nir/cse: use the instruction set API
This replaces an O(n^2) algorithm with an O(n) one, while allowing us to import most of the infrastructure required for GVN. The idea is to walk the dominance tree depth-first, similar when converting to SSA, and remove the instructions from the set when we're done visiting the sub-tree of the dominance tree so that the only instructions in the set are the instructions that dominate the current block. No piglit regressions. No shader-db changes. Compilation time for full shader-db: Difference at 95.0% confidence -35.826 +/- 2.16018 -6.2852% +/- 0.378975% (Student's t, pooled s = 3.37504) v2: - rebase on start_block removal - remove useless state struct - change commit message Reviewed-by:Jason Ekstrand <jason.ekstrand@intel.com> Signed-off-by:
Connor Abbott <cwabbott0@gmail.com>