[Bug c++/105838] [10/11/12/13 Regression] g++ 12.1.0 runs out of memory or time when building const std::vector of std::strings

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105838

--- Comment #19 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jason Merrill <jason@gcc.gnu.org>:

https://gcc.gnu.org/g:bd0485f20f4794f9787237706a6308473a8e9415

commit r13-4565-gbd0485f20f4794f9787237706a6308473a8e9415
Author: Jason Merrill <jason@redhat.com>
Date:   Tue Dec 6 18:10:48 2022 -0500

    c++: build initializer_list<string> in a loop [PR105838]

    The previous patch avoided building an initializer_list<string> at all when
    building a vector<string>, but in situations where that isn't possible, we
    could still build the initializer_list with a loop over a constant array.

    This is represented using a VEC_INIT_EXPR, which required adjusting a
couple
    of places that expected the initializer array to have the same type as the
    target array and fixing build_vec_init not to undo our efforts.

            PR c++/105838

    gcc/cp/ChangeLog:

            * call.cc (convert_like_internal) [ck_list]: Use
            maybe_init_list_as_array.
            * constexpr.cc (cxx_eval_vec_init_1): Init might have
            a different type.
            * tree.cc (build_vec_init_elt): Likewise.
            * init.cc (build_vec_init): Handle from_array from a
            TARGET_EXPR.  Retain TARGET_EXPR of a different type.

    gcc/testsuite/ChangeLog:

            * g++.dg/tree-ssa/initlist-opt2.C: New test.