RFR: 8283894: Intrinsify compress and expand bits on x86 [v8]

[John R Rose]

On Mon, 30 May 2022 06:56:27 GMT, Jatin Bhateja <jbhateja at openjdk.org> wrote:

>> Summary of changes:
>> 
>> - Patch intrinsifies following newly added Java SE APIs
>>   - Integer.compress
>>   - Integer.expand
>>   - Long.compress
>>   - Long.expand
>>   
>> - Adds C2 IR nodes and corresponding ideal transformations for new operations.
>> - We see around ~10x performance speedup due to intrinsification over X86 target. 
>> - Adds an IR framework based test to validate newly introduced IR transformations.
>> 
>> Kindly review and share your feedback.
>> 
>> Best Regards,
>> Jatin
>
> Jatin Bhateja has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 12 additional commits since the last revision:
> 
>  - Merge branch 'master' of http://github.com/openjdk/jdk into JDK-8283894
>  - 8283894: Extending new IR value routines with value propagation logic.
>  - 8283894: Disabling sanity test as per review suggestion.
>  - Merge branch 'master' of http://github.com/openjdk/jdk into JDK-8283894
>  - 8283894: Removing CompressExpandSanityTest from problem list.
>  - 8283894: Updating test tag spec.
>  - 8283894: Review comments resolved.
>  - 8283894: Add missing -XX:+UnlockDiagnosticVMOptions.
>  - 8283894: Review comments resolutions.
>  - Merge branch 'master' of http://github.com/openjdk/jdk into JDK-8283894
>  - ... and 2 more: https://git.openjdk.java.net/jdk/compare/0b6737d2...a36dba2e

Yes.  Thank you.

Final suggestion:  Factor out 2 blocks of code that implement compress and expand, for C2 constant folding (Value methods), into 2 static routines.  Maybe throw in a static assert for a smoke check on those factored routines.

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Marked as reviewed by jrose (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/8498