RFR: 8287794: Reverse*VNode::Identity problem [v4]

[Jatin Bhateja]

On Thu, 28 Jul 2022 06:37:52 GMT, Xiaohong Gong <xgong at openjdk.org> wrote:

>> IR check is not applicable for AVX512,  test point is added to cover transform for SVE which supports direct predicated vector instruction. Feature checks are much more strict and "sve" feature will be available only if UseSVE is set to 1.
>> 
>> Thanks, removed redundant SVE check from IR annotations from other places.
>
> Thanks for updating the tests! I ran the test in our internal testing system,  and unfortunately, this case will fail with "-XX:UseSVE=0" as expected. The reason is actually like what I said above. So to fix this, could you please:
> 
> 1. Limit the whole test on aarch64 os systems by adding "`@requires vm.cpu.features ~= ".*simd.*"`" before the test. And limit the single IR test by adding "`applyIf={"UseSVE", ">0"}`" .
> 
> OR
> 
> 2. Fix the IR framework, to make "applyIf" and "applyIfCPUFeature" can co-work with each other.
> 
> WDYT?

I am not clear, if UseSVE=0 then why does "sve" feature getting populated during VM initialization?
Entire handling of applyIfCPUFeature* is based on white box CPU feature API which queries the feature list populated during VM initialization, we are not directly queries the target features seen in /proc/cpuinfo.

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PR: https://git.openjdk.org/jdk/pull/9623