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Re: Ada subtypes and base types

On Fri, 2006-02-24 at 18:42 +0100, Sebastian Pop wrote:
> Richard Kenner wrote:
> >     Just to make sure I've dotted the i's and crossed the t's, this is not
> >     what's happening when we hang in VRP when compiling a-textio.
> > 
> >     We convert the incoming object from natural___XDLU_0___2147483647
> >     into its base type, perform the addition in the base type, then
> >     convert back to XDLU_0_2147483647.
> > 
> > The above is exactly what I thought everybody agrees is and should be
> > happening, so I'm confused by your "this is not what's happening"
> > comment above.
> So if I understand correctly, if we can prove that the operation does
> not overflow in natural___XDLU_0___2147483647, then there is no need
> of a cast to the base type and back.
And that's still a topic that needs to be thoroughly 
discussed.  We overflow the TYPE_MAX_VALUE, but do not
do not cover the set of values allowed by TYPE_PRECISION.

I claim that is a bug in the Ada front-end.  Others might


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