[llvm] [LV] Clang-format some loop vectorizer files (PR #158507)

[Tobias Stadler via llvm-commits]

tobias-stadler wrote:

Our coding guidelines prefer not to reformat entire files, because it pollutes the `git blame` history. You can use `git clang-format` to only format the changed code. There's more info at https://llvm.org/docs/Contributing.html#how-to-submit-a-patch

https://github.com/llvm/llvm-project/pull/158507