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Re: Should -fcross-jumping be part of -O1?
- From: Scott Robert Ladd <coyote at coyotegulch dot com>
- To: unlisted-recipients:; (no To-header on input)
- Cc: gcc mailing list <gcc at gcc dot gnu dot org>
- Date: Tue, 02 Dec 2003 17:17:49 -0500
- Subject: Re: Should -fcross-jumping be part of -O1?
- References: <20031202153955.6E36B1587F1@kanga.canids>
I'm working out a plan of action in terms of finding better option sets
for the various -O levels. The comments in this thread have been most
useful.
1) I can analyze for executable code size, compile speed, and execution
time; I'm adding such options to Acovea.
2) Testing only on Intel chips is a severe limitation; I'm updating
Acovea for my UltraSparc IIi system, and I have a G4 Mac coming
available in the next week or so. In the next few days, I'll publish an
update to Acovea, so people with Alphas and such can test on their
boxes, if they want to.
3) In addition to the other categories, I'm also going to look at a
-Oaccuracy option. As it stands now, options that may cause inaccuracies
are bundled inside -ffast-math; I've seen some evidence of accuracy
problems with other options as well, but want to confirm my anecdotal
evidence with some real tests.
4) Is it reasonable to perform different optimizations on different
architectures? It seems to me that a PowerPC or Opteron has very
different characteristics from a P4, but maybe I'm splitting hairs.
--
Scott Robert Ladd
Coyote Gulch Productions (http://www.coyotegulch.com)
Software Invention for High-Performance Computing