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.
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This archive was generated by hypermail 2b29 : Wed Jan 15 2003 - 22:00:47 EST