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com.c (ffecom_subscript_check_): Loosen subscript checking rules for character strings...

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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.

From-SVN: r45747
This commit is contained in:
George Helffrich 2001-09-22 19:35:05 +09:00 committed by Toon Moene
parent b8d323b1a0
commit 2bc21ba588
3 changed files with 55 additions and 10 deletions
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7
gcc/f/ChangeLog
View File

@ -1,3 +1,10 @@
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.

48
gcc/f/com.c
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@ -671,16 +671,46 @@ ffecom_subscript_check_ (tree array, tree element, int dim, int total_dims,
}
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));
}
}
{

10
gcc/f/news.texi
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@ -156,7 +156,15 @@ The following information was last updated on @value{last-update-news}:
@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