Your parent already addresses this: > This, however, doesn't apply to the code generation phase with LLVM which is already parallelizable at the codegen unit l

Your parent already addresses this: > This, however, doesn't apply to the code generation phase with LLVM which is already parallelizable at the codegen unit level (the number of codegen units is configurable), but that's the “back-end”, whereas this new parallelization applies to the “front-end” of the compiler.