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DAG: Preserve flags when expanding fminimum/fmaximum #93550

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Merged
merged 1 commit into from
May 29, 2024
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DAG: Preserve flags when expanding fminimum/fmaximum #93550

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4 changes: 2 additions & 2 deletions llvm/include/llvm/CodeGen/SelectionDAG.h
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Original file line number Diff line number Diff line change
Expand Up @@ -1241,11 +1241,11 @@ class SelectionDAG {
/// Helper function to make it easier to build Select's if you just have
/// operands and don't want to check for vector.
SDValue getSelect(const SDLoc &DL, EVT VT, SDValue Cond, SDValue LHS,
SDValue RHS) {
SDValue RHS, SDNodeFlags Flags = SDNodeFlags()) {
assert(LHS.getValueType() == VT && RHS.getValueType() == VT &&
"Cannot use select on differing types");
auto Opcode = Cond.getValueType().isVector() ? ISD::VSELECT : ISD::SELECT;
return getNode(Opcode, DL, VT, Cond, LHS, RHS);
return getNode(Opcode, DL, VT, Cond, LHS, RHS, Flags);
}

/// Helper function to make it easier to build SelectCC's if you just have an
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15 changes: 8 additions & 7 deletions llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -8428,6 +8428,7 @@ SDValue TargetLowering::expandFMINIMUM_FMAXIMUM(SDNode *N,
EVT VT = N->getValueType(0);
EVT CCVT = getSetCCResultType(DAG.getDataLayout(), *DAG.getContext(), VT);
bool IsMax = Opc == ISD::FMAXIMUM;
SDNodeFlags Flags = N->getFlags();

if (VT.isVector() &&
isOperationLegalOrCustomOrPromote(Opc, VT.getScalarType()))
Expand All @@ -8444,15 +8445,15 @@ SDValue TargetLowering::expandFMINIMUM_FMAXIMUM(SDNode *N,
bool MinMaxMustRespectOrderedZero = false;

if (isOperationLegalOrCustom(CompOpcIeee, VT)) {
MinMax = DAG.getNode(CompOpcIeee, DL, VT, LHS, RHS);
MinMax = DAG.getNode(CompOpcIeee, DL, VT, LHS, RHS, Flags);
MinMaxMustRespectOrderedZero = true;
} else if (isOperationLegalOrCustom(CompOpc, VT)) {
MinMax = DAG.getNode(CompOpc, DL, VT, LHS, RHS);
MinMax = DAG.getNode(CompOpc, DL, VT, LHS, RHS, Flags);
} else {
// NaN (if exists) will be propagated later, so orderness doesn't matter.
SDValue Compare =
DAG.getSetCC(DL, CCVT, LHS, RHS, IsMax ? ISD::SETGT : ISD::SETLT);
MinMax = DAG.getSelect(DL, VT, Compare, LHS, RHS);
MinMax = DAG.getSelect(DL, VT, Compare, LHS, RHS, Flags);
}

// Propagate any NaN of both operands
Expand All @@ -8461,7 +8462,7 @@ SDValue TargetLowering::expandFMINIMUM_FMAXIMUM(SDNode *N,
ConstantFP *FPNaN = ConstantFP::get(
*DAG.getContext(), APFloat::getNaN(DAG.EVTToAPFloatSemantics(VT)));
MinMax = DAG.getSelect(DL, VT, DAG.getSetCC(DL, CCVT, LHS, RHS, ISD::SETUO),
DAG.getConstantFP(*FPNaN, DL, VT), MinMax);
DAG.getConstantFP(*FPNaN, DL, VT), MinMax, Flags);
}

// fminimum/fmaximum requires -0.0 less than +0.0
Expand All @@ -8473,11 +8474,11 @@ SDValue TargetLowering::expandFMINIMUM_FMAXIMUM(SDNode *N,
DAG.getTargetConstant(IsMax ? fcPosZero : fcNegZero, DL, MVT::i32);
SDValue LCmp = DAG.getSelect(
DL, VT, DAG.getNode(ISD::IS_FPCLASS, DL, CCVT, LHS, TestZero), LHS,
MinMax);
MinMax, Flags);
SDValue RCmp = DAG.getSelect(
DL, VT, DAG.getNode(ISD::IS_FPCLASS, DL, CCVT, RHS, TestZero), RHS,
LCmp);
MinMax = DAG.getSelect(DL, VT, IsZero, RCmp, MinMax);
LCmp, Flags);
MinMax = DAG.getSelect(DL, VT, IsZero, RCmp, MinMax, Flags);
}

return MinMax;
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