[llvm] [CGP] Fix missing sign extension for base offset in optimizeMemoryInst (PR #161377)
Vladimir Radosavljevic via llvm-commits
llvm-commits at lists.llvm.org
Fri Oct 10 03:10:48 PDT 2025
https://github.com/vladimirradosavljevic updated https://github.com/llvm/llvm-project/pull/161377
>From 926ce13aec9005dc616e27d1a8bee7ac8bb6d854 Mon Sep 17 00:00:00 2001
From: Vladimir Radosavljevic <vr at matterlabs.dev>
Date: Tue, 30 Sep 2025 15:25:58 +0200
Subject: [PATCH 1/5] [CGP] NFC: Add pre-commit test
---
.../CodeGenPrepare/X86/baseoffs-sext-bug.ll | 52 +++++++++++++++++++
1 file changed, 52 insertions(+)
create mode 100644 llvm/test/Transforms/CodeGenPrepare/X86/baseoffs-sext-bug.ll
diff --git a/llvm/test/Transforms/CodeGenPrepare/X86/baseoffs-sext-bug.ll b/llvm/test/Transforms/CodeGenPrepare/X86/baseoffs-sext-bug.ll
new file mode 100644
index 0000000000000..1ceeb492bdb03
--- /dev/null
+++ b/llvm/test/Transforms/CodeGenPrepare/X86/baseoffs-sext-bug.ll
@@ -0,0 +1,52 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 6
+; RUN: opt -S -passes='require<profile-summary>,function(codegenprepare)' < %s | FileCheck --check-prefix=GEP %s
+; RUN: opt -S -passes='require<profile-summary>,function(codegenprepare)' -addr-sink-using-gep=false < %s | FileCheck --check-prefix=NO-GEP %s
+
+target triple = "x86_64--linux-gnu"
+target datalayout = "e-m:e-p0:128:128-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
+; -p0:128:128 is added to ensure that transformation will be triggered.
+
+define i128 @test(i128 %arg) {
+; GEP-LABEL: define i128 @test(
+; GEP-SAME: i128 [[ARG:%.*]]) {
+; GEP-NEXT: [[ENTRY:.*]]:
+; GEP-NEXT: [[CMP:%.*]] = icmp ugt i128 [[ARG]], 10
+; GEP-NEXT: br i1 [[CMP]], label %[[THEN:.*]], label %[[EXIT:.*]]
+; GEP: [[THEN]]:
+; GEP-NEXT: [[SUNKADDR:%.*]] = inttoptr i128 [[ARG]] to ptr
+; GEP-NEXT: [[SUNKADDR1:%.*]] = getelementptr i8, ptr [[SUNKADDR]], i128 18446744073709551584
+; GEP-NEXT: [[LOAD:%.*]] = load i128, ptr [[SUNKADDR1]], align 16
+; GEP-NEXT: br label %[[EXIT]]
+; GEP: [[EXIT]]:
+; GEP-NEXT: [[PHI:%.*]] = phi i128 [ [[LOAD]], %[[THEN]] ], [ 0, %[[ENTRY]] ]
+; GEP-NEXT: ret i128 [[PHI]]
+;
+; NO-GEP-LABEL: define i128 @test(
+; NO-GEP-SAME: i128 [[ARG:%.*]]) {
+; NO-GEP-NEXT: [[ENTRY:.*]]:
+; NO-GEP-NEXT: [[CMP:%.*]] = icmp ugt i128 [[ARG]], 10
+; NO-GEP-NEXT: br i1 [[CMP]], label %[[THEN:.*]], label %[[EXIT:.*]]
+; NO-GEP: [[THEN]]:
+; NO-GEP-NEXT: [[SUNKADDR:%.*]] = add i128 [[ARG]], 18446744073709551584
+; NO-GEP-NEXT: [[SUNKADDR1:%.*]] = inttoptr i128 [[SUNKADDR]] to ptr
+; NO-GEP-NEXT: [[LOAD:%.*]] = load i128, ptr [[SUNKADDR1]], align 16
+; NO-GEP-NEXT: br label %[[EXIT]]
+; NO-GEP: [[EXIT]]:
+; NO-GEP-NEXT: [[PHI:%.*]] = phi i128 [ [[LOAD]], %[[THEN]] ], [ 0, %[[ENTRY]] ]
+; NO-GEP-NEXT: ret i128 [[PHI]]
+;
+entry:
+ %add = add i128 %arg, -32
+ %cmp = icmp ugt i128 %arg, 10
+ br i1 %cmp, label %then, label %exit
+
+then:
+ %inttoptr = inttoptr i128 %add to ptr
+ %load = load i128, ptr %inttoptr, align 16
+ br label %exit
+
+exit:
+ %phi = phi i128 [ %load, %then ], [ 0, %entry ]
+ ret i128 %phi
+}
+
>From a0ca124e457e18a9db3806b4a1cf0ccf68273439 Mon Sep 17 00:00:00 2001
From: Vladimir Radosavljevic <vr at matterlabs.dev>
Date: Tue, 30 Sep 2025 15:27:36 +0200
Subject: [PATCH 2/5] [CGP] Fix missing sign extension for base offset in
optimizeMemoryInst
If we have integers larger than 64-bit we need to
explicitly sign extend them, otherwise we will get
wrong zero extended values.
---
llvm/lib/CodeGen/CodeGenPrepare.cpp | 4 ++--
llvm/test/Transforms/CodeGenPrepare/X86/baseoffs-sext-bug.ll | 4 ++--
2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/llvm/lib/CodeGen/CodeGenPrepare.cpp b/llvm/lib/CodeGen/CodeGenPrepare.cpp
index eb73d01b3558c..1a68577652f52 100644
--- a/llvm/lib/CodeGen/CodeGenPrepare.cpp
+++ b/llvm/lib/CodeGen/CodeGenPrepare.cpp
@@ -6100,7 +6100,7 @@ bool CodeGenPrepare::optimizeMemoryInst(Instruction *MemoryInst, Value *Addr,
// Add in the Base Offset if present.
if (AddrMode.BaseOffs) {
- Value *V = ConstantInt::get(IntPtrTy, AddrMode.BaseOffs);
+ Value *V = ConstantInt::get(IntPtrTy, AddrMode.BaseOffs, true);
if (ResultIndex) {
// We need to add this separately from the scale above to help with
// SDAG consecutive load/store merging.
@@ -6226,7 +6226,7 @@ bool CodeGenPrepare::optimizeMemoryInst(Instruction *MemoryInst, Value *Addr,
// Add in the Base Offset if present.
if (AddrMode.BaseOffs) {
- Value *V = ConstantInt::get(IntPtrTy, AddrMode.BaseOffs);
+ Value *V = ConstantInt::get(IntPtrTy, AddrMode.BaseOffs, true);
if (Result)
Result = Builder.CreateAdd(Result, V, "sunkaddr");
else
diff --git a/llvm/test/Transforms/CodeGenPrepare/X86/baseoffs-sext-bug.ll b/llvm/test/Transforms/CodeGenPrepare/X86/baseoffs-sext-bug.ll
index 1ceeb492bdb03..a8ef80b389dac 100644
--- a/llvm/test/Transforms/CodeGenPrepare/X86/baseoffs-sext-bug.ll
+++ b/llvm/test/Transforms/CodeGenPrepare/X86/baseoffs-sext-bug.ll
@@ -14,7 +14,7 @@ define i128 @test(i128 %arg) {
; GEP-NEXT: br i1 [[CMP]], label %[[THEN:.*]], label %[[EXIT:.*]]
; GEP: [[THEN]]:
; GEP-NEXT: [[SUNKADDR:%.*]] = inttoptr i128 [[ARG]] to ptr
-; GEP-NEXT: [[SUNKADDR1:%.*]] = getelementptr i8, ptr [[SUNKADDR]], i128 18446744073709551584
+; GEP-NEXT: [[SUNKADDR1:%.*]] = getelementptr i8, ptr [[SUNKADDR]], i128 -32
; GEP-NEXT: [[LOAD:%.*]] = load i128, ptr [[SUNKADDR1]], align 16
; GEP-NEXT: br label %[[EXIT]]
; GEP: [[EXIT]]:
@@ -27,7 +27,7 @@ define i128 @test(i128 %arg) {
; NO-GEP-NEXT: [[CMP:%.*]] = icmp ugt i128 [[ARG]], 10
; NO-GEP-NEXT: br i1 [[CMP]], label %[[THEN:.*]], label %[[EXIT:.*]]
; NO-GEP: [[THEN]]:
-; NO-GEP-NEXT: [[SUNKADDR:%.*]] = add i128 [[ARG]], 18446744073709551584
+; NO-GEP-NEXT: [[SUNKADDR:%.*]] = add i128 [[ARG]], -32
; NO-GEP-NEXT: [[SUNKADDR1:%.*]] = inttoptr i128 [[SUNKADDR]] to ptr
; NO-GEP-NEXT: [[LOAD:%.*]] = load i128, ptr [[SUNKADDR1]], align 16
; NO-GEP-NEXT: br label %[[EXIT]]
>From 57216c7b10036f4cc1521dcc744aab0a30ec9381 Mon Sep 17 00:00:00 2001
From: Vladimir Radosavljevic <vr at matterlabs.dev>
Date: Fri, 10 Oct 2025 12:04:07 +0200
Subject: [PATCH 3/5] [CGP] Address comments
---
llvm/lib/CodeGen/CodeGenPrepare.cpp | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/llvm/lib/CodeGen/CodeGenPrepare.cpp b/llvm/lib/CodeGen/CodeGenPrepare.cpp
index 1a68577652f52..417917656a4bb 100644
--- a/llvm/lib/CodeGen/CodeGenPrepare.cpp
+++ b/llvm/lib/CodeGen/CodeGenPrepare.cpp
@@ -6100,7 +6100,7 @@ bool CodeGenPrepare::optimizeMemoryInst(Instruction *MemoryInst, Value *Addr,
// Add in the Base Offset if present.
if (AddrMode.BaseOffs) {
- Value *V = ConstantInt::get(IntPtrTy, AddrMode.BaseOffs, true);
+ Value *V = ConstantInt::getSigned(IntPtrTy, AddrMode.BaseOffs);
if (ResultIndex) {
// We need to add this separately from the scale above to help with
// SDAG consecutive load/store merging.
@@ -6226,7 +6226,7 @@ bool CodeGenPrepare::optimizeMemoryInst(Instruction *MemoryInst, Value *Addr,
// Add in the Base Offset if present.
if (AddrMode.BaseOffs) {
- Value *V = ConstantInt::get(IntPtrTy, AddrMode.BaseOffs, true);
+ Value *V = ConstantInt::getSigned(IntPtrTy, AddrMode.BaseOffs);
if (Result)
Result = Builder.CreateAdd(Result, V, "sunkaddr");
else
>From 68cdb30604eafe981597a3b52a0df3845b004520 Mon Sep 17 00:00:00 2001
From: Vladimir Radosavljevic <vr at matterlabs.dev>
Date: Fri, 10 Oct 2025 12:07:48 +0200
Subject: [PATCH 4/5] [CGP] NFC: Add test that exposes another issue
---
.../CodeGenPrepare/X86/baseoffs-sext-bug.ll | 29 +++++++++++++++++++
1 file changed, 29 insertions(+)
diff --git a/llvm/test/Transforms/CodeGenPrepare/X86/baseoffs-sext-bug.ll b/llvm/test/Transforms/CodeGenPrepare/X86/baseoffs-sext-bug.ll
index a8ef80b389dac..cf09845737f4b 100644
--- a/llvm/test/Transforms/CodeGenPrepare/X86/baseoffs-sext-bug.ll
+++ b/llvm/test/Transforms/CodeGenPrepare/X86/baseoffs-sext-bug.ll
@@ -50,3 +50,32 @@ exit:
ret i128 %phi
}
+define void @test_combine(ptr %ptr, i128 %arg) {
+; GEP-LABEL: define void @test_combine(
+; GEP-SAME: ptr [[PTR:%.*]], i128 [[ARG:%.*]]) {
+; GEP-NEXT: [[ENTRY:.*:]]
+; GEP-NEXT: [[CMP:%.*]] = icmp ugt i128 [[ARG]], 10
+; GEP-NEXT: [[SELECT1:%.*]] = select i1 [[CMP]], i128 18446744073709551584, i128 0
+; GEP-NEXT: [[SUNKADDR:%.*]] = getelementptr inbounds i8, ptr [[PTR]], i128 [[SELECT1]]
+; GEP-NEXT: store i128 1, ptr [[SUNKADDR]], align 16
+; GEP-NEXT: ret void
+;
+; NO-GEP-LABEL: define void @test_combine(
+; NO-GEP-SAME: ptr [[PTR:%.*]], i128 [[ARG:%.*]]) {
+; NO-GEP-NEXT: [[ENTRY:.*:]]
+; NO-GEP-NEXT: [[CMP:%.*]] = icmp ugt i128 [[ARG]], 10
+; NO-GEP-NEXT: [[SELECT1:%.*]] = select i1 [[CMP]], i128 18446744073709551584, i128 0
+; NO-GEP-NEXT: [[SUNKADDR:%.*]] = ptrtoint ptr [[PTR]] to i128
+; NO-GEP-NEXT: [[SUNKADDR2:%.*]] = add i128 [[SUNKADDR]], [[SELECT1]]
+; NO-GEP-NEXT: [[SUNKADDR3:%.*]] = inttoptr i128 [[SUNKADDR2]] to ptr
+; NO-GEP-NEXT: store i128 1, ptr [[SUNKADDR3]], align 16
+; NO-GEP-NEXT: ret void
+;
+entry:
+ %cmp = icmp ugt i128 %arg, 10
+ %gep = getelementptr inbounds i8, ptr %ptr, i128 -32
+ %select = select i1 %cmp, ptr %gep, ptr %ptr
+ store i128 1, ptr %select, align 16
+ ret void
+}
+
>From 9691142d3e1d0446a70d5859ad5b529a1ed4134f Mon Sep 17 00:00:00 2001
From: Vladimir Radosavljevic <vr at matterlabs.dev>
Date: Fri, 10 Oct 2025 12:09:47 +0200
Subject: [PATCH 5/5] [CGP] Fix issue in one more place
---
llvm/lib/CodeGen/CodeGenPrepare.cpp | 2 +-
llvm/test/Transforms/CodeGenPrepare/X86/baseoffs-sext-bug.ll | 4 ++--
2 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/llvm/lib/CodeGen/CodeGenPrepare.cpp b/llvm/lib/CodeGen/CodeGenPrepare.cpp
index 417917656a4bb..4320b1d7b1dc6 100644
--- a/llvm/lib/CodeGen/CodeGenPrepare.cpp
+++ b/llvm/lib/CodeGen/CodeGenPrepare.cpp
@@ -3194,7 +3194,7 @@ struct ExtAddrMode : public TargetLowering::AddrMode {
case ScaledRegField:
return ScaledReg;
case BaseOffsField:
- return ConstantInt::get(IntPtrTy, BaseOffs);
+ return ConstantInt::getSigned(IntPtrTy, BaseOffs);
}
}
diff --git a/llvm/test/Transforms/CodeGenPrepare/X86/baseoffs-sext-bug.ll b/llvm/test/Transforms/CodeGenPrepare/X86/baseoffs-sext-bug.ll
index cf09845737f4b..51a461e61d886 100644
--- a/llvm/test/Transforms/CodeGenPrepare/X86/baseoffs-sext-bug.ll
+++ b/llvm/test/Transforms/CodeGenPrepare/X86/baseoffs-sext-bug.ll
@@ -55,7 +55,7 @@ define void @test_combine(ptr %ptr, i128 %arg) {
; GEP-SAME: ptr [[PTR:%.*]], i128 [[ARG:%.*]]) {
; GEP-NEXT: [[ENTRY:.*:]]
; GEP-NEXT: [[CMP:%.*]] = icmp ugt i128 [[ARG]], 10
-; GEP-NEXT: [[SELECT1:%.*]] = select i1 [[CMP]], i128 18446744073709551584, i128 0
+; GEP-NEXT: [[SELECT1:%.*]] = select i1 [[CMP]], i128 -32, i128 0
; GEP-NEXT: [[SUNKADDR:%.*]] = getelementptr inbounds i8, ptr [[PTR]], i128 [[SELECT1]]
; GEP-NEXT: store i128 1, ptr [[SUNKADDR]], align 16
; GEP-NEXT: ret void
@@ -64,7 +64,7 @@ define void @test_combine(ptr %ptr, i128 %arg) {
; NO-GEP-SAME: ptr [[PTR:%.*]], i128 [[ARG:%.*]]) {
; NO-GEP-NEXT: [[ENTRY:.*:]]
; NO-GEP-NEXT: [[CMP:%.*]] = icmp ugt i128 [[ARG]], 10
-; NO-GEP-NEXT: [[SELECT1:%.*]] = select i1 [[CMP]], i128 18446744073709551584, i128 0
+; NO-GEP-NEXT: [[SELECT1:%.*]] = select i1 [[CMP]], i128 -32, i128 0
; NO-GEP-NEXT: [[SUNKADDR:%.*]] = ptrtoint ptr [[PTR]] to i128
; NO-GEP-NEXT: [[SUNKADDR2:%.*]] = add i128 [[SUNKADDR]], [[SELECT1]]
; NO-GEP-NEXT: [[SUNKADDR3:%.*]] = inttoptr i128 [[SUNKADDR2]] to ptr
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