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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/44281] [4.3/4.4/4.5/4.6 Regression] Global Register variable pessimisation
Date: Fri, 04 Mar 2011 11:23:00 -0000	[thread overview]
Message-ID: <bug-44281-4-ANmFrzdcWN@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-44281-4@http.gcc.gnu.org/bugzilla/>

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44281

--- Comment #9 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-03-04 11:22:51 UTC ---
You are talking about this single testcase, I'm talking in general that if gcc
is on x86_64 tuned for a medium sized general purpose register file and you
suddenly turn it into a very limited size general purpose register file, you
can get non-optimal code.  Such bugreports are definitely much lower priority
than what you get with the common case where no global register vars are used,
or at most one or two.  The "weird" saving/restoring of %rdi into/from %r10 is
because the RA chose to use %rdi for a temporary used in incrementing of REG7
and loading the next pointer from it, while postreload managed to remove all
needs for such a temporary register, it is too late for the save/restore code
not to be emitted.


  parent reply	other threads:[~2011-03-04 11:23 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <bug-44281-4@http.gcc.gnu.org/bugzilla/>
2011-03-04  7:23 ` adam at consulting dot net.nz
2011-03-04  7:46 ` jakub at gcc dot gnu.org
2011-03-04 10:51 ` adam at consulting dot net.nz
2011-03-04 11:23 ` jakub at gcc dot gnu.org [this message]
2011-03-05  2:01 ` adam at consulting dot net.nz
2011-06-27 14:14 ` [Bug rtl-optimization/44281] [4.3/4.4/4.5/4.6/4.7 " rguenth at gcc dot gnu.org
2012-03-13 14:38 ` [Bug rtl-optimization/44281] [4.5/4.6/4.7/4.8 " jakub at gcc dot gnu.org
2012-07-02 11:09 ` rguenth at gcc dot gnu.org
2013-02-23 14:56 ` [Bug rtl-optimization/44281] [4.6/4.7/4.8 " steven at gcc dot gnu.org
2013-04-12 15:17 ` [Bug rtl-optimization/44281] [4.7/4.8/4.9 " jakub at gcc dot gnu.org
2014-06-12 13:46 ` [Bug rtl-optimization/44281] [4.7/4.8/4.9/4.10 " rguenth at gcc dot gnu.org
2014-12-19 13:44 ` [Bug rtl-optimization/44281] [4.8/4.9/5 " jakub at gcc dot gnu.org
2015-02-16 21:19 ` law at redhat dot com
2015-02-16 21:36 ` law at redhat dot com
2015-06-23  8:26 ` [Bug rtl-optimization/44281] [4.8/4.9/5/6 " rguenth at gcc dot gnu.org
2015-06-26 20:26 ` [Bug rtl-optimization/44281] [4.9/5/6 " jakub at gcc dot gnu.org
2015-06-26 20:37 ` jakub at gcc dot gnu.org
2010-05-26  5:12 [Bug regression/44281] New: Global Register variable pessimisation and regression adam at consulting dot net dot nz
2010-07-20 22:53 ` [Bug rtl-optimization/44281] [4.3/4.4/4.5/4.6 Regression] Global Register variable pessimisation steven at gcc dot gnu dot org
2010-07-20 22:55 ` pinskia at gcc dot gnu dot org
2010-07-22  8:48 ` rguenth at gcc dot gnu dot org
2010-09-11 11:16 ` adam at consulting dot net dot nz
2010-09-11 13:50 ` hjl dot tools at gmail dot com
2010-09-12 14:12 ` pinskia at gcc dot gnu dot org
2010-09-13  0:24 ` adam at consulting dot net dot nz

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