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-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 // UNSUPPORTED: c++03, c++11, c++14, c++17 10 11 // template <class T> 12 // constexpr T bit_floor(T x) noexcept; 13 14 // Constraints: T is an unsigned integer type 15 // Returns: If x == 0, 0; otherwise the maximal value y such that bit_floor(y) is true and y <= x. 16 17 #include <bit> 18 #include <cassert> 19 #include <cstddef> 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::bit_floor(T())), T); 34 LIBCPP_ASSERT_NOEXCEPT(std::bit_floor(T())); 35 T max = std::numeric_limits<T>::max(); 36 37 assert(std::bit_floor(T(0)) == T(0)); 38 assert(std::bit_floor(T(1)) == T(1)); 39 assert(std::bit_floor(T(2)) == T(2)); 40 assert(std::bit_floor(T(3)) == T(2)); 41 assert(std::bit_floor(T(4)) == T(4)); 42 assert(std::bit_floor(T(5)) == T(4)); 43 assert(std::bit_floor(T(6)) == T(4)); 44 assert(std::bit_floor(T(7)) == T(4)); 45 assert(std::bit_floor(T(8)) == T(8)); 46 assert(std::bit_floor(T(9)) == T(8)); 47 assert(std::bit_floor(T(125)) == T(64)); 48 assert(std::bit_floor(T(126)) == T(64)); 49 assert(std::bit_floor(T(127)) == T(64)); 50 assert(std::bit_floor(T(128)) == T(128)); 51 assert(std::bit_floor(T(129)) == T(128)); 52 assert(std::bit_floor(max) == T(max - (max >> 1))); 53 54 #ifndef TEST_HAS_NO_INT128 55 if constexpr (std::is_same_v<T, __uint128_t>) { 56 T val = T(128) << 32; 57 assert(std::bit_floor(val-1) == val/2); 58 assert(std::bit_floor(val) == val); 59 assert(std::bit_floor(val+1) == val); 60 val <<= 60; 61 assert(std::bit_floor(val-1) == val/2); 62 assert(std::bit_floor(val) == val); 63 assert(std::bit_floor(val+1) == val); 64 } 65 #endif 66 67 return true; 68 } 69 70 int main(int, char**) 71 { 72 { 73 auto lambda = [](auto x) -> decltype(std::bit_floor(x)) {}; 74 using L = decltype(lambda); 75 76 static_assert(!std::is_invocable_v<L, signed char>); 77 static_assert(!std::is_invocable_v<L, short>); 78 static_assert(!std::is_invocable_v<L, int>); 79 static_assert(!std::is_invocable_v<L, long>); 80 static_assert(!std::is_invocable_v<L, long long>); 81 #ifndef TEST_HAS_NO_INT128 82 static_assert(!std::is_invocable_v<L, __int128_t>); 83 #endif 84 85 static_assert(!std::is_invocable_v<L, std::int8_t>); 86 static_assert(!std::is_invocable_v<L, std::int16_t>); 87 static_assert(!std::is_invocable_v<L, std::int32_t>); 88 static_assert(!std::is_invocable_v<L, std::int64_t>); 89 static_assert(!std::is_invocable_v<L, std::intmax_t>); 90 static_assert(!std::is_invocable_v<L, std::intptr_t>); 91 static_assert(!std::is_invocable_v<L, std::ptrdiff_t>); 92 93 static_assert(!std::is_invocable_v<L, bool>); 94 static_assert(!std::is_invocable_v<L, char>); 95 static_assert(!std::is_invocable_v<L, wchar_t>); 96 #ifndef TEST_HAS_NO_CHAR8_T 97 static_assert(!std::is_invocable_v<L, char8_t>); 98 #endif 99 static_assert(!std::is_invocable_v<L, char16_t>); 100 static_assert(!std::is_invocable_v<L, char32_t>); 101 102 static_assert(!std::is_invocable_v<L, A>); 103 static_assert(!std::is_invocable_v<L, A*>); 104 static_assert(!std::is_invocable_v<L, E1>); 105 static_assert(!std::is_invocable_v<L, E2>); 106 } 107 108 static_assert(test<unsigned char>()); 109 static_assert(test<unsigned short>()); 110 static_assert(test<unsigned int>()); 111 static_assert(test<unsigned long>()); 112 static_assert(test<unsigned long long>()); 113 #ifndef TEST_HAS_NO_INT128 114 static_assert(test<__uint128_t>()); 115 #endif 116 117 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_INT128 131 test<__uint128_t>(); 132 #endif 133 134 test<std::uint8_t>(); 135 test<std::uint16_t>(); 136 test<std::uint32_t>(); 137 test<std::uint64_t>(); 138 test<std::uintmax_t>(); 139 test<std::uintptr_t>(); 140 test<std::size_t>(); 141 142 return 0; 143 } 144