[lworld] RFR: 8349110: [lworld] Intrinsics for Unsafe.get/putFlatValue

[Quan Anh Mai]

On Thu, 12 Jun 2025 11:22:28 GMT, Tobias Hartmann <thartmann at openjdk.org> wrote:

>> Hi,
>> 
>> This PR implements intrinsics for `Unsafe::get/putFlatValue` and enables the corresponding tests in `TestIntrinsics`.
>> 
>> Please kindly review, thanks very much.
>
> I also noticed that there are still two leftover ToDos from JDK-8239003 in TestIntrinsics. I think `test54` should be removed because C2 will bail out from compilation. I quickly checked and it also seems that we can re-enable the test with `-XX:+DeoptimizeALot` again.

@TobiHartmann It was because I need to buffer the `InlineTypeNode` if a load is required, I have added necessary handling for `InlineTypeNode`. For the TODOs in `TestIntrinsics`, `test54` seems like it can be removed since it tries to pass a larval value object to another method, `test79` and `test84` can be reenabled. For `test84`, I think an allocation is still necessary for the return value, so I remove that IR condition.

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PR Comment: https://git.openjdk.org/valhalla/pull/1482#issuecomment-2971987447