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Differential D143256 Diff 495447 llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp

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llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp

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Show First 20 Lines • Show All 7,971 Lines • ▼ Show 20 Lines if (!Node->getFlags().hasNoNaNs()) {
// Insert canonicalizes if it's possible we need to quiet to get correct // Insert canonicalizes if it's possible we need to quiet to get correct
// sNaN behavior. // sNaN behavior.
if (!DAG.isKnownNeverSNaN(Quiet0)) { if (!DAG.isKnownNeverSNaN(Quiet0)) {
Quiet0 = DAG.getNode(ISD::FCANONICALIZE, dl, VT, Quiet0, Quiet0 = DAG.getNode(ISD::FCANONICALIZE, dl, VT, Quiet0,
Node->getFlags()); Node->getFlags());
} }
if (!DAG.isKnownNeverSNaN(Quiet1)) { if (!DAG.isKnownNeverSNaN(Quiet1)) {
Quiet1 = DAG.getNode(ISD::FCANONICALIZE, dl, VT, Quiet1, Quiet1 = DAG.getNode(ISD::FCANONICALIZE, dl, VT, Quiet1,
Node->getFlags()); Node->getFlags());
spatelUnsubmitted
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Is this different than

auto *C = isConstOrConstSplatFP(N));
return C && C->isZero();
spatel: Is this different than auto *C = isConstOrConstSplatFP(N)); return C && C->isZero();
spatelUnsubmitted
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Oops - invert that isZero() result (we're looking for non-zero constant).

spatel: Oops - invert that isZero() result (we're looking for non-zero constant).
samparkerAuthorUnsubmitted
Done
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For splats, I think your suggestion would work, and that's what I originally tried to do... but it doesn't work for the BUILD_VECTOR case, where we need to check if any element is a zero.

samparker: For splats, I think your suggestion would work, and that's what I originally tried to do... but…
spatelUnsubmitted
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Ah, right. It looks like we do have the basic call already:
SelectionDAG::isKnownNeverZeroFloat().
...and it has a TODO comment about handling a vector constant, so just append that part there?

spatel: Ah, right. It looks like we do have the basic call already: SelectionDAG::isKnownNeverZeroFloat…
samparkerAuthorUnsubmitted
Done
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Nice, will do.

samparker: Nice, will do.
} }
} }
return DAG.getNode(NewOp, dl, VT, Quiet0, Quiet1, Node->getFlags()); return DAG.getNode(NewOp, dl, VT, Quiet0, Quiet1, Node->getFlags());
} }
// If the target has FMINIMUM/FMAXIMUM but not FMINNUM/FMAXNUM use that // If the target has FMINIMUM/FMAXIMUM but not FMINNUM/FMAXNUM use that
// instead if there are no NaNs. // instead if there are no NaNs and there can't be an incompatiable zero
if (Node->getFlags().hasNoNaNs()) { // compare: at least one operand isn't +/-0, or there are no signed-zeros.
if (Node->getFlags().hasNoNaNs() &&
(Node->getFlags().hasNoSignedZeros() ||
DAG.isKnownNeverZeroFloat(Node->getOperand(0)) ||
DAG.isKnownNeverZeroFloat(Node->getOperand(1)))) {
unsigned IEEE2018Op = unsigned IEEE2018Op =
Node->getOpcode() == ISD::FMINNUM ? ISD::FMINIMUM : ISD::FMAXIMUM; Node->getOpcode() == ISD::FMINNUM ? ISD::FMINIMUM : ISD::FMAXIMUM;
spatelUnsubmitted
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Could we also check hasNoSignedZeros() and allow this?

spatel: Could we also check hasNoSignedZeros() and allow this?
if (isOperationLegalOrCustom(IEEE2018Op, VT)) { if (isOperationLegalOrCustom(IEEE2018Op, VT))
return DAG.getNode(IEEE2018Op, dl, VT, Node->getOperand(0), return DAG.getNode(IEEE2018Op, dl, VT, Node->getOperand(0),
Node->getOperand(1), Node->getFlags()); Node->getOperand(1), Node->getFlags());
} }
}
if (SDValue SelCC = createSelectForFMINNUM_FMAXNUM(Node, DAG)) if (SDValue SelCC = createSelectForFMINNUM_FMAXNUM(Node, DAG))
return SelCC; return SelCC;
return SDValue(); return SDValue();
} }
SDValue TargetLowering::expandIS_FPCLASS(EVT ResultVT, SDValue Op, SDValue TargetLowering::expandIS_FPCLASS(EVT ResultVT, SDValue Op,
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