--- old/src/share/vm/opto/compile.cpp	2011-12-07 12:03:23.000000000 +0100
+++ new/src/share/vm/opto/compile.cpp	2011-12-07 12:03:23.000000000 +0100
@@ -1307,10 +1307,12 @@
     // these 2 disparate memories into the same alias class.  Since the
     // primary supertype array is read-only, there's no chance of confusion
     // where we bypass an array load and an array store.
-    uint off2 = offset - Klass::primary_supers_offset_in_bytes();
+    // Bug: the "- sizeof(klassOopDesc)" bug was exposed by moving
+    //      sizeof(klassOopDesc) into the *_offset_in_bytes() functions.
+    uint off2 = offset - (Klass::primary_supers_offset_in_bytes() - sizeof(klassOopDesc));
     if( offset == Type::OffsetBot ||
         off2 < Klass::primary_super_limit()*wordSize ) {
-      offset = sizeof(oopDesc) +Klass::secondary_super_cache_offset_in_bytes();
+      offset = Klass::secondary_super_cache_offset_in_bytes();
       tj = tk = TypeKlassPtr::make( TypePtr::NotNull, tk->klass(), offset );
     }
   }
@@ -1489,13 +1491,13 @@
         alias_type(idx)->set_rewritable(false);
     }
     if (flat->isa_klassptr()) {
-      if (flat->offset() == Klass::super_check_offset_offset_in_bytes() + (int)sizeof(oopDesc))
+      if (flat->offset() == Klass::super_check_offset_offset_in_bytes())
         alias_type(idx)->set_rewritable(false);
-      if (flat->offset() == Klass::modifier_flags_offset_in_bytes() + (int)sizeof(oopDesc))
+      if (flat->offset() == Klass::modifier_flags_offset_in_bytes())
         alias_type(idx)->set_rewritable(false);
-      if (flat->offset() == Klass::access_flags_offset_in_bytes() + (int)sizeof(oopDesc))
+      if (flat->offset() == Klass::access_flags_offset_in_bytes())
         alias_type(idx)->set_rewritable(false);
-      if (flat->offset() == Klass::java_mirror_offset_in_bytes() + (int)sizeof(oopDesc))
+      if (flat->offset() == Klass::java_mirror_offset_in_bytes())
         alias_type(idx)->set_rewritable(false);
     }
     // %%% (We would like to finalize JavaThread::threadObj_offset(),