[LoopDist] Add some runtime checks for cross partition loads - p2

Add back in getInstructionsForAccess as query for Instructions modifying
memory to mark cross partition accesses.

Author: mcberg2021

llvm/lib/Transforms/Scalar/LoopDistribute.cpp

@@ -527,14 +527,31 @@ class InstPartitionContainer {
         if (Ptr->hasOneUse() || Partition == -1)
           continue;
 
-        for (User *U : Ptr->users())
-          if (auto *CurLoad = dyn_cast<LoadInst>(U))
-            if (L->contains(CurLoad->getParent()))
-              if (Partition != (int)this->InstToPartitionId[CurLoad]) {
-                // -1 means belonging to multiple partitions.
-                Partition = -1;
-                break;
-              }
+        bool ProcessLoads = false;
+        for (auto *U : Ptr->users()) {
+          auto *CurLoad = dyn_cast<LoadInst>(U);
+          if (!CurLoad)
+            continue;
+          if (!L->contains(CurLoad->getParent()))
+            continue;
+
+          ProcessLoads = true;
+          break;
+        }
+
+        if (!ProcessLoads)
+          continue;
+
+        const bool IsWritePtr = false;
+        auto ReadInstructions = LAI.getInstructionsForAccess(Ptr, IsWritePtr);
+        for (Instruction *ReadInst : ReadInstructions) {
+          if (Partition == (int)this->InstToPartitionId[ReadInst])
+            continue;
+
+          // -1 means belonging to multiple partitions.
+          Partition = -1;
+          break;
+        }
       }
     }