[clang-tools-extra] [InstCombine] Simplify the pattern `a ne/eq (zext (a ne/eq c))` (PR #65852)
via cfe-commits
cfe-commits at lists.llvm.org
Mon Sep 18 07:34:12 PDT 2023
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-llvm-transforms
<details>
<summary>Changes</summary>
This patch folds the pattern `a ne/eq (zext (a ne/eq c))` into a boolean constant or a compare.
Clang vs GCC: https://godbolt.org/z/4ro817WE8
Alive2: https://alive2.llvm.org/ce/z/6z9NRF
Fixes #<!-- -->65073.
---
Full diff: https://github.com/llvm/llvm-project/pull/65852.diff
2 Files Affected:
- (modified) llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp (+62)
- (modified) llvm/test/Transforms/InstCombine/icmp-range.ll (+18-58)
``````````diff
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
index a219dac7acfbe16..d0b62c17ec94358 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -6380,7 +6380,69 @@ Instruction *InstCombinerImpl::foldICmpUsingBoolRange(ICmpInst &I) {
Y->getType()->isIntOrIntVectorTy(1) && Pred == ICmpInst::ICMP_ULE)
return BinaryOperator::CreateOr(Builder.CreateIsNull(X), Y);
+ ICmpInst::Predicate Pred1, Pred2;
const APInt *C;
+ // icmp eq/ne X, (zext (icmp eq/ne X, C))
+ if (match(&I, m_c_ICmp(Pred1, m_Value(X),
+ m_ZExt(m_ICmp(Pred2, m_Deferred(X), m_APInt(C))))) &&
+ ICmpInst::isEquality(Pred1) && ICmpInst::isEquality(Pred2)) {
+ if (C->isZero()) {
+ if (Pred2 == ICmpInst::ICMP_EQ) {
+ // icmp eq X, (zext (icmp eq X, 0)) --> false
+ // icmp ne X, (zext (icmp eq X, 0)) --> true
+ return replaceInstUsesWith(
+ I,
+ Constant::getIntegerValue(
+ I.getType(),
+ APInt(1U, static_cast<uint64_t>(Pred1 == ICmpInst::ICMP_NE))));
+ } else {
+ // icmp eq X, (zext (icmp ne X, 0)) --> icmp ult X, 2
+ // icmp ne X, (zext (icmp ne X, 0)) --> icmp ugt X, 1
+ return ICmpInst::Create(
+ Instruction::ICmp,
+ Pred1 == ICmpInst::ICMP_NE ? ICmpInst::ICMP_UGT
+ : ICmpInst::ICMP_ULT,
+ X,
+ Constant::getIntegerValue(
+ X->getType(), APInt(X->getType()->getScalarSizeInBits(),
+ Pred1 == ICmpInst::ICMP_NE ? 1 : 2)));
+ }
+ } else if (C->isOne()) {
+ if (Pred2 == ICmpInst::ICMP_NE) {
+ // icmp eq X, (zext (icmp ne X, 1)) --> false
+ // icmp ne X, (zext (icmp ne X, 1)) --> true
+ return replaceInstUsesWith(
+ I,
+ Constant::getIntegerValue(
+ I.getType(),
+ APInt(1U, static_cast<uint64_t>(Pred1 == ICmpInst::ICMP_NE))));
+ } else {
+ // icmp eq X, (zext (icmp eq X, 1)) --> icmp ult X, 2
+ // icmp ne X, (zext (icmp eq X, 1)) --> icmp ugt X, 1
+ return ICmpInst::Create(
+ Instruction::ICmp,
+ Pred1 == ICmpInst::ICMP_NE ? ICmpInst::ICMP_UGT
+ : ICmpInst::ICMP_ULT,
+ X,
+ Constant::getIntegerValue(
+ X->getType(), APInt(X->getType()->getScalarSizeInBits(),
+ Pred1 == ICmpInst::ICMP_NE ? 1 : 2)));
+ }
+ } else {
+ // C != 0 && C != 1
+ // icmp eq X, (zext (icmp eq X, C)) --> icmp eq X, 0
+ // icmp eq X, (zext (icmp ne X, C)) --> icmp eq X, 1
+ // icmp ne X, (zext (icmp eq X, C)) --> icmp ne X, 0
+ // icmp ne X, (zext (icmp ne X, C)) --> icmp ne X, 1
+ return ICmpInst::Create(
+ Instruction::ICmp, Pred1, X,
+ Constant::getIntegerValue(
+ X->getType(),
+ APInt(X->getType()->getScalarSizeInBits(),
+ static_cast<uint64_t>(Pred2 == ICmpInst::ICMP_NE))));
+ }
+ }
+
if (match(I.getOperand(0), m_c_Add(m_ZExt(m_Value(X)), m_SExt(m_Value(Y)))) &&
match(I.getOperand(1), m_APInt(C)) &&
X->getType()->isIntOrIntVectorTy(1) &&
diff --git a/llvm/test/Transforms/InstCombine/icmp-range.ll b/llvm/test/Transforms/InstCombine/icmp-range.ll
index a26e760059b43fe..88d5a723747ad5f 100644
--- a/llvm/test/Transforms/InstCombine/icmp-range.ll
+++ b/llvm/test/Transforms/InstCombine/icmp-range.ll
@@ -1037,10 +1037,7 @@ define i1 @icmp_ne_bool_1(ptr %ptr) {
; Tests from PR65073
define i1 @icmp_ne_zext_eq_zero(i32 %a) {
; CHECK-LABEL: @icmp_ne_zext_eq_zero(
-; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[A:%.*]], 0
-; CHECK-NEXT: [[CONV:%.*]] = zext i1 [[CMP]] to i32
-; CHECK-NEXT: [[CMP1:%.*]] = icmp ne i32 [[CONV]], [[A]]
-; CHECK-NEXT: ret i1 [[CMP1]]
+; CHECK-NEXT: ret i1 true
;
%cmp = icmp eq i32 %a, 0
%conv = zext i1 %cmp to i32
@@ -1050,9 +1047,7 @@ define i1 @icmp_ne_zext_eq_zero(i32 %a) {
define i1 @icmp_ne_zext_ne_zero(i32 %a) {
; CHECK-LABEL: @icmp_ne_zext_ne_zero(
-; CHECK-NEXT: [[CMP:%.*]] = icmp ne i32 [[A:%.*]], 0
-; CHECK-NEXT: [[CONV:%.*]] = zext i1 [[CMP]] to i32
-; CHECK-NEXT: [[CMP1:%.*]] = icmp ne i32 [[CONV]], [[A]]
+; CHECK-NEXT: [[CMP1:%.*]] = icmp ugt i32 [[A:%.*]], 1
; CHECK-NEXT: ret i1 [[CMP1]]
;
%cmp = icmp ne i32 %a, 0
@@ -1063,10 +1058,7 @@ define i1 @icmp_ne_zext_ne_zero(i32 %a) {
define i1 @icmp_eq_zext_eq_zero(i32 %a) {
; CHECK-LABEL: @icmp_eq_zext_eq_zero(
-; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[A:%.*]], 0
-; CHECK-NEXT: [[CONV:%.*]] = zext i1 [[CMP]] to i32
-; CHECK-NEXT: [[CMP1:%.*]] = icmp eq i32 [[CONV]], [[A]]
-; CHECK-NEXT: ret i1 [[CMP1]]
+; CHECK-NEXT: ret i1 false
;
%cmp = icmp eq i32 %a, 0
%conv = zext i1 %cmp to i32
@@ -1076,9 +1068,7 @@ define i1 @icmp_eq_zext_eq_zero(i32 %a) {
define i1 @icmp_eq_zext_ne_zero(i32 %a) {
; CHECK-LABEL: @icmp_eq_zext_ne_zero(
-; CHECK-NEXT: [[CMP:%.*]] = icmp ne i32 [[A:%.*]], 0
-; CHECK-NEXT: [[CONV:%.*]] = zext i1 [[CMP]] to i32
-; CHECK-NEXT: [[CMP1:%.*]] = icmp eq i32 [[CONV]], [[A]]
+; CHECK-NEXT: [[CMP1:%.*]] = icmp ult i32 [[A:%.*]], 2
; CHECK-NEXT: ret i1 [[CMP1]]
;
%cmp = icmp ne i32 %a, 0
@@ -1089,9 +1079,7 @@ define i1 @icmp_eq_zext_ne_zero(i32 %a) {
define i1 @icmp_ne_zext_eq_one(i32 %a) {
; CHECK-LABEL: @icmp_ne_zext_eq_one(
-; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[A:%.*]], 1
-; CHECK-NEXT: [[CONV:%.*]] = zext i1 [[CMP]] to i32
-; CHECK-NEXT: [[CMP1:%.*]] = icmp ne i32 [[CONV]], [[A]]
+; CHECK-NEXT: [[CMP1:%.*]] = icmp ugt i32 [[A:%.*]], 1
; CHECK-NEXT: ret i1 [[CMP1]]
;
%cmp = icmp eq i32 %a, 1
@@ -1102,10 +1090,7 @@ define i1 @icmp_ne_zext_eq_one(i32 %a) {
define i1 @icmp_ne_zext_ne_one(i32 %a) {
; CHECK-LABEL: @icmp_ne_zext_ne_one(
-; CHECK-NEXT: [[CMP:%.*]] = icmp ne i32 [[A:%.*]], 1
-; CHECK-NEXT: [[CONV:%.*]] = zext i1 [[CMP]] to i32
-; CHECK-NEXT: [[CMP1:%.*]] = icmp ne i32 [[CONV]], [[A]]
-; CHECK-NEXT: ret i1 [[CMP1]]
+; CHECK-NEXT: ret i1 true
;
%cmp = icmp ne i32 %a, 1
%conv = zext i1 %cmp to i32
@@ -1115,9 +1100,7 @@ define i1 @icmp_ne_zext_ne_one(i32 %a) {
define i1 @icmp_eq_zext_eq_one(i32 %a) {
; CHECK-LABEL: @icmp_eq_zext_eq_one(
-; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[A:%.*]], 1
-; CHECK-NEXT: [[CONV:%.*]] = zext i1 [[CMP]] to i32
-; CHECK-NEXT: [[CMP1:%.*]] = icmp eq i32 [[CONV]], [[A]]
+; CHECK-NEXT: [[CMP1:%.*]] = icmp ult i32 [[A:%.*]], 2
; CHECK-NEXT: ret i1 [[CMP1]]
;
%cmp = icmp eq i32 %a, 1
@@ -1128,10 +1111,7 @@ define i1 @icmp_eq_zext_eq_one(i32 %a) {
define i1 @icmp_eq_zext_ne_one(i32 %a) {
; CHECK-LABEL: @icmp_eq_zext_ne_one(
-; CHECK-NEXT: [[CMP:%.*]] = icmp ne i32 [[A:%.*]], 1
-; CHECK-NEXT: [[CONV:%.*]] = zext i1 [[CMP]] to i32
-; CHECK-NEXT: [[CMP1:%.*]] = icmp eq i32 [[CONV]], [[A]]
-; CHECK-NEXT: ret i1 [[CMP1]]
+; CHECK-NEXT: ret i1 false
;
%cmp = icmp ne i32 %a, 1
%conv = zext i1 %cmp to i32
@@ -1141,9 +1121,7 @@ define i1 @icmp_eq_zext_ne_one(i32 %a) {
define i1 @icmp_ne_zext_eq_non_boolean(i32 %a) {
; CHECK-LABEL: @icmp_ne_zext_eq_non_boolean(
-; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[A:%.*]], 2
-; CHECK-NEXT: [[CONV:%.*]] = zext i1 [[CMP]] to i32
-; CHECK-NEXT: [[CMP1:%.*]] = icmp ne i32 [[CONV]], [[A]]
+; CHECK-NEXT: [[CMP1:%.*]] = icmp ne i32 [[A:%.*]], 0
; CHECK-NEXT: ret i1 [[CMP1]]
;
%cmp = icmp eq i32 %a, 2
@@ -1154,9 +1132,7 @@ define i1 @icmp_ne_zext_eq_non_boolean(i32 %a) {
define i1 @icmp_ne_zext_ne_non_boolean(i32 %a) {
; CHECK-LABEL: @icmp_ne_zext_ne_non_boolean(
-; CHECK-NEXT: [[CMP:%.*]] = icmp ne i32 [[A:%.*]], 2
-; CHECK-NEXT: [[CONV:%.*]] = zext i1 [[CMP]] to i32
-; CHECK-NEXT: [[CMP1:%.*]] = icmp ne i32 [[CONV]], [[A]]
+; CHECK-NEXT: [[CMP1:%.*]] = icmp ne i32 [[A:%.*]], 1
; CHECK-NEXT: ret i1 [[CMP1]]
;
%cmp = icmp ne i32 %a, 2
@@ -1167,9 +1143,7 @@ define i1 @icmp_ne_zext_ne_non_boolean(i32 %a) {
define i1 @icmp_eq_zext_eq_non_boolean(i32 %a) {
; CHECK-LABEL: @icmp_eq_zext_eq_non_boolean(
-; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[A:%.*]], 2
-; CHECK-NEXT: [[CONV:%.*]] = zext i1 [[CMP]] to i32
-; CHECK-NEXT: [[CMP1:%.*]] = icmp eq i32 [[CONV]], [[A]]
+; CHECK-NEXT: [[CMP1:%.*]] = icmp eq i32 [[A:%.*]], 0
; CHECK-NEXT: ret i1 [[CMP1]]
;
%cmp = icmp eq i32 %a, 2
@@ -1180,9 +1154,7 @@ define i1 @icmp_eq_zext_eq_non_boolean(i32 %a) {
define i1 @icmp_eq_zext_ne_non_boolean(i32 %a) {
; CHECK-LABEL: @icmp_eq_zext_ne_non_boolean(
-; CHECK-NEXT: [[CMP:%.*]] = icmp ne i32 [[A:%.*]], 2
-; CHECK-NEXT: [[CONV:%.*]] = zext i1 [[CMP]] to i32
-; CHECK-NEXT: [[CMP1:%.*]] = icmp eq i32 [[CONV]], [[A]]
+; CHECK-NEXT: [[CMP1:%.*]] = icmp eq i32 [[A:%.*]], 1
; CHECK-NEXT: ret i1 [[CMP1]]
;
%cmp = icmp ne i32 %a, 2
@@ -1192,11 +1164,8 @@ define i1 @icmp_eq_zext_ne_non_boolean(i32 %a) {
}
define <2 x i1> @icmp_ne_zext_eq_zero_vec(<2 x i32> %a) {
-; CHECK-LABEL: @icmp_ne_zext_eq_zero_vec(
-; CHECK-NEXT: [[CMP:%.*]] = icmp eq <2 x i32> [[A:%.*]], zeroinitializer
-; CHECK-NEXT: [[CONV:%.*]] = zext <2 x i1> [[CMP]] to <2 x i32>
-; CHECK-NEXT: [[CMP1:%.*]] = icmp ne <2 x i32> [[CONV]], [[A]]
-; CHECK-NEXT: ret <2 x i1> [[CMP1]]
+; CHECK-LABEL: @icmp_ne_zext_eq_zero_vec
+; CHECK-NEXT: ret <2 x i1> <i1 true, i1 true>
;
%cmp = icmp eq <2 x i32> %a, <i32 0, i32 0>
%conv = zext <2 x i1> %cmp to <2 x i32>
@@ -1206,9 +1175,7 @@ define <2 x i1> @icmp_ne_zext_eq_zero_vec(<2 x i32> %a) {
define <2 x i1> @icmp_ne_zext_ne_zero_vec(<2 x i32> %a) {
; CHECK-LABEL: @icmp_ne_zext_ne_zero_vec(
-; CHECK-NEXT: [[CMP:%.*]] = icmp ne <2 x i32> [[A:%.*]], zeroinitializer
-; CHECK-NEXT: [[CONV:%.*]] = zext <2 x i1> [[CMP]] to <2 x i32>
-; CHECK-NEXT: [[CMP1:%.*]] = icmp ne <2 x i32> [[CONV]], [[A]]
+; CHECK-NEXT: [[CMP1:%.*]] = icmp ugt <2 x i32> [[A:%.*]], <i32 1, i32 1>
; CHECK-NEXT: ret <2 x i1> [[CMP1]]
;
%cmp = icmp ne <2 x i32> %a, <i32 0, i32 0>
@@ -1219,9 +1186,7 @@ define <2 x i1> @icmp_ne_zext_ne_zero_vec(<2 x i32> %a) {
define <2 x i1> @icmp_ne_zext_eq_one_vec(<2 x i32> %a) {
; CHECK-LABEL: @icmp_ne_zext_eq_one_vec(
-; CHECK-NEXT: [[CMP:%.*]] = icmp eq <2 x i32> [[A:%.*]], <i32 1, i32 1>
-; CHECK-NEXT: [[CONV:%.*]] = zext <2 x i1> [[CMP]] to <2 x i32>
-; CHECK-NEXT: [[CMP1:%.*]] = icmp ne <2 x i32> [[CONV]], [[A]]
+; CHECK-NEXT: [[CMP1:%.*]] = icmp ugt <2 x i32> [[A:%.*]], <i32 1, i32 1>
; CHECK-NEXT: ret <2 x i1> [[CMP1]]
;
%cmp = icmp eq <2 x i32> %a, <i32 1, i32 1>
@@ -1232,10 +1197,7 @@ define <2 x i1> @icmp_ne_zext_eq_one_vec(<2 x i32> %a) {
define <2 x i1> @icmp_ne_zext_ne_one_vec(<2 x i32> %a) {
; CHECK-LABEL: @icmp_ne_zext_ne_one_vec(
-; CHECK-NEXT: [[CMP:%.*]] = icmp ne <2 x i32> [[A:%.*]], <i32 1, i32 1>
-; CHECK-NEXT: [[CONV:%.*]] = zext <2 x i1> [[CMP]] to <2 x i32>
-; CHECK-NEXT: [[CMP1:%.*]] = icmp ne <2 x i32> [[CONV]], [[A]]
-; CHECK-NEXT: ret <2 x i1> [[CMP1]]
+; CHECK-NEXT: ret <2 x i1> <i1 true, i1 true>
;
%cmp = icmp ne <2 x i32> %a, <i32 1, i32 1>
%conv = zext <2 x i1> %cmp to <2 x i32>
@@ -1245,9 +1207,7 @@ define <2 x i1> @icmp_ne_zext_ne_one_vec(<2 x i32> %a) {
define <2 x i1> @icmp_ne_zext_eq_non_boolean_vec(<2 x i32> %a) {
; CHECK-LABEL: @icmp_ne_zext_eq_non_boolean_vec(
-; CHECK-NEXT: [[CMP:%.*]] = icmp eq <2 x i32> [[A:%.*]], <i32 2, i32 2>
-; CHECK-NEXT: [[CONV:%.*]] = zext <2 x i1> [[CMP]] to <2 x i32>
-; CHECK-NEXT: [[CMP1:%.*]] = icmp ne <2 x i32> [[CONV]], [[A]]
+; CHECK-NEXT: [[CMP1:%.*]] = icmp ne <2 x i32> [[A:%.*]], zeroinitializer
; CHECK-NEXT: ret <2 x i1> [[CMP1]]
;
%cmp = icmp eq <2 x i32> %a, <i32 2, i32 2>
``````````
</details>
https://github.com/llvm/llvm-project/pull/65852
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