Senior Compiler Performance Engineer

About the role

Azul, a company focused entirely on Java, is looking for a Senior Compiler Performance Engineer to own major performance areas of Falcon, its optimizing JIT compiler built on LLVM. Falcon compiles hot Java bytecode into highly optimized machine code and runs in production at large enterprises. This is not a compiler front-end or built-from-scratch role: the job is to push the generated code further, choosing which optimizations matter, designing them and delivering measurable speedups on real workloads.

Key responsibilities

• Own Falcon for a set of workloads or an optimization area end to end: analysis, design, implementation and validation.
• Design and implement new optimizations and improve existing ones in the middle end and back end, including inlining heuristics, loop optimizations, vectorization, escape analysis, speculation and deoptimization, GC barrier and runtime call optimization.
• Drive code generation quality on x86_64 and AArch64, including bringing Falcon to new hardware platforms.
• Investigate complex performance issues reported by customers and turn findings into compiler improvements.
• Review code, mentor engineers on the team and raise the bar for performance methodology.

Required profile

• 5+ years of professional experience developing optimizing or JIT compilers.
• Proven track record of delivering compiler optimizations with measurable performance impact.
• Nice to have: PhD in Computer Science or significant research experience in compilers.

Required skills

• Strong C++ design and coding skills in large codebases.
• Deep knowledge of compiler optimization theory and its trade-offs: compile time, code size, correctness.
• Performance analysis skills: profilers, hardware counters, reading and reasoning about generated assembly.
• Nice to have: LLVM optimization passes or code generation, JIT compilers for managed languages (HotSpot C2, Graal, V8.NET RyuJIT), deep knowledge of x86_64 and/or AArch64 microarchitecture, JVM internals (garbage collection, deoptimization, profiling).

What we offer

• Opportunity to make a high impact at a growing, global company and work alongside top experts worldwide.
• Referral program and premium IT equipment (MacBook Pro or hardware of your choice).
• Competitive paid holidays and sick time, flexible working hours.
• Remote-first option, or city-center offices in Prague, Limassol or Belgrade, or hybrid.
• Competitive compensation.