Question about GTY machinery (cgraph_edge)

[Geoffrey Keating]

Richard Guenther <rguenth@tat.physik.uni-tuebingen.de> writes:

> Hi!
> 
> struct cgraph_edge is currently member of two lists, i.e.
> it contains two "next" pointers, but is annotated like
> 
> struct cgraph_edge GTY((chain_next ("%h.next_caller")))
> {
>   struct cgraph_node *caller;
>   struct cgraph_node *callee;
>   struct cgraph_edge *next_caller;
>   struct cgraph_edge *next_callee;
>   tree call_expr;
>   PTR GTY ((skip (""))) aux;
>   /* When NULL, inline this call.  When non-NULL, points to the
> explanation
>      why function was not inlined.  */
>   const char *inline_failed;
> };
> 
> Is it possible and beneficial to have both next pointers
> annotated with chain_next?

No, it's not possible.  I doubt it's beneficial, either.