Here's how the LLVM-based Neu Framework is described by its authors:
Neu (pronounced "new") is a C++ 11 framework, collection of programming languages, and multipurpose software system designed for: the creation of artificial intelligence applications and systems, modeling and simulation, programming language and compiler construction, technical computing in general, and more. Neu's primary design motivations are: elegance and simplicity achieved through good design, and developer convenience/productivity while at the same time aiming for the highest performance possible. Neu is made available as open source under a minimally-restrictive BSD-style license and can be used freely in commercial applications. Neu was designed for UNIX-based systems and compiles and runs on Mac OS X and Linux and is expected to be easily ported to other systems as well. The Neu codebase consists of highly reusable and well-integrated components, providing a clean and well-refined design and implementation which is easy to read, use, and modify/extend.
Neu features a large range of functionality including: powerful datatypes, most importantly nvar, a recursive variant type capable of representing virtually any type of data, including nested and symbolic data, in a highly efficient manner; easy program setup including configuration and options handling; powerful language design features which were used to create NML - an interpreted language with functional programming aspects, NPL - a high-performance concurrent language using LLVM JIT compilation; a task and graph-based concurrency system; networking and distributed objects; Meta Concepts: A Knowledge-Based Code Generation System; high performance neural networks using LLVM/JIT; several utility classes, and more.
It sounds interesting and it's also yet another interesting use-case of LLVM and Clang. Those wishing to find out more about the BSD-licensed Neu Framework can visit its project site Andrometa.net.