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 tangotests.gc1;

void main()
{
    int[] arr;

    for (int i=0; i<100; ++i)
    {
        arr ~= new int[1000];
    }

    printf("arr.length = %u\n", arr.length);
}

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