https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122837
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
See Also| |https://gcc.gnu.org/bugzill
| |a/show_bug.cgi?id=67962,
| |https://gcc.gnu.org/bugzill
| |a/show_bug.cgi?id=80874
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #1)
> <bb 2> [local count: 1073741824]:
> if (a_2(D) > b_3(D))
> goto <bb 4>; [50.00%]
> else
> goto <bb 3>; [50.00%]
>
> <bb 3> [local count: 536870912]:
>
> <bb 4> [local count: 1073741824]:
> # __m_7 = PHI <a_2(D)(3), b_3(D)(2)>
> # __M_6 = PHI <b_3(D)(3), a_2(D)(2)>
> # prephitmp_17 = PHI <1(3), 18446744073709551615(2)>
> _8 = __M_6 - __m_7;
> _9 = _8 >> 1;
> _10 = _9 * prephitmp_17;
> _11 = a_2(D) + _10;
> return _11;
>
> so we miss max/min detection and a > b ? 1 : -1 is not if-converted either.
>
> But possibly the whole thing needs to be pattern-matched?
The min/max issue is PR 67962 and PR 80874 .
The 1/-1 thing could be rewritten as:
_100 = PHI <0(3), 1(2)>
_101 = - _9;
_10 = _100 ? _101 : _9;
(if there is negcc optab for that type; or maybe just movcc)
And then that should be convert into:
_100 = a_2(D) > b_3(D);
_10 = _100 ? _101 : _9;
And I think combined that with the min/max it would just work.
