The IR acts as an intermediary between the compiler's front-end (parsing and semantic analysis) and the back-end (machine-code optimizations and generation). Th

The IR acts as an intermediary between the compiler's front-end (parsing and semantic analysis) and the back-end (machine-code optimizations and generation). The independent IR makes it possible to reuse, say, a C-language front-end regardless of the targeted object code. Similarly, an x86 back-end can be reused with any programming language. Another nicety of a "high-level" IR vs machine code is that a lot of details become easier. LLVM has an infinite number of registers, and abstracts-out much of the calling convention.