RFR: 8298935: fix cyclic dependency bug in create_pack logic in SuperWord::find_adjacent_refs [v9]

[Emanuel Peter]

On Thu, 23 Feb 2023 07:34:00 GMT, Jatin Bhateja <jbhateja at openjdk.org> wrote:

>> Emanuel Peter has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Regression test for Test.java byte case that crashed on arm
>
> test/hotspot/jtreg/compiler/loopopts/superword/TestCyclicDependency.java line 32:
> 
>> 30:  * @requires vm.compiler2.enabled
>> 31:  * @library /test/lib /
>> 32:  * @run driver TestCyclicDependency
> 
> Hi @eme64 , can you extend one of the test point to cover various cases for MaxVectorSizes,  and AlignVector combinations and add multiple IR rules with relevant constraints. 
> e.g.  
>   iArr[ i + 4] = iArr[i];     // Vectorize if MaxVectorSize=16 but for 32/64, +AlignVector
>   iArr[ i + 7] = iArr[i];     // Vectorize for MaxVectorSize=16,  -AlignVector
> 
> PS:  SuperWord operates under SuperWordMaxVectorSize flag.

Yes, it would be interesting to test the flags `SuperWordMaxVectorSize`, `AlignVector` and CompileCommand Directive `Vectorize` in combination (activated / deactivated).

I will create an additional test for that then, and vigorously check it with various IR rules.

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PR: https://git.openjdk.org/jdk/pull/12350