-
Notifications
You must be signed in to change notification settings - Fork 13.5k
[libc++] LWG4169: std::atomic<T>
's default constructor should be constrained
#131950
New issue
Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.
By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.
Already on GitHub? Sign in to your account
Open
frederick-vs-ja
wants to merge
1
commit into
llvm:main
Choose a base branch
from
frederick-vs-ja:lwg-4169
base: main
Could not load branches
Branch not found: {{ refName }}
Loading
Could not load tags
Nothing to show
Loading
Are you sure you want to change the base?
Some commits from the old base branch may be removed from the timeline,
and old review comments may become outdated.
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
@llvm/pr-subscribers-libcxx Author: A. Jiang (frederick-vs-ja) ChangesDrive-by: Rename Fixes #118367. Full diff: https://github.com/llvm/llvm-project/pull/131950.diff 4 Files Affected:
diff --git a/libcxx/docs/Status/Cxx2cIssues.csv b/libcxx/docs/Status/Cxx2cIssues.csv
index 9bf31c417f3c9..66d286fd6c38c 100644
--- a/libcxx/docs/Status/Cxx2cIssues.csv
+++ b/libcxx/docs/Status/Cxx2cIssues.csv
@@ -108,7 +108,7 @@
"`LWG4154 <https://wg21.link/LWG4154>`__","The Mandates for ``std::packaged_task``'s constructor from a callable entity should consider decaying","2024-11 (Wrocław)","","",""
"`LWG4157 <https://wg21.link/LWG4157>`__","The resolution of LWG3465 was damaged by P2167R3","2024-11 (Wrocław)","","20",""
"`LWG4164 <https://wg21.link/LWG4164>`__","Missing guarantees for ``forward_list`` modifiers","2024-11 (Wrocław)","","",""
-"`LWG4169 <https://wg21.link/LWG4169>`__","``std::atomic<T>``'s default constructor should be constrained","2024-11 (Wrocław)","","",""
+"`LWG4169 <https://wg21.link/LWG4169>`__","``std::atomic<T>``'s default constructor should be constrained","2024-11 (Wrocław)","|Complete|","21",""
"`LWG4170 <https://wg21.link/LWG4170>`__","``contiguous_iterator`` should require ``to_address(I{})``","2024-11 (Wrocław)","","",""
"","","","","",""
"`LWG3578 <https://wg21.link/3578>`__","Iterator SCARYness in the context of associative container merging","2025-02 (Hagenberg)","","",""
diff --git a/libcxx/include/__atomic/atomic.h b/libcxx/include/__atomic/atomic.h
index c65f9afe4f390..0cabd4d198e66 100644
--- a/libcxx/include/__atomic/atomic.h
+++ b/libcxx/include/__atomic/atomic.h
@@ -235,7 +235,9 @@ struct atomic : public __atomic_base<_Tp> {
using __base _LIBCPP_NODEBUG = __atomic_base<_Tp>;
#if _LIBCPP_STD_VER >= 20
- _LIBCPP_HIDE_FROM_ABI atomic() = default;
+ _LIBCPP_HIDE_FROM_ABI atomic()
+ requires is_default_constructible_v<_Tp>
+ = default;
#else
_LIBCPP_HIDE_FROM_ABI atomic() _NOEXCEPT = default;
#endif
diff --git a/libcxx/test/std/atomics/atomics.types.generic/constexpr_noexcept.compile.pass.cpp b/libcxx/test/std/atomics/atomics.types.generic/constexpr_noexcept.compile.pass.cpp
deleted file mode 100644
index fca52a998eace..0000000000000
--- a/libcxx/test/std/atomics/atomics.types.generic/constexpr_noexcept.compile.pass.cpp
+++ /dev/null
@@ -1,41 +0,0 @@
-//===----------------------------------------------------------------------===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-// UNSUPPORTED: c++03, c++11, c++14, c++17
-
-#include <atomic>
-#include <type_traits>
-
-#include "test_macros.h"
-
-template <typename T>
-constexpr bool test() {
- [[maybe_unused]] constexpr T a;
- static_assert(std::is_nothrow_constructible_v<T>);
- ASSERT_NOEXCEPT(T{});
- return true;
-}
-
-struct throwing {
- throwing() {}
-};
-
-struct trivial {
- int a;
-};
-
-void test() {
- static_assert(test<std::atomic<bool>>());
- static_assert(test<std::atomic<int>>());
- static_assert(test<std::atomic<int*>>());
- static_assert(test<std::atomic<trivial>>());
- static_assert(test<std::atomic_flag>());
-
- static_assert(!std::is_nothrow_constructible_v<std::atomic<throwing>>);
- ASSERT_NOT_NOEXCEPT(std::atomic<throwing>{});
-}
diff --git a/libcxx/test/std/atomics/atomics.types.generic/default_constructor.compile.pass.cpp b/libcxx/test/std/atomics/atomics.types.generic/default_constructor.compile.pass.cpp
new file mode 100644
index 0000000000000..6d6e9e8d223a1
--- /dev/null
+++ b/libcxx/test/std/atomics/atomics.types.generic/default_constructor.compile.pass.cpp
@@ -0,0 +1,60 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include <atomic>
+#include <type_traits>
+
+#include "test_macros.h"
+
+template <typename T>
+void test() {
+#if TEST_STD_VER >= 11
+ constexpr T a{};
+ (void)a;
+# if TEST_STD_VER >= 20
+ [[maybe_unused]] constexpr T b;
+# endif
+#else
+ T a;
+ (void)a;
+#endif
+ static_assert(std::is_nothrow_constructible<T>::value, "");
+ ASSERT_NOEXCEPT(T{});
+}
+
+struct throwing {
+ throwing() {}
+};
+
+struct trivial {
+ int a;
+};
+
+struct not_default_constructible {
+ explicit not_default_constructible(int) {}
+};
+
+void test() {
+ test<std::atomic<bool> >();
+ test<std::atomic<int> >();
+ test<std::atomic<int*> >();
+ test<std::atomic<trivial> >();
+ test<std::atomic_flag>();
+
+#if TEST_STD_VER >= 20
+ static_assert(!std::is_nothrow_constructible_v<std::atomic<throwing>>);
+ ASSERT_NOT_NOEXCEPT(std::atomic<throwing>{});
+
+ static_assert(!std::is_default_constructible_v<std::atomic<not_default_constructible>>);
+#else
+ static_assert(std::is_nothrow_constructible<std::atomic<throwing> >::value, "");
+ ASSERT_NOEXCEPT(std::atomic<throwing>{});
+
+ static_assert(std::is_default_constructible<std::atomic<not_default_constructible> >::value, "");
+#endif
+}
|
3dfa2aa
to
960c240
Compare
Drive-by: Rename `constexpr_noexcept.compile.pass.cpp` to `default_constructor.compile.pass.cpp` as test coverage is added to it, and run it in all modes.
960c240
to
10d5433
Compare
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Drive-by: Rename
constexpr_noexcept.compile.pass.cpp
todefault_constructor.compile.pass.cpp
as test coverage is added to it, and compile it in all modes.Fixes #118367.