> Concatenation pretty much requires branches without unique characteristics, so no fast path

Discussion the other day, of optimizing dispatch overhead in no-jit-allowed lightweight-word vm's, raised a brainstormy idea of having multiple copies of some words, and the compiler juggling them with awareness of their tailcall-next-word varied branch predictor states. Sort of a dynamic version of reducing dispatch by identifying hot phrases and creating multi-word-composite new words for them.