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Re: [PATCH] powerpc: fix ifunc-sel.h with GCC 6
On Thu, 2016-07-21 at 17:23 +0200, Andreas Schwab wrote:
> Florian Weimer <fweimer@redhat.com> writes:
>
> >
> > Yes, I figured that out in the meantime. Is “bcl 20,31” always
> > used for
> > that? The second opcode argument doesn't really matter, after
> > all.
>
> It's what gcc uses. I don't know if there is any deeper meaning
> behind that particular encoding.
>
There is. It tells the CPU not to push the address onto the link
stack. Without this, you end up with an out of sync return stack
and so your subsequent real returns get mispredicted.
Cheers,
Ben.