https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85301
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |jakub at gcc dot gnu.org
--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Maybe uninit just doesn't understand that in:
<bb 2> [local count: 1073741825]:
_1 = BIT_FIELD_REF <tick_nohz_idle_exit_ts, 8, 0>;
_2 = _1 & 3;
if (_2 != 0)
goto <bb 3>; [33.00%]
else
goto <bb 7>; [67.00%]
<bb 7> [local count: 719407025]:
goto <bb 4>; [100.00%]
<bb 3> [local count: 354334802]:
now_11 = ktime_get ();
pretmp_14 = BIT_FIELD_REF <tick_nohz_idle_exit_ts, 8, 0>;
<bb 4> [local count: 1073741825]:
# now_5 = PHI <now_11(3), now_9(D)(7)>
# prephitmp_15 = PHI <pretmp_14(3), _1(7)>
_4 = prephitmp_15 & 1;
if (_4 != 0)
goto <bb 5>; [33.00%]
else
goto <bb 8>; [67.00%]
<bb 8> [local count: 719407025]:
goto <bb 6>; [100.00%]
<bb 5> [local count: 354334802]:
__tick_nohz_idle_restart_tick (now_5); [tail call]
<bb 6> [local count: 1073741825]:
return;
if (_1 & 3) != 0 it implies (_1 & 1) != 0.
Though, if I change the testcase to:
void tick_nohz_idle_exit(void) {
long now;
struct tick_sched t = tick_nohz_idle_exit_ts;
if (t.idle_active || t.tick_stopped)
now = ktime_get();
if (t.tick_stopped)
__tick_nohz_idle_restart_tick(now);
}
so that it doesn't have to reread tick_nohz_idle_exit_ts.tick_stopped after the
ktime_get call, it doesn't warn anymore.
In that case now is always initialized though, so it shouldn't matter what
value we read for the uninit warning.
