public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
From: "law at redhat dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/15248] [4.0 Regression] Reload may generate stores to read-only memory
Date: Tue, 17 May 2005 17:04:00 -0000 [thread overview]
Message-ID: <20050517170354.5267.qmail@sourceware.org> (raw)
In-Reply-To: <20040502130145.15248.ebotcazou@gcc.gnu.org>
------- Additional Comments From law at redhat dot com 2005-05-17 17:03 -------
Subject: Re: [4.0 Regression] Reload may
generate stores to read-only memory
On Sat, 2005-05-07 at 16:52 +0000, ebotcazou at gcc dot gnu dot org
wrote:
> ------- Additional Comments From ebotcazou at gcc dot gnu dot org 2005-05-07 16:52 -------
> > I don't know that I'm in a position to make a good decision here, but I
> > do agree with Jeff -- it would be a lot more compelling to make the
> > change if there was actually a demonstrable problem -- especially coming
> > from non-synthetic code.
>
> I presume you'd like to have a testcase that fails with 4.0.x? Because I can
> hardly think of a more demonstrable problem than this one: Jeff's analysis for
> 4.1.x was exactly the same as mine for 3.3.x and nothing has changed in the code.
It's still a relatively difficult bug to tickle. It only appeared in
the mainline as a side effect of improvements to the jump threading code
Block duplication followed by redundancy elimination resulted in having
a pseudo-pseudo copy where the source pseudo was equivalent to a
readonly mem and the RTL optimizers did not eliminate the pseudo-pseudo
copy.
Bernd has done some additional work on this problem and we may be
converging on a better solution than simply ignoring these problematical
equivalences.
Jeff
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15248
next prev parent reply other threads:[~2005-05-17 17:04 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-05-02 13:01 [Bug optimization/15248] New: " ebotcazou at gcc dot gnu dot org
2004-05-02 14:04 ` [Bug optimization/15248] " pinskia at gcc dot gnu dot org
2004-09-17 10:38 ` [Bug rtl-optimization/15248] " steven at gcc dot gnu dot org
2004-09-19 13:13 ` ebotcazou at gcc dot gnu dot org
2005-01-31 6:52 ` pinskia at gcc dot gnu dot org
2005-04-19 6:54 ` ebotcazou at gcc dot gnu dot org
2005-04-19 10:04 ` [Bug rtl-optimization/15248] [4.0/4.1 Regression] " giovannibajo at libero dot it
2005-04-20 17:05 ` ebotcazou at gcc dot gnu dot org
2005-04-30 22:10 ` [Bug rtl-optimization/15248] [4.0 " ebotcazou at gcc dot gnu dot org
2005-05-03 19:25 ` law at redhat dot com
2005-05-03 19:35 ` mark at codesourcery dot com
2005-05-07 16:52 ` ebotcazou at gcc dot gnu dot org
2005-05-09 0:20 ` mark at codesourcery dot com
2005-05-17 17:04 ` law at redhat dot com [this message]
2005-07-06 16:41 ` mmitchel at gcc dot gnu dot org
2005-07-06 16:48 ` law at redhat dot com
2005-07-07 10:19 ` ebotcazou at gcc dot gnu dot org
2005-08-18 9:51 ` bonzini at gcc dot gnu dot org
2005-08-22 16:47 ` mmitchel at gcc dot gnu dot org
2005-08-29 15:05 ` bonzini at gcc dot gnu dot org
2005-08-29 15:16 ` cvs-commit at gcc dot gnu dot org
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=20050517170354.5267.qmail@sourceware.org \
--to=gcc-bugzilla@gcc.gnu.org \
--cc=gcc-bugs@gcc.gnu.org \
/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).