This is the mail archive of the
gcc@gcc.gnu.org
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: Diego Novillo <dnovillo at redhat dot com>
- To: Karel Gardas <kgardas at objectsecurity dot com>
- Cc: "gcc at gcc dot gnu dot org" <gcc at gcc dot gnu dot org>
- Date: Tue, 04 May 2004 18:10:10 -0400
- Subject: Re: Compilation performance comparison of 3.5.0 and TreeSSA treeson MICO sources as requested in: [tree-ssa] Merge status 2004-05-03
- Organization: Red Hat Canada
- References: <Pine.LNX.4.43.0405042239400.13381-100000@thinkpad.gardas.net>
On Tue, 2004-05-04 at 16:50, Karel Gardas wrote:
> Conclusion: compile time regressions for both -O0 and -O2 compilation.
>
Thanks. -O0 is a known loser right now. The gimplification process
tends to create extremely bloated RTL. That can only be fixed by
introducing simplistic tree optimization passes at O0. I see this as a
post-merge exercise, as well.
As far as the -O2 regressions, do you have the -ftime-report output?
IMO, these C++ problems are better addressed once tree-ssa is in
mainline. If it's similar to the other C++ applications showing compile
time regressions, this will need work in a bunch of places inside GCC
(memory allocator, parser, trees, etc).
Diego.