[Bug middle-end/38209] branch optimisation generates worse code

[pinskia at gcc dot gnu dot org]

------- Comment #2 from pinskia at gcc dot gnu dot org  2008-11-23 18:55 -------
This happens on i386-darwin also (-m64 -O2 -fomit-frame-pointer):
        movl    %edi, %edx
        testb   %dil, %dil
        movl    $-1, %eax
        notl    %edx
        cmovne  %edx, %eax

Using the following source:
unsigned char negate(unsigned char val)
{
    if (val)
        val = ~val;
    else
        val = ~val;
  return val;
}

We should be able to just do ~val but this comes down to hoisting before
applying VRP/DOM.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
  GCC build triplet|i386-linux-gnu              |
   GCC host triplet|i386-linux-gnu              |
 GCC target triplet|avr-*-*                     |
   Last reconfirmed|0000-00-00 00:00:00         |2008-11-23 18:55:59
               date|                            |
            Summary|[avr] branch optimisation   |branch optimisation
                   |generates worse code        |generates worse code


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38209