Philippe Gerum authored Dec 04, 2020 and Jan Kiszka committed Dec 11, 2020

In user-space at least, we'd be better off trusting the CPU's branch
predictor, instead of relying on our limited perception when it comes
to determining the likeliness of a condition, or every compiler to do
the right thing with respect to efficient branching.

We only have a few unlikely predictions in-tree on straightforward
conditions, which we can remove safely:

- POSIX condvars wait/signal loops on x86, arm and arm64 showed no
  observable performance penalty.

- other callers from the thread cancellation path, or debug
  instrumentation are slow paths in essence anyway.

Signed-off-by: Philippe Gerum <rpm@xenomai.org>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>