OK.
On Wed, Apr 5, 2017 at 5:37 PM, Marek Polacek <pola...@redhat.com> wrote:
> We crashed on this testcase because UNDERLYING_TYPE, a C++-specific code,
> got into layout_type. It wound up there via strip_typedefs -> ... ->
> build_type_attribute_qual_variant and that calls type_hash_canon which
> has
> 7129 /* The TYPE_ALIGN field of a type is set by layout_type(), so we
> 7130 must call that routine before comparing TYPE_ALIGNs. */
> 7131 layout_type (type);
> I think best would be to fix this in strip_typedefs, much like how we handle
> some other _TYPE nodes.
>
> I checked in gdb what results we get and it seems that strip_typedefs now
> returns what I would expect it to, i.e. an UNDERLYING_TYPE with the attribute
> removed.
>
> Bootstrapped/regtested on x86_64-linux, ok for trunk?
>
> 2017-04-05 Marek Polacek <pola...@redhat.com>
>
> PR c++/80244 - ICE with attribute in template alias.
> * tree.c (strip_typedefs): Handle UNDERLYING_TYPE.
>
> * g++.dg/cpp0x/alias-decl-59.C: New test.
>
> diff --git gcc/cp/tree.c gcc/cp/tree.c
> index 2757af6..1f0e422 100644
> --- gcc/cp/tree.c
> +++ gcc/cp/tree.c
> @@ -1531,6 +1531,10 @@ strip_typedefs (tree t, bool *remove_attributes)
> DECLTYPE_TYPE_ID_EXPR_OR_MEMBER_ACCESS_P (t),
> tf_none));
> break;
> + case UNDERLYING_TYPE:
> + type = strip_typedefs (UNDERLYING_TYPE_TYPE (t), remove_attributes);
> + result = finish_underlying_type (type);
> + break;
> default:
> break;
> }
> diff --git gcc/testsuite/g++.dg/cpp0x/alias-decl-59.C
> gcc/testsuite/g++.dg/cpp0x/alias-decl-59.C
> index e69de29..1f5e94f 100644
> --- gcc/testsuite/g++.dg/cpp0x/alias-decl-59.C
> +++ gcc/testsuite/g++.dg/cpp0x/alias-decl-59.C
> @@ -0,0 +1,11 @@
> +// PR c++/80244
> +// { dg-do compile { target c++11 } }
> +
> +template<typename>
> +struct A {};
> +
> +template<typename T>
> +using B = A<__underlying_type(T) [[gnu::aligned(4)]]>; // { dg-warning
> "ignoring attributes on template argument" }
> +
> +template<typename T>
> +using B = A<__underlying_type(T) [[gnu::packed]]>; // { dg-warning "ignoring
> attributes on template argument" }
>
> Marek
