--- old/src/share/vm/c1/c1_Instruction.hpp	2012-02-15 17:38:38.499158589 -0500
+++ new/src/share/vm/c1/c1_Instruction.hpp	2012-02-15 17:38:36.725502984 -0500
@@ -107,6 +107,7 @@
 class   ProfileCall;
 class   ProfileInvoke;
 class   RuntimeCall;
+class   MemBar;
 
 // A Value is a reference to the instruction creating the value
 typedef Instruction* Value;
@@ -204,6 +205,7 @@
   virtual void do_ProfileCall    (ProfileCall*     x) = 0;
   virtual void do_ProfileInvoke  (ProfileInvoke*   x) = 0;
   virtual void do_RuntimeCall    (RuntimeCall*     x) = 0;
+  virtual void do_MemBar         (MemBar*          x) = 0;
 };
 
 
@@ -2351,6 +2353,23 @@
   virtual void state_values_do(ValueVisitor*);
 };
 
+LEAF(MemBar, Instruction)
+ private:
+  LIR_Code _code; 
+
+ public:
+  MemBar(LIR_Code code)
+    : Instruction(voidType)
+    , _code(code)
+  {
+    pin();
+  }
+
+  LIR_Code code()           { return _code; } 
+
+  virtual void input_values_do(ValueVisitor*)   {}
+};
+
 class BlockPair: public CompilationResourceObj {
  private:
   BlockBegin* _from;