Graphics processors

A graphics processor (2) comprises a programmable execution unit (65) (e.g. shader core) executing programs to perform graphics processing operations. The graphics processor further comprises a machine learning processing circuit (neural processing accelerator, NPA 78) performing processing operations for machine learning processing tasks. The machine learning processing circuit (which may include multiply-and-accumulate circuits, MAC) is in communication with the programmable execution unit internally in the graphics processor. The graphics processor is thus configured such that machine learning processing tasks can be performed by the programmable execution unit, the machine learning processing circuit, or a combination of both. The different units can message each other to control the delegation of processing tasks.