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_INLINE_VISIBILITY _LIBCPP_CONSTEXPR 27 int __libcpp_popcount(unsigned __x) _NOEXCEPT { return __builtin_popcount(__x); } 28 29 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR 30 int __libcpp_popcount(unsigned long __x) _NOEXCEPT { return __builtin_popcountl(__x); } 31 32 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR 33 int __libcpp_popcount(unsigned long long __x) _NOEXCEPT { return __builtin_popcountll(__x); } 34 35 #if _LIBCPP_STD_VER >= 20 36 37 template <__libcpp_unsigned_integer _Tp> 38 _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr int popcount(_Tp __t) noexcept { 39 if (sizeof(_Tp) <= sizeof(unsigned int)) 40 return std::__libcpp_popcount(static_cast<unsigned int>(__t)); 41 else if (sizeof(_Tp) <= sizeof(unsigned long)) 42 return std::__libcpp_popcount(static_cast<unsigned long>(__t)); 43 else if (sizeof(_Tp) <= sizeof(unsigned long long)) 44 return std::__libcpp_popcount(static_cast<unsigned long long>(__t)); 45 else { 46 int __ret = 0; 47 while (__t != 0) { 48 __ret += std::__libcpp_popcount(static_cast<unsigned long long>(__t)); 49 __t >>= numeric_limits<unsigned long long>::digits; 50 } 51 return __ret; 52 } 53 } 54 55 #endif // _LIBCPP_STD_VER >= 20 56 57 _LIBCPP_END_NAMESPACE_STD 58 59 _LIBCPP_POP_MACROS 60 61 #endif // _LIBCPP___BIT_POPCOUNT_H 62