[patch] update comments on *_ultimate_origin

[Aldy Hernandez]

output_inline_function was removed in tree-ssa times, no sense 
referencing it a decade later.

I still see DECL_ABSTRACT_ORIGIN pointing to itself in some instances, 
though I haven't tracked down where, so I assume we still need the 
functionality, just not the comment :).

OK for mainline?

Aldy
commit d51576de0a8450634ff7622e4688fd02fc8fcee9
Author: Aldy Hernandez <al...@redhat.com>
Date:   Thu Sep 18 10:35:30 2014 -0600

        * dwarf2out.c (decl_ultimate_origin): Update comment.
        * tree.c (block_ultimate_origin): Same.

diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c
index 23a80d8..c65c756 100644
--- a/gcc/dwarf2out.c
+++ b/gcc/dwarf2out.c
@@ -3676,8 +3676,7 @@ decl_ultimate_origin (const_tree decl)
   if (!CODE_CONTAINS_STRUCT (TREE_CODE (decl), TS_DECL_COMMON))
     return NULL_TREE;
 
-  /* output_inline_function sets DECL_ABSTRACT_ORIGIN for all the
-     nodes in the function to point to themselves; ignore that if
+  /* DECL_ABSTRACT_ORIGIN can point to itself; ignore that if
      we're trying to output the abstract instance of this function.  */
   if (DECL_ABSTRACT (decl) && DECL_ABSTRACT_ORIGIN (decl) == decl)
     return NULL_TREE;
diff --git a/gcc/tree.c b/gcc/tree.c
index d1d67ef..fc544de 100644
--- a/gcc/tree.c
+++ b/gcc/tree.c
@@ -11554,8 +11554,7 @@ block_ultimate_origin (const_tree block)
 {
   tree immediate_origin = BLOCK_ABSTRACT_ORIGIN (block);
 
-  /* output_inline_function sets BLOCK_ABSTRACT_ORIGIN for all the
-     nodes in the function to point to themselves; ignore that if
+  /* BLOCK_ABSTRACT_ORIGIN can point to itself; ignore that if
      we're trying to output the abstract instance of this function.  */
   if (BLOCK_ABSTRACT (block) && immediate_origin == block)
     return NULL_TREE;