[llvm] [LoopVectorize] Add support for vectorisation of more early exit loops (PR #88385)

[David Sherwood via llvm-commits]

david-arm wrote:

I have rebased on top of HEAD of LLVM, which contains some of Florian's recent changes to LoopAccessAnalysis to generalise all loops to use the symbolic maximum. This required a significant rewrite of the patch, and rebasing/merging to keep all of the commit history was practically impossible. Instead I've simply forced an update with a single new commit.

https://github.com/llvm/llvm-project/pull/88385