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, c++14
11 // <numeric>
12
13 // template<class _M, class _N>
14 // constexpr common_type_t<_M,_N> lcm(_M __m, _N __n)
15
16 #include <numeric>
17 #include <cassert>
18 #include <climits>
19 #include <cstdint>
20 #include <cstdlib>
21 #include <type_traits>
22 #include "test_macros.h"
23
24 constexpr struct {
25 int x;
26 int y;
27 int expect;
28 } Cases[] = {
29 {0, 0, 0},
30 {1, 0, 0},
31 {0, 1, 0},
32 {1, 1, 1},
33 {2, 3, 6},
34 {2, 4, 4},
35 {3, 17, 51},
36 {36, 18, 36}
37 };
38
39 template <typename Input1, typename Input2, typename Output>
test0(int in1,int in2,int out)40 constexpr bool test0(int in1, int in2, int out)
41 {
42 auto value1 = static_cast<Input1>(in1);
43 auto value2 = static_cast<Input2>(in2);
44 static_assert(std::is_same_v<Output, decltype(std::lcm(value1, value2))>, "");
45 static_assert(std::is_same_v<Output, decltype(std::lcm(value2, value1))>, "");
46 assert(static_cast<Output>(out) == std::lcm(value1, value2));
47 return true;
48 }
49
50
51 template <typename Input1, typename Input2 = Input1>
do_test(int=0)52 constexpr bool do_test(int = 0)
53 {
54 using S1 = std::make_signed_t<Input1>;
55 using S2 = std::make_signed_t<Input2>;
56 using U1 = std::make_unsigned_t<Input1>;
57 using U2 = std::make_unsigned_t<Input2>;
58 bool accumulate = true;
59 for (auto TC : Cases) {
60 { // Test with two signed types
61 using Output = std::common_type_t<S1, S2>;
62 accumulate &= test0<S1, S2, Output>(TC.x, TC.y, TC.expect);
63 accumulate &= test0<S1, S2, Output>(-TC.x, TC.y, TC.expect);
64 accumulate &= test0<S1, S2, Output>(TC.x, -TC.y, TC.expect);
65 accumulate &= test0<S1, S2, Output>(-TC.x, -TC.y, TC.expect);
66 accumulate &= test0<S2, S1, Output>(TC.x, TC.y, TC.expect);
67 accumulate &= test0<S2, S1, Output>(-TC.x, TC.y, TC.expect);
68 accumulate &= test0<S2, S1, Output>(TC.x, -TC.y, TC.expect);
69 accumulate &= test0<S2, S1, Output>(-TC.x, -TC.y, TC.expect);
70 }
71 { // test with two unsigned types
72 using Output = std::common_type_t<U1, U2>;
73 accumulate &= test0<U1, U2, Output>(TC.x, TC.y, TC.expect);
74 accumulate &= test0<U2, U1, Output>(TC.x, TC.y, TC.expect);
75 }
76 { // Test with mixed signs
77 using Output = std::common_type_t<S1, U2>;
78 accumulate &= test0<S1, U2, Output>(TC.x, TC.y, TC.expect);
79 accumulate &= test0<U2, S1, Output>(TC.x, TC.y, TC.expect);
80 accumulate &= test0<S1, U2, Output>(-TC.x, TC.y, TC.expect);
81 accumulate &= test0<U2, S1, Output>(TC.x, -TC.y, TC.expect);
82 }
83 { // Test with mixed signs
84 using Output = std::common_type_t<S2, U1>;
85 accumulate &= test0<S2, U1, Output>(TC.x, TC.y, TC.expect);
86 accumulate &= test0<U1, S2, Output>(TC.x, TC.y, TC.expect);
87 accumulate &= test0<S2, U1, Output>(-TC.x, TC.y, TC.expect);
88 accumulate &= test0<U1, S2, Output>(TC.x, -TC.y, TC.expect);
89 }
90 }
91 return accumulate;
92 }
93
main()94 int main()
95 {
96 auto non_cce = std::rand(); // a value that can't possibly be constexpr
97
98 static_assert(do_test<signed char>(), "");
99 static_assert(do_test<short>(), "");
100 static_assert(do_test<int>(), "");
101 static_assert(do_test<long>(), "");
102 static_assert(do_test<long long>(), "");
103
104 assert(do_test<signed char>(non_cce));
105 assert(do_test<short>(non_cce));
106 assert(do_test<int>(non_cce));
107 assert(do_test<long>(non_cce));
108 assert(do_test<long long>(non_cce));
109
110 static_assert(do_test<std::int8_t>(), "");
111 static_assert(do_test<std::int16_t>(), "");
112 static_assert(do_test<std::int32_t>(), "");
113 static_assert(do_test<std::int64_t>(), "");
114
115 assert(do_test<std::int8_t>(non_cce));
116 assert(do_test<std::int16_t>(non_cce));
117 assert(do_test<std::int32_t>(non_cce));
118 assert(do_test<std::int64_t>(non_cce));
119
120 static_assert(do_test<signed char, int>(), "");
121 static_assert(do_test<int, signed char>(), "");
122 static_assert(do_test<short, int>(), "");
123 static_assert(do_test<int, short>(), "");
124 static_assert(do_test<int, long>(), "");
125 static_assert(do_test<long, int>(), "");
126 static_assert(do_test<int, long long>(), "");
127 static_assert(do_test<long long, int>(), "");
128
129 assert((do_test<signed char, int>(non_cce)));
130 assert((do_test<int, signed char>(non_cce)));
131 assert((do_test<short, int>(non_cce)));
132 assert((do_test<int, short>(non_cce)));
133 assert((do_test<int, long>(non_cce)));
134 assert((do_test<long, int>(non_cce)));
135 assert((do_test<int, long long>(non_cce)));
136 assert((do_test<long long, int>(non_cce)));
137
138 // LWG#2837
139 {
140 auto res1 = std::lcm(static_cast<std::int64_t>(1234), INT32_MIN);
141 TEST_IGNORE_NODISCARD std::lcm(INT_MIN, 2UL); // this used to trigger UBSAN
142 static_assert(std::is_same_v<decltype(res1), std::int64_t>, "");
143 assert(res1 == 1324997410816LL);
144 }
145 }
146