[libc-commits] [libc] [libc] fix atomic and apply an explicit check on unique object representations (PR #119715)

[Nick Desaulniers via libc-commits]

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@@ -0,0 +1,28 @@
+//===-- has_unique_object_representations type_traits ------------*- C++-*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+#ifndef LLVM_LIBC_SRC___SUPPORT_CPP_TYPE_TRAITS_HAS_UNIQUE_OBJECT_REPRESENTATIONS_H
+#define LLVM_LIBC_SRC___SUPPORT_CPP_TYPE_TRAITS_HAS_UNIQUE_OBJECT_REPRESENTATIONS_H
+
+#include "src/__support/CPP/type_traits/integral_constant.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+namespace cpp {
+
+template <class T>
+struct has_unique_object_representations
+    : public integral_constant<bool, __has_unique_object_representations(T)> {};
+
+template <class T>
+LIBC_INLINE_VAR constexpr bool has_unique_object_representations_v =
+    has_unique_object_representations<T>::value;
+
+} // namespace cpp
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC___SUPPORT_CPP_TYPE_TRAITS_HAS_UNIQUE_OBJECT_REPRESENTATIONS_H
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nickdesaulniers wrote:

Probably worth adding a unit test for this to libc/test/src/__support/CPP/type_traits_test.cpp?

https://github.com/llvm/llvm-project/pull/119715