On Wed, Mar 29, 2017 at 12:38 PM, Marek Polacek <pola...@redhat.com> wrote:
> Here we have a reference initialization with NSDMI and *this. We are crashing
> because a PLACEHOLDER_EXPR crept into the gimplifier.
>
> This happens since r218653 where set_up_extended_ref_temp was changed to
> use split_nonconstant_init. As a consequence, cp_gimplify_init_expr might
> now be receiving
>
> D.2051.p = (void *) &<PLACEHOLDER_EXPR struct A>
>
> instead of
>
> D.2051 = {.p = (void *) &<PLACEHOLDER_EXPR struct A>}
>
> where the RHS was a CONSTRUCTOR. It no longer is, so replace_placeholders is
> not called anymore. It occurred to me that we should use the same check as in
> store_init_value (i.e. check that the object to be used in the substitution is
> a class), but given what split_nonconstant_init might produce, handle
> COMPONENT_REFs specially.
>
> Bootstrapped/regtested on x86_64-linux, ok for trunk and 6?
>
> 2017-03-29 Marek Polacek <pola...@redhat.com>
>
> PR c++/80095 - ICE with this pointer in NSDMI.
> * cp-gimplify.c (cp_gimplify_init_expr): Call replace_placeholders
> when TO is a class.
>
> * g++.dg/cpp1y/nsdmi-aggr8.C: New test.
>
> diff --git gcc/cp/cp-gimplify.c gcc/cp/cp-gimplify.c
> index 354ae1a..e530daf 100644
> --- gcc/cp/cp-gimplify.c
> +++ gcc/cp/cp-gimplify.c
> @@ -496,7 +496,16 @@ cp_gimplify_init_expr (tree *expr_p)
> TREE_TYPE (from) = void_type_node;
> }
>
> - if (cxx_dialect >= cxx14 && TREE_CODE (sub) == CONSTRUCTOR)
> + /* split_nonconstant_init might've produced something like
> + D.2051.p = (void *) &<PLACEHOLDER_EXPR struct A>
> + in which case we want to substitute the placeholder with
> + D.2051. */
> + tree op0 = to;
> + while (TREE_CODE (op0) == COMPONENT_REF)
> + op0 = TREE_OPERAND (op0, 0);
> + tree type = TREE_TYPE (op0);
> +
> + if (cxx_dialect >= cxx14 && CLASS_TYPE_P (strip_array_types (type)))
How about doing this checking in replace_placeholders, instead? That
is, if the object isn't a (member of a) class, just return.
Jason
