[lworld] RFR: 8279624: [lworld] interpreter should avoid value copies in withfield when possible [v2]

[Frederic Parain]

On Fri, 7 Jan 2022 18:35:30 GMT, Frederic Parain <fparain at openjdk.org> wrote:

>> Please review this small change to reduce the number of copies the interpreter does when executing the withfield bytecode.
>> If the new value of the field to be updated is identical to the old value of the field, the interpreter simply returns the original value instance instead of creating a new copy.
>> This change removes more than 8K value copies when running the hotspot_valhalla test suite.
>> 
>> Tested with Mach5, tiers 1 to 3.
>> 
>> Thank you
>> 
>> Fred
>
> Frederic Parain has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Add support for floating point fields

Thank you for the review.

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PR: https://git.openjdk.java.net/valhalla/pull/595