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[M68k] Fix reverse BTST condition causing opposite failure/success logic #153086

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Merged
merged 3 commits into from
Aug 20, 2025
Merged

[M68k] Fix reverse BTST condition causing opposite failure/success logic #153086

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6e5bffb
[M68k] Fix backwards BTST condition
dansalvato Aug 11, 2025
38b12ec
fixup! [M68k] Fix backwards BTST condition
dansalvato Aug 20, 2025
0182a21
fixup! [M68k] Fix backwards BTST condition
dansalvato Aug 20, 2025
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4 changes: 2 additions & 2 deletions llvm/lib/Target/M68k/M68kISelLowering.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1667,8 +1667,8 @@ static SDValue getBitTestCondition(SDValue Src, SDValue BitNo, ISD::CondCode CC,

SDValue BTST = DAG.getNode(M68kISD::BTST, DL, MVT::i32, Src, BitNo);

// NOTE BTST sets CCR.Z flag
M68k::CondCode Cond = CC == ISD::SETEQ ? M68k::COND_NE : M68k::COND_EQ;
// NOTE BTST sets CCR.Z flag if bit is 0, same as AND with bitmask
M68k::CondCode Cond = CC == ISD::SETEQ ? M68k::COND_EQ : M68k::COND_NE;
return DAG.getNode(M68kISD::SETCC, DL, MVT::i8,
DAG.getConstant(Cond, DL, MVT::i8), BTST);
}
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