Don't allocate empty read-only SmallVectors during SelectionDAG deallocation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133348 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp b/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
index 0d656ef..dbc623b 100644
--- a/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
+++ b/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
@@ -649,7 +649,7 @@
   // order number right after the N.
   MachineBasicBlock *BB = Emitter.getBlock();
   MachineBasicBlock::iterator InsertPos = Emitter.getInsertPos();
-  SmallVector<SDDbgValue*,2> &DVs = DAG->GetDbgValues(N);
+  ArrayRef<SDDbgValue*> DVs = DAG->GetDbgValues(N);
   for (unsigned i = 0, e = DVs.size(); i != e; ++i) {
     if (DVs[i]->isInvalidated())
       continue;