diff --git a/clang/lib/CodeGen/CodeGenModule.h b/clang/lib/CodeGen/CodeGenModule.h
--- a/clang/lib/CodeGen/CodeGenModule.h
+++ b/clang/lib/CodeGen/CodeGenModule.h
@@ -335,7 +335,7 @@
   /// for emission and therefore should only be output if they are actually
   /// used. If a decl is in this, then it is known to have not been referenced
   /// yet.
-  std::map<StringRef, GlobalDecl> DeferredDecls;
+  llvm::DenseMap<StringRef, GlobalDecl> DeferredDecls;
 
   /// This is a list of deferred decls which we have seen that *are* actually
   /// referenced. These get code generated when the module is done.