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rename a function and reduce some indentation, no functionality change. 

llvm-svn: 120391
This commit is contained in:
Chris Lattner 2010-11-30 05:30:45 +00:00
parent 936a5b44ee
commit 3590ef817c
1 changed files with 21 additions and 19 deletions
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40
llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
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@ -111,9 +111,9 @@ static bool hasMemoryWrite(Instruction *I) {
return false; return false;
} }
/// isElidable - If the value of this instruction and the memory it writes to is /// isRemovable - If the value of this instruction and the memory it writes to
/// unused, may we delete this instrtction? /// is unused, may we delete this instruction?
static bool isElidable(Instruction *I) { static bool isRemovable(Instruction *I) {
assert(hasMemoryWrite(I)); assert(hasMemoryWrite(I));
if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I))
return II->getIntrinsicID() != Intrinsic::lifetime_end; return II->getIntrinsicID() != Intrinsic::lifetime_end;
@ -192,6 +192,7 @@ static bool isStoreAtLeastAsWideAs(Instruction *I1, Instruction *I2,
bool DSE::runOnBasicBlock(BasicBlock &BB) { bool DSE::runOnBasicBlock(BasicBlock &BB) {
MemoryDependenceAnalysis &MD = getAnalysis<MemoryDependenceAnalysis>(); MemoryDependenceAnalysis &MD = getAnalysis<MemoryDependenceAnalysis>();
AliasAnalysis &AA = getAnalysis<AliasAnalysis>();
TD = getAnalysisIfAvailable<TargetData>(); TD = getAnalysisIfAvailable<TargetData>();
bool MadeChange = false; bool MadeChange = false;
@ -238,7 +239,7 @@ bool DSE::runOnBasicBlock(BasicBlock &BB) {
} }
} }
} }
if (!InstDep.isDef()) { if (!InstDep.isDef()) {
// If this is a may-aliased store that is clobbering the store value, we // If this is a may-aliased store that is clobbering the store value, we
// can keep searching past it for another must-aliased pointer that stores // can keep searching past it for another must-aliased pointer that stores
@ -249,7 +250,6 @@ bool DSE::runOnBasicBlock(BasicBlock &BB) {
// we can remove the first store to P even though we don't know if P and Q // we can remove the first store to P even though we don't know if P and Q
// alias. // alias.
if (StoreInst *SI = dyn_cast<StoreInst>(Inst)) { if (StoreInst *SI = dyn_cast<StoreInst>(Inst)) {
AliasAnalysis &AA = getAnalysis<AliasAnalysis>();
AliasAnalysis::Location Loc = AA.getLocation(SI); AliasAnalysis::Location Loc = AA.getLocation(SI);
while (InstDep.isClobber() && InstDep.getInst() != &BB.front()) { while (InstDep.isClobber() && InstDep.getInst() != &BB.front()) {
// Can't look past this instruction if it might read 'Loc'. // Can't look past this instruction if it might read 'Loc'.
@ -266,19 +266,21 @@ bool DSE::runOnBasicBlock(BasicBlock &BB) {
// long as this store is at least as big as it. // long as this store is at least as big as it.
if (InstDep.isDef() && hasMemoryWrite(InstDep.getInst())) { if (InstDep.isDef() && hasMemoryWrite(InstDep.getInst())) {
Instruction *DepStore = InstDep.getInst(); Instruction *DepStore = InstDep.getInst();
if (isStoreAtLeastAsWideAs(Inst, DepStore, TD) && isElidable(DepStore)) { if (!isRemovable(DepStore) ||
// Delete the store and now-dead instructions that feed it. !isStoreAtLeastAsWideAs(Inst, DepStore, TD))
DeleteDeadInstruction(DepStore);
++NumFastStores;
MadeChange = true;
// DeleteDeadInstruction can delete the current instruction in loop
// cases, reset BBI.
BBI = Inst;
if (BBI != BB.begin())
--BBI;
continue; continue;
}
// Delete the store and now-dead instructions that feed it.
DeleteDeadInstruction(DepStore);
++NumFastStores;
MadeChange = true;
// DeleteDeadInstruction can delete the current instruction in loop
// cases, reset BBI.
BBI = Inst;
if (BBI != BB.begin())
--BBI;
continue;
} }
} }
@ -301,7 +303,7 @@ bool DSE::HandleFree(CallInst *F) {
if (Dep.isNonLocal()) return false; if (Dep.isNonLocal()) return false;
Instruction *Dependency = Dep.getInst(); Instruction *Dependency = Dep.getInst();
if (!hasMemoryWrite(Dependency) || !isElidable(Dependency)) if (!hasMemoryWrite(Dependency) || !isRemovable(Dependency))
return false; return false;
Value *DepPointer = getPointerOperand(Dependency)->getUnderlyingObject(); Value *DepPointer = getPointerOperand(Dependency)->getUnderlyingObject();
@ -359,7 +361,7 @@ bool DSE::handleEndBlock(BasicBlock &BB) {
// If we find a store whose pointer is dead. // If we find a store whose pointer is dead.
if (hasMemoryWrite(BBI)) { if (hasMemoryWrite(BBI)) {
if (isElidable(BBI)) { if (isRemovable(BBI)) {
// See through pointer-to-pointer bitcasts // See through pointer-to-pointer bitcasts
Value *pointerOperand = getPointerOperand(BBI)->getUnderlyingObject(); Value *pointerOperand = getPointerOperand(BBI)->getUnderlyingObject();