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Re: RFC: kill ORIGINAL_REGNO
- From: Michael Matz <matz at suse dot de>
- To: Richard Henderson <rth at redhat dot com>
- Cc: Steven Bosscher <stevenb at suse dot de>, gcc-patches at gcc dot gnu dot org
- Date: Mon, 3 May 2004 08:42:03 +0200 (CEST)
- Subject: Re: RFC: kill ORIGINAL_REGNO
- References: <6620348.1083061867030.SLOX.WebMail.firstname.lastname@example.org><4837279.1083073939743.SLOX.WebMail.email@example.com><20040430033855.GH500@redhat.com>
On Thu, 29 Apr 2004, Richard Henderson wrote:
> On Tue, Apr 27, 2004 at 03:52:19PM +0200, Steven Bosscher wrote:
> > In the only major ORIGINAL_REGNO user, regrename.c, we seem to be only
> > interested in testing if ORIGINAL_REGNO (reg) == REGNO (reg), in which
> > case it must have been a hard reg from an asm statement.
> I think originally this was going to be used for var-tracking,
> but that wound up inventing a new REG_ATTRS thing instead.
> Patch is ok if it passes regression testing, and builds cc1 for
> all targets touched.
Um. This makes the dumps after reload harder to read. Sometimes by much.
I remember the times when there was no ORIGINAL_REGNO and also remember
the joy I felt once they were there (in fact at that time I even thought
it was specifically invented for debugging dumps).
Steven's "but IMHO one can just read the RTL dumps to see what happened"
is a tautology.
So, I think this behaviour should be preserved, maybe by moving it to the
REG_ATTRS, no idea.