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[InstCombine] Drop samesign in foldLogOpOfMaskedICmps #125829

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Merged
merged 4 commits into from
Feb 7, 2025
Merged

[InstCombine] Drop samesign in foldLogOpOfMaskedICmps #125829

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feed257
[InstCombine] Add pre-commit tests. NFC.
dtcxzyw Feb 5, 2025
c9dc295
[InstCombine] Drop samesign in `foldLogOpOfMaskedICmps`
dtcxzyw Feb 5, 2025
6c08d52
[InstCombine] Handle non-icmp
dtcxzyw Feb 6, 2025
3d4f9bf
[InstCombine] Address review comments. NFC.
dtcxzyw Feb 6, 2025
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7 changes: 6 additions & 1 deletion llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -610,8 +610,13 @@ static Value *foldLogOpOfMaskedICmps(Value *LHS, Value *RHS, bool IsAnd,
APInt NewMask = *ConstB & *ConstD;
if (NewMask == *ConstB)
return LHS;
if (NewMask == *ConstD)
if (NewMask == *ConstD) {
if (IsLogical) {
if (auto *RHSI = dyn_cast<Instruction>(RHS))
RHSI->dropPoisonGeneratingFlags();
}
return RHS;
}
}

if (Mask & AMask_NotAllOnes) {
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23 changes: 23 additions & 0 deletions llvm/test/Transforms/InstCombine/sign-test-and-or.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -349,6 +349,29 @@ define i1 @test9_logical(i32 %a) {
ret i1 %or.cond
}

define i1 @test9_logical_samesign(i32 %a) {
; CHECK-LABEL: @test9_logical_samesign(
; CHECK-NEXT: [[CMP2:%.*]] = icmp sgt i32 [[A:%.*]], -1
; CHECK-NEXT: ret i1 [[CMP2]]
;
%masked = and i32 %a, -1073741825
%cmp1 = icmp eq i32 %masked, 0
%cmp2 = icmp samesign sgt i32 %a, -1
%or.cond = select i1 %cmp1, i1 true, i1 %cmp2
ret i1 %or.cond
}

define i1 @test_logical_or_icmp_icmp_samesign(i32 %a) {
; CHECK-LABEL: @test_logical_or_icmp_icmp_samesign(
; CHECK-NEXT: [[CMP2:%.*]] = icmp sgt i32 [[A:%.*]], -1
; CHECK-NEXT: ret i1 [[CMP2]]
;
%cmp1 = icmp eq i32 %a, 0
%cmp2 = icmp samesign sgt i32 %a, -1
%or = select i1 %cmp1, i1 true, i1 %cmp2
ret i1 %or
}

define i1 @test10(i32 %a) {
; CHECK-LABEL: @test10(
; CHECK-NEXT: [[OR_COND:%.*]] = icmp ult i32 [[A:%.*]], 2
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