https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92431
--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> ---
This was fixed by r10-6572-dfffecb802681fbdb56629d3bdd96491ac660be0
c++: Fix static initialization from <=>.
Constant evaluation of genericize_spaceship produced a CONSTRUCTOR, which
we
then wanted to bind to a reference, which we can't do. So wrap the result
in a TARGET_EXPR so we get something with an address.
We also need to handle treating the result of cxx_eval_binary_expression as
a glvalue for SPACESHIP_EXPR.
My earlier change to add uid_sensitive to maybe_constant_value was wrong;
we
don't even look at the cache when manifestly_const_eval, and I failed to
adjust the later call to cxx_eval_outermost_constant_expr.
gcc/cp/ChangeLog
2020-02-11 Jason Merrill <ja...@redhat.com>
PR c++/93650
PR c++/90691
* constexpr.c (maybe_constant_value): Correct earlier change.
(cxx_eval_binary_expression) [SPACESHIP_EXPR]: Pass lval through.
* method.c (genericize_spaceship): Wrap result in TARGET_EXPR.
