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* [Bug tree-optimization/52409] New: ((~a)|(~b)) is not simplified at the tree level
@ 2012-02-28  7:13 pinskia at gcc dot gnu.org
  2012-02-28  7:16 ` [Bug tree-optimization/52409] " pinskia at gcc dot gnu.org
  0 siblings, 1 reply; 2+ messages in thread
From: pinskia at gcc dot gnu.org @ 2012-02-28  7:13 UTC (permalink / raw)
  To: gcc-bugs

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52409

             Bug #: 52409
           Summary: ((~a)|(~b)) is not simplified at the tree level
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: pinskia@gcc.gnu.org


Take:
int f(int a, int b)
{
  a = ~a;
  b = ~b;
  return a|b;
}

int g(int a, int b)
{
  return ~(a&b);
}
--- CUT ---
Currently the tree level does not try to combine them, fold does it though.  
I saw this with bools in GCC itself. In the bool case, we can fold it further
to just (a&b) == 0.  

Likewise for (~a)&(~b) into ~(a|b).


^ permalink raw reply	[flat|nested] 2+ messages in thread

* [Bug tree-optimization/52409] ((~a)|(~b)) is not simplified at the tree level
  2012-02-28  7:13 [Bug tree-optimization/52409] New: ((~a)|(~b)) is not simplified at the tree level pinskia at gcc dot gnu.org
@ 2012-02-28  7:16 ` pinskia at gcc dot gnu.org
  0 siblings, 0 replies; 2+ messages in thread
From: pinskia at gcc dot gnu.org @ 2012-02-28  7:16 UTC (permalink / raw)
  To: gcc-bugs

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52409

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |missed-optimization, TREE
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2012-02-28
         AssignedTo|unassigned at gcc dot       |pinskia at gcc dot gnu.org
                   |gnu.org                     |
     Ever Confirmed|0                           |1

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-02-28 07:13:35 UTC ---
Mine.


^ permalink raw reply	[flat|nested] 2+ messages in thread

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2012-02-28  7:13 [Bug tree-optimization/52409] New: ((~a)|(~b)) is not simplified at the tree level pinskia at gcc dot gnu.org
2012-02-28  7:16 ` [Bug tree-optimization/52409] " pinskia at gcc dot gnu.org

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