Ada front-end depends on signed overflow

[Florian Weimer]

* Paul Schlie:

>> No they should be using -ftrapv instead which traps on overflow and then
>> make sure they are not trapping when testing.
>
> - why? what language or who's code/target ever expects such a behavior?

I think Andrew wants programmers to fix their code, instead of
papering over problems. 8-)

All code has seen wide testing essentially with -fwrapv enabled
because in previous GCC version, -fwrapv had only a limited effect,
especially across multiple statmeents.  That's why I don't prefer the
-ftrapv approach, even though its technically the correct one.

It's a real pity that we have to trust so much C code which has been
written and reviewed by developers who aren't aware that signed
integer overflow is undefined.