The aim of this work is to design a method that simplifies two programs based on the results of analysis of their semantic difference. The goal is to remove as many semantically equivalent parts of the programs as possible. To find these equivalent parts, we apply our own solution to the problem of finding the maximum common induced subgraph. Subsequently, we are able to simplify the programs by using backward static slicing. By applying this simplification, we obtain sliced programs that consist of the differing parts and parts that can affect these differences. The method has been implemented as an extension of the DiffKemp tool, which is a static analyser of semantic differences between different versions of large scale programs. Our experiments on the Linux kernel show that the method is able to produce correct slices very efficiently (the analysis is prolonged only by 3.2%). Moreover, the created slices are much smaller than the original programs, which makes them suitable for further analysis.