[llvm] [InstSimplify] `A == MIN_INT ? B != MIN_INT : A < B` to `A < B` (PR #120177)
via llvm-commits
llvm-commits at lists.llvm.org
Mon Dec 16 19:37:42 PST 2024
https://github.com/veera-sivarajan created https://github.com/llvm/llvm-project/pull/120177
This PR simplifies:
`A == MIN_INT ? B != MIN_INT : A < B` to `A < B`
`A == MAX_INT ? B != MAX_INT : A > B` to `A > B`
Proof: https://alive2.llvm.org/ce/z/bR6E2s
This helps in optimizing comparison of optional unsigned non-zero types in https://github.com/rust-lang/rust/issues/49892.
Rust compiler's current output: https://rust.godbolt.org/z/9fxfq3Gn8
>From e306711b0cd65270a65077094391edd0f09179f3 Mon Sep 17 00:00:00 2001
From: Veera <sveera.2001 at gmail.com>
Date: Sun, 15 Dec 2024 06:19:31 +0000
Subject: [PATCH 1/2] Add Test
---
.../select-with-extreme-eq-cond.ll | 405 ++++++++++++++++++
1 file changed, 405 insertions(+)
create mode 100644 llvm/test/Transforms/InstSimplify/select-with-extreme-eq-cond.ll
diff --git a/llvm/test/Transforms/InstSimplify/select-with-extreme-eq-cond.ll b/llvm/test/Transforms/InstSimplify/select-with-extreme-eq-cond.ll
new file mode 100644
index 00000000000000..0ed4453b2a0ead
--- /dev/null
+++ b/llvm/test/Transforms/InstSimplify/select-with-extreme-eq-cond.ll
@@ -0,0 +1,405 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt < %s -passes=instcombine -S | FileCheck %s
+
+define i1 @compare_unsigned_min(i8 %0, i8 %1) {
+; CHECK-LABEL: define i1 @compare_unsigned_min(
+; CHECK-SAME: i8 [[TMP0:%.*]], i8 [[TMP1:%.*]]) {
+; CHECK-NEXT: [[START:.*:]]
+; CHECK-NEXT: [[TMP4:%.*]] = icmp eq i8 [[TMP0]], 0
+; CHECK-NEXT: [[TMP3:%.*]] = icmp ne i8 [[TMP1]], 0
+; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i8 [[TMP0]], [[TMP1]]
+; CHECK-NEXT: [[RESULT:%.*]] = select i1 [[TMP4]], i1 [[TMP3]], i1 [[TMP2]]
+; CHECK-NEXT: ret i1 [[RESULT]]
+;
+start:
+ %2 = icmp eq i8 %0, 0
+ %3 = icmp ne i8 %1, 0
+ %4 = icmp ult i8 %0, %1
+ %result = select i1 %2, i1 %3, i1 %4
+ ret i1 %result
+}
+
+define i1 @compare_signed_min(i8 %0, i8 %1) {
+; CHECK-LABEL: define i1 @compare_signed_min(
+; CHECK-SAME: i8 [[TMP0:%.*]], i8 [[TMP1:%.*]]) {
+; CHECK-NEXT: [[START:.*:]]
+; CHECK-NEXT: [[TMP2:%.*]] = icmp eq i8 [[TMP0]], -128
+; CHECK-NEXT: [[TMP3:%.*]] = icmp ne i8 [[TMP1]], -128
+; CHECK-NEXT: [[TMP4:%.*]] = icmp slt i8 [[TMP0]], [[TMP1]]
+; CHECK-NEXT: [[RESULT:%.*]] = select i1 [[TMP2]], i1 [[TMP3]], i1 [[TMP4]]
+; CHECK-NEXT: ret i1 [[RESULT]]
+;
+start:
+ %2 = icmp eq i8 %0, -128
+ %3 = icmp ne i8 %1, -128
+ %4 = icmp slt i8 %0, %1
+ %result = select i1 %2, i1 %3, i1 %4
+ ret i1 %result
+}
+
+define i1 @compare_unsigned_max(i8 %0, i8 %1) {
+; CHECK-LABEL: define i1 @compare_unsigned_max(
+; CHECK-SAME: i8 [[TMP0:%.*]], i8 [[TMP1:%.*]]) {
+; CHECK-NEXT: [[START:.*:]]
+; CHECK-NEXT: [[TMP2:%.*]] = icmp eq i8 [[TMP0]], -1
+; CHECK-NEXT: [[TMP3:%.*]] = icmp ne i8 [[TMP1]], -1
+; CHECK-NEXT: [[TMP4:%.*]] = icmp ugt i8 [[TMP0]], [[TMP1]]
+; CHECK-NEXT: [[RESULT:%.*]] = select i1 [[TMP2]], i1 [[TMP3]], i1 [[TMP4]]
+; CHECK-NEXT: ret i1 [[RESULT]]
+;
+start:
+ %2 = icmp eq i8 %0, 255
+ %3 = icmp ne i8 %1, 255
+ %4 = icmp ugt i8 %0, %1
+ %result = select i1 %2, i1 %3, i1 %4
+ ret i1 %result
+}
+
+define i1 @compare_signed_max(i8 %0, i8 %1) {
+; CHECK-LABEL: define i1 @compare_signed_max(
+; CHECK-SAME: i8 [[TMP0:%.*]], i8 [[TMP1:%.*]]) {
+; CHECK-NEXT: [[START:.*:]]
+; CHECK-NEXT: [[TMP2:%.*]] = icmp eq i8 [[TMP0]], 127
+; CHECK-NEXT: [[TMP3:%.*]] = icmp ne i8 [[TMP1]], 127
+; CHECK-NEXT: [[TMP4:%.*]] = icmp sgt i8 [[TMP0]], [[TMP1]]
+; CHECK-NEXT: [[RESULT:%.*]] = select i1 [[TMP2]], i1 [[TMP3]], i1 [[TMP4]]
+; CHECK-NEXT: ret i1 [[RESULT]]
+;
+start:
+ %2 = icmp eq i8 %0, 127
+ %3 = icmp ne i8 %1, 127
+ %4 = icmp sgt i8 %0, %1
+ %result = select i1 %2, i1 %3, i1 %4
+ ret i1 %result
+}
+
+define i1 @relational_cmp_unsigned_min(i8 %0, i8 %1) {
+; CHECK-LABEL: define i1 @relational_cmp_unsigned_min(
+; CHECK-SAME: i8 [[TMP0:%.*]], i8 [[TMP1:%.*]]) {
+; CHECK-NEXT: [[START:.*:]]
+; CHECK-NEXT: [[TMP2:%.*]] = icmp eq i8 [[TMP0]], 0
+; CHECK-NEXT: [[TMP3:%.*]] = icmp ne i8 [[TMP1]], 0
+; CHECK-NEXT: [[TMP4:%.*]] = icmp ult i8 [[TMP0]], [[TMP1]]
+; CHECK-NEXT: [[RESULT:%.*]] = select i1 [[TMP2]], i1 [[TMP3]], i1 [[TMP4]]
+; CHECK-NEXT: ret i1 [[RESULT]]
+;
+start:
+ %2 = icmp ule i8 %0, 0
+ %3 = icmp ugt i8 %1, 0
+ %4 = icmp ult i8 %0, %1
+ %result = select i1 %2, i1 %3, i1 %4
+ ret i1 %result
+}
+
+define i1 @relational_cmp_signed_min(i8 %0, i8 %1) {
+; CHECK-LABEL: define i1 @relational_cmp_signed_min(
+; CHECK-SAME: i8 [[TMP0:%.*]], i8 [[TMP1:%.*]]) {
+; CHECK-NEXT: [[START:.*:]]
+; CHECK-NEXT: [[TMP2:%.*]] = icmp eq i8 [[TMP0]], -128
+; CHECK-NEXT: [[TMP3:%.*]] = icmp ne i8 [[TMP1]], -128
+; CHECK-NEXT: [[TMP4:%.*]] = icmp slt i8 [[TMP0]], [[TMP1]]
+; CHECK-NEXT: [[RESULT:%.*]] = select i1 [[TMP2]], i1 [[TMP3]], i1 [[TMP4]]
+; CHECK-NEXT: ret i1 [[RESULT]]
+;
+start:
+ %2 = icmp sle i8 %0, -128
+ %3 = icmp sgt i8 %1, -128
+ %4 = icmp slt i8 %0, %1
+ %result = select i1 %2, i1 %3, i1 %4
+ ret i1 %result
+}
+
+define i1 @relational_cmp_unsigned_max(i8 %0, i8 %1) {
+; CHECK-LABEL: define i1 @relational_cmp_unsigned_max(
+; CHECK-SAME: i8 [[TMP0:%.*]], i8 [[TMP1:%.*]]) {
+; CHECK-NEXT: [[START:.*:]]
+; CHECK-NEXT: [[TMP2:%.*]] = icmp eq i8 [[TMP0]], -1
+; CHECK-NEXT: [[TMP3:%.*]] = icmp ne i8 [[TMP1]], -1
+; CHECK-NEXT: [[TMP4:%.*]] = icmp ugt i8 [[TMP0]], [[TMP1]]
+; CHECK-NEXT: [[RESULT:%.*]] = select i1 [[TMP2]], i1 [[TMP3]], i1 [[TMP4]]
+; CHECK-NEXT: ret i1 [[RESULT]]
+;
+start:
+ %2 = icmp uge i8 %0, 255
+ %3 = icmp ult i8 %1, 255
+ %4 = icmp ugt i8 %0, %1
+ %result = select i1 %2, i1 %3, i1 %4
+ ret i1 %result
+}
+
+define i1 @relational_cmp_signed_max(i8 %0, i8 %1) {
+; CHECK-LABEL: define i1 @relational_cmp_signed_max(
+; CHECK-SAME: i8 [[TMP0:%.*]], i8 [[TMP1:%.*]]) {
+; CHECK-NEXT: [[START:.*:]]
+; CHECK-NEXT: [[TMP2:%.*]] = icmp eq i8 [[TMP0]], 127
+; CHECK-NEXT: [[TMP3:%.*]] = icmp ne i8 [[TMP1]], 127
+; CHECK-NEXT: [[TMP4:%.*]] = icmp sgt i8 [[TMP0]], [[TMP1]]
+; CHECK-NEXT: [[RESULT:%.*]] = select i1 [[TMP2]], i1 [[TMP3]], i1 [[TMP4]]
+; CHECK-NEXT: ret i1 [[RESULT]]
+;
+start:
+ %2 = icmp sge i8 %0, 127
+ %3 = icmp slt i8 %1, 127
+ %4 = icmp sgt i8 %0, %1
+ %result = select i1 %2, i1 %3, i1 %4
+ ret i1 %result
+}
+
+declare void @use(i1)
+
+define i1 @compare_signed_max_multiuse(i8 %0, i8 %1) {
+; CHECK-LABEL: define i1 @compare_signed_max_multiuse(
+; CHECK-SAME: i8 [[TMP0:%.*]], i8 [[TMP1:%.*]]) {
+; CHECK-NEXT: [[START:.*:]]
+; CHECK-NEXT: [[TMP2:%.*]] = icmp eq i8 [[TMP0]], 127
+; CHECK-NEXT: [[TMP3:%.*]] = icmp ne i8 [[TMP1]], 127
+; CHECK-NEXT: [[TMP4:%.*]] = icmp sgt i8 [[TMP0]], [[TMP1]]
+; CHECK-NEXT: call void @use(i1 [[TMP4]])
+; CHECK-NEXT: [[RESULT:%.*]] = select i1 [[TMP2]], i1 [[TMP3]], i1 [[TMP4]]
+; CHECK-NEXT: ret i1 [[RESULT]]
+;
+start:
+ %2 = icmp eq i8 %0, 127
+ %3 = icmp ne i8 %1, 127
+ %4 = icmp sgt i8 %0, %1
+ call void @use(i1 %4)
+ %result = select i1 %2, i1 %3, i1 %4
+ ret i1 %result
+}
+
+define i1 @compare_signed_min_samesign(i8 %0, i8 %1) {
+; CHECK-LABEL: define i1 @compare_signed_min_samesign(
+; CHECK-SAME: i8 [[TMP0:%.*]], i8 [[TMP1:%.*]]) {
+; CHECK-NEXT: [[START:.*:]]
+; CHECK-NEXT: [[TMP2:%.*]] = icmp eq i8 [[TMP0]], -128
+; CHECK-NEXT: [[TMP3:%.*]] = icmp ne i8 [[TMP1]], -128
+; CHECK-NEXT: [[TMP4:%.*]] = icmp samesign slt i8 [[TMP0]], [[TMP1]]
+; CHECK-NEXT: [[RESULT:%.*]] = select i1 [[TMP2]], i1 [[TMP3]], i1 [[TMP4]]
+; CHECK-NEXT: ret i1 [[RESULT]]
+;
+start:
+ %2 = icmp eq i8 %0, -128
+ %3 = icmp ne i8 %1, -128
+ %4 = icmp samesign slt i8 %0, %1
+ %result = select i1 %2, i1 %3, i1 %4
+ ret i1 %result
+}
+
+define i1 @compare_flipped(i8 %0, i8 %1) {
+; CHECK-LABEL: define i1 @compare_flipped(
+; CHECK-SAME: i8 [[TMP0:%.*]], i8 [[TMP1:%.*]]) {
+; CHECK-NEXT: [[START:.*:]]
+; CHECK-NEXT: [[TMP2:%.*]] = icmp eq i8 [[TMP0]], 0
+; CHECK-NEXT: [[TMP3:%.*]] = icmp ne i8 [[TMP1]], 0
+; CHECK-NEXT: [[TMP4:%.*]] = icmp ugt i8 [[TMP1]], [[TMP0]]
+; CHECK-NEXT: [[RESULT:%.*]] = select i1 [[TMP2]], i1 [[TMP3]], i1 [[TMP4]]
+; CHECK-NEXT: ret i1 [[RESULT]]
+;
+start:
+ %2 = icmp eq i8 %0, 0
+ %3 = icmp ne i8 %1, 0
+ %4 = icmp ugt i8 %1, %0
+ %result = select i1 %2, i1 %3, i1 %4
+ ret i1 %result
+}
+
+define i1 @compare_swapped(i8 %0, i8 %1) {
+; CHECK-LABEL: define i1 @compare_swapped(
+; CHECK-SAME: i8 [[TMP0:%.*]], i8 [[TMP1:%.*]]) {
+; CHECK-NEXT: [[START:.*:]]
+; CHECK-NEXT: [[DOTNOT:%.*]] = icmp eq i8 [[TMP0]], 0
+; CHECK-NEXT: [[TMP2:%.*]] = icmp ne i8 [[TMP1]], 0
+; CHECK-NEXT: [[RESULT:%.*]] = icmp ult i8 [[TMP0]], [[TMP1]]
+; CHECK-NEXT: [[RESULT1:%.*]] = select i1 [[DOTNOT]], i1 [[TMP2]], i1 [[RESULT]]
+; CHECK-NEXT: ret i1 [[RESULT1]]
+;
+start:
+ %2 = icmp ne i8 %0, 0
+ %3 = icmp ne i8 %1, 0
+ %4 = icmp ult i8 %0, %1
+ %result = select i1 %2, i1 %4, i1 %3
+ ret i1 %result
+}
+
+define i1 @compare_swapped_flipped_unsigned_max(i8 %0, i8 %1) {
+; CHECK-LABEL: define i1 @compare_swapped_flipped_unsigned_max(
+; CHECK-SAME: i8 [[TMP0:%.*]], i8 [[TMP1:%.*]]) {
+; CHECK-NEXT: [[START:.*:]]
+; CHECK-NEXT: [[DOTNOT:%.*]] = icmp eq i8 [[TMP0]], -1
+; CHECK-NEXT: [[TMP3:%.*]] = icmp ne i8 [[TMP1]], -1
+; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i8 [[TMP1]], [[TMP0]]
+; CHECK-NEXT: [[RESULT:%.*]] = select i1 [[DOTNOT]], i1 [[TMP3]], i1 [[TMP2]]
+; CHECK-NEXT: ret i1 [[RESULT]]
+;
+start:
+ %2 = icmp ne i8 %0, 255
+ %3 = icmp ne i8 %1, 255
+ %4 = icmp ult i8 %1, %0
+ %result = select i1 %2, i1 %4, i1 %3
+ ret i1 %result
+}
+
+define i1 @compare_unsigned_min_illegal_type(i9 %0, i9 %1) {
+; CHECK-LABEL: define i1 @compare_unsigned_min_illegal_type(
+; CHECK-SAME: i9 [[TMP0:%.*]], i9 [[TMP1:%.*]]) {
+; CHECK-NEXT: [[START:.*:]]
+; CHECK-NEXT: [[TMP4:%.*]] = icmp eq i9 [[TMP0]], 0
+; CHECK-NEXT: [[TMP3:%.*]] = icmp ne i9 [[TMP1]], 0
+; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i9 [[TMP0]], [[TMP1]]
+; CHECK-NEXT: [[RESULT:%.*]] = select i1 [[TMP4]], i1 [[TMP3]], i1 [[TMP2]]
+; CHECK-NEXT: ret i1 [[RESULT]]
+;
+start:
+ %2 = icmp eq i9 %0, 0
+ %3 = icmp ne i9 %1, 0
+ %4 = icmp ult i9 %0, %1
+ %result = select i1 %2, i1 %3, i1 %4
+ ret i1 %result
+}
+
+define <2 x i1> @compare_vector(<2 x i8> %x, <2 x i8> %y) {
+; CHECK-LABEL: define <2 x i1> @compare_vector(
+; CHECK-SAME: <2 x i8> [[X:%.*]], <2 x i8> [[Y:%.*]]) {
+; CHECK-NEXT: [[TMP3:%.*]] = icmp eq <2 x i8> [[X]], zeroinitializer
+; CHECK-NEXT: [[TMP2:%.*]] = icmp ne <2 x i8> [[Y]], zeroinitializer
+; CHECK-NEXT: [[TMP1:%.*]] = icmp ult <2 x i8> [[X]], [[Y]]
+; CHECK-NEXT: [[RESULT:%.*]] = select <2 x i1> [[TMP3]], <2 x i1> [[TMP2]], <2 x i1> [[TMP1]]
+; CHECK-NEXT: ret <2 x i1> [[RESULT]]
+;
+ %2 = icmp eq <2 x i8> %x, <i8 0, i8 0>
+ %3 = icmp ne <2 x i8> %y, <i8 0, i8 0>
+ %4 = icmp ult <2 x i8> %x, %y
+ %result = select <2 x i1> %2, <2 x i1> %3, <2 x i1> %4
+ ret <2 x i1> %result
+}
+
+define i1 @compare_float_negative(half %0, half %1) {
+; CHECK-LABEL: define i1 @compare_float_negative(
+; CHECK-SAME: half [[TMP0:%.*]], half [[TMP1:%.*]]) {
+; CHECK-NEXT: [[START:.*:]]
+; CHECK-NEXT: [[TMP2:%.*]] = fcmp oeq half [[TMP0]], 0xH0000
+; CHECK-NEXT: [[TMP3:%.*]] = fcmp one half [[TMP1]], 0xH0000
+; CHECK-NEXT: [[TMP4:%.*]] = fcmp ult half [[TMP0]], [[TMP1]]
+; CHECK-NEXT: [[RESULT:%.*]] = select i1 [[TMP2]], i1 [[TMP3]], i1 [[TMP4]]
+; CHECK-NEXT: ret i1 [[RESULT]]
+;
+start:
+ %2 = fcmp oeq half %0, 0.0
+ %3 = fcmp one half %1, 0.0
+ %4 = fcmp ult half %0, %1
+ %result = select i1 %2, i1 %3, i1 %4
+ ret i1 %result
+}
+
+define i1 @compare_unsigned_max_swapped_lhs_rhs_negative(i8 %0, i8 %1) {
+; CHECK-LABEL: define i1 @compare_unsigned_max_swapped_lhs_rhs_negative(
+; CHECK-SAME: i8 [[TMP0:%.*]], i8 [[TMP1:%.*]]) {
+; CHECK-NEXT: [[START:.*:]]
+; CHECK-NEXT: [[TMP2:%.*]] = icmp eq i8 [[TMP0]], -1
+; CHECK-NEXT: [[DOTNOT:%.*]] = icmp ne i8 [[TMP1]], -1
+; CHECK-NEXT: [[RESULT:%.*]] = select i1 [[DOTNOT]], i1 [[TMP2]], i1 false
+; CHECK-NEXT: ret i1 [[RESULT]]
+;
+start:
+ %2 = icmp eq i8 %0, 255
+ %3 = icmp ne i8 %1, 255
+ %4 = icmp ugt i8 %0, %1
+ %result = select i1 %3, i1 %2, i1 %4
+ ret i1 %result
+}
+
+define i1 @compare_signed_min_negative(i8 %0, i8 %1) {
+; CHECK-LABEL: define i1 @compare_signed_min_negative(
+; CHECK-SAME: i8 [[TMP0:%.*]], i8 [[TMP1:%.*]]) {
+; CHECK-NEXT: [[START:.*:]]
+; CHECK-NEXT: [[TMP2:%.*]] = icmp eq i8 [[TMP0]], -127
+; CHECK-NEXT: [[TMP3:%.*]] = icmp ne i8 [[TMP1]], -127
+; CHECK-NEXT: [[TMP4:%.*]] = icmp slt i8 [[TMP0]], [[TMP1]]
+; CHECK-NEXT: [[RESULT:%.*]] = select i1 [[TMP2]], i1 [[TMP3]], i1 [[TMP4]]
+; CHECK-NEXT: ret i1 [[RESULT]]
+;
+start:
+ %2 = icmp eq i8 %0, -127
+ %3 = icmp ne i8 %1, -127
+ %4 = icmp slt i8 %0, %1
+ %result = select i1 %2, i1 %3, i1 %4
+ ret i1 %result
+}
+
+define i1 @compare_unsigned_max_negative(i8 %0, i8 %1) {
+; CHECK-LABEL: define i1 @compare_unsigned_max_negative(
+; CHECK-SAME: i8 [[TMP0:%.*]], i8 [[TMP1:%.*]]) {
+; CHECK-NEXT: [[START:.*:]]
+; CHECK-NEXT: [[TMP2:%.*]] = icmp eq i8 [[TMP0]], -1
+; CHECK-NEXT: [[TMP3:%.*]] = icmp ne i8 [[TMP1]], -1
+; CHECK-NEXT: [[TMP4:%.*]] = icmp ult i8 [[TMP0]], [[TMP1]]
+; CHECK-NEXT: [[RESULT:%.*]] = select i1 [[TMP2]], i1 [[TMP3]], i1 [[TMP4]]
+; CHECK-NEXT: ret i1 [[RESULT]]
+;
+start:
+ %2 = icmp eq i8 %0, 255
+ %3 = icmp ne i8 %1, 255
+ %4 = icmp ult i8 %0, %1
+ %result = select i1 %2, i1 %3, i1 %4
+ ret i1 %result
+}
+
+define i1 @non_strict_op_negative(i8 %0, i8 %1) {
+; CHECK-LABEL: define i1 @non_strict_op_negative(
+; CHECK-SAME: i8 [[TMP0:%.*]], i8 [[TMP1:%.*]]) {
+; CHECK-NEXT: [[START:.*:]]
+; CHECK-NEXT: [[TMP2:%.*]] = icmp eq i8 [[TMP0]], 0
+; CHECK-NEXT: [[TMP3:%.*]] = icmp ne i8 [[TMP1]], 0
+; CHECK-NEXT: [[TMP4:%.*]] = icmp ule i8 [[TMP0]], [[TMP1]]
+; CHECK-NEXT: [[RESULT:%.*]] = select i1 [[TMP2]], i1 [[TMP3]], i1 [[TMP4]]
+; CHECK-NEXT: ret i1 [[RESULT]]
+;
+start:
+ %2 = icmp eq i8 %0, 0
+ %3 = icmp ne i8 %1, 0
+ %4 = icmp ule i8 %0, %1
+ %result = select i1 %2, i1 %3, i1 %4
+ ret i1 %result
+}
+
+define i1 @compare_poison_negative(i8 %0, i8 %1) {
+; CHECK-LABEL: define i1 @compare_poison_negative(
+; CHECK-SAME: i8 [[TMP0:%.*]], i8 [[TMP1:%.*]]) {
+; CHECK-NEXT: [[START:.*:]]
+; CHECK-NEXT: ret i1 poison
+;
+start:
+ %2 = icmp eq i8 %0, 0
+ %3 = icmp ne i8 poison, 0
+ %4 = icmp ult i8 %0, poison
+ %result = select i1 %2, i1 %3, i1 %4
+ ret i1 %result
+}
+
+define i1 @compare_cond_poison_negative(i8 %0, i8 %1) {
+; CHECK-LABEL: define i1 @compare_cond_poison_negative(
+; CHECK-SAME: i8 [[TMP0:%.*]], i8 [[TMP1:%.*]]) {
+; CHECK-NEXT: [[START:.*:]]
+; CHECK-NEXT: ret i1 poison
+;
+start:
+ %2 = icmp eq i8 %0, poison
+ %3 = icmp ne i8 %1, 0
+ %4 = icmp ult i8 %0, %1
+ %result = select i1 %2, i1 %3, i1 %4
+ ret i1 %result
+}
+
+define i1 @compare_true_poison_negative(i8 %0, i8 %1) {
+; CHECK-LABEL: define i1 @compare_true_poison_negative(
+; CHECK-SAME: i8 [[TMP0:%.*]], i8 [[TMP1:%.*]]) {
+; CHECK-NEXT: [[START:.*:]]
+; CHECK-NEXT: ret i1 poison
+;
+start:
+ %2 = icmp eq i8 %0, poison
+ %3 = icmp ne i8 %1, 0
+ %4 = icmp ult i8 %0, %1
+ %result = select i1 %2, i1 poison, i1 %4
+ ret i1 %result
+}
>From 92fb27ec298a488c25fc93c13cfd2de2e7a0d1f4 Mon Sep 17 00:00:00 2001
From: Veera <sveera.2001 at gmail.com>
Date: Tue, 17 Dec 2024 03:29:09 +0000
Subject: [PATCH 2/2] Fold `A == MIN_INT ? B != MIN_INT : A < B` to `A < B`
---
llvm/lib/Analysis/InstructionSimplify.cpp | 44 ++++++++++-
.../select-with-extreme-eq-cond.ll | 75 ++++---------------
2 files changed, 58 insertions(+), 61 deletions(-)
diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp
index 3325cd972cf1eb..fcbaaafe69ec48 100644
--- a/llvm/lib/Analysis/InstructionSimplify.cpp
+++ b/llvm/lib/Analysis/InstructionSimplify.cpp
@@ -4608,6 +4608,45 @@ static Value *simplifySelectWithEquivalence(Value *CmpLHS, Value *CmpRHS,
return nullptr;
}
+/// `A == MIN_INT ? B != MIN_INT : A < B` --> `A < B`
+/// `A == MAX_INT ? B != MAX_INT : A > B` --> `A > B`
+static Value *foldSelectWithExtremeEqCond(Value *CmpLHS, Value *CmpRHS,
+ Value *TrueVal, Value *FalseVal) {
+ CmpPredicate Pred;
+ Value *A, *B;
+
+ if (!match(FalseVal, m_ICmp(Pred, m_Value(A), m_Value(B))))
+ return nullptr;
+
+ // make sure `CmpLHS` is on the LHS of `FalseVal`.
+ if (match(CmpLHS, m_Specific(B))) {
+ std::swap(A, B);
+ Pred = CmpInst::getSwappedPredicate(Pred);
+ }
+
+ APInt C;
+ unsigned NumBits = A->getType()->getScalarSizeInBits();
+
+ if (ICmpInst::isLT(Pred)) {
+ C = CmpInst::isSigned(Pred) ? APInt::getSignedMinValue(NumBits)
+ : APInt::getMinValue(NumBits);
+ } else if (ICmpInst::isGT(Pred)) {
+ C = CmpInst::isSigned(Pred) ? APInt::getSignedMaxValue(NumBits)
+ : APInt::getMaxValue(NumBits);
+ } else {
+ return nullptr;
+ }
+
+ if (!match(CmpLHS, m_Specific(A)) || !match(CmpRHS, m_SpecificInt(C)))
+ return nullptr;
+
+ if (!match(TrueVal, m_SpecificICmp(ICmpInst::ICMP_NE, m_Specific(B),
+ m_SpecificInt(C))))
+ return nullptr;
+
+ return FalseVal;
+}
+
/// Try to simplify a select instruction when its condition operand is an
/// integer comparison.
static Value *simplifySelectWithICmpCond(Value *CondVal, Value *TrueVal,
@@ -4728,6 +4767,10 @@ static Value *simplifySelectWithICmpCond(Value *CondVal, Value *TrueVal,
Q, MaxRecurse))
return V;
}
+
+ if (Value *V =
+ foldSelectWithExtremeEqCond(CmpLHS, CmpRHS, TrueVal, FalseVal))
+ return V;
}
return nullptr;
@@ -7141,7 +7184,6 @@ static Value *simplifyInstructionWithOperands(Instruction *I,
NewOps[1], I->getFastMathFlags(), Q, MaxRecurse);
case Instruction::Select:
return simplifySelectInst(NewOps[0], NewOps[1], NewOps[2], Q, MaxRecurse);
- break;
case Instruction::GetElementPtr: {
auto *GEPI = cast<GetElementPtrInst>(I);
return simplifyGEPInst(GEPI->getSourceElementType(), NewOps[0],
diff --git a/llvm/test/Transforms/InstSimplify/select-with-extreme-eq-cond.ll b/llvm/test/Transforms/InstSimplify/select-with-extreme-eq-cond.ll
index 0ed4453b2a0ead..3fa9468035cb7a 100644
--- a/llvm/test/Transforms/InstSimplify/select-with-extreme-eq-cond.ll
+++ b/llvm/test/Transforms/InstSimplify/select-with-extreme-eq-cond.ll
@@ -5,11 +5,8 @@ define i1 @compare_unsigned_min(i8 %0, i8 %1) {
; CHECK-LABEL: define i1 @compare_unsigned_min(
; CHECK-SAME: i8 [[TMP0:%.*]], i8 [[TMP1:%.*]]) {
; CHECK-NEXT: [[START:.*:]]
-; CHECK-NEXT: [[TMP4:%.*]] = icmp eq i8 [[TMP0]], 0
-; CHECK-NEXT: [[TMP3:%.*]] = icmp ne i8 [[TMP1]], 0
; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i8 [[TMP0]], [[TMP1]]
-; CHECK-NEXT: [[RESULT:%.*]] = select i1 [[TMP4]], i1 [[TMP3]], i1 [[TMP2]]
-; CHECK-NEXT: ret i1 [[RESULT]]
+; CHECK-NEXT: ret i1 [[TMP2]]
;
start:
%2 = icmp eq i8 %0, 0
@@ -23,11 +20,8 @@ define i1 @compare_signed_min(i8 %0, i8 %1) {
; CHECK-LABEL: define i1 @compare_signed_min(
; CHECK-SAME: i8 [[TMP0:%.*]], i8 [[TMP1:%.*]]) {
; CHECK-NEXT: [[START:.*:]]
-; CHECK-NEXT: [[TMP2:%.*]] = icmp eq i8 [[TMP0]], -128
-; CHECK-NEXT: [[TMP3:%.*]] = icmp ne i8 [[TMP1]], -128
; CHECK-NEXT: [[TMP4:%.*]] = icmp slt i8 [[TMP0]], [[TMP1]]
-; CHECK-NEXT: [[RESULT:%.*]] = select i1 [[TMP2]], i1 [[TMP3]], i1 [[TMP4]]
-; CHECK-NEXT: ret i1 [[RESULT]]
+; CHECK-NEXT: ret i1 [[TMP4]]
;
start:
%2 = icmp eq i8 %0, -128
@@ -41,11 +35,8 @@ define i1 @compare_unsigned_max(i8 %0, i8 %1) {
; CHECK-LABEL: define i1 @compare_unsigned_max(
; CHECK-SAME: i8 [[TMP0:%.*]], i8 [[TMP1:%.*]]) {
; CHECK-NEXT: [[START:.*:]]
-; CHECK-NEXT: [[TMP2:%.*]] = icmp eq i8 [[TMP0]], -1
-; CHECK-NEXT: [[TMP3:%.*]] = icmp ne i8 [[TMP1]], -1
; CHECK-NEXT: [[TMP4:%.*]] = icmp ugt i8 [[TMP0]], [[TMP1]]
-; CHECK-NEXT: [[RESULT:%.*]] = select i1 [[TMP2]], i1 [[TMP3]], i1 [[TMP4]]
-; CHECK-NEXT: ret i1 [[RESULT]]
+; CHECK-NEXT: ret i1 [[TMP4]]
;
start:
%2 = icmp eq i8 %0, 255
@@ -59,11 +50,8 @@ define i1 @compare_signed_max(i8 %0, i8 %1) {
; CHECK-LABEL: define i1 @compare_signed_max(
; CHECK-SAME: i8 [[TMP0:%.*]], i8 [[TMP1:%.*]]) {
; CHECK-NEXT: [[START:.*:]]
-; CHECK-NEXT: [[TMP2:%.*]] = icmp eq i8 [[TMP0]], 127
-; CHECK-NEXT: [[TMP3:%.*]] = icmp ne i8 [[TMP1]], 127
; CHECK-NEXT: [[TMP4:%.*]] = icmp sgt i8 [[TMP0]], [[TMP1]]
-; CHECK-NEXT: [[RESULT:%.*]] = select i1 [[TMP2]], i1 [[TMP3]], i1 [[TMP4]]
-; CHECK-NEXT: ret i1 [[RESULT]]
+; CHECK-NEXT: ret i1 [[TMP4]]
;
start:
%2 = icmp eq i8 %0, 127
@@ -77,11 +65,8 @@ define i1 @relational_cmp_unsigned_min(i8 %0, i8 %1) {
; CHECK-LABEL: define i1 @relational_cmp_unsigned_min(
; CHECK-SAME: i8 [[TMP0:%.*]], i8 [[TMP1:%.*]]) {
; CHECK-NEXT: [[START:.*:]]
-; CHECK-NEXT: [[TMP2:%.*]] = icmp eq i8 [[TMP0]], 0
-; CHECK-NEXT: [[TMP3:%.*]] = icmp ne i8 [[TMP1]], 0
; CHECK-NEXT: [[TMP4:%.*]] = icmp ult i8 [[TMP0]], [[TMP1]]
-; CHECK-NEXT: [[RESULT:%.*]] = select i1 [[TMP2]], i1 [[TMP3]], i1 [[TMP4]]
-; CHECK-NEXT: ret i1 [[RESULT]]
+; CHECK-NEXT: ret i1 [[TMP4]]
;
start:
%2 = icmp ule i8 %0, 0
@@ -95,11 +80,8 @@ define i1 @relational_cmp_signed_min(i8 %0, i8 %1) {
; CHECK-LABEL: define i1 @relational_cmp_signed_min(
; CHECK-SAME: i8 [[TMP0:%.*]], i8 [[TMP1:%.*]]) {
; CHECK-NEXT: [[START:.*:]]
-; CHECK-NEXT: [[TMP2:%.*]] = icmp eq i8 [[TMP0]], -128
-; CHECK-NEXT: [[TMP3:%.*]] = icmp ne i8 [[TMP1]], -128
; CHECK-NEXT: [[TMP4:%.*]] = icmp slt i8 [[TMP0]], [[TMP1]]
-; CHECK-NEXT: [[RESULT:%.*]] = select i1 [[TMP2]], i1 [[TMP3]], i1 [[TMP4]]
-; CHECK-NEXT: ret i1 [[RESULT]]
+; CHECK-NEXT: ret i1 [[TMP4]]
;
start:
%2 = icmp sle i8 %0, -128
@@ -113,11 +95,8 @@ define i1 @relational_cmp_unsigned_max(i8 %0, i8 %1) {
; CHECK-LABEL: define i1 @relational_cmp_unsigned_max(
; CHECK-SAME: i8 [[TMP0:%.*]], i8 [[TMP1:%.*]]) {
; CHECK-NEXT: [[START:.*:]]
-; CHECK-NEXT: [[TMP2:%.*]] = icmp eq i8 [[TMP0]], -1
-; CHECK-NEXT: [[TMP3:%.*]] = icmp ne i8 [[TMP1]], -1
; CHECK-NEXT: [[TMP4:%.*]] = icmp ugt i8 [[TMP0]], [[TMP1]]
-; CHECK-NEXT: [[RESULT:%.*]] = select i1 [[TMP2]], i1 [[TMP3]], i1 [[TMP4]]
-; CHECK-NEXT: ret i1 [[RESULT]]
+; CHECK-NEXT: ret i1 [[TMP4]]
;
start:
%2 = icmp uge i8 %0, 255
@@ -131,11 +110,8 @@ define i1 @relational_cmp_signed_max(i8 %0, i8 %1) {
; CHECK-LABEL: define i1 @relational_cmp_signed_max(
; CHECK-SAME: i8 [[TMP0:%.*]], i8 [[TMP1:%.*]]) {
; CHECK-NEXT: [[START:.*:]]
-; CHECK-NEXT: [[TMP2:%.*]] = icmp eq i8 [[TMP0]], 127
-; CHECK-NEXT: [[TMP3:%.*]] = icmp ne i8 [[TMP1]], 127
; CHECK-NEXT: [[TMP4:%.*]] = icmp sgt i8 [[TMP0]], [[TMP1]]
-; CHECK-NEXT: [[RESULT:%.*]] = select i1 [[TMP2]], i1 [[TMP3]], i1 [[TMP4]]
-; CHECK-NEXT: ret i1 [[RESULT]]
+; CHECK-NEXT: ret i1 [[TMP4]]
;
start:
%2 = icmp sge i8 %0, 127
@@ -151,12 +127,9 @@ define i1 @compare_signed_max_multiuse(i8 %0, i8 %1) {
; CHECK-LABEL: define i1 @compare_signed_max_multiuse(
; CHECK-SAME: i8 [[TMP0:%.*]], i8 [[TMP1:%.*]]) {
; CHECK-NEXT: [[START:.*:]]
-; CHECK-NEXT: [[TMP2:%.*]] = icmp eq i8 [[TMP0]], 127
-; CHECK-NEXT: [[TMP3:%.*]] = icmp ne i8 [[TMP1]], 127
; CHECK-NEXT: [[TMP4:%.*]] = icmp sgt i8 [[TMP0]], [[TMP1]]
; CHECK-NEXT: call void @use(i1 [[TMP4]])
-; CHECK-NEXT: [[RESULT:%.*]] = select i1 [[TMP2]], i1 [[TMP3]], i1 [[TMP4]]
-; CHECK-NEXT: ret i1 [[RESULT]]
+; CHECK-NEXT: ret i1 [[TMP4]]
;
start:
%2 = icmp eq i8 %0, 127
@@ -171,11 +144,8 @@ define i1 @compare_signed_min_samesign(i8 %0, i8 %1) {
; CHECK-LABEL: define i1 @compare_signed_min_samesign(
; CHECK-SAME: i8 [[TMP0:%.*]], i8 [[TMP1:%.*]]) {
; CHECK-NEXT: [[START:.*:]]
-; CHECK-NEXT: [[TMP2:%.*]] = icmp eq i8 [[TMP0]], -128
-; CHECK-NEXT: [[TMP3:%.*]] = icmp ne i8 [[TMP1]], -128
; CHECK-NEXT: [[TMP4:%.*]] = icmp samesign slt i8 [[TMP0]], [[TMP1]]
-; CHECK-NEXT: [[RESULT:%.*]] = select i1 [[TMP2]], i1 [[TMP3]], i1 [[TMP4]]
-; CHECK-NEXT: ret i1 [[RESULT]]
+; CHECK-NEXT: ret i1 [[TMP4]]
;
start:
%2 = icmp eq i8 %0, -128
@@ -189,11 +159,8 @@ define i1 @compare_flipped(i8 %0, i8 %1) {
; CHECK-LABEL: define i1 @compare_flipped(
; CHECK-SAME: i8 [[TMP0:%.*]], i8 [[TMP1:%.*]]) {
; CHECK-NEXT: [[START:.*:]]
-; CHECK-NEXT: [[TMP2:%.*]] = icmp eq i8 [[TMP0]], 0
-; CHECK-NEXT: [[TMP3:%.*]] = icmp ne i8 [[TMP1]], 0
; CHECK-NEXT: [[TMP4:%.*]] = icmp ugt i8 [[TMP1]], [[TMP0]]
-; CHECK-NEXT: [[RESULT:%.*]] = select i1 [[TMP2]], i1 [[TMP3]], i1 [[TMP4]]
-; CHECK-NEXT: ret i1 [[RESULT]]
+; CHECK-NEXT: ret i1 [[TMP4]]
;
start:
%2 = icmp eq i8 %0, 0
@@ -207,11 +174,8 @@ define i1 @compare_swapped(i8 %0, i8 %1) {
; CHECK-LABEL: define i1 @compare_swapped(
; CHECK-SAME: i8 [[TMP0:%.*]], i8 [[TMP1:%.*]]) {
; CHECK-NEXT: [[START:.*:]]
-; CHECK-NEXT: [[DOTNOT:%.*]] = icmp eq i8 [[TMP0]], 0
-; CHECK-NEXT: [[TMP2:%.*]] = icmp ne i8 [[TMP1]], 0
; CHECK-NEXT: [[RESULT:%.*]] = icmp ult i8 [[TMP0]], [[TMP1]]
-; CHECK-NEXT: [[RESULT1:%.*]] = select i1 [[DOTNOT]], i1 [[TMP2]], i1 [[RESULT]]
-; CHECK-NEXT: ret i1 [[RESULT1]]
+; CHECK-NEXT: ret i1 [[RESULT]]
;
start:
%2 = icmp ne i8 %0, 0
@@ -225,11 +189,8 @@ define i1 @compare_swapped_flipped_unsigned_max(i8 %0, i8 %1) {
; CHECK-LABEL: define i1 @compare_swapped_flipped_unsigned_max(
; CHECK-SAME: i8 [[TMP0:%.*]], i8 [[TMP1:%.*]]) {
; CHECK-NEXT: [[START:.*:]]
-; CHECK-NEXT: [[DOTNOT:%.*]] = icmp eq i8 [[TMP0]], -1
-; CHECK-NEXT: [[TMP3:%.*]] = icmp ne i8 [[TMP1]], -1
; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i8 [[TMP1]], [[TMP0]]
-; CHECK-NEXT: [[RESULT:%.*]] = select i1 [[DOTNOT]], i1 [[TMP3]], i1 [[TMP2]]
-; CHECK-NEXT: ret i1 [[RESULT]]
+; CHECK-NEXT: ret i1 [[TMP2]]
;
start:
%2 = icmp ne i8 %0, 255
@@ -243,11 +204,8 @@ define i1 @compare_unsigned_min_illegal_type(i9 %0, i9 %1) {
; CHECK-LABEL: define i1 @compare_unsigned_min_illegal_type(
; CHECK-SAME: i9 [[TMP0:%.*]], i9 [[TMP1:%.*]]) {
; CHECK-NEXT: [[START:.*:]]
-; CHECK-NEXT: [[TMP4:%.*]] = icmp eq i9 [[TMP0]], 0
-; CHECK-NEXT: [[TMP3:%.*]] = icmp ne i9 [[TMP1]], 0
; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i9 [[TMP0]], [[TMP1]]
-; CHECK-NEXT: [[RESULT:%.*]] = select i1 [[TMP4]], i1 [[TMP3]], i1 [[TMP2]]
-; CHECK-NEXT: ret i1 [[RESULT]]
+; CHECK-NEXT: ret i1 [[TMP2]]
;
start:
%2 = icmp eq i9 %0, 0
@@ -260,11 +218,8 @@ start:
define <2 x i1> @compare_vector(<2 x i8> %x, <2 x i8> %y) {
; CHECK-LABEL: define <2 x i1> @compare_vector(
; CHECK-SAME: <2 x i8> [[X:%.*]], <2 x i8> [[Y:%.*]]) {
-; CHECK-NEXT: [[TMP3:%.*]] = icmp eq <2 x i8> [[X]], zeroinitializer
-; CHECK-NEXT: [[TMP2:%.*]] = icmp ne <2 x i8> [[Y]], zeroinitializer
; CHECK-NEXT: [[TMP1:%.*]] = icmp ult <2 x i8> [[X]], [[Y]]
-; CHECK-NEXT: [[RESULT:%.*]] = select <2 x i1> [[TMP3]], <2 x i1> [[TMP2]], <2 x i1> [[TMP1]]
-; CHECK-NEXT: ret <2 x i1> [[RESULT]]
+; CHECK-NEXT: ret <2 x i1> [[TMP1]]
;
%2 = icmp eq <2 x i8> %x, <i8 0, i8 0>
%3 = icmp ne <2 x i8> %y, <i8 0, i8 0>
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