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From: Serhiy Storchaka <storchaka@gmail.com>
Subject: Re: Challenge: optimizing isqrt
Date: Wed, 26 Nov 2014 18:24:59 +0200
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On 26.11.14 02:46, Dave Angel wrote:
> Unfortunately, for many values, the version of the function with >>1 is
> slower.  It's only when the argument is bigger than 10**40 that it's as
> much as 1% faster.  But it's true that for really large values, it's
> quicker.

Note that this path is used only for values above 2**53 (about 10**16). 
For all tested values from 10**16 to 10**40 the difference between two 
versions is not larger than 1% (in one or other direction). But the 
difference between different runs of the benchmark for the same version 
vary about 1%. So the difference between versions in this range doesn't 
matter.