[llvm] [VPlan] Lower safe uniform load to unconditional scalar load (PR #216767)

[Luke Lau via llvm-commits]

https://github.com/lukel97 commented:

> Would it make sense to canonicalize zero-stride loads to scalar load + broadcast?

Yeah I think actually given that vp.strided.load isn't legal on every target, the scalar load + broadcast form seems sensible to lower to first. We can teach convertToStridedAccesses to handle the scalar pattern separately. So I think I've changed my mind and the approach in this PR makes sense, sorry for the confusion!

https://github.com/llvm/llvm-project/pull/216767