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_POPCOUNT_H |
10 | #define _LIBCPP___BIT_POPCOUNT_H |
11 | |
12 | #include <__config> |
13 | #include <__type_traits/integer_traits.h> |
14 | |
15 | #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
16 | # pragma GCC system_header |
17 | #endif |
18 | |
19 | _LIBCPP_PUSH_MACROS |
20 | #include <__undef_macros> |
21 | |
22 | _LIBCPP_BEGIN_NAMESPACE_STD |
23 | |
24 | template <class _Tp> |
25 | [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR int __popcount(_Tp __t) _NOEXCEPT { |
26 | static_assert(__is_unsigned_integer_v<_Tp>, "__popcount only works with unsigned types"); |
27 | return __builtin_popcountg(__t); |
28 | } |
29 | |
30 | #if _LIBCPP_STD_VER >= 20 |
31 | |
32 | template <__unsigned_integer _Tp> |
33 | [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr int popcount(_Tp __t) noexcept { |
34 | return std::__popcount(__t); |
35 | } |
36 | |
37 | #endif |
38 | |
39 | _LIBCPP_END_NAMESPACE_STD |
40 | |
41 | _LIBCPP_POP_MACROS |
42 | |
43 | #endif // _LIBCPP___BIT_POPCOUNT_H |
44 |