Building on the existing MLIR integer interval range analysis framework, build the interface for the comb dialect. Use the interval range analysis to develop a comb opt narrowing pass, that reduces a comb opt based on the interval range of the operation. Currently this is only supported for addition, subtraction and multiplication, but this could be extended in the future. Future work will leverage the interval analysis to validate the combination of consecutive addition operators into a multi-operand addition.
Some operations in the comb dialect (e.g. comb.truth_table) are not directly supported by ExportVerilog. They need to be lowered into ops which are supported. There are many ways to lower these ops so we do this in a separate pass. This also allows the lowered form to participate in optimizations like the comb canonicalizers. This change is just to introduce the pass boilerplate. It currently doesn't do anything.
Samuel Coward