Yeah, but nobody is seriously considering that unless maybe for huge prepared statements. The argument is usually bytecode vs parser and associated data structures.
I don't have personal experience on it, but I've read that in practice it's not worth the effort—at least not yet. Apparently there are some issues with it and it barely speeds up queries (except perhaps certain ones?). I imagine this could be in big part because LLVM is not really a good fit for JIT where you want to spend very little time to do the compilation itself.
Yeah my experience of the pg jit is mostly negative, it’s quite slow and it has a hard time estimating the cost of interpreted v compilation + compiled execution so more often than not it’s actively detrimental. It might fare better if you make heavy use of a limited number of prepared statements.