Optimisation; -On vs -f<something>

[Nix]

There seem to be a depressing number of optimisations (in gcc 2.7.2 at least)
that are controlled by the optimisation level directly rather than being
controlled by one of the flags that switching optimisation level; this stops
realistic tuning for speed vs size, for instance (and on the machine this was
being tested on, any major size increase translates into a massive speed
decrease due to increased paging).

Will this annoying state of affairs be the case in egcs as well?