[lworld] Integrated: 8375434: [lworld] Add comment for null-check in InlineKlass::read_payload_from_addr

[Joel Sikström]

On Thu, 15 Jan 2026 11:58:34 GMT, Joel Sikström <jsikstro at openjdk.org> wrote:

> Hello,
> 
> Update: There is nothing wrong with the logic. I added a comment to clarify why the second null-marker check is needed. Thanks.
> 
> ~~Right now we check the null-marker for the NULLABLE_ATOMIC_FLAT LayoutKind twice, both before and after allocating a heap instance. The first check returns nullptr early if the null-marker is set, as we don't have to allocate an object on the heap if we are going to return nullptr anyways. The other check is redundant, since if the null-marker is not set, the source object is non-null, which means the destination (res) object is non-null as well after copying, so the code inside it is unreachable.~~
> 
> Testing:
> * Oracle's tier1-4, hotspot_valhalla, jdk_valhalla
> * ~~I also added a `gurantee` for the removed code and ran through hotspot_valhalla and jdk_valhalla locally.~~

This pull request has now been integrated.

Changeset: a4fb7ebd
Author:    Joel Sikström <jsikstro at openjdk.org>
Committer: Paul Hübner <phubner at openjdk.org>
URL:       https://git.openjdk.org/valhalla/commit/a4fb7ebd5af316d3e99d10bffb44d5be3aab5548
Stats:     10 lines in 1 file changed: 7 ins; 0 del; 3 mod

8375434: [lworld] Add comment for null-check in InlineKlass::read_payload_from_addr

Reviewed-by: fparain, phubner

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PR: https://git.openjdk.org/valhalla/pull/1914