LTO gets a lot of the way there, but it won't for example help with eliminating unused enums (and associated codepaths). That happens at per-crate MIR optimisa

LTO gets a lot of the way there, but it won't for example help with eliminating unused enums (and associated codepaths). That happens at per-crate MIR optimisation iirc, which is prior to llvm optimisation of LTO.