[llvm] [ConstraintElim] Decompose sext-like insts for signed predicates (PR #82344)
Yingwei Zheng via llvm-commits
llvm-commits at lists.llvm.org
Thu Feb 22 08:29:41 PST 2024
https://github.com/dtcxzyw updated https://github.com/llvm/llvm-project/pull/82344
>From 5c3ddf94f731333484e327c32cbc12e78a6deea8 Mon Sep 17 00:00:00 2001
From: Yingwei Zheng <dtcxzyw2333 at gmail.com>
Date: Fri, 23 Feb 2024 00:20:43 +0800
Subject: [PATCH 1/2] [ConstraintElim] Fix pre-commit tests in #82357. NFC.
---
.../Transforms/ConstraintElimination/sext.ll | 74 ++++++++++++++-----
1 file changed, 54 insertions(+), 20 deletions(-)
diff --git a/llvm/test/Transforms/ConstraintElimination/sext.ll b/llvm/test/Transforms/ConstraintElimination/sext.ll
index ed8dd502b6ef9d..aefb3656397bb2 100644
--- a/llvm/test/Transforms/ConstraintElimination/sext.ll
+++ b/llvm/test/Transforms/ConstraintElimination/sext.ll
@@ -31,33 +31,33 @@ else:
ret i1 false
}
-define i1 @cmp_sext_positive_increment(i32 %a, i32 %b, i64 %c){
-; CHECK-LABEL: define i1 @cmp_sext_positive_increment(
-; CHECK-SAME: i32 [[A:%.*]], i32 [[B:%.*]], i64 [[C:%.*]]) {
+define i1 @cmp_sext_add(i32 %a, i32 %b){
+; CHECK-LABEL: define i1 @cmp_sext_add(
+; CHECK-SAME: i32 [[A:%.*]], i32 [[B:%.*]]) {
; CHECK-NEXT: entry:
-; CHECK-NEXT: [[POS:%.*]] = icmp sgt i64 [[C]], 0
-; CHECK-NEXT: call void @llvm.assume(i1 [[POS]])
; CHECK-NEXT: [[CMP:%.*]] = icmp slt i32 [[A]], [[B]]
; CHECK-NEXT: br i1 [[CMP]], label [[THEN:%.*]], label [[ELSE:%.*]]
; CHECK: then:
-; CHECK-NEXT: [[SA:%.*]] = sext i32 [[A]] to i64
-; CHECK-NEXT: [[SB:%.*]] = sext i32 [[B]] to i64
-; CHECK-NEXT: [[ADD:%.*]] = add nsw i64 [[SA]], [[C]]
+; CHECK-NEXT: [[A1:%.*]] = add nsw i32 [[A]], 1
+; CHECK-NEXT: [[B1:%.*]] = add nsw i32 [[B]], 1
+; CHECK-NEXT: [[SA:%.*]] = sext i32 [[A1]] to i64
+; CHECK-NEXT: [[SB:%.*]] = sext i32 [[B1]] to i64
+; CHECK-NEXT: [[ADD:%.*]] = add nsw i64 [[SA]], 1
; CHECK-NEXT: [[CMP2:%.*]] = icmp sge i64 [[SB]], [[ADD]]
; CHECK-NEXT: ret i1 [[CMP2]]
; CHECK: else:
; CHECK-NEXT: ret i1 false
;
entry:
- %pos = icmp sgt i64 %c, 0
- call void @llvm.assume(i1 %pos)
%cmp = icmp slt i32 %a, %b
br i1 %cmp, label %then, label %else
then:
- %sa = sext i32 %a to i64
- %sb = sext i32 %b to i64
- %add = add nsw i64 %sa, %c
+ %a1 = add nsw i32 %a, 1
+ %b1 = add nsw i32 %b, 1
+ %sa = sext i32 %a1 to i64
+ %sb = sext i32 %b1 to i64
+ %add = add nsw i64 %sa, 1
%cmp2 = icmp sge i64 %sb, %add
ret i1 %cmp2
@@ -65,30 +65,34 @@ else:
ret i1 false
}
-define i1 @cmp_sext_sgt(i32 %a, i32 %b){
-; CHECK-LABEL: define i1 @cmp_sext_sgt(
-; CHECK-SAME: i32 [[A:%.*]], i32 [[B:%.*]]) {
+define i1 @cmp_sext_dynamic_increment(i32 %a, i32 %b, i64 %c){
+; CHECK-LABEL: define i1 @cmp_sext_dynamic_increment(
+; CHECK-SAME: i32 [[A:%.*]], i32 [[B:%.*]], i64 [[C:%.*]]) {
; CHECK-NEXT: entry:
+; CHECK-NEXT: [[POS:%.*]] = icmp slt i64 [[C]], 2
+; CHECK-NEXT: call void @llvm.assume(i1 [[POS]])
; CHECK-NEXT: [[CMP:%.*]] = icmp slt i32 [[A]], [[B]]
; CHECK-NEXT: br i1 [[CMP]], label [[THEN:%.*]], label [[ELSE:%.*]]
; CHECK: then:
; CHECK-NEXT: [[SA:%.*]] = sext i32 [[A]] to i64
; CHECK-NEXT: [[SB:%.*]] = sext i32 [[B]] to i64
-; CHECK-NEXT: [[ADD:%.*]] = add nsw i64 [[SA]], 1
-; CHECK-NEXT: [[CMP2:%.*]] = icmp sgt i64 [[SB]], [[ADD]]
+; CHECK-NEXT: [[ADD:%.*]] = add nsw i64 [[SA]], [[C]]
+; CHECK-NEXT: [[CMP2:%.*]] = icmp sge i64 [[SB]], [[ADD]]
; CHECK-NEXT: ret i1 [[CMP2]]
; CHECK: else:
; CHECK-NEXT: ret i1 false
;
entry:
+ %pos = icmp slt i64 %c, 2
+ call void @llvm.assume(i1 %pos)
%cmp = icmp slt i32 %a, %b
br i1 %cmp, label %then, label %else
then:
%sa = sext i32 %a to i64
%sb = sext i32 %b to i64
- %add = add nsw i64 %sa, 1
- %cmp2 = icmp sgt i64 %sb, %add
+ %add = add nsw i64 %sa, %c
+ %cmp2 = icmp sge i64 %sb, %add
ret i1 %cmp2
else:
@@ -216,3 +220,33 @@ then:
else:
ret i1 false
}
+
+define i1 @cmp_sext_sgt(i32 %a, i32 %b){
+; CHECK-LABEL: define i1 @cmp_sext_sgt(
+; CHECK-SAME: i32 [[A:%.*]], i32 [[B:%.*]]) {
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[CMP:%.*]] = icmp slt i32 [[A]], [[B]]
+; CHECK-NEXT: br i1 [[CMP]], label [[THEN:%.*]], label [[ELSE:%.*]]
+; CHECK: then:
+; CHECK-NEXT: [[SA:%.*]] = sext i32 [[A]] to i64
+; CHECK-NEXT: [[SB:%.*]] = sext i32 [[B]] to i64
+; CHECK-NEXT: [[ADD:%.*]] = add nsw i64 [[SA]], 1
+; CHECK-NEXT: [[CMP2:%.*]] = icmp sgt i64 [[SB]], [[ADD]]
+; CHECK-NEXT: ret i1 [[CMP2]]
+; CHECK: else:
+; CHECK-NEXT: ret i1 false
+;
+entry:
+ %cmp = icmp slt i32 %a, %b
+ br i1 %cmp, label %then, label %else
+
+then:
+ %sa = sext i32 %a to i64
+ %sb = sext i32 %b to i64
+ %add = add nsw i64 %sa, 1
+ %cmp2 = icmp sgt i64 %sb, %add
+ ret i1 %cmp2
+
+else:
+ ret i1 false
+}
>From d3a709e7cc4da513b50129df146d7a2cdc19c2b2 Mon Sep 17 00:00:00 2001
From: Yingwei Zheng <dtcxzyw2333 at gmail.com>
Date: Fri, 23 Feb 2024 00:21:24 +0800
Subject: [PATCH 2/2] [ConstraintElim] Decompose sext-like insts for signed
predicates
---
.../lib/Transforms/Scalar/ConstraintElimination.cpp | 13 +++++++++++--
.../test/Transforms/ConstraintElimination/minmax.ll | 9 +++------
llvm/test/Transforms/ConstraintElimination/sext.ll | 12 ++++--------
3 files changed, 18 insertions(+), 16 deletions(-)
diff --git a/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp b/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
index db05c63f388fb1..9b6a39e98f5ce8 100644
--- a/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
+++ b/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
@@ -499,6 +499,8 @@ static Decomposition decompose(Value *V,
if (!Ty->isIntegerTy() || Ty->getIntegerBitWidth() > 64)
return V;
+ bool IsKnownNonNegative = false;
+
// Decompose \p V used with a signed predicate.
if (IsSigned) {
if (auto *CI = dyn_cast<ConstantInt>(V)) {
@@ -507,6 +509,14 @@ static Decomposition decompose(Value *V,
}
Value *Op0;
Value *Op1;
+
+ if (match(V, m_SExt(m_Value(Op0))))
+ V = Op0;
+ else if (match(V, m_NNegZExt(m_Value(Op0)))) {
+ V = Op0;
+ IsKnownNonNegative = true;
+ }
+
if (match(V, m_NSWAdd(m_Value(Op0), m_Value(Op1))))
return MergeResults(Op0, Op1, IsSigned);
@@ -529,7 +539,7 @@ static Decomposition decompose(Value *V,
}
}
- return V;
+ return {V, IsKnownNonNegative};
}
if (auto *CI = dyn_cast<ConstantInt>(V)) {
@@ -539,7 +549,6 @@ static Decomposition decompose(Value *V,
}
Value *Op0;
- bool IsKnownNonNegative = false;
if (match(V, m_ZExt(m_Value(Op0)))) {
IsKnownNonNegative = true;
V = Op0;
diff --git a/llvm/test/Transforms/ConstraintElimination/minmax.ll b/llvm/test/Transforms/ConstraintElimination/minmax.ll
index ab3e9f381245be..029b6508a2106e 100644
--- a/llvm/test/Transforms/ConstraintElimination/minmax.ll
+++ b/llvm/test/Transforms/ConstraintElimination/minmax.ll
@@ -611,8 +611,7 @@ define i64 @pr82271(i32 %a, i32 %b){
; CHECK-NEXT: [[SA:%.*]] = sext i32 [[A]] to i64
; CHECK-NEXT: [[SB:%.*]] = sext i32 [[B]] to i64
; CHECK-NEXT: [[ADD:%.*]] = add nsw i64 [[SA]], 1
-; CHECK-NEXT: [[SMAX:%.*]] = call i64 @llvm.smax.i64(i64 [[SB]], i64 [[ADD]])
-; CHECK-NEXT: ret i64 [[SMAX]]
+; CHECK-NEXT: ret i64 [[SB]]
; CHECK: else:
; CHECK-NEXT: ret i64 0
;
@@ -641,8 +640,7 @@ define i64 @pr82271_sext_zext_nneg(i32 %a, i32 %b){
; CHECK-NEXT: [[SA:%.*]] = sext i32 [[A]] to i64
; CHECK-NEXT: [[SB:%.*]] = zext nneg i32 [[B]] to i64
; CHECK-NEXT: [[ADD:%.*]] = add nsw i64 [[SA]], 1
-; CHECK-NEXT: [[SMAX:%.*]] = call i64 @llvm.smax.i64(i64 [[SB]], i64 [[ADD]])
-; CHECK-NEXT: ret i64 [[SMAX]]
+; CHECK-NEXT: ret i64 [[SB]]
; CHECK: else:
; CHECK-NEXT: ret i64 0
;
@@ -671,8 +669,7 @@ define i64 @pr82271_zext_nneg(i32 %a, i32 %b){
; CHECK-NEXT: [[SA:%.*]] = zext nneg i32 [[A]] to i64
; CHECK-NEXT: [[SB:%.*]] = zext nneg i32 [[B]] to i64
; CHECK-NEXT: [[ADD:%.*]] = add nsw i64 [[SA]], 1
-; CHECK-NEXT: [[SMAX:%.*]] = call i64 @llvm.smax.i64(i64 [[SB]], i64 [[ADD]])
-; CHECK-NEXT: ret i64 [[SMAX]]
+; CHECK-NEXT: ret i64 [[SB]]
; CHECK: else:
; CHECK-NEXT: ret i64 0
;
diff --git a/llvm/test/Transforms/ConstraintElimination/sext.ll b/llvm/test/Transforms/ConstraintElimination/sext.ll
index aefb3656397bb2..5a8a37d0d57035 100644
--- a/llvm/test/Transforms/ConstraintElimination/sext.ll
+++ b/llvm/test/Transforms/ConstraintElimination/sext.ll
@@ -11,8 +11,7 @@ define i1 @cmp_sext(i32 %a, i32 %b){
; CHECK-NEXT: [[SA:%.*]] = sext i32 [[A]] to i64
; CHECK-NEXT: [[SB:%.*]] = sext i32 [[B]] to i64
; CHECK-NEXT: [[ADD:%.*]] = add nsw i64 [[SA]], 1
-; CHECK-NEXT: [[CMP2:%.*]] = icmp sge i64 [[SB]], [[ADD]]
-; CHECK-NEXT: ret i1 [[CMP2]]
+; CHECK-NEXT: ret i1 true
; CHECK: else:
; CHECK-NEXT: ret i1 false
;
@@ -43,8 +42,7 @@ define i1 @cmp_sext_add(i32 %a, i32 %b){
; CHECK-NEXT: [[SA:%.*]] = sext i32 [[A1]] to i64
; CHECK-NEXT: [[SB:%.*]] = sext i32 [[B1]] to i64
; CHECK-NEXT: [[ADD:%.*]] = add nsw i64 [[SA]], 1
-; CHECK-NEXT: [[CMP2:%.*]] = icmp sge i64 [[SB]], [[ADD]]
-; CHECK-NEXT: ret i1 [[CMP2]]
+; CHECK-NEXT: ret i1 true
; CHECK: else:
; CHECK-NEXT: ret i1 false
;
@@ -77,8 +75,7 @@ define i1 @cmp_sext_dynamic_increment(i32 %a, i32 %b, i64 %c){
; CHECK-NEXT: [[SA:%.*]] = sext i32 [[A]] to i64
; CHECK-NEXT: [[SB:%.*]] = sext i32 [[B]] to i64
; CHECK-NEXT: [[ADD:%.*]] = add nsw i64 [[SA]], [[C]]
-; CHECK-NEXT: [[CMP2:%.*]] = icmp sge i64 [[SB]], [[ADD]]
-; CHECK-NEXT: ret i1 [[CMP2]]
+; CHECK-NEXT: ret i1 true
; CHECK: else:
; CHECK-NEXT: ret i1 false
;
@@ -109,8 +106,7 @@ define i1 @cmp_zext_nneg(i32 %a, i32 %b){
; CHECK-NEXT: [[SA:%.*]] = zext nneg i32 [[A]] to i64
; CHECK-NEXT: [[SB:%.*]] = zext nneg i32 [[B]] to i64
; CHECK-NEXT: [[ADD:%.*]] = add nsw i64 [[SA]], 1
-; CHECK-NEXT: [[CMP2:%.*]] = icmp sge i64 [[SB]], [[ADD]]
-; CHECK-NEXT: ret i1 [[CMP2]]
+; CHECK-NEXT: ret i1 true
; CHECK: else:
; CHECK-NEXT: ret i1 false
;
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