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From: "ubizjak at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/54716] Select best typed instruction for bitwise operations
Date: Wed, 26 Sep 2012 20:59:00 -0000	[thread overview]
Message-ID: <bug-54716-4-pcW3n5X5dN@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-54716-4@http.gcc.gnu.org/bugzilla/>


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54716

--- Comment #9 from Uros Bizjak <ubizjak at gmail dot com> 2012-09-26 20:59:24 UTC ---
(In reply to comment #8)
> (In reply to comment #7)
> > I haven't noticed a measurable performance difference though on Intel SNB 2600
> > CPU though, so perhaps the patch isn't needed.
> 
> Ah, I assumed they had a good reason for creating so many variants of the same
> instruction. If there is no difference (or even a difference in the wrong
> direction because of the instruction size), feel free to close the bug.

I think we should still go with the proposed patch. Insn size is handled by
choosing *PS mode attribute for -Os in the insn pattern, and there is no size
difference for AVX. If some target prefers *PS variants, there is always
X86_TUNE_SSE_PACKED_SINGLE_INSN_OPTIMAL flag available.

But please put the code into a helper function. Due to VI mode iterator, the
code is emitted eight times!


  parent reply	other threads:[~2012-09-26 20:59 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-09-26 12:37 [Bug target/54716] New: " glisse at gcc dot gnu.org
2012-09-26 13:44 ` [Bug target/54716] " jakub at gcc dot gnu.org
2012-09-26 13:46 ` jakub at gcc dot gnu.org
2012-09-26 13:56 ` ubizjak at gmail dot com
2012-09-26 14:01 ` ubizjak at gmail dot com
2012-09-26 14:20 ` ubizjak at gmail dot com
2012-09-26 14:23 ` jakub at gcc dot gnu.org
2012-09-26 14:57 ` jakub at gcc dot gnu.org
2012-09-26 15:41 ` jakub at gcc dot gnu.org
2012-09-26 15:53 ` glisse at gcc dot gnu.org
2012-09-26 20:59 ` ubizjak at gmail dot com [this message]
2012-09-28 12:21 ` jakub at gcc dot gnu.org
2012-11-10 12:55 ` glisse at gcc dot gnu.org

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