RFR: 8353290: C2: Refactor PhaseIdealLoop::is_counted_loop() [v6]

[Kangcheng Xu]

On Mon, 16 Jun 2025 15:25:53 GMT, Kangcheng Xu <kxu at openjdk.org> wrote:

>> This PR refactors `PhaseIdealLoop::is_counted_loop()` into (mostly) `CountedLoopConverter::is_counted_loop()` and `CountedLoopConverter::convert()` to decouple the detection and conversion code. This enables us to try different loop configurations easily and finally convert once a counted loop is found. 
>> 
>> A nested `PhaseIdealLoop::CountedLoopConverter` class is created to handle the context, but I'm not if this is the best name or place for it. Please let me know what you think.
>> 
>> Blocks [JDK-8336759](https://bugs.openjdk.org/browse/JDK-8336759).
>
> Kangcheng Xu has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 22 commits:
> 
>  - Merge branch 'master' into counted-loop-refactor
>    
>    # Conflicts:
>    #	src/hotspot/share/opto/loopnode.cpp
>    #	src/hotspot/share/opto/loopnode.hpp
>    #	src/hotspot/share/opto/loopopts.cpp
>  - Merge remote-tracking branch 'origin/master' into counted-loop-refactor
>  - further refactor is_counted_loop() by extracting functions
>  - WIP: refactor is_counted_loop()
>  - WIP: refactor is_counted_loop()
>  - WIP: review followups
>  - reviewer suggested changes
>  - line break
>  - remove TODOs
>  - Revert "improve formatting, naming, comments"
>    
>    This reverts commit fd6071761bdc47ab5695559dffd1e1dd6038d9f7.
>  - ... and 12 more: https://git.openjdk.org/jdk/compare/9d060574...fd93998b

No worries! Enjoy your time off!

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PR Comment: https://git.openjdk.org/jdk/pull/24458#issuecomment-2989397512