I’m generating about 1000 test cases, a few hundred instructions each. This process takes 195 seconds on my PC. According to cProfile 64% of the time is spent in deepcopy, which is quite a bit. Below is a full call graph generated with gprof2dot:

Apparently each of the two steps (ABIFunction, EncodedFunction) involved deepcopy()ies all instruction objects, which are quite heavy. If deepcopy() could be – somehow – avoided the whole process would be alot faster.