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Azul is seeking a Compiler Performance Engineer to optimize Falcon, the just-in-time (JIT) compiler in Azul Platform Prime. Falcon compiles hot Java bytecode into highly optimized machine code and is built on LLVM. This is not a greenfield compiler role—Falcon is production-deployed at large enterprises—but rather a performance optimization position focused on identifying and eliminating inefficiencies in generated code.
You will join a distributed team of compiler experts and work on real customer workloads with direct, measurable impact on performance. Your work will span the full optimization pipeline: middle-end and back-end optimizations (inlining, loop transformations, vectorization, redundancy elimination, speculative optimizations), code generation for x86_64 and AArch64 architectures, and upstream contributions to LLVM where applicable.
Key responsibilities include:
- Analyzing performance of Java benchmarks and customer workloads to identify gaps in generated code and trace root causes in the compiler
- Implementing and improving optimizations in Falcon's middle end and back end
- Enhancing code generation for x86_64 and AArch64 targets
- Writing tests and benchmarks to validate improvements and prevent regressions
- Contributing improvements upstream to LLVM where appropriate
This role is ideal for someone with deep compiler expertise who enjoys hands-on performance tuning and wants to see direct customer impact from their optimizations.
Requirements:
- 2+ years of professional experience in compilers, JIT compilers, or low-level performance engineering
- Strong C++ design and coding skills
- Solid understanding of compiler optimization theory: SSA, data flow analysis, loop transformations
- Ability to read assembly and reason about instruction-level performance trade-offs
Nice to have:
- Experience with LLVM IR and LLVM optimization passes, or other optimizing compilers (HotSpot C2, Graal, GCC, V8)
- Profiler experience (perf, VTune, async profiler)
- Knowledge of x86_64 and/or AArch64 microarchitecture
- Experience with Java, Scala, Kotlin, or JVM internals
- MSc or PhD in Computer Science with compiler or performance focus
