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 typeinfo4;

void main()
{
    auto ti = typeid(void*);
    assert(ti.toString() == "void*");
    assert(ti.tsize() == size_t.sizeof);
    void* a = null;
    void* b = a + 1;
    assert(ti.compare(&a,&b) < 0);
}