value range propagation for logical OR

Sat Apr 10 10:22:40 PDT 2010

On Sat, 10 Apr 2010 12:01:45 -0500, Andrei Alexandrescu 
<SeeWebsiteForEmail at erdani.org> wrote:
> 
> Consider:
> 
> byte c = a | b;
> 
> Say you already know min_a, max_a, min_b, and max_b. How do you compute 
> min_c and max_c? I thought of it for a bit and it seems quite tricky.
> 
> 
> Thanks,
> 
> Andrei

It seems like it would use the lowest minimum and the highest maximum of 
the two... that's what I personally would find most natural, given the 
semantics of bitwise OR, but maybe I'm just way off base.