https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107079
--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Very interesting. We're in store_init_value, initializing x with
&TARGET_EXPR <D.2768, {.x=(const struct X *) &<PLACEHOLDER_EXPR struct X>}>
but we must lifetime-extend via extend_ref_init_temps and we get
_ZGR1x_.x = (const struct X *) &<PLACEHOLDER_EXPR struct X> >>>;, (const struct
X &) &_ZGR1x_;
Since x was declared constexpr, we do cxx_constant_init (not quiet) and we hit
the code added in r269003:
+ bool preeval = SCALAR_TYPE_P (type) || TREE_CODE (t) == MODIFY_EXPR;
+ if (preeval)
+ {
+ /* Evaluate the value to be stored without knowing what object it will
be
+ stored in, so that any side-effects happen first. */
+ if (!SCALAR_TYPE_P (type))
+ new_ctx.ctor = new_ctx.object = NULL_TREE;
+ init = cxx_eval_constant_expression (&new_ctx, init, false,
+ non_constant_p, overflow_p);
while evaluating the INIT_EXPR _ZGR1x_.x = (const struct X *)
&<PLACEHOLDER_EXPR struct X> >>>. But we have no ctx.ctor or ctx.object here
so lookup_placeholder won't find anything and we ICE on
7861 /* A placeholder without a referent. We can get here when
7862 checking whether NSDMIs are noexcept, or in massage_init_elt;
7863 just say it's non-constant for now. */
7864 gcc_assert (ctx->quiet);
Somehow we should manage that the PLACEHOLDER_EXPR is replaced with _ZGR1x_ I
guess.
