One embodiment of the present invention sets forth an architecture for optimizing graphics rendering efficiency by advancing the Z-test operation prior to pixel shading whenever possible. The current rendering state, as maintained by the setup engine, determines whether advancing the Z-test function above the shader engine for "early" Z-testing is possible or whether the Z-test function should be deferred until after shading operations for "late" Z-testing. Data is dynamically routed to each processing engine in the pipeline, so that the appropriate data flow for either early Z or late Z is dynamically constructed, as determined by the current rendering state. Efficiency is gained by relieving the shader engine of unnecessary work whenever possible by discarding pixels before they enter the shader engine. The same functional units are utilized in both early Z and late Z configurations, minimizing any additional hardware required for implementation.