143 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 countr_zero(T x) noexcept;13 14// Constraints: T is an unsigned integer type15// Returns: The number of consecutive 0 bits, starting from the most significant bit.16// [ Note: Returns N if x == 0. ]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::countr_zero(T())), int);35 ASSERT_NOEXCEPT(std::countr_zero(T()));36 T max = std::numeric_limits<T>::max();37 38 assert(std::countr_zero(T(0)) == std::numeric_limits<T>::digits);39 assert(std::countr_zero(T(1)) == 0);40 assert(std::countr_zero(T(2)) == 1);41 assert(std::countr_zero(T(3)) == 0);42 assert(std::countr_zero(T(4)) == 2);43 assert(std::countr_zero(T(5)) == 0);44 assert(std::countr_zero(T(6)) == 1);45 assert(std::countr_zero(T(7)) == 0);46 assert(std::countr_zero(T(8)) == 3);47 assert(std::countr_zero(T(9)) == 0);48 assert(std::countr_zero(T(126)) == 1);49 assert(std::countr_zero(T(127)) == 0);50 assert(std::countr_zero(T(128)) == 7);51 assert(std::countr_zero(T(129)) == 0);52 assert(std::countr_zero(T(130)) == 1);53 assert(std::countr_zero(max) == 0);54 55#ifndef TEST_HAS_NO_INT12856 if constexpr (std::is_same_v<T, __uint128_t>) {57 T val = T(128) << 32;58 assert(std::countr_zero(val-1) == 0);59 assert(std::countr_zero(val) == 39);60 assert(std::countr_zero(val+1) == 0);61 val <<= 60;62 assert(std::countr_zero(val-1) == 0);63 assert(std::countr_zero(val) == 99);64 assert(std::countr_zero(val+1) == 0);65 }66#endif67 68 return true;69}70 71int main(int, char**)72{73 {74 auto lambda = [](auto x) -> decltype(std::countr_zero(x)) {};75 using L = decltype(lambda);76 77 static_assert(!std::is_invocable_v<L, signed char>);78 static_assert(!std::is_invocable_v<L, short>);79 static_assert(!std::is_invocable_v<L, int>);80 static_assert(!std::is_invocable_v<L, long>);81 static_assert(!std::is_invocable_v<L, long long>);82#ifndef TEST_HAS_NO_INT12883 static_assert(!std::is_invocable_v<L, __int128_t>);84#endif85 86 static_assert(!std::is_invocable_v<L, std::int8_t>);87 static_assert(!std::is_invocable_v<L, std::int16_t>);88 static_assert(!std::is_invocable_v<L, std::int32_t>);89 static_assert(!std::is_invocable_v<L, std::int64_t>);90 static_assert(!std::is_invocable_v<L, std::intmax_t>);91 static_assert(!std::is_invocable_v<L, std::intptr_t>);92 static_assert(!std::is_invocable_v<L, std::ptrdiff_t>);93 94 static_assert(!std::is_invocable_v<L, bool>);95 static_assert(!std::is_invocable_v<L, char>);96 static_assert(!std::is_invocable_v<L, wchar_t>);97#ifndef TEST_HAS_NO_CHAR8_T98 static_assert(!std::is_invocable_v<L, char8_t>);99#endif100 static_assert(!std::is_invocable_v<L, char16_t>);101 static_assert(!std::is_invocable_v<L, char32_t>);102 103 static_assert(!std::is_invocable_v<L, A>);104 static_assert(!std::is_invocable_v<L, A*>);105 static_assert(!std::is_invocable_v<L, E1>);106 static_assert(!std::is_invocable_v<L, E2>);107 }108 109 static_assert(test<unsigned char>());110 static_assert(test<unsigned short>());111 static_assert(test<unsigned int>());112 static_assert(test<unsigned long>());113 static_assert(test<unsigned long long>());114#ifndef TEST_HAS_NO_INT128115 static_assert(test<__uint128_t>());116#endif117 static_assert(test<std::uint8_t>());118 static_assert(test<std::uint16_t>());119 static_assert(test<std::uint32_t>());120 static_assert(test<std::uint64_t>());121 static_assert(test<std::uintmax_t>());122 static_assert(test<std::uintptr_t>());123 static_assert(test<std::size_t>());124 125 test<unsigned char>();126 test<unsigned short>();127 test<unsigned int>();128 test<unsigned long>();129 test<unsigned long long>();130#ifndef TEST_HAS_NO_INT128131 test<__uint128_t>();132#endif133 test<std::uint8_t>();134 test<std::uint16_t>();135 test<std::uint32_t>();136 test<std::uint64_t>();137 test<std::uintmax_t>();138 test<std::uintptr_t>();139 test<std::size_t>();140 141 return 0;142}143