https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93365
markeggleston at gcc dot gnu.org changed:
What |Removed |Added
----------------------------------------------------------------------------
Assignee|unassigned at gcc dot gnu.org |markeggleston at gcc
dot gnu.org
--- Comment #5 from markeggleston at gcc dot gnu.org ---
(In reply to Steve Kargl from comment #4)
> On Thu, Jan 23, 2020 at 03:37:04PM +0000, markeggleston at gcc dot gnu.org
> wrote:
> >
> > If the parameter attribute is removed or a non zero sized array is used, the
> > ICE does not occur.
> >
> > The ICE occurs in gfc_match_varspec (primary.c) a temporary gfc_ref
> > structure
> > has been created and has the type REF_INQUIRY. If the primary expression has
> > been passed in is EXPR_CONSTANT the check is done. When the ICE occurs the
> > type
> > is EXPR_STRUCTURE, so the value of the REF_INQUIRY taken from u.i is used
> > for
> > the inquiry type instead of being 2 (INQUIRY_KIND) it is random
> > e.g.73176720.
> >
>
> Not quite, right. If you have
>
> complex, parameter :: a(1) = 0
> integer b
> data b/a%kind%
>
> then at line 2337 in primary.c
>
> gfc_simplify_expr (primary, 0);
>
> collapses primary to an EXPR_CONSTANT, and then things seem to work.
>
> If you have
>
> complex, parameter :: a(0) = 0
> integer b
> data b/a%kind%
>
> then "gfc_simplify_expr (primary, 0)" does not collapse primary
> to EXPR_CONSTANT as it seems gfc_simplify_expr does not handle
> zero size arrays (as there is nothing to simplify!). gfortran
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:
> 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:
--- a/gcc/fortran/expr.c
+++ b/gcc/fortran/expr.c
@@ -2069,8 +2069,13 @@ simplify_parameter_variable (gfc_expr *p, int type)
e->value.constructor = NULL;
e->shape = gfc_copy_shape (p->shape, p->rank);
e->where = p->where;
- gfc_replace_expr (p, e);
- return true;
+ e->ref = gfc_copy_ref (p->ref);
+ t = gfc_simplify_expr (e, type);
+ if (t && !e->ref)
+ gfc_replace_expr (p, e);
+ else
+ gfc_free_expr (e);
+ return t;
}
e = gfc_copy_expr (p->symtree->n.sym->value);
This results in primary being reduced to a EXPR_CONSTANT just like it is for
non-zero length arrays.
I've checked the 8 and 9 branches, 8 does not support this syntax and 9.2
behaves differently:
program p
real, parameter :: a(0) = 0.5
write(*,*) a%kind
end
compiles but the output is:
0.500000000
and
program p
real, parameter :: a(1) = 0.5
write(*,*) a%kind
end
fails to compile with an ICE. I'll investigate these further and ad either 1 or
2 new PRs.
I'm now getting failures for several test cases in gfortran.dg, more work to
do...
