When vulkan was merged into mesa's master, the following test began to fail:
src/intel/vulkan/anv_nir_lower_push_constants.c:47: lower_push_constants_block: Assertion `state->is_scalar' failed.
There are patches on the list to fix this. Unfortunately, there were about 5 different bugs that all had to be fixed before it would work.
on Feb 19, 2017 at 16:41:59.
(provided by the Example extension).