Re: compile bug in HEAD?

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: Neil Conway <nconway(at)klamath(dot)dyndns(dot)org>
Cc: Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: compile bug in HEAD?
Date: 2002-04-18 01:41:07
Message-ID: 200204180141.g3I1f7Z15567@candle.pha.pa.us
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Neil Conway wrote:
> On Wed, Mar 27, 2002 at 07:56:15PM -0500, Peter Eisentraut wrote:
> > Neil Conway writes:
> >
> > > I'm curious; why is this "not the right fix"? According to the manpage:
> > >
> > > -l turns on maximum compatibility with the original
> > > AT&T lex implementation. Note that this does not
> > > mean full compatibility. Use of this option
> > > costs a considerable amount of performance...
> >
> > The manpage also lists the specific incompatibilities. I think we should
> > not be affected by them, but someone better check before removing the -l.
>
> AFAICT current sources don't actually use "-l" anywhere.
>
> However, it does appear that we can tweak flex for more performance
> (usually at the expense of a larger generated parser). In particular, it
> looks like we could use "-Cf" or "-CF". Is this a good idea?
>
> While we're on the subject of minor optimizations, is there a reason why
> we execute gcc with "-O2" rather than "-O3" during compilation?

Added to TODO:

* Try flex flags -Cf and -CF to see if performance improves

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Bruce Momjian | http://candle.pha.pa.us
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