RFR: 8160821: VarHandle accesses are penalized when argument conversion is required [v9]

[Chen Liang]

On Wed, 10 Dec 2025 22:13:23 GMT, Vladimir Ivanov <vlivanov at openjdk.org> wrote:

>> I think that is when two different VarHandles are both invoked non-exactly in two call sites in one method, the 2nd one fails to be inlined, that the compare-and-exchange from the 2nd one is not present in the final IR. The deoptimization reason is either "unstable-if" or "too many null checks", I think I will try look into it in another effort.
>
> If it's a test problem, then it's better to comment out the problematic test case instead.

I have diagnosed the reason, updated the comments, and added a benchmark to showcase this.

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PR Review Comment: https://git.openjdk.org/jdk/pull/28585#discussion_r2620294345