This is the mail archive of the
mailing list for the GCC project.
Re: Compilation performance comparison of 3.5.0 and TreeSSA treeson MICO sources as requested in: [tree-ssa] Merge status 2004-05-03
- From: Karel Gardas <kgardas at objectsecurity dot com>
- To: Daniel Berlin <dberlin at dberlin dot org>
- Cc: Diego Novillo <dnovillo at redhat dot com>, "gcc at gcc dot gnu dot org" <gcc at gcc dot gnu dot org>, Steven Bosscher <stevenb at suse dot de>, <law at redhat dot com>
- Date: Wed, 5 May 2004 22:12:20 +0200 (CEST)
- Subject: Re: Compilation performance comparison of 3.5.0 and TreeSSA treeson MICO sources as requested in: [tree-ssa] Merge status 2004-05-03
On Wed, 5 May 2004, Daniel Berlin wrote:
> Note that in almost all of his cases, the parser takes at least 15%,
> and usually 30%+ of the time of compilation.
Yes, that's true. Parser and name lookup are most expensive tasks. But how
is it possible that trunk is so much (~20%) faster than tree-ssa, when
tree-ssa is based on trunk?
> Note that the parser times are significantly slower with tree-ssa than
> they are for mainline (be it because of memory locality, bad time
> accounting, or whatever)
Yes, but why?
> I only mention this because i'm pretty sure that right now, even if we
> made gimplification take no time on these testcases, we'd still have a
> large percent regression just from the parser times.
Agree, but maybe it just tell something about not so good optimizations on
tree-ssa branch in comparison with trunk, i.e. trunk optimizes C++ parser
much better... Is it possible to not bootstrap tree-ssa, but just compile
it by GCC3.4.0/3.5.0 and see if parser is faster? If so, how?
Karel Gardas firstname.lastname@example.org
ObjectSecurity Ltd. http://www.objectsecurity.com