Well, I'm using all the top models extensively on the very same codebase, my new compiler. I use deepseek for it's cheap API costs, when kimi, claude and codex are in their overbudget phase. I asked deepseek V4 Pro for an estimate of a new arm64 port. It said 4 weeks, I said, ok, do it. (I knew ncc was there, and tinycc was also known to the AI's). So it took it half an hour to produce a working arm64 port. First for arm64-elf, because this was easiest to test, and then also after more hours of back and forth the arm64-darwin port. (with crossbuild and github actions). It did cost me with all the subsequent fixes around $8 API costs.

So the experience: at the beginning deepseek was amazing. When it started to get expensive (china day time), I switched from Pro to Flash. No problem, same results. Some bitfield implementation was too complicated so I had to wait for Sonnet 4.6 tokens, kimi-2.6 did the rest. For the very hard problems I asked gpt-5.5, but this was only for one problem. minmax was horrible. didnt follow rules, and made lot of silly stuff.

But when the deepseek context window got filled, deepseek also started to become stupid. So either /clear, or /export and strip the file. And start a new session with the cleared sessions. kimi was overall better, but running into limits with my cheap moderate subscription. Paying private for it, as my companies' token budget is usually out after a week of work.

All in all it is worth it. My next compilers (perl 5+6=11) will be done with deepseek and kimi also.

regarding decompilation: recently we had to decompile a firmware for a USV we bought, but doesnt work on a new system. It only worked on a raspi. So I decompiled it with ghidra, and told my colleague, easy, that's how you do it. But my colleage didnt know about token budgets yet, and already threw opus at it. CoPilot Business account. He had working C files immediately, compilable for our new system. It ended up the USV was not beefy enough. But Opus was fantastic. The code was very short and simple C though.