Zirgen is a compiler for a domain-specific language, also called "zirgen", which creates arithmetic circuits for the RISC Zero proof system.
For the most part, users of RISC Zero should be writing their zkApps in Rust and using our RISC-V zkVM rather than building them directly in Zirgen. Sometimes, however, it is necessary or desirable to write parts of an application as an arithmetic circuit to integrate directly with our proof system and achieve better performance. In fact, we have an upcoming version of the zkVM circuit written in Zirgen! Zirgen will make it possible to build accelerators for important parts of your applications, or even to build entire other VMs that integrate into the RISC Zero ecosystem through proof composition. With that said, it's still a work in progress and has quite a few rough edges.
We also have an integration with Circom in the works -- this will make it possible to generate recursion circuit programs that verify witnesses for arbitrary Circom circuits. This can be found here.
graph TD;
A[Zirgen] --> B[Zirgen Compiler]
C[Circom] --> B
B --> D[Rust code]
B --> E[C++ code]
B --> F[Recursion VM predicates]
