Finding Reusable Instructions via E-Graph Anti-Unification

Domain-specific accelerators provide an increasingly valuable source of performance for diverse applications. Custom instructions that trigger the execution of dedicated hardware units or accelerators for common application functions become key building blocks in modern computing systems, balancing performance and cost effectiveness. RISC-V, the open and extensible instruction set architecture, is increasingly popularizing this trend. However, exploring custom instructions for an application domain remains challenging. Existing automated approaches suffer from poor reusability and limited performance. They can only identify or merge syntactically similar, scalar instruction sequences while missing semantically equivalent patterns.