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Re: compile time regression
- From: Paolo Bonzini <paolo dot bonzini at lu dot unisi dot ch>
- To: Diego Novillo <dnovillo at redhat dot com>
- Cc: gcc at gcc dot gnu dot org, Richard Guenther <rguenther at suse dot de>
- Date: Tue, 22 Aug 2006 21:00:08 +0200
- Subject: Re: compile time regression
- References: <email@example.com> <44EB4EAF.firstname.lastname@example.org>
Diego Novillo wrote:
Benjamin Kosnik wrote on 08/22/06 07:56:
Hey y'all. I'm just getting back from vacation and as I re-build my
testing baselines, I've noticed a huge compilation time regression.
This happened sometime post Aug 1, 2006. Anybody else notice?
Yes, something did happen after Aug11. The SPEC testers show a 2-3%
bootstrap time increase from Aug11 to Aug13.
I don't see anything but this:
2006-08-11 Richard Guenther <email@example.com>
* simplify-rtx.c (simplify_const_relational_operation):
Simplify A CMP B to A - B CMP 0 only for EQ and NE comparison
but a 2-3% increase seems a lot! If it was this patch, it should be
possible to find the place in GCC (or libiberty or libcpp) that is being
I'm starting a bootstrap timing comparison to find if this is a red
herring. I'll get the results next morning.