RFR: 8325467: Support methods with many arguments in C2 [v23]

[Daniel Lundén]

On Wed, 17 Sep 2025 09:56:16 GMT, Daniel Lundén <dlunden at openjdk.org> wrote:

>> @dlunde Thanks for the swift updates! I have in the meantime added some more comments, just making sure you don't miss them :)
>
> @eme64
> 
>> You seem to have a build failure:
>> 
>> ```
>> In file included from /home/runner/work/jdk/jdk/src/hotspot/share/opto/compile.hpp:43,
>>                  from /home/runner/work/jdk/jdk/src/hotspot/share/opto/type.hpp:29,
>>                  from /home/runner/work/jdk/jdk/test/hotspot/gtest/opto/test_rangeinference.cpp:26:
>> /home/runner/work/jdk/jdk/src/hotspot/share/opto/regmask.hpp: In constructor ‘RegMask::RegMask(Arena*)’:
>> /home/runner/work/jdk/jdk/src/hotspot/share/opto/regmask.hpp:441:53: error: class ‘RegMask’ does not have any field named ‘_read_only’
>>   441 |       : _rm_word() DEBUG_ONLY(COMMA _arena(arena)), _read_only(read_only),
>>       |                                                     ^~~~~~~~~~
>> /home/runner/work/jdk/jdk/src/hotspot/share/opto/regmask.hpp:441:64: error: ‘read_only’ was not declared in this scope
>>   441 |       : _rm_word() DEBUG_ONLY(COMMA _arena(arena)), _read_only(read_only),
>>       |     
>> ```
> 
> Thanks, only failed on release so didn't notice. Will fix.
> 
>> I really appreciate that you added extensive `gtest`s, thanks for that 😊
> 
> @robcasloz contributed 90% of that, so the credit goes to him!
> 
>> And thanks for using the Template Framework, I'm curious to hear if you have any feedback on it :)
> 
> Sure, it was quite convenient. Happy to talk about the experience offline.

> @dlunde I just had another look through the whole code change. And I'm very happy with it now. Especially the additional code comments around `rollover`/`offset` really helped to bring it together for me :)
> 
> Thanks for bearing with me through the many comments / suggestions 😊
> 
> I would suggest that either @vnkozlov or @robcasloz have another quick look over the changes, just to see if they agree with what we have been doing ;)

Thank you @eme64 , much appreciated! I agree we have improved the changeset a lot from the initial version. Yes, @robcasloz has let me know he will have a look at the changes soon. @vnkozlov is also welcome to review again of course, but his previous review is for a very much out-of-date version of the changeset.

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PR Comment: https://git.openjdk.org/jdk/pull/20404#issuecomment-3312059287