Craig Topper
Principal Compiler Engineer at SiFive
Beaverton, Oregon, United States
Summary
🤩
Rockstar🎓
Top SchoolCraig Topper is a Principal Compiler Engineer with 17 years of experience, currently driving compiler and toolchain optimizations at SiFive from Beaverton, Oregon. He specializes in backend compiler work and ISA support, with notable contributions to high-profile open-source projects including LLVM and apple/swift-llvm where he optimized APInt bitwise operations and streamlined code footprint. His work on RISC-V support tackled floating-point edge cases (f16, i128), FMA codegen, and frame-index/memory-operand handling, reflecting deep pragmatic expertise in code generation and correctness. A Purdue Computer Science graduate, Craig pairs rigorous systems-level thinking with hands-on refactors that modernize legacy tooling and reduce binary size—an engineer who improves both performance and maintainability.
17 years of coding experience
Bachelor, Computer Science, Bachelor, Computer Science at Purdue University
Github Skills (27)
c-language10
bitwise10
llvm10
risc-v10
refactor10
compiler-optimization10
bit10
refactoring10
cprogramming-language10
optimization10
float329
assembly9
integer-arithmetic9
assemble9
assembler9
Programming languages (13)
Github contributions (5)
llvm/llvm-project
Mar 2022 - Jan 2023
The LLVM Project is a collection of modular and reusable compiler and toolchain technologies.
Role in this project:
Back-end Developer & Compiler Optimization Engineer
Back-end Developer & Compiler Optimization EngineerContributions:3931 reviews, 16 commits, 1783 PRs in 10 months
Contributions summary:Craig was responsible for contributing to the RISC-V instruction set architecture (ISA) project, specifically focusing on compiler and disassembler improvements. Their commits involved bug fixes and optimizations related to handling floating-point operations, particularly for f16 and i128 data types, including modifications to improve code generation related to FMA instructions and dealing with the Zfinx/Zdinx and Zhinx extensions. They also addressed memory management and potential code generation errors by improving the handling of frame index references, memory operand, and other related operations.
compilerstechnologiesclangsubmittoolchain
llvm-mirror/clang-tools-extra
Mar 2014 - Apr 2016
Mirror kept for legacy. Moved to https://github.com/llvm/llvm-project
Role in this project:Back-end Developer
Back-end DeveloperContributions:14 commits in 2 years 1 month
Contributions summary:Craig primarily focused on refactoring and modernizing the codebase, specifically within the clang-tools-extra repository which focuses on clang tooling. Their work included updating C++11 features by replacing LLVM_OVERRIDE and using 'nullptr', in addition to code simplification. Further contributions involved updates to the build process and the inclusion of colored output for diagnostics.
keptwindowsllvm
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