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Re: [PATCH] improve string find algorithm

From: Manfred <mx2927 at gmail dot com>
To: libstdc++ at gcc dot gnu dot org
Date: Tue, 10 Jan 2017 17:12:05 +0100
Subject: Re: [PATCH] improve string find algorithm
Authentication-results: sourceware.org; auth=none
References: <1481132816-31162-1-git-send-email-aditya.k7@samsung.com> <CGME20170106133507epcas2p15eaabe5ca279349c9f3603a6c2bb61d8@epcas2p1.samsung.com> <20170106133502.GB2966@redhat.com> <016101d2682b$136dc890$3a4959b0$@samsung.com> <20170106202058.GH2966@redhat.com>

On 1/6/2017 9:20 PM, Jonathan Wakely wrote:

+	  // Compare the full strings from the first occurrence of __elem0.
+	  // We already know that __first[0] == __s[0] but compare them again
+	  // anyway because __s is probably aligned, which helps memcmp.
+	  if (traits_type::compare(__first, __s, __n) == 0)
+	    return __first - __data;

I am not sure if __s being aligned really helps here, given that __firstin principle is not. Would it be worth testing the performance withtraits_type::compare running from 1-after __s and __first?

Follow-Ups:
- Re: [PATCH] improve string find algorithm
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References:
- Re: [PATCH] improve string find algorithm
  - From: Jonathan Wakely
- RE: [PATCH] improve string find algorithm
  - From: Aditya Kumar
- Re: [PATCH] improve string find algorithm
  - From: Jonathan Wakely

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