[llvm] [LoopVectorize] Support vectorization of compressing patterns (PR #214491)

[Luke Lau via llvm-commits]

https://github.com/lukel97 commented:

Can you add a RISC-V test too? It can lower the compressed store/load intrinsics, would be good to check that the TTI is plumbed up correctly for it as well

https://github.com/llvm/llvm-project/pull/214491