Convert vector to smallvector: 4% speedup.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@29735 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/llvm/CodeGen/ScheduleDAG.h b/include/llvm/CodeGen/ScheduleDAG.h
index dbf5328..ed6ccd0 100644
--- a/include/llvm/CodeGen/ScheduleDAG.h
+++ b/include/llvm/CodeGen/ScheduleDAG.h
@@ -78,7 +78,7 @@
   /// a group of nodes flagged together.
   struct SUnit {
     SDNode *Node;                       // Representative node.
-    std::vector<SDNode*> FlaggedNodes;  // All nodes flagged to Node.
+    SmallVector<SDNode*,4> FlaggedNodes;// All nodes flagged to Node.
     
     // Preds/Succs - The SUnits before/after us in the graph.  The boolean value
     // is true if the edge is a token chain edge, false if it is a value edge.