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 countl_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::countl_zero(T())), int);
33 ASSERT_NOEXCEPT(std::countl_zero(T()));
34 T max = std::numeric_limits<T>::max();
35 int dig = std::numeric_limits<T>::digits;
36
37 assert(std::countl_zero(T(0)) == dig);
38 assert(std::countl_zero(T(1)) == dig - 1);
39 assert(std::countl_zero(T(2)) == dig - 2);
40 assert(std::countl_zero(T(3)) == dig - 2);
41 assert(std::countl_zero(T(4)) == dig - 3);
42 assert(std::countl_zero(T(5)) == dig - 3);
43 assert(std::countl_zero(T(6)) == dig - 3);
44 assert(std::countl_zero(T(7)) == dig - 3);
45 assert(std::countl_zero(T(8)) == dig - 4);
46 assert(std::countl_zero(T(9)) == dig - 4);
47 assert(std::countl_zero(T(127)) == dig - 7);
48 assert(std::countl_zero(T(128)) == dig - 8);
49 assert(std::countl_zero(max) == 0);
50
51 #ifndef TEST_HAS_NO_INT128
52 if constexpr (std::is_same_v<T, __uint128_t>) {
53 T val = T(128) << 32;
54 assert(std::countl_zero(val-1) == 89);
55 assert(std::countl_zero(val) == 88);
56 assert(std::countl_zero(val+1) == 88);
57 val <<= 60;
58 assert(std::countl_zero(val-1) == 29);
59 assert(std::countl_zero(val) == 28);
60 assert(std::countl_zero(val+1) == 28);
61 }
62 #endif
63
64 return true;
65 }
66
main(int,char **)67 int main(int, char**)
68 {
69 {
70 auto lambda = [](auto x) -> decltype(std::countl_zero(x)) {};
71 using L = decltype(lambda);
72
73 static_assert(!std::is_invocable_v<L, signed char>);
74 static_assert(!std::is_invocable_v<L, short>);
75 static_assert(!std::is_invocable_v<L, int>);
76 static_assert(!std::is_invocable_v<L, long>);
77 static_assert(!std::is_invocable_v<L, long long>);
78 #ifndef TEST_HAS_NO_INT128
79 static_assert(!std::is_invocable_v<L, __int128_t>);
80 #endif
81
82 static_assert(!std::is_invocable_v<L, int8_t>);
83 static_assert(!std::is_invocable_v<L, int16_t>);
84 static_assert(!std::is_invocable_v<L, int32_t>);
85 static_assert(!std::is_invocable_v<L, int64_t>);
86 static_assert(!std::is_invocable_v<L, intmax_t>);
87 static_assert(!std::is_invocable_v<L, intptr_t>);
88 static_assert(!std::is_invocable_v<L, ptrdiff_t>);
89
90 static_assert(!std::is_invocable_v<L, bool>);
91 static_assert(!std::is_invocable_v<L, char>);
92 static_assert(!std::is_invocable_v<L, wchar_t>);
93 #ifndef TEST_HAS_NO_CHAR8_T
94 static_assert(!std::is_invocable_v<L, char8_t>);
95 #endif
96 static_assert(!std::is_invocable_v<L, char16_t>);
97 static_assert(!std::is_invocable_v<L, char32_t>);
98
99 static_assert(!std::is_invocable_v<L, A>);
100 static_assert(!std::is_invocable_v<L, A*>);
101 static_assert(!std::is_invocable_v<L, E1>);
102 static_assert(!std::is_invocable_v<L, E2>);
103 }
104
105 static_assert(test<unsigned char>());
106 static_assert(test<unsigned short>());
107 static_assert(test<unsigned int>());
108 static_assert(test<unsigned long>());
109 static_assert(test<unsigned long long>());
110 #ifndef TEST_HAS_NO_INT128
111 static_assert(test<__uint128_t>());
112 #endif
113 static_assert(test<uint8_t>());
114 static_assert(test<uint16_t>());
115 static_assert(test<uint32_t>());
116 static_assert(test<uint64_t>());
117 static_assert(test<uintmax_t>());
118 static_assert(test<uintptr_t>());
119 static_assert(test<size_t>());
120
121 test<unsigned char>();
122 test<unsigned short>();
123 test<unsigned int>();
124 test<unsigned long>();
125 test<unsigned long long>();
126 #ifndef TEST_HAS_NO_INT128
127 test<__uint128_t>();
128 #endif
129 test<uint8_t>();
130 test<uint16_t>();
131 test<uint32_t>();
132 test<uint64_t>();
133 test<uintmax_t>();
134 test<uintptr_t>();
135 test<size_t>();
136
137 return 0;
138 }
139