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[InstCombine] Relax the one-use constraints for icmp pred (binop X, Z), (binop Y, Z) #76384

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Merged
merged 2 commits into from
Jan 7, 2024
Merged

[InstCombine] Relax the one-use constraints for icmp pred (binop X, Z), (binop Y, Z) #76384

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7177f67
[InstCombine] Add pre-commit tests. NFC.
dtcxzyw Dec 26, 2023
aa88812
[InstCombine] Relax the one-use constraints for `icmp pred (binop X, …
dtcxzyw Dec 26, 2023
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5 changes: 3 additions & 2 deletions llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -4911,8 +4911,9 @@ Instruction *InstCombinerImpl::foldICmpBinOp(ICmpInst &I,
}
}

if (BO0 && BO1 && BO0->getOpcode() == BO1->getOpcode() && BO0->hasOneUse() &&
BO1->hasOneUse() && BO0->getOperand(1) == BO1->getOperand(1)) {
if (BO0 && BO1 && BO0->getOpcode() == BO1->getOpcode() &&
(BO0->hasOneUse() || BO1->hasOneUse()) &&
BO0->getOperand(1) == BO1->getOperand(1)) {
switch (BO0->getOpcode()) {
default:
break;
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45 changes: 45 additions & 0 deletions llvm/test/Transforms/InstCombine/icmp.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -815,6 +815,51 @@ define i1 @test46(i32 %X, i32 %Y, i32 %Z) {
ret i1 %C
}

define i1 @test46_multiuse1(i32 %X, i32 %Y, i32 %Z) {
; CHECK-LABEL: @test46_multiuse1(
; CHECK-NEXT: [[A:%.*]] = ashr exact i32 [[X:%.*]], [[Z:%.*]]
; CHECK-NEXT: call void @use_i32(i32 [[A]])
; CHECK-NEXT: [[C:%.*]] = icmp ult i32 [[X]], [[Y:%.*]]
; CHECK-NEXT: ret i1 [[C]]
;
%A = ashr exact i32 %X, %Z
call void @use_i32(i32 %A)
%B = ashr exact i32 %Y, %Z
%C = icmp ult i32 %A, %B
ret i1 %C
}

define i1 @test46_multiuse2(i32 %X, i32 %Y, i32 %Z) {
; CHECK-LABEL: @test46_multiuse2(
; CHECK-NEXT: [[B:%.*]] = ashr exact i32 [[Y:%.*]], [[Z:%.*]]
; CHECK-NEXT: call void @use_i32(i32 [[B]])
; CHECK-NEXT: [[C:%.*]] = icmp ult i32 [[X:%.*]], [[Y]]
; CHECK-NEXT: ret i1 [[C]]
;
%A = ashr exact i32 %X, %Z
%B = ashr exact i32 %Y, %Z
call void @use_i32(i32 %B)
%C = icmp ult i32 %A, %B
ret i1 %C
}

define i1 @test46_multiuse3(i32 %X, i32 %Y, i32 %Z) {
; CHECK-LABEL: @test46_multiuse3(
; CHECK-NEXT: [[A:%.*]] = ashr exact i32 [[X:%.*]], [[Z:%.*]]
; CHECK-NEXT: call void @use_i32(i32 [[A]])
; CHECK-NEXT: [[B:%.*]] = ashr exact i32 [[Y:%.*]], [[Z]]
; CHECK-NEXT: call void @use_i32(i32 [[B]])
; CHECK-NEXT: [[C:%.*]] = icmp ult i32 [[A]], [[B]]
; CHECK-NEXT: ret i1 [[C]]
;
%A = ashr exact i32 %X, %Z
call void @use_i32(i32 %A)
%B = ashr exact i32 %Y, %Z
call void @use_i32(i32 %B)
%C = icmp ult i32 %A, %B
ret i1 %C
}

; PR9343 #5
define i1 @test47(i32 %X, i32 %Y, i32 %Z) {
; CHECK-LABEL: @test47(
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