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[X86] commuteSelect - update to use SDPatternMatch. NFC. #146868

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Merged
merged 1 commit into from
Jul 3, 2025
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[X86] commuteSelect - update to use SDPatternMatch. NFC. #146868

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27 changes: 11 additions & 16 deletions llvm/lib/Target/X86/X86ISelLowering.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -47568,31 +47568,26 @@ static SDValue combineLogicBlendIntoConditionalNegate(

static SDValue commuteSelect(SDNode *N, SelectionDAG &DAG, const SDLoc &DL,
const X86Subtarget &Subtarget) {
using namespace SDPatternMatch;
if (!Subtarget.hasAVX512())
return SDValue();
if (N->getOpcode() != ISD::VSELECT)
return SDValue();

SDValue Cond = N->getOperand(0);
SDValue LHS = N->getOperand(1);
SDValue RHS = N->getOperand(2);

if (canCombineAsMaskOperation(LHS, Subtarget))
return SDValue();

if (!canCombineAsMaskOperation(RHS, Subtarget))
ISD::CondCode CC;
SDValue Cond, X, Y, LHS, RHS;
if (!sd_match(N, m_VSelect(m_AllOf(m_Value(Cond),
m_OneUse(m_SetCC(m_Value(X), m_Value(Y),
m_CondCode(CC)))),
m_Value(LHS), m_Value(RHS))))
return SDValue();

if (Cond.getOpcode() != ISD::SETCC || !Cond.hasOneUse())
if (canCombineAsMaskOperation(LHS, Subtarget) ||
!canCombineAsMaskOperation(RHS, Subtarget))
return SDValue();

// Commute LHS and RHS to create opportunity to select mask instruction.
// (vselect M, L, R) -> (vselect ~M, R, L)
ISD::CondCode NewCC =
ISD::getSetCCInverse(cast<CondCodeSDNode>(Cond.getOperand(2))->get(),
Cond.getOperand(0).getValueType());
Cond = DAG.getSetCC(SDLoc(Cond), Cond.getValueType(), Cond.getOperand(0),
Cond.getOperand(1), NewCC);
ISD::CondCode NewCC = ISD::getSetCCInverse(CC, X.getValueType());
Cond = DAG.getSetCC(SDLoc(Cond), Cond.getValueType(), X, Y, NewCC);
return DAG.getSelect(DL, LHS.getValueType(), Cond, RHS, LHS);
}

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