LLVM IR

LLVM IR is a strictly typed, RISC-like intermediate language that serves as the universal bridge between high-level source code and machine-specific binary instructions.

This Static Single Assignment (SSA) based representation acts as the core interface for the LLVM compiler infrastructure. It utilizes a language-independent instruction set (including operations like `phi`, `getelementptr`, and `icmp`) to facilitate sophisticated middle-end optimizations. By standardizing the communication between front-ends like Clang or Rust and back-ends for x86, ARM, or RISC-V, LLVM IR ensures that a single optimization pass benefits multiple architectures. The format exists in three interchangeable forms: an in-memory C++ object model, a compact bitcode file (.bc), and a human-readable assembly text (.ll).

https://llvm.org/docs/LangRef.html