Re: compile bug in HEAD? - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: compile bug in HEAD?
Date
Msg-id 200204180141.g3I1f7Z15567@candle.pha.pa.us
Whole thread Raw
In response to Re: compile bug in HEAD?  (nconway@klamath.dyndns.org (Neil Conway))
List pgsql-hackers
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

--  Bruce Momjian                        |  http://candle.pha.pa.us pgman@candle.pha.pa.us               |  (610)
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