Fix for __builtin_expect on PowerPC

[Jan Hubicka]

> > Can we handle conditional goto in same way, so we get predicted as unlikely?
> 
> I'm not sure what you mean by conditional goto, since do_jump handles
> conditional jumps.  Do you have a fragment of code to explain what you want
> predicted?
One predictor from my TODO list :)
Kernel folks often mention that sequences like
if (something)
   goto somewhere
are usually used by programmer to handle error situation (in the kernel it is
definitly common practice, I am not 100% sure that somewhere), but it can be
nice to have such constructs marked by predictor so we can evaulate that.

Having this heuristic in will make kernel folks happier, as gcc will not
reorder their curefully hacked code to have common path together in the
source.

Honza
> 
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> Michael Meissner, Red Hat, Inc.  (GCC group)
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