Compiler Performance Engineer (Java/LLVM)

Location: Prague, Belgrade, Serbia (remote), Cyprus (remote), Limassol, Toronto, or Canada (remote); remote-first, office-based, or hybrid arrangements are available.

Company

hirify.global develops the Java platform for modern cloud enterprises, including the LLVM-based Falcon JIT compiler in hirify.global Platform Prime.

What you will do

• Analyze Java benchmarks and customer workloads to identify gaps in generated code and trace performance issues to compiler root causes.
• Implement and improve Falcon middle-end and back-end optimizations, including inlining, loop optimizations, vectorization, redundancy elimination, and speculative optimizations.
• Improve code generation for x86_64 and AArch64 and optimize interaction with the runtime.
• Write tests and benchmarks to demonstrate improvements and prevent regressions.
• Contribute relevant changes upstream to LLVM.

Requirements

• At least 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, including SSA, data-flow analysis, and loop transformations.
• Ability to read assembly and explain why one instruction sequence is faster than another.

Nice to have

• Experience with LLVM IR and LLVM optimization passes, or another optimizing compiler such as HotSpot C2, Graal, GCC, or V8.
• Experience with profilers such as perf, VTune, or async profiler.
• Knowledge of x86_64 and/or AArch64 microarchitecture.
• Experience with Java, Scala, or Kotlin, or with JVM internals.
• MSc or PhD in Computer Science with a compiler or performance focus.

Culture & Benefits

• Work with distributed compiler experts and contribute to the Java and OpenJDK ecosystem.
• Opportunity to make a measurable impact on customer performance at a growing global company.
• Remote-first work, Prague, Limassol, or Belgrade city-center offices, or a hybrid arrangement.
• Flexible working hours, paid holidays, and sick time.
• Premium IT equipment, including a MacBook Pro or hardware of choice.
• Referral program and competitive compensation.