RFR: 8322077: Add Ideal transformation: (~a) | (~b) => ~(a & b) [v11]

[Emanuel Peter]

On Tue, 9 Jan 2024 06:06:51 GMT, Zhiqiang Zang <duke at openjdk.org> wrote:

>> Hello,
>> 
>> (~a) | (~b) => ~(a & b) is a widely seen pattern, for example it is implemented for LLVM [here](https://github.com/llvm/llvm-project/blob/397f1ce9efb4eea1ee10fe4833f733b8c7abd878/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp#L1617C28-L1617C28); however it is missing in current implementation of hotspot. This pull request adds this transformation and associated tests.
>> 
>> Thanks.
>
> Zhiqiang Zang 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 14 additional commits since the last revision:
> 
>  - adapt to new changes from the dependant pr.
>  - Merge branch 'andnode-PNewDeMorganLawAndToOr' into ornode-PNewDeMorganLawOrToAnd
>  - adapt changes from the dependent pr.
>  - Merge branch 'andnode-PNewDeMorganLawAndToOr' into ornode-PNewDeMorganLawOrToAnd
>  - Update test/hotspot/jtreg/compiler/c2/irTests/DeMorganLawLongTests.java
>    
>    Co-authored-by: Tobias Hartmann <tobias.hartmann at oracle.com>
>  - Update test/hotspot/jtreg/compiler/c2/irTests/DeMorganLawIntTests.java
>    
>    Co-authored-by: Tobias Hartmann <tobias.hartmann at oracle.com>
>  - Add tests for using De Morgan's Law for both optimizations.
>  - remove unused code from tests.
>  - update the copyright dates.
>  - address comments.
>  - ... and 4 more: https://git.openjdk.org/jdk/compare/25f84663...b21e242b

LGTM, and thanks for the work!

Please only integrate this once your other change is integrated, and merged into this one. Then wait for GHA to complete, and run your own testing.

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

Marked as reviewed by epeter (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/16334#pullrequestreview-1811210531