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[RISCV] Don't transfer (select c, t, f) to Zicond when optimizing for size #163501

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[RISCV] Don't transfer (select c, t, f) to Zicond when optimizing for size #163501

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[RISCV] Pre-commit
tclin914 Oct 15, 2025
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[RISCV] Don't transfer (select c, t, f) to Zicond when optimizing for…
tclin914 Oct 15, 2025
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tclin914 Oct 16, 2025
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6 changes: 4 additions & 2 deletions llvm/lib/Target/RISCV/RISCVISelLowering.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -9458,8 +9458,10 @@ SDValue RISCVTargetLowering::lowerSELECT(SDValue Op, SelectionDAG &DAG) const {
}

// (select c, t, f) -> (or (czero_eqz t, c), (czero_nez f, c))
// Unless we have the short forward branch optimization.
if (!Subtarget.hasConditionalMoveFusion())
// Unless we have the short forward branch optimization or CondV has one use
// when optimizaing for size.
if (!Subtarget.hasConditionalMoveFusion() &&
(!DAG.shouldOptForSize() || CondV.hasOneUse()))
return DAG.getNode(
ISD::OR, DL, VT,
DAG.getNode(RISCVISD::CZERO_EQZ, DL, VT, TrueV, CondV),
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