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 <__bit/rotate.h> 13 #include <__concepts/arithmetic.h> 14 #include <__config> 15 #include <limits> 16 17 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 18 # pragma GCC system_header 19 #endif 20 21 _LIBCPP_PUSH_MACROS 22 #include <__undef_macros> 23 24 _LIBCPP_BEGIN_NAMESPACE_STD 25 26 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR int __libcpp_popcount(unsigned __x) _NOEXCEPT { 27 return __builtin_popcount(__x); 28 } 29 30 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR int __libcpp_popcount(unsigned long __x) _NOEXCEPT { 31 return __builtin_popcountl(__x); 32 } 33 34 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR int __libcpp_popcount(unsigned long long __x) _NOEXCEPT { 35 return __builtin_popcountll(__x); 36 } 37 38 #if _LIBCPP_STD_VER >= 20 39 40 template <__libcpp_unsigned_integer _Tp> 41 _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr int popcount(_Tp __t) noexcept { 42 if (sizeof(_Tp) <= sizeof(unsigned int)) 43 return std::__libcpp_popcount(static_cast<unsigned int>(__t)); 44 else if (sizeof(_Tp) <= sizeof(unsigned long)) 45 return std::__libcpp_popcount(static_cast<unsigned long>(__t)); 46 else if (sizeof(_Tp) <= sizeof(unsigned long long)) 47 return std::__libcpp_popcount(static_cast<unsigned long long>(__t)); 48 else { 49 int __ret = 0; 50 while (__t != 0) { 51 __ret += std::__libcpp_popcount(static_cast<unsigned long long>(__t)); 52 __t >>= numeric_limits<unsigned long long>::digits; 53 } 54 return __ret; 55 } 56 } 57 58 #endif // _LIBCPP_STD_VER >= 20 59 60 _LIBCPP_END_NAMESPACE_STD 61 62 _LIBCPP_POP_MACROS 63 64 #endif // _LIBCPP___BIT_POPCOUNT_H 65