// reg1 = reg2 + const
            public static Tile Reg_AddConst()
            {
                return(new Tile(typeof(AssignmentNode),
                                new[] {
                    makeTile <RegisterNode> (),
                    makeTile <AddOperatorNode> (
                        makeTile <RegisterNode> (),
                        makeTile <ConstantNode <long> > ()
                        )
                },
                                (regNode, node) => {
                    var root = node as AssignmentNode;
                    var reg1 = root.Target as RegisterNode;
                    var addop = root.Source as AddOperatorNode;
                    var reg2 = addop.LeftOperand as RegisterNode;
                    var val = addop.RightOperand as ConstantNode <long>;

                    // reg = reg + 1 -> reg++
                    if (reg1 == reg2 && val.Value == 1L)
                    {
                        return new[] {
                            InstructionFactory.Inc(reg1),
                            InstructionFactory.Move(regNode, reg1)
                        };
                    }
                    else
                    {
                        return new[] {
                            InstructionFactory.Move(reg1, reg2),                                       // r = left
                            InstructionFactory.Add(reg1, val),                                         // r = left + right
                            InstructionFactory.Move(regNode, reg1)
                        };
                    }
                }
                                ));
            }