pan/bi: Add register allocator

We model the machine as vector (with restrictions) to natively handle
mixed types and I/O and other goodies. We use LCRA for the heavylifting.
This commit adds only the modeling to feed into LCRA and spit LCRA
solutions back; next commit will integrate it with the IR.

Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4158>
4 files changed