AVX / NEON Intrinsic Functions: When Should They Be Used?

Abstract: A cross-configuration benchmark is proposed to explore the capacities and limitations of AVX / NEON intrinsic functions in a generic context of development project, when a vectorisation strategy is required to optimise the code. The main aim is to guide developers to choose when using intrinsic functions, depending on the OS, architecture and/or available compiler. Intrinsic functions were observed highly efficient in conditional branching, with intrinsic version execution time reaching around 5% of plain code execution time. However, intrinsic functions were observed as unnecessary in many cases, as the compilers already well auto-vectorise the code.