nir/opt_deref: Properly optimize ptr_as_array derefs
When handling casts, we can't blindly propagate the parent of a cast into a ptr_as_array deref because doing so might loose the stride information from the cast. Instead, before we can propagate into ptr_as_array derefs, we need to check that the cast is a cast of an array deref and that the stride matches. For other types of derefs, we can continue to propagate casts as normal because they don't need the stride. We also add an optimization which can combine a ptr_as_array deref with it parent if it is also an array deref of some form. Reviewed-by:Alejandro Piñeiro <apinheiro@igalia.com> Reviewed-by:
Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>