Christian Ulmann
Senior Compiler Engineer at NextSilicon
Zurich, Zurich, United States
Summary
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Top SchoolChristian Ulmann is a Senior Compiler Engineer based in Zurich with a decade of experience designing and implementing compiler infrastructure and programming abstractions. He has deep, practical expertise across IR design, compiler transformations, static analysis, lowerings, DSLs, and hardware abstractions, honed through active contributions to high-profile open-source projects such as LLVM and CIRCT. His work on LLVM’s Mem2Reg pass, alias analysis in the inliner, and IR refactorings directly improved optimization and code generation, while contributions to CIRCT advanced HandshakeToFIRRTL lowering, tuple support, and buffer/cycle handling for hardware compilation. At NextSilicon he progressed from software engineer to senior compiler engineer, bringing research-grade knowledge from an MS in Computer Science at ETH Zürich into production compiler and hardware toolflows. Colleagues value him for bridging academic rigor and pragmatic engineering—he’s as comfortable prototyping IR design as shipping robust backend transformations.
10 years of coding experience
3 years of employment as a software developer
Matura, Matura at BME NeufeldMaster of Science - MS Computer Science, Master of Science - MS Computer Science at ETH ZürichInformatiker EFZ Applikationsentwicklung, Informatiker EFZ Applikationsentwicklung at BITTechnische Berufsmaturität, Technische Berufsmaturität at gibb Berufsfachschule Bern
German, English, French
Stackoverflow
5,740reputation
412kreached
93answers
7questions
angular
top-1%
rxjs
top-5%
typescript
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unit-testing
top-5%
Github Skills (23)
typescript10
firrtl10
mlr10
inlining10
angular-service10
compiler-optimization10
llvm-ir10
angular10
c-language9
unit-testing9
rxjs9
cprogramming-language9
verilog8
jasmine6
linter6
Programming languages (10)
Github contributions (5)
llvm/llvm-project
Jan 2023 - Jan 2023
The LLVM Project is a collection of modular and reusable compiler and toolchain technologies.
Role in this project:
Back-end Developer
Back-end DeveloperContributions:427 reviews, 4 commits, 191 PRs in 5 days
Contributions summary:Christian's contributions primarily focused on enhancements and modifications to the LLVM IR dialect within the LLVM project. They implemented changes to the Mem2Reg pass, enhancing its capabilities related to partial loads and stores, and also worked on improvements to the alias analysis infrastructure within the inliner. Their work also included refactoring and removing outdated features and the integration of new features within the LLVM IR. This user's modifications directly impact the compiler's optimization and code generation stages.
compilerllvmtoolchain
llvm/circt
Mar 2022 - Nov 2022
Circuit IR Compilers and Tools
Role in this project:Back-end Developer
Back-end DeveloperContributions:147 reviews, 61 commits, 114 PRs in 8 months
Contributions summary:Christian primarily contributed to enhancing the HandshakeToFIRRTL conversion process. They added support for tuple types, and also implemented lowerings for `PackOp`, `UnpackOp` and the `SyncOp`. Additional work included improving buffer initialization and cycle detection, alongside fixing issues related to external functions and the mux input order.
compilercirctllvmmlir
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