crash of channel in clang release about coroutine HOT 2 CLOSED

template <typename L>
auto write_to(channel<uint64_t, L>& ch, uint64_t value, bool ok = false)
    -> unplug
{
    ok = co_await ch.write(value);
    if (ok == false)
    {
        // inserting fprintf makes the crash disappear.
        // fprintf(stdout, "write_to %p %llx \n", &value, value);

        // !!!!!
        // seems like optimizer is removing `value`.
        // so using it in some pass makes
        // the symbol and its memory location alive
        // !!!!!
        value += 1;
    }
    REQUIRE(ok);
}

template <typename L>
auto read_from(channel<uint64_t, L>& ch, uint64_t& value, bool ok = false)
    -> unplug
{
    std::tie(value, ok) = co_await ch.read();
    REQUIRE(ok);
}