[committed]: vms/ia64: avoid a crash if -mdebug-main is used without -g

[Tristan Gingold]

Hi,

this simple patch adds a guard to avoid a crash.  As -mdebug-main directly 
calls dwarf2out, debug_info_level should be checked before.

Committed on trunk.

Tristan.

2011-04-21  Tristan Gingold  <ging...@adacore.com>

        * config/ia64/ia64.c (ia64_start_function): Add a guard.

--- gcc/config/ia64/ia64.c      (revision 172821)
+++ gcc/config/ia64/ia64.c      (working copy)
@@ -3542,6 +3542,7 @@
 {
 #if VMS_DEBUGGING_INFO
   if (vms_debug_main
+      && debug_info_level > DINFO_LEVEL_NONE
       && strncmp (vms_debug_main, fnname, strlen (vms_debug_main)) == 0)
     {
       targetm.asm_out.globalize_label (asm_out_file, VMS_DEBUG_MAIN_POINTER);