RFR: 8322077: Add Ideal transformation: (~a) | (~b) => ~(a & b) [v4]

[Tobias Hartmann]

On Fri, 15 Dec 2023 23:35:56 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 incrementally with one additional commit since the last revision:
> 
>   untabify.

Looks good to me. Please update the copyright dates.

I submitted testing and will report back once it passed.

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PR Review: https://git.openjdk.org/jdk/pull/16334#pullrequestreview-1805744288