GCC 4.6

[Iain Buclaw]

== Quote from bearophile (bearophileHUGS at lycos.com)'s article
> Walter:
> > You quoted a claim saying it was also an optimization.
> If GCC devs say so, then I presume they are right. But the main purpose of a
warning is to warn the programmer, in this case to avoid some bugs.

Warnings have no effect on optimisations. And unused code are later removed via
general dead code elimination anyway (how aggressive this is depends on the
optimisation level).