Re: Ada subtypes and base types

[Andrew Pinski <pinskia at physics dot uc dot edu>]

On Mar 21, 2006, at 11:15 AM, Jeffrey A Law wrote:

> On Tue, 2006-03-21 at 10:14 +0100, Duncan Sands wrote:
>
> > Hi Jeff, on the subject of seeing through typecasts, I was playing 
> > around
> > with VRP and noticed that the following "if" statement is not 
> > eliminated:
> >
> > int u (unsigned char c) {
> >         int i = c;
> >
> >         if (i < 0 || i > 255)
> >                 return -1; /* never taken */
> >         else
> >                 return 0;
> > }
> >
> > Is it supposed to be?
> Depends...
>
> The "problem" is the parameter is marked a VR_VARYING (as it
> should be).  Unfortunately, the VR_VARYING source operand prevents
> us from extracting a range for the result of the typecast.


This is also PR 23745.

-- Pinski