Re: [C++ PATCH] PR 70501, ICE in verify ctor sanity

[Jason Merrill <jason at redhat dot com>]

On 04/04/2016 01:26 PM, Nathan Sidwell wrote:
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70501
>
> This fixes 70501.  The cause is an omission in typeck when converting a
> scalar operand to a vector.  We use build_vector_from_val, which can
> return a CONSTRUCTOR.  We fail to wrap that CONSTRUCTOR in a TARGET_EXPR.
>
> The ICE arises because at the point we meet that CONSTRUCTOR during the
> constexpr processing, the currently active object under construction is
> that for the result of the <= operator, which has type vector-of-bool,
> rather than vector-of-int. (thus this  problem arises in other vector
> ops, but mostly undetected because the result type is the same  as the
> operand type)

It's not clear to me that we really need a TARGET_EXPR for vector 
values.  Since one element of a vector can't refer to another, we don't 
need the ctx->ctor handling.  Perhaps we should handle vectors like we 
do PMF types in cxx_eval_bare_aggregate?

Jason