[llvm] [InstCombine] Remove `sub nuw C_Mask, X` -> `xor X, C_Mask` canoncalization (PR #122607)

[Nikita Popov via llvm-commits]

nikic wrote:

Are you sure this is worth pursuing? I expect this is going to be something of a mixed bag even after some effort to mitigate regressions. Note that the llvm-opt-benchmark results seem to be the same before and after you added a bunch of XorLike checks, so I'm not sure that direction is really helpful to mitigate regressions in practice (and we should not perform a mass-conversion without evidence that it is).

https://github.com/llvm/llvm-project/pull/122607