diff -r eacd97c88873 -r b109e761e927 src/share/vm/runtime/stackValue.hpp
--- a/src/share/vm/runtime/stackValue.hpp	Fri Jun 05 10:25:39 2009 -0700
+++ b/src/share/vm/runtime/stackValue.hpp	Tue Jun 09 16:19:10 2009 -0700
@@ -34,9 +34,11 @@
     _i     = value;
   }
 
-  StackValue(Handle value) {
+  StackValue(Handle value, intptr_t scalar_replaced = 0) {
     _type    = T_OBJECT;
+    _i       = scalar_replaced;
     _o       = value;
+    assert(_i == 0 || _o.is_null(), "not null object should not be marked as scalar replaced");
   }
 
   StackValue() {
@@ -56,6 +58,11 @@
     return _o;
   }
 
+  bool obj_is_scalar_replaced() const {
+    assert(type() == T_OBJECT, "type check");
+    return _i != 0;
+  }
+
   void set_obj(Handle value) {
     assert(type() == T_OBJECT, "type check");
     _o = value;