Index: lib/Driver/Tools.cpp
===================================================================
--- lib/Driver/Tools.cpp
+++ lib/Driver/Tools.cpp
@@ -1923,6 +1923,10 @@
     else
       CmdArgs.push_back("-plugin-opt=-debugger-tune=gdb");
   }
+  for (const Arg *A : Args.filtered(options::OPT_mllvm)) {
+    CmdArgs.push_back(Args.MakeArgString("-plugin-opt="
+                                         + StringRef(A->getValue(0))));
+  }
 }
 
 /// This is a helper function for validating the optional refinement step