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Re: Scheduler and GCC CFG
- From: David Edelsohn <dje at watson dot ibm dot com>
- To: Jan Hubicka <jh at suse dot cz>
- Cc: gcc at gcc dot gnu dot org
- Date: Sat, 21 Dec 2002 13:39:40 -0500
- Subject: Re: Scheduler and GCC CFG
>>>>> Jan Hubicka writes:
Jan> ... it already should be
Jan> enough to test whether superblock scheduling can bring us something over
Jan> region based scheduler we have right now. I tried that on Athlon and
Jan> the results are mostly random. This is partly due to exact CPU model
Jan> (that has improved by DFA now), abd the fact that Athlon is not very
Jan> sensitive to scheduling.
On the cfg-branch, you run EBB scheduler instead of the
post-reload region scheduler. The tracer pass is run before the first
scheduling pass, so why not run EBB scheduler instead of first scheduling
pass? Is this because first scheduling pass is disabled for x86? I would
expect the first scheduling pass to have much more freedom to move
instructions within the superblocks.
David