This paper deals with the issue of self-modifying code and packed programs, a long-standing problem commonly addressed by emulation techniques and memory dumps. We propose an original semantics-based approach to simplify dynamic code analysis, by using compiler optimization techniques to get rid of code-generating instructions. For this, we use classic slicing techniques to identify code dependencies. As it is semantics-based, our approach allows us to rely on strongly established formal methods and is a promising approach for handling packed programs.