[lworld] RFR: 8352647: [lworld] Remove larval InlineTypeNode in Unsafe intrinsics [v5]

[Quan Anh Mai]

On Wed, 26 Mar 2025 08:48:53 GMT, Tobias Hartmann <thartmann at openjdk.org> wrote:

>> We should also emit the IR to mark the larval bit in the object header.
>> https://github.com/openjdk/valhalla/blob/lworld%2Bvector/src/hotspot/share/opto/inlinetypenode.cpp#L1075
>
> I wonder if we really still need the larval bit? Does it have any use other than in assertions?

@TobiHartmann I'm not sure, currently the larval bit does not seem to have any use, but maybe in the future the runtime could try to deduplicate value objects. In that case, IMO we don't actually need to have an exact value of the larval-ness but only a conservative value answering the question "Is this object definitely a non-larval value object?"

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PR Review Comment: https://git.openjdk.org/valhalla/pull/1406#discussion_r2030548372