Add an include of SmallSet.h.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@55793 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp
index 8a114f7..41d3cc1 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp
@@ -14,6 +14,7 @@
 #define DEBUG_TYPE "isel"
 #include "SelectionDAGBuild.h"
 #include "llvm/ADT/BitVector.h"
+#include "llvm/ADT/SmallSet.h"
 #include "llvm/Analysis/AliasAnalysis.h"
 #include "llvm/Constants.h"
 #include "llvm/CallingConv.h"