diff --git a/llvm/include/llvm/CodeGen/GlobalISel/GISelWorkList.h b/llvm/include/llvm/CodeGen/GlobalISel/GISelWorkList.h
index 227b0a2486e0..626a66620fa1 100644
--- a/llvm/include/llvm/CodeGen/GlobalISel/GISelWorkList.h
+++ b/llvm/include/llvm/CodeGen/GlobalISel/GISelWorkList.h
@@ -33,7 +33,7 @@ class GISelWorkList {
   DenseMap<MachineInstr *, unsigned> WorklistMap;
 
 public:
-  GISelWorkList() {}
+  GISelWorkList() : WorklistMap(N) {}
 
   bool empty() const { return WorklistMap.empty(); }