Refinement of Parallel Algorithms down to LLVM

We present a stepwise refinement approach to develop verified parallel algorithms, down to efficient LLVM code. The resulting algorithms\u27 performance is competitive with their counterparts implemented in C/C++. Our approach is backwards compatible with the Isabelle Refinement Framework, such that existing sequential formalizations can easily be adapted or re-used. As case study, we verify a parallel quicksort algorithm, and show that it performs on par with its C++ implementation, and is competitive to state-of-the-art parallel sorting algorithms