Ex-OpenAI Tech Lead, Justin Lebar joins SemiAnalysis as an Visiting Fellow to Burn $10,000 in 3 hours to find dozens of …
SemiAnalysis Twitter · SemiAnalysis (@SemiAnalysis_) · 2026-06-04
Ex-OpenAI tech lead Justin Lebar joins SemiAnalysis as a Visiting Fellow and spends $10,000 over three hours to discover dozens of bugs in AMDGPU LLVM, x86 LLVM, and NVPTX compiler backends through automated fuzzing.
Extraction
Topics: compiler-fuzzinggpu-compilersllvmamdgpunvptx
Claims
- Justin Lebar, former OpenAI tech lead, has joined SemiAnalysis as a Visiting Fellow.
- A single $10,000 fuzzing run lasting approximately three hours surfaced dozens of bugs across GPU and CPU compiler backends.
- Compiler fuzzing is an underutilized method capable of systematically finding bugs in AMDGPU LLVM, x86 LLVM, and NVPTX backends.
Key quotes
Burn $10,000 in 3 hours to find dozens of AMDGPU LLVM, x86 LLVM, NVPTX bugs