Index: include/clang/Tooling/CompilationDatabase.h
===================================================================
--- include/clang/Tooling/CompilationDatabase.h
+++ include/clang/Tooling/CompilationDatabase.h
@@ -59,6 +59,11 @@
 
   /// The output file associated with the command.
   std::string Output;
+
+  bool operator==(const CompileCommand &RHS) const {
+    return Directory == RHS.Directory && Filename == RHS.Filename &&
+           CommandLine == RHS.CommandLine && Output == RHS.Output;
+  }
 };
 
 /// Interface for compilation databases.