[llvm] [LV] Add initial legality checks for ee loops with stores (PR #145663)

[David Sherwood via llvm-commits]

david-arm wrote:

Can you expand the commit message please and add more detail? I am aware of how this fits together with your other work, but others may not be. On this PR as well it might be worth adding a link to any other related PR or RFC to explain the motivation.

https://github.com/llvm/llvm-project/pull/145663