[llvm] [SelectionDAG] Legalize vector types for atomic load (PR #111414)

[Matt Arsenault via llvm-commits]

https://github.com/arsenm commented:

codegen parts lgtm, but should avoid manually stacking PRs (which really doesn't work). It's much harder to review, if you want to stack PRs use graphite or spr 

https://github.com/llvm/llvm-project/pull/111414