Avoid overly large SmallPtrSet/SmallSet

These sets perform linear searching in small mode so it is never a good
idea to use SmallSize/N bigger than 32.

llvm-svn: 259283
diff --git a/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp b/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
index 2a6c853..c71163c 100644
--- a/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
@@ -321,7 +321,7 @@
 
   // Add all nodes in depth first order.
   SmallVector<SDNode*, 64> Worklist;
-  SmallPtrSet<SDNode*, 64> Visited;
+  SmallPtrSet<SDNode*, 32> Visited;
   Worklist.push_back(DAG->getRoot().getNode());
   Visited.insert(DAG->getRoot().getNode());