[Bug c++/102528] New: Unable to inline even trivial coroutines

["redbeard0531 at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102528

            Bug ID: 102528
           Summary: Unable to inline even trivial coroutines
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: redbeard0531 at gmail dot com
  Target Milestone: ---

https://godbolt.org/z/aoab9W4xG

This should all compile away, and test() should just be a single ret
instruction. That is not what happens now, even with -O3.

#include <coroutine>

struct simple {
    struct promise_type {
        void return_void() {}
        std::suspend_never initial_suspend() { return {}; }
        std::suspend_never final_suspend() noexcept { return {}; }
        void unhandled_exception() { throw; }
        simple get_return_object() { return {}; }
    };

    std::true_type await_ready() { return {}; }
    void await_suspend(std::coroutine_handle<>) {}
    void await_resume();
};

inline simple test1() {
    co_return;
}

inline simple test2() {
    co_await test1();
    co_return;
}

void test() {
    test2();
}