Rust uses LLVM, a heavyweight backend with fearsomely thorough optimisation. It might be that for non-optimised output, the parser becomes the bottleneck again

Rust uses LLVM, a heavyweight backend with fearsomely thorough optimisation. It might be that for non-optimised output, the parser becomes the bottleneck again. Or it might be that LLVM just imposes overhead even for the unoptimised case, that pays for itself in the optimised case.