[llvm] [InstCombine] Canonicalize Bit Testing by Shifting to Sign Bit (PR #101822)

[Yingwei Zheng via llvm-commits]

dtcxzyw wrote:

This pattern does not seem to exist in real-world code :(
We already fold `(X << C) < 0` -> `(X u>> (BW - C - 1)) != 0`: https://godbolt.org/z/KnjsKT579



https://github.com/llvm/llvm-project/pull/101822