[Mesa-dev] [PATCH 00/24] i965: Refactor register classes

[Matt Turner]

backend_reg (from which fs_reg, src_reg, and dst_reg inherit) includes a
brw_reg that's used for "hardware regs" -- precolored registers or architecture
registers. This leads to properties like source modifiers, the register type,
swizzles, and writemasks being duplicated between the derived classes and the
brw_reg and of course often being out of sync.

This series removes the "fixed_hw_reg" field from backend_reg by just making
backend_reg inherit from brw_reg, and then removes fields duplicated in the
derived classes. In the process, it gets rid of HW_REG.

This in turn simplifies a lot of code -- no longer do you have to check a
number of subfields if file == HW_REG.

The last few patches begin some clean ups -- since the base of our register
classes is now brw_reg we don't need to do as many conversions. I've only
handled immediates so far and more is planned, but the series is growing large
and is a lot of churn already.

The sizes of the register classes all shrink by 8 bytes:

   backend_reg   20 -> 12
   fs_reg        40 -> 32
   src_reg       32 -> 24?
   dst_reg       32 -> 24?

The remaining fields in the classes are

   backend_reg: reg_offset
   fs_reg:      reladdr, subreg_offset, stride
   src_reg      reladdr
   dst_reg      reladdr