[Bug other/60486] [avr] missed optimization on detecting zero flag set

[darryl.piper at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60486

--- Comment #4 from Darryl Piper <darryl.piper at gmail dot com> ---
details also posted on avrfreaks.net

http://www.avrfreaks.net/index.php?name=PNphpBB2&file=viewtopic&p=1143389


the bug has existed since the code base copy from 4.7.2 to create the vanilla
4.8.0

so all the 4.8.[0,1,2] suffer this bug

namely these lines in avr_out_plus are the culprits IMO.

  /* Work out the shortest sequence.  */

  avr_out_plus_1 (op, &len_minus, MINUS, &cc_plus, code_sat, sign, out_label);
  avr_out_plus_1 (op, &len_plus, PLUS, &cc_minus, code_sat, sign, out_label); 

notice the &cc_plus and &cc_minus being the wrong way around.