process Instruction
Process the single instruction from the source graph, transforming it as needed. Subclasses should override this to accomplish postponed instruction rewriting, code splitting, and inlining. The typical result is to rewrite some translation of the instruction to the target graph.
By default, simply transform the instruction's operands, updating the isomorphism, and emit the same kind of instruction.
Parameters
source Instruction
An L2Instruction from the source graph.