Compilers have had detailed pipeline and memory hierarchy models available for decades. This is not a new thing in LLVM, the new thing is a language for describ

Compilers have had detailed pipeline and memory hierarchy models available for decades. This is not a new thing in LLVM, the new thing is a language for describing a pipeline (which replaces an older description language). Instruction generation and scheduling optimizations primarily. I don't know if much higher level optimization is done, possibly some cache blocking? I don't think the limitation is the hardware description available so much as actually using that to make worthwhile optimizations.