If you were not aware of this then you might reflect on the part of my comment that he doesn’t bring up: how good/bad are use-case dependent. Every program optimizes for a use case, sometimes pessimizing for others (e.g. an n^2 algo that’s worthwhile because it is believed to only be called on tiny vectors).

IMHO he was overgenerous on the optimization improvement of compilers. Often an optimization will make a difference in a tiny fraction of a percent. The value comes from how often that optimization can be applied, and how lots of optimizations can in aggregate make a bigger improvement just as a sand dune is made of tiny grains of sand.