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From: "meissner at linux dot vnet.ibm.com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/50101] GCC 4.5 and 4.6 generate suboptimal code on ppc for countdown loops when the CTR register cannot be used
Date: Fri, 19 Aug 2011 14:12:00 -0000 [thread overview]
Message-ID: <bug-50101-4-z3fe47tnGI@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-50101-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50101
--- Comment #8 from Michael Meissner <meissner at linux dot vnet.ibm.com> 2011-08-19 14:05:51 UTC ---
On Thu, Aug 18, 2011 at 08:58:28AM +0000, rguenth at gcc dot gnu.org wrote:
> Did you try pessimizing the non-ctr reg alternatives (and the memory
> alternative even more)? Like adding ! to the non-ctr alternatives
> and ? to the memory one? Not sure if those markers are looked at
> by IRA though.
Yes, I should have mentioned that I tried various combinations of ?, !, and *
and the combinations I tried aborted. I've certainly suspected that IRA now
longer looks at !, ?, and * like the previous register allocator did
previously. It may be that it is special due to being a JUMP_INSN.
next prev parent reply other threads:[~2011-08-19 14:07 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-16 20:57 [Bug rtl-optimization/50101] New: " meissner at gcc dot gnu.org
2011-08-16 21:22 ` [Bug rtl-optimization/50101] " meissner at gcc dot gnu.org
2011-08-17 8:13 ` rguenth at gcc dot gnu.org
2011-08-17 15:46 ` meissner at gcc dot gnu.org
2011-08-17 15:47 ` meissner at gcc dot gnu.org
2011-08-17 15:48 ` meissner at gcc dot gnu.org
2011-08-17 16:32 ` meissner at gcc dot gnu.org
2011-08-18 9:01 ` rguenth at gcc dot gnu.org
2011-08-19 14:12 ` meissner at linux dot vnet.ibm.com [this message]
2011-08-19 15:54 ` law at redhat dot com
2011-12-15 20:53 ` [Bug rtl-optimization/50101] [4.5/4.6 regression] " pinskia at gcc dot gnu.org
2012-07-02 12:03 ` rguenth at gcc dot gnu.org
2013-04-12 16:18 ` [Bug rtl-optimization/50101] [4.6 " jakub at gcc dot gnu.org
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