llvm-project/libcxx/include/__bit/has_single_bit.h
Nikolas Klauser 3c56437eaf
[libc++] Refactor signed/unsigned integer traits (#142750)
This patch does a few things:
- `__libcpp_is_signed_integer` and `__libcpp_is_unsigned_integer` are
refactored to be variable templates instead of class templates.
- the two traits are merged into a single header
`<__type_traits/integer_traits.h>`.
- `__libcpp_signed_integer`, `__libcpp_unsigned_integer` and
`__libcpp_integer` are moved into the same header.
- The above mentioned concepts are renamed to `__signed_integer`,
`__unsigned_integer` and `__signed_or_unsigned_integer` respectively.
2025-06-11 14:31:13 +02:00

38 lines
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//===----------------------------------------------------------------------===//
//
// 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_HAS_SINGLE_BIT_H
#define _LIBCPP___BIT_HAS_SINGLE_BIT_H
#include <__config>
#include <__type_traits/integer_traits.h>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_PUSH_MACROS
#include <__undef_macros>
#if _LIBCPP_STD_VER >= 20
_LIBCPP_BEGIN_NAMESPACE_STD
template <__unsigned_integer _Tp>
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr bool has_single_bit(_Tp __t) noexcept {
return __t != 0 && (((__t & (__t - 1)) == 0));
}
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP_STD_VER >= 20
_LIBCPP_POP_MACROS
#endif // _LIBCPP___BIT_HAS_SINGLE_BIT_H