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[RISCV] Add freeze when expanding mul by constant to two or more uses #89290

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Merged
merged 1 commit into from
Apr 22, 2024
Merged

[RISCV] Add freeze when expanding mul by constant to two or more uses #89290

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23 changes: 12 additions & 11 deletions llvm/lib/Target/RISCV/RISCVISelLowering.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -13430,10 +13430,11 @@ static SDValue expandMul(SDNode *N, SelectionDAG &DAG,
if (ScaleShift >= 1 && ScaleShift < 4) {
unsigned ShiftAmt = Log2_64((MulAmt & (MulAmt - 1)));
SDLoc DL(N);
SDValue Shift1 = DAG.getNode(ISD::SHL, DL, VT, N->getOperand(0),
DAG.getConstant(ShiftAmt, DL, VT));
SDValue Shift2 = DAG.getNode(ISD::SHL, DL, VT, N->getOperand(0),
DAG.getConstant(ScaleShift, DL, VT));
SDValue X = DAG.getFreeze(N->getOperand(0));
SDValue Shift1 =
DAG.getNode(ISD::SHL, DL, VT, X, DAG.getConstant(ShiftAmt, DL, VT));
SDValue Shift2 =
DAG.getNode(ISD::SHL, DL, VT, X, DAG.getConstant(ScaleShift, DL, VT));
return DAG.getNode(ISD::ADD, DL, VT, Shift1, Shift2);
}
}
Expand Down Expand Up @@ -13464,13 +13465,13 @@ static SDValue expandMul(SDNode *N, SelectionDAG &DAG,
if (ScaleShift >= 1 && ScaleShift < 4) {
unsigned ShiftAmt = Log2_64(((MulAmt - 1) & (MulAmt - 2)));
SDLoc DL(N);
SDValue Shift1 = DAG.getNode(ISD::SHL, DL, VT, N->getOperand(0),
DAG.getConstant(ShiftAmt, DL, VT));
SDValue Shift2 = DAG.getNode(ISD::SHL, DL, VT, N->getOperand(0),
DAG.getConstant(ScaleShift, DL, VT));
return DAG.getNode(
ISD::ADD, DL, VT, Shift1,
DAG.getNode(ISD::ADD, DL, VT, Shift2, N->getOperand(0)));
SDValue X = DAG.getFreeze(N->getOperand(0));
SDValue Shift1 =
DAG.getNode(ISD::SHL, DL, VT, X, DAG.getConstant(ShiftAmt, DL, VT));
SDValue Shift2 =
DAG.getNode(ISD::SHL, DL, VT, X, DAG.getConstant(ScaleShift, DL, VT));
return DAG.getNode(ISD::ADD, DL, VT, Shift1,
DAG.getNode(ISD::ADD, DL, VT, Shift2, X));
}
}

Expand Down