RFR: 8306075: Micro-optimize Enum.hashCode [v2]

Mon Apr 17 13:43:44 UTC 2023

On Mon, 17 Apr 2023 13:27:43 GMT, olivergillespie <duke at openjdk.org> wrote:

> > Why isn't `Enum::hashCode` simply doing `return ordinal;`?
> 
> See https://bugs.openjdk.org/browse/JDK-8050217

Thanks! If there are apps where `Enum::hashCode` is performance sensitive then run-to-run stability may be a stronger argument than @stuart-marks et al argues it is here, though there might be some unspoken arguments about how it might affect iteration order et.c... 

Adding a cached field to `Enum` seem innocuous though, whether it disappears into a padding gap or not.

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PR Comment: https://git.openjdk.org/jdk/pull/13491#issuecomment-1511370298