diff -r a516debe2cee -r a3e2f723f2a5 src/share/vm/asm/codeBuffer.cpp
--- a/src/share/vm/asm/codeBuffer.cpp	Fri Oct 26 14:18:57 2012 -0700
+++ b/src/share/vm/asm/codeBuffer.cpp	Mon Oct 29 11:08:48 2012 -0700
@@ -758,7 +758,7 @@
     }
   }
 
-  if (dest->blob() == NULL) {
+  if (dest->blob() == NULL && dest_filled != NULL) {
     // Destination is a final resting place, not just another buffer.
     // Normalize uninitialized bytes in the final padding.
     Copy::fill_to_bytes(dest_filled, dest_end - dest_filled,