| //===----------------------------------------------------------------------===// |
| // |
| // 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_POPCOUNT_H |
| #define _LIBCPP___BIT_POPCOUNT_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> |
| |
| _LIBCPP_BEGIN_NAMESPACE_STD |
| |
| template <class _Tp> |
| [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR int __popcount(_Tp __t) _NOEXCEPT { |
| static_assert(__is_unsigned_integer_v<_Tp>, "__popcount only works with unsigned types"); |
| return __builtin_popcountg(__t); |
| } |
| |
| #if _LIBCPP_STD_VER >= 20 |
| |
| template <__unsigned_integer _Tp> |
| [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr int popcount(_Tp __t) noexcept { |
| return std::__popcount(__t); |
| } |
| |
| #endif |
| |
| _LIBCPP_END_NAMESPACE_STD |
| |
| _LIBCPP_POP_MACROS |
| |
| #endif // _LIBCPP___BIT_POPCOUNT_H |
