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From: "dalej at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/19398] secondary reloads don't consider "m" alternatives
Date: Mon, 01 Aug 2005 18:46:00 -0000	[thread overview]
Message-ID: <20050801184645.10639.qmail@sourceware.org> (raw)
In-Reply-To: <20050112133406.19398.uros@kss-loka.si>


------- Additional Comments From dalej at gcc dot gnu dot org  2005-08-01 18:46 -------
This is very close to the problem I ran into reported here:
http://gcc.gnu.org/ml/gcc/2005-07/msg01084.html
That one is fixed by the combination of the patch in PR 19653 and the patch here:
http://gcc.gnu.org/ml/gcc/2005-07/msg01123.html
However that is insufficient to fix this case.  The difficulty is that regmove causes the same pseudo to 
be used for the operands and the result of the multiply.  Consider that reg as all one, ST(0) is the best 
place for it, and you get the extra move.  If you turn off regmove, the patches above fix this problem.
Maybe we should do that?  It seems like the register allocator should be doing what regmove is trying 
to do.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19398


  parent reply	other threads:[~2005-08-01 18:46 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-01-12 13:34 [Bug target/19398] New: Non-optimal code with cvttss2si uros at kss-loka dot si
2005-01-12 15:56 ` [Bug target/19398] " pinskia at gcc dot gnu dot org
2005-01-14 23:21 ` pinskia at gcc dot gnu dot org
2005-01-18 11:20 ` [Bug rtl-optimization/19398] secondary reloads don't consider "m" alternatives rth at gcc dot gnu dot org
2005-01-18 12:22 ` uros at kss-loka dot si
2005-03-15 10:10 ` giovannibajo at libero dot it
2005-03-15 11:44 ` bernds_cb1 at t-online dot de
2005-03-15 12:23 ` giovannibajo at libero dot it
2005-03-15 12:35 ` uros at kss-loka dot si
2005-08-01 18:46 ` dalej at gcc dot gnu dot org [this message]
2005-08-08  9:58 ` bonzini at gcc dot gnu dot org
2005-08-08 10:17 ` bonzini at gcc dot gnu dot org
     [not found] <bug-19398-1649@http.gcc.gnu.org/bugzilla/>
2006-10-21 19:27 ` uros at gcc dot gnu dot org
     [not found] <bug-19398-4@http.gcc.gnu.org/bugzilla/>
2012-10-27  8:14 ` ubizjak at gmail dot com
2012-11-13 18:34 ` ubizjak at gmail dot com
2012-11-20 18:03 ` uros at gcc dot gnu.org
2012-11-20 18:30 ` ubizjak at gmail dot com

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