[llvm] [IR] Add llvm `clmul` intrinsic (PR #140301)

[Jan Schultke via llvm-commits]

eisenwave wrote:

It may also be worth noting that C++29 will almost certainly have `std::bit_compress` and `std::bit_expand`, corresponding to `pext` and `pdep` instructions. The generic implementation of these functions also involves carry-less multiplication (if available).

See https://github.com/llvm/llvm-project/issues/172857#issuecomment-3670730503

https://github.com/llvm/llvm-project/pull/140301