Long.bitCount micro-optimization

Maurizio Cimadamore maurizio.cimadamore at oracle.com
Tue May 9 14:28:20 UTC 2017

To expand a bit on Martin's point - I think your benchmark should 
include a 'baseline' version of bitCountInt/bitCountLong whose 
implementation simply delegates to the JDK methods 
(Integer.bitCount/Long.bitCount) - I see that bitCount is on the list of 
supported intrinsics [1], so, by adding those 'baselines' 
intrinsification should definitively kick in, and give you different 
(possibly even better) numbers.

[1] - 


On 09/05/17 03:54, Martin Buchholz wrote:
> I would also have benchmarked against the intrinsified version to see how
> it did.

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