Any way to do branch hints?

[Kean Johnston]

Hi everyone,

Does gcc have any way in which I can portably introduce
branch hints, and do any of the machine descriptions
(of most personal interest is i386.md) use them? What
I'd liket o be able to do is something like:
int myfunc (void)
{
 int x = foo();
 if (x == 0) __attribute__(branch-hint-not-taken)
   error();
 else {
   do_some_work();
 }
 return x;
}
Armed with such information it would be great if the
code generated for a conditional jump would actually
include the hint prefix to the insn. I couldn't find
anything in the 3.4 docs, so I am guessing it doesn't
exist, but I may just have grepped for the wrong
things.
Kean