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_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 <type_traits>
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_zero(T())), int);
33 ASSERT_NOEXCEPT(std::countr_zero(T()));
34 T max = std::numeric_limits<T>::max();
35
36 assert(std::countr_zero(T(0)) == std::numeric_limits<T>::digits);
37 assert(std::countr_zero(T(1)) == 0);
38 assert(std::countr_zero(T(2)) == 1);
39 assert(std::countr_zero(T(3)) == 0);
40 assert(std::countr_zero(T(4)) == 2);
41 assert(std::countr_zero(T(5)) == 0);
42 assert(std::countr_zero(T(6)) == 1);
43 assert(std::countr_zero(T(7)) == 0);
44 assert(std::countr_zero(T(8)) == 3);
45 assert(std::countr_zero(T(9)) == 0);
46 assert(std::countr_zero(T(126)) == 1);
47 assert(std::countr_zero(T(127)) == 0);
48 assert(std::countr_zero(T(128)) == 7);
49 assert(std::countr_zero(T(129)) == 0);
50 assert(std::countr_zero(T(130)) == 1);
51 assert(std::countr_zero(max) == 0);
52
53 #ifndef TEST_HAS_NO_INT128
54 if constexpr (std::is_same_v<T, __uint128_t>) {
55 T val = T(128) << 32;
56 assert(std::countr_zero(val-1) == 0);
57 assert(std::countr_zero(val) == 39);
58 assert(std::countr_zero(val+1) == 0);
59 val <<= 60;
60 assert(std::countr_zero(val-1) == 0);
61 assert(std::countr_zero(val) == 99);
62 assert(std::countr_zero(val+1) == 0);
63 }
64 #endif
65
66 return true;
67 }
68
main(int,char **)69 int main(int, char**)
70 {
71 {
72 auto lambda = [](auto x) -> decltype(std::countr_zero(x)) {};
73 using L = decltype(lambda);
74
75 static_assert(!std::is_invocable_v<L, signed char>);
76 static_assert(!std::is_invocable_v<L, short>);
77 static_assert(!std::is_invocable_v<L, int>);
78 static_assert(!std::is_invocable_v<L, long>);
79 static_assert(!std::is_invocable_v<L, long long>);
80 #ifndef TEST_HAS_NO_INT128
81 static_assert(!std::is_invocable_v<L, __int128_t>);
82 #endif
83
84 static_assert(!std::is_invocable_v<L, int8_t>);
85 static_assert(!std::is_invocable_v<L, int16_t>);
86 static_assert(!std::is_invocable_v<L, int32_t>);
87 static_assert(!std::is_invocable_v<L, int64_t>);
88 static_assert(!std::is_invocable_v<L, intmax_t>);
89 static_assert(!std::is_invocable_v<L, intptr_t>);
90 static_assert(!std::is_invocable_v<L, ptrdiff_t>);
91
92 static_assert(!std::is_invocable_v<L, bool>);
93 static_assert(!std::is_invocable_v<L, char>);
94 static_assert(!std::is_invocable_v<L, wchar_t>);
95 #ifndef TEST_HAS_NO_CHAR8_T
96 static_assert(!std::is_invocable_v<L, char8_t>);
97 #endif
98 static_assert(!std::is_invocable_v<L, char16_t>);
99 static_assert(!std::is_invocable_v<L, char32_t>);
100
101 static_assert(!std::is_invocable_v<L, A>);
102 static_assert(!std::is_invocable_v<L, A*>);
103 static_assert(!std::is_invocable_v<L, E1>);
104 static_assert(!std::is_invocable_v<L, E2>);
105 }
106
107 static_assert(test<unsigned char>());
108 static_assert(test<unsigned short>());
109 static_assert(test<unsigned int>());
110 static_assert(test<unsigned long>());
111 static_assert(test<unsigned long long>());
112 #ifndef TEST_HAS_NO_INT128
113 static_assert(test<__uint128_t>());
114 #endif
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 test<uint8_t>();
132 test<uint16_t>();
133 test<uint32_t>();
134 test<uint64_t>();
135 test<uintmax_t>();
136 test<uintptr_t>();
137 test<size_t>();
138
139 return 0;
140 }
141