A compiler is often referred to be a mysterious piece of software. It takes a program written in a high-level language, applies dozens of transformations on it, and then spits out optimized machine code. It sounds like black magic. In this article, however, I would like to provide a counter argument by implementing a new dummy instruction in LLVM, and hopefully demonstrate how surprisingly straightforward it is if you know your way around. Here is our plan: add a new instruction to the RISC-V ta...