RFR: JDK-8314890: Reduce number of loads for Klass decoding in static code [v2]

[Thomas Stuefe]

On Thu, 24 Aug 2023 08:58:35 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> I see a few other places where `UseCompressedClassPointers` is used: `oopDesc::load_klass_raw` and `oopDesc::has_klass_gap`. Both seem to be only used from the diagnostic code, so their performance might not be relevant. Should those keep being omitted?
> 
> All other uses I see are in either compiler code (where we can afford reading the flag directly) or non-perf-critical parts of runtime.

It probably won't matter either way. The compiler side I may touch with later patches. For the rest, I'd like to keep the patch small and confined.

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PR Comment: https://git.openjdk.org/jdk/pull/15389#issuecomment-1691324239