https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85301
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |law at gcc dot gnu.org
--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
That is, jump-threading fails to do
if (x & 3)
...
else
thread -->
if (x & 1)
...
else
<--- here
with the extra complication of that clobbering ktime_get () call on the
true path and x being memory references where DOM sees it. PRE "cleans"
that up on the interesting path but still late DOM doesn't perform the
threading:
<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 4>; [67.00%]
<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)(2)>
# prephitmp_15 = PHI <pretmp_14(3), _1(2)>
_4 = prephitmp_15 & 1;
if (_4 != 0)
goto <bb 5>; [33.00%]
else
else
goto <bb 6>; [67.00%]
<bb 5> [local count: 354334802]:
__tick_nohz_idle_restart_tick (now_5);
<bb 6> [local count: 1073741825]:
