Our collaboration around the Coccinelle tool aims at streamlining maintenance of large software projects in HPC.We are developing techniques to modify large swathes of C/C++ codes and introduce e.g.:GPU support, replace an API with another, introduce modern C++ according to guidelines, change parallelism model.Our aims are: minimization of code rewriting, preserving the value and extending the lifetime of well written old code, saving energy by making code more efficient. This poster summarizes our recent efforts.