There's some information about why that does not happen in https://www.postgresql.org/message-id/20211104234742.ao2qzqf...

In particular:

> The immediate goal is to be able to generate JITed code/LLVM-IR that doesn't > contain any absolute pointer values. If the generated code doesn't change > regardless of any of the other contents of ExprEvalStep, we can still cache > the JIT optimization / code emission steps - which are the expensive bits.

A colleague is working on getting this patch into shape. So we might see some caching work get done after the relative pointer work is in.