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performance: cache the dereferenced use_iterator

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@101265 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Gabor Greif 2010-04-14 18:13:29 +00:00
parent 988099700a
commit 6ed58e0d16
1 changed files with 8 additions and 7 deletions
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15
lib/Analysis/InlineCost.cpp
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@ -24,28 +24,29 @@ using namespace llvm;
unsigned InlineCostAnalyzer::FunctionInfo::
CountCodeReductionForConstant(Value *V) {
unsigned Reduction = 0;
for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E; ++UI)
if (isa<BranchInst>(*UI) || isa<SwitchInst>(*UI)) {
for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E;++UI){
User *U = *UI;
if (isa<BranchInst>(U) || isa<SwitchInst>(U)) {
// We will be able to eliminate all but one of the successors.
const TerminatorInst &TI = cast<TerminatorInst>(**UI);
const TerminatorInst &TI = cast<TerminatorInst>(*U);
const unsigned NumSucc = TI.getNumSuccessors();
unsigned Instrs = 0;
for (unsigned I = 0; I != NumSucc; ++I)
Instrs += Metrics.NumBBInsts[TI.getSuccessor(I)];
// We don't know which blocks will be eliminated, so use the average size.
Reduction += InlineConstants::InstrCost*Instrs*(NumSucc-1)/NumSucc;
} else if (CallInst *CI = dyn_cast<CallInst>(*UI)) {
} else if (CallInst *CI = dyn_cast<CallInst>(U)) {
// Turning an indirect call into a direct call is a BIG win
if (CI->getCalledValue() == V)
Reduction += InlineConstants::IndirectCallBonus;
} else if (InvokeInst *II = dyn_cast<InvokeInst>(*UI)) {
} else if (InvokeInst *II = dyn_cast<InvokeInst>(U)) {
// Turning an indirect call into a direct call is a BIG win
if (II->getCalledValue() == V)
Reduction += InlineConstants::IndirectCallBonus;
} else {
// Figure out if this instruction will be removed due to simple constant
// propagation.
Instruction &Inst = cast<Instruction>(**UI);
Instruction &Inst = cast<Instruction>(*U);
// We can't constant propagate instructions which have effects or
// read memory.
@ -74,7 +75,7 @@ CountCodeReductionForConstant(Value *V) {
Reduction += CountCodeReductionForConstant(&Inst);
}
}
}
return Reduction;
}