--- old/src/hotspot/share/opto/callGenerator.cpp	2018-10-10 16:48:19.854883956 +0200
+++ new/src/hotspot/share/opto/callGenerator.cpp	2018-10-10 16:48:19.494703961 +0200
@@ -927,7 +927,11 @@
   }
   if (sig_type->is_valuetypeptr() && !arg->is_ValueType()) {
     kit.inc_sp(nargs); // restore arguments
-    arg = ValueTypeNode::make_from_oop(&kit, arg, t->as_value_klass(), /* buffer_check */ false, /* null2default */ false);
+    if (t->as_value_klass()->is_scalarizable()) {
+      arg = ValueTypeNode::make_from_oop(&kit, arg, t->as_value_klass(), /* buffer_check */ false, /* null2default */ false);
+    } else {
+      arg = kit.filter_null(arg);
+    }
     kit.dec_sp(nargs);
     kit.set_argument(arg_nb, arg);
   }