diff options
Diffstat (limited to 'gcc/fortran/resolve.c')
| -rw-r--r-- | gcc/fortran/resolve.c | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/gcc/fortran/resolve.c b/gcc/fortran/resolve.c index 4378313..1fc540a 100644 --- a/gcc/fortran/resolve.c +++ b/gcc/fortran/resolve.c @@ -6546,6 +6546,29 @@ gfc_resolve_iterator (gfc_iterator *iter, bool real_ok, bool own_scope) &iter->step->where); } + if (iter->end->expr_type == EXPR_CONSTANT + && iter->end->ts.type == BT_INTEGER + && iter->step->expr_type == EXPR_CONSTANT + && iter->step->ts.type == BT_INTEGER + && (mpz_cmp_si (iter->step->value.integer, -1L) == 0 + || mpz_cmp_si (iter->step->value.integer, 1L) == 0)) + { + bool is_step_positive = mpz_cmp_ui (iter->step->value.integer, 1) == 0; + int k = gfc_validate_kind (BT_INTEGER, iter->end->ts.kind, false); + + if (is_step_positive + && mpz_cmp (iter->end->value.integer, gfc_integer_kinds[k].huge) == 0) + gfc_warning (OPT_Wundefined_do_loop, + "DO loop at %L is undefined as it overflows", + &iter->step->where); + else if (!is_step_positive + && mpz_cmp (iter->end->value.integer, + gfc_integer_kinds[k].min_int) == 0) + gfc_warning (OPT_Wundefined_do_loop, + "DO loop at %L is undefined as it underflows", + &iter->step->where); + } + return true; } |