Many instruction sets (Intel, Apple, NVIDIA) implement bitwise operations with a
single general instruction that takes a lookup table in sum-of-products
(minterms) form. Working with these tables manually is a bit gnarly, and
multiple backends need to do this. This adds common code for representing such
lookup tables with 2- or 3-sources, with a rich set of helpers for building,
inspecting, and manipulating the LUTs.
Eventually, we may want to introduce a nir_op_bitop3 instruction to NIR to build
common code for fusing boolean expression trees into lookup tables. That NIR
pass will presumably use the helpers here.
NAK already has this abstraction internally (in Rust). Possibly NAK will be able
to drop (or cut down) that code once we handle this in NIR.
Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/37200>
