------- Comment #5 from fxcoudert at gcc dot gnu dot org 2007-03-18 23:03
-------
When creating a testcase for this one, I found we have a similar problem with
character functions:
$ cat a.f90
program test
print *, len(bar(-1))
contains
function bar(i)
integer, intent(in) :: i
character(len=i) :: bar
bar = ""
end function bar
end program test
$ gfortran a.f90 && ./a.out
Fortran runtime error: Attempt to allocate a negative amount of memory.
Complete patch is:
Index: trans-expr.c
===================================================================
--- trans-expr.c (revision 123028)
+++ trans-expr.c (working copy)
@@ -227,6 +227,8 @@
gfc_init_se (&se, NULL);
gfc_conv_expr_type (&se, cl->length, gfc_charlen_type_node);
+ se.expr = fold_build2 (MAX_EXPR, gfc_charlen_type_node, se.expr,
+ build_int_cst (gfc_charlen_type_node, 0));
gfc_add_block_to_block (pblock, &se.pre);
tmp = cl->backend_decl;
@@ -2256,6 +2258,8 @@
}
else
{
+ tree tmp;
+
/* Calculate the length of the returned string. */
gfc_init_se (&parmse, NULL);
if (need_interface_mapping)
@@ -2264,7 +2268,11 @@
gfc_conv_expr (&parmse, sym->ts.cl->length);
gfc_add_block_to_block (&se->pre, &parmse.pre);
gfc_add_block_to_block (&se->post, &parmse.post);
- cl.backend_decl = fold_convert (gfc_charlen_type_node, parmse.expr);
+
+ tmp = fold_convert (gfc_charlen_type_node, parmse.expr);
+ tmp = fold_build2 (MAX_EXPR, gfc_charlen_type_node, tmp,
+ build_int_cst (gfc_charlen_type_node, 0));
+ cl.backend_decl = tmp;
}
/* Set up a charlen structure for it. */
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31203
