[llvm] [X86, CodeGen] Add a pattern in PreprocessISelDAG. (PR #85848)

[Peter Rong via llvm-commits]

DataCorrupted wrote:

> SimplifyShift would be the best place to handle this.
> 
> I had almost finished a patch for this, why didn't you assign the ticket?

Cool, thanks! I just assigned it to you. Shall I close this PR?

https://github.com/llvm/llvm-project/pull/85848