Re: RFA: PATCH to gimple_canonical_types_compatible_p for middle-end/66214

[Jan Hubicka <hubicka at ucw dot cz>]

> On 11/25/2015 02:10 PM, Jan Hubicka wrote:
> >>The problem here is that we're trying to compare the TYPE_FIELDS of
> >>two variants of an incomplete type, which doesn't make sense; we
> >>shouldn't expect TYPE_FIELDS of an incomplete type to be meaningful.
> >>
> >>Tested x86_64-pc-linux-gnu.  OK for trunk?
> >
> >>commit c6f5cd55d0bbebc2fa46628ebb8fdec2a44abf3a
> >>Author: Jason Merrill <jason@redhat.com>
> >>Date:   Wed Nov 25 10:47:03 2015 -0500
> >>
> >>     	PR middle-end/66214
> >>
> >>     	* tree.c (gimple_canonical_types_compatible_p) [RECORD_TYPE]:
> >>     	Don't try to compare the fields of incomplete types.
> >
> >This makes sense to me.  I would still add a check that incomplete types have to
> >TYPE_FIELDS during LTO so we are sure that all types are either completed or
> >have no fields at all once the frontends are done.
> 
> Like this?
> 

> commit f264166c7358de8eb1c499e2c0a80f8f7cf2d100
> Author: Jason Merrill <jason@redhat.com>
> Date:   Wed Nov 25 17:05:47 2015 -0500
> 
>     assert
> 
> diff --git a/gcc/tree.c b/gcc/tree.c
> index e918e1b..0108e80 100644
> --- a/gcc/tree.c
> +++ b/gcc/tree.c
> @@ -13429,6 +13429,12 @@ gimple_canonical_types_compatible_p (const_tree t1, const_tree t2,
>  	if (!COMPLETE_TYPE_P (t1) && !COMPLETE_TYPE_P (t2))
>  	  return true;
>  
> +	/* In LTO, incomplete types should always have null TYPE_FIELDS.  */
> +	if (in_lto_p)
> +	  gcc_checking_assert
> +	    ((COMPLETE_TYPE_P (t1) || TYPE_FIELDS (t1) == NULL_TREE)
> +	     && (COMPLETE_TYPE_P (t2) || TYPE_FIELDS (t2) == NULL_TREE));

I think this more belongs to verify_type which is also called on variant types
(where we can also output friendly debug_tree message)

Looks good to me with that change.
Thanks a lot!  Any help with type verification issues is greatly appreachiated.
Honza