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Re: c/7344: performance regression on huge case statements
- From: Daniel Berlin <dberlin at dberlin dot org>
- To: Nathanael Nerode <neroden at twcny dot rr dot com>
- Cc: gcc-gnats at gcc dot gnu dot org, rschiele at uni-mannheim dot de,gcc-bugs at gcc dot gnu dot org, nobody at gcc dot gnu dot org, jh at suse dot cz
- Date: Thu, 10 Oct 2002 22:08:47 -0400
- Subject: Re: c/7344: performance regression on huge case statements
On Thursday, October 10, 2002, at 10:04 PM, Nathanael Nerode wrote:
http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-
trail&database=gcc&pr=7344
I'm tired of investigating this, but it seems likely that the problem
was introduced with the introduction of et-forest.c, since that's
where the loop is. This was introduced by Pavel Nejedly and committed
to mainline by Jan Hubicka (along with most of the surrounding code).
(So that's why I'm ccing you; it looks like you caused it, so maybe
you can figure out how to fix it. :-/)
As I mentioned, this is likely a known problem, with a known fix.
Jan, if you don't have plans to make it constant time soon, i suggest
we cache the info using the patch that is on the tree-ssa branch.
--Nathanael