On Wed, 9 Jun 2021 23:39:45 +0200
Harald Anlauf via Gcc-patches <gcc-patches@gcc.gnu.org> wrote:
> diff --git a/gcc/fortran/simplify.c b/gcc/fortran/simplify.c
> index c27b47aa98f..016ec259518 100644
> --- a/gcc/fortran/simplify.c
> +++ b/gcc/fortran/simplify.c
> @@ -4512,6 +4512,60 @@ gfc_simplify_leadz (gfc_expr *e)
> }
>
>
> +/* Check for constant length of a substring. */
> +
> +static bool
> +substring_has_constant_len (gfc_expr *e)
> +{
> + ptrdiff_t istart, iend;
> + size_t length;
> + bool equal_length = false;
> +
> + if (e->ts.type != BT_CHARACTER
> + || !(e->ref && e->ref->type == REF_SUBSTRING)
iff we ever can get here with e->ref == NULL then the below will not
work too well. If so then maybe
if (e->ts.type != BT_CHARACTER
|| ! e->ref
|| e->ref->type != REF_SUBSTRING
?
> + || !e->ref->u.ss.start
> + || e->ref->u.ss.start->expr_type != EXPR_CONSTANT
> + || !e->ref->u.ss.end
> + || e->ref->u.ss.end->expr_type != EXPR_CONSTANT
> + || !e->ref->u.ss.length
> + || !e->ref->u.ss.length->length
> + || e->ref->u.ss.length->length->expr_type != EXPR_CONSTANT)
> + return false;
> +
> + /* Basic checks on substring starting and ending indices. */
> + if (!gfc_resolve_substring (e->ref, &equal_length))
> + return false;
> +
> + istart = gfc_mpz_get_hwi (e->ref->u.ss.start->value.integer);
> + iend = gfc_mpz_get_hwi (e->ref->u.ss.end->value.integer);
> + length = gfc_mpz_get_hwi (e->ref->u.ss.length->length->value.integer);
> +
> + if (istart <= iend)
> + {
> + if (istart < 1)
> + {
> + gfc_error ("Substring start index (%ld) at %L below 1",
> + (long) istart, &e->ref->u.ss.start->where);
> + return false;
> + }
> + if (iend > (ssize_t) length)
> + {
> + gfc_error ("Substring end index (%ld) at %L exceeds string "
> + "length", (long) iend, &e->ref->u.ss.end->where);
> + return false;
> + }
> + length = iend - istart + 1;
> + }
> + else
> + length = 0;
> +
> + /* Fix substring length. */
> + e->value.character.length = length;
> +
> + return true;
> +}
> +
> +
> gfc_expr *
> gfc_simplify_len (gfc_expr *e, gfc_expr *kind)
> {
> @@ -4547,6 +4601,13 @@ gfc_simplify_len (gfc_expr *e, gfc_expr *kind)
> of the unlimited polymorphic entity. To get the _len component the
> last
> _data ref needs to be stripped and a ref to the _len component added.
> */
> return gfc_get_len_component (e->symtree->n.sym->assoc->target, k);
> + else if (substring_has_constant_len (e))
> + {
> + result = gfc_get_constant_expr (BT_INTEGER, k, &e->where);
> + mpz_set_si (result->value.integer,
> + e->value.character.length);
I think the mpz_set_si args above fit on one line.
btw.. there's a commentary typo in add_init_expr_to_sym():
s/skeep/skip/
thanks,
> + return range_check (result, "LEN");
> + }
> else
> return NULL;
> }
> diff --git a/gcc/testsuite/gfortran.dg/pr100950.f90
> b/gcc/testsuite/gfortran.dg/pr100950.f90
> new file mode 100644
> index 00000000000..f06db45b0b4
> --- /dev/null
> +++ b/gcc/testsuite/gfortran.dg/pr100950.f90
> @@ -0,0 +1,18 @@
> +! { dg-do run }
> +! PR fortran/100950 - ICE in output_constructor_regular_field, at
> varasm.c:5514
> +
> +program p
> + character(8), parameter :: u = "123"
> + character(8) :: x = "", s
> + character(2) :: w(2) = [character(len(x(3:4))) :: 'a','b' ]
> + character(*), parameter :: y(*) = [character(len(u(3:4))) :: 'a','b' ]
> + character(*), parameter :: z(*) = [character(len(x(3:4))) :: 'a','b' ]
> + if (len (y) /= 2) stop 1
> + if (len (z) /= 2) stop 2
> + if (any (w /= y)) stop 3
> + if (len ([character(len(u(3:4))) :: 'a','b' ]) /= 2) stop 4
> + if (len ([character(len(x(3:4))) :: 'a','b' ]) /= 2) stop 5
> + if (any ([character(len(x(3:4))) :: 'a','b' ] /= y)) stop 6
> + write(s,*) [character(len(x(3:4))) :: 'a','b' ]
> + if (s /= " a b ") stop 7
> +end
