* Mark Dickinson: > long a, b, x; > ... > x = a + b; > if ((x^a) < 0 && (x^b) < 0) > goto deal_with_overflow; > ... Would this test be better? I think it's equivalent, and it saves a comparison. if (((x ^ a) & (x ^ b)) < 0) > Any suggestions for improvements over this? Use -fwrapv and your first version. > Are there any common C code constructs that gcc would compile to a > jump-on-overflow instruction on x86? I don't think so. Without support throughout GCC, anything in this area (like a builtin) would mostly act as an optimization barrier.
