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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/49872] Missed optimization: Could coalesce neighboring memsets
Date: Thu, 28 Jul 2011 10:01:00 -0000 [thread overview]
Message-ID: <bug-49872-4-kOhbyRrYSh@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-49872-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49872
Richard Guenther <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2011.07.28 10:00:34
Ever Confirmed|0 |1
--- Comment #1 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-07-28 10:00:34 UTC ---
Confirmed.
It should be hard to implement this, but did you see this in real-world code
(to asses the importance of this optimization)?
Other cases would include (partially) overlapping memsets (or related
functions such as memory copying routines and the respective string variants).
We already optimize some cases (that appeared in GCC IIRC) in
tree-ssa-forwprop.c,
namely
/* *GSI_P is a GIMPLE_CALL to a builtin function.
Optimize
memcpy (p, "abcd", 4);
memset (p + 4, ' ', 3);
into
memcpy (p, "abcd ", 7);
call if the latter can be stored by pieces during expansion. */
next prev parent reply other threads:[~2011-07-28 10:01 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-27 16:51 [Bug tree-optimization/49872] New: " sgunderson at bigfoot dot com
2011-07-28 10:01 ` rguenth at gcc dot gnu.org [this message]
2011-07-28 10:10 ` [Bug tree-optimization/49872] " sgunderson at bigfoot dot com
2021-08-21 23:57 ` pinskia at gcc dot gnu.org
2024-04-21 19:26 ` pinskia at gcc dot gnu.org
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