[nhaehnle]

A concrete problem that the author misses is the need for a better understanding of SPMD semantics. GLSL has the notion of "dynamically uniform" values, i.e. values that are the same across all shader threads that arise from one draw call, but this notion isn't really properly defined anywhere. It involves an unholy mixture of data flow and control flow that doesn't seem to appear anywhere else in PL theory.

Stuff kind of just works because GLSL doesn't have unstructured control-flow (i.e., there's no goto), and people have a mental model of what the hardware actually does and use that for the semantics.

But a proper study of those semantics, and how to carry it over to unstructured control-flow, or to what extent it is possible, would be awesome.