Why is llvm considered unsuitable for implementing a JIT?

Question

Many dynamic languages implement (or want to implement) a JIT Compiler in order to speed up their execution times. Inevitably, someone from the peanut gallery asks why they

Answer 1

There is a presentation on using LLVM as a JIT backened where the address many of the concerns raised as to why its bad, most of its seems to boil down to people building a static compiler as a JIT instead of building an actual JIT.