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[InstCombine] use loop instead of recursion to peek through FPExt; NFCI 

llvm-svn: 295992
This commit is contained in:
Sanjay Patel 2017-02-23 16:39:51 +00:00
parent adf2ab16e4
commit 68e4cb3c86
1 changed files with 4 additions and 6 deletions
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10
llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
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@ -1223,17 +1223,15 @@ static Constant *fitsInFPType(ConstantFP *CFP, const fltSemantics &Sem) {
return nullptr;
}
/// If this is a floating-point extension instruction, look
/// through it until we get the source value.
/// Look through floating-point extensions until we get the source value.
static Value *lookThroughFPExtensions(Value *V) {
if (Instruction *I = dyn_cast<Instruction>(V))
if (I->getOpcode() == Instruction::FPExt)
return lookThroughFPExtensions(I->getOperand(0));
while (auto *FPExt = dyn_cast<FPExtInst>(V))
V = FPExt->getOperand(0);
// If this value is a constant, return the constant in the smallest FP type
// that can accurately represent it. This allows us to turn
// (float)((double)X+2.0) into x+2.0f.
if (ConstantFP *CFP = dyn_cast<ConstantFP>(V)) {
if (auto *CFP = dyn_cast<ConstantFP>(V)) {
if (CFP->getType() == Type::getPPC_FP128Ty(V->getContext()))
return V; // No constant folding of this.
// See if the value can be truncated to half and then reextended.