https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120003
--- Comment #4 from Andrew Macleod <amacleod at redhat dot com> ---
This seems to be the issue?
<bb 4> [local count: 350791453]:
_1 = g (i_3);
if (_1 != 0)
goto <bb 5>; [50.00%]
else
goto <bb 6>; [50.00%]
<bb 5> [local count: 175395727]:
<bb 6> [local count: 1063004408]:
# iftmp.0_4 = PHI <1(3), 0(4), 1(5)>
That 3 way PHI isn't used in any threads, so we don't get a threaded path to
the eventual return of 1.
