[libcxx-commits] [libcxx] [libc++] Implement C++29 Bit Permutations P3104R6 (PR #217820)

[Hristo Hristov via libcxx-commits]

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@@ -0,0 +1,32 @@
+//===----------------------------------------------------------------------===//
+//
+// 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 _LIBCPP___BIT_BIT_REVERSE_H
+#define _LIBCPP___BIT_BIT_REVERSE_H
+
+#include <__config>
+#include <__type_traits/integer_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if _LIBCPP_STD_VER >= 29
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <__unsigned_integer _Tp>
+_LIBCPP_HIDE_FROM_ABI constexpr _Tp bit_reverse(_Tp __t) noexcept {
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Zingam wrote:

These functions should be annotated with `[[nodiscard]]`. Please, read the coding guidelines and add test cases.

https://github.com/llvm/llvm-project/pull/217820