This is the mail archive of the
gcc-bugs@gcc.gnu.org
mailing list for the GCC project.
[Bug tree-optimization/32921] [4.3/4.4 Regression] Revision 126326 causes 12% slowdown
- From: "dnovillo at google dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 2 May 2008 12:32:22 -0000
- Subject: [Bug tree-optimization/32921] [4.3/4.4 Regression] Revision 126326 causes 12% slowdown
- References: <bug-32921-682@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #50 from dnovillo at google dot com 2008-05-02 12:32 -------
Subject: Re: [4.3/4.4 Regression] Revision
126326 causes 12% slowdown
On 05/02/08 08:16, rguenth at gcc dot gnu dot org wrote:
> and dropping the final dom pass in favor of another FRE one (DOM has
> weaker memory optimization but in addition does some jump threading and
> cond expr combining, both of which don't happen a lot after loop
> optimizations).
Along these lines, I think we would really benefit from doing a thorough
study of pass reordering using the techniques in GCC-ICI (GCC Summit
2008) and COLE (CGO 2008). Both have found significant improvements
with different optimization pipelines.
> Note that teaching DOM about the alias-oracle is very difficult and
> unlikely to happen - I'd rather get rid of DOM completely.
Agreed.
Diego.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32921