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Re: Bootstrap times on mainline are getting worse
- From: David Edelsohn <dje at watson dot ibm dot com>
- To: Diego Novillo <dnovillo at redhat dot com>
- Cc: "Kaveh R. Ghazi" <ghazi at caip dot rutgers dot edu>, gcc at gcc dot gnu dot org, ritzert at t-online dot de, schwab at suse dot de
- Date: Fri, 18 Oct 2002 12:36:31 -0400
- Subject: Re: Bootstrap times on mainline are getting worse
>>>>> Diego Novillo writes:
Diego> +2002-10-04 David Edelsohn <edelsohn@gnu.org>
Diego> +
Diego> + * unroll.c (copy_loop_body): Remove REG_EQUAL note attached to
Diego> + copied instruction if the note is not loop invariant.
Diego> +
Diego> But neither should have had any effects on SPECint. Anyway, I'll
Diego> start undoing patches as time permits.
My patch only should have an effect when unrolling is enabled,
which it is not by default when bootstrapping. I am worried about the
performance impact with -funroll-loops, but I checked the SPEC runs and
did not see a dramatic change.
Also, this slow-down could be due to the increasing complexity of
the x86 port, not a generic slow-down in the common parts of the
compiler. More complete cost models and register classes increase the
complexity of the port and the time spent in various
architecture-dependent compiler phases.
David