RFR: 8322077: Add Ideal transformation: (~a) | (~b) => ~(a & b) [v2]

Quan Anh Mai qamai at openjdk.org
Thu Dec 14 18:09:40 UTC 2023


On Thu, 14 Dec 2023 17:46:59 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:
> 
>   include bug id.

LGTM, but may you consider having dedicated functions to check and create `Not` patterns? Thanks a lot.

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PR Comment: https://git.openjdk.org/jdk/pull/16334#issuecomment-1856343282


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