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From "Chengxiang Li (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HIVE-10238) Loop optimization for SIMD in IfExprColumnColumn.txt
Date Wed, 08 Apr 2015 03:07:12 GMT

    [ https://issues.apache.org/jira/browse/HIVE-10238?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14484627#comment-14484627
] 

Chengxiang Li commented on HIVE-10238:
--------------------------------------

Yes, [~mmokhtar], I don't see how to remove the data dependency in this loop either.

> Loop optimization for SIMD in IfExprColumnColumn.txt
> ----------------------------------------------------
>
>                 Key: HIVE-10238
>                 URL: https://issues.apache.org/jira/browse/HIVE-10238
>             Project: Hive
>          Issue Type: Sub-task
>          Components: Vectorization
>    Affects Versions: 1.1.0
>            Reporter: Chengxiang Li
>            Priority: Minor
>
> The ?: operator as following could not be vectorized in loop, we may transfer it into
mathematical expression.
> {code:java}
> for(int j = 0; j != n; j++) {
>       int i = sel[j];
>       outputVector[i] = (vector1[i] == 1 ? vector2[i] : vector3[i]);
>       outputIsNull[i] = (vector1[i] == 1 ?
>           arg2ColVector.isNull[i] : arg3ColVector.isNull[i]);
> }
> {code} 



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