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https://issues.apache.org/jira/browse/HIVE-10238?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14681394#comment-14681394
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Teddy Choi commented on HIVE-10238:
-----------------------------------
Hello [~mmokhtar] and [~chengxiang li].
I think {{LongColumnVector}} can be vectorized with bitwise operators as
following.
{code}
for (int i = 0; i < n; i++) {
outputVector[i] = (~(vector1[i] - 1) & vector2[i]) | ((vector1[i] - 1) &
vector3[i]);
outputIsNull[i] = (vector1[i] & arg2ColVector.isNull[i]) | (vector1[i] ^ 1 &
arg3ColVector.isNull[i]);
}
{code}
As the condition is stored as a long integer, any arithmetic operation with a
floating point needs a type conversion. There's no type conversion
vectorization in Java 8 yet.
(http://hg.openjdk.java.net/jdk8/jdk8/hotspot/rev/006050192a5a) However,
{{outputIsNull}} array still can be vectorized as above.
Thanks.
> 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
> Assignee: 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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