[
https://issues.apache.org/jira/browse/LUCENE-5856?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14080617#comment-14080617
]
Uwe Schindler commented on LUCENE-5856:
---------------------------------------
Thanks, cool! Reading the JVM spec is sometimes useful. It is interesting why
Hotspot oitsself does not remove the & in our code during optimization.
> remove useless & 0x3f from *BitSet.get and company
> --------------------------------------------------
>
> Key: LUCENE-5856
> URL: https://issues.apache.org/jira/browse/LUCENE-5856
> Project: Lucene - Core
> Issue Type: Improvement
> Reporter: Robert Muir
> Fix For: 5.0, 4.10
>
> Attachments: LUCENE-5856.patch
>
>
> java specification says:
> {quote}
> If the promoted type of the left-hand operand is long, then only the six
> lowest-order bits of the right-hand operand are used as the shift distance.
> It is as if the right-hand operand were subjected to a bitwise logical AND
> operator & (ยง15.22.1) with the mask value 0x3f (0b111111). The shift distance
> actually used is therefore always in the range 0 to 63, inclusive.
> {quote}
> and x86 works the same way.
> if we remove this, we just see less instructions with printassembly...
--
This message was sent by Atlassian JIRA
(v6.2#6252)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
