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Fri Oct 7 21:46:15 CEST 2011 · https://mail.python.org/pipermail/python-dev/2011-October/113961.html

Le jeudi 6 octobre 2011 02:06:30, Victor Stinner a écrit :
> The rfind case is really strange: the code between Python 3.2 and 3.3 is
> exactly the same. Even in Python 3.2: rfind looks twice faster than find:
> 
> ("AB"*300+"C").find("BC") (*1000) : 1.21
> ("C"+"AB"*300).rfind("CA") (*1000) : 0.57

It looks to be a gcc bug: using attached patch (written by Antoine), str.find() 
is a little bit faster. With the patch, the function does the same memory 
access, but it generates a different machine code.

I don't know exactly the difference yet, but it may be related to the CMOVNE 
instruction (which looks to be slower than a classical conditional jump, JNE).

Victor
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[Python-Dev] New stringbench benchmark results