147 lines · cpp
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-exception6//7//===----------------------------------------------------------------------===//8 9// UNSUPPORTED: c++03, c++11, c++14, c++1710 11// template <class T>12// constexpr int bit_width(T x) noexcept;13 14// Constraints: T is an unsigned integer type15// Returns: If x == 0, 0; otherwise one plus the base-2 logarithm of x, with any fractional part discarded.16 17 18#include <bit>19#include <cassert>20#include <cstddef>21#include <cstdint>22#include <limits>23#include <type_traits>24 25#include "test_macros.h"26 27struct A {};28enum E1 : unsigned char { rEd };29enum class E2 : unsigned char { red };30 31template <class T>32constexpr bool test()33{34 ASSERT_SAME_TYPE(decltype(std::bit_width(T())), int);35 ASSERT_NOEXCEPT(std::bit_width(T()));36 T max = std::numeric_limits<T>::max();37 38 assert(std::bit_width(T(0)) == 0);39 assert(std::bit_width(T(1)) == 1);40 assert(std::bit_width(T(2)) == 2);41 assert(std::bit_width(T(3)) == 2);42 assert(std::bit_width(T(4)) == 3);43 assert(std::bit_width(T(5)) == 3);44 assert(std::bit_width(T(6)) == 3);45 assert(std::bit_width(T(7)) == 3);46 assert(std::bit_width(T(8)) == 4);47 assert(std::bit_width(T(9)) == 4);48 assert(std::bit_width(T(125)) == 7);49 assert(std::bit_width(T(126)) == 7);50 assert(std::bit_width(T(127)) == 7);51 assert(std::bit_width(T(128)) == 8);52 assert(std::bit_width(T(129)) == 8);53 assert(std::bit_width(T(130)) == 8);54 assert(std::bit_width(T(max - 1)) == std::numeric_limits<T>::digits);55 assert(std::bit_width(max) == std::numeric_limits<T>::digits);56 57#ifndef TEST_HAS_NO_INT12858 if constexpr (std::is_same_v<T, __uint128_t>) {59 T val = 128;60 val <<= 32;61 assert(std::bit_width(val-1) == 39);62 assert(std::bit_width(val) == 40);63 assert(std::bit_width(val+1) == 40);64 val <<= 60;65 assert(std::bit_width(val-1) == 99);66 assert(std::bit_width(val) == 100);67 assert(std::bit_width(val+1) == 100);68 }69#endif70 71 return true;72}73 74int main(int, char**)75{76 77 {78 auto lambda = [](auto x) -> decltype(std::bit_width(x)) {};79 using L = decltype(lambda);80 81 static_assert(!std::is_invocable_v<L, signed char>);82 static_assert(!std::is_invocable_v<L, short>);83 static_assert(!std::is_invocable_v<L, int>);84 static_assert(!std::is_invocable_v<L, long>);85 static_assert(!std::is_invocable_v<L, long long>);86#ifndef TEST_HAS_NO_INT12887 static_assert(!std::is_invocable_v<L, __int128_t>);88#endif89 90 static_assert(!std::is_invocable_v<L, std::int8_t>);91 static_assert(!std::is_invocable_v<L, std::int16_t>);92 static_assert(!std::is_invocable_v<L, std::int32_t>);93 static_assert(!std::is_invocable_v<L, std::int64_t>);94 static_assert(!std::is_invocable_v<L, std::intmax_t>);95 static_assert(!std::is_invocable_v<L, std::intptr_t>);96 static_assert(!std::is_invocable_v<L, std::ptrdiff_t>);97 98 static_assert(!std::is_invocable_v<L, bool>);99 static_assert(!std::is_invocable_v<L, char>);100 static_assert(!std::is_invocable_v<L, wchar_t>);101#ifndef TEST_HAS_NO_CHAR8_T102 static_assert(!std::is_invocable_v<L, char8_t>);103#endif104 static_assert(!std::is_invocable_v<L, char16_t>);105 static_assert(!std::is_invocable_v<L, char32_t>);106 107 static_assert(!std::is_invocable_v<L, A>);108 static_assert(!std::is_invocable_v<L, A*>);109 static_assert(!std::is_invocable_v<L, E1>);110 static_assert(!std::is_invocable_v<L, E2>);111 }112 113 static_assert(test<unsigned char>());114 static_assert(test<unsigned short>());115 static_assert(test<unsigned int>());116 static_assert(test<unsigned long>());117 static_assert(test<unsigned long long>());118#ifndef TEST_HAS_NO_INT128119 static_assert(test<__uint128_t>());120#endif121 static_assert(test<std::uint8_t>());122 static_assert(test<std::uint16_t>());123 static_assert(test<std::uint32_t>());124 static_assert(test<std::uint64_t>());125 static_assert(test<std::uintmax_t>());126 static_assert(test<std::uintptr_t>());127 static_assert(test<std::size_t>());128 129 test<unsigned char>();130 test<unsigned short>();131 test<unsigned int>();132 test<unsigned long>();133 test<unsigned long long>();134#ifndef TEST_HAS_NO_INT128135 test<__uint128_t>();136#endif137 test<std::uint8_t>();138 test<std::uint16_t>();139 test<std::uint32_t>();140 test<std::uint64_t>();141 test<std::uintmax_t>();142 test<std::uintptr_t>();143 test<std::size_t>();144 145 return 0;146}147