diff -r de91a2f25c7e -r 2d127394260e src/share/vm/gc_implementation/parallelScavenge/psParallelCompact.hpp
--- a/src/share/vm/gc_implementation/parallelScavenge/psParallelCompact.hpp	Thu May 27 09:54:07 2010 -0700
+++ b/src/share/vm/gc_implementation/parallelScavenge/psParallelCompact.hpp	Thu May 27 18:01:56 2010 -0700
@@ -1414,6 +1414,8 @@
 {
   assert(old_addr >= new_addr || space_id(old_addr) != space_id(new_addr),
          "must move left or to a different space");
+  assert(is_object_aligned((intptr_t)old_addr) && is_object_aligned((intptr_t)new_addr),
+         "checking alignment");
 }
 #endif // ASSERT