From: Ian Lance Taylor <iant@google.com>
To: Steven Bosscher <stevenb.gcc@gmail.com>
Cc: Vladimir Makarov <vmakarov@redhat.com>,
GCC Mailing List <gcc@gcc.gnu.org>
Subject: Re: Where does the time go?
Date: Thu, 20 May 2010 21:09:00 -0000 [thread overview]
Message-ID: <mcr632i1drm.fsf@dhcp-172-17-9-151.mtv.corp.google.com> (raw)
In-Reply-To: <AANLkTimQnnAiNuIevpRmmOfeZzj1S-TCVLeQLfgnnEtw@mail.gmail.com> (Steven Bosscher's message of "Thu\, 20 May 2010 22\:36\:23 +0200")
Steven Bosscher <stevenb.gcc@gmail.com> writes:
> And finally: expand. This should be just a change of IR format, from
> GIMPLE to RTL. I have no idea why this pass always shows up in the top
> 10 of slowest parts of GCC. Lowering passes on e.g. WHIRL, or GENERIC
> lowering to GIMPLE, never show up in the compile time overviews.
expand unfortunately does more than just convert IR. It also does
things like changing division by a constant into multiplication by a
constant, and changing multiplication by a constant into a set of
shifts and adds. It does various optimizations involving store flags
(a = b == c;). When expanding function calls, it generates
instructions to put arguments in the right place in registers and on
the stack. Etc.
Ian
next prev parent reply other threads:[~2010-05-20 21:09 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-20 15:55 Steven Bosscher
2010-05-20 19:16 ` Vladimir Makarov
2010-05-20 19:57 ` Toon Moene
2010-05-20 20:36 ` Steven Bosscher
2010-05-20 20:54 ` Duncan Sands
2010-05-20 21:14 ` Steven Bosscher
2010-05-23 19:09 ` Joseph S. Myers
2010-05-24 17:00 ` Mark Mitchell
2010-05-24 21:07 ` Steven Bosscher
2010-05-24 23:22 ` Mark Mitchell
2010-05-25 1:20 ` Joseph S. Myers
2010-05-20 21:09 ` Ian Lance Taylor [this message]
2010-05-20 21:14 ` Xinliang David Li
2010-05-20 21:18 ` Steven Bosscher
2010-05-20 21:21 ` Xinliang David Li
2010-05-21 10:54 ` Richard Guenther
2010-05-21 13:26 ` Jan Hubicka
2010-05-21 15:06 ` Richard Guenther
2010-05-21 15:49 ` Jan Hubicka
2010-05-21 17:06 ` Xinliang David Li
2010-05-21 17:07 ` Richard Guenther
2010-05-20 19:36 ` Joseph S. Myers
2010-05-20 20:35 ` Eric Botcazou
2010-05-20 20:42 ` Eric Botcazou
2010-05-21 20:43 ` Diego Novillo
2010-05-20 21:28 Bradley Lucier
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