but there is a difference between deterministic compilation and non-deterministic LLM code. Of course I don't think this is an issue for toy problems and simple codebases, but for non-trivial problems I think it will be an issue. When I compile C code I know that maybe it will not be as efficient as it could be if I had written it in Assembly, but there will be a biunivocal correspondence between C and Assembly. If instead I use an LLM to rewrite a feature of a codebase I can't be sure that it still functions like the original one. I acknowledge that this is an issue with human programmers too, but I don't see a clear way forward, even if I'm really interested in LLM compilers being a thing. Maybe we will use them for non important code, and we will keep writing system critical stuff by hand.

> but there is a difference between deterministic compilation and non-deterministic LLM code

But not the point of my comment. Computer programming has been a progression of physically wiring up valves, to soldering transistors, to punched cards, assembly, then higher level languages. Now we have natural language models.

The analogy being each that most people don't care about the assembly generated as the code works and it's really performant/efficient. Humans can still optimise assembly, but there's vanishingly small marginal gains for all but the most intensive/low-level tasks.

If LLMs produce things that work, and are indistinguishable from a careful human programmer (i.e. with some level of acceptable performance), people will simply stop looking at the high level code as the end result works, in the same way most people stopped looking at generated assembly after 8 bit computers (for example, as most games were written in raw assembly for... perforamance), as it was good enough.

> If instead I use an LLM to rewrite a feature of a codebase I can't be sure that it still functions like the original one.

Right now, with existing static analysis tooling, you can ask it to write a full suite of unit tests capturing existing behaviour without modifying the existing code with 100% code coverage, and start there. Plus fuzz tests as well. I actually have marginally more confidence in that than a human being doing it.