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 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 <cstdint>
20 #include <type_traits>
21
22 #include "test_macros.h"
23
24 struct A {};
25 enum E1 : unsigned char { rEd };
26 enum class E2 : unsigned char { red };
27
28 template <class T>
test()29 constexpr bool test()
30 {
31 ASSERT_SAME_TYPE(decltype(std::bit_floor(T())), T);
32 LIBCPP_ASSERT_NOEXCEPT(std::bit_floor(T()));
33 T max = std::numeric_limits<T>::max();
34
35 assert(std::bit_floor(T(0)) == T(0));
36 assert(std::bit_floor(T(1)) == T(1));
37 assert(std::bit_floor(T(2)) == T(2));
38 assert(std::bit_floor(T(3)) == T(2));
39 assert(std::bit_floor(T(4)) == T(4));
40 assert(std::bit_floor(T(5)) == T(4));
41 assert(std::bit_floor(T(6)) == T(4));
42 assert(std::bit_floor(T(7)) == T(4));
43 assert(std::bit_floor(T(8)) == T(8));
44 assert(std::bit_floor(T(9)) == T(8));
45 assert(std::bit_floor(T(125)) == T(64));
46 assert(std::bit_floor(T(126)) == T(64));
47 assert(std::bit_floor(T(127)) == T(64));
48 assert(std::bit_floor(T(128)) == T(128));
49 assert(std::bit_floor(T(129)) == T(128));
50 assert(std::bit_floor(max) == T(max - (max >> 1)));
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::bit_floor(val-1) == val/2);
56 assert(std::bit_floor(val) == val);
57 assert(std::bit_floor(val+1) == val);
58 val <<= 60;
59 assert(std::bit_floor(val-1) == val/2);
60 assert(std::bit_floor(val) == val);
61 assert(std::bit_floor(val+1) == val);
62 }
63 #endif
64
65 return true;
66 }
67
main(int,char **)68 int main(int, char**)
69 {
70 {
71 auto lambda = [](auto x) -> decltype(std::bit_floor(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, int8_t>);
84 static_assert(!std::is_invocable_v<L, int16_t>);
85 static_assert(!std::is_invocable_v<L, int32_t>);
86 static_assert(!std::is_invocable_v<L, int64_t>);
87 static_assert(!std::is_invocable_v<L, intmax_t>);
88 static_assert(!std::is_invocable_v<L, intptr_t>);
89 static_assert(!std::is_invocable_v<L, 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
115 static_assert(test<uint8_t>());
116 static_assert(test<uint16_t>());
117 static_assert(test<uint32_t>());
118 static_assert(test<uint64_t>());
119 static_assert(test<uintmax_t>());
120 static_assert(test<uintptr_t>());
121 static_assert(test<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_INT128
129 test<__uint128_t>();
130 #endif
131
132 test<uint8_t>();
133 test<uint16_t>();
134 test<uint32_t>();
135 test<uint64_t>();
136 test<uintmax_t>();
137 test<uintptr_t>();
138 test<size_t>();
139
140 return 0;
141 }
142