RFR: 8349361: C2: RShiftL should support all applicable transformations that RShiftI does [v14]

[Emanuel Peter]

On Thu, 13 Mar 2025 16:37:01 GMT, Roland Westrelin <roland at openjdk.org> wrote:

>> This change refactors `RShiftI`/`RshiftL` `Ideal`, `Identity` and
>> `Value` because the `int` and `long` versions are very similar and so
>> there's no logic duplication. In the process, support for some extra
>> transformations is added to `RShiftL`. I also added some new test
>> cases.
>
> Roland Westrelin has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 30 additional commits since the last revision:
> 
>  - test with Long.Min/Long.Max + CONST64
>  - Merge branch 'master' into JDK-8349361
>  - review
>  - Update src/hotspot/share/opto/mulnode.cpp
>    
>    Co-authored-by: Christian Hagedorn <christian.hagedorn at oracle.com>
>  - Update src/hotspot/share/opto/mulnode.hpp
>    
>    Co-authored-by: Christian Hagedorn <christian.hagedorn at oracle.com>
>  - Update src/hotspot/share/opto/mulnode.cpp
>    
>    Co-authored-by: Christian Hagedorn <christian.hagedorn at oracle.com>
>  - Update src/hotspot/share/opto/mulnode.cpp
>    
>    Co-authored-by: Christian Hagedorn <christian.hagedorn at oracle.com>
>  - Update src/hotspot/share/opto/mulnode.cpp
>    
>    Co-authored-by: Christian Hagedorn <christian.hagedorn at oracle.com>
>  - Update test/hotspot/jtreg/compiler/c2/irTests/RShiftLNodeIdealizationTests.java
>    
>    Co-authored-by: Emanuel Peter <emanuel.peter at oracle.com>
>  - Update src/hotspot/share/opto/mulnode.cpp
>    
>    Co-authored-by: Emanuel Peter <emanuel.peter at oracle.com>
>  - ... and 20 more: https://git.openjdk.org/jdk/compare/cee04e4f...a56e397b

Gave it a quick pass again, I think this is good to go (though better to integrate after the weekend...) 

@rwestrel thanks for the work and all the updates ☺

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

Marked as reviewed by epeter (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/23438#pullrequestreview-2705956672