Again, it would require an extremely unlikely set of circumstances.
1) All of GCC would have to be LLM generated. If some parts are not, it's sufficient to prevent the re-licensing.
2) That someone would have to prove that all the GCC code was in fact LLM generated. Good luck doing that.
3) A court would have to decide that all the LLM-generated code does in fact fall under public domain, because it involved insufficient human input.