GCC Backend

https://gcc.gnu.org/onlinedocs/gccint/RTL-passes.html

https://users.suse.com/~mliska/doxygen/ira_8h.html

https://gcc.gnu.org/onlinedocs/gccint/Back-End.html

https://kristerw.blogspot.com/2017/08/writing-gcc-backend_4.html

http://atgreen.github.io/ggx/

https://gcc.gnu.org/onlinedocs/gccint/Machine-Modes.html#Machine-Modes