[llvm] [LV] Use SCEV loop-uniformity for outer-loop branch legality (PR #199632)

[Ming Yan via llvm-commits]

https://github.com/NexMing commented:

Sorry for the late reply. The [outer-loop vectorization](https://lists.llvm.org/pipermail/llvm-dev/2017-December/119523.html) has made little progress since it was first proposed.
This patch is intended to improve outer-loop vectorization. It makes the requirements for vectorization less restrictive.

https://github.com/llvm/llvm-project/pull/199632