Finding Miscompiles for Fun, Not Profit
A developer spent over $10,000 on AI agents to find bugs in the LLVM compiler. Initially, they found five bugs in LLVM's instcombine but later discovered 80 miscompiles in NVIDIA's ptxas compiler. The project highlights the effectiveness of using AI for bug detection in compilers.
- ▪The developer has experience working on compilers for machine learning at major tech companies.
- ▪They initially found five bugs in LLVM before shifting focus to NVIDIA's ptxas compiler.
- ▪In just three days, they identified 40 miscompiles in ptxas, which increased to 80 within a week.
Opening excerpt (first ~120 words) tap to expand
Finding Miscompiles for Fun, Not ProfitOr: You don’t need access to Claude Mythos to spend $10,000 in an afternoon.Justin LebarMay 28, 2026∙ Paid1261ShareI’ve worked on compilers for ML for the last decade across Google, Waymo, and OpenAI. This includes CUDA support in clang, XLA:GPU, Triton, and OpenAI’s custom hardware. I’ve seen stuff. But over the past week or so I had one of the unsettling experiences of my career: In one afternoon, I spent more than $10,000 running AI agents over compiler code, finding hundreds of plausible bugs in LLVM, including many miscompiles and at least one that’s Quite Serious.
…
Excerpt limited to ~120 words for fair-use compliance. The full article is at Hacker News (Newest).
Discussion
0 commentsMore from Hacker News (Newest)
