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Re: More backref performance - no strncmp
- From: Daniel Jacobowitz <drow at mvista dot com>
- To: Bonzini <bonzini at gnu dot org>
- Cc: libc-alpha at sources dot redhat dot com
- Date: Wed, 23 Oct 2002 11:26:59 -0400
- Subject: Re: More backref performance - no strncmp
- References: <006a01c27a79$dd47fff0$b71a1897@bonz>
On Wed, Oct 23, 2002 at 11:44:34AM +0200, Bonzini wrote:
> I think that using strncmp to match backreferences is incorrect because it
> fails when matching nuls, not to mention inefficient. Also, the return
> value of memcmp and strncmp is quite `complicated' to compute while we only
> need a yes/no answer. For this reason the attached patch replaces strncmp
> with a customized memcmp. Performance improvement is on the order of 5%
> (2.1 s before, 1.98s after on factor.sed).
> 2002-10-23 Paolo Bonzini (email@example.com)
> * posix/regexec.c (my_memcmp): new function.
> Used instead of strncmp throughout the file.
I don't think this is a good idea... memcmp is a very highly optimized
function in the system library already; why not use it?
MontaVista Software Debian GNU/Linux Developer