RFR: 8262096: Vector API fails to work due to VectorShape initialization exception [v3]

[Paul Sandoz]

On Fri, 26 Feb 2021 02:16:02 GMT, Jie Fu <jiefu at openjdk.org> wrote:

>> Thanks, was the test `VectorShapeInitTest` passing prior to the fix of the numerator?
>> Perhaps we should be testing more directly on `VectorShape.S_Max_BIT.vectorBitSize()` and `VectorShape.preferredShape` ? 
>> Also, perhaps we can run with C2 disabled, with `-XX:TieredStopAtLevel=3` ?
>
>> Thanks, was the test `VectorShapeInitTest` passing prior to the fix of the numerator?
> Yes. It also passed with min_lane_count = 64 / type2aelembytes(bt).
> 
>> Perhaps we should be testing more directly on `VectorShape.S_Max_BIT.vectorBitSize()` and `VectorShape.preferredShape` ?
> Ok.
> But it that case, I'd like to just re-use jdk/incubator/vector/PreferredSpeciesTest.java.
> 
>> Also, perhaps we can run with C2 disabled, with `-XX:TieredStopAtLevel=3` ?
> Fine.
> Although this bug wouldn't be triggered with -XX:TieredStopAtLevel=x, it can help test  with C1.
> 
> Patch had been updated.
> Any comments?
> Thanks.

Reusing PreferredSpeciesTest is a good idea.

I now realize that C2 needs to be compiled out to trigger some other cases. In that case I think we can remove the execution with `-XX:TieredStopAtLevel=x`. The test will get executed with various HotSpot configurations by the test infrastructure, eventually...

Looks good.

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PR: https://git.openjdk.java.net/jdk/pull/2722