| // { dg-do compile { target c++17 } } |
| #include <numeric> |
| #include <climits> |
| |
| // PR libstdc++/105844 |
| |
| // |INT_MIN| can be represented in common_type_t<int, unsigned> i.e. unsigned. |
| static_assert( std::lcm(INT_MIN, 1u) == INT_MAX+1u ); |
| static_assert( std::lcm(1u, INT_MIN) == INT_MAX+1u ); |
| |
| // But |INT_MIN| cannot be represented in common_type<int, int> i.e. int. |
| constexpr int a = std::lcm(INT_MIN, 1); // { dg-error "overflow" } |
| constexpr int b = std::lcm(1, INT_MIN); // { dg-error "overflow" } |
| |
| // And the LCM of 50000 and 49999 cannot be represented in int. |
| constexpr int c = std::lcm(50000, 49999); // { dg-error "overflow" } |
| constexpr int d = std::lcm(49999, 50000); // { dg-error "overflow" } |
| |
| // Similarly for unsigned, but the diagnostic is a failed assertion instead. |
| constexpr int e = std::lcm(500000u, 499999); // { dg-error "in 'constexpr'" } |
| constexpr int f = std::lcm(499999u, 500000); // { dg-error "in 'constexpr'" } |
| // { dg-error "unreachable" "" { target *-*-* } 0 } |
