[libcxx-commits] [libcxx] [libc++][In progress] Floating Point Atomic (PR #67799)

[Louis Dionne via libcxx-commits]

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@@ -0,0 +1,39 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+
+// constexpr atomic() noexcept;
+// constexpr atomic(floating-point-type) noexcept;
+
+#include <atomic>
+#include <cassert>
+#include <concepts>
+
+#include "test_macros.h"
+
+template <class T>
+void test() {
+  // constexpr atomic() noexcept;
+  {
+    constexpr std::atomic<T> a = {};
+    assert(a.load() == T(0));
+  }
+
+  // constexpr atomic(floating-point-type) noexcept;
+  {
+    constexpr std::atomic<T> a = T(5.2);
+    assert(a.load() == T(5.2));
+  }
+}
+
+int main(int, char**) {
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ldionne wrote:

I think the rationale for `atomic`'s constructors being `constexpr` (but no other members) is so that we can `constinit` variables of that type. We should test that as well.

https://github.com/llvm/llvm-project/pull/67799