This is the mail archive of the
gcc-bugs@gcc.gnu.org
mailing list for the GCC project.
[Bug lto/44334] rnflow.f90 ~27% slower with -fwhole-program -flto after revision 159852
- From: "jh at suse dot de" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Tue, 25 Jan 2011 17:57:59 +0000
- Subject: [Bug lto/44334] rnflow.f90 ~27% slower with -fwhole-program -flto after revision 159852
- Auto-submitted: auto-generated
- References: <bug-44334-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44334
--- Comment #46 from jh at suse dot de 2011-01-25 17:57:38 UTC ---
I sorted out increasing large function growth ratio as most safe way
to deal with (easier half of) this problem. Unlike the parameters for
inline limits it won't cause code size issues. It just allow somewhat
bigger functions and thus stress more the backend on its linearity.
Given that the parameter was never tuned since its inclusion in GCC
4.2, I guess we are not terribly sensitive here. We also improved a
bit in the scalability here as I tuned the df code bit for LTO and
spagetti code.
Otherwise we need to wait for 4.7 or possibly 4.6.1. That is fine with me.
I will still run tests tonight on how increasing the parameter affect
our tester. This is first time I see it hit in perfomrance sensitive
way. Not sure how common it is in practice since I never really tried
to change it.