1bdd1243dSDimitry Andric //===----------------------------------------------------------------------===// 2bdd1243dSDimitry Andric // 3bdd1243dSDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4bdd1243dSDimitry Andric // See https://llvm.org/LICENSE.txt for license information. 5bdd1243dSDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6bdd1243dSDimitry Andric // 7bdd1243dSDimitry Andric //===----------------------------------------------------------------------===// 8bdd1243dSDimitry Andric 9*0fca6ea1SDimitry Andric // TODO: __builtin_popcountg is available since Clang 19 and GCC 14. When support for older versions is dropped, we can 10*0fca6ea1SDimitry Andric // refactor this code to exclusively use __builtin_popcountg. 11*0fca6ea1SDimitry Andric 12bdd1243dSDimitry Andric #ifndef _LIBCPP___BIT_POPCOUNT_H 13bdd1243dSDimitry Andric #define _LIBCPP___BIT_POPCOUNT_H 14bdd1243dSDimitry Andric 15bdd1243dSDimitry Andric #include <__bit/rotate.h> 16bdd1243dSDimitry Andric #include <__concepts/arithmetic.h> 17bdd1243dSDimitry Andric #include <__config> 18bdd1243dSDimitry Andric #include <limits> 19bdd1243dSDimitry Andric 20bdd1243dSDimitry Andric #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 21bdd1243dSDimitry Andric # pragma GCC system_header 22bdd1243dSDimitry Andric #endif 23bdd1243dSDimitry Andric 24bdd1243dSDimitry Andric _LIBCPP_PUSH_MACROS 25bdd1243dSDimitry Andric #include <__undef_macros> 26bdd1243dSDimitry Andric 27bdd1243dSDimitry Andric _LIBCPP_BEGIN_NAMESPACE_STD 28bdd1243dSDimitry Andric __libcpp_popcount(unsigned __x)29cb14a3feSDimitry Andricinline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR int __libcpp_popcount(unsigned __x) _NOEXCEPT { 30cb14a3feSDimitry Andric return __builtin_popcount(__x); 31cb14a3feSDimitry Andric } 32bdd1243dSDimitry Andric __libcpp_popcount(unsigned long __x)33cb14a3feSDimitry Andricinline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR int __libcpp_popcount(unsigned long __x) _NOEXCEPT { 34cb14a3feSDimitry Andric return __builtin_popcountl(__x); 35cb14a3feSDimitry Andric } 36bdd1243dSDimitry Andric __libcpp_popcount(unsigned long long __x)37cb14a3feSDimitry Andricinline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR int __libcpp_popcount(unsigned long long __x) _NOEXCEPT { 38cb14a3feSDimitry Andric return __builtin_popcountll(__x); 39cb14a3feSDimitry Andric } 40bdd1243dSDimitry Andric 41bdd1243dSDimitry Andric #if _LIBCPP_STD_VER >= 20 42bdd1243dSDimitry Andric 43bdd1243dSDimitry Andric template <__libcpp_unsigned_integer _Tp> popcount(_Tp __t)44*0fca6ea1SDimitry Andric[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr int popcount(_Tp __t) noexcept { 45*0fca6ea1SDimitry Andric # if __has_builtin(__builtin_popcountg) 46*0fca6ea1SDimitry Andric return __builtin_popcountg(__t); 47*0fca6ea1SDimitry Andric # else // __has_builtin(__builtin_popcountg) 48bdd1243dSDimitry Andric if (sizeof(_Tp) <= sizeof(unsigned int)) 49bdd1243dSDimitry Andric return std::__libcpp_popcount(static_cast<unsigned int>(__t)); 50bdd1243dSDimitry Andric else if (sizeof(_Tp) <= sizeof(unsigned long)) 51bdd1243dSDimitry Andric return std::__libcpp_popcount(static_cast<unsigned long>(__t)); 52bdd1243dSDimitry Andric else if (sizeof(_Tp) <= sizeof(unsigned long long)) 53bdd1243dSDimitry Andric return std::__libcpp_popcount(static_cast<unsigned long long>(__t)); 54bdd1243dSDimitry Andric else { 55bdd1243dSDimitry Andric int __ret = 0; 56bdd1243dSDimitry Andric while (__t != 0) { 57bdd1243dSDimitry Andric __ret += std::__libcpp_popcount(static_cast<unsigned long long>(__t)); 58bdd1243dSDimitry Andric __t >>= numeric_limits<unsigned long long>::digits; 59bdd1243dSDimitry Andric } 60bdd1243dSDimitry Andric return __ret; 61bdd1243dSDimitry Andric } 62*0fca6ea1SDimitry Andric # endif // __has_builtin(__builtin_popcountg) 63bdd1243dSDimitry Andric } 64bdd1243dSDimitry Andric 65bdd1243dSDimitry Andric #endif // _LIBCPP_STD_VER >= 20 66bdd1243dSDimitry Andric 67bdd1243dSDimitry Andric _LIBCPP_END_NAMESPACE_STD 68bdd1243dSDimitry Andric 69bdd1243dSDimitry Andric _LIBCPP_POP_MACROS 70bdd1243dSDimitry Andric 71bdd1243dSDimitry Andric #endif // _LIBCPP___BIT_POPCOUNT_H 72