[master] RFR: 8303813: [Lilliput] (AArch64) Use tbz instead of tst and br in load_klass() [v2]

[Roman Kennke]

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On Thu, 9 Mar 2023 16:29:10 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

> Looks good. "fast" is close enough for TBZ.
> 
> You can adapt the comment now; remove the "clobbers condition flags".

Will do.

> Question, you are not concerned here with avoiding branches for the fast path? Is this less of a problem with arm64?

I am, very much. I found that some workloads are regressing close to 10% because of forward-branches in load-klass code path. However, the code in MacroAssembler is only used for interpreter and other various code paths, but not for C1 and C2. The latter have their own implementation and there we are using stubs.

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PR: https://git.openjdk.org/lilliput/pull/78