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 <cstdlib> // for rand() 20 #include <iostream> 21 22 constexpr struct { 23 int x; 24 int y; 25 int expect; 26 } Cases[] = { 27 {0, 0, 0}, 28 {1, 0, 1}, 29 {0, 1, 1}, 30 {1, 1, 1}, 31 {2, 3, 1}, 32 {2, 4, 2}, 33 {36, 17, 1}, 34 {36, 18, 18} 35 }; 36 37 38 template <typename Input1, typename Input2, typename Output> 39 constexpr bool test0(Input1 in1, Input2 in2, Output out) 40 { 41 static_assert((std::is_same<Output, decltype(std::gcd(in1, in2))>::value), "" ); 42 static_assert((std::is_same<Output, decltype(std::gcd(in2, in1))>::value), "" ); 43 return out == std::gcd(in1, in2) ? true : (std::abort(), false); 44 } 45 46 47 template <typename Input1, typename Input2 = Input1> 48 constexpr bool do_test(int = 0) 49 { 50 using S1 = typename std::make_signed<Input1>::type; 51 using S2 = typename std::make_signed<Input2>::type; 52 using U1 = typename std::make_unsigned<Input1>::type; 53 using U2 = typename std::make_unsigned<Input2>::type; 54 bool accumulate = true; 55 for (auto TC : Cases) { 56 { // Test with two signed types 57 using Output = std::common_type_t<S1, S2>; 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<S1, S2, 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 accumulate &= test0<S2, S1, Output>(-TC.x, -TC.y, TC.expect); 66 } 67 { // test with two unsigned types 68 using Output = std::common_type_t<U1, U2>; 69 accumulate &= test0<U1, U2, Output>(TC.x, TC.y, TC.expect); 70 accumulate &= test0<U2, U1, Output>(TC.x, TC.y, TC.expect); 71 } 72 { // Test with mixed signs 73 using Output = std::common_type_t<S1, U2>; 74 accumulate &= test0<S1, U2, Output>(TC.x, TC.y, TC.expect); 75 accumulate &= test0<U2, S1, Output>(TC.x, TC.y, TC.expect); 76 accumulate &= test0<S1, U2, Output>(-TC.x, TC.y, TC.expect); 77 accumulate &= test0<U2, S1, Output>(TC.x, -TC.y, TC.expect); 78 } 79 { // Test with mixed signs 80 using Output = std::common_type_t<S2, U1>; 81 accumulate &= test0<S2, U1, Output>(TC.x, TC.y, TC.expect); 82 accumulate &= test0<U1, S2, Output>(TC.x, TC.y, TC.expect); 83 accumulate &= test0<S2, U1, Output>(-TC.x, TC.y, TC.expect); 84 accumulate &= test0<U1, S2, Output>(TC.x, -TC.y, TC.expect); 85 } 86 } 87 return accumulate; 88 } 89 90 int main() 91 { 92 auto non_cce = std::rand(); // a value that can't possibly be constexpr 93 94 static_assert(do_test<signed char>(), ""); 95 static_assert(do_test<short>(), ""); 96 static_assert(do_test<int>(), ""); 97 static_assert(do_test<long>(), ""); 98 static_assert(do_test<long long>(), ""); 99 100 assert(do_test<signed char>(non_cce)); 101 assert(do_test<short>(non_cce)); 102 assert(do_test<int>(non_cce)); 103 assert(do_test<long>(non_cce)); 104 assert(do_test<long long>(non_cce)); 105 106 static_assert(do_test< int8_t>(), ""); 107 static_assert(do_test<int16_t>(), ""); 108 static_assert(do_test<int32_t>(), ""); 109 static_assert(do_test<int64_t>(), ""); 110 111 assert(do_test< int8_t>(non_cce)); 112 assert(do_test<int16_t>(non_cce)); 113 assert(do_test<int32_t>(non_cce)); 114 assert(do_test<int64_t>(non_cce)); 115 116 static_assert(do_test<signed char, int>(), ""); 117 static_assert(do_test<int, signed char>(), ""); 118 static_assert(do_test<short, int>(), ""); 119 static_assert(do_test<int, short>(), ""); 120 static_assert(do_test<int, long>(), ""); 121 static_assert(do_test<long, int>(), ""); 122 static_assert(do_test<int, long long>(), ""); 123 static_assert(do_test<long long, int>(), ""); 124 125 assert((do_test<signed char, int>(non_cce))); 126 assert((do_test<int, signed char>(non_cce))); 127 assert((do_test<short, int>(non_cce))); 128 assert((do_test<int, short>(non_cce))); 129 assert((do_test<int, long>(non_cce))); 130 assert((do_test<long, int>(non_cce))); 131 assert((do_test<int, long long>(non_cce))); 132 assert((do_test<long long, int>(non_cce))); 133 134 // LWG#2837 135 { 136 auto res = std::gcd((int64_t)1234, (int32_t)-2147483648); 137 static_assert( std::is_same<decltype(res), std::common_type<int64_t, int32_t>::type>::value, ""); 138 assert(res == 2); 139 } 140 } 141