[PATCH] Improve PR45089

[Richard Guenther]

As discussed this makes us not ICE for PR45089 when checking is not
enabled and ICE in a more useful place if it is.

Bootstrapped and tested on x86_64-unknown-linux-gnu, applied.

Richard.

2010-11-18  Richard Guenther  <rguenther@suse.de>

	PR lto/45089
	* dwarf2out.c (add_AT_die_ref): Work around LTO losing types
	when checking is not enabled.

Index: gcc/dwarf2out.c
===================================================================
*** gcc/dwarf2out.c	(revision 166900)
--- gcc/dwarf2out.c	(working copy)
*************** add_AT_die_ref (dw_die_ref die, enum dwa
*** 7362,7367 ****
--- 7362,7376 ----
  {
    dw_attr_node attr;
  
+ #ifdef ENABLE_CHECKING
+   gcc_assert (targ_die != NULL);
+ #else
+   /* With LTO we can end up trying to reference something we didn't create
+      a DIE for.  Avoid crashing later on a NULL referenced DIE.  */
+   if (targ_die == NULL)
+     return;
+ #endif
+ 
    attr.dw_attr = attr_kind;
    attr.dw_attr_val.val_class = dw_val_class_die_ref;
    attr.dw_attr_val.v.val_die_ref.die = targ_die;