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Revert "r214897 - Remove dead zero store to calloc initialized memory"

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It broke msan.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214989 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Rui Ueyama
2014-08-06 19:30:38 +00:00
parent 41612a9b85
commit 2764f3ded3
2 changed files with 15 additions and 52 deletions
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50
lib/Transforms/Scalar/DeadStoreElimination.cpp
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@@ -514,49 +514,29 @@ bool DSE::runOnBasicBlock(BasicBlock &BB) {
if (!InstDep.isDef() && !InstDep.isClobber())
continue;
// Check for cases where the store is redundant.
// If we're storing the same value back to a pointer that we just
// loaded from, then the store can be removed.
if (StoreInst *SI = dyn_cast<StoreInst>(Inst)) {
bool DeleteStore = false;
// If we're storing the same value back to a pointer that we just
// loaded from, then the store can be removed.
if (LoadInst *DepLoad = dyn_cast<LoadInst>(InstDep.getInst())) {
if (SI->getPointerOperand() == DepLoad->getPointerOperand() &&
SI->getOperand(0) == DepLoad && isRemovable(SI)) {
DEBUG(dbgs() << "DSE: Remove Store Of Load from same pointer:\n "
<< "LOAD: " << *DepLoad << "\n STORE: " << *SI << '\n');
DeleteStore = true;
}
}
// If we find a store to memory which was defined by calloc
// we can remove the store if the value being stored is a
// constant zero (since calloc initialized the memory to
// that same value) or the store is undefined (if out of
// bounds).
if (isCallocLikeFn(InstDep.getInst(), TLI) && isRemovable(SI)) {
Value *V = SI->getValueOperand();
if (isa<Constant>(V) && cast<Constant>(V)->isNullValue()) {
DEBUG(dbgs() << "DSE: Remove Store Of Zero to Calloc:\n "
<< "CALLOC: " << *InstDep.getInst() << "\n"
<< "STORE: " << *SI << '\n');
DeleteStore = true;
}
}
// DeleteDeadInstruction can delete the current instruction. Save BBI
// in case we need it.
WeakVH NextInst(BBI);
if (DeleteStore) {
// DeleteDeadInstruction can delete the current instruction. Save BBI
// in case we need it.
WeakVH NextInst(BBI);
DeleteDeadInstruction(SI, *MD, TLI);
if (!NextInst) // Next instruction deleted.
BBI = BB.begin();
else if (BBI != BB.begin()) // Revisit this instruction if possible.
--BBI;
++NumFastStores;
MadeChange = true;
continue;
DeleteDeadInstruction(SI, *MD, TLI);
if (!NextInst) // Next instruction deleted.
BBI = BB.begin();
else if (BBI != BB.begin()) // Revisit this instruction if possible.
--BBI;
++NumFastStores;
MadeChange = true;
continue;
}
}
}