[Bug c++/126312] Bad ARM64 codegen: mandatory copy elision not enforced creates dangling reference

[gufideg at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126312

Guillaume Racicot <gufideg at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|middle-end                  |c++

--- Comment #1 from Guillaume Racicot <gufideg at gmail dot com> ---
Something happened when editing the text. Here's the full example without the
paragraph in the middle. Changed the component to be C++:

    struct val_ref {
        constexpr val_ref() : val(42), ref(val) {}
        val_ref(val_ref&&) = delete;
        val_ref(val_ref const&) = delete;
        int val;
        int& ref;
    };

    struct wrapper {
        constexpr wrapper(): impl{} {}
        val_ref impl{};
    };

    constexpr auto make_s() {
        return wrapper{};
    }

    constexpr int test() {
        auto s = make_s();
        return s.impl.ref;
    }

    //static_assert(test());

    int main() {
        return test() == 42 ? 0 : 1;
    }