1 //===----------------------------------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // UNSUPPORTED: c++03, c++11, c++14 10 11 // <numeric> 12 13 // template<class _M, class _N> 14 // constexpr common_type_t<_M,_N> gcd(_M __m, _N __n) 15 16 #include <numeric> 17 #include <cassert> 18 #include <climits> 19 #include <cstdint> 20 #include <cstdlib> // for rand() 21 #include <type_traits> 22 23 #include "test_macros.h" 24 25 constexpr struct { 26 int x; 27 int y; 28 int expect; 29 } Cases[] = { 30 {0, 0, 0}, 31 {1, 0, 1}, 32 {0, 1, 1}, 33 {1, 1, 1}, 34 {2, 3, 1}, 35 {2, 4, 2}, 36 {36, 17, 1}, 37 {36, 18, 18} 38 }; 39 40 41 template <typename Input1, typename Input2, typename Output> 42 constexpr bool test0(int in1, int in2, int out) 43 { 44 auto value1 = static_cast<Input1>(in1); 45 auto value2 = static_cast<Input2>(in2); 46 static_assert(std::is_same_v<Output, decltype(std::gcd(value1, value2))>, ""); 47 static_assert(std::is_same_v<Output, decltype(std::gcd(value2, value1))>, ""); 48 assert(static_cast<Output>(out) == std::gcd(value1, value2)); 49 return true; 50 } 51 52 53 template <typename Input1, typename Input2 = Input1> 54 constexpr bool do_test(int = 0) 55 { 56 using S1 = std::make_signed_t<Input1>; 57 using S2 = std::make_signed_t<Input2>; 58 using U1 = std::make_unsigned_t<Input1>; 59 using U2 = std::make_unsigned_t<Input2>; 60 bool accumulate = true; 61 for (auto TC : Cases) { 62 { // Test with two signed types 63 using Output = std::common_type_t<S1, S2>; 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<S1, S2, Output>(TC.x, -TC.y, TC.expect); 67 accumulate &= test0<S1, S2, 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 accumulate &= test0<S2, S1, Output>(TC.x, -TC.y, TC.expect); 71 accumulate &= test0<S2, S1, Output>(-TC.x, -TC.y, TC.expect); 72 } 73 { // test with two unsigned types 74 using Output = std::common_type_t<U1, U2>; 75 accumulate &= test0<U1, U2, Output>(TC.x, TC.y, TC.expect); 76 accumulate &= test0<U2, U1, Output>(TC.x, TC.y, TC.expect); 77 } 78 { // Test with mixed signs 79 using Output = std::common_type_t<S1, U2>; 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 accumulate &= test0<S1, U2, Output>(-TC.x, TC.y, TC.expect); 83 accumulate &= test0<U2, S1, Output>(TC.x, -TC.y, TC.expect); 84 } 85 { // Test with mixed signs 86 using Output = std::common_type_t<S2, U1>; 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 accumulate &= test0<S2, U1, Output>(-TC.x, TC.y, TC.expect); 90 accumulate &= test0<U1, S2, Output>(TC.x, -TC.y, TC.expect); 91 } 92 } 93 return accumulate; 94 } 95 96 int main(int, char**) 97 { 98 auto non_cce = std::rand(); // a value that can't possibly be constexpr 99 100 static_assert(do_test<signed char>(), ""); 101 static_assert(do_test<short>(), ""); 102 static_assert(do_test<int>(), ""); 103 static_assert(do_test<long>(), ""); 104 static_assert(do_test<long long>(), ""); 105 106 assert(do_test<signed char>(non_cce)); 107 assert(do_test<short>(non_cce)); 108 assert(do_test<int>(non_cce)); 109 assert(do_test<long>(non_cce)); 110 assert(do_test<long long>(non_cce)); 111 112 static_assert(do_test<std::int8_t>(), ""); 113 static_assert(do_test<std::int16_t>(), ""); 114 static_assert(do_test<std::int32_t>(), ""); 115 static_assert(do_test<std::int64_t>(), ""); 116 117 assert(do_test<std::int8_t>(non_cce)); 118 assert(do_test<std::int16_t>(non_cce)); 119 assert(do_test<std::int32_t>(non_cce)); 120 assert(do_test<std::int64_t>(non_cce)); 121 122 static_assert(do_test<signed char, int>(), ""); 123 static_assert(do_test<int, signed char>(), ""); 124 static_assert(do_test<short, int>(), ""); 125 static_assert(do_test<int, short>(), ""); 126 static_assert(do_test<int, long>(), ""); 127 static_assert(do_test<long, int>(), ""); 128 static_assert(do_test<int, long long>(), ""); 129 static_assert(do_test<long long, int>(), ""); 130 131 assert((do_test<signed char, int>(non_cce))); 132 assert((do_test<int, signed char>(non_cce))); 133 assert((do_test<short, int>(non_cce))); 134 assert((do_test<int, short>(non_cce))); 135 assert((do_test<int, long>(non_cce))); 136 assert((do_test<long, int>(non_cce))); 137 assert((do_test<int, long long>(non_cce))); 138 assert((do_test<long long, int>(non_cce))); 139 140 // LWG#2837 141 { 142 auto res = std::gcd(static_cast<std::int64_t>(1234), INT32_MIN); 143 static_assert(std::is_same_v<decltype(res), std::int64_t>, ""); 144 assert(res == 2); 145 } 146 147 return 0; 148 } 149