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Re: [patch] for PRs 27639 and 26719
- From: Duncan Sands <duncan dot sands at math dot u-psud dot fr>
- To: gcc-patches at gcc dot gnu dot org
- Cc: Richard Kenner <kenner at vlsi1 dot ultra dot nyu dot edu>, iant at google dot com, ebotcazou at adacore dot com, rakdver at atrey dot karlin dot mff dot cuni dot cz, rguenther at suse dot de, sebastian dot pop at cri dot ensmp dot fr
- Date: Fri, 7 Jul 2006 13:28:27 +0200
- Subject: Re: [patch] for PRs 27639 and 26719
- References: <20060520192624.GA28713@atrey.karlin.mff.cuni.cz> <m3irmb93bh.fsf@dhcp-172-18-108-216.corp.google.com> <10607061338.AA21654@vlsi1.ultra.nyu.edu>
On Thursday 6 July 2006 15:38, Richard Kenner wrote:
> > It would be nice if somebody could write down the rules for subtypes
> > of INTEGER_TYPE. As far as I know they are undocumented.
>
> Can you say what type of information you're looking for? My view has always
> been that they follow the standard rules of all types, with nothing special
> going on. Some languages have rules regarding in which types arithmetic
> is done, but those are necessarily language-specific.
For VRP, it would be helpful to have an efficient way of checking whether
TYPE_MIN_VAL/TYPE_MAX_VAL are [*] non-trivial for a type, i.e. differ from
what you might expect given TYPE_PRECISION and signedness. Perhaps you can
suggest one?
Thanks,
Duncan.
[*] this should probably read: "may be non-trivial", since they can not
always be determined at compile time (dynamic ranges).