BigInt give incorrect results for a^^b for a select set of numbers:

12 ^^ 16
48 ^^ 8
48 ^^ 16
80 ^^ 8
112 ^^ 8
144 ^^ 8
176 ^^ 8
192 ^^ 16
208 ^^ 8
etc

Test case:

void main()
{
  BigInt bpow(long a, long b)
  {
    auto r = BigInt(1);
    while(b--)
      r *= a;
    return r
  }

  foreach(a; 0..1000)
  {
    foreach(b; 0..1000)
    {
    	auto r1 = bpow(a, b);
    	auto r2 = BigInt(a) ^^ b;
    	assert(r1 == r2);
    }
  }
}

Version of std.bigint packaged with dmd2.047
Have not checked on other hardware/os