[llvm] [ValueTracking] Handle non-canonical operand order in `isImpliedCondICmps` (PR #85575)
via llvm-commits
llvm-commits at lists.llvm.org
Sun Mar 17 13:41:30 PDT 2024
https://github.com/goldsteinn updated https://github.com/llvm/llvm-project/pull/85575
>From d144e08b16b47efba096c38b2822afc897fee768 Mon Sep 17 00:00:00 2001
From: Noah Goldstein <goldstein.w.n at gmail.com>
Date: Sun, 17 Mar 2024 15:32:53 -0500
Subject: [PATCH 1/2] [ValueTracking] Add tests for implied cond with swapped
operands; NFC
---
.../icmp-select-implies-common-op.ll | 93 +++++++++++++++++++
1 file changed, 93 insertions(+)
create mode 100644 llvm/test/Transforms/InstCombine/icmp-select-implies-common-op.ll
diff --git a/llvm/test/Transforms/InstCombine/icmp-select-implies-common-op.ll b/llvm/test/Transforms/InstCombine/icmp-select-implies-common-op.ll
new file mode 100644
index 00000000000000..83850164813cb7
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/icmp-select-implies-common-op.ll
@@ -0,0 +1,93 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -S -passes=instcombine < %s | FileCheck %s
+
+define i1 @sgt_3_impliesF_eq_2(i8 %x, i8 %y) {
+; CHECK-LABEL: @sgt_3_impliesF_eq_2(
+; CHECK-NEXT: [[CMP:%.*]] = icmp sgt i8 [[X:%.*]], 3
+; CHECK-NEXT: [[SEL:%.*]] = select i1 [[CMP]], i8 2, i8 [[Y:%.*]]
+; CHECK-NEXT: [[CMP2:%.*]] = icmp eq i8 [[SEL]], [[X]]
+; CHECK-NEXT: ret i1 [[CMP2]]
+;
+ %cmp = icmp sgt i8 %x, 3
+ %sel = select i1 %cmp, i8 2, i8 %y
+ %cmp2 = icmp eq i8 %sel, %x
+ ret i1 %cmp2
+}
+
+define i1 @sgt_3_impliesT_sgt_2(i8 %x, i8 %y) {
+; CHECK-LABEL: @sgt_3_impliesT_sgt_2(
+; CHECK-NEXT: [[CMP:%.*]] = icmp sgt i8 [[X:%.*]], 3
+; CHECK-NEXT: [[SEL:%.*]] = select i1 [[CMP]], i8 2, i8 [[Y:%.*]]
+; CHECK-NEXT: [[CMP2:%.*]] = icmp sgt i8 [[SEL]], [[X]]
+; CHECK-NEXT: ret i1 [[CMP2]]
+;
+ %cmp = icmp sgt i8 %x, 3
+ %sel = select i1 %cmp, i8 2, i8 %y
+ %cmp2 = icmp sgt i8 %sel, %x
+ ret i1 %cmp2
+}
+
+define i1 @sgt_x_impliesF_eq_smin_todo(i8 %x, i8 %y, i8 %z) {
+; CHECK-LABEL: @sgt_x_impliesF_eq_smin_todo(
+; CHECK-NEXT: [[CMP:%.*]] = icmp sgt i8 [[X:%.*]], [[Z:%.*]]
+; CHECK-NEXT: [[SEL:%.*]] = select i1 [[CMP]], i8 -128, i8 [[Y:%.*]]
+; CHECK-NEXT: [[CMP2:%.*]] = icmp eq i8 [[SEL]], [[X]]
+; CHECK-NEXT: ret i1 [[CMP2]]
+;
+ %cmp = icmp sgt i8 %x, %z
+ %sel = select i1 %cmp, i8 -128, i8 %y
+ %cmp2 = icmp eq i8 %sel, %x
+ ret i1 %cmp2
+}
+
+define i1 @slt_x_impliesT_ne_smin_todo(i8 %x, i8 %y, i8 %z) {
+; CHECK-LABEL: @slt_x_impliesT_ne_smin_todo(
+; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[X:%.*]], [[Z:%.*]]
+; CHECK-NEXT: [[SEL:%.*]] = select i1 [[CMP]], i8 127, i8 [[Y:%.*]]
+; CHECK-NEXT: [[CMP2:%.*]] = icmp ne i8 [[SEL]], [[X]]
+; CHECK-NEXT: ret i1 [[CMP2]]
+;
+ %cmp = icmp slt i8 %x, %z
+ %sel = select i1 %cmp, i8 127, i8 %y
+ %cmp2 = icmp ne i8 %x, %sel
+ ret i1 %cmp2
+}
+
+define i1 @ult_x_impliesT_eq_umax_todo(i8 %x, i8 %y, i8 %z) {
+; CHECK-LABEL: @ult_x_impliesT_eq_umax_todo(
+; CHECK-NEXT: [[CMP:%.*]] = icmp ugt i8 [[Z:%.*]], [[X:%.*]]
+; CHECK-NEXT: [[SEL:%.*]] = select i1 [[CMP]], i8 -1, i8 [[Y:%.*]]
+; CHECK-NEXT: [[CMP2:%.*]] = icmp ne i8 [[SEL]], [[X]]
+; CHECK-NEXT: ret i1 [[CMP2]]
+;
+ %cmp = icmp ugt i8 %z, %x
+ %sel = select i1 %cmp, i8 255, i8 %y
+ %cmp2 = icmp ne i8 %sel, %x
+ ret i1 %cmp2
+}
+
+define i1 @ult_1_impliesF_eq_1(i8 %x, i8 %y) {
+; CHECK-LABEL: @ult_1_impliesF_eq_1(
+; CHECK-NEXT: [[CMP:%.*]] = icmp eq i8 [[SEL:%.*]], 0
+; CHECK-NEXT: [[X:%.*]] = select i1 [[CMP]], i8 1, i8 [[Y:%.*]]
+; CHECK-NEXT: [[CMP2:%.*]] = icmp eq i8 [[X]], [[SEL]]
+; CHECK-NEXT: ret i1 [[CMP2]]
+;
+ %cmp = icmp ult i8 %x, 1
+ %sel = select i1 %cmp, i8 1, i8 %y
+ %cmp2 = icmp eq i8 %x, %sel
+ ret i1 %cmp2
+}
+
+define i1 @ugt_x_impliesF_eq_umin_todo(i8 %x, i8 %y, i8 %z) {
+; CHECK-LABEL: @ugt_x_impliesF_eq_umin_todo(
+; CHECK-NEXT: [[CMP:%.*]] = icmp ugt i8 [[Z:%.*]], [[X:%.*]]
+; CHECK-NEXT: [[SEL:%.*]] = select i1 [[CMP]], i8 0, i8 [[Y:%.*]]
+; CHECK-NEXT: [[CMP2:%.*]] = icmp eq i8 [[SEL]], [[X]]
+; CHECK-NEXT: ret i1 [[CMP2]]
+;
+ %cmp = icmp ugt i8 %z, %x
+ %sel = select i1 %cmp, i8 0, i8 %y
+ %cmp2 = icmp eq i8 %x, %sel
+ ret i1 %cmp2
+}
>From e6d6d0ab1feab2814425361cb4134e6de03325e1 Mon Sep 17 00:00:00 2001
From: Noah Goldstein <goldstein.w.n at gmail.com>
Date: Sun, 17 Mar 2024 12:07:09 -0500
Subject: [PATCH 2/2] [ValueTracking] Handle non-canonical operand order in
`isImpliedCondICmps`
We don't always have canonical order here, so do it manually.
---
llvm/lib/Analysis/ValueTracking.cpp | 10 ++++++++
llvm/test/Transforms/InstCombine/assume.ll | 2 +-
.../icmp-select-implies-common-op.ll | 24 +++++++++----------
llvm/test/Transforms/InstCombine/select.ll | 6 ++---
llvm/test/Transforms/InstCombine/shift.ll | 7 +++---
5 files changed, 28 insertions(+), 21 deletions(-)
diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index edbeede910d7f7..fa0de02e63d480 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -8532,6 +8532,16 @@ static std::optional<bool> isImpliedCondICmps(const ICmpInst *LHS,
CmpInst::Predicate LPred =
LHSIsTrue ? LHS->getPredicate() : LHS->getInversePredicate();
+ // We can have non-canonical operands, so try to normalize any common operand
+ // to L0/R0.
+ if (L0 == R1) {
+ std::swap(R0, R1);
+ RPred = ICmpInst::getSwappedPredicate(RPred);
+ }
+ if (R0 == L1) {
+ std::swap(L0, L1);
+ LPred = ICmpInst::getSwappedPredicate(LPred);
+ }
// Can we infer anything when the 0-operands match and the 1-operands are
// constants (not necessarily matching)?
const APInt *LC, *RC;
diff --git a/llvm/test/Transforms/InstCombine/assume.ll b/llvm/test/Transforms/InstCombine/assume.ll
index 927f0a86b0a252..87c75fb2b55592 100644
--- a/llvm/test/Transforms/InstCombine/assume.ll
+++ b/llvm/test/Transforms/InstCombine/assume.ll
@@ -386,7 +386,7 @@ define i1 @nonnull5(ptr %a) {
define i32 @assumption_conflicts_with_known_bits(i32 %a, i32 %b) {
; CHECK-LABEL: @assumption_conflicts_with_known_bits(
; CHECK-NEXT: store i1 true, ptr poison, align 1
-; CHECK-NEXT: ret i32 1
+; CHECK-NEXT: ret i32 poison
;
%and1 = and i32 %b, 3
%B1 = lshr i32 %and1, %and1
diff --git a/llvm/test/Transforms/InstCombine/icmp-select-implies-common-op.ll b/llvm/test/Transforms/InstCombine/icmp-select-implies-common-op.ll
index 83850164813cb7..bacdb54f787d6a 100644
--- a/llvm/test/Transforms/InstCombine/icmp-select-implies-common-op.ll
+++ b/llvm/test/Transforms/InstCombine/icmp-select-implies-common-op.ll
@@ -3,10 +3,10 @@
define i1 @sgt_3_impliesF_eq_2(i8 %x, i8 %y) {
; CHECK-LABEL: @sgt_3_impliesF_eq_2(
-; CHECK-NEXT: [[CMP:%.*]] = icmp sgt i8 [[X:%.*]], 3
-; CHECK-NEXT: [[SEL:%.*]] = select i1 [[CMP]], i8 2, i8 [[Y:%.*]]
-; CHECK-NEXT: [[CMP2:%.*]] = icmp eq i8 [[SEL]], [[X]]
-; CHECK-NEXT: ret i1 [[CMP2]]
+; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[X:%.*]], 4
+; CHECK-NEXT: [[CMP2:%.*]] = icmp eq i8 [[SEL:%.*]], [[X]]
+; CHECK-NEXT: [[CMP3:%.*]] = select i1 [[CMP]], i1 [[CMP2]], i1 false
+; CHECK-NEXT: ret i1 [[CMP3]]
;
%cmp = icmp sgt i8 %x, 3
%sel = select i1 %cmp, i8 2, i8 %y
@@ -16,10 +16,10 @@ define i1 @sgt_3_impliesF_eq_2(i8 %x, i8 %y) {
define i1 @sgt_3_impliesT_sgt_2(i8 %x, i8 %y) {
; CHECK-LABEL: @sgt_3_impliesT_sgt_2(
-; CHECK-NEXT: [[CMP:%.*]] = icmp sgt i8 [[X:%.*]], 3
-; CHECK-NEXT: [[SEL:%.*]] = select i1 [[CMP]], i8 2, i8 [[Y:%.*]]
-; CHECK-NEXT: [[CMP2:%.*]] = icmp sgt i8 [[SEL]], [[X]]
-; CHECK-NEXT: ret i1 [[CMP2]]
+; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[X:%.*]], 4
+; CHECK-NEXT: [[CMP2:%.*]] = icmp sgt i8 [[SEL:%.*]], [[X]]
+; CHECK-NEXT: [[CMP3:%.*]] = select i1 [[CMP]], i1 [[CMP2]], i1 false
+; CHECK-NEXT: ret i1 [[CMP3]]
;
%cmp = icmp sgt i8 %x, 3
%sel = select i1 %cmp, i8 2, i8 %y
@@ -68,10 +68,10 @@ define i1 @ult_x_impliesT_eq_umax_todo(i8 %x, i8 %y, i8 %z) {
define i1 @ult_1_impliesF_eq_1(i8 %x, i8 %y) {
; CHECK-LABEL: @ult_1_impliesF_eq_1(
-; CHECK-NEXT: [[CMP:%.*]] = icmp eq i8 [[SEL:%.*]], 0
-; CHECK-NEXT: [[X:%.*]] = select i1 [[CMP]], i8 1, i8 [[Y:%.*]]
-; CHECK-NEXT: [[CMP2:%.*]] = icmp eq i8 [[X]], [[SEL]]
-; CHECK-NEXT: ret i1 [[CMP2]]
+; CHECK-NEXT: [[CMP:%.*]] = icmp ne i8 [[SEL:%.*]], 0
+; CHECK-NEXT: [[CMP2:%.*]] = icmp eq i8 [[X:%.*]], [[SEL]]
+; CHECK-NEXT: [[CMP3:%.*]] = select i1 [[CMP]], i1 [[CMP2]], i1 false
+; CHECK-NEXT: ret i1 [[CMP3]]
;
%cmp = icmp ult i8 %x, 1
%sel = select i1 %cmp, i8 1, i8 %y
diff --git a/llvm/test/Transforms/InstCombine/select.ll b/llvm/test/Transforms/InstCombine/select.ll
index a84904106eced4..d9734242a86891 100644
--- a/llvm/test/Transforms/InstCombine/select.ll
+++ b/llvm/test/Transforms/InstCombine/select.ll
@@ -2925,10 +2925,8 @@ define i8 @select_replacement_loop3(i32 noundef %x) {
define i16 @select_replacement_loop4(i16 noundef %p_12) {
; CHECK-LABEL: @select_replacement_loop4(
-; CHECK-NEXT: [[CMP1:%.*]] = icmp ult i16 [[P_12:%.*]], 2
-; CHECK-NEXT: [[AND1:%.*]] = and i16 [[P_12]], 1
-; CHECK-NEXT: [[AND2:%.*]] = select i1 [[CMP1]], i16 [[AND1]], i16 0
-; CHECK-NEXT: [[CMP2:%.*]] = icmp eq i16 [[AND2]], [[P_12]]
+; CHECK-NEXT: [[AND1:%.*]] = and i16 [[P_12:%.*]], 1
+; CHECK-NEXT: [[CMP2:%.*]] = icmp ult i16 [[P_12]], 2
; CHECK-NEXT: [[AND3:%.*]] = select i1 [[CMP2]], i16 [[AND1]], i16 0
; CHECK-NEXT: ret i16 [[AND3]]
;
diff --git a/llvm/test/Transforms/InstCombine/shift.ll b/llvm/test/Transforms/InstCombine/shift.ll
index 62f32c28683711..bef7fc81a7d1f9 100644
--- a/llvm/test/Transforms/InstCombine/shift.ll
+++ b/llvm/test/Transforms/InstCombine/shift.ll
@@ -1751,12 +1751,11 @@ define void @ashr_out_of_range_1(ptr %A) {
; CHECK-NEXT: [[L:%.*]] = load i177, ptr [[A:%.*]], align 4
; CHECK-NEXT: [[L_FROZEN:%.*]] = freeze i177 [[L]]
; CHECK-NEXT: [[TMP1:%.*]] = icmp eq i177 [[L_FROZEN]], -1
-; CHECK-NEXT: [[B:%.*]] = select i1 [[TMP1]], i177 0, i177 [[L_FROZEN]]
-; CHECK-NEXT: [[TMP2:%.*]] = trunc i177 [[B]] to i64
+; CHECK-NEXT: [[TMP6:%.*]] = trunc i177 [[L_FROZEN]] to i64
+; CHECK-NEXT: [[TMP2:%.*]] = select i1 [[TMP1]], i64 0, i64 [[TMP6]]
; CHECK-NEXT: [[TMP3:%.*]] = getelementptr i177, ptr [[A]], i64 [[TMP2]]
; CHECK-NEXT: [[G11:%.*]] = getelementptr i8, ptr [[TMP3]], i64 -24
-; CHECK-NEXT: [[C17:%.*]] = icmp sgt i177 [[B]], [[L_FROZEN]]
-; CHECK-NEXT: [[TMP4:%.*]] = sext i1 [[C17]] to i64
+; CHECK-NEXT: [[TMP4:%.*]] = sext i1 [[TMP1]] to i64
; CHECK-NEXT: [[G62:%.*]] = getelementptr i177, ptr [[G11]], i64 [[TMP4]]
; CHECK-NEXT: [[TMP5:%.*]] = icmp eq i177 [[L_FROZEN]], -1
; CHECK-NEXT: [[B28:%.*]] = select i1 [[TMP5]], i177 0, i177 [[L_FROZEN]]
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