Index: cfe/trunk/lib/Driver/Tools.cpp
===================================================================
--- cfe/trunk/lib/Driver/Tools.cpp
+++ cfe/trunk/lib/Driver/Tools.cpp
@@ -919,11 +919,6 @@
     else
       CmdArgs.push_back("-aarch64-global-merge=true");
   }
-
-  if (Args.hasArg(options::OPT_ffixed_x18)) {
-    CmdArgs.push_back("-backend-option");
-    CmdArgs.push_back("-aarch64-reserve-x18");
-  }
 }
 
 // Get CPU and ABI names. They are not independent
@@ -1971,6 +1966,9 @@
     else
       Features.push_back("-crc");
   }
+
+  if (Args.hasArg(options::OPT_ffixed_x18))
+    Features.push_back("+reserve-x18");
 }
 
 static void getTargetFeatures(const Driver &D, const llvm::Triple &Triple,