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_COUNTL_H
10#define _LIBCPP___BIT_COUNTL_H
11
12#include <__config>
13#include <__type_traits/integer_traits.h>
14#include <limits>
15
16#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
17# pragma GCC system_header
18#endif
19
20_LIBCPP_PUSH_MACROS
21#include <__undef_macros>
22
23_LIBCPP_BEGIN_NAMESPACE_STD
24
25template <class _Tp>
26_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 int __countl_zero(_Tp __t) _NOEXCEPT {
27 return __builtin_clzg(__t, numeric_limits<_Tp>::digits);
28}
29
30#if _LIBCPP_STD_VER >= 20
31
32template <__unsigned_integer _Tp>
33[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr int countl_zero(_Tp __t) noexcept {
34 return std::__countl_zero(__t);
35}
36
37template <__unsigned_integer _Tp>
38[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr int countl_one(_Tp __t) noexcept {
39 return std::countl_zero(static_cast<_Tp>(~__t));
40}
41
42#endif // _LIBCPP_STD_VER >= 20
43
44_LIBCPP_END_NAMESPACE_STD
45
46_LIBCPP_POP_MACROS
47
48#endif // _LIBCPP___BIT_COUNTL_H
49