diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp
index 6fc7373..3108477 100644
--- a/lib/Frontend/CompilerInvocation.cpp
+++ b/lib/Frontend/CompilerInvocation.cpp
@@ -202,6 +202,10 @@
     Res.push_back("-fobjc-dispatch-method=non-legacy");
     break;
   }
+  if (Opts.NumRegisterParameters) {
+    Res.push_back("-mregparm");
+    Res.push_back(llvm::utostr(Opts.NumRegisterParameters));
+  }
   if (Opts.RelaxAll)
     Res.push_back("-mrelax-all");
   if (Opts.SoftFloat)
@@ -928,6 +932,7 @@
   Opts.NoInfsFPMath = Opts.NoNaNsFPMath = Args.hasArg(OPT_cl_finite_math_only)||
                                           Args.hasArg(OPT_cl_fast_relaxed_math);
   Opts.NoZeroInitializedInBSS = Args.hasArg(OPT_mno_zero_initialized_in_bss);
+  Opts.NumRegisterParameters = Args.getLastArgIntValue(OPT_mregparm, 0, Diags);
   Opts.RelaxAll = Args.hasArg(OPT_mrelax_all);
   Opts.OmitLeafFramePointer = Args.hasArg(OPT_momit_leaf_frame_pointer);
   Opts.SoftFloat = Args.hasArg(OPT_msoft_float);