Guile rund om a modified version of lightning 1 (called lightening for maximum confusion) due to the recent version being more heavy weight.

It is a part of the recent JITted 3.0 release, which brought a lot better performance to the already completely OK 2.2 branch.

GNU CLISP had GNU Lightning added as an option for compiling its VM bytecode in 2008. IMO a bad decision - more maintenance burden; code can now have subtle different bugs whether run in the CLISP interpreter, CLISP bytecode VM, or CLISP bytecode compiled with GNU Lightning; generated code is much larger than bytecode (small memory use was the one unique thing CLISP has over other Common Lisp implementations); performance is still low compared to other Common Lisp compilers.

Today libgccjit seems like a much better alternative for this kind of application than GNU Lightning.