RFR: 8369039: JDK-8348611 caused regression in Javac-Hot-Generate [v3]

[Claes Redestad]

On Tue, 7 Oct 2025 18:22:43 GMT, Archie Cobbs <acobbs at openjdk.org> wrote:

>> The refactoring in [JDK-8348611](https://bugs.openjdk.org/browse/JDK-8348611) caused a regression in compiler performance. In the the refactoring there were a couple of simple optimizations that were missed. When put in place, these seem to (mostly) address the performance issue.
>
> Archie Cobbs has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Do more desugaring of Stream and Optional.

Latest look good on both score and allocation pressure, e.g., on my M1 MacBook:

Name       Cnt   Base   Error    Test   Error Unit  Change
compileHot  10 15.915 ± 0.094  14.463 ± 0.235 s/op   1.10x (p = 0.000*)
  * = significant

Allocations: 16.9GB/op -> 13.95GB/op

26-b11 for reference on the same system: 14,285 ± 0,379 s/op
Allocations 14.2GB/op 

So more or less recuperated on score and with slightly less allocation pressure to boot 👍

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PR Comment: https://git.openjdk.org/jdk/pull/27651#issuecomment-3380473533