LLVM (in ORC mode) is very powerful. I wrote a JIT compiler for a DSL with it. It takes a fair bit of poring over the IR manual to figure out basic things. The

LLVM (in ORC mode) is very powerful. I wrote a JIT compiler for a DSL with it. It takes a fair bit of poring over the IR manual to figure out basic things. The optimization is as good as for C, including automatic unrolling of loops to generate SIMD instructions. A very useful feature is that you can write C or C++ and run it through LLVM to see the IR it generates, and adapt it to your needs. You can even do it in Godbolt. If your generated code is crunching over large amounts of data, an alternative to a JIT is to make the interpreter implicitly parallel. So each interpreter dispatch operation does N (say, 16) parallel operations, effectively cutting interpreter overhead by N. It works if there isn't data-dependent branching, which is often true for numerical operations.