[llvm] [X86] Combine `PTEST` to `TESTP` (PR #157249)

[Simon Pilgrim via llvm-commits]

https://github.com/RKSimon commented:

We already have a similar fold in combinePTESTCC that uses SimplifyMultipleUseDemandedBits - any idea why it isn't firing?

https://github.com/llvm/llvm-project/pull/157249