Optimization of helper functions

Question

This is more or less a request for clarification on Casting a function pointer to another type with code example

struct my_struct;
void my_callback_function(struct my_struct* arg);
void do_stuff(void (*cb)(void*));

static void my_callback_helper(void* pv)
{
    my_callback_function(pv);
}
int main()
{
    do_stuff(&my_callback_helper);
}

The response says that the “good” compiler should be able to optimize my_callback_helper(), but I did not find the compiler at https://gcc.godbolt.org  , and the helper function is always generated, even if it just jumps tomy_callback_function() (-O3):

my_callback_helper:
        jmp     my_callback_function
main:
        subq    $8, %rsp
        movl    $my_callback_helper, %edi
        call    do_stuff
        xorl    %eax, %eax
        addq    $8, %rsp
        ret

So my question is: is there anything in the standard that prevents compilers from excluding the helper?

Answer 1

, . , " ".

my_callback_helper. , , do_stuff. , do_stuff , , /call my_callback_function (my_callback_helper). my_callback_helper, , do_stuff. do_stuff - , . , , do_stuff .