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 g;

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

void func(char[] str)
{
    printf("%.*s\n", str.length, str.ptr);
}

void main()
{
    char[] arr = "Hello World!";
    func(arr);
    func("ditto");
}