nir: Add and use some deref mode helpers
NIR derefs currently have exactly one variable mode. This is about to
change so we can handle OpenCL generic pointers. In order to transition
safely, we need to audit every deref->mode check. This commit adds a
set of helpers that provide more nuanced mode checks and converts most
of NIR to use them.
For simple cases, we add nir_deref_mode_is and nir_deref_mode_is_one_of
helpers. These can be used in passes which don't have to bother with
generic pointers and just want to know what mode a thing is. If the
pass ever encounters generic pointers in a way that this check would be
unsafe, it will assert-fail to alert developers that they need to think
harder about things and fix the pass.
For more complex passes which require a more nuanced understanding of
modes, we add nir_deref_mode_may_be and nir_deref_mode_must_be helpers
which accurately describe the compiler's best knowledge about the given
deref. Unfortunately, we may not be able to exactly identify the mode
in a generic pointers scenario so we have to be very careful when we use
these. Conversion of these passes is left to later commits.
For the case of mass lowering of a particular mode (nir_lower_explicit_io
is one good example), we add nir_deref_mode_is_in_set. This is also
pretty assert-happy like nir_deref_mode_is but is for a set containment
comparison on deref modes where you expect the deref to either be all-in
or all-out.
Reviewed-by: Jesse Natalie <jenatali@microsoft.com>
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6332>
25 files changed
