Just as a heads up, you may have noticed that revision D136183 completely removed vectorization support from the sparse compiler.
Wait! What?! Can it be that the author of the The Software Vectorization Handbook no longer cares about SIMD?!
Rest assured. Quite the opposite! But we want to do vectorization of sparse code the right way, through progressive lowering and clean separation of concerns. So expect to see this functionality restored soon again, but then done the right way (so in a way, this too, is a spin-off result of our [RFC] Structured Codegen Beyond Rectangular Arrays).