Remembering Johannes Doerfert

Johannes Doerfert, a highly esteemed contributor to the LLVM compiler project, passed away on September 17, 2026, at the age of 36 following a battle with cancer. Born on November 5, 1989, Johannes earned his Ph.D. in computer science from Saarland University, Germany, in 2018, focusing on polyhedral compiler technologies for low-level code.

Since 2014, he had been an active contributor to LLVM, working under Prof. Sebastian Hack at the compiler design lab. In 2012, he became a core developer on the Polly polyhedral-optimization project. Over the course of his career, Johannes built a career at the intersection of compiler research and high-performance computing, with a focus on OpenMP, LLVM, and parallel program optimization.

His contributions to the LLVM Project included dozens of papers on compiler optimization, automatic differentiation of GPU kernels, performance portability, and OpenMP. Johannes also organized various events, such as EuroLLVM 2017 in Saarbrücken, Germany, and the LLVM-HPC workshop at CGO since 2017. He was frequently present at LLVM Developers’ Meetings, welcoming newcomers and providing advice on how to become more involved in the project.

Johannes also held weekly office hours, answering questions on a wide range of topics related to LLVM, OpenMP, LLVM-IR, interprocedural optimizations, and Attributor. He was frequently invited to speak at LLVM Developers’ Meetings, with 11 talks across 11 years (2015–2024). Known for his vibrant personality and a sense of humor, Johannes was remembered for his contributions to the LLVM Project, as well as his enthusiasm for life, humor, and the simple pleasures in life, such as drinking beer.

A memorial service will be held on October 3, 2026, in San Jose, California, with a separate service planned in Germany. In lieu of flowers, the family has asked for donations to the LLVM Foundation, with a generous donor agreeing to match 50K in donations.