[llvm-branch-commits] [llvm] [SelectionDAG] Legalize <1 x T> vector types for atomic load (PR #120385)

[Matt Arsenault via llvm-branch-commits]

arsenm wrote:

> crashes with:
> 
> ```
> WidenVectorResult #0: t3: v2i32,ch = AtomicLoad<(load acquire (s64) from %ir.x, align 64)> t0, t2
> LLVM ERROR: Do not know how to widen the result of this operator!
> ```

At this PR, this is the expectation. A later PR needs to handle the other vector legalization cases 

https://github.com/llvm/llvm-project/pull/120385