Cutpoints for formal equivalence verification of embedded software

Like hardware, embedded software faces stringent design constraints, undergoes extremely aggressive optimization, and therefore has a similar need for verifying the functional equivalence of two versions of a design, e.g., before and after an optimization. The concept of cutpoints was a breakthrough in the formal equivalence verification of combinational circuits and is the key enabling technology behind its successful commercialization. We introduce an analogous idea for formally verifying the equivalence of structurally similar, "combinational" software, i.e., software routines that compute a result and return/terminate, rather than executing indefinitely. We have implemented a proof-of-concept cutpoint approach in our prototype verification tool for the TI C6x family of VLIW DSPs, and our experiments show large improvements in runtime and memory usage.