gcd.pass.cpp (5165B)
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 12 // <numeric> 13 14 // template<class _M, class _N> 15 // constexpr common_type_t<_M,_N> gcd(_M __m, _N __n) 16 17 #include <numeric> 18 #include <cassert> 19 #include <climits> 20 #include <cstdint> 21 #include <cstdlib> // for rand() 22 #include <type_traits> 23 24 constexpr struct { 25 int x; 26 int y; 27 int expect; 28 } Cases[] = { 29 {0, 0, 0}, 30 {1, 0, 1}, 31 {0, 1, 1}, 32 {1, 1, 1}, 33 {2, 3, 1}, 34 {2, 4, 2}, 35 {36, 17, 1}, 36 {36, 18, 18} 37 }; 38 39 40 template <typename Input1, typename Input2, typename Output> 41 constexpr bool test0(int in1, int in2, int out) 42 { 43 auto value1 = static_cast<Input1>(in1); 44 auto value2 = static_cast<Input2>(in2); 45 static_assert(std::is_same_v<Output, decltype(std::gcd(value1, value2))>, ""); 46 static_assert(std::is_same_v<Output, decltype(std::gcd(value2, value1))>, ""); 47 assert(static_cast<Output>(out) == std::gcd(value1, value2)); 48 return true; 49 } 50 51 52 template <typename Input1, typename Input2 = Input1> 53 constexpr bool do_test(int = 0) 54 { 55 using S1 = std::make_signed_t<Input1>; 56 using S2 = std::make_signed_t<Input2>; 57 using U1 = std::make_unsigned_t<Input1>; 58 using U2 = std::make_unsigned_t<Input2>; 59 bool accumulate = true; 60 for (auto TC : Cases) { 61 { // Test with two signed types 62 using Output = std::common_type_t<S1, S2>; 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<S1, S2, 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 accumulate &= test0<S2, S1, Output>(-TC.x, -TC.y, TC.expect); 71 } 72 { // test with two unsigned types 73 using Output = std::common_type_t<U1, U2>; 74 accumulate &= test0<U1, U2, Output>(TC.x, TC.y, TC.expect); 75 accumulate &= test0<U2, U1, Output>(TC.x, TC.y, TC.expect); 76 } 77 { // Test with mixed signs 78 using Output = std::common_type_t<S1, U2>; 79 accumulate &= test0<S1, U2, Output>(TC.x, TC.y, TC.expect); 80 accumulate &= test0<U2, S1, Output>(TC.x, TC.y, TC.expect); 81 accumulate &= test0<S1, U2, Output>(-TC.x, TC.y, TC.expect); 82 accumulate &= test0<U2, S1, Output>(TC.x, -TC.y, TC.expect); 83 } 84 { // Test with mixed signs 85 using Output = std::common_type_t<S2, U1>; 86 accumulate &= test0<S2, U1, Output>(TC.x, TC.y, TC.expect); 87 accumulate &= test0<U1, S2, Output>(TC.x, TC.y, TC.expect); 88 accumulate &= test0<S2, U1, Output>(-TC.x, TC.y, TC.expect); 89 accumulate &= test0<U1, S2, Output>(TC.x, -TC.y, TC.expect); 90 } 91 } 92 return accumulate; 93 } 94 95 int main() 96 { 97 auto non_cce = std::rand(); // a value that can't possibly be constexpr 98 99 static_assert(do_test<signed char>(), ""); 100 static_assert(do_test<short>(), ""); 101 static_assert(do_test<int>(), ""); 102 static_assert(do_test<long>(), ""); 103 static_assert(do_test<long long>(), ""); 104 105 assert(do_test<signed char>(non_cce)); 106 assert(do_test<short>(non_cce)); 107 assert(do_test<int>(non_cce)); 108 assert(do_test<long>(non_cce)); 109 assert(do_test<long long>(non_cce)); 110 111 static_assert(do_test<std::int8_t>(), ""); 112 static_assert(do_test<std::int16_t>(), ""); 113 static_assert(do_test<std::int32_t>(), ""); 114 static_assert(do_test<std::int64_t>(), ""); 115 116 assert(do_test<std::int8_t>(non_cce)); 117 assert(do_test<std::int16_t>(non_cce)); 118 assert(do_test<std::int32_t>(non_cce)); 119 assert(do_test<std::int64_t>(non_cce)); 120 121 static_assert(do_test<signed char, int>(), ""); 122 static_assert(do_test<int, signed char>(), ""); 123 static_assert(do_test<short, int>(), ""); 124 static_assert(do_test<int, short>(), ""); 125 static_assert(do_test<int, long>(), ""); 126 static_assert(do_test<long, int>(), ""); 127 static_assert(do_test<int, long long>(), ""); 128 static_assert(do_test<long long, int>(), ""); 129 130 assert((do_test<signed char, int>(non_cce))); 131 assert((do_test<int, signed char>(non_cce))); 132 assert((do_test<short, int>(non_cce))); 133 assert((do_test<int, short>(non_cce))); 134 assert((do_test<int, long>(non_cce))); 135 assert((do_test<long, int>(non_cce))); 136 assert((do_test<int, long long>(non_cce))); 137 assert((do_test<long long, int>(non_cce))); 138 139 // LWG#2837 140 { 141 auto res = std::gcd(static_cast<std::int64_t>(1234), INT32_MIN); 142 static_assert(std::is_same_v<decltype(res), std::int64_t>, ""); 143 assert(res == 2); 144 } 145 }