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[Bug tree-optimization/30052] [4.2 Regression] points-to analysis slow and memory hungry
- From: "rguenther at suse dot de" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 11 Jun 2008 08:07:55 -0000
- Subject: [Bug tree-optimization/30052] [4.2 Regression] points-to analysis slow and memory hungry
- References: <bug-30052-7667@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #61 from rguenther at suse dot de 2008-06-11 08:07 -------
Subject: Re: [4.2 Regression] points-to analysis
slow and memory hungry
On Tue, 10 Jun 2008, giovannibajo at libero dot it wrote:
> ------- Comment #60 from giovannibajo at libero dot it 2008-06-10 17:26 -------
> If a knowledgable GCC developer could suggest *any* workaround at -O1 for this
> bug in 4.2 (including disabling whatever alias analysys causes the problem), it
> might be proposed as a fix within distros at least.
You can try if --param max-fields-for-field-sensitive=0 improves the
situation.
Other than that, try, in
tree-ssa-structalias.c:create_variable_info_for remove the
make_constraint_from_escaped and make_constraint_to_escaped calls for
the is_global cases. Note that you need to adjust find_what_p_points_to
to include escaped variables if escaped_id is set in the solution and
that call clobbering will need similar adjustments (and remember
escaped_id includes all globals implicitly). The problem with the
sipQt testcase is that it has 10000s of global vars it creates
constraints for, even though they are unused.
Richard.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30052