[llvm] [InstCombine] fold (A + B - C == B) -> (A == C). (PR #76129)
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llvm-commits at lists.llvm.org
Thu Dec 21 04:18:28 PST 2023
https://github.com/sun-jacobi updated https://github.com/llvm/llvm-project/pull/76129
>From 98c373005e84368758128d051d89f260ecfab65c Mon Sep 17 00:00:00 2001
From: sun-jacobi <sun1011jacobi at gmail.com>
Date: Thu, 21 Dec 2023 14:12:04 +0900
Subject: [PATCH 1/5] [InstCombine] fold (A + B - C == B) -> (A - C == 0)
---
.../InstCombine/InstCombineCompares.cpp | 44 +++++++++++++++++++
.../InstCombine/InstCombineInternal.h | 2 +
2 files changed, 46 insertions(+)
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
index 0ad87eeb4c91a4..ca30e5b6ad779b 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -4547,6 +4547,45 @@ static Instruction *foldICmpXorXX(ICmpInst &I, const SimplifyQuery &Q,
return nullptr;
}
+// extract common factors like ((A + B) - C == B) -> (A - C == 0)
+Value *InstCombinerImpl::foldICmpWithCommonFactors(ICmpInst &Cmp,
+ BinaryOperator *LBO,
+ Value *RHS) {
+ const CmpInst::Predicate Pred = Cmp.getPredicate();
+ if (!ICmpInst::isEquality(Pred))
+ return nullptr;
+
+ SmallVector<BinaryOperator *, 16> WorkList(1, LBO);
+
+ while (!WorkList.empty()) {
+ BinaryOperator *BO = WorkList.pop_back_val();
+
+ Value *A;
+ if (match(BO, m_OneUse(m_c_Add(m_Value(A), m_Specific(RHS))))) {
+ if (BO == LBO)
+ return Builder.CreateICmp(Pred, A,
+ Constant::getNullValue(LBO->getType()));
+ replaceInstUsesWith(*BO, A);
+ eraseInstFromFunction(*BO);
+ return Builder.CreateICmp(Pred, LBO,
+ Constant::getNullValue(LBO->getType()));
+ }
+
+ unsigned Opc = BO->getOpcode();
+ if (Opc == Instruction::Add || Opc == Instruction::Sub) {
+ auto AddNextBO = [&](Value *Op) {
+ if (BinaryOperator *Next = dyn_cast<BinaryOperator>(Op))
+ WorkList.push_back(Next);
+ };
+
+ AddNextBO(BO->getOperand(0));
+ AddNextBO(BO->getOperand(1));
+ }
+ }
+
+ return nullptr;
+}
+
/// Try to fold icmp (binop), X or icmp X, (binop).
/// TODO: A large part of this logic is duplicated in InstSimplify's
/// simplifyICmpWithBinOp(). We should be able to share that and avoid the code
@@ -4565,6 +4604,11 @@ Instruction *InstCombinerImpl::foldICmpBinOp(ICmpInst &I,
if (Instruction *NewICmp = foldICmpXNegX(I, Builder))
return NewICmp;
+ if (BO0) {
+ if (Value *V = foldICmpWithCommonFactors(I, BO0, Op1))
+ return replaceInstUsesWith(I, V);
+ }
+
const CmpInst::Predicate Pred = I.getPredicate();
Value *X;
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineInternal.h b/llvm/lib/Transforms/InstCombine/InstCombineInternal.h
index f86db698ef8f12..54a9dd9942d09c 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineInternal.h
+++ b/llvm/lib/Transforms/InstCombine/InstCombineInternal.h
@@ -632,6 +632,8 @@ class LLVM_LIBRARY_VISIBILITY InstCombinerImpl final
Instruction *foldICmpInstWithConstantNotInt(ICmpInst &Cmp);
Instruction *foldICmpInstWithConstantAllowUndef(ICmpInst &Cmp,
const APInt &C);
+ Value *foldICmpWithCommonFactors(ICmpInst &Cmp, BinaryOperator *LBO,
+ Value *RHS);
Instruction *foldICmpBinOp(ICmpInst &Cmp, const SimplifyQuery &SQ);
Instruction *foldICmpWithMinMaxImpl(Instruction &I, MinMaxIntrinsic *MinMax,
Value *Z, ICmpInst::Predicate Pred);
>From 6b272c60951fa0132dbe9a8866d42ba7b414fee4 Mon Sep 17 00:00:00 2001
From: sun-jacobi <sun1011jacobi at gmail.com>
Date: Thu, 21 Dec 2023 16:29:33 +0900
Subject: [PATCH 2/5] [InstCombine] refactor foldICmpWithCommonFactors
---
.../InstCombine/InstCombineCompares.cpp | 34 +++++++++----------
.../InstCombine/InstCombineInternal.h | 4 +--
2 files changed, 18 insertions(+), 20 deletions(-)
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
index ca30e5b6ad779b..5482b044deadc9 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -4548,34 +4548,32 @@ static Instruction *foldICmpXorXX(ICmpInst &I, const SimplifyQuery &Q,
}
// extract common factors like ((A + B) - C == B) -> (A - C == 0)
-Value *InstCombinerImpl::foldICmpWithCommonFactors(ICmpInst &Cmp,
- BinaryOperator *LBO,
- Value *RHS) {
+Instruction *InstCombinerImpl::foldICmpWithCommonFactors(ICmpInst &Cmp,
+ BinaryOperator *LBO,
+ Value *RHS) {
const CmpInst::Predicate Pred = Cmp.getPredicate();
if (!ICmpInst::isEquality(Pred))
return nullptr;
- SmallVector<BinaryOperator *, 16> WorkList(1, LBO);
+ SmallVector<BinaryOperator *, 16> worklist(1, LBO);
+ Constant *Zero = Constant::getNullValue(LBO->getType());
- while (!WorkList.empty()) {
- BinaryOperator *BO = WorkList.pop_back_val();
+ while (!worklist.empty()) {
+ BinaryOperator *BO = worklist.pop_back_val();
- Value *A;
- if (match(BO, m_OneUse(m_c_Add(m_Value(A), m_Specific(RHS))))) {
- if (BO == LBO)
- return Builder.CreateICmp(Pred, A,
- Constant::getNullValue(LBO->getType()));
- replaceInstUsesWith(*BO, A);
- eraseInstFromFunction(*BO);
- return Builder.CreateICmp(Pred, LBO,
- Constant::getNullValue(LBO->getType()));
+ if (Value * A; match(BO, m_OneUse(m_c_Add(m_Value(A), m_Specific(RHS))))) {
+ if (BO != LBO) {
+ replaceInstUsesWith(*BO, A);
+ eraseInstFromFunction(*BO);
+ }
+ return new ICmpInst(Pred, A, Zero);
}
unsigned Opc = BO->getOpcode();
if (Opc == Instruction::Add || Opc == Instruction::Sub) {
auto AddNextBO = [&](Value *Op) {
if (BinaryOperator *Next = dyn_cast<BinaryOperator>(Op))
- WorkList.push_back(Next);
+ worklist.push_back(Next);
};
AddNextBO(BO->getOperand(0));
@@ -4605,8 +4603,8 @@ Instruction *InstCombinerImpl::foldICmpBinOp(ICmpInst &I,
return NewICmp;
if (BO0) {
- if (Value *V = foldICmpWithCommonFactors(I, BO0, Op1))
- return replaceInstUsesWith(I, V);
+ if (Instruction *NewICmp = foldICmpWithCommonFactors(I, BO0, Op1))
+ return NewICmp;
}
const CmpInst::Predicate Pred = I.getPredicate();
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineInternal.h b/llvm/lib/Transforms/InstCombine/InstCombineInternal.h
index 54a9dd9942d09c..9081373c0157d6 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineInternal.h
+++ b/llvm/lib/Transforms/InstCombine/InstCombineInternal.h
@@ -632,8 +632,8 @@ class LLVM_LIBRARY_VISIBILITY InstCombinerImpl final
Instruction *foldICmpInstWithConstantNotInt(ICmpInst &Cmp);
Instruction *foldICmpInstWithConstantAllowUndef(ICmpInst &Cmp,
const APInt &C);
- Value *foldICmpWithCommonFactors(ICmpInst &Cmp, BinaryOperator *LBO,
- Value *RHS);
+ Instruction *foldICmpWithCommonFactors(ICmpInst &Cmp, BinaryOperator *LBO,
+ Value *RHS);
Instruction *foldICmpBinOp(ICmpInst &Cmp, const SimplifyQuery &SQ);
Instruction *foldICmpWithMinMaxImpl(Instruction &I, MinMaxIntrinsic *MinMax,
Value *Z, ICmpInst::Predicate Pred);
>From e3999c39c007cf5c2f8125512aab4e479a8256a1 Mon Sep 17 00:00:00 2001
From: sun-jacobi <sun1011jacobi at gmail.com>
Date: Thu, 21 Dec 2023 16:50:15 +0900
Subject: [PATCH 3/5] [InstCombine] fix bugs in foldICmpWithCommonFactors
---
llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
index 5482b044deadc9..399af8d1133f08 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -4566,7 +4566,7 @@ Instruction *InstCombinerImpl::foldICmpWithCommonFactors(ICmpInst &Cmp,
replaceInstUsesWith(*BO, A);
eraseInstFromFunction(*BO);
}
- return new ICmpInst(Pred, A, Zero);
+ return new ICmpInst(Pred, LBO, Zero);
}
unsigned Opc = BO->getOpcode();
>From 88b44ceef7813f295a1ac071a4dab899bb5d452f Mon Sep 17 00:00:00 2001
From: sun-jacobi <sun1011jacobi at gmail.com>
Date: Thu, 21 Dec 2023 16:51:04 +0900
Subject: [PATCH 4/5] [InstCombine] add icmp-eq-common-factor.ll test
---
.../InstCombine/icmp-eq-common-factor.ll | 121 ++++++++++++++++++
1 file changed, 121 insertions(+)
create mode 100644 llvm/test/Transforms/InstCombine/icmp-eq-common-factor.ll
diff --git a/llvm/test/Transforms/InstCombine/icmp-eq-common-factor.ll b/llvm/test/Transforms/InstCombine/icmp-eq-common-factor.ll
new file mode 100644
index 00000000000000..e28c0910c9cae2
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/icmp-eq-common-factor.ll
@@ -0,0 +1,121 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 4
+; RUN: opt -passes=instcombine -S < %s | FileCheck %s
+
+; A + B - C == B
+define i1 @icmp_common_add_sub(i32 %a, i32 %b, i32 %c){
+; CHECK-LABEL: define i1 @icmp_common_add_sub(
+; CHECK-SAME: i32 [[A:%.*]], i32 [[B:%.*]], i32 [[C:%.*]]) {
+; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[A]], [[C]]
+; CHECK-NEXT: ret i1 [[CMP]]
+;
+ %add = add i32 %a, %b
+ %sub = sub i32 %add, %c
+ %cmp = icmp eq i32 %sub, %b
+ ret i1 %cmp
+}
+
+; A + B - C == B
+define i1 @icmp_common_add_sub_ne(i32 %a, i32 %b, i32 %c){
+; CHECK-LABEL: define i1 @icmp_common_add_sub_ne(
+; CHECK-SAME: i32 [[A:%.*]], i32 [[B:%.*]], i32 [[C:%.*]]) {
+; CHECK-NEXT: [[CMP:%.*]] = icmp ne i32 [[A]], [[C]]
+; CHECK-NEXT: ret i1 [[CMP]]
+;
+ %add = add i32 %a, %b
+ %sub = sub i32 %add, %c
+ %cmp = icmp ne i32 %sub, %b
+ ret i1 %cmp
+}
+
+; A * B - C == B
+define i1 @icmp_common_mul_sub(i32 %a, i32 %b, i32 %c){
+; CHECK-LABEL: define i1 @icmp_common_mul_sub(
+; CHECK-SAME: i32 [[A:%.*]], i32 [[B:%.*]], i32 [[C:%.*]]) {
+; CHECK-NEXT: [[MUL:%.*]] = mul i32 [[A]], [[B]]
+; CHECK-NEXT: [[SUB:%.*]] = sub i32 [[MUL]], [[C]]
+; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[SUB]], [[B]]
+; CHECK-NEXT: ret i1 [[CMP]]
+;
+ %mul = mul i32 %a, %b
+ %sub = sub i32 %mul, %c
+ %cmp = icmp eq i32 %sub, %b
+ ret i1 %cmp
+}
+
+; A + B + C == B
+define i1 @icmp_common_add_add(i32 %a, i32 %b, i32 %c){
+; CHECK-LABEL: define i1 @icmp_common_add_add(
+; CHECK-SAME: i32 [[A:%.*]], i32 [[B:%.*]], i32 [[C:%.*]]) {
+; CHECK-NEXT: [[ADD2:%.*]] = sub i32 0, [[C]]
+; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[ADD2]], [[A]]
+; CHECK-NEXT: ret i1 [[CMP]]
+;
+ %add1 = add i32 %a, %b
+ %add2 = add i32 %add1, %c
+ %cmp = icmp eq i32 %add2, %b
+ ret i1 %cmp
+}
+
+; A + B + C + D == B
+define i1 @icmp_common_add_add_add(i32 %a, i32 %b, i32 %c, i32 %d){
+; CHECK-LABEL: define i1 @icmp_common_add_add_add(
+; CHECK-SAME: i32 [[A:%.*]], i32 [[B:%.*]], i32 [[C:%.*]], i32 [[D:%.*]]) {
+; CHECK-NEXT: [[ADD2:%.*]] = add i32 [[A]], [[C]]
+; CHECK-NEXT: [[ADD3:%.*]] = sub i32 0, [[D]]
+; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[ADD2]], [[ADD3]]
+; CHECK-NEXT: ret i1 [[CMP]]
+;
+ %add1 = add i32 %a, %b
+ %add2 = add i32 %add1, %c
+ %add3 = add i32 %add2, %d
+ %cmp = icmp eq i32 %add3, %b
+ ret i1 %cmp
+}
+
+; A + B + C + D == C
+define i1 @icmp_common_add_add_add_2(i32 %a, i32 %b, i32 %c, i32 %d){
+; CHECK-LABEL: define i1 @icmp_common_add_add_add_2(
+; CHECK-SAME: i32 [[A:%.*]], i32 [[B:%.*]], i32 [[C:%.*]], i32 [[D:%.*]]) {
+; CHECK-NEXT: [[ADD1:%.*]] = add i32 [[A]], [[B]]
+; CHECK-NEXT: [[ADD3:%.*]] = sub i32 0, [[D]]
+; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[ADD1]], [[ADD3]]
+; CHECK-NEXT: ret i1 [[CMP]]
+;
+ %add1 = add i32 %a, %b
+ %add2 = add i32 %add1, %c
+ %add3 = add i32 %add2, %d
+ %cmp = icmp eq i32 %add3, %c
+ ret i1 %cmp
+}
+
+; A + B + C - D == B
+define i1 @icmp_common_add_add_sub(i32 %a, i32 %b, i32 %c, i32 %d){
+; CHECK-LABEL: define i1 @icmp_common_add_add_sub(
+; CHECK-SAME: i32 [[A:%.*]], i32 [[B:%.*]], i32 [[C:%.*]], i32 [[D:%.*]]) {
+; CHECK-NEXT: [[ADD2:%.*]] = add i32 [[A]], [[C]]
+; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[ADD2]], [[D]]
+; CHECK-NEXT: ret i1 [[CMP]]
+;
+ %add1 = add i32 %a, %b
+ %add2 = add i32 %add1, %c
+ %sub = sub i32 %add2, %d
+ %cmp = icmp eq i32 %sub, %b
+ ret i1 %cmp
+}
+
+
+; A + B - C + D == B
+define i1 @icmp_common_add_sub_add(i32 %a, i32 %b, i32 %c, i32 %d){
+; CHECK-LABEL: define i1 @icmp_common_add_sub_add(
+; CHECK-SAME: i32 [[A:%.*]], i32 [[B:%.*]], i32 [[C:%.*]], i32 [[D:%.*]]) {
+; CHECK-NEXT: [[SUB:%.*]] = sub i32 [[A]], [[C]]
+; CHECK-NEXT: [[ADD2:%.*]] = sub i32 0, [[D]]
+; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[SUB]], [[ADD2]]
+; CHECK-NEXT: ret i1 [[CMP]]
+;
+ %add1 = add i32 %a, %b
+ %sub = sub i32 %add1, %c
+ %add2 = add i32 %sub, %d
+ %cmp = icmp eq i32 %add2, %b
+ ret i1 %cmp
+}
>From c8c76567e58fee1432df1199a20d87b658d4fe50 Mon Sep 17 00:00:00 2001
From: sun-jacobi <sun1011jacobi at gmail.com>
Date: Thu, 21 Dec 2023 21:18:04 +0900
Subject: [PATCH 5/5] [InstCombine] fixs bug in foldICmpWithCommonFactors
---
.../InstCombine/InstCombineCompares.cpp | 27 +++++++++++--------
.../InstCombine/icmp-eq-common-factor.ll | 2 +-
2 files changed, 17 insertions(+), 12 deletions(-)
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
index 399af8d1133f08..03c04f6d7b6b13 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -4555,27 +4555,32 @@ Instruction *InstCombinerImpl::foldICmpWithCommonFactors(ICmpInst &Cmp,
if (!ICmpInst::isEquality(Pred))
return nullptr;
- SmallVector<BinaryOperator *, 16> worklist(1, LBO);
- Constant *Zero = Constant::getNullValue(LBO->getType());
+ if (LBO->getOpcode() != Instruction::Add &&
+ LBO->getOpcode() != Instruction::Sub)
+ return nullptr;
+
+ SmallVector<BinaryOperator *, 16> worklist;
+
+ auto AddNextBO = [&](Value *Op) {
+ if (BinaryOperator *Next = dyn_cast<BinaryOperator>(Op))
+ worklist.push_back(Next);
+ };
+
+ AddNextBO(LBO->getOperand(0));
+ AddNextBO(LBO->getOperand(1));
while (!worklist.empty()) {
BinaryOperator *BO = worklist.pop_back_val();
if (Value * A; match(BO, m_OneUse(m_c_Add(m_Value(A), m_Specific(RHS))))) {
- if (BO != LBO) {
- replaceInstUsesWith(*BO, A);
- eraseInstFromFunction(*BO);
- }
+ replaceInstUsesWith(*BO, A);
+ eraseInstFromFunction(*BO);
+ Constant *Zero = Constant::getNullValue(LBO->getType());
return new ICmpInst(Pred, LBO, Zero);
}
unsigned Opc = BO->getOpcode();
if (Opc == Instruction::Add || Opc == Instruction::Sub) {
- auto AddNextBO = [&](Value *Op) {
- if (BinaryOperator *Next = dyn_cast<BinaryOperator>(Op))
- worklist.push_back(Next);
- };
-
AddNextBO(BO->getOperand(0));
AddNextBO(BO->getOperand(1));
}
diff --git a/llvm/test/Transforms/InstCombine/icmp-eq-common-factor.ll b/llvm/test/Transforms/InstCombine/icmp-eq-common-factor.ll
index e28c0910c9cae2..d6c3c8c8dfad35 100644
--- a/llvm/test/Transforms/InstCombine/icmp-eq-common-factor.ll
+++ b/llvm/test/Transforms/InstCombine/icmp-eq-common-factor.ll
@@ -14,7 +14,7 @@ define i1 @icmp_common_add_sub(i32 %a, i32 %b, i32 %c){
ret i1 %cmp
}
-; A + B - C == B
+; A + B - C != B
define i1 @icmp_common_add_sub_ne(i32 %a, i32 %b, i32 %c){
; CHECK-LABEL: define i1 @icmp_common_add_sub_ne(
; CHECK-SAME: i32 [[A:%.*]], i32 [[B:%.*]], i32 [[C:%.*]]) {
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