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From: "carlr at freemail dot gr" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/42621] [4.4 Regression] Computed gotos on AMD 800% slower
Date: Mon, 18 Jan 2010 13:14:00 -0000 [thread overview]
Message-ID: <20100118131435.5266.qmail@sourceware.org> (raw)
In-Reply-To: <bug-42621-18630@http.gcc.gnu.org/bugzilla/>
------- Comment #10 from carlr at freemail dot gr 2010-01-18 13:14 -------
Please note that computed gotos are factored out because "they are a hell to
deal with" in tree-cfg.c:build_gimple_cfg(). This means that they MUST be
unfactored out as promised in the comment without leaving this to another
optimization step that may or may not be enabled.
Also, for our product there are 97 "extra jumps" and 95 of them are long jumps,
i.e:
12be0: ff e1 jmp *%ecx
...
12dda: e9 01 fe ff ff jmp 12be0 <main_loop+0x220>
...
so this is a serious both speed and size pessimisation :(
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42621
next prev parent reply other threads:[~2010-01-18 13:14 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-05 11:44 [Bug c/42621] New: 4.4/4.5 Regression, " fredrik dot svahn at gmail dot com
2010-01-05 12:46 ` [Bug rtl-optimization/42621] [4.4/4.5 Regression] " rguenth at gcc dot gnu dot org
2010-01-05 12:50 ` steven at gcc dot gnu dot org
2010-01-05 21:51 ` steven at gcc dot gnu dot org
2010-01-05 21:56 ` pinskia at gcc dot gnu dot org
2010-01-05 22:11 ` steven at gcc dot gnu dot org
2010-01-06 11:37 ` fredrik dot svahn at gmail dot com
2010-01-06 11:44 ` fredrik dot svahn at gmail dot com
2010-01-06 23:00 ` fredrik dot svahn at gmail dot com
2010-01-07 14:51 ` rguenth at gcc dot gnu dot org
2010-01-10 23:31 ` steven at gcc dot gnu dot org
2010-01-13 22:27 ` [Bug rtl-optimization/42621] [4.4 " rguenth at gcc dot gnu dot org
2010-01-18 13:14 ` carlr at freemail dot gr [this message]
2010-01-21 13:16 ` jakub at gcc dot gnu dot org
2010-04-30 9:25 ` jakub at gcc dot gnu dot org
2010-07-14 20:49 ` jyasskin at gmail dot com
[not found] <bug-42621-4@http.gcc.gnu.org/bugzilla/>
2010-10-01 12:12 ` jakub at gcc dot gnu.org
2011-04-16 11:16 ` jakub at gcc dot gnu.org
2011-06-10 8:51 ` jaak at ristioja dot ee
2011-06-10 8:53 ` jaak at ristioja dot ee
2012-03-13 16:39 ` jakub at gcc dot gnu.org
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