[Bug c++/85799] __builin_expect doesn't propagate through inlined functions

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85799

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2018-05-16
                 CC|                            |hubicka at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
I believe inlining is happening too late for it to have an effect - we are
early inlining a body which has the __builtin_expect replaced by nothing.

Iff the expected outcome is "constant" a new function attribute would work.
For outcome dependent on context that wouldn't work.

Not sure if we can simply introduce a return-value predictor that survives
inlining?  Honza?