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Re: Compilation performance comparison of GCC 3.4.2 and GCC 4.0.0 (041024) on MICO sources
- From: Richard Guenther <richard dot guenther at gmail dot com>
- To: Steven Bosscher <stevenb at suse dot de>
- Cc: Karel Gardas <kgardas at objectsecurity dot com>, GCC Mailing List <gcc at gcc dot gnu dot org>
- Date: Mon, 25 Oct 2004 16:47:04 +0200
- Subject: Re: Compilation performance comparison of GCC 3.4.2 and GCC 4.0.0 (041024) on MICO sources
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- Reply-to: Richard Guenther <richard dot guenther at gmail dot com>
On Mon, 25 Oct 2004 16:35:58 +0200, Steven Bosscher <stevenb@suse.de> wrote:
> On Monday 25 October 2004 14:01, Karel Gardas wrote:
> > As a first possible step, I would like to propose solving ir.cc
> > regressions, since if you do it, even -O1/-O2 compilation will be faster
> > in comparison with 3.4.2 (ir.cc is 580kB long generated file)
>
> With the attached patchlet to overcome the problem that we basically
> assign tons of unrelated stuff to TV_EXPAND, I see this:
>
> tree find referenced vars: 15.39 (13%) usr 0.06 ( 2%) sys 15.89 (13%) wall
>
> That seems too expensive for what the pass does. Top of the oprofile:
>
> 902280 10.4203 21489 8.9873 cc1plus cc1plus ggc_alloc_stat
> 700233 8.0869 23820 9.9622 cc1plus cc1plus cgraph_reset_static_var_maps
Maybe even using walk_tree_without_duplicates will help. I can't see
why we don't do this.
Also we walk the tree recursively(!) in add_referenced_var through
find_vars_r. But this
is just from a quick look.
Richard.