm/lib/Analysis/LoadValueNumbering.cpp
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@ -299,12 +299,7 @@ void LoadVN::getEqualNumberNodes(Value *V,
bool LoadInvalidatedInBBBefore = false;
for (BasicBlock::iterator I = LI; I != LoadBB->begin(); ) {
--I;
// If this instruction is a candidate load before LI, we know there are no
// invalidating instructions between it and LI, so they have the same value
// number.
if (isa<LoadInst>(I) && cast<LoadInst>(I)->getOperand(0) == LoadPtr) {
RetVals.push_back(I);
} else if (I == LoadPtr) {
if (I == LoadPtr) {
// If we run into an allocation of the value being loaded, then the
// contents are not initialized.
if (isa<AllocationInst>(I))
@ -314,14 +309,21 @@ void LoadVN::getEqualNumberNodes(Value *V,
// loaded value cannot occur before this block.
LoadInvalidatedInBBBefore = true;
break;
} else if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
// If this instruction is a candidate load before LI, we know there are no
// invalidating instructions between it and LI, so they have the same
// value number.
if (LI->getOperand(0) == LoadPtr && !LI->isVolatile())
RetVals.push_back(I);
}
if (AA.getModRefInfo(I, LoadPtr, LoadSize) & AliasAnalysis::Mod) {
// If the invalidating instruction is a store, and its in our candidate
// set, then we can do store-load forwarding: the load has the same value
// # as the stored value.
if (isa<StoreInst>(I) && I->getOperand(1) == LoadPtr)
RetVals.push_back(I->getOperand(0));
if (StoreInst *SI = dyn_cast<StoreInst>(I))
if (SI->getOperand(1) == LoadPtr)
RetVals.push_back(I->getOperand(0));
LoadInvalidatedInBBBefore = true;
break;