On Thu, 15 Jan 2026 11:58:34 GMT, Joel Sikström <[email protected]> wrote:

> Hello,
> 
> 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.

Adding a comment to explain the rational of the second null-marker check is a 
good idea.

-------------

PR Comment: https://git.openjdk.org/valhalla/pull/1914#issuecomment-3755298238

Reply via email to