[llvm] [RISCV] Add DAG combine to convert (iX ctpop (bitcast (vXi1 A))) into vcpop.m. (PR #117062)

[Luke Lau via llvm-commits]

https://github.com/lukel97 commented:

LGTM. I don't have any better ideas for dealing with illegal types. 

https://github.com/llvm/llvm-project/pull/117062