(find_basic_blocks): Don't mark labels in nonlocal_label_list

that were deleted due to having no references.

From-SVN: r3310

gcc/flow.c

@@ -538,8 +538,11 @@ find_basic_blocks (f, nonlocal_label_list)
 	  {
 	    rtx x;
 	    for (x = nonlocal_label_list; x; x = XEXP (x, 1))
-	      mark_label_ref (gen_rtx (LABEL_REF, VOIDmode, XEXP (x, 0)),
-			      insn, 0);
+	      /* Don't try marking labels that
+		 were deleted as unreferenced.  */
+	      if (GET_CODE (XEXP (x, 0)) == CODE_LABEL)
+		mark_label_ref (gen_rtx (LABEL_REF, VOIDmode, XEXP (x, 0)),
+				insn, 0);
 	    /* ??? This could be made smarter:
 	       in some cases it's possible to tell that certain
 	       calls will not do a nonlocal goto.