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Re: [Patch] Change default executor to DFS in regex

From: Tim Shen <timshen91 at gmail dot com>
To: "libstdc++" <libstdc++ at gcc dot gnu dot org>, gcc-patches <gcc-patches at gcc dot gnu dot org>
Date: Fri, 18 Oct 2013 23:53:48 -0400
Subject: Re: [Patch] Change default executor to DFS in regex
Authentication-results: sourceware.org; auth=none
References: <CAPrifD=xODhzMevpww0BnkQh1Ju2btXxd-fFde=fN7nKzWmgBQ at mail dot gmail dot com>

On Fri, Oct 18, 2013 at 9:13 PM, Tim Shen <timshen91@gmail.com> wrote:
> As the comment in this patch said, DFS approach is faster in simple
> regex, but exponentially slower in complex(many quantifier) cases.

Actually I suggest to use DFS where number of quantifiers < 2, to make
this 'optimization' more conservative. Now `split regex`, say "\s+"
can be optimized.

-- 
Tim Shen

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Follow-Ups:
- Re: [Patch] Change default executor to DFS in regex
  - From: Paolo Carlini

References:
- [Patch] Change default executor to DFS in regex
  - From: Tim Shen

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