basic-block and profile-based optimizing (was Re: New attribute "infrequent"?)

[Jan Hubicka]

> This doesn't really matter, because the application itself presumabely
> will be going through profile-based optimization.. Thus, when profiling
I really don't expect this to hapend anytime soon.
Building distributions is really dificult task even now and using profile
feedback makes it even more dificult.  It is easy to do profile feedback
for gcc, where bootstrap can be just adjusted to have one training stage,
but imagine interactive programs, like gimp that should be fast too.

Some research on static prediction methods shows that they can do relativly
well (as shows our results too) and we really should take care to avoid
compiler from being depdendent on profile feedback, as it is dificult to
use for programmers/distribution builders.

Honza