https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81084
--- Comment #42 from Jakub Jelinek <jakub at gcc dot gnu.org> --- See e.g. https://gcc.gnu.org/onlinedocs/gccint/ https://gcc.gnu.org/onlinedocs/gccint/#toc-RTL-Representation https://gcc.gnu.org/onlinedocs/gccint/Machine-Desc.html#Machine-Desc https://kristerw.blogspot.cz/2017/08/writing-gcc-backend_4.html and many others. Don't really know how is writing a new backend relevant to maintaining an existing one.
