More explicit keywords.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40757 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/VirtRegMap.h b/lib/CodeGen/VirtRegMap.h
index b7cbe51c..e5d4b22 100644
--- a/lib/CodeGen/VirtRegMap.h
+++ b/lib/CodeGen/VirtRegMap.h
@@ -75,7 +75,7 @@
     void operator=(const VirtRegMap&); // DO NOT IMPLEMENT
 
   public:
-    VirtRegMap(MachineFunction &mf);
+    explicit VirtRegMap(MachineFunction &mf);
 
     void grow();