Vectorized BitSet operations

[Jerven Bolleman]

Hi All,

My apologies in advance if I am a rather clueless.

I am interested in seeing the use of SSE/AVX instructions use for some
methods in java.util.Bitset. e.g. the "or" and "and" methods.

For example I believe that this loop
<http://grepcode.com/file/repository.grepcode.com/java/root/jdk/openjdk/6-b14/java/util/BitSet.java#681>
can be vectorized.

My first thought was that an intrinsic/MethodSubstitution would be a good
start.
However, it would be even nicer if this type of code can be auto vectorized.
I was wondering if anyone has worked on this or if this is already the case?

Because working auto vectorization could accelerate this loop
<http://grepcode.com/file/repo1.maven.org/maven2/org.apache.lucene/lucene-core/3.0.1/org/apache/lucene/util/OpenBitSet.java#661>
used in Lucene
a lot. While the intrinsic has a smaller use case.

In my specific case a bitset of 20mb or larger is not uncommon. So in these
cases doing more work per tick is interesting.

If I wanted to have a go at implementing the intrinsic are there any
pitfalls I need to be aware of?

Regards,
Jerven









-- 
Jerven Bolleman
me at jerven.eu