re PR middle-end/50074 (gcc.dg/sibcall-6.c execution test on x86_64 with -fPIC)

        PR middle-end/50074
        * calls.c (mem_overlaps_already_clobbered_arg_p):
        Return false if no outgoing arguments have been stored so far.

From-SVN: r181738

gcc/ChangeLog

+2011-11-26  Joern Rennecke  <joern.rennecke@embecosm.com>
+
+	PR middle-end/50074
+	* calls.c (mem_overlaps_already_clobbered_arg_p):
+	Return false if no outgoing arguments have been stored so far.
+
 2011-11-25  Georg-Johann Lay  <avr@gjlay.de>
 
 	* config/avr/avr.c (print_operand): Support code = 'i' for CONST_INT.

gcc/calls.c

@@ -1668,6 +1668,8 @@ mem_overlaps_already_clobbered_arg_p (rtx addr, unsigned HOST_WIDE_INT size)
 {
   HOST_WIDE_INT i;
 
+  if (sbitmap_empty_p (stored_args_map))
+    return false;
   if (addr == crtl->args.internal_arg_pointer)
     i = 0;
   else if (GET_CODE (addr) == PLUS