diff --git a/lib/CodeGen/MachineBlockPlacement.cpp b/lib/CodeGen/MachineBlockPlacement.cpp
index b725bfb49c8..7eec164f148 100644
--- a/lib/CodeGen/MachineBlockPlacement.cpp
+++ b/lib/CodeGen/MachineBlockPlacement.cpp
@@ -949,6 +949,7 @@ void MachineBlockPlacement::buildCFGChains(MachineFunction &F) {
   BlockChain &FunctionChain = *BlockToChain[&F.front()];
   buildChain(&F.front(), FunctionChain, BlockWorkList);
 
+  typedef SmallPtrSet<MachineBasicBlock *, 16> FunctionBlockSetType;
   DEBUG({
     // Crash at the end so we get all of the debugging output first.
     bool BadFunc = false;