[Bug c++/114114] [11/12/13/14 Regression] Internal compiler error on function-local conditional noexcept

["cvs-commit at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114114

--- Comment #4 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The trunk branch has been updated by Marek Polacek <mpolacek@gcc.gnu.org>:

https://gcc.gnu.org/g:dc6c3bfb59baab28b998e18396c06087b6d9b0ed

commit r14-9339-gdc6c3bfb59baab28b998e18396c06087b6d9b0ed
Author: Marek Polacek <polacek@redhat.com>
Date:   Tue Mar 5 13:33:10 2024 -0500

    c++: ICE with noexcept and local specialization [PR114114]

    Here we ICE because we call register_local_specialization while
    local_specializations is null, so

      local_specializations->put ();

    crashes on null this.  It's null since maybe_instantiate_noexcept calls
    push_to_top_level which creates a new scope.  Normally, I would have
    guessed that we need a new local_specialization_stack.  But here we're
    dealing with an operand of a noexcept, which is an unevaluated operand,
    and those aren't registered in the hash map.  maybe_instantiate_noexcept
    wasn't signalling that it's substituting an unevaluated operand though.

            PR c++/114114

    gcc/cp/ChangeLog:

            * pt.cc (maybe_instantiate_noexcept): Save/restore
            cp_unevaluated_operand, c_inhibit_evaluation_warnings, and
            cp_noexcept_operand around the tsubst_expr call.

    gcc/testsuite/ChangeLog:

            * g++.dg/cpp0x/noexcept84.C: New test.