public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
From: "glisse at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/57742] memset(malloc(n),0,n) -> calloc(n,1)
Date: Mon, 14 Oct 2013 11:48:00 -0000 [thread overview]
Message-ID: <bug-57742-4-qcrmd8Yk2y@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-57742-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57742
--- Comment #6 from Marc Glisse <glisse at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #5)
> We have walk_aliased_vdefs for this. Basically the first callback
> you receive has to be the malloc, otherwise there is an aliasing
> stmt inbetween.
Cool! Last time I looked into a similar optimization, I needed to look also at
the memory reads, not just the writes, so it was significantly more
complicated. walk_aliased_vdefs looks perfect here, both for malloc+memset
where there is nothing to read before the memset, and for calloc+memset where
reading before or after the memset returns the same :-)
next prev parent reply other threads:[~2013-10-14 11:48 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-27 22:28 [Bug tree-optimization/57742] New: " glisse at gcc dot gnu.org
2013-10-11 16:44 ` [Bug tree-optimization/57742] " glisse at gcc dot gnu.org
2013-10-14 8:55 ` rguenth at gcc dot gnu.org
2013-10-14 9:51 ` Joost.VandeVondele at mat dot ethz.ch
2013-10-14 10:07 ` glisse at gcc dot gnu.org
2013-10-14 10:46 ` rguenth at gcc dot gnu.org
2013-10-14 11:48 ` glisse at gcc dot gnu.org [this message]
2013-10-14 20:51 ` glisse at gcc dot gnu.org
2013-10-14 20:53 ` glisse at gcc dot gnu.org
2013-10-15 7:57 ` rguenth at gcc dot gnu.org
2013-10-15 14:11 ` glisse at gcc dot gnu.org
2013-10-15 16:38 ` glisse at gcc dot gnu.org
2013-10-16 14:11 ` rguenth at gcc dot gnu.org
2014-02-22 15:44 ` glisse at gcc dot gnu.org
2014-02-23 18:46 ` glisse at gcc dot gnu.org
2014-06-24 19:04 ` glisse at gcc dot gnu.org
2014-06-25 6:46 ` Joost.VandeVondele at mat dot ethz.ch
2014-06-25 7:41 ` Joost.VandeVondele at mat dot ethz.ch
2014-06-25 7:53 ` glisse at gcc dot gnu.org
2014-06-25 8:09 ` glisse at gcc dot gnu.org
2014-06-25 12:27 ` glisse at gcc dot gnu.org
2014-06-25 12:29 ` glisse at gcc dot gnu.org
2015-09-17 19:32 ` daniel.gutson at tallertechnologies dot com
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-57742-4-qcrmd8Yk2y@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).