On Tue, Feb 12, 2013 at 09:58:38AM -0600, Aldy Hernandez wrote:
> OK for trunk?
I'd still prefer Richard to chime in, I'm really not familiar enough
with MIPS switchable target stuff.
> +/* Recompute the optabs. If they have changed, save the new set of
> + optabs in the optimization node OPTNODE. */
> +
> +void
> +save_optabs_if_changed (tree optnode)
> +{
> + struct target_optabs *save_target_optabs = this_target_optabs;
> + struct target_optabs *tmp_target_optabs = XCNEW (struct target_optabs);
> +
> + /* Generate a new set of optabs into tmp_target_optabs. */
> + this_target_optabs = tmp_target_optabs;
> + init_all_optabs ();
> + this_target_optabs = save_target_optabs;
> +
> + /* If the optabs changed, record it in the node. */
> + if (memcmp (tmp_target_optabs, &default_target_optabs,
> + sizeof (struct target_optabs)))
> + {
> + /* ?? An existing entry in TREE_OPTIMIZATION_OPTABS indicates
> + multiple ((optimize)) attributes for the same function. Is
> + this even valid? For now, just clobber the existing entry
> + with the new optabs. */
> + if (TREE_OPTIMIZATION_OPTABS (optnode))
> + XDELETE (TREE_OPTIMIZATION_OPTABS (optnode));
I wonder if this necessarily won't mean that if TREE_OPTIMIZATION_OPTABS
is non-NULL, then memcmp (tmp_target_optabs, TREE_OPTIMIZATION_OPTABS
(optnode), sizeof (*tmp_target_optabs)) == 0. Because, optimization nodes
are only shared if they contain the same set of all options.
Multiple optimize attributes seems to be valid, see what
handle_optimize_attribute says on them, but they together either create
a fresh optimization node which certainly won't have
TREE_OPTIMIZATION_OPTABS set, or they return one older, but that should be
already initialized to the same thing.
So perhaps start the function with
if (TREE_OPTIMIZATION_OPTABS (optnode))
return;
? I.e., if you have multiple functions with the same optimization node,
there is no need to do init_all_optabs again and again.
Perhaps we want to have a flag whether TREE_OPTIMIZATION_OPTABS has been
computed already, and don't call save_optabs_if_changed if already set,
or add some magic value for TREE_OPTIMIZATION_OPTABS, where e.g. NULL
would mean not computed yet, the special magic value would mean the default
and other values the special optabs? Perhaps the magic value could be
just &default_target_optabs...
Jakub
