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Re: gcc 3.1 is still very slow, compared to 2.95.3
- From: Zack Weinberg <zack at codesourcery dot com>
- To: Marc Espie <espie at nerim dot net>
- Cc: gcc at gcc dot gnu dot org
- Date: Fri, 17 May 2002 09:02:41 -0700
- Subject: Re: gcc 3.1 is still very slow, compared to 2.95.3
- References: <20020517144258.A17881@tetto.liafa.jussieu.fr>
On Fri, May 17, 2002 at 02:42:58PM +0200, Marc Espie wrote:
> Okay, now, what passes is gcc 3.1 running that slow it down that much ?
> What would be the equivalent set of options to gcc's 2.95.3 -O2, so that
> I can see whether we can get down to more reasonable numbers ?
I don't think it's practical to determine that list. Too many things
are conditional only on if (optimize) or if (optimize > 1)...
Your best bet is probably to add -Q to CFLAGS, record all the output,
and write a script to mangle it into a coherent report.
Also, could you try comparisons at -O1? Fewer optimization passes
have been added to that level.