Add some alignment info where LLVM might otherwise be more pessimistic. In particular, %.nest_arg is always aligned even though it's bitcast from i8*. Pointers in vtables are also guaranteed to be stored at aligned addresses.

module nested12;

extern(C) int printf(char*, ...);

void main()
{
    func();
}

void func()
{
    void a(int i)
    {
        printf("%d\n", i);
    }

    void b()
    {
        a(42);
    }

    b();
}