Revert: * dwarf2out.c (gen_formal_parameter_die): Remove obsolete hunk.

	Check ultimate_origin before setting reusing_die.

From-SVN: r251941

gcc/ChangeLog

-2017-09-09  Richard Biener  <rguenther@suse.de>
-	    Jason Merrill  <jason@redhat.com>
-
-	* dwarf2out.c (gen_formal_parameter_die): Remove obsolete hunk.
-	Check ultimate_origin before setting reusing_die.
-
 2017-09-08  Jason Merrill  <jason@redhat.com>
 
 	PR c++/70029 - ICE with ref-qualifier and -flto

gcc/dwarf2out.c

@@ -21285,15 +21285,30 @@ gen_formal_parameter_die (tree node, tree origin, bool emit_name_p,
 			  dw_die_ref context_die)
 {
   tree node_or_origin = node ? node : origin;
+  tree ultimate_origin;
   dw_die_ref parm_die = NULL;
   
   if (DECL_P (node_or_origin))
     {
       parm_die = lookup_decl_die (node);
 
-      tree ultimate_origin = decl_ultimate_origin (node_or_origin);
-      if (node || ultimate_origin)
-	origin = ultimate_origin;
+      /* If the contexts differ, we may not be talking about the same
+	 thing.
+	 ???  When in LTO the DIE parent is the "abstract" copy and the
+	 context_die is the specification "copy".  But this whole block
+	 should eventually be no longer needed.  */
+      if (parm_die && parm_die->die_parent != context_die && !in_lto_p)
+	{
+	  if (!DECL_ABSTRACT_P (node))
+	    {
+	      /* This can happen when creating an inlined instance, in
+		 which case we need to create a new DIE that will get
+		 annotated with DW_AT_abstract_origin.  */
+	      parm_die = NULL;
+	    }
+	  else
+	    gcc_unreachable ();
+	}
 
       if (parm_die && parm_die->die_parent == NULL)
 	{
@@ -21328,6 +21343,10 @@ gen_formal_parameter_die (tree node, tree origin, bool emit_name_p,
   switch (TREE_CODE_CLASS (TREE_CODE (node_or_origin)))
     {
     case tcc_declaration:
+      ultimate_origin = decl_ultimate_origin (node_or_origin);
+      if (node || ultimate_origin)
+	origin = ultimate_origin;
+
       if (reusing_die)
 	goto add_location;