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

[David Sherwood via llvm-commits]

david-arm wrote:

Hi @fhahn @huntergr-arm, I've pushed up a new patch which required fixing conflicts during rebase (again). Although I see it conflicts yet again - hard to keep standing still! :(

This patch now effectively contains #96752 and I will also create a new PR for the standalone addition of `isDereferenceableReadOnlyLoop`. Once these two separate PRs land it will make this patch a bit smaller.

Almost all of the LoopAccessAnalysis changes have gone, with the logic for determining whether a loop will fault moved to LoopVectorizationLegality. Similarly, the code to track exiting blocks has moved there too.

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