1//===----------------------------------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#ifndef _LIBCPP___BIT_BIT_WIDTH_H
10#define _LIBCPP___BIT_BIT_WIDTH_H
11
12#include <__bit/bit_log2.h>
13#include <__concepts/arithmetic.h>
14#include <__config>
15
16#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
17# pragma GCC system_header
18#endif
19
20#if _LIBCPP_STD_VER >= 20
21
22_LIBCPP_BEGIN_NAMESPACE_STD
23
24template <__libcpp_unsigned_integer _Tp>
25[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr int bit_width(_Tp __t) noexcept {
26 return __t == 0 ? 0 : std::__bit_log2(__t) + 1;
27}
28
29_LIBCPP_END_NAMESPACE_STD
30
31#endif // _LIBCPP_STD_VER >= 20
32
33#endif // _LIBCPP___BIT_BIT_WIDTH_H
34