[Bug tree-optimization/58195] Missed optimization opportunity when returning a conditional

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58195

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |missed-optimization
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2014-03-11
          Component|rtl-optimization            |tree-optimization
     Ever confirmed|0                           |1
      Known to fail|                            |4.9.0

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
phiopt should notice

  <bb 2>:
  if (input_2(D) != 0)
    goto <bb 3>;
  else
    goto <bb 4>;

  <bb 3>:
  iftmp.0_3 = -input_2(D);

  <bb 4>:
  # iftmp.0_1 = PHI <iftmp.0_3(3), 0(2)>

and value-replace iftmp.0_1 by -input_2(D).