Re: [PR c++/84593] ice on braced init with uninit ref field

[Jason Merrill <jason at redhat dot com>]

On Fri, Mar 2, 2018 at 2:57 AM, Alexandre Oliva <aoliva@redhat.com> wrote:
> On Feb 28, 2018, Jason Merrill <jason@redhat.com> wrote:
>
>> On Wed, Feb 28, 2018 at 7:08 AM, Alexandre Oliva <aoliva@redhat.com> wrote:
>>> Don't allow the initializer expr to be NULL in a ctor initializer
>>> list, make it error_marker_node instead.
>
>> I don't want error_mark_nodes in a CONSTRUCTOR, either.  When there
>> isn't an NSDMI to worry about, we zero-initialize the reference, and
>> it seems reasonable to continue doing that, by fixing
>> build_zero_init_1 to return something non-null for a reference.
>
> Like this?  Regstrapped on i686- and x86_64-linux-gnu.
>
> [PR c++/84593] ice on braced init with uninit ref field
>
> If an initializer expr is to be NULL in a ctor initializer list, we
> ICE in picflag_from_initializer and elsewhere.
>
> If we're missing an initializer for a reference field, we report the
> error, but then build a zero initializer to avoid the ICE.
>
> for  gcc/cp/ChangeLog
>
>         PR c++/84593
>         * init.c (build_zero_init_1): Zero-initialize references.
>
> for  gcc/testsuite/ChangeLog
>
>         PR c++/84593
>         * g++.dg/cpp1y/pr84593.C: New.
> ---
>  gcc/cp/init.c                        |    5 ++++-
>  gcc/testsuite/g++.dg/cpp1y/pr84593.C |    8 ++++++++
>  2 files changed, 12 insertions(+), 1 deletion(-)
>  create mode 100644 gcc/testsuite/g++.dg/cpp1y/pr84593.C
>
> diff --git a/gcc/cp/init.c b/gcc/cp/init.c
> index d0d14abdc9fa..ed28e9a46dbc 100644
> --- a/gcc/cp/init.c
> +++ b/gcc/cp/init.c
> @@ -284,7 +284,10 @@ build_zero_init_1 (tree type, tree nelts, bool static_storage_p,
>    else if (VECTOR_TYPE_P (type))
>      init = build_zero_cst (type);
>    else
> -    gcc_assert (TREE_CODE (type) == REFERENCE_TYPE);
> +    {
> +      gcc_assert (TREE_CODE (type) == REFERENCE_TYPE);
> +      init = fold (convert (type, integer_zero_node));

Maybe build_zero_cst?

OK either way.

Jason