[llvm] [AMDGPU] SelectionDAG support for vector type set 0 to multiple sgpr64 (PR #128017)

[Matt Arsenault via llvm-commits]

https://github.com/arsenm commented:

The set of peephole opt patches I'm working on improve some of these type of situations.

You also have a number of regressions in the VALU cases. Should do something about those (which may mean not doing this for VALU values). Also should consider v_mov_b64 on gfx940 

https://github.com/llvm/llvm-project/pull/128017