diff -r d96f52012aaa -r 740e263c80c6 src/cpu/x86/vm/vtableStubs_x86_64.cpp
--- a/src/cpu/x86/vm/vtableStubs_x86_64.cpp	Wed Aug 14 15:12:00 2013 -0700
+++ b/src/cpu/x86/vm/vtableStubs_x86_64.cpp	Thu Aug 15 20:04:10 2013 -0400
@@ -211,11 +211,11 @@
   if (is_vtable_stub) {
     // Vtable stub size
     return (DebugVtables ? 512 : 24) + (CountCompiledCalls ? 13 : 0) +
-           (UseCompressedKlassPointers ? 16 : 0);  // 1 leaq can be 3 bytes + 1 long
+           (UseCompressedKlassPointers ?  MacroAssembler::instr_size_for_decode_klass_not_null() : 0);
   } else {
     // Itable stub size
     return (DebugVtables ? 512 : 74) + (CountCompiledCalls ? 13 : 0) +
-           (UseCompressedKlassPointers ? 32 : 0);  // 2 leaqs
+           (UseCompressedKlassPointers ?  MacroAssembler::instr_size_for_decode_klass_not_null() : 0);
   }
   // In order to tune these parameters, run the JVM with VM options
   // +PrintMiscellaneous and +WizardMode to see information about