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 int countl_zero(T x) noexcept; 13 14 // Constraints: T is an unsigned integer type 15 // 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 <cstdint> 21 #include <limits> 22 #include <type_traits> 23 24 #include "test_macros.h" 25 26 struct A {}; 27 enum E1 : unsigned char { rEd }; 28 enum class E2 : unsigned char { red }; 29 30 template <class T> 31 constexpr bool test() 32 { 33 ASSERT_SAME_TYPE(decltype(std::countl_zero(T())), int); 34 ASSERT_NOEXCEPT(std::countl_zero(T())); 35 T max = std::numeric_limits<T>::max(); 36 int dig = std::numeric_limits<T>::digits; 37 38 assert(std::countl_zero(T(0)) == dig); 39 assert(std::countl_zero(T(1)) == dig - 1); 40 assert(std::countl_zero(T(2)) == dig - 2); 41 assert(std::countl_zero(T(3)) == dig - 2); 42 assert(std::countl_zero(T(4)) == dig - 3); 43 assert(std::countl_zero(T(5)) == dig - 3); 44 assert(std::countl_zero(T(6)) == dig - 3); 45 assert(std::countl_zero(T(7)) == dig - 3); 46 assert(std::countl_zero(T(8)) == dig - 4); 47 assert(std::countl_zero(T(9)) == dig - 4); 48 assert(std::countl_zero(T(127)) == dig - 7); 49 assert(std::countl_zero(T(128)) == dig - 8); 50 assert(std::countl_zero(max) == 0); 51 52 #ifndef TEST_HAS_NO_INT128 53 if constexpr (std::is_same_v<T, __uint128_t>) { 54 T val = T(128) << 32; 55 assert(std::countl_zero(val-1) == 89); 56 assert(std::countl_zero(val) == 88); 57 assert(std::countl_zero(val+1) == 88); 58 val <<= 60; 59 assert(std::countl_zero(val-1) == 29); 60 assert(std::countl_zero(val) == 28); 61 assert(std::countl_zero(val+1) == 28); 62 } 63 #endif 64 65 return true; 66 } 67 68 int main(int, char**) 69 { 70 { 71 auto lambda = [](auto x) -> decltype(std::countl_zero(x)) {}; 72 using L = decltype(lambda); 73 74 static_assert(!std::is_invocable_v<L, signed char>); 75 static_assert(!std::is_invocable_v<L, short>); 76 static_assert(!std::is_invocable_v<L, int>); 77 static_assert(!std::is_invocable_v<L, long>); 78 static_assert(!std::is_invocable_v<L, long long>); 79 #ifndef TEST_HAS_NO_INT128 80 static_assert(!std::is_invocable_v<L, __int128_t>); 81 #endif 82 83 static_assert(!std::is_invocable_v<L, std::int8_t>); 84 static_assert(!std::is_invocable_v<L, std::int16_t>); 85 static_assert(!std::is_invocable_v<L, std::int32_t>); 86 static_assert(!std::is_invocable_v<L, std::int64_t>); 87 static_assert(!std::is_invocable_v<L, std::intmax_t>); 88 static_assert(!std::is_invocable_v<L, std::intptr_t>); 89 static_assert(!std::is_invocable_v<L, std::ptrdiff_t>); 90 91 static_assert(!std::is_invocable_v<L, bool>); 92 static_assert(!std::is_invocable_v<L, char>); 93 static_assert(!std::is_invocable_v<L, wchar_t>); 94 #ifndef TEST_HAS_NO_CHAR8_T 95 static_assert(!std::is_invocable_v<L, char8_t>); 96 #endif 97 static_assert(!std::is_invocable_v<L, char16_t>); 98 static_assert(!std::is_invocable_v<L, char32_t>); 99 100 static_assert(!std::is_invocable_v<L, A>); 101 static_assert(!std::is_invocable_v<L, A*>); 102 static_assert(!std::is_invocable_v<L, E1>); 103 static_assert(!std::is_invocable_v<L, E2>); 104 } 105 106 static_assert(test<unsigned char>()); 107 static_assert(test<unsigned short>()); 108 static_assert(test<unsigned int>()); 109 static_assert(test<unsigned long>()); 110 static_assert(test<unsigned long long>()); 111 #ifndef TEST_HAS_NO_INT128 112 static_assert(test<__uint128_t>()); 113 #endif 114 static_assert(test<std::uint8_t>()); 115 static_assert(test<std::uint16_t>()); 116 static_assert(test<std::uint32_t>()); 117 static_assert(test<std::uint64_t>()); 118 static_assert(test<std::uintmax_t>()); 119 static_assert(test<std::uintptr_t>()); 120 static_assert(test<std::size_t>()); 121 122 test<unsigned char>(); 123 test<unsigned short>(); 124 test<unsigned int>(); 125 test<unsigned long>(); 126 test<unsigned long long>(); 127 #ifndef TEST_HAS_NO_INT128 128 test<__uint128_t>(); 129 #endif 130 test<std::uint8_t>(); 131 test<std::uint16_t>(); 132 test<std::uint32_t>(); 133 test<std::uint64_t>(); 134 test<std::uintmax_t>(); 135 test<std::uintptr_t>(); 136 test<std::size_t>(); 137 138 return 0; 139 } 140