Implicitly parallel programming systems must solve the joint problems of dependence analysis and coherence to ensure apparently-sequential semantics for applications run on distributed memory machines. Solving these problems in the presence of data-dependent control flow and arbitrary aliasing is a challenge that most existing systems eschew by compromising the expressivity of their programming models and/or the performance of their implementations. We demonstrate a general class of solutions to these problems via a reduction to the visibility problem from computer graphics.