[libcxx-commits] [libcxx] [libc++][math] Add `constexpr` for `std::signbit()` (PR #105946)

[Hristo Hristov via libcxx-commits]

================
@@ -0,0 +1,78 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// bool signbit(floating-point-type x); // constexpr since C++23
+
+// We don't control the implementation on windows
+// UNSUPPORTED: windows
+
+// These compilers don't support constexpr `__builtin_signbit` yet.
+// UNSUPPORTED: clang-17, clang-18, clang-19, apple-clang-16, apple-clang-17, apple-clang-18
----------------
Zingam wrote:

> Got it. Thanks. In this case, wouldn't it be better to remove `apple-clang-16` from the list of unsupported compiler?

The non-buildkite CI jobs seem to use Apple Clang 16:
https://github.com/llvm/llvm-project/actions/runs/10705674588/job/29687013778?pr=105946#step:5:84

Also upcoming XCode 16 is based on AppleClang 17.

https://github.com/llvm/llvm-project/pull/105946