[llvm] [LV] Add initial legality checks for loops with unbound loads. (PR #152422)

[David Sherwood via llvm-commits]

david-arm wrote:

If you're interested I tried to solve this in a different way (https://github.com/llvm/llvm-project/pull/120603) using loop versioning based on alignment of the loads in the loop. However, this was rejected due to an undocumented feature of normal IR loads. Using different intrinsics with their own semantics certainly solves this problem!

https://github.com/llvm/llvm-project/pull/152422