Sure, making a dynamic language fast is not easy. However, back then people thought LLVM was a magic wand. It wasn't. There were several problems. First, the U

Sure, making a dynamic language fast is not easy. However, back then people thought LLVM was a magic wand. It wasn't. There were several problems. First, the Unladen Swallow team (IIRC) spent a lot of time fixing bugs in LLVM. Second, LLVM isn't fast at compiling code, at least not for a JIT. This is legitimately surprising, because the official LLVM Tutorial implements a JIT. Third, LLVM used to stand for Low Level Virtual Machine. I don't know when it stopped standing for that; clearly it hasn't for a long time. But with “Virtual Machine” in the title, you can see why people might have thought it would be suitable for implementing a dynamic language. cf. GraalVM these days.