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performance: get rid of repeated dereferencing of use_iterator by caching its result 

llvm-svn: 100550
This commit is contained in:
Gabor Greif 2010-04-06 19:32:30 +00:00
parent 679728790b
commit df323a51f5
1 changed files with 7 additions and 5 deletions
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12
llvm/lib/Transforms/Scalar/ScalarReplAggregates.cpp
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@ -1702,18 +1702,20 @@ static bool PointsToConstantGlobal(Value *V) {
static bool isOnlyCopiedFromConstantGlobal(Value *V, Instruction *&TheCopy, static bool isOnlyCopiedFromConstantGlobal(Value *V, Instruction *&TheCopy,
bool isOffset) { bool isOffset) {
for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI!=E; ++UI) { for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI!=E; ++UI) {
if (LoadInst *LI = dyn_cast<LoadInst>(*UI)) User *U = cast<Instruction>(*UI);
if (LoadInst *LI = dyn_cast<LoadInst>(U))
// Ignore non-volatile loads, they are always ok. // Ignore non-volatile loads, they are always ok.
if (!LI->isVolatile()) if (!LI->isVolatile())
continue; continue;
if (BitCastInst *BCI = dyn_cast<BitCastInst>(*UI)) { if (BitCastInst *BCI = dyn_cast<BitCastInst>(U)) {
// If uses of the bitcast are ok, we are ok. // If uses of the bitcast are ok, we are ok.
if (!isOnlyCopiedFromConstantGlobal(BCI, TheCopy, isOffset)) if (!isOnlyCopiedFromConstantGlobal(BCI, TheCopy, isOffset))
return false; return false;
continue; continue;
} }
if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(*UI)) { if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(U)) {
// If the GEP has all zero indices, it doesn't offset the pointer. If it // If the GEP has all zero indices, it doesn't offset the pointer. If it
// doesn't, it does. // doesn't, it does.
if (!isOnlyCopiedFromConstantGlobal(GEP, TheCopy, if (!isOnlyCopiedFromConstantGlobal(GEP, TheCopy,
@ -1724,7 +1726,7 @@ static bool isOnlyCopiedFromConstantGlobal(Value *V, Instruction *&TheCopy,
// If this is isn't our memcpy/memmove, reject it as something we can't // If this is isn't our memcpy/memmove, reject it as something we can't
// handle. // handle.
if (!isa<MemTransferInst>(*UI)) if (!isa<MemTransferInst>(U))
return false; return false;
// If we already have seen a copy, reject the second one. // If we already have seen a copy, reject the second one.
@ -1737,7 +1739,7 @@ static bool isOnlyCopiedFromConstantGlobal(Value *V, Instruction *&TheCopy,
// If the memintrinsic isn't using the alloca as the dest, reject it. // If the memintrinsic isn't using the alloca as the dest, reject it.
if (UI.getOperandNo() != 1) return false; if (UI.getOperandNo() != 1) return false;
MemIntrinsic *MI = cast<MemIntrinsic>(*UI); MemIntrinsic *MI = cast<MemIntrinsic>(U);
// If the source of the memcpy/move is not a constant global, reject it. // If the source of the memcpy/move is not a constant global, reject it.
if (!PointsToConstantGlobal(MI->getOperand(2))) if (!PointsToConstantGlobal(MI->getOperand(2)))