public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
From: "bugdal at aerifal dot cx" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug ipa/61144] [4.9/4.10 Regression] Invalid optimizations for extern vars with local weak definitions
Date: Tue, 20 May 2014 08:31:00 -0000	[thread overview]
Message-ID: <bug-61144-4-jlMOCZzTio@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-61144-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61144

--- Comment #20 from Rich Felker <bugdal at aerifal dot cx> ---
On further investigation, it looks like the code I cited deals with strong
aliases as well as weak ones, and in the strong alias case, the strong folding
behavior might be desirable. A better fix seems to be adding an explicit check
for weak aliases (DECL_WEAK(decl)) when an alias is found and returning
error_mark_node in that case.

Note that prior to the above-mentioned commit, the !TREE_READONLY(decl) case
was always treated as non-foldable, so there seems to have been no subtlety to
avoiding errors with weak aliases. But the new code performs much more
aggressive constant folding and thus needs to avoid stepping on weak aliases.


  parent reply	other threads:[~2014-05-20  8:31 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-05-11  1:30 [Bug c/61144] New: " bugdal at aerifal dot cx
2014-05-11  3:20 ` [Bug c/61144] " pinskia at gcc dot gnu.org
2014-05-11  3:32 ` bugdal at aerifal dot cx
2014-05-11  3:33 ` bugdal at aerifal dot cx
2014-05-11 19:05 ` bugdal at aerifal dot cx
2014-05-11 19:41 ` pinskia at gcc dot gnu.org
2014-05-11 20:05 ` bugdal at aerifal dot cx
2014-05-12  4:18 ` cloos at jhcloos dot com
2014-05-12 13:23 ` jody at jodybruchon dot com
2014-05-12 13:59 ` cloos at jhcloos dot com
2014-05-12 17:42 ` bugdal at aerifal dot cx
2014-05-12 19:02 ` bugdal at aerifal dot cx
2014-05-12 20:31 ` glisse at gcc dot gnu.org
2014-05-13  3:26 ` bugdal at aerifal dot cx
2014-05-13  8:45 ` glisse at gcc dot gnu.org
2014-05-13 11:19 ` [Bug ipa/61144] [4.9/4.10 Regression] " rguenth at gcc dot gnu.org
2014-05-14  5:08 ` bugdal at aerifal dot cx
2014-05-20  8:31 ` bugdal at aerifal dot cx [this message]
2014-05-20 20:28 ` bugdal at aerifal dot cx
2014-06-26 13:05 ` rguenth at gcc dot gnu.org
2014-06-26 13:36 ` bugdal at aerifal dot cx
2014-07-02 12:23 ` patrick at parcs dot ath.cx
2014-07-02 14:47 ` bugdal at aerifal dot cx
2014-07-14 16:12 ` amonakov at gcc dot gnu.org
2014-07-14 16:13 ` amonakov at gcc dot gnu.org
2014-07-16 13:30 ` jakub at gcc dot gnu.org
2014-07-16 18:17 ` bugdal at aerifal dot cx
2014-07-30  9:14 ` hubicka at gcc dot gnu.org
2014-07-31 22:56 ` bugdal at aerifal dot cx
2014-10-05  4:56 ` [Bug ipa/61144] [4.9/5 " hubicka at gcc dot gnu.org
2014-10-05  4:56 ` hubicka at gcc dot gnu.org
2014-10-05  4:56 ` hubicka at gcc dot gnu.org
2014-10-05  4:58 ` hubicka at gcc dot gnu.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=bug-61144-4-jlMOCZzTio@http.gcc.gnu.org/bugzilla/ \
    --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).