[llvm] [clang] [clang-tools-extra] [AArch64] Add an AArch64 pass for loop idiom transformations (PR #72273)

[David Green via cfe-commits]

https://github.com/davemgreen approved this pull request.

Thanks for the updates. From what I can tell this LGTM, but it will need a rebase.

You might want to commit it with the option disabled, and then flip the switch in a followup to avoid the commit-revert cycles in case there are any issues.

https://github.com/llvm/llvm-project/pull/72273