This is the mail archive of the
mailing list for the GCC project.
Re: Modes on CONST_INTs
- To: hans-peter dot nilsson at axis dot com
- Subject: Re: Modes on CONST_INTs
- From: Geoff Keating <geoffk at geoffk dot org>
- Date: Sun, 26 Nov 2000 13:01:54 -0800
- CC: bernds at redhat dot com, gcc at gcc dot gnu dot org
- References: <200011261419.PAA16592@ignucius.axis.se>
- Reply-to: Geoff Keating <geoffk at redhat dot com>
> Date: Sun, 26 Nov 2000 15:19:43 +0100
> From: Hans-Peter Nilsson <firstname.lastname@example.org>
> CC: email@example.com, firstname.lastname@example.org
> > Date: Fri, 24 Nov 2000 10:06:08 +0000 (GMT)
> > From: Bernd Schmidt <email@example.com>
> > It seems that every now and then, we run into bugs involving a lack of mode
> > information on CONST_INTs. So far everyone I've asked has agreed that we
> > really should have a mode for constants, but no one ever bothered because the
> > change is going to be huge.
> > Even if the change is going to be huge, I don't see how it can be any more
> > painful than the recurring problems we have because of the lack of mode
> > information. So, I'm looking for viable ways to gradually transform the
> > compiler towards using modes on constants.
> > Any comments?
> Here's an "any-comment":
> I was going in the direction of canonicalizing CONST_INTs by
> sign-extension, as indicated by Geoff in response to a recent
> patch of mine. Perhaps that would solve those problems with a
> smaller change than caring for an associated mode with each
> constant; it doesn't seem like there are a large enough amount
> of failing codes and test-cases to warrant such a huge change.
These are orthogonal. You still have to fix canonicalization
even if you have the mode information. Having a mode may make this
easier; you can certainly find any bugs in the canonicalization much faster.
- Geoffrey Keating <firstname.lastname@example.org>