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 //
10 // UNSUPPORTED: c++98, c++03, c++11
11 // <numeric>
12
13 // template<class _M, class _N>
14 // constexpr common_type_t<_M,_N> gcd(_M __m, _N __n)
15
16 #include <experimental/numeric>
17 #include <cassert>
18 #include <cstdlib> // for rand()
19 #include <iostream>
20
21 constexpr struct {
22 int x;
23 int y;
24 int expect;
25 } Cases[] = {
26 {0, 0, 0},
27 {1, 0, 1},
28 {0, 1, 1},
29 {1, 1, 1},
30 {2, 3, 1},
31 {2, 4, 2},
32 {36, 17, 1},
33 {36, 18, 18}
34 };
35
36
37 template <typename Input1, typename Input2, typename Output>
test0(Input1 in1,Input2 in2,Output out)38 constexpr bool test0(Input1 in1, Input2 in2, Output out)
39 {
40 static_assert((std::is_same<Output, decltype(std::experimental::gcd(in1, in2))>::value), "" );
41 static_assert((std::is_same<Output, decltype(std::experimental::gcd(in2, in1))>::value), "" );
42 return out == std::experimental::gcd(in1, in2) ? true : (std::abort(), false);
43 }
44
45
46 template <typename Input1, typename Input2 = Input1>
do_test(int=0)47 constexpr bool do_test(int = 0)
48 {
49 using S1 = typename std::make_signed<Input1>::type;
50 using S2 = typename std::make_signed<Input2>::type;
51 using U1 = typename std::make_unsigned<Input1>::type;
52 using U2 = typename std::make_unsigned<Input2>::type;
53 bool accumulate = true;
54 for (auto TC : Cases) {
55 { // Test with two signed types
56 using Output = std::common_type_t<S1, S2>;
57 accumulate &= test0<S1, S2, Output>(TC.x, TC.y, TC.expect);
58 accumulate &= test0<S1, S2, Output>(-TC.x, TC.y, TC.expect);
59 accumulate &= test0<S1, S2, Output>(TC.x, -TC.y, TC.expect);
60 accumulate &= test0<S1, S2, Output>(-TC.x, -TC.y, TC.expect);
61 accumulate &= test0<S2, S1, Output>(TC.x, TC.y, TC.expect);
62 accumulate &= test0<S2, S1, Output>(-TC.x, TC.y, TC.expect);
63 accumulate &= test0<S2, S1, Output>(TC.x, -TC.y, TC.expect);
64 accumulate &= test0<S2, S1, Output>(-TC.x, -TC.y, TC.expect);
65 }
66 { // test with two unsigned types
67 using Output = std::common_type_t<U1, U2>;
68 accumulate &= test0<U1, U2, Output>(TC.x, TC.y, TC.expect);
69 accumulate &= test0<U2, U1, Output>(TC.x, TC.y, TC.expect);
70 }
71 { // Test with mixed signs
72 using Output = std::common_type_t<S1, U2>;
73 accumulate &= test0<S1, U2, Output>(TC.x, TC.y, TC.expect);
74 accumulate &= test0<U2, S1, Output>(TC.x, TC.y, TC.expect);
75 accumulate &= test0<S1, U2, Output>(-TC.x, TC.y, TC.expect);
76 accumulate &= test0<U2, S1, Output>(TC.x, -TC.y, TC.expect);
77 }
78 { // Test with mixed signs
79 using Output = std::common_type_t<S2, U1>;
80 accumulate &= test0<S2, U1, Output>(TC.x, TC.y, TC.expect);
81 accumulate &= test0<U1, S2, Output>(TC.x, TC.y, TC.expect);
82 accumulate &= test0<S2, U1, Output>(-TC.x, TC.y, TC.expect);
83 accumulate &= test0<U1, S2, Output>(TC.x, -TC.y, TC.expect);
84 }
85 }
86 return accumulate;
87 }
88
main()89 int main()
90 {
91 auto non_cce = std::rand(); // a value that can't possibly be constexpr
92
93 static_assert(do_test<signed char>(), "");
94 static_assert(do_test<short>(), "");
95 static_assert(do_test<int>(), "");
96 static_assert(do_test<long>(), "");
97 static_assert(do_test<long long>(), "");
98
99 assert(do_test<signed char>(non_cce));
100 assert(do_test<short>(non_cce));
101 assert(do_test<int>(non_cce));
102 assert(do_test<long>(non_cce));
103 assert(do_test<long long>(non_cce));
104
105 static_assert(do_test< int8_t>(), "");
106 static_assert(do_test<int16_t>(), "");
107 static_assert(do_test<int32_t>(), "");
108 static_assert(do_test<int64_t>(), "");
109
110 assert(do_test< int8_t>(non_cce));
111 assert(do_test<int16_t>(non_cce));
112 assert(do_test<int32_t>(non_cce));
113 assert(do_test<int64_t>(non_cce));
114
115 static_assert(do_test<signed char, int>(), "");
116 static_assert(do_test<int, signed char>(), "");
117 static_assert(do_test<short, int>(), "");
118 static_assert(do_test<int, short>(), "");
119 static_assert(do_test<int, long>(), "");
120 static_assert(do_test<long, int>(), "");
121 static_assert(do_test<int, long long>(), "");
122 static_assert(do_test<long long, int>(), "");
123
124 assert((do_test<signed char, int>(non_cce)));
125 assert((do_test<int, signed char>(non_cce)));
126 assert((do_test<short, int>(non_cce)));
127 assert((do_test<int, short>(non_cce)));
128 assert((do_test<int, long>(non_cce)));
129 assert((do_test<long, int>(non_cce)));
130 assert((do_test<int, long long>(non_cce)));
131 assert((do_test<long long, int>(non_cce)));
132
133 // LWG#2792
134 {
135 auto res = std::experimental::gcd((int64_t)1234, (int32_t)-2147483648);
136 static_assert( std::is_same<decltype(res), std::common_type<int64_t, int32_t>::type>::value, "");
137 assert(res == 2);
138 }
139 }
140