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-rw-r--r--gcc/fortran/resolve.c25
1 files changed, 20 insertions, 5 deletions
diff --git a/gcc/fortran/resolve.c b/gcc/fortran/resolve.c
index 92d27fc..3a8f402 100644
--- a/gcc/fortran/resolve.c
+++ b/gcc/fortran/resolve.c
@@ -4965,6 +4965,7 @@ gfc_resolve_substring_charlen (gfc_expr *e)
gfc_ref *char_ref;
gfc_expr *start, *end;
gfc_typespec *ts = NULL;
+ mpz_t diff;
for (char_ref = e->ref; char_ref; char_ref = char_ref->next)
{
@@ -5016,11 +5017,25 @@ gfc_resolve_substring_charlen (gfc_expr *e)
return;
}
- /* Length = (end - start + 1). */
- e->ts.u.cl->length = gfc_subtract (end, start);
- e->ts.u.cl->length = gfc_add (e->ts.u.cl->length,
- gfc_get_int_expr (gfc_charlen_int_kind,
- NULL, 1));
+ /* Length = (end - start + 1).
+ Check first whether it has a constant length. */
+ if (gfc_dep_difference (end, start, &diff))
+ {
+ gfc_expr *len = gfc_get_constant_expr (BT_INTEGER, gfc_charlen_int_kind,
+ &e->where);
+
+ mpz_add_ui (len->value.integer, diff, 1);
+ mpz_clear (diff);
+ e->ts.u.cl->length = len;
+ /* The check for length < 0 is handled below */
+ }
+ else
+ {
+ e->ts.u.cl->length = gfc_subtract (end, start);
+ e->ts.u.cl->length = gfc_add (e->ts.u.cl->length,
+ gfc_get_int_expr (gfc_charlen_int_kind,
+ NULL, 1));
+ }
/* F2008, 6.4.1: Both the starting point and the ending point shall
be within the range 1, 2, ..., n unless the starting point exceeds