RFR: 8345485: C2 MergeLoads: merge adjacent array/native memory loads into larger load [v4]

[Kuai Wei]

On Thu, 22 May 2025 06:26:57 GMT, Emanuel Peter <epeter at openjdk.org> wrote:

>> @kuaiwei Thanks for your response!
>> 
>> What about these two things I brought up?
>> 
>>> Do you have some tests where some of the nodes in the load/shift/or expression have other uses?
>> 
>> It would be good to have these tests, even if we think your code is correct. It is good to verify it with tests. And someone in the future might break it.
>> 
>>> I think your implementation should go into OrINode, and match the expression up from there. Because we want to replace the old OrI with the new LoadL.
>> 
>> This is really the pattern we use in `Idea`. We replace the node at the bottom of an expression with a new node (or new expression).
>
>> @eme64 Can we complete the integration in JDK25 before June 5th?
> 
> I've been waiting on a ping from @kuaiwei , since there were still new changes added last week, and I don't know if there are more coming. I'm a little slow with reviewing, as I also have a lot of other work to do and PRs to review. Feel free to find other reviewers to help speed up the process ;)
> 
> Being so close to RDP1 (June 5th) usually makes us a little hesitant to integrate larger features where there is often a bug tail. I would feel better if we could integrate it in early JDK26, and then we have more time to fix the follow-up bugs during JDK26 development.

@eme64 @wenshao I have a little change to this PR. I will send it soon. Thanks for your patience.

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

PR Comment: https://git.openjdk.org/jdk/pull/24023#issuecomment-2900113150