--- a/src/share/vm/runtime/arguments.cpp	Wed Jun 19 10:45:56 2013 +0200
+++ b/src/share/vm/runtime/arguments.cpp	Wed Jun 19 15:37:32 2013 +0200
@@ -2219,6 +2219,38 @@
     FLAG_SET_CMDLINE(bool, UseCompressedOops, false);
   }
 
+  if (UseCompressedKlassPointers) {
+    if (IgnoreUnrecognizedVMOptions) {
+      warning("UseCompressedKlassPointers is disabled, because it is not supported by Graal");
+      FLAG_SET_CMDLINE(bool, UseCompressedKlassPointers, false);
+    } else {
+      jio_fprintf(defaultStream::error_stream(),
+                    "UseCompressedKlassPointers are not supported in Graal at the moment\n");
+      status = false;
+    }
+  } else {
+    // This prevents the flag being set to true by set_ergonomics_flags()
+    FLAG_SET_CMDLINE(bool, UseCompressedKlassPointers, false);
+  }
+  if (UseG1GC) {
+      if (IgnoreUnrecognizedVMOptions) {
+        warning("UseG1GC is still experimental in Graal, use SerialGC instead ");
+        FLAG_SET_CMDLINE(bool, UseG1GC, true);
+      } else {
+        warning("UseG1GC is still experimental in Graal, use SerialGC instead ");
+        status = true;
+      }
+    } else {
+      // This prevents the flag being set to true by set_ergonomics_flags()
+      FLAG_SET_CMDLINE(bool, UseG1GC, false);
+    }
+
+  if (!ScavengeRootsInCode) {
+      warning("forcing ScavengeRootsInCode non-zero because Graal is enabled");
+      ScavengeRootsInCode = 1;
+  }
+
+#endif
   return status;
 }