[vectorIntrinsics] RFR: 8283413: Add C2 mid-end and x86 back-end implementation for bit REVERSE and REVERSE_BYTES operation [v8]

[Eric Liu]

On Fri, 8 Apr 2022 17:00:39 GMT, Paul Sandoz <psandoz at openjdk.org> wrote:

>> Jatin Bhateja has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   8283413: Adding strict constraints for Reverse/ReverseBytes related transformation.
>
> Internal tests on `aarch64` debug builds show this integration causes `*{64, 128, MAX}VectorTests` tests to crash with the same internal error (AFAICT):
> 
> ...
> # A fatal error has been detected by the Java Runtime Environment:
> #
> #  Internal Error (/System/Volumes/Data/mesos/work_dir/slaves/c82600aa-2448-475c-8c08-6f02a5b3f3af-S39291/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/4128da6a-70ed-4297-ada9-9dcf07a4eb36/runs/0a4f78a7-fce4-49b5-b1d0-143d8a80fbda/workspace/open/src/hotspot/share/opto/node.hpp:814), pid=10360, tid=42243
> #  assert(fl <= max_flags()) failed: invalid node flag
> ...

@PaulSandoz Thanks for your feedback. I think it can be fixed with related AArch64 patch, it's coming soon.

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PR: https://git.openjdk.java.net/panama-vector/pull/182