RFR: 8370914: C2: Reimplement Type::join [v4]

Wed Jan 7 18:05:55 UTC 2026

On Fri, 21 Nov 2025 09:13:29 GMT, Marc Chevalier <mchevalier at openjdk.org> wrote:

>> Quan Anh Mai has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains five commits:
>> 
>>  - Merge branch 'master' into typejoin
>>  - Move dual to ASSERT only
>>  - Keep old version for verification
>>  - whitespace
>>  - Reimplement Type::join
>
> We probably need associativity, but then, if we have an abstract domain that is a lattice, that should be rather straightforward. If we start having simple posets instead, we can be very sound, but associativity might require more care...

@marc-chevalier Thanks for your reviews. I have addressed and responded to your concerns.

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

PR Comment: https://git.openjdk.org/jdk/pull/28051#issuecomment-3720085865