On 05/21/15 21:47, Jason Merrill wrote:
How about adding may_alias support to the code a bit lower down that copies the
abi_tag attribute?
Good idea. This keeps the non-copy behavior when the attribute is the last on
the source attribute list, and fixes up the case for when there are both
may_alias and abi_tag.
booted and tested on x86_64-linux
ok?
nathan
2015-05-22 Nathan Sidwell <nat...@acm.org>
PR c++/65936
* pt.c (lookup_template_class_1): Copy may_alias attribute too.
PR c++/65936
* g++.dg/template/pr65936.C: New.
Index: cp/pt.c
===================================================================
--- cp/pt.c (revision 223503)
+++ cp/pt.c (working copy)
@@ -7905,15 +7905,22 @@ lookup_template_class_1 (tree d1, tree a
if (OVERLOAD_TYPE_P (t)
&& !DECL_ALIAS_TEMPLATE_P (gen_tmpl))
{
- if (tree attributes
- = lookup_attribute ("abi_tag", TYPE_ATTRIBUTES (template_type)))
+ static const char *tags[] = {"abi_tag", "may_alias"};
+
+ for (unsigned ix = 0; ix != 2; ix++)
{
- if (!TREE_CHAIN (attributes))
+ tree attributes
+ = lookup_attribute (tags[ix], TYPE_ATTRIBUTES (template_type));
+
+ if (!attributes)
+ ;
+ else if (!TREE_CHAIN (attributes) && !TYPE_ATTRIBUTES (t))
TYPE_ATTRIBUTES (t) = attributes;
else
TYPE_ATTRIBUTES (t)
- = build_tree_list (TREE_PURPOSE (attributes),
- TREE_VALUE (attributes));
+ = tree_cons (TREE_PURPOSE (attributes),
+ TREE_VALUE (attributes),
+ TYPE_ATTRIBUTES (t));
}
}
Index: testsuite/g++.dg/template/pr65936.C
===================================================================
--- testsuite/g++.dg/template/pr65936.C (revision 0)
+++ testsuite/g++.dg/template/pr65936.C (working copy)
@@ -0,0 +1,21 @@
+// checking ICE in canonical typing
+
+class A;
+
+template <typename> struct B
+{
+ typedef A type;
+};
+
+template <class T> class C
+ : public B<T>::type
+{
+} __attribute__ ((__may_alias__));
+
+class A
+{
+ operator const C<int> &()
+ {
+ return *static_cast<const C<int> *> (this);
+ }
+};
