1 // PR c++/70507 - integer overflow builtins not constant expressions 2 // The constexpr-arith-overflow.C testcase covers this for C++14 and later. 3 // { dg-do compile } 4 // { dg-options "-std=c++11" } 5 6 #define Assert(expr) static_assert ((expr), #expr) 7 8 template <class T> 9 constexpr T add (T x, T y, T z = T ()) 10 { 11 return __builtin_add_overflow (x, y, &z) ? 0 : z; // { dg-error "is not a constant expression" } 12 } 13 14 template <class T> 15 constexpr T sub (T x, T y, T z = T ()) 16 { 17 return __builtin_sub_overflow (x, y, &z) ? 0 : z; // { dg-error "is not a constant expression" } 18 } 19 20 template <class T> 21 constexpr T mul (T x, T y, T z = T ()) 22 { 23 return __builtin_mul_overflow (x, y, &z) ? 0 : z; // { dg-error "is not a constant expression" } 24 } 25 26 Assert (0 == add<int>(0, 0)); // { dg-error "non-constant condition for static assertion" } 27 Assert (0 == sub<int>(0, 0)); // { dg-error "non-constant condition for static assertion" } 28 Assert (0 == mul<int>(0, 0)); // { dg-error "non-constant condition for static assertion" } 29 // { dg-message "expansion of" "" { target *-*-* } .-3 } 30 // { dg-message "expansion of" "" { target *-*-* } .-3 } 31 // { dg-message "expansion of" "" { target *-*-* } .-3 } 32