[llvm] [DAG] visitCLMUL - fold (clmul x, c_pow2) -> (shl x, log2(c_pow2)) (PR #184049)

[Simon Pilgrim via llvm-commits]

RKSimon wrote:

Sure, makes sense - but we're still going to need it in dag once we start using clmul in bit twiddling expansions

https://github.com/llvm/llvm-project/pull/184049