This is the mail archive of the
gcc@gcc.gnu.org
mailing list for the GCC project.
Re: Ada subtypes and base types
- From: Jeffrey A Law <law at redhat dot com>
- To: Zdenek Dvorak <rakdver at atrey dot karlin dot mff dot cuni dot cz>
- Cc: Sebastian Pop <sebastian dot pop at cri dot ensmp dot fr>, Richard Kenner <kenner at vlsi1 dot ultra dot nyu dot edu>, gcc at gcc dot gnu dot org
- Date: Mon, 27 Feb 2006 11:26:02 -0700
- Subject: Re: Ada subtypes and base types
- References: <20060224184736.GB5239@napoca.cri.ensmp.fr> <20060225084840.GA25639@atrey.karlin.mff.cuni.cz>
- Reply-to: law at redhat dot com
On Sat, 2006-02-25 at 09:48 +0100, Zdenek Dvorak wrote:
> Hello,
>
> > Jeffrey A Law wrote:
> > > Another possibility is to simply not allow conversions between a
> > > subtype and basetype.
> >
> > Such a patch also solves the problem. But I'm not sure to understand
> > the impact on other codes. Is this kind of conversion between a type
> > and its basetype specific to Ada?
>
> this still seems unnecessarily conservative to me. I would just check
> for types whose TYPE_MIN and TYPE_MAX do not match the natural values
> derived from the type precision (i.e., those returned by
> upper_bound_in_type (type, type) and lower_bound_in_type (type, type)).
I doubt it matters in any significant way -- your proposed solution
may allow optimization in a few more cases of Ada code, but at a
compile-time cost (probably not significant).
Either approach is OK with me. I'll probably get one spun completely
today which will hopefully get Ada building again.
jeff