Re: any chance of 2.6.0-test*?

Albert D. Cahalan
2003-01-13T22:31:16Z

Matti Aarnio writes:

> Advanced optimizer hinting features, like unlikely() attribute
> are very new in (this) compiler, and while they in theory move the
> "unlikely" codes out of the fast-path, such things have been buggy
> in the past, and we are worried of bug effects...

I've been wondering about this as the goto-thread spewed by.

As I recall, gcc recently started moving basic blocks around.
This destroyed most of the careful goto-based optimizations.
Now we're supposed to use likely() and unlikely() instead.

Hmmm?

BTW, what I'd like is a way to change optimization settings
on a per-function or even per-block basis. Telling gcc to
unroll a specific loop or pack a function into a tiny space
would be really cool. __attribute__((__opt__("-Os")))
I could go for an "assume default case can't happen" too.