Comment by ozgrakkurt

You are not thinking straight if you are making out of bounds errors in inline asm.

Inline asm should take 10x or more effort compared to writing the surrounding c++ code and should be tested with protected pages at the edges if possible. It should always have assertions before/after that check invariants too.

Also there are at a lot of cases that this won’t work. One example is implementing strlen using avx512 where you want to align the address down to a multiple of 64 and run until the end of the page, so you can do simd while avoiding segfault.

Another example is just handling loop remainders with masking in avx512.

Also it is pretty naive to think an LLM got this right

Overall it seems like a huge waste of time.

If you are writing inline asm and want to make it better, just get as many LLMs or, even better, humans to review it. LLMs are really good at finding mistakes in inline asm, with a high false positive rate though, so you have to understand the concept.

For example one bug I had was about not consuming the inputs before writing to the outputs. Compiler can assign the same register to input and outputs unless outputs are marked with & (or something like that). It was super frustrating to debug this until I asked an LLM and it found the problem.