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[InstCombine] rearrange code for fcmp+fpext; NFCI 

llvm-svn: 346241
This commit is contained in:
Sanjay Patel 2018-11-06 16:37:35 +00:00
parent 1b85f00201
commit 7c3ee4da42
1 changed files with 27 additions and 29 deletions
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56
llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
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@ -5409,29 +5409,6 @@ Instruction *InstCombiner::visitFCmpInst(FCmpInst &I) {
Constant *RHSC;
if (match(Op0, m_Instruction(LHSI)) && match(Op1, m_Constant(RHSC))) {
switch (LHSI->getOpcode()) {
case Instruction::FPExt: {
// fcmp (fpext x), C -> fcmp x, (fptrunc C) if fptrunc is lossless
FPExtInst *LHSExt = cast<FPExtInst>(LHSI);
ConstantFP *RHSF = dyn_cast<ConstantFP>(RHSC);
if (!RHSF)
break;
const fltSemantics &FPSem = LHSExt->getSrcTy()->getFltSemantics();
bool Lossy;
APFloat F = RHSF->getValueAPF();
F.convert(FPSem, APFloat::rmNearestTiesToEven, &Lossy);
// Avoid lossy conversions and denormals.
// Zero is a special case that's OK to convert.
APFloat Fabs = F;
Fabs.clearSign();
if (!Lossy &&
((Fabs.compare(APFloat::getSmallestNormalized(FPSem)) !=
APFloat::cmpLessThan) || Fabs.isZero()))
return new FCmpInst(Pred, LHSExt->getOperand(0),
ConstantFP::get(RHSC->getContext(), F));
break;
}
case Instruction::PHI:
// Only fold fcmp into the PHI if the phi and fcmp are in the same
// block. If in the same block, we're encouraging jump threading. If
@ -5483,12 +5460,33 @@ Instruction *InstCombiner::visitFCmpInst(FCmpInst &I) {
}
}
// fcmp (fpext X), (fpext Y) -> fcmp X, Y
if (match(Op0, m_FPExt(m_Value(X))) && match(Op1, m_FPExt(m_Value(Y))) &&
X->getType() == Y->getType()) {
Instruction *NewFCmp = new FCmpInst(Pred, X, Y);
NewFCmp->copyFastMathFlags(&I);
return NewFCmp;
if (match(Op0, m_FPExt(m_Value(X)))) {
if (match(Op1, m_FPExt(m_Value(Y))) && X->getType() == Y->getType()) {
// fcmp (fpext X), (fpext Y) -> fcmp X, Y
Instruction *NewFCmp = new FCmpInst(Pred, X, Y);
NewFCmp->copyFastMathFlags(&I);
return NewFCmp;
}
// TODO: Use m_APFloat to handle vector splats.
ConstantFP *C;
if (match(Op1, m_ConstantFP(C))) {
// fcmp (fpext X), C -> fcmp X, (fptrunc C) if fptrunc is lossless
const fltSemantics &FPSem = X->getType()->getFltSemantics();
bool Lossy;
APFloat F = C->getValueAPF();
F.convert(FPSem, APFloat::rmNearestTiesToEven, &Lossy);
// Avoid lossy conversions and denormals.
// Zero is a special case that's OK to convert.
APFloat Fabs = F;
Fabs.clearSign();
if (!Lossy &&
((Fabs.compare(APFloat::getSmallestNormalized(FPSem)) !=
APFloat::cmpLessThan) || Fabs.isZero()))
// TODO: Propagate FMF.
return new FCmpInst(Pred, X, ConstantFP::get(C->getContext(), F));
}
}
if (I.getType()->isVectorTy())