[llvm] [GlobalISel] Combine (X >> C) << C to X & ((-1 >> C) << C) (PR #114821)

[Thorsten Schütt via llvm-commits]

tschuett wrote:

That the combine is in the SDAG is not a convincing argument. When there are no test changes, the benefit is questionable.

https://github.com/llvm/llvm-project/pull/114821