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 countr_one(T x) noexcept;
13
14 // Constraints: T is an unsigned integer type
15 // Returns: The number of consecutive 1 bits, starting from the least significant bit.
16 // [ Note: Returns N if x == std::numeric_limits<T>::max(). ]
17
18 #include <bit>
19 #include <cstdint>
20 #include <type_traits>
21 #include <cassert>
22
23 #include "test_macros.h"
24
25 struct A {};
26 enum E1 : unsigned char { rEd };
27 enum class E2 : unsigned char { red };
28
29 template <class T>
test()30 constexpr bool test()
31 {
32 ASSERT_SAME_TYPE(decltype(std::countr_one(T())), int);
33 ASSERT_NOEXCEPT(std::countr_one(T()));
34 T max = std::numeric_limits<T>::max();
35
36 assert(std::countr_one(T(0)) == 0);
37 assert(std::countr_one(T(1)) == 1);
38 assert(std::countr_one(T(2)) == 0);
39 assert(std::countr_one(T(3)) == 2);
40 assert(std::countr_one(T(4)) == 0);
41 assert(std::countr_one(T(5)) == 1);
42 assert(std::countr_one(T(6)) == 0);
43 assert(std::countr_one(T(7)) == 3);
44 assert(std::countr_one(T(8)) == 0);
45 assert(std::countr_one(T(9)) == 1);
46 assert(std::countr_one(T(126)) == 0);
47 assert(std::countr_one(T(127)) == 7);
48 assert(std::countr_one(T(128)) == 0);
49 assert(std::countr_one(T(max - 1)) == 0);
50 assert(std::countr_one(max) == std::numeric_limits<T>::digits);
51
52 #ifndef TEST_HAS_NO_INT128
53 if constexpr (std::is_same_v<T, __uint128_t>) {
54 T val = 128;
55 assert(std::countr_one(val-1) == 7);
56 assert(std::countr_one(val) == 0);
57 assert(std::countr_one(val+1) == 1);
58 val <<= 32;
59 assert(std::countr_one(val-1) == 39);
60 assert(std::countr_one(val) == 0);
61 assert(std::countr_one(val+1) == 1);
62 val <<= 60;
63 assert(std::countr_one(val-1) == 99);
64 assert(std::countr_one(val) == 0);
65 assert(std::countr_one(val+1) == 1);
66 }
67 #endif
68
69 return true;
70 }
71
main(int,char **)72 int main(int, char**)
73 {
74 {
75 auto lambda = [](auto x) -> decltype(std::countr_one(x)) {};
76 using L = decltype(lambda);
77
78 static_assert(!std::is_invocable_v<L, signed char>);
79 static_assert(!std::is_invocable_v<L, short>);
80 static_assert(!std::is_invocable_v<L, int>);
81 static_assert(!std::is_invocable_v<L, long>);
82 static_assert(!std::is_invocable_v<L, long long>);
83 #ifndef TEST_HAS_NO_INT128
84 static_assert(!std::is_invocable_v<L, __int128_t>);
85 #endif
86
87 static_assert(!std::is_invocable_v<L, int8_t>);
88 static_assert(!std::is_invocable_v<L, int16_t>);
89 static_assert(!std::is_invocable_v<L, int32_t>);
90 static_assert(!std::is_invocable_v<L, int64_t>);
91 static_assert(!std::is_invocable_v<L, intmax_t>);
92 static_assert(!std::is_invocable_v<L, intptr_t>);
93 static_assert(!std::is_invocable_v<L, ptrdiff_t>);
94
95 static_assert(!std::is_invocable_v<L, bool>);
96 static_assert(!std::is_invocable_v<L, char>);
97 static_assert(!std::is_invocable_v<L, wchar_t>);
98 #ifndef TEST_HAS_NO_CHAR8_T
99 static_assert(!std::is_invocable_v<L, char8_t>);
100 #endif
101 static_assert(!std::is_invocable_v<L, char16_t>);
102 static_assert(!std::is_invocable_v<L, char32_t>);
103
104 static_assert(!std::is_invocable_v<L, A>);
105 static_assert(!std::is_invocable_v<L, A*>);
106 static_assert(!std::is_invocable_v<L, E1>);
107 static_assert(!std::is_invocable_v<L, E2>);
108 }
109
110 static_assert(test<unsigned char>());
111 static_assert(test<unsigned short>());
112 static_assert(test<unsigned int>());
113 static_assert(test<unsigned long>());
114 static_assert(test<unsigned long long>());
115 #ifndef TEST_HAS_NO_INT128
116 static_assert(test<__uint128_t>());
117 #endif
118 static_assert(test<uint8_t>());
119 static_assert(test<uint16_t>());
120 static_assert(test<uint32_t>());
121 static_assert(test<uint64_t>());
122 static_assert(test<uintmax_t>());
123 static_assert(test<uintptr_t>());
124 static_assert(test<size_t>());
125
126 test<unsigned char>();
127 test<unsigned short>();
128 test<unsigned int>();
129 test<unsigned long>();
130 test<unsigned long long>();
131 #ifndef TEST_HAS_NO_INT128
132 test<__uint128_t>();
133 #endif
134 test<uint8_t>();
135 test<uint16_t>();
136 test<uint32_t>();
137 test<uint64_t>();
138 test<uintmax_t>();
139 test<uintptr_t>();
140 test<size_t>();
141
142 return 0;
143 }
144