[LAA] Split out a helper to check the pointer partitions, NFC

This is made a static public member function to allow the transition of
this logic from LAA to LoopDistribution.  (Technically, it could be an
implementation-local static function but then it would not be accessible
from LoopDistribution.)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@242376 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed