[llvm] [LoopInterchange] Exit early when all loops have deps in all directions (PR #149049)

[Ryotaro Kasuga via llvm-commits]

kasuga-fj wrote:

compile-time improvements: https://llvm-compile-time-tracker.com/compare.php?from=23e0caaa5d346bdc16ee579504b90a723771860a&to=2cba425f2096f8314bc064fe7d42700dec193ed6&stat=instructions:u

https://github.com/llvm/llvm-project/pull/149049