https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118468
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Ever confirmed|0 |1
Keywords| |missed-optimization
Status|UNCONFIRMED |NEW
Blocks| |53947
Last reconfirmed| |2025-01-14
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
That bb 12 isn't inside the loop. The issue is that if-conversion fails
to if-convert
<bb 3> [local count: 1044213920]: (loop header)
# s_15 = PHI <s_10(9), s_7(D)(8)>
_1 = *s_15;
if (_1 > 63)
goto <bb 11>; [50.00%]
else
goto <bb 4>; [50.00%]
<bb 11> [local count: 522106960]:
goto <bb 5>; [100.00%]
<bb 4> [local count: 522106960]:
_14 = (int) _1;
_17 = 9223372036854785024 >> _14;
_18 = _17 & 1;
_19 = _18 == 0;
_25 = ~_19;
<bb 5> [local count: 1044213920]:
# prephitmp_26 = PHI <_25(4), 0(11)>
because
"Can not ifcvt due to multiple exits"
that's a stop-gap to avoid spending time on if-converting that's useless
in the end. We also have
"basic block after exit bb but before latch"
so basically if-conversion doesn't know how to if-convert between
two exits - it always tries to remove _all_ control flow, not knowing
how to keep hands off of exit tests.
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53947
[Bug 53947] [meta-bug] vectorizer missed-optimizations
