https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77505
--- Comment #6 from Elizebeth Punnoose <elizebethp at gmail dot com> ---
Modified code with the warning message moved behind -fcheck=bounds.
Index: trans-array.c
===================================================================
--- trans-array.c (revision 241960)
+++ trans-array.c (working copy)
@@ -2226,6 +2226,8 @@
gfc_ss_info *ss_info;
gfc_expr *expr;
gfc_ss *s;
+ tree neg_len;
+ char *msg;
/* Save the old values for nested checking. */
old_first_len = first_len;
@@ -2271,6 +2273,27 @@
gfc_conv_expr_type (&length_se, expr->ts.u.cl->length,
gfc_charlen_type_node);
ss_info->string_length = length_se.expr;
+
+ /* Check if the character length is negative,
+ if so consider it as LEN=0. */
+ neg_len = fold_build2_loc (input_location, LT_EXPR,
+ boolean_type_node, ss_info->string_length,
+ build_int_cst (gfc_charlen_type_node, 0));
+ /* Print a warning if bounds checking is enabled. */
+ if (gfc_option.rtcheck & GFC_RTCHECK_BOUNDS)
+ {
+ msg = xasprintf ("Negative character length will be treated as
LEN=0");
+ gfc_trans_runtime_check (false, true, neg_len,
+ &length_se.pre, where, msg);
+ free(msg);
+ }
+ ss_info->string_length = fold_build3_loc (input_location,
+ COND_EXPR, gfc_charlen_type_node,
+ neg_len, gfc_index_zero_node,
+ ss_info->string_length);
+ ss_info->string_length = gfc_evaluate_now (ss_info->string_length,
+ &length_se.pre);
+
gfc_add_block_to_block (&outer_loop->pre, &length_se.pre);
gfc_add_block_to_block (&outer_loop->post, &length_se.post);
}
