Important applications like quantum search and quantum simulation rely on control flow implemented by oracle circuits, which may account for up to 99% of the total gate count as orcale circuits consist of expensive multi-controlled (MC) quantum gates to formulate the control flow. Existing efforts optimize them by simplifying Boolean expressions associated with MC gates. They merge MC gates, if associated Boolean expressions are adjacent, to reduce the gate cost. Being more aggressive, our work introduces control line encoding, a technique that even allows merging non-adjacent MC gates by modifying their control (line) polarity. We further develop a plug-in compiler companion that efficiently applies this technique. Experiments demonstrate that, compared to the baseline, our work further reduces the CX and T cost, on average by 54.7% and 56.8%, respectively.