[llvm] [AMDGPU] - Generate s_bitreplicate_b64_b32 (PR #69209)

[Jessica Del via llvm-commits]

OutOfCache wrote:

Is there a way to add a test demonstrating this behavior or is that not possible/necessary? I could add the IR test based on this scenario, but is that enough to prove the illegality of the transform?

https://github.com/llvm/llvm-project/pull/69209