Remember, we're not talking about high performance C compilers and all that here. We're talking about the programming paradigm where everything is a compiler.

Remember, we're not talking about high performance C compilers and all that here. We're talking about the programming paradigm where everything is a compiler. Network protocol parsing is a form of compilation, all file formats parsing is a form of compilation, reacting to the UI events is a form of a compilation, processing data in whatever ways is a form of a compilation. Yet, you can only invent any optimisations at all for a small subset of compiler transformations, so for most of the cases optimisation is just totally irrelevant. As for the minimally acceptable optimisations, they're all trivial anyway. What you'd normally expect to see in most of the IRs is: constant propagation/folding (trivial), ADCE (trivial), algebraic simplification (trivial, no matter how ugly it is in, say, instcombine pass in LLVM - they're just doing it wrong), partial evaluation (trivial), inlining (trivial), backtracking for the latter two (trivial, but rarely seen, most would resort to awfully complex heuristics instead), CSE (trivial), escape analysis (trivial). What is not trivial is the stuff you'd rarely need in the high level languages, and this paradigm is all about the high level languages indeed. Not trivial: loop fusion, polyhedral analysis, vectorisation, and, finally, everything related to the code generation: instruction selection, register allocation, instruction scheduling, VLIW packing, all that. You'll never see this stuff in any high level domain specific language - you already have a common low level backend to take care of it for you anyway.