[clang] [C11] Implement WG14 N1285 (temporary lifetimes) (PR #133472)
via cfe-commits
cfe-commits at lists.llvm.org
Fri Mar 28 10:06:19 PDT 2025
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-clang
@llvm/pr-subscribers-clang-codegen
Author: Aaron Ballman (AaronBallman)
<details>
<summary>Changes</summary>
This feature largely models the same behavior as in C++11. It is technically a breaking change between C99 and C11, so the paper is not being backported to older language modes.
One difference between C++ and C is that things which are rvalues in C are often lvalues in C++ (such as the result of a ternary operator or a comma operator).
---
Patch is 21.41 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/133472.diff
8 Files Affected:
- (modified) clang/docs/ReleaseNotes.rst (+9)
- (modified) clang/lib/CodeGen/CGExpr.cpp (+2-2)
- (modified) clang/lib/Sema/Sema.cpp (+3-2)
- (modified) clang/lib/Sema/SemaInit.cpp (+1-1)
- (modified) clang/test/C/C11/n1285.c (+70-13)
- (added) clang/test/C/C11/n1285_1.c (+212)
- (modified) clang/test/CodeGenObjC/property-array-type.m (+3-2)
- (modified) clang/www/c_status.html (+1-1)
``````````diff
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index b96780cec75d9..c51b3c44f3b3b 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -160,6 +160,15 @@ C23 Feature Support
treated as if the compound literal were within the body rather than at file
scope.
+C11 Feature Support
+^^^^^^^^^^^^^^^^^^^
+- Implemented `WG14 N1285 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n1285.htm>`_
+ which introduces the notion of objects with a temporary lifetime. When an
+ expression resulting in an rvalue with structure or union type and that type
+ contains a member of array type, the expression result is an automatic storage
+ duration object with temporary lifetime which begins when the expression is
+ evaluated and ends at the evaluation of the containing full expression.
+
Non-comprehensive list of changes in this release
-------------------------------------------------
diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index 5943ff9294e1a..2328ad0def736 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -387,8 +387,8 @@ pushTemporaryCleanup(CodeGenFunction &CGF, const MaterializeTemporaryExpr *M,
if (const RecordType *RT =
E->getType()->getBaseElementTypeUnsafe()->getAs<RecordType>()) {
// Get the destructor for the reference temporary.
- auto *ClassDecl = cast<CXXRecordDecl>(RT->getDecl());
- if (!ClassDecl->hasTrivialDestructor())
+ if (auto *ClassDecl = dyn_cast<CXXRecordDecl>(RT->getDecl());
+ ClassDecl && !ClassDecl->hasTrivialDestructor())
ReferenceTemporaryDtor = ClassDecl->getDestructor();
}
diff --git a/clang/lib/Sema/Sema.cpp b/clang/lib/Sema/Sema.cpp
index 93a2d797679d4..4b573abb8efba 100644
--- a/clang/lib/Sema/Sema.cpp
+++ b/clang/lib/Sema/Sema.cpp
@@ -741,10 +741,11 @@ ExprResult Sema::ImpCastExprToType(Expr *E, QualType Ty,
if (Kind == CK_ArrayToPointerDecay) {
// C++1z [conv.array]: The temporary materialization conversion is applied.
// We also use this to fuel C++ DR1213, which applies to C++11 onwards.
- if (getLangOpts().CPlusPlus && E->isPRValue()) {
+ if ((getLangOpts().C11 || getLangOpts().CPlusPlus) && E->isPRValue()) {
// The temporary is an lvalue in C++98 and an xvalue otherwise.
ExprResult Materialized = CreateMaterializeTemporaryExpr(
- E->getType(), E, !getLangOpts().CPlusPlus11);
+ E->getType(), E,
+ getLangOpts().CPlusPlus && !getLangOpts().CPlusPlus11);
if (Materialized.isInvalid())
return ExprError();
E = Materialized.get();
diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
index 9814c3f456f0d..c47ea71cbafb5 100644
--- a/clang/lib/Sema/SemaInit.cpp
+++ b/clang/lib/Sema/SemaInit.cpp
@@ -7654,7 +7654,7 @@ ExprResult Sema::TemporaryMaterializationConversion(Expr *E) {
// FIXME: This means that AST consumers need to deal with "prvalues" that
// denote materialized temporaries. Maybe we should add another ValueKind
// for "xvalue pretending to be a prvalue" for C++98 support.
- if (!E->isPRValue() || !getLangOpts().CPlusPlus11)
+ if (!E->isPRValue() || (!getLangOpts().CPlusPlus11 && !getLangOpts().C11))
return E;
// C++1z [conv.rval]/1: T shall be a complete type.
diff --git a/clang/test/C/C11/n1285.c b/clang/test/C/C11/n1285.c
index e7a9463e68103..c4fb199e33ae5 100644
--- a/clang/test/C/C11/n1285.c
+++ b/clang/test/C/C11/n1285.c
@@ -1,24 +1,81 @@
-// RUN: %clang_cc1 -verify=wrong -std=c99 %s
-// RUN: %clang_cc1 -verify=wrong -std=c11 %s
-// RUN: %clang_cc1 -verify=cpp -std=c++11 -x c++ %s
+// RUN: %clang_cc1 -fsyntax-only -verify=good -std=c99 %s
+// RUN: %clang_cc1 -fsyntax-only -verify=expected,c -std=c11 %s
+// RUN: %clang_cc1 -fsyntax-only -verify=expected,cpp -std=c++11 -x c++ %s
-/* WG14 N1285: No
+/* WG14 N1285: Clang 21
* Extending the lifetime of temporary objects (factored approach)
*
- * NB: we do not properly materialize temporary expressions in situations where
- * it would be expected; that is why the "no-diagnostics" marking is named
- * "wrong". We do issue the expected diagnostic in C++ mode.
+ * This paper introduced the notion of an object with a temporary lifetime. Any
+ * operation resulting in an rvalue of structure or union type which contains
+ * an array results in an object with temporary lifetime.
*/
-// wrong-no-diagnostics
+// good-no-diagnostics
+
+// C11 6.2.4p8: A non-lvalue expression with structure or union type, where the
+// structure or union contains a member with array type (including,
+// recursively, members of all contained structures and unions) refers to an
+// object with automatic storage duration and temporary lifetime. Its lifetime
+// begins when the expression is evaluated and its initial value is the value
+// of the expression. Its lifetime ends when the evaluation of the containing
+// full expression or full declarator ends. Any attempt to modify an object
+// with temporary lifetime results in undefined behavior.
struct X { int a[5]; };
struct X f(void);
-int foo(void) {
- // FIXME: This diagnostic should be issued in C11 as well (though not in C99,
- // as this paper was a breaking change between C99 and C11).
- int *p = f().a; // cpp-warning {{temporary whose address is used as value of local variable 'p' will be destroyed at the end of the full-expression}}
- return *p;
+union U { int a[10]; double d; };
+union U g(void);
+
+void sink(int *);
+
+int func_return(void) {
+ int *p = f().a; // expected-warning {{temporary whose address is used as value of local variable 'p' will be destroyed at the end of the full-expression}}
+ p = f().a; // expected-warning {{object backing the pointer p will be destroyed at the end of the full-expression}}
+ p = g().a; // expected-warning {{object backing the pointer p will be destroyed at the end of the full-expression}}
+ sink(f().a); // Ok
+ return *f().a; // Ok
+}
+
+int ternary(void) {
+ int *p = (1 ? (struct X){ 0 } : f()).a; // expected-warning {{temporary whose address is used as value of local variable 'p' will be destroyed at the end of the full-expression}}
+ int *r = (1 ? (union U){ 0 } : g()).a; // expected-warning {{temporary whose address is used as value of local variable 'r' will be destroyed at the end of the full-expression}}
+ p = (1 ? (struct X){ 0 } : f()).a; // expected-warning {{object backing the pointer p will be destroyed at the end of the full-expression}}
+ sink((1 ? (struct X){ 0 } : f()).a); // Ok
+
+ // This intentionally gets one diagnostic in C and two in C++. In C, the
+ // compound literal results in an lvalue, not an rvalue as it does in C++. So
+ // only one branch results in a temporary in C but both branches do in C++.
+ int *q = 1 ? (struct X){ 0 }.a : f().a; // expected-warning {{temporary whose address is used as value of local variable 'q' will be destroyed at the end of the full-expression}} \
+ cpp-warning {{temporary whose address is used as value of local variable 'q' will be destroyed at the end of the full-expression}}
+ q = 1 ? (struct X){ 0 }.a : f().a; // expected-warning {{object backing the pointer q will be destroyed at the end of the full-expression}} \
+ cpp-warning {{object backing the pointer q will be destroyed at the end of the full-expression}}
+ q = 1 ? (struct X){ 0 }.a : g().a; // expected-warning {{object backing the pointer q will be destroyed at the end of the full-expression}} \
+ cpp-warning {{object backing the pointer q will be destroyed at the end of the full-expression}}
+ sink(1 ? (struct X){ 0 }.a : f().a); // Ok
+ return *(1 ? (struct X){ 0 }.a : f().a); // Ok
}
+int comma(void) {
+ struct X x;
+ int *p = ((void)0, x).a; // c-warning {{temporary whose address is used as value of local variable 'p' will be destroyed at the end of the full-expression}}
+ p = ((void)0, x).a; // c-warning {{object backing the pointer p will be destroyed at the end of the full-expression}}
+ sink(((void)0, x).a); // Ok
+ return *(((void)0, x).a);// Ok
+}
+
+int cast(void) {
+ struct X x;
+ int *p = ((struct X)x).a; // expected-warning {{temporary whose address is used as value of local variable 'p' will be destroyed at the end of the full-expression}}
+ p = ((struct X)x).a; // expected-warning {{object backing the pointer p will be destroyed at the end of the full-expression}}
+ sink(((struct X)x).a); // Ok
+ return *(((struct X)x).a); // Ok
+}
+
+int assign(void) {
+ struct X x, s;
+ int *p = (x = s).a; // c-warning {{temporary whose address is used as value of local variable 'p' will be destroyed at the end of the full-expression}}
+ p = (x = s).a; // c-warning {{object backing the pointer p will be destroyed at the end of the full-expression}}
+ sink((x = s).a); // Ok
+ return *((x = s).a); // Ok
+}
diff --git a/clang/test/C/C11/n1285_1.c b/clang/test/C/C11/n1285_1.c
new file mode 100644
index 0000000000000..6a3df58e5a6a0
--- /dev/null
+++ b/clang/test/C/C11/n1285_1.c
@@ -0,0 +1,212 @@
+// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py UTC_ARGS: --version 5
+// RUN: %clang_cc1 -std=c99 -Wno-dangling -emit-llvm -o - %s | FileCheck %s --check-prefix=C99
+// RUN: %clang_cc1 -std=c11 -Wno-dangling -emit-llvm -o - %s | FileCheck %s --check-prefix=C11
+
+// Ensure that codegen for temporary lifetimes makes sense.
+
+struct X { int a[5]; };
+struct X f(void);
+
+// C99-LABEL: define dso_local i32 @func_return(
+// C99-SAME: ) #[[ATTR0:[0-9]+]] {
+// C99-NEXT: [[ENTRY:.*:]]
+// C99-NEXT: [[P:%.*]] = alloca ptr, align 8
+// C99-NEXT: [[TMP:%.*]] = alloca [[STRUCT_X:%.*]], align 4
+// C99-NEXT: call void @f(ptr dead_on_unwind writable sret([[STRUCT_X]]) align 4 [[TMP]])
+// C99-NEXT: [[A:%.*]] = getelementptr inbounds nuw [[STRUCT_X]], ptr [[TMP]], i32 0, i32 0
+// C99-NEXT: [[ARRAYDECAY:%.*]] = getelementptr inbounds [5 x i32], ptr [[A]], i64 0, i64 0
+// C99-NEXT: store ptr [[ARRAYDECAY]], ptr [[P]], align 8
+// C99-NEXT: [[TMP0:%.*]] = load ptr, ptr [[P]], align 8
+// C99-NEXT: [[TMP1:%.*]] = load i32, ptr [[TMP0]], align 4
+// C99-NEXT: ret i32 [[TMP1]]
+//
+// C11-LABEL: define dso_local i32 @func_return(
+// C11-SAME: ) #[[ATTR0:[0-9]+]] {
+// C11-NEXT: [[ENTRY:.*:]]
+// C11-NEXT: [[P:%.*]] = alloca ptr, align 8
+// C11-NEXT: [[REF_TMP:%.*]] = alloca [[STRUCT_X:%.*]], align 4
+// C11-NEXT: call void @f(ptr dead_on_unwind writable sret([[STRUCT_X]]) align 4 [[REF_TMP]])
+// C11-NEXT: [[A:%.*]] = getelementptr inbounds nuw [[STRUCT_X]], ptr [[REF_TMP]], i32 0, i32 0
+// C11-NEXT: [[ARRAYDECAY:%.*]] = getelementptr inbounds [5 x i32], ptr [[A]], i64 0, i64 0
+// C11-NEXT: store ptr [[ARRAYDECAY]], ptr [[P]], align 8
+// C11-NEXT: [[TMP0:%.*]] = load ptr, ptr [[P]], align 8
+// C11-NEXT: [[TMP1:%.*]] = load i32, ptr [[TMP0]], align 4
+// C11-NEXT: ret i32 [[TMP1]]
+//
+int func_return(void) {
+ int *p = f().a;
+ return *p;
+}
+
+// C99-LABEL: define dso_local i32 @ternary(
+// C99-SAME: ) #[[ATTR0]] {
+// C99-NEXT: [[ENTRY:.*:]]
+// C99-NEXT: [[P:%.*]] = alloca ptr, align 8
+// C99-NEXT: [[TMP:%.*]] = alloca [[STRUCT_X:%.*]], align 4
+// C99-NEXT: [[Q:%.*]] = alloca ptr, align 8
+// C99-NEXT: [[DOTCOMPOUNDLITERAL:%.*]] = alloca [[STRUCT_X]], align 4
+// C99-NEXT: br i1 true, label %[[COND_TRUE:.*]], label %[[COND_FALSE:.*]]
+// C99: [[COND_TRUE]]:
+// C99-NEXT: call void @llvm.memset.p0.i64(ptr align 4 [[TMP]], i8 0, i64 20, i1 false)
+// C99-NEXT: [[A:%.*]] = getelementptr inbounds nuw [[STRUCT_X]], ptr [[TMP]], i32 0, i32 0
+// C99-NEXT: br label %[[COND_END:.*]]
+// C99: [[COND_FALSE]]:
+// C99-NEXT: call void @f(ptr dead_on_unwind writable sret([[STRUCT_X]]) align 4 [[TMP]])
+// C99-NEXT: br label %[[COND_END]]
+// C99: [[COND_END]]:
+// C99-NEXT: [[A1:%.*]] = getelementptr inbounds nuw [[STRUCT_X]], ptr [[TMP]], i32 0, i32 0
+// C99-NEXT: [[ARRAYDECAY:%.*]] = getelementptr inbounds [5 x i32], ptr [[A1]], i64 0, i64 0
+// C99-NEXT: store ptr [[ARRAYDECAY]], ptr [[P]], align 8
+// C99-NEXT: call void @llvm.memset.p0.i64(ptr align 4 [[DOTCOMPOUNDLITERAL]], i8 0, i64 20, i1 false)
+// C99-NEXT: [[A2:%.*]] = getelementptr inbounds nuw [[STRUCT_X]], ptr [[DOTCOMPOUNDLITERAL]], i32 0, i32 0
+// C99-NEXT: [[A3:%.*]] = getelementptr inbounds nuw [[STRUCT_X]], ptr [[DOTCOMPOUNDLITERAL]], i32 0, i32 0
+// C99-NEXT: [[ARRAYDECAY4:%.*]] = getelementptr inbounds [5 x i32], ptr [[A3]], i64 0, i64 0
+// C99-NEXT: store ptr [[ARRAYDECAY4]], ptr [[Q]], align 8
+// C99-NEXT: [[TMP0:%.*]] = load ptr, ptr [[P]], align 8
+// C99-NEXT: [[TMP1:%.*]] = load i32, ptr [[TMP0]], align 4
+// C99-NEXT: [[TMP2:%.*]] = load ptr, ptr [[Q]], align 8
+// C99-NEXT: [[TMP3:%.*]] = load i32, ptr [[TMP2]], align 4
+// C99-NEXT: [[ADD:%.*]] = add nsw i32 [[TMP1]], [[TMP3]]
+// C99-NEXT: ret i32 [[ADD]]
+//
+// C11-LABEL: define dso_local i32 @ternary(
+// C11-SAME: ) #[[ATTR0]] {
+// C11-NEXT: [[ENTRY:.*:]]
+// C11-NEXT: [[P:%.*]] = alloca ptr, align 8
+// C11-NEXT: [[REF_TMP:%.*]] = alloca [[STRUCT_X:%.*]], align 4
+// C11-NEXT: [[Q:%.*]] = alloca ptr, align 8
+// C11-NEXT: [[DOTCOMPOUNDLITERAL:%.*]] = alloca [[STRUCT_X]], align 4
+// C11-NEXT: br i1 true, label %[[COND_TRUE:.*]], label %[[COND_FALSE:.*]]
+// C11: [[COND_TRUE]]:
+// C11-NEXT: call void @llvm.memset.p0.i64(ptr align 4 [[REF_TMP]], i8 0, i64 20, i1 false)
+// C11-NEXT: [[A:%.*]] = getelementptr inbounds nuw [[STRUCT_X]], ptr [[REF_TMP]], i32 0, i32 0
+// C11-NEXT: br label %[[COND_END:.*]]
+// C11: [[COND_FALSE]]:
+// C11-NEXT: call void @f(ptr dead_on_unwind writable sret([[STRUCT_X]]) align 4 [[REF_TMP]])
+// C11-NEXT: br label %[[COND_END]]
+// C11: [[COND_END]]:
+// C11-NEXT: [[A1:%.*]] = getelementptr inbounds nuw [[STRUCT_X]], ptr [[REF_TMP]], i32 0, i32 0
+// C11-NEXT: [[ARRAYDECAY:%.*]] = getelementptr inbounds [5 x i32], ptr [[A1]], i64 0, i64 0
+// C11-NEXT: store ptr [[ARRAYDECAY]], ptr [[P]], align 8
+// C11-NEXT: call void @llvm.memset.p0.i64(ptr align 4 [[DOTCOMPOUNDLITERAL]], i8 0, i64 20, i1 false)
+// C11-NEXT: [[A2:%.*]] = getelementptr inbounds nuw [[STRUCT_X]], ptr [[DOTCOMPOUNDLITERAL]], i32 0, i32 0
+// C11-NEXT: [[A3:%.*]] = getelementptr inbounds nuw [[STRUCT_X]], ptr [[DOTCOMPOUNDLITERAL]], i32 0, i32 0
+// C11-NEXT: [[ARRAYDECAY4:%.*]] = getelementptr inbounds [5 x i32], ptr [[A3]], i64 0, i64 0
+// C11-NEXT: store ptr [[ARRAYDECAY4]], ptr [[Q]], align 8
+// C11-NEXT: [[TMP0:%.*]] = load ptr, ptr [[P]], align 8
+// C11-NEXT: [[TMP1:%.*]] = load i32, ptr [[TMP0]], align 4
+// C11-NEXT: [[TMP2:%.*]] = load ptr, ptr [[Q]], align 8
+// C11-NEXT: [[TMP3:%.*]] = load i32, ptr [[TMP2]], align 4
+// C11-NEXT: [[ADD:%.*]] = add nsw i32 [[TMP1]], [[TMP3]]
+// C11-NEXT: ret i32 [[ADD]]
+//
+int ternary(void) {
+ int *p;
+ p = (1 ? (struct X){ 0 } : f()).a;
+ int *q = 1 ? (struct X){ 0 }.a : f().a;
+
+ return *p + *q;
+}
+
+// C99-LABEL: define dso_local i32 @comma(
+// C99-SAME: ) #[[ATTR0]] {
+// C99-NEXT: [[ENTRY:.*:]]
+// C99-NEXT: [[X:%.*]] = alloca [[STRUCT_X:%.*]], align 4
+// C99-NEXT: [[P:%.*]] = alloca ptr, align 8
+// C99-NEXT: [[A:%.*]] = getelementptr inbounds nuw [[STRUCT_X]], ptr [[X]], i32 0, i32 0
+// C99-NEXT: [[ARRAYDECAY:%.*]] = getelementptr inbounds [5 x i32], ptr [[A]], i64 0, i64 0
+// C99-NEXT: store ptr [[ARRAYDECAY]], ptr [[P]], align 8
+// C99-NEXT: [[TMP0:%.*]] = load ptr, ptr [[P]], align 8
+// C99-NEXT: [[TMP1:%.*]] = load i32, ptr [[TMP0]], align 4
+// C99-NEXT: ret i32 [[TMP1]]
+//
+// C11-LABEL: define dso_local i32 @comma(
+// C11-SAME: ) #[[ATTR0]] {
+// C11-NEXT: [[ENTRY:.*:]]
+// C11-NEXT: [[X:%.*]] = alloca [[STRUCT_X:%.*]], align 4
+// C11-NEXT: [[P:%.*]] = alloca ptr, align 8
+// C11-NEXT: [[REF_TMP:%.*]] = alloca [[STRUCT_X]], align 4
+// C11-NEXT: call void @llvm.memcpy.p0.p0.i64(ptr align 4 [[REF_TMP]], ptr align 4 [[X]], i64 20, i1 false)
+// C11-NEXT: [[A:%.*]] = getelementptr inbounds nuw [[STRUCT_X]], ptr [[REF_TMP]], i32 0, i32 0
+// C11-NEXT: [[ARRAYDECAY:%.*]] = getelementptr inbounds [5 x i32], ptr [[A]], i64 0, i64 0
+// C11-NEXT: store ptr [[ARRAYDECAY]], ptr [[P]], align 8
+// C11-NEXT: [[TMP0:%.*]] = load ptr, ptr [[P]], align 8
+// C11-NEXT: [[TMP1:%.*]] = load i32, ptr [[TMP0]], align 4
+// C11-NEXT: ret i32 [[TMP1]]
+//
+int comma(void) {
+ struct X x;
+ int *p = ((void)0, x).a;
+ return *p;
+}
+
+// C99-LABEL: define dso_local i32 @cast(
+// C99-SAME: ) #[[ATTR0]] {
+// C99-NEXT: [[ENTRY:.*:]]
+// C99-NEXT: [[X:%.*]] = alloca [[STRUCT_X:%.*]], align 4
+// C99-NEXT: [[P:%.*]] = alloca ptr, align 8
+// C99-NEXT: [[A:%.*]] = getelementptr inbounds nuw [[STRUCT_X]], ptr [[X]], i32 0, i32 0
+// C99-NEXT: [[ARRAYDECAY:%.*]] = getelementptr inbounds [5 x i32], ptr [[A]], i64 0, i64 0
+// C99-NEXT: store ptr [[ARRAYDECAY]], ptr [[P]], align 8
+// C99-NEXT: [[TMP0:%.*]] = load ptr, ptr [[P]], align 8
+// C99-NEXT: [[TMP1:%.*]] = load i32, ptr [[TMP0]], align 4
+// C99-NEXT: ret i32 [[TMP1]]
+//
+// C11-LABEL: define dso_local i32 @cast(
+// C11-SAME: ) #[[ATTR0]] {
+// C11-NEXT: [[ENTRY:.*:]]
+// C11-NEXT: [[X:%.*]] = alloca [[STRUCT_X:%.*]], align 4
+// C11-NEXT: [[P:%.*]] = alloca ptr, align 8
+// C11-NEXT: [[REF_TMP:%.*]] = alloca [[STRUCT_X]], align 4
+// C11-NEXT: call void @llvm.memcpy.p0.p0.i64(ptr align 4 [[REF_TMP]], ptr align 4 [[X]], i64 20, i1 false)
+// C11-NEXT: [[A:%.*]] = getelementptr inbounds nuw [[STRUCT_X]], ptr [[REF_TMP]], i32 0, i32 0
+// C11-NEXT: [[ARRAYDECAY:%.*]] = getelementptr inbounds [5 x i32], ptr [[A]], i64 0, i64 0
+// C11-NEXT: store ptr [[ARRAYDECAY]], ptr [[P]], align 8
+// C11-NEXT: [[TMP0:%.*]] = load ptr, ptr [[P]], align 8
+// C11-NEXT: [[TMP1:%.*]] = load i32, ptr [[TMP0]], align 4
+// C11-NEXT: ret i32 [[TMP1]]
+//
+int cast(void) {
+ struct X x;
+ int *p;
+ p = ((struct X)x).a;
+ return *p;
+}
+
+// C99-LABEL: define dso_local i32 @assign(
+// C99-SAME: ) #[[ATTR0]] {
+// C99-NEXT: [[ENTRY:.*:]]
+// C99-NEXT: [[X:%.*]] = alloca [[STRUCT_X:%.*]], align 4
+// C99-NEXT: [[S:%.*]] = alloca [[STRUCT_X]], align 4
+// C99-NEXT: [[P:%.*]] = alloca ptr, align 8
+// C99-NEXT: [[TMP:%.*]] = alloca [[STRUCT_X]], align 4
+// C99-NEXT: call void @llvm.memcpy.p0.p0.i64(ptr align 4 [[X]], ptr align 4 [[S]], i64 20, i1 false)
+// C99-NEXT: call void @llvm.memcpy.p0.p0.i64(ptr align 4 [[TMP]], ptr align 4 [[X]], i64 20, i1 false)
+// C99-NEXT: [[A:%.*]] = getelementptr inbounds nuw [[STRUCT_X]], ptr [[TMP]], i32 0, i32 0
+// C99-NEXT: [[ARRAYDECAY:%.*]] = getelementptr inbounds [5 x i32], ptr [[A]], i64 0, i64 0
+// C99-NEXT: store ptr [[ARRAYDECAY]], ptr [[P]], align 8
+// C99-NEXT: [[TMP0:%.*]] = load ptr, ptr [[P]], align 8
+// C99-NEXT: [[TMP1:%.*]] = load i32, ptr [[TMP0]], align 4
+// C99-NEXT: ret i32 [[TMP1]]
+//
+// C11-LABEL: define dso_local i32 @assign(
+// C11-SAME: ) #[[ATTR0]] {
+// C11-NEXT: [[ENTRY:.*:]]
+// C11-NEXT: [[X:%.*]] = alloca [[STRUCT_X:%.*]], align 4
+// C11-NEXT: [[S:%.*]] = alloca [[STRUCT_X]], align 4
+// C11-NEXT: [[P:%.*]] = alloca ptr, align 8
+// C11-NEXT: [[REF_TMP:%.*]] = alloca [[STRUCT_X]], align 4
+// C11-NEXT: call void @llvm.memcpy.p0.p0.i64(ptr align 4 [[X]], ptr align 4 [[S]], i64 20, i1 false)
+// C11-NEXT: call void @llvm.memcpy.p0.p0.i64(ptr align 4 [[REF_TMP]], ptr align 4 [[X]], i64 20, i1 false)
+// C11-NEXT: [[A:%.*]] = getelementptr inbounds nuw [[STRUCT_X]], ptr [[REF_TMP]], i32 0, i32 0
+// C11-NEXT: [[ARRAYDECAY:%.*]] = getelementptr inbounds [5 x i32], ptr [[A]], i64 0, i64 0
+// C11-NEXT: store ptr [[ARRAYDECAY]], ptr [[P]], align 8
+// C11-NEXT: [[TMP0:%.*]] = load ptr, ptr [[P]], align 8
+// C11-NEXT: [[TMP1:%.*]] = load i32, ptr [[TMP0]], align 4
+// C11-NEXT: ret i32 [[TMP1]]
+//
+int assign(void) {
+ struct X x, s;
+ int *p = (x = s).a;
+ return *p;
+}
diff --git a/clang/test/CodeGenObjC/property-array-type.m b/clang/test/CodeGenObjC/property-array-type.m
index a0ad8db...
[truncated]
``````````
</details>
https://github.com/llvm/llvm-project/pull/133472
More information about the cfe-commits
mailing list