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Don't DSe volatile stores. 

llvm-svn: 41456
This commit is contained in:
Owen Anderson 2007-08-26 21:14:47 +00:00
parent dd9a319158
commit 2b9ec7ff33
1 changed files with 25 additions and 18 deletions
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43
llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
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@ -111,9 +111,12 @@ bool DSE::runOnBasicBlock(BasicBlock &BB) {
continue;
Value* pointer = 0;
if (StoreInst* S = dyn_cast<StoreInst>(BBI))
pointer = S->getPointerOperand();
else
if (StoreInst* S = dyn_cast<StoreInst>(BBI)) {
if (!S->isVolatile())
pointer = S->getPointerOperand();
else
continue;
} else
pointer = cast<FreeInst>(BBI)->getPointerOperand();
StoreInst*& last = lastStore[pointer];
@ -194,6 +197,8 @@ bool DSE::handleFreeWithNonTrivialDependency(FreeInst* F, Instruction* dep,
StoreInst* dependency = dyn_cast<StoreInst>(dep);
if (!dependency)
return false;
else if (dependency->isVolatile())
return false;
Value* depPointer = dependency->getPointerOperand();
const Type* depType = dependency->getOperand(0)->getType();
@ -253,24 +258,26 @@ bool DSE::handleEndBlock(BasicBlock& BB,
// If we find a store whose pointer is dead...
if (StoreInst* S = dyn_cast<StoreInst>(BBI)) {
Value* pointerOperand = S->getPointerOperand();
// See through pointer-to-pointer bitcasts
TranslatePointerBitCasts(pointerOperand);
if (!S->isVolatile()) {
Value* pointerOperand = S->getPointerOperand();
// See through pointer-to-pointer bitcasts
TranslatePointerBitCasts(pointerOperand);
if (deadPointers.count(pointerOperand)){
// Remove it!
MD.removeInstruction(S);
if (deadPointers.count(pointerOperand)){
// Remove it!
MD.removeInstruction(S);
// DCE instructions only used to calculate that store
if (Instruction* D = dyn_cast<Instruction>(S->getOperand(0)))
possiblyDead.insert(D);
if (Instruction* D = dyn_cast<Instruction>(S->getOperand(1)))
possiblyDead.insert(D);
// DCE instructions only used to calculate that store
if (Instruction* D = dyn_cast<Instruction>(S->getOperand(0)))
possiblyDead.insert(D);
if (Instruction* D = dyn_cast<Instruction>(S->getOperand(1)))
possiblyDead.insert(D);
BBI++;
S->eraseFromParent();
NumFastStores++;
MadeChange = true;
BBI++;
S->eraseFromParent();
NumFastStores++;
MadeChange = true;
}
}
continue;