+Thu Sep 20 15:05:20 JST 2001 George Helffrich <george@geo.titech.ac.jp>
+
+ * com.c (ffecom_subscript_check_): Loosen subscript checking rules
+ for character strings, to permit substring expressions like
+ string(1:0).
+ * news.texi: Document this as a new feature.
+
Thu Sep 13 10:33:27 2001 Kaveh R. Ghazi <ghazi@caip.rutgers.edu>
* bad.c (ffebad_finish): Const-ification and/or static-ization.
}
element = ffecom_save_tree (element);
- cond = ffecom_2 (LE_EXPR, integer_type_node,
- low,
- element);
- if (high)
+ if (total_dims == 0)
{
- cond = ffecom_2 (TRUTH_ANDIF_EXPR, integer_type_node,
- cond,
- ffecom_2 (LE_EXPR, integer_type_node,
- element,
- high));
+ /* Special handling for substring range checks. Fortran allows the
+ end subscript < begin subscript, which means that expressions like
+ string(1:0) are valid (and yield a null string). In view of this,
+ enforce two simpler conditions:
+ 1) element<=high for end-substring;
+ 2) element>=low for start-substring.
+ Run-time character movement will enforce remaining conditions.
+
+ More complicated checks would be better, but present structure only
+ provides one index element at a time, so it is not possible to
+ enforce a check of both i and j in string(i:j). If it were, the
+ complete set of rules would read,
+ if ( ((j<i) && ((low<=i<=high) || (low<=j<=high))) ||
+ ((low<=i<=high) && (low<=j<=high)) )
+ ok ;
+ else
+ range error ;
+ */
+ if (dim)
+ cond = ffecom_2 (LE_EXPR, integer_type_node, element, high);
+ else
+ cond = ffecom_2 (LE_EXPR, integer_type_node, low, element);
+ }
+ else
+ {
+ /* Array reference substring range checking. */
+
+ cond = ffecom_2 (LE_EXPR, integer_type_node,
+ low,
+ element);
+ if (high)
+ {
+ cond = ffecom_2 (TRUTH_ANDIF_EXPR, integer_type_node,
+ cond,
+ ffecom_2 (LE_EXPR, integer_type_node,
+ element,
+ high));
+ }
}
{
@itemize @bullet
@ifclear USERVISONLY
@item
-[ Nothing yet ]
+George Helffrich (@email{george@@geo.titech.ac.jp}) implemented a change
+in substring index checking (when specifying @code{-fbounds-check})
+that permits the use of zero length substrings of the form
+@code{string(1:0)}.
+
+@item
+Based on code developed by Pedro Vazquez (@email{vazquez@@penelope.iqm.unicamp.br}),
+the @code{libf2c} library is now able to read and write files larger than
+2 Gbyte on 32-bit target machines, if the operating system supports this.
@end ifclear
@end itemize