From: Junio C Hamano <gitster@pobox.com>
Date: Sat, 10 Jan 2009 20:37:09 GMT
Subject: Re: [PATCH 2/2] grep: don't call regexec() for fixed strings
Message-ID: <7vbpuex5hm.fsf@gitster.siamese.dyndns.org>
In-Reply-To: <4967DB4A.2000702@lsrfire.ath.cx>

René Scharfe <rene.scharfe@lsrfire.ath.cx> writes:

> Add the new flag "fixed" to struct grep_pat and set it if the pattern
> is doesn't contain any regex control characters in addition to if the
> flag -F/--fixed-strings was specified.
>
> This gives a nice speed up on msysgit, where regexec() seems to be
> extra slow.  Before (best of five runs):

Thanks, and...

>  static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)
>  {
> -	int err = regcomp(&p->regexp, p->pattern, opt->regflags);
> +	int err;
> +
> +	if (opt->fixed || is_fixed(p->pattern))
> +		p->fixed = 1;
> +	if (opt->regflags & REG_ICASE)
> +		p->fixed = 0;

... thanks again for being extra careful.  That's why I *love* your
patches.