[Bug fortran/93365] ICE in match_data_constant, at fortran/decl.c:426

[sgk at troutmask dot apl.washington.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93365

--- Comment #6 from Steve Kargl <sgk at troutmask dot apl.washington.edu> ---
On Fri, Jan 24, 2020 at 12:36:45PM +0000, markeggleston at gcc dot gnu.org
wrote:
> gfc_simplify_expr calls simplify_parameter_variable which for zero size
> arrays it creates a new gfc_expr structure with the expr_type set to EXPR_ARRAY
> and replaces primary. When primary is replaced its chain of ref structures is
> deleted so tmp->u.i is invalid causing the ICE the following lines are never
> reached:

The lines are reached in my debugging sessions. :-)
I bootstrap with --enable-checking, which might 
prevent the ICE issue.

> > then enters the switch statement and get to lines 2384-2385
> > 
> >        primary->ts.type = BT_INTEGER;
> >        primary->ts.kind = gfc_default_integer_kind;
> > 
> > This just resets a part of primary, but it does not fix up
> > it up correctly.  Likely, need to check for zero size
> > arrays do extra work.
> 
> I have modified gfc_simplify_expr:

I'm beginning to think that calling gfc_simplify_expr may
not be correct, here.  But, don't have time to investigate
more.