public inbox for gcc@gcc.gnu.org
 help / color / mirror / Atom feed
From: David Edelsohn <dje@watson.ibm.com>
To: Geoffrey KEATING <geoffk@discus.anu.edu.au>
Cc: egcs@cygnus.com
Subject: Re: asm clobbers, !SMALL_REGISTER_CLASSES patch.
Date: Thu, 12 Feb 1998 20:24:00 -0000	[thread overview]
Message-ID: <9802130410.AA27074@rios1.watson.ibm.com> (raw)
In-Reply-To: <199802130301.OAA15403@discus.anu.edu.au>

        * stmt.c (expand_asm_operands): When an asm statement
        clobbers a register that is in a class of its own, and there
        is space remaining for an extra output, turn the clobber into
        an output to a dummy pseudo.  At present, don't do this if
        there are constraints that have alternatives.

	This is a good effort and I am glad that you are continuing to
pursue this needed feature, but I am curious why you are choosing to
implement it this way instead of as a match_scratch of the appropriate
register class?  I think that the correct solution is to turn the clobber
of a named register into the equivalent that GCC uses internally for
machine description files: match_scratch.  This patch probably works to
some extent, but it simply lies to GCC by transforming the clobber -- and
lying to GCC always causes problems in the long run.

David


  reply	other threads:[~1998-02-12 20:24 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
1998-02-12 19:36 Geoffrey KEATING
1998-02-12 20:24 ` David Edelsohn [this message]
1998-02-12 20:24   ` Geoffrey KEATING
1998-02-13  2:28   ` Richard Henderson
1998-02-13 10:34     ` David Edelsohn
1998-02-13 10:58       ` Richard Henderson
1998-02-13 10:58         ` David Edelsohn
1998-02-14 20:23         ` Geoffrey KEATING
1998-02-13  2:28   ` Jeffrey A Law
1998-02-13  2:28     ` Geoffrey KEATING
1998-02-14  0:32       ` Jeffrey A Law
1998-02-14 21:14         ` Geoffrey KEATING
1998-02-15 11:33           ` Jeffrey A Law
1998-02-15 18:47             ` David Edelsohn

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=9802130410.AA27074@rios1.watson.ibm.com \
    --to=dje@watson.ibm.com \
    --cc=egcs@cygnus.com \
    --cc=geoffk@discus.anu.edu.au \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).