http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58195
--- Comment #3 from Marc Glisse <glisse at gcc dot gnu.org> --- This looks like the unary version of: http://gcc.gnu.org/ml/gcc-patches/2014-03/msg00014.html and something that could be auto-generated from a pattern like: (cond (ne @0 0) (negate @0) 0) -> (negate @0) ;-)
