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[DAGCombiner] clean up comments; NFC 

llvm-svn: 334312
This commit is contained in:
Sanjay Patel 2018-06-08 18:00:46 +00:00
parent 03f4f04b91
commit 498564e6fb
1 changed files with 5 additions and 8 deletions
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13
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
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@ -10507,7 +10507,7 @@ SDValue DAGCombiner::visitFMUL(SDNode *N) {
if (N1CFP && N1CFP->isZero())
return N1;
// fold (fmul (fmul x, c1), c2) -> (fmul x, (fmul c1, c2))
// fmul (fmul X, C1), X2 -> fmul X, C1 * C2
if (N0.getOpcode() == ISD::FMUL) {
// Fold scalars or any vector constants (not just splats).
// This fold is done in general by InstCombine, but extra fmul insts
@ -10531,13 +10531,10 @@ SDValue DAGCombiner::visitFMUL(SDNode *N) {
}
}
// fold (fmul (fadd x, x), c) -> (fmul x, (fmul 2.0, c))
// Undo the fmul 2.0, x -> fadd x, x transformation, since if it occurs
// during an early run of DAGCombiner can prevent folding with fmuls
// inserted during lowering.
if (N0.getOpcode() == ISD::FADD &&
(N0.getOperand(0) == N0.getOperand(1)) &&
N0.hasOneUse()) {
// Match a special-case: we convert X * 2.0 into fadd.
// fmul (fadd X, X), C -> fmul X, 2.0 * C
if (N0.getOpcode() == ISD::FADD && N0.hasOneUse() &&
N0.getOperand(0) == N0.getOperand(1)) {
const SDValue Two = DAG.getConstantFP(2.0, DL, VT);
SDValue MulConsts = DAG.getNode(ISD::FMUL, DL, VT, Two, N1, Flags);
return DAG.getNode(ISD::FMUL, DL, VT, N0.getOperand(0), MulConsts, Flags);