[Mesa-dev] r600g: Support spilling temp arrays

[Glenn Kennard]

This patch series implements support for spilling temporary arrays on
R6xx/R7xx/Evergreen/NI if hardware GPR limits are exceeded. It opts for a
simple pessimistic scheme of spilling the largest arrays until things fit.

This fixes some subset of issues where "GPR limit exceeded" or "TGSI
translation error" is printed to the console.

Exercises left to reader:
* Test on R600/R700, I suspect R600 in particular might need some additional
  fixups for write masking in tgsi_src().
* Implement support for spilling regular TGSI temps. Most of the
  infrastructure needed is in this patch series so should be straightforward.
  This would fix the remaining GPR limit exceeded issues.