1 // Copyright (C) 2018-2021 Free Software Foundation, Inc. 2 // 3 // This file is part of the GNU ISO C++ Library. This library is free 4 // software; you can redistribute it and/or modify it under the 5 // terms of the GNU General Public License as published by the 6 // Free Software Foundation; either version 3, or (at your option) 7 // any later version. 8 9 // This library is distributed in the hope that it will be useful, 10 // but WITHOUT ANY WARRANTY; without even the implied warranty of 11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 // GNU General Public License for more details. 13 14 // You should have received a copy of the GNU General Public License along 15 // with this library; see the file COPYING3. If not see 16 // <http://www.gnu.org/licenses/>. 17 18 // { dg-options "-std=gnu++2a" } 19 // { dg-do compile { target c++2a } } 20 21 #include <bit> 22 #include <limits> 23 24 template<typename UInt> 25 constexpr auto test(UInt x)26test(UInt x) 27 -> decltype(std::popcount(x)) 28 { 29 static_assert( noexcept(std::popcount(x)) ); 30 31 constexpr unsigned digits = std::numeric_limits<UInt>::digits; 32 33 static_assert( std::popcount((UInt)0) == 0 ); 34 static_assert( std::popcount((UInt)-1) == digits ); 35 static_assert( std::popcount((UInt)-2) == digits - 1 ); 36 static_assert( std::popcount((UInt)127) == 7 ); 37 38 static_assert( std::popcount((UInt)1) == 1 ); 39 static_assert( std::popcount((UInt)2) == 1 ); 40 static_assert( std::popcount((UInt)0x70) == 3 ); 41 42 if constexpr (std::numeric_limits<UInt>::digits > 8) 43 { 44 static_assert( std::popcount((UInt)(0x101)) == 2 ); 45 static_assert( std::popcount((UInt)(0xfff)) == 12 ); 46 } 47 48 if constexpr (std::numeric_limits<UInt>::digits > 64) 49 { 50 static_assert( std::popcount((UInt)0xffffffffffffffff) == 64 ); 51 static_assert( std::popcount(0x5555555555555555 | ((UInt)1 << 64)) == 33 ); 52 static_assert( std::popcount(0x5555555555555555 | ((UInt)3 << 64)) == 34 ); 53 } 54 55 return true; 56 } 57 58 static_assert( test( (unsigned char)0 ) ); 59 static_assert( test( (unsigned short)0 ) ); 60 static_assert( test( (unsigned int)0 ) ); 61 static_assert( test( (unsigned long)0 ) ); 62 static_assert( test( (unsigned long long)0 ) ); 63 64 // std::popcount(T) shall not participate in overload resolution 65 // unless T is an unsigned integer type. did_not_matchX66struct X { constexpr bool did_not_match() { return true; } }; test(...)67constexpr X test(...) { return X{}; } 68 static_assert( test( (bool)0 ).did_not_match() ); 69 static_assert( test( (char)0 ).did_not_match() ); 70 static_assert( test( (int)0 ).did_not_match() ); 71 static_assert( test( (char16_t)0 ).did_not_match() ); 72 static_assert( test( (float)0 ).did_not_match() ); 73 static_assert( test( (void*)0 ).did_not_match() ); 74 static_assert( test( X{} ).did_not_match() ); 75 enum E : unsigned { e }; 76 static_assert( test( e ).did_not_match() ); 77 78 #if !defined(__STRICT_ANSI__) && defined _GLIBCXX_USE_INT128 79 static_assert( test( (unsigned __int128)0 ) ); 80 static_assert( test( (__int128)0 ).did_not_match() ); 81 #endif 82 #if defined(__GLIBCXX_TYPE_INT_N_0) 83 static_assert( test( (unsigned __GLIBCXX_TYPE_INT_N_0)0 ) ); 84 static_assert( test( (__GLIBCXX_TYPE_INT_N_0)0 ).did_not_match() ); 85 #endif 86 #if defined(__GLIBCXX_TYPE_INT_N_1) 87 static_assert( test( (unsigned __GLIBCXX_TYPE_INT_N_1)0 ) ); 88 static_assert( test( (__GLIBCXX_TYPE_INT_N_1)0 ).did_not_match() ); 89 #endif 90 #if defined(__GLIBCXX_TYPE_INT_N_2) 91 static_assert( test( (unsigned __GLIBCXX_TYPE_INT_N_2)0 ) ); 92 static_assert( test( (__GLIBCXX_TYPE_INT_N_2)0 ).did_not_match() ); 93 #endif 94 95 #include <cstddef> 96 static_assert( test( (std::byte)0 ).did_not_match() ); 97