[PATCH][4.3] Deprecate -ftrapv

[Paolo Bonzini]

> Unless printing "This application has requested the Runtime to terminate
> it in an unusual way." counts an issuing a contraint_error in Ada,
> it seems to me that -ftrapv and Ada have differing requirements.
> How can you portabilty and correctly generate a constraint_error if
> the code generated by -ftrapv calls the C runtime function abort()?

The advantage of a GIMPLE implementation would be that you could use a 
langhook to insert the appropriate function call for overflowing 
computation.

> With INTO I don't
> see any way distignuish the SIGSEGV it generates on Linux from any of
> the myriad other ways a SIGSEGV can be generated.

sc.eip == 0xCE (if I remember x86 opcodes well :-) as I'm going by heart...)

That's similar to how Java traps SIGFPEs and transform them to 
zero-divide exceptions, IIRC.

Paolo