[llvm] Reland `[CodeGenPrepare] Convert `ctpop(X) ==/!= 1` into `ctpop(X) u</u> 2/1` (#111284)` (PR #111998)

[Yingwei Zheng via llvm-commits]

dtcxzyw wrote:

I decide to block this pr until https://github.com/llvm/llvm-project/issues/112078 is fixed.


https://github.com/llvm/llvm-project/pull/111998