Joel Denny
Computer Scientist at Oak Ridge National Laboratory
Knoxville, Tennessee, United States
Summary
🤩
Rockstar🎓
Top SchoolJoel Denny is a computer scientist with eight years of professional experience in compiler design and implementation, currently working at Oak Ridge National Laboratory's Programming Systems Group. He has a deep open-source pedigree—co-maintaining GNU Bison and contributing substantive backend fixes to the widely used LLVM/Clang codebase, including LTO, OpenMP, and attribute handling improvements. Joel’s work blends low-level compiler internals (alias analysis, pass options, plugin loading) with practical engineering like build systems, source-to-source translation, and code formatting, honed earlier while developing the parallel SCALE language and SWARM runtime. His career spans research and production roles, bridging academic rigor from Clemson and the University of Tennessee with hands-on HPC toolchain delivery at ORNL and ETI. Colleagues rely on him for diagnosing subtle compiler bugs and improving long-lived toolchains, and he brings an unusual combination of parser theory (Bison algorithms) and large-scale compiler engineering to performance-critical systems.
8 years of coding experience
16 years of employment as a software developer
Doctor of Philosophy (Ph.D.), Computer Science, Doctor of Philosophy (Ph.D.), Computer Science at Clemson University
Github Skills (12)
compiler10
openmp10
attribute10
compiler-design10
compiler-compiler10
c-language10
coding-style10
clangd10
cprogramming-language10
clang10
llvm10
flang9
Programming languages (9)
Github contributions (5)
llvm/llvm-project
Oct 2019 - Mar 2025
The LLVM Project is a collection of modular and reusable compiler and toolchain technologies.
Role in this project:
Back-end Developer
Back-end DeveloperContributions:191 reviews, 42 PRs, 104 pushes in 5 years 5 months
Contributions summary:Joel primarily contributed to improving the LLVM compiler infrastructure, specifically focusing on the LTO (Link Time Optimization) and OpenMP components. Their work includes addressing plugin loading failures, extending the clang-linker-wrapper to include pass options, and fixing build and test issues. The user also made changes to the flang alias analysis, improving its logic for handling pointers and memory operations.
compilerstechnologiesclangsubmittoolchain
llvm-mirror/clang
Feb 2018 - Aug 2019
Mirror kept for legacy. Moved to https://github.com/llvm/llvm-project
Role in this project:Backend Developer
Backend DeveloperContributions:39 commits in 1 year 6 months
Contributions summary:Joel's commits primarily focus on modifications within the Clang compiler, specifically related to attribute handling and code formatting. The contributions include fixing parameter indexing issues for attributes, addressing bugs in attribute diagnostics, and improving the printing of enum attributes. The user also made changes to the handling of OpenMP directives, revealing involvement in compiler features related to parallel computing. Furthermore, the commits indicate a focus on code style and formatting, improving the codebase's readability.
keptwindowsllvmcc-plus-plus
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