[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.)

llvm-svn: 242376

include/llvm/Analysis/LoopAccessAnalysis.h

@@ -405,6 +405,14 @@ public:
   /// Holds a partitioning of pointers into "check groups".
   SmallVector<CheckingPtrGroup, 2> CheckingGroups;
 
+  /// \brief Check if pointers are in the same partition
+  ///
+  /// \p PtrToPartition contains the partition number for pointers (-1 if the
+  /// pointer belongs to multiple partitions).
+  static bool
+  arePointersInSamePartition(const SmallVectorImpl<int> &PtrToPartition,
+                             unsigned PtrIdx1, unsigned PtrIdx2);
+
 private:
   /// \brief Decide whether we need to issue a run-time check for pointer at
   /// index \p I and \p J to prove their independence.

lib/Analysis/LoopAccessAnalysis.cpp

@@ -280,6 +280,13 @@ void RuntimePointerChecking::groupChecks(
   }
 }
 
+bool RuntimePointerChecking::arePointersInSamePartition(
+    const SmallVectorImpl<int> &PtrToPartition, unsigned PtrIdx1,
+    unsigned PtrIdx2) {
+  return (PtrToPartition[PtrIdx1] != -1 &&
+          PtrToPartition[PtrIdx1] == PtrToPartition[PtrIdx2]);
+}
+
 bool RuntimePointerChecking::needsChecking(
     unsigned I, unsigned J, const SmallVectorImpl<int> *PtrPartition) const {
   const PointerInfo &PointerI = Pointers[I];
@@ -298,10 +305,7 @@ bool RuntimePointerChecking::needsChecking(
     return false;
 
   // If PtrPartition is set omit checks between pointers of the same partition.
-  // Partition number -1 means that the pointer is used in multiple partitions.
-  // In this case we can't omit the check.
-  if (PtrPartition && (*PtrPartition)[I] != -1 &&
-      (*PtrPartition)[I] == (*PtrPartition)[J])
+  if (PtrPartition && arePointersInSamePartition(*PtrPartition, I, J))
     return false;
 
   return true;