[PATCH] improve string find algorithm

[Jonathan Wakely]

On 10/01/17 17:12 +0100, Manfred wrote:
>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 
>__first in principle is not. Would it be worth testing the performance 
>with traits_type::compare running from 1-after __s and __first?

Yes, it's probably worth checking. I assume Aditya or Sebastian did
verify that, because there's a comment in their libc++ patch about it,
but we might get diffeernt results with GCC, or with GNU libc.