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
26struct A {};
27enum E1 : unsigned char { rEd };
28enum class E2 : unsigned char { red };
29
30template <class T>
31constexpr 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
70int 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

source code of libcxx/test/std/numerics/bit/bit.pow.two/bit_floor.pass.cpp