If it's from inlining, then the compiler has a bug. If it's from a macro, then stop using macros in a broken fashion. Let it be an error.

How would that be a compiler bug? Assuming g() is never called with a NULL pointer, this code should not produce any compile-time errors:

    int f(int *x)
    {
      if (x == NULL) return 0;
      return *x;
    }
    
    int g(int *p)
    {
      return (*p) + f(p);
    }