[PATCH][4.3] Deprecate -ftrapv

[Florian Weimer]

* Richard Kenner:

>> int f(int a, int b) { return 0 * (a + b); }
>> 
>> get the potentially trapping arithmetic folded away.  If -ftrapv is to 
>> have properly defined semantics, those must include trapping if (a + b) 
>> overflows in the above code.
>
> Why?  Is there any language that requires such semantics?

Standard ML.  I don't think there is a GCC front end (and it's not
likely that one will be feasible, at least until GCC supports a fitting
garbage collector).