[llvm] [InstCombine] Fold ((X + AddC) & Mask) ^ Mask to ((Mask - AddC) - X) & Mask (PR #174278)

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ParkHanbum wrote:

Ah, so that's how it happened. As the submitter of this patch, I should have provided a clear answer, but I failed to do so, and as a result, I took up too much of your time. I sincerely apologize. @antoniofrighetto @dtcxzyw 

https://github.com/llvm/llvm-project/pull/174278