re PR target/53682 (ICE in cselib_lookup (SEGV) on i586-linux-gnu)

PR debug/53682
* cselib.c (promote_debug_loc): Don't crash on NULL argument.

From-SVN: r188866

gcc/ChangeLog

+2012-06-21  Alexandre Oliva  <aoliva@redhat.com>
+
+	PR debug/53682
+	* cselib.c (promote_debug_loc): Don't crash on NULL argument.
+
 2012-06-21  Meador Inge  <meadori@codesourcery.com>
 
 	PR c/53702

gcc/cselib.c

@@ -322,7 +322,7 @@ new_elt_loc_list (cselib_val *val, rtx loc)
 static inline void
 promote_debug_loc (struct elt_loc_list *l)
 {
-  if (l->setting_insn && DEBUG_INSN_P (l->setting_insn)
+  if (l && l->setting_insn && DEBUG_INSN_P (l->setting_insn)
       && (!cselib_current_insn || !DEBUG_INSN_P (cselib_current_insn)))
     {
       n_debug_values--;