2011-04-03  Alan Modra  <amodra@gmail.com>

	* dwarf2out.c (mem_loc_descriptor): Recurse on LO_SUM.

Index: gcc/dwarf2out.c
===================================================================
--- gcc/dwarf2out.c	(revision 171904)
+++ gcc/dwarf2out.c	(revision 171905)
@@ -13706,9 +13706,7 @@ mem_loc_descriptor (rtx rtl, enum machin
       break;
 
     case LO_SUM:
-	 rtl = XEXP (rtl, 1);
-
-      /* ... fall through ...  */
+      return mem_loc_descriptor (XEXP (rtl, 1), mode, initialized);
 
     case LABEL_REF:
       /* Some ports can transform a symbol ref into a label ref, because