signed is undefined and has been since 1992 (in GCC)

[Robert Dewar]

Joe Buck wrote:

> I challenge you, Robert, to find us a C compiler that generates trapping
> instructions for integer adds by default.  I do not believe that such a
> compiler exists.

Probably there is no production compiler that does, MIPS would be the only
possibility I think in practice. Certainly there are checkout debugging
compilers that detect undefined operations.