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We tasked Opus 4.6 using agent teams to build a C Compiler

anthropic.com

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Re: We tasked Opus 4.6 using agent teams to build a C Compiler

#101

Post by jsnell »

jeroenhd wrote: post #89
jcalvinowens wrote: post #47

How much of this result is effectively plagiarized open source compiler code? I don't understand how this is compelling at all: obviously it can regurgitate things that are nearly identical in capability to already existing code it was explicitly trained on... It's very telling how all these examples are all "look, we made it recreate a shitter version of a thing that already exists in the training set".

The fact it couldn't actually stick to the 16 bit ABI so it had to cheat and call out to GCC to get the system to boot says a lot. Without enough examples to copy from (despite CPU manuals being available in the training set) the approach failed. I wonder how well it'll do when you throw it a new/imaginary instruction set/CPU architecture; I bet it'll fail in similar ways.

"Couldn't stick to the ABI ... despite CPU manuals being available" is a bizarre interpretation. What the article describes is the generated code being too large. That's an optimization problem, not a "couldn't follow the documentation" problem.

And it's a bit of a nasty optimization problem, because the result is all or nothing. Implementing enough optimizations to get from 60kB to 33kB is useless, all the rewards come from getting to 32kB.

Re: We tasked Opus 4.6 using agent teams to build a C Compiler

#102

Post by cv5005 »

falcor84 wrote: post #75
chvid wrote: post #45

100.000 lines of code for something that is literally a text book task? I guess if it only created 1.000 lines it would be easy to see where those lines came from.

> literally a text book task Generating a 99% compliant C compiler is not a textbook task in any university I've ever heard of. There's a vast difference between a toy compiler and one that can actually compile Linux and Doom. From a bit of research now, there are only three other compilers that can compile an unmodified Linux kernel: GCC, Clang/LLVM and Intel's oneAPI. I can't find any other compiler implementation…

That's because you need to implement a bunch of gcc-specific behavior that linux relies on. A 100% standards compliant c23 compiler can't compile linux.

Re: We tasked Opus 4.6 using agent teams to build a C Compiler

#103

Post by RyanCavanaugh »

halxc wrote: post #99
antirez wrote: post #88

Earlier quoted context omitted.

The LLM does not contain a verbatim copy of whatever it saw during the pre-training stage, it may remember certain over-represented parts, otherwise it has a knowledge about a lot of things but such knowledge, while about a huge amount of topics, is similar to the way you could remember things you know very well. And, indeed, if you give it access to internet or the source code of GCC and other compilers, it will imp…

We all saw verbatim copies in the early LLMs. They "fixed" it by implementing filters that trigger rewrites on blatant copyright infringement. It is a research topic for heaven's sake: https://arxiv.org/abs/2504.16046

The internet is hundreds of billions of terabytes; a frontier model is maybe half a terabyte. While they are certainly capable of doing some verbatim recitations, this isn't just a matter of teasing out the compressed C compiler written in Rust that's already on the internet (where?) and stored inside the model.

Re: We tasked Opus 4.6 using agent teams to build a C Compiler

#104

Post by Philpax »

rubymamis wrote: post #95
Philpax wrote: post #61

Earlier quoted context omitted.

What Rust-based compiler is it plagiarising from?

There are many, here's a simple Google search: https://github.com/jyn514/saltwater https://github.com/ClementTsang/rustcc https://github.com/maekawatoshiki/rucc

Look at what those compilers are capable of compiling and to which targets, and compare it to what this compiler can do. Those are wonderful, and I have nothing but respect for them, but they aren't going to be compiling the Linux kernel.

Re: We tasked Opus 4.6 using agent teams to build a C Compiler

#105

Post by mofeien »

trilogic wrote: post #13

Can it create employment? How is this making life better. I understand the achievement but come on, wouldn´t it be something to show if you created employment for 10000 people using your 20000 USD! Microsoft, OpenAI, Anthropic, XAI, all solving the wrong problems, your problems not the collective ones.

Obviously a human in the loop is always needed and this technology that is specifically trained to excel at all cognitive tasks that humans are capable of will lead to infinite new jobs being created. /s

Re: We tasked Opus 4.6 using agent teams to build a C Compiler

#106

Post by ben_w »

halxc wrote: post #99
antirez wrote: post #88

Earlier quoted context omitted.

The LLM does not contain a verbatim copy of whatever it saw during the pre-training stage, it may remember certain over-represented parts, otherwise it has a knowledge about a lot of things but such knowledge, while about a huge amount of topics, is similar to the way you could remember things you know very well. And, indeed, if you give it access to internet or the source code of GCC and other compilers, it will imp…

We all saw verbatim copies in the early LLMs. They "fixed" it by implementing filters that trigger rewrites on blatant copyright infringement. It is a research topic for heaven's sake: https://arxiv.org/abs/2504.16046

We saw partial copies of large or rare documents, and full copies of smaller widely-reproduced documents, not full copies of everything. An e.g. 1 trillion parameter model is not a lossless copy of a ten-petabyte slice of plain text from the internet.

The distinction may not have mattered for copyright laws if things had gone down differently, but the gap between "blurry JPEG of the internet" and "learned stuff" is more obviously important when it comes to e.g. "can it make a working compiler?"

Re: We tasked Opus 4.6 using agent teams to build a C Compiler

#107

Post by small_model »

WarmWash wrote: post #35
small_model wrote: post #9

How about we get the LLM's to collaborate and design a perfect programming language for LLM coding, it would be terse (less tokens) easy for pattern searches etc and very fast to build, iterate over.

I cannot decide if LLMs would be excellent at writing in pure binary (why waste all that context on superfluous variable names and function symbols) or be absolutely awful at writing pure binary (would get hopelessly lost without the huge diversification of tokens).

We would still need the language to be human readable, but it could be very dense. They could build the ultimate std lib, that goes directly to kernels, so a call like spawn is all the tokens it needs to start a co routine for example.

Re: We tasked Opus 4.6 using agent teams to build a C Compiler

#108

Post by jsnell »

rubymamis wrote: post #95
Philpax wrote: post #61

Earlier quoted context omitted.

What Rust-based compiler is it plagiarising from?

There are many, here's a simple Google search: https://github.com/jyn514/saltwater https://github.com/ClementTsang/rustcc https://github.com/maekawatoshiki/rucc

Did you actually look at these?

> https://github.com/jyn514/saltwater

This is just a frontend. It uses Cranelift as the backend. It's missing some fairly basic language features like bitfields and variadic functions. And if I'm reading the documentation right, it requires all the source code to be in a single file...

> https://github.com/ClementTsang/rustcc

This will compile basically no real-world code. The only supported data type is "int".

> https://github.com/maekawatoshiki/rucc

This is just a frontend. It uses LLVM as the backend.

Re: We tasked Opus 4.6 using agent teams to build a C Compiler

#109

Post by rubymamis »

Philpax wrote: post #104
rubymamis wrote: post #95

Earlier quoted context omitted.

There are many, here's a simple Google search: https://github.com/jyn514/saltwater https://github.com/ClementTsang/rustcc https://github.com/maekawatoshiki/rucc

Look at what those compilers are capable of compiling and to which targets, and compare it to what this compiler can do. Those are wonderful, and I have nothing but respect for them, but they aren't going to be compiling the Linux kernel.

I just did a quick Google search only on GitHub, maybe there are better ones out there on the internet?

Re: We tasked Opus 4.6 using agent teams to build a C Compiler

#110

Post by falloutx »

ebiester wrote: post #79
sjsjsbsh wrote: post #11

> So, while this experiment excites me, it also leaves me feeling uneasy. Building this compiler has been some of the most fun I’ve had recently, but I did not expect this to be anywhere near possible so early in 2026 What? Didn’t cursed lang do something similar like 6 or 7 months ago? These bombastic marketing tactics are getting tired.

Do you not see the difference between a toy language and a clean room implementation that can compile Linux, QEMU, Postgres, and sqlite? (No, it doesn't have the assembler and linker.) That's for $20,000.

people have built compilers for free, with $20000 you can even a couple of devs for a year in low income countries.
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