On Tue, May 02, 2017 at 02:50:16PM +0200, Richard Biener wrote:
> > If array_at_struct_end_p is wrong, it should be fixed ;)
>
> Indeed. It was originally meant to say false if you can trust
> TYPE_DOMAIN of the array but now it says false if there's some means
> to constrain the array size (the DECL_P path and now your STRING_CST
> one). But all callers afterwards just look at TYPE_DOMAIN ...
So shall we verify that TYPE_DOMAIN is consistent with the object size
in that case inside of array_at_struct_end_p?
> > > I'd restructure the patch quite different, using for_each_index on the
> > > ref gather an array of index pointers (bail out on sth unhandled).
> > > Then I'd see if I have interesting ranges for them, if not, bail out.
> > > Also compute the size product of all ranges and test that against
> > > PARAM_MAX_VRP_CONSTANT_ARRAY_LOADS. Then store the minimum range
> > > value in the index places (temporarily) and use get_base_ref_and_extent to
> > > get at the constant "starting" offset. From there iterate using
> > > the remembered indices (remember the ref tree as well via for_each_index),
> > > directly adjusting the constant offset so you can feed
> > > fold_ctor_reference the constant offsets of all elements that need to
> > > be considered. As optimization fold_ctor_reference would know how
> > > to start from the "last" offset (much refactoring would need to be
> > > done here given nested ctors and multiple indices I guess).
> >
> > But for this, don't you want to take it over?
>
> I can try. Is there a PR for this?
Ok, filed PR80603, it is now all yours.
> > I agree that the current implementation is not very efficient and that is
> > why it is also limited to that small number of iterations.
> > As many cases just aren't able to use the valueize callback, handling
> > arbitrary numbers of non-constant indexes would be harder.
>
> Sure. I'd have expected you simply handle ARRAY_REF of a VAR_DECL
> and nothing else ;)
That would be too simple and boring ;)
Jakub
