Le 17/03/2024 à 23:10, Harald Anlauf a écrit :
Hi Mikael,
On 3/17/24 22:04, Mikael Morin wrote:
diff --git a/gcc/fortran/trans-array.cc b/gcc/fortran/trans-array.cc
index 3673fa40720..a7717a8107e 100644
--- a/gcc/fortran/trans-array.cc
+++ b/gcc/fortran/trans-array.cc
@@ -7526,6 +7526,17 @@ gfc_get_dataptr_offset (stmtblock_t *block,
tree parm, tree desc, tree offset,
/* Set the target data pointer. */
offset = gfc_build_addr_expr (gfc_array_dataptr_type (desc), tmp);
+
+ /* Check for optional dummy argument being present. Arguments of
BIND(C)
+ procedures are excepted here since they are handled
differently. */
+ if (expr->expr_type == EXPR_VARIABLE
+ && expr->symtree->n.sym->attr.dummy
+ && expr->symtree->n.sym->attr.optional
+ && !is_CFI_desc (NULL, expr))
I think the condition could additionally check the lack of subreferences.
But it's maybe not worth the trouble, and the patch is conservatively
correct as is, so OK.
I have thought about the conditions here for some time and did not
find better ones. They need to be broad enough to catch the case
in gfortran.dg/missing_optional_dummy_6a.f90 that (according to the
tree-dump) was not properly handled previously and would have triggered
ubsan at some point in the future when someone tried to change that
testcase from currently dg-do compile to dg-do run...
No problem, as said it is conservatively correct.
(After the patch it would pass, but I didn't dare to change the dg-do).
Did it include cases not covered by the new testcase (which was quite
complete already)?
I have pushed the patch as-is, but feel free to post testcases
not covered (or improperly covered) to narrow this down further...
The case I had in mind would only be a missed optimization, and probably
not that important, so let's move on.
