Without being glib, I honestly wonder if Fabrice Bellard has started using any LLM coding tools. If he could be even more productive, that would be scary!
I doubt he is ideologically opposed to them, given his work on LLM compression [1]
He codes mostly in C, which I'm sure is mostly "memorized". i.e. if you have been programming in C for a few decades, you almost certainly have a deep bench of your own code that you routinely go back to / copy and modify
In most cases, I don't see an LLM helping there. It could be "out of distribution", similar to what Karpathy said about writing his end-to-end pedagogical LLM chatbot
---
Now that I think of it, Bellard would probably train his own LLM on his own code! The rest of the world's code might not help that much :-)
He has all the knowledge to do that ... I could see that becoming a paid closed-source project, like some of his other ones [2]
I'm writing C for microcontrollers and ChatGPT is very good at it. I don't let it write any code (because that's the fun part, why would I), but I discuss with it a lot, asking questions, asking to review my code and he does good. I also love to use it to explain assembly.
It's also the best way to use llms in my opinion, for idea generation and snippets, and then do the thing "manually". Much better mastery of the code, no endless loop of "this creates that bug, fix it", and it comes up with plenty of feedback and gotchas when used this way.
This is a funny one because on the one hand the answer is obviously no, it's very fiddly stuff that requires a lot of umming and ahhing, but then weirdly they can be absurdly good in these kinds of highly technical domains precisely because they are often simple enough to pose to the LLM that any help it can give is actually applicable immediately whereas in a comparatively boring/trivial enterprise application there is a vast amount of external context to grapple with.
From my experience, it's just good enough to give you a code overview of a codebase you don't know and give you enough implementation suggests to work from there.
> Without being glib, I honestly wonder if Fabrice Bellard has started using any LLM coding tools
I doubt it. I follow him and look at the code he writes and it's well thought out and organized. It's the exact opposite of AI slop I see everywhere.
> He codes mostly in C, which I'm sure is mostly "memorized". i.e. if you have been programming in C for a few decades,
C I think he memorized a long time ago. It's more like he keeps the whole structure and setup of the program (the context) in his head and is able to "see it" all and operate on it. He is so good that people are insinuating he is actually "multiple people" or he uses an LLM and so on. I imagine he is quite amused reading those comments.
Most coding is better done with agents than with your hands. Coding is the main financial impediment to development. Yes, actually articulating what you want is the hard problem. Yes, there are technical problems that demand real analytical insight and real motivation. But refusing to use agents because you think you can type faster is mistaking typing for your actual skill: reasoning and interpretation.
Ok, if you have such insight into development, why not leverage agents to type for you? What sort of problems have you faced that you are able to code against faster than you can articulate to an agent?
I have of course found some problems like this myself. But it's such a tiny portion of coding I really question why you can't leverage LLMs to make yourself more productive
In 2025, there is no shame in using an LLM. For example, he might use it to get help debugging, or ask if a block of code can be written more clearly or efficiently.
> I honestly wonder if Fabrice Bellard has started using any LLM coding tools. If he could be even more productive, that would be scary!
That’s kind of a weird speculation to make about creative people and their processes.
If Caravaggio had had a computer with Photoshop, if Eintein had had a computer with Matlab, would they have been more productive? Is it a question that even makes sense?
I doubt he is ideologically opposed to them, given his work on LLM compression [1]
He codes mostly in C, which I'm sure is mostly "memorized". i.e. if you have been programming in C for a few decades, you almost certainly have a deep bench of your own code that you routinely go back to / copy and modify
In most cases, I don't see an LLM helping there. It could be "out of distribution", similar to what Karpathy said about writing his end-to-end pedagogical LLM chatbot
---
Now that I think of it, Bellard would probably train his own LLM on his own code! The rest of the world's code might not help that much :-)
He has all the knowledge to do that ... I could see that becoming a paid closed-source project, like some of his other ones [2]
[1] e.g. https://bellard.org/ts_zip/
[2] https://bellard.org/lte/