This is the mail archive of the
gcc-bugs@gcc.gnu.org
mailing list for the GCC project.
[Bug tree-optimization/26830] [4.1/4.2 Regression] Insane amount of compile-time / memory needed at -O1 and above
- From: "rguenth at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 23 Mar 2006 22:09:34 -0000
- Subject: [Bug tree-optimization/26830] [4.1/4.2 Regression] Insane amount of compile-time / memory needed at -O1 and above
- References: <bug-26830-10053@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #8 from rguenth at gcc dot gnu dot org 2006-03-23 22:09 -------
With structure aliasing on, we create 22326 SFTs for the
CShadingContext::execute function. Aliasing completely breaks down then:
execute: Total number of aliased vops: 18901314
execute: Total number of aliased vops after grouping: 4421064
Referenced variables in execute: 80934
This all results in lots of basic blocks with hundreds of PHI nodes with
hundreds of incoming edges in alias1. This is insane! Like
# SFT.14821_22241 = PHI <SFT.14821_41418(2), ... , SFT.14821_22241(9627)>;
(that line is 20000 characters long! Which makes roughly 1000 phi arguments!)
and there are 8800 such PHI_EXPRs for just one basic block!
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26830