[Bug tree-optimization/42195] New: missed xnor optimization.

[Bug tree-optimization/42195] New: missed xnor optimization.

[pluto at agmk dot net]

bool xnor_1( bool x, bool y ) { return !( x ^ y ); }
bool xnor_2( bool x, bool y ) { return ( x && y ) || ( !x && !y ); }

both functions should emit (x==y) code, but _2 isn't optimized.

bool xnor_1(bool, bool) (x, y)
{
  int D.2085;
<bb 0>:
  return x == y;
}

bool xnor_2(bool, bool) (x, y)
{
  bool D.2181;
  int prephitmp.51;
  bool D.2098;
  bool D.2097;
  bool D.2096;
  bool iftmp.0;
  int D.2090;
<bb 0>:
  if (x == 0) goto <L2>; else goto <L0>;
<L0>:;
  (void) 0;
  prephitmp.51 = (int) y;
  goto <bb 3> (<L5>);
<L2>:;
  (void) 0;
  prephitmp.51 = (int) (y == 0);
<L5>:;
  return prephitmp.51;
}


-- 
           Summary: missed xnor optimization.
           Product: gcc
           Version: 4.4.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: pluto at agmk dot net
  GCC host triplet: x86_64-gnu-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42195

[Bug tree-optimization/42195] missed xnor optimization.

[rguenth at gcc dot gnu dot org]

------- Comment #1 from rguenth at gcc dot gnu dot org  2009-11-27 15:07 -------
Confirmed.  This somehow looks like a variant of PR42117.  Or of course a
missed folding - though I believe we shouldn't match this big patterns in fold
anymore.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  BugsThisDependsOn|                            |42117
           Severity|normal                      |enhancement
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
      Known to fail|                            |4.5.0
   Last reconfirmed|0000-00-00 00:00:00         |2009-11-27 15:07:29
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42195

[Bug tree-optimization/42195] missed xnor optimization.

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42195

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=80588
             Status|ASSIGNED                    |RESOLVED
   Target Milestone|---                         |13.0
         Resolution|---                         |FIXED

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Fixed for GCC 13 by r13-1779-g375668e0508 .

[Bug tree-optimization/42195] missed xnor optimization.

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42195

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
           Assignee|unassigned at gcc dot gnu.org      |pinskia at gcc dot gnu.org

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Mine.