Nested functions and tail-call optimization

[Ian Lance Taylor]

On Mon, Aug 20, 2012 at 2:25 AM, Ludovic Courtès <ludo@gnu.org> wrote:
>
> Consider this function:
>
>   static tree filter (bool (*pred) (const_tree), tree);
>
>   static tree
>   list_remove (bool (*pred) (const_tree), tree t)
>   {
>     bool opposite (const_tree t)
>     {
>       return !pred (t);
>     }
>
>     return filter (opposite, t);
>   }
>
> Here, the call to ‘filter’ is likely subject to tail-call optimization.
> Is there any guarantee that ‘opposite’ is still reachable when ‘filter’
> is called?

It would clearly be a bug for GCC to do a sibling call from
list_remove to filter.

I don't know whether GCC has that bug or not.  If it does, please report it.

Ian