1 //===----------------------------------------------------------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is dual licensed under the MIT and the University of Illinois Open 6 // Source Licenses. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // UNSUPPORTED: c++03, c++11, c++14, c++17 10 11 // template <class T> 12 // constexpr T bit_width(T x) noexcept; 13 14 // If x == 0, 0; otherwise one plus the base-2 logarithm of x, with any fractional part discarded. 15 16 // Remarks: This function shall not participate in overload resolution unless 17 // T is an unsigned integer type 18 19 #include <bit> 20 #include <cstdint> 21 #include <cassert> 22 23 #include "test_macros.h" 24 25 class A{}; 26 enum E1 : unsigned char { rEd }; 27 enum class E2 : unsigned char { red }; 28 29 template <typename T> 30 constexpr bool constexpr_test() 31 { 32 return std::bit_width(T(0)) == T(0) 33 && std::bit_width(T(1)) == T(1) 34 && std::bit_width(T(2)) == T(2) 35 && std::bit_width(T(3)) == T(2) 36 && std::bit_width(T(4)) == T(3) 37 && std::bit_width(T(5)) == T(3) 38 && std::bit_width(T(6)) == T(3) 39 && std::bit_width(T(7)) == T(3) 40 && std::bit_width(T(8)) == T(4) 41 && std::bit_width(T(9)) == T(4) 42 ; 43 } 44 45 46 template <typename T> 47 void runtime_test() 48 { 49 ASSERT_SAME_TYPE(T, decltype(std::bit_width(T(0)))); 50 ASSERT_NOEXCEPT( std::bit_width(T(0))); 51 52 assert( std::bit_width(T(0)) == T(0)); 53 assert( std::bit_width(T(1)) == T(1)); 54 assert( std::bit_width(T(2)) == T(2)); 55 assert( std::bit_width(T(3)) == T(2)); 56 assert( std::bit_width(T(4)) == T(3)); 57 assert( std::bit_width(T(5)) == T(3)); 58 assert( std::bit_width(T(6)) == T(3)); 59 assert( std::bit_width(T(7)) == T(3)); 60 assert( std::bit_width(T(8)) == T(4)); 61 assert( std::bit_width(T(9)) == T(4)); 62 63 64 assert( std::bit_width(T(121)) == T(7)); 65 assert( std::bit_width(T(122)) == T(7)); 66 assert( std::bit_width(T(123)) == T(7)); 67 assert( std::bit_width(T(124)) == T(7)); 68 assert( std::bit_width(T(125)) == T(7)); 69 assert( std::bit_width(T(126)) == T(7)); 70 assert( std::bit_width(T(127)) == T(7)); 71 assert( std::bit_width(T(128)) == T(8)); 72 assert( std::bit_width(T(129)) == T(8)); 73 assert( std::bit_width(T(130)) == T(8)); 74 } 75 76 int main(int, char**) 77 { 78 79 { 80 auto lambda = [](auto x) -> decltype(std::bit_width(x)) {}; 81 using L = decltype(lambda); 82 83 static_assert( std::is_invocable_v<L, unsigned char>, ""); 84 static_assert( std::is_invocable_v<L, unsigned int>, ""); 85 static_assert( std::is_invocable_v<L, unsigned long>, ""); 86 static_assert( std::is_invocable_v<L, unsigned long long>, ""); 87 88 static_assert( std::is_invocable_v<L, uint8_t>, ""); 89 static_assert( std::is_invocable_v<L, uint16_t>, ""); 90 static_assert( std::is_invocable_v<L, uint32_t>, ""); 91 static_assert( std::is_invocable_v<L, uint64_t>, ""); 92 static_assert( std::is_invocable_v<L, size_t>, ""); 93 94 static_assert( std::is_invocable_v<L, uintmax_t>, ""); 95 static_assert( std::is_invocable_v<L, uintptr_t>, ""); 96 97 98 static_assert(!std::is_invocable_v<L, int>, ""); 99 static_assert(!std::is_invocable_v<L, signed int>, ""); 100 static_assert(!std::is_invocable_v<L, long>, ""); 101 static_assert(!std::is_invocable_v<L, long long>, ""); 102 103 static_assert(!std::is_invocable_v<L, int8_t>, ""); 104 static_assert(!std::is_invocable_v<L, int16_t>, ""); 105 static_assert(!std::is_invocable_v<L, int32_t>, ""); 106 static_assert(!std::is_invocable_v<L, int64_t>, ""); 107 static_assert(!std::is_invocable_v<L, ptrdiff_t>, ""); 108 109 static_assert(!std::is_invocable_v<L, bool>, ""); 110 static_assert(!std::is_invocable_v<L, signed char>, ""); 111 static_assert(!std::is_invocable_v<L, char16_t>, ""); 112 static_assert(!std::is_invocable_v<L, char32_t>, ""); 113 114 #ifndef _LIBCPP_HAS_NO_INT128 115 static_assert( std::is_invocable_v<L, __uint128_t>, ""); 116 static_assert(!std::is_invocable_v<L, __int128_t>, ""); 117 #endif 118 119 static_assert(!std::is_invocable_v<L, A>, ""); 120 static_assert(!std::is_invocable_v<L, E1>, ""); 121 static_assert(!std::is_invocable_v<L, E2>, ""); 122 } 123 124 static_assert(constexpr_test<unsigned char>(), ""); 125 static_assert(constexpr_test<unsigned short>(), ""); 126 static_assert(constexpr_test<unsigned>(), ""); 127 static_assert(constexpr_test<unsigned long>(), ""); 128 static_assert(constexpr_test<unsigned long long>(), ""); 129 130 static_assert(constexpr_test<uint8_t>(), ""); 131 static_assert(constexpr_test<uint16_t>(), ""); 132 static_assert(constexpr_test<uint32_t>(), ""); 133 static_assert(constexpr_test<uint64_t>(), ""); 134 static_assert(constexpr_test<size_t>(), ""); 135 static_assert(constexpr_test<uintmax_t>(), ""); 136 static_assert(constexpr_test<uintptr_t>(), ""); 137 138 #ifndef _LIBCPP_HAS_NO_INT128 139 static_assert(constexpr_test<__uint128_t>(), ""); 140 #endif 141 142 143 runtime_test<unsigned char>(); 144 runtime_test<unsigned>(); 145 runtime_test<unsigned short>(); 146 runtime_test<unsigned long>(); 147 runtime_test<unsigned long long>(); 148 149 runtime_test<uint8_t>(); 150 runtime_test<uint16_t>(); 151 runtime_test<uint32_t>(); 152 runtime_test<uint64_t>(); 153 runtime_test<size_t>(); 154 runtime_test<uintmax_t>(); 155 runtime_test<uintptr_t>(); 156 157 #ifndef _LIBCPP_HAS_NO_INT128 158 runtime_test<__uint128_t>(); 159 160 { 161 __uint128_t val = 128; 162 val <<= 32; 163 assert( std::bit_width(val-1) == 39); 164 assert( std::bit_width(val) == 40); 165 assert( std::bit_width(val+1) == 40); 166 val <<= 2; 167 assert( std::bit_width(val-1) == 41); 168 assert( std::bit_width(val) == 42); 169 assert( std::bit_width(val+1) == 42); 170 val <<= 3; 171 assert( std::bit_width(val-1) == 44); 172 assert( std::bit_width(val) == 45); 173 assert( std::bit_width(val+1) == 45); 174 } 175 #endif 176 177 return 0; 178 } 179