141 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 countl_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::countl_zero(T())), int);35 ASSERT_NOEXCEPT(std::countl_zero(T()));36 T max = std::numeric_limits<T>::max();37 int dig = std::numeric_limits<T>::digits;38 39 assert(std::countl_zero(T(0)) == dig);40 assert(std::countl_zero(T(1)) == dig - 1);41 assert(std::countl_zero(T(2)) == dig - 2);42 assert(std::countl_zero(T(3)) == dig - 2);43 assert(std::countl_zero(T(4)) == dig - 3);44 assert(std::countl_zero(T(5)) == dig - 3);45 assert(std::countl_zero(T(6)) == dig - 3);46 assert(std::countl_zero(T(7)) == dig - 3);47 assert(std::countl_zero(T(8)) == dig - 4);48 assert(std::countl_zero(T(9)) == dig - 4);49 assert(std::countl_zero(T(127)) == dig - 7);50 assert(std::countl_zero(T(128)) == dig - 8);51 assert(std::countl_zero(max) == 0);52 53#ifndef TEST_HAS_NO_INT12854 if constexpr (std::is_same_v<T, __uint128_t>) {55 T val = T(128) << 32;56 assert(std::countl_zero(val-1) == 89);57 assert(std::countl_zero(val) == 88);58 assert(std::countl_zero(val+1) == 88);59 val <<= 60;60 assert(std::countl_zero(val-1) == 29);61 assert(std::countl_zero(val) == 28);62 assert(std::countl_zero(val+1) == 28);63 }64#endif65 66 return true;67}68 69int main(int, char**)70{71 {72 auto lambda = [](auto x) -> decltype(std::countl_zero(x)) {};73 using L = decltype(lambda);74 75 static_assert(!std::is_invocable_v<L, signed char>);76 static_assert(!std::is_invocable_v<L, short>);77 static_assert(!std::is_invocable_v<L, int>);78 static_assert(!std::is_invocable_v<L, long>);79 static_assert(!std::is_invocable_v<L, long long>);80#ifndef TEST_HAS_NO_INT12881 static_assert(!std::is_invocable_v<L, __int128_t>);82#endif83 84 static_assert(!std::is_invocable_v<L, std::int8_t>);85 static_assert(!std::is_invocable_v<L, std::int16_t>);86 static_assert(!std::is_invocable_v<L, std::int32_t>);87 static_assert(!std::is_invocable_v<L, std::int64_t>);88 static_assert(!std::is_invocable_v<L, std::intmax_t>);89 static_assert(!std::is_invocable_v<L, std::intptr_t>);90 static_assert(!std::is_invocable_v<L, std::ptrdiff_t>);91 92 static_assert(!std::is_invocable_v<L, bool>);93 static_assert(!std::is_invocable_v<L, char>);94 static_assert(!std::is_invocable_v<L, wchar_t>);95#ifndef TEST_HAS_NO_CHAR8_T96 static_assert(!std::is_invocable_v<L, char8_t>);97#endif98 static_assert(!std::is_invocable_v<L, char16_t>);99 static_assert(!std::is_invocable_v<L, char32_t>);100 101 static_assert(!std::is_invocable_v<L, A>);102 static_assert(!std::is_invocable_v<L, A*>);103 static_assert(!std::is_invocable_v<L, E1>);104 static_assert(!std::is_invocable_v<L, E2>);105 }106 107 static_assert(test<unsigned char>());108 static_assert(test<unsigned short>());109 static_assert(test<unsigned int>());110 static_assert(test<unsigned long>());111 static_assert(test<unsigned long long>());112#ifndef TEST_HAS_NO_INT128113 static_assert(test<__uint128_t>());114#endif115 static_assert(test<std::uint8_t>());116 static_assert(test<std::uint16_t>());117 static_assert(test<std::uint32_t>());118 static_assert(test<std::uint64_t>());119 static_assert(test<std::uintmax_t>());120 static_assert(test<std::uintptr_t>());121 static_assert(test<std::size_t>());122 123 test<unsigned char>();124 test<unsigned short>();125 test<unsigned int>();126 test<unsigned long>();127 test<unsigned long long>();128#ifndef TEST_HAS_NO_INT128129 test<__uint128_t>();130#endif131 test<std::uint8_t>();132 test<std::uint16_t>();133 test<std::uint32_t>();134 test<std::uint64_t>();135 test<std::uintmax_t>();136 test<std::uintptr_t>();137 test<std::size_t>();138 139 return 0;140}141