[llvm] [AMDGPU][GlobalISel] Add readanylane combines for merge-like instruct… (PR #172546)

[Petar Avramovic via llvm-commits]

https://github.com/petar-avramovic commented:

LGTM, have a few suggestions for nicer indentation and shorted comments

https://github.com/llvm/llvm-project/pull/172546