https://github.com/dtcxzyw updated
https://github.com/llvm/llvm-project/pull/152575
>From 16f7036fcf78d38bc1fc05b601c9a59653eb44cf Mon Sep 17 00:00:00 2001
From: Yingwei Zheng <dtcxzyw2...@gmail.com>
Date: Fri, 8 Aug 2025 00:27:49 +0800
Subject: [PATCH 1/2] [Clang][CodeGen] Add pre-commit tests. NFC.
---
clang/test/CodeGen/pointer-arithmetic-align.c | 83 +++++++++++++++++++
1 file changed, 83 insertions(+)
create mode 100644 clang/test/CodeGen/pointer-arithmetic-align.c
diff --git a/clang/test/CodeGen/pointer-arithmetic-align.c
b/clang/test/CodeGen/pointer-arithmetic-align.c
new file mode 100644
index 0000000000000..3d3cceaaa21d0
--- /dev/null
+++ b/clang/test/CodeGen/pointer-arithmetic-align.c
@@ -0,0 +1,83 @@
+// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py
UTC_ARGS: --version 5
+// RUN: %clang_cc1 -O1 -triple=x86_64-unknown-linux %s -emit-llvm -o - |
FileCheck %s
+
+typedef unsigned char uint8_t;
+typedef unsigned long long uint64_t;
+
+struct a {
+ uint64_t b;
+ uint8_t block[16];
+};
+
+// CHECK-LABEL: define dso_local void @ptradd_0(
+// CHECK-SAME: ptr noundef writeonly captures(none) initializes((8, 9))
[[CTX:%.*]]) local_unnamed_addr #[[ATTR0:[0-9]+]] {
+// CHECK-NEXT: [[ENTRY:.*:]]
+// CHECK-NEXT: [[BLOCK:%.*]] = getelementptr inbounds nuw i8, ptr [[CTX]],
i64 8
+// CHECK-NEXT: store i8 0, ptr [[BLOCK]], align 1, !tbaa [[TBAA2:![0-9]+]]
+// CHECK-NEXT: ret void
+//
+void ptradd_0(struct a *ctx) {
+ *(ctx->block + 0) = 0;
+}
+
+// CHECK-LABEL: define dso_local void @ptradd_4(
+// CHECK-SAME: ptr noundef writeonly captures(none) initializes((12, 13))
[[CTX:%.*]]) local_unnamed_addr #[[ATTR0]] {
+// CHECK-NEXT: [[ENTRY:.*:]]
+// CHECK-NEXT: [[ADD_PTR:%.*]] = getelementptr inbounds nuw i8, ptr
[[CTX]], i64 12
+// CHECK-NEXT: store i8 0, ptr [[ADD_PTR]], align 1, !tbaa [[TBAA2]]
+// CHECK-NEXT: ret void
+//
+void ptradd_4(struct a *ctx) {
+ *(ctx->block + 4) = 0;
+}
+
+// CHECK-LABEL: define dso_local void @ptradd_8(
+// CHECK-SAME: ptr noundef writeonly captures(none) initializes((16, 17))
[[CTX:%.*]]) local_unnamed_addr #[[ATTR0]] {
+// CHECK-NEXT: [[ENTRY:.*:]]
+// CHECK-NEXT: [[ADD_PTR:%.*]] = getelementptr inbounds nuw i8, ptr
[[CTX]], i64 16
+// CHECK-NEXT: store i8 0, ptr [[ADD_PTR]], align 1, !tbaa [[TBAA2]]
+// CHECK-NEXT: ret void
+//
+void ptradd_8(struct a *ctx) {
+ *(ctx->block + 8) = 0;
+}
+
+// CHECK-LABEL: define dso_local void @ptradd_8_commuted(
+// CHECK-SAME: ptr noundef writeonly captures(none) initializes((16, 17))
[[CTX:%.*]]) local_unnamed_addr #[[ATTR0]] {
+// CHECK-NEXT: [[ENTRY:.*:]]
+// CHECK-NEXT: [[ADD_PTR:%.*]] = getelementptr inbounds nuw i8, ptr
[[CTX]], i64 16
+// CHECK-NEXT: store i8 0, ptr [[ADD_PTR]], align 1, !tbaa [[TBAA2]]
+// CHECK-NEXT: ret void
+//
+void ptradd_8_commuted(struct a *ctx) {
+ *(8 + ctx->block) = 0;
+}
+
+// CHECK-LABEL: define dso_local void @ptrsub_4(
+// CHECK-SAME: ptr noundef writeonly captures(none) initializes((8, 9))
[[CTX:%.*]]) local_unnamed_addr #[[ATTR0]] {
+// CHECK-NEXT: [[ENTRY:.*:]]
+// CHECK-NEXT: [[ADD_PTR:%.*]] = getelementptr inbounds nuw i8, ptr
[[CTX]], i64 8
+// CHECK-NEXT: store i8 0, ptr [[ADD_PTR]], align 1, !tbaa [[TBAA2]]
+// CHECK-NEXT: ret void
+//
+void ptrsub_4(struct a *ctx) {
+ *(&ctx->block[4] - 4) = 0;
+}
+
+// CHECK-LABEL: define dso_local void @neg_ptradd_var_index(
+// CHECK-SAME: ptr noundef writeonly captures(none) [[CTX:%.*]], i8 noundef
zeroext [[IDX:%.*]]) local_unnamed_addr #[[ATTR0]] {
+// CHECK-NEXT: [[ENTRY:.*:]]
+// CHECK-NEXT: [[BLOCK:%.*]] = getelementptr inbounds nuw i8, ptr [[CTX]],
i64 8
+// CHECK-NEXT: [[IDX_EXT:%.*]] = zext i8 [[IDX]] to i64
+// CHECK-NEXT: [[ADD_PTR:%.*]] = getelementptr inbounds nuw i8, ptr
[[BLOCK]], i64 [[IDX_EXT]]
+// CHECK-NEXT: store i8 0, ptr [[ADD_PTR]], align 1, !tbaa [[TBAA2]]
+// CHECK-NEXT: ret void
+//
+void neg_ptradd_var_index(struct a *ctx, uint8_t idx) {
+ *(ctx->block + idx) = 0;
+}
+//.
+// CHECK: [[TBAA2]] = !{[[META3:![0-9]+]], [[META3]], i64 0}
+// CHECK: [[META3]] = !{!"omnipotent char", [[META4:![0-9]+]], i64 0}
+// CHECK: [[META4]] = !{!"Simple C/C++ TBAA"}
+//.
>From e58f8352e60c0f541b3a8f78f3d6e5c6b3529294 Mon Sep 17 00:00:00 2001
From: Yingwei Zheng <dtcxzyw2...@gmail.com>
Date: Fri, 8 Aug 2025 21:47:36 +0800
Subject: [PATCH 2/2] [Clang][CodeGen] Preserve alignment information for
pointer arithmetics
---
clang/lib/CodeGen/CGExpr.cpp | 79 +++++++++++++++----
clang/test/CodeGen/packed-arrays.c | 6 +-
clang/test/CodeGen/pointer-arithmetic-align.c | 10 +--
.../sret_cast_with_nonzero_alloca_as.cpp | 2 +-
4 files changed, 73 insertions(+), 24 deletions(-)
diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index f1affef756df5..d71a1249ed620 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -1314,6 +1314,57 @@ void CodeGenModule::EmitExplicitCastExprType(const
ExplicitCastExpr *E,
// LValue Expression Emission
//===----------------------------------------------------------------------===//
+static CharUnits getArrayElementAlign(CharUnits arrayAlign, llvm::Value *idx,
+ CharUnits eltSize) {
+ // If we have a constant index, we can use the exact offset of the
+ // element we're accessing.
+ if (auto *constantIdx = dyn_cast<llvm::ConstantInt>(idx)) {
+ CharUnits offset = constantIdx->getZExtValue() * eltSize;
+ return arrayAlign.alignmentAtOffset(offset);
+ }
+
+ // Otherwise, use the worst-case alignment for any element.
+ return arrayAlign.alignmentOfArrayElement(eltSize);
+}
+
+/// Emit pointer + index arithmetic.
+static Address emitPointerArithmetic(CodeGenFunction &CGF,
+ const BinaryOperator *BO,
+ LValueBaseInfo *BaseInfo,
+ TBAAAccessInfo *TBAAInfo,
+ KnownNonNull_t IsKnownNonNull) {
+ assert(BO->isAdditiveOp() && "Expect an addition or subtraction.");
+ Expr *pointerOperand = BO->getLHS();
+ Expr *indexOperand = BO->getRHS();
+ bool isSubtraction = BO->getOpcode() == BO_Sub;
+
+ Address BaseAddr = Address::invalid();
+ llvm::Value *index = nullptr;
+ // In a subtraction, the LHS is always the pointer.
+ // Note: do not change the evaluation order.
+ if (!isSubtraction && !pointerOperand->getType()->isAnyPointerType()) {
+ std::swap(pointerOperand, indexOperand);
+ index = CGF.EmitScalarExpr(indexOperand);
+ BaseAddr = CGF.EmitPointerWithAlignment(pointerOperand, BaseInfo, TBAAInfo,
+ NotKnownNonNull);
+ } else {
+ BaseAddr = CGF.EmitPointerWithAlignment(pointerOperand, BaseInfo, TBAAInfo,
+ NotKnownNonNull);
+ index = CGF.EmitScalarExpr(indexOperand);
+ }
+
+ llvm::Value *pointer = BaseAddr.getBasePointer();
+ llvm::Value *Res = CGF.EmitPointerArithmetic(
+ BO, pointerOperand, pointer, indexOperand, index, isSubtraction);
+ QualType PointeeTy = BO->getType()->getPointeeType();
+ CharUnits Align =
+ getArrayElementAlign(BaseAddr.getAlignment(), index,
+ CGF.getContext().getTypeSizeInChars(PointeeTy));
+ return Address(Res, CGF.ConvertTypeForMem(PointeeTy), Align,
+ CGF.CGM.getPointerAuthInfoForPointeeType(PointeeTy),
+ /*Offset=*/nullptr, IsKnownNonNull);
+}
+
static Address EmitPointerWithAlignment(const Expr *E, LValueBaseInfo
*BaseInfo,
TBAAAccessInfo *TBAAInfo,
KnownNonNull_t IsKnownNonNull,
@@ -1376,6 +1427,13 @@ static Address EmitPointerWithAlignment(const Expr *E,
LValueBaseInfo *BaseInfo,
if (CE->getCastKind() == CK_AddressSpaceConversion)
Addr = CGF.Builder.CreateAddrSpaceCast(
Addr, CGF.ConvertType(E->getType()), ElemTy);
+ // Note: Workaround for PR114062. See also the special handling in
+ // ScalarExprEmitter::VisitCastExpr.
+ if (auto *A = dyn_cast<llvm::Argument>(Addr.getBasePointer());
+ A && A->hasStructRetAttr())
+ Addr = CGF.Builder.CreateAddrSpaceCast(
+ Addr, CGF.ConvertType(E->getType()), ElemTy);
+
return CGF.authPointerToPointerCast(Addr, CE->getSubExpr()->getType(),
CE->getType());
}
@@ -1436,6 +1494,12 @@ static Address EmitPointerWithAlignment(const Expr *E,
LValueBaseInfo *BaseInfo,
}
}
+ // Pointer arithmetic: pointer +/- index.
+ if (auto *BO = dyn_cast<BinaryOperator>(E)) {
+ if (BO->isAdditiveOp())
+ return emitPointerArithmetic(CGF, BO, BaseInfo, TBAAInfo,
IsKnownNonNull);
+ }
+
// TODO: conditional operators, comma.
// Otherwise, use the alignment of the type.
@@ -4222,21 +4286,6 @@ static Address emitArraySubscriptGEP(CodeGenFunction
&CGF, Address addr,
}
}
-static CharUnits getArrayElementAlign(CharUnits arrayAlign,
- llvm::Value *idx,
- CharUnits eltSize) {
- // If we have a constant index, we can use the exact offset of the
- // element we're accessing.
- if (auto constantIdx = dyn_cast<llvm::ConstantInt>(idx)) {
- CharUnits offset = constantIdx->getZExtValue() * eltSize;
- return arrayAlign.alignmentAtOffset(offset);
-
- // Otherwise, use the worst-case alignment for any element.
- } else {
- return arrayAlign.alignmentOfArrayElement(eltSize);
- }
-}
-
static QualType getFixedSizeElementType(const ASTContext &ctx,
const VariableArrayType *vla) {
QualType eltType;
diff --git a/clang/test/CodeGen/packed-arrays.c
b/clang/test/CodeGen/packed-arrays.c
index 097fa7fc0feb7..51629b66d0687 100644
--- a/clang/test/CodeGen/packed-arrays.c
+++ b/clang/test/CodeGen/packed-arrays.c
@@ -55,7 +55,7 @@ int align3_x0 = __alignof(((struct s3*) 0)->x[0]);
// CHECK: load i32, ptr %{{.*}}, align 1
// CHECK: }
// CHECK-LABEL: define{{.*}} i32 @f0_b
-// CHECK: load i32, ptr %{{.*}}, align 4
+// CHECK: load i32, ptr %{{.*}}, align 1
// CHECK: }
int f0_a(struct s0 *a) {
return a->x[1];
@@ -100,7 +100,7 @@ int f1_d(struct s1 *a) {
// CHECK: load i32, ptr %{{.*}}, align 1
// CHECK: }
// CHECK-LABEL: define{{.*}} i32 @f2_b
-// CHECK: load i32, ptr %{{.*}}, align 4
+// CHECK: load i32, ptr %{{.*}}, align 1
// CHECK: }
// CHECK-LABEL: define{{.*}} i32 @f2_c
// CHECK: load i32, ptr %{{.*}}, align 1
@@ -125,7 +125,7 @@ int f2_d(struct s2 *a) {
// CHECK: load i32, ptr %{{.*}}, align 1
// CHECK: }
// CHECK-LABEL: define{{.*}} i32 @f3_b
-// CHECK: load i32, ptr %{{.*}}, align 4
+// CHECK: load i32, ptr %{{.*}}, align 1
// CHECK: }
// CHECK-LABEL: define{{.*}} i32 @f3_c
// CHECK: load i32, ptr %{{.*}}, align 1
diff --git a/clang/test/CodeGen/pointer-arithmetic-align.c
b/clang/test/CodeGen/pointer-arithmetic-align.c
index 3d3cceaaa21d0..745ab84635c1b 100644
--- a/clang/test/CodeGen/pointer-arithmetic-align.c
+++ b/clang/test/CodeGen/pointer-arithmetic-align.c
@@ -13,7 +13,7 @@ struct a {
// CHECK-SAME: ptr noundef writeonly captures(none) initializes((8, 9))
[[CTX:%.*]]) local_unnamed_addr #[[ATTR0:[0-9]+]] {
// CHECK-NEXT: [[ENTRY:.*:]]
// CHECK-NEXT: [[BLOCK:%.*]] = getelementptr inbounds nuw i8, ptr [[CTX]],
i64 8
-// CHECK-NEXT: store i8 0, ptr [[BLOCK]], align 1, !tbaa [[TBAA2:![0-9]+]]
+// CHECK-NEXT: store i8 0, ptr [[BLOCK]], align 8, !tbaa [[TBAA2:![0-9]+]]
// CHECK-NEXT: ret void
//
void ptradd_0(struct a *ctx) {
@@ -24,7 +24,7 @@ void ptradd_0(struct a *ctx) {
// CHECK-SAME: ptr noundef writeonly captures(none) initializes((12, 13))
[[CTX:%.*]]) local_unnamed_addr #[[ATTR0]] {
// CHECK-NEXT: [[ENTRY:.*:]]
// CHECK-NEXT: [[ADD_PTR:%.*]] = getelementptr inbounds nuw i8, ptr
[[CTX]], i64 12
-// CHECK-NEXT: store i8 0, ptr [[ADD_PTR]], align 1, !tbaa [[TBAA2]]
+// CHECK-NEXT: store i8 0, ptr [[ADD_PTR]], align 4, !tbaa [[TBAA2]]
// CHECK-NEXT: ret void
//
void ptradd_4(struct a *ctx) {
@@ -35,7 +35,7 @@ void ptradd_4(struct a *ctx) {
// CHECK-SAME: ptr noundef writeonly captures(none) initializes((16, 17))
[[CTX:%.*]]) local_unnamed_addr #[[ATTR0]] {
// CHECK-NEXT: [[ENTRY:.*:]]
// CHECK-NEXT: [[ADD_PTR:%.*]] = getelementptr inbounds nuw i8, ptr
[[CTX]], i64 16
-// CHECK-NEXT: store i8 0, ptr [[ADD_PTR]], align 1, !tbaa [[TBAA2]]
+// CHECK-NEXT: store i8 0, ptr [[ADD_PTR]], align 8, !tbaa [[TBAA2]]
// CHECK-NEXT: ret void
//
void ptradd_8(struct a *ctx) {
@@ -46,7 +46,7 @@ void ptradd_8(struct a *ctx) {
// CHECK-SAME: ptr noundef writeonly captures(none) initializes((16, 17))
[[CTX:%.*]]) local_unnamed_addr #[[ATTR0]] {
// CHECK-NEXT: [[ENTRY:.*:]]
// CHECK-NEXT: [[ADD_PTR:%.*]] = getelementptr inbounds nuw i8, ptr
[[CTX]], i64 16
-// CHECK-NEXT: store i8 0, ptr [[ADD_PTR]], align 1, !tbaa [[TBAA2]]
+// CHECK-NEXT: store i8 0, ptr [[ADD_PTR]], align 8, !tbaa [[TBAA2]]
// CHECK-NEXT: ret void
//
void ptradd_8_commuted(struct a *ctx) {
@@ -57,7 +57,7 @@ void ptradd_8_commuted(struct a *ctx) {
// CHECK-SAME: ptr noundef writeonly captures(none) initializes((8, 9))
[[CTX:%.*]]) local_unnamed_addr #[[ATTR0]] {
// CHECK-NEXT: [[ENTRY:.*:]]
// CHECK-NEXT: [[ADD_PTR:%.*]] = getelementptr inbounds nuw i8, ptr
[[CTX]], i64 8
-// CHECK-NEXT: store i8 0, ptr [[ADD_PTR]], align 1, !tbaa [[TBAA2]]
+// CHECK-NEXT: store i8 0, ptr [[ADD_PTR]], align 4, !tbaa [[TBAA2]]
// CHECK-NEXT: ret void
//
void ptrsub_4(struct a *ctx) {
diff --git a/clang/test/CodeGenCXX/sret_cast_with_nonzero_alloca_as.cpp
b/clang/test/CodeGenCXX/sret_cast_with_nonzero_alloca_as.cpp
index 320c712b665de..712aa69063382 100644
--- a/clang/test/CodeGenCXX/sret_cast_with_nonzero_alloca_as.cpp
+++ b/clang/test/CodeGenCXX/sret_cast_with_nonzero_alloca_as.cpp
@@ -19,7 +19,7 @@ struct X { int z[17]; };
// CHECK-NEXT: [[TMP1:%.*]] = load i8, ptr [[Y_ADDR_ASCAST]], align 1
// CHECK-NEXT: [[AGG_RESULT_ASCAST1:%.*]] = addrspacecast ptr addrspace(5)
[[AGG_RESULT]] to ptr
// CHECK-NEXT: [[ADD_PTR2:%.*]] = getelementptr inbounds i8, ptr
[[AGG_RESULT_ASCAST1]], i64 2
-// CHECK-NEXT: store i8 [[TMP1]], ptr [[ADD_PTR2]], align 1
+// CHECK-NEXT: store i8 [[TMP1]], ptr [[ADD_PTR2]], align 2
// CHECK-NEXT: ret void
//
X foo(char x, char y) {
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