RFR: 8282722: Regard mapping array in enum switches as stable for constant folding

[Jatin Bhateja]

On Mon, 7 Mar 2022 09:16:45 GMT, Joshua Zhu <jzhu at openjdk.org> wrote:

>> Is there a jmh micro-ben to show the perf improvement?
>> Or a jtreg test to show the inlining effect after this patch?
>> 
>> Copyright year in `fieldInfo.hpp` needs to be updated.
>> 
>> Thanks.
>
>> Is there a jmh micro-ben to show the perf improvement? Or a jtreg test to show the inlining effect after this patch?
>> 
>> Copyright year in `fieldInfo.hpp` needs to be updated.
>> 
>> Thanks.
> 
> Thanks for your comments.
> This change is an optimization workable for all enum switches.
> Please check the example at http://cr.openjdk.java.net/~jzhu/8282722/
> You can check the generated codes or IR graph of function "test2" for differences with/without this change.

Hi @JoshuaZhuwj , Can we also augment mentioned method [1] with a ForceInline attribute.  Since SPECIES itself is static final it's constantness will propagate down to its fields and enable expression folding. But your fix looks generic one.

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PR: https://git.openjdk.java.net/jdk/pull/7721