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https://issues.apache.org/jira/browse/HIVE-10238?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14483915#comment-14483915
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Mostafa Mokhtar commented on HIVE-10238:
----------------------------------------
[~chengxiang li]
I have been trying to find a substitute in Java to mix boolean expression with
arithmetic without any luck.
I wanted to change code from this
{code}
for(int j=i=0; i<n; i++)
if (col[i] < val) res[j++] = i;
{code}
To this, which is not possible in Java, the code below removes the branch but
still has data dependency which can't be unrolled.
{code}
int j;
for(int j=i=0; i<n; i++)
j += (col[i] < val);
res[j++] = i;
{code}
> 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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