Re: [PATCH 2/3] Simplify wrapped binops

[Marc Glisse <marc dot glisse at inria dot fr>]

On Wed, 5 Jul 2017, Robin Dapp wrote:

> > While the initialization value doesn't matter (wi::add will overwrite it)
> > better initialize both to false ;)  Ah, you mean because we want to
> > transform only if get_range_info returned VR_RANGE.  Indeed somewhat
> > unintuitive (but still the best variant for now).
>
> > so I'm still missing a comment on why min_ovf && max_ovf is ok.
> > The simple-minded would have written [...]
>
> I suppose it's more a matter of considering too many things at the same
> time for me...  I was still thinking of including more cases than
> necessary for the regression.  Guess the attached version will do as
> well and should not contain any more surprises.  If needed, I'll add
> additional cases some time.

What happens for (long)(X+10)+LONG_MAX where X has type int and is in 
[-30, -20]? It looks like wi::add will overflow and you will generate 
X+negative which overflows at runtime.

(It looks like you don't need to name @3, you could just use the type of 
@0 instead)

--
Marc Glisse