Jon Chesterfield
Software Engineer at Spectral Compute
Bristol, England, United Kingdom
Summary
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Rockstar🎓
Top SchoolJon Chesterfield is a software engineer with 11 years' experience specializing in compiler and GPU toolchain work, currently advancing ROCm and GPU compiler capabilities at Spectral Compute after a six-year stint at AMD. He has deep backend expertise in LLVM—fixing verifier bugs, handling AArch64 stack alignment, and implementing zero-cost variadic support for AMDGPU—helping make high-performance GPU compute more accessible. Based in Bristol, Jon combines practical systems engineering from Graphcore and SN Systems with research roots from the University of Bath, and he’s known for quietly solving thorny ABI and va_list issues that others sidestep. Not available for hire but open to consulting, he offers pragmatic ways to reduce Nvidia compute spend by making ROCm work reliably.
11 years of coding experience
12 years of employment as a software developer
Master of Engineering (MEng), Mechanical Engineering, Master of Engineering (MEng), Mechanical Engineering at University of Bath
English
Stackoverflow
2,323reputation
201kreached
37answers
36questions
Github Skills (12)
compiler-optimization10
c-language10
backend10
cprogramming-language10
back-end-development10
llvm10
amdgpu9
arm9
spirv8
linux6
warnings6
gcc6
Programming languages (9)
Github contributions (5)
llvm/llvm-project
Sep 2021 - Jan 2023
The LLVM Project is a collection of modular and reusable compiler and toolchain technologies.
Role in this project:
Backend Developer
Backend DeveloperContributions:198 reviews, 7 commits, 52 PRs in 1 year 4 months
Contributions summary:Jon's contributions primarily involve modifying and maintaining the LLVM project's compiler infrastructure, specifically the verifier. They fixed a bug related to `va_start` usage in non-variadic functions, then reverted and reapplied the fix. The user also addressed stack alignment issues in the AArch64 architecture related to variable argument handling. Furthermore, the user worked on AMDGPU backend, implementing variadic function support, making them zero cost abstraction.
compilerllvmtoolchain
ROCm/amd-llvm-project
Mar 2020 - Dec 2020
DO NOT USE : Deprecated : Mirror of AMD llvm-project : The source repo is https://github.com/RadeonOpenCompute/llvm-project. Several times a day the default branch "amd-stg-open" is updated from the source repo and then locked. The purpose of this repo is to share and test fixes that have not yet gone into a review process.
Contributions:19 reviews, 170 commits, 229 PRs in 8 months
amdllvm
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