Error: bad type/size of operands for the cmov instruction

[Joseph Cassman]

I cannot figure out why I get this error

  b.d(6): Error: bad type/size of operands 'cmovz'
  Failed: 'dmd' '-v' '-o-' 'b.d' '-I.'
from the following code.

  void main() {
    asm {
      mov    CL,1;
      mov    AL,1;
      cmp    AL,0;
      cmovz  BL,CL;
    }
  }

I get the same error when I use a memory source for the cmov 
instruction, when the other variants of cmov are used, and when 
other register sizes are used (i.e. AX, EAX, and RAX).

Any ideas?