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[GlobalISel] Fix [SU]SUBO combine #116998

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[GlobalISel] Fix [SU]SUBO combine #116998

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8 changes: 2 additions & 6 deletions llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -7830,9 +7830,7 @@ bool CombinerHelper::matchSuboCarryOut(const MachineInstr &MI,
case ConstantRange::OverflowResult::AlwaysOverflowsHigh: {
MatchInfo = [=](MachineIRBuilder &B) {
B.buildSub(Dst, LHS, RHS);
B.buildConstant(Carry, getICmpTrueVal(getTargetLowering(),
/*isVector=*/CarryTy.isVector(),
/*isFP=*/false));
B.buildConstant(Carry, 1);
};
return true;
}
Expand All @@ -7855,9 +7853,7 @@ bool CombinerHelper::matchSuboCarryOut(const MachineInstr &MI,
case ConstantRange::OverflowResult::AlwaysOverflowsHigh: {
MatchInfo = [=](MachineIRBuilder &B) {
B.buildSub(Dst, LHS, RHS);
B.buildConstant(Carry, getICmpTrueVal(getTargetLowering(),
/*isVector=*/CarryTy.isVector(),
/*isFP=*/false));
B.buildConstant(Carry, 1);
};
return true;
}
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23 changes: 23 additions & 0 deletions llvm/test/CodeGen/AArch64/GlobalISel/combine-overflow.mir
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Expand Up @@ -277,3 +277,26 @@ body: |
$q1 = COPY %o_wide
RET_ReallyLR implicit $w0
...
---
name: usub_may_carry_non_const
body: |
bb.0:
liveins: $w0, $w1
; CHECK-LABEL: name: usub_may_carry_non_const
; CHECK: liveins: $w0, $w1
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: [[COPY:%[0-9]+]]:_(s32) = COPY $w0
; CHECK-NEXT: [[COPY1:%[0-9]+]]:_(s32) = COPY $w0
; CHECK-NEXT: %sub:_(s32), %o:_(s1) = G_USUBO [[COPY]], [[COPY1]]
; CHECK-NEXT: %o_wide:_(s32) = G_ZEXT %o(s1)
; CHECK-NEXT: $w0 = COPY %sub(s32)
; CHECK-NEXT: $w1 = COPY %o_wide(s32)
; CHECK-NEXT: RET_ReallyLR implicit $w0
%0:_(s32) = COPY $w0
%1:_(s32) = COPY $w0
%sub:_(s32), %o:_(s1) = G_USUBO %0, %1
%o_wide:_(s32) = G_ZEXT %o(s1)
$w0 = COPY %sub(s32)
$w1 = COPY %o_wide
RET_ReallyLR implicit $w0
...
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