[llvm] [TargetLowering][RISCV] Avoid ISD::MUL in expandCLMUL if hasBitTest or MUL requires a library call. (PR #182389)

[Craig Topper via llvm-commits]

topperc wrote:

> > Can this be merged with the incoming bittest lowering patch?
> 
> Yeah. I wasn't quite sure how to do that since there are still outstanding comments over there.

I've taken the RISC-V Zbs RUN lines from that PR and added a corrected hasBitTest call. The Zbc RUN lines are covered by other test files. I split the RISC-V test into 3 tests in hopes that github's web interface would be happier about displaying it. I will give co-credit to the patch author.

https://github.com/llvm/llvm-project/pull/182389