RFR: 8323497: On x64, use 32-bit immediate moves for narrow klass base if possible [v5]

Fri May 23 15:54:54 UTC 2025

On Fri, 23 May 2025 15:32:43 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

>>> Well, every little bit counts.
>> 
>> `0.6..1.0%` improvement in code density is great for such a small change. This is why I want it sooner :)
>
> Thank you @shipilev. I will wait for a second review and for @vnkozlov to finish his tests.

@tstuefe  Did you run with COH as you planned? 

My other concern is AOT code caching where we need relocation. But we can use separate code branch for that as we did in `encode_klass_not_null()`.

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PR Comment: https://git.openjdk.org/jdk/pull/17340#issuecomment-2904913785