[lworld] RFR: 8228361: [lworld] Optimize the substitutability check in C2 [v2]

[Tobias Hartmann]

On Thu, 18 Dec 2025 12:09:58 GMT, Christian Hagedorn <chagedorn at openjdk.org> wrote:

>> Tobias Hartmann has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 21 commits:
>> 
>>  - Merge branch 'lworld' into JDK-8228361
>>  - More refactoring, better comments
>>  - More comments, removing workaround
>>  - Merge
>>  - v5
>>  - Refactoring v4
>>  - Refactoring v3
>>  - Refactoring, more checks, new test
>>  - Merge branch 'lworld' into JDK-8228362
>>  - All tests pass
>>  - ... and 11 more: https://git.openjdk.org/valhalla/compare/3c41c2aa...4f8556c7
>
> src/hotspot/share/opto/inlinetypenode.cpp line 712:
> 
>> 710: 
>> 711:     Node* field_base = base;
>> 712:     Node* field_ptr = ptr;
> 
> To better follow the logic below, I suggest the following names:
> - `val` -> `this_field`
> - `ptr`/`field_ptr` -> `other`/`field_other`. 
> 
> And further down use this/other instead of left/right.

Makes sense, will update code and comments accordingly.

> src/hotspot/share/opto/library_call.cpp line 4424:
> 
>> 4422: }
>> 4423: 
>> 4424: //---------------------------load_mirror_from_klass----------------------------
> 
> Suggestion:

I moved this code back to where it is in mainline and would therefore rather leave it unchanged.

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

PR Review Comment: https://git.openjdk.org/valhalla/pull/1823#discussion_r2631106461
PR Review Comment: https://git.openjdk.org/valhalla/pull/1823#discussion_r2631105692