[llvm] [NFC][LV]: Differentiate between Pred and Unpred masked operations. (PR #169509)

[David Sherwood via llvm-commits]

david-arm wrote:

I think the problem is more than just for preventing legacy cost model asserts. When tail-folding all loads and stores become masked and whereas the cost model may say loads and stores are legal in the main vector loop (because they aren't tail-folded), they may be illegal in the vector epilogue (due to tail-folding). Hence, the cost model for the main and epilogue vector loops need to ask different questions.

https://github.com/llvm/llvm-project/pull/169509