diff -r d79f8393df2b -r 701a83c86f28 src/share/vm/c1/c1_InstructionPrinter.cpp
--- a/src/share/vm/c1/c1_InstructionPrinter.cpp	Wed Feb 22 14:00:34 2012 -0500
+++ b/src/share/vm/c1/c1_InstructionPrinter.cpp	Tue Feb 21 13:14:55 2012 -0500
@@ -855,4 +855,20 @@
   output()->put(')');
 }
 
+void InstructionPrinter::do_MemBar(MemBar* x) {
+  if (os::is_MP()) {
+    LIR_Code code = x->code();
+    switch (code) {
+      case lir_membar_acquire   : output()->print("membar_acquire"); break;
+      case lir_membar_release   : output()->print("membar_release"); break;
+      case lir_membar           : output()->print("membar"); break;
+      case lir_membar_loadload  : output()->print("membar_loadload"); break;
+      case lir_membar_storestore: output()->print("membar_storestore"); break;
+      case lir_membar_loadstore : output()->print("membar_loadstore"); break;
+      case lir_membar_storeload : output()->print("membar_storeload"); break;
+      default                   : ShouldNotReachHere(); break;
+    }
+  }
+}
+
 #endif // PRODUCT