nir: improve divergence analysis and disallow some reordering of loads with dynamic resource indexing
This includes changes from !5201 (merged) , along with some changes that are needed to not break non-uniform indexing
Due to an influx of spam, we have had to impose restrictions on new accounts. Please see this wiki page for instructions on how to get full permissions. Sorry for the inconvenience.
This includes changes from !5201 (merged) , along with some changes that are needed to not break non-uniform indexing