[llvm] [AMDGPU][MC] Allow op_sel in v_alignbit_b32 etc in GFX9 and GFX10 (PR #142188)

[Stanislav Mekhanoshin via llvm-commits]

https://github.com/rampitec approved this pull request.

Ok, I see this is supported: `V_ALIGNBIT_B32 v1, v2, v3, v4.h`.
I guess S2 in this case is v4.h.
LGTM.

https://github.com/llvm/llvm-project/pull/142188