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[InstCombine] Fold (add (add A, 1), (sext (icmp ne A, 0))) to call umax(A, 1) (#122491)
Transform (add (add A, 1), (sext (icmp ne A, 0))) into call umax(A, 1). Fixes #121853. Alive2: https://alive2.llvm.org/ce/z/TweTan
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‎llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp

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@@ -1775,6 +1775,15 @@ Instruction *InstCombinerImpl::visitAdd(BinaryOperator &I) {
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}
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}
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// (add (add A, 1), (sext (icmp ne A, 0))) => call umax(A, 1)
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if (match(LHS, m_Add(m_Value(A), m_One())) &&
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match(RHS, m_OneUse(m_SExt(m_OneUse(m_SpecificICmp(
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ICmpInst::ICMP_NE, m_Specific(A), m_ZeroInt())))))) {
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Value *OneConst = ConstantInt::get(A->getType(), 1);
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Value *UMax = Builder.CreateBinaryIntrinsic(Intrinsic::umax, A, OneConst);
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return replaceInstUsesWith(I, UMax);
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}
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if (Instruction *Ashr = foldAddToAshr(I))
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return Ashr;
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‎llvm/test/Transforms/InstCombine/add-sext-icmp.ll

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; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
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; RUN: opt -S -passes=instcombine < %s | FileCheck %s
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; The pattern:
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; add(add A, 1), (sext(icmp ne A, 0))
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; is transformed into:
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; umax(A, 1)
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define i32 @add_sext_icmp(i32 %A) {
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; CHECK-LABEL: define i32 @add_sext_icmp(
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; CHECK-SAME: i32 [[A:%.*]]) {
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; CHECK-NEXT: [[ADD2:%.*]] = call i32 @llvm.umax.i32(i32 [[A]], i32 1)
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; CHECK-NEXT: ret i32 [[ADD2]]
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;
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%add1 = add i32 %A, 1
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%icmp = icmp ne i32 %A, 0
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%sext = sext i1 %icmp to i32
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%add2 = add i32 %add1, %sext
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ret i32 %add2
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}
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define i32 @add_sext_icmp_commutative(i32 %A) {
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; CHECK-LABEL: define i32 @add_sext_icmp_commutative(
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; CHECK-SAME: i32 [[A:%.*]]) {
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; CHECK-NEXT: [[ADD2:%.*]] = call i32 @llvm.umax.i32(i32 [[A]], i32 1)
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; CHECK-NEXT: ret i32 [[ADD2]]
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;
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%add1 = add i32 %A, 1
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%icmp = icmp ne i32 %A, 0
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%sext = sext i1 %icmp to i32
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%add2 = add i32 %sext, %add1
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ret i32 %add2
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}
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; Negative test
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define i32 @add_sext_icmp_negative_constant(i32 %A) {
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; CHECK-LABEL: define i32 @add_sext_icmp_negative_constant(
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; CHECK-SAME: i32 [[A:%.*]]) {
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; CHECK-NEXT: [[ADD1:%.*]] = add i32 [[A]], 2
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; CHECK-NEXT: [[ICMP:%.*]] = icmp ne i32 [[A]], 0
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; CHECK-NEXT: [[SEXT:%.*]] = sext i1 [[ICMP]] to i32
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; CHECK-NEXT: [[ADD2:%.*]] = add i32 [[ADD1]], [[SEXT]]
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; CHECK-NEXT: ret i32 [[ADD2]]
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;
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%add1 = add i32 %A, 2
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%icmp = icmp ne i32 %A, 0
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%sext = sext i1 %icmp to i32
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%add2 = add i32 %add1, %sext
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ret i32 %add2
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}
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define i32 @add_sext_icmp_negative_pred(i32 %A) {
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; CHECK-LABEL: define i32 @add_sext_icmp_negative_pred(
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; CHECK-SAME: i32 [[A:%.*]]) {
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; CHECK-NEXT: [[ADD1:%.*]] = add i32 [[A]], 1
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; CHECK-NEXT: [[ICMP:%.*]] = icmp eq i32 [[A]], 0
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; CHECK-NEXT: [[SEXT:%.*]] = sext i1 [[ICMP]] to i32
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; CHECK-NEXT: [[ADD2:%.*]] = add i32 [[ADD1]], [[SEXT]]
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; CHECK-NEXT: ret i32 [[ADD2]]
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;
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%add1 = add i32 %A, 1
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%icmp = icmp eq i32 %A, 0
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%sext = sext i1 %icmp to i32
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%add2 = add i32 %add1, %sext
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ret i32 %add2
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}
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; multi-use test
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define i32 @add_sext_icmp_multi_use_add2(i32 %A) {
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; CHECK-LABEL: define i32 @add_sext_icmp_multi_use_add2(
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; CHECK-SAME: i32 [[A:%.*]]) {
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; CHECK-NEXT: [[ADD2:%.*]] = call i32 @llvm.umax.i32(i32 [[A]], i32 1)
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; CHECK-NEXT: call void @use(i32 [[ADD2]])
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; CHECK-NEXT: ret i32 [[ADD2]]
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;
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%add1 = add i32 %A, 1
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%icmp = icmp ne i32 %A, 0
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%sext = sext i1 %icmp to i32
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%add2 = add i32 %add1, %sext
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call void @use(i32 %add2)
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ret i32 %add2
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}
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define i32 @add_sext_icmp_multi_use_sext(i32 %A) {
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; CHECK-LABEL: define i32 @add_sext_icmp_multi_use_sext(
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; CHECK-SAME: i32 [[A:%.*]]) {
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; CHECK-NEXT: [[ADD1:%.*]] = add i32 [[A]], 1
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; CHECK-NEXT: [[ICMP:%.*]] = icmp ne i32 [[A]], 0
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; CHECK-NEXT: [[SEXT:%.*]] = sext i1 [[ICMP]] to i32
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; CHECK-NEXT: call void @use(i32 [[SEXT]])
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; CHECK-NEXT: [[ADD2:%.*]] = add i32 [[ADD1]], [[SEXT]]
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; CHECK-NEXT: ret i32 [[ADD2]]
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;
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%add1 = add i32 %A, 1
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%icmp = icmp ne i32 %A, 0
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%sext = sext i1 %icmp to i32
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call void @use(i32 %sext)
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%add2 = add i32 %add1, %sext
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ret i32 %add2
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}
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define i32 @add_sext_icmp_multi_use_icmp(i32 %A) {
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; CHECK-LABEL: define i32 @add_sext_icmp_multi_use_icmp(
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; CHECK-SAME: i32 [[A:%.*]]) {
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; CHECK-NEXT: [[ADD1:%.*]] = add i32 [[A]], 1
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; CHECK-NEXT: [[ICMP:%.*]] = icmp ne i32 [[A]], 0
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; CHECK-NEXT: call void @use(i1 [[ICMP]])
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; CHECK-NEXT: [[SEXT:%.*]] = sext i1 [[ICMP]] to i32
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; CHECK-NEXT: [[ADD2:%.*]] = add i32 [[ADD1]], [[SEXT]]
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; CHECK-NEXT: ret i32 [[ADD2]]
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;
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%add1 = add i32 %A, 1
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%icmp = icmp ne i32 %A, 0
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call void @use(i1 %icmp)
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%sext = sext i1 %icmp to i32
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%add2 = add i32 %add1, %sext
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ret i32 %add2
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}
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define i32 @add_sext_icmp_multi_use_add1(i32 %A) {
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; CHECK-LABEL: define i32 @add_sext_icmp_multi_use_add1(
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; CHECK-SAME: i32 [[A:%.*]]) {
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; CHECK-NEXT: [[ADD1:%.*]] = add i32 [[A]], 1
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; CHECK-NEXT: call void @use(i32 [[ADD1]])
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; CHECK-NEXT: [[ADD2:%.*]] = call i32 @llvm.umax.i32(i32 [[A]], i32 1)
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; CHECK-NEXT: ret i32 [[ADD2]]
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;
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%add1 = add i32 %A, 1
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call void @use(i32 %add1)
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%icmp = icmp ne i32 %A, 0
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%sext = sext i1 %icmp to i32
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%add2 = add i32 %add1, %sext
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ret i32 %add2
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}
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declare void @use(i32)
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