RFR 8170159 Improve the performance of BitSet traversal

[Paul Sandoz]

Thanks! Doh, obvious in hindsight.

> On Jun 15, 2018, at 11:05 AM, Martin Buchholz <martinrb at google.com> wrote:
> 
> It took me a while to realize why you were checking tz < 63.  It's because the shift by 64 that might occur below would be a no-op!

Right!

> 1301                             action.accept(i++);
> 1302                             word &= (WORD_MASK << i);
> Can we rewrite to simply flip the one bit via
> 
> word &= ~(1L << i);
> action.accept(i++);
> 
> and then we can simplify the tz handling?
> 


Yes, and there is no need to increment i:

  http://cr.openjdk.java.net/~psandoz/jdk/JDK-8170159-bitset-traverse/webrev/src/java.base/share/classes/java/util/BitSet.java.sdiff.html <http://cr.openjdk.java.net/~psandoz/jdk/JDK-8170159-bitset-traverse/webrev/src/java.base/share/classes/java/util/BitSet.java.sdiff.html>

Paul.