[Bug tree-optimization/81503] [8 Regression] Wrong code at -O2

[glisse at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81503

--- Comment #4 from Marc Glisse <glisse at gcc dot gnu.org> ---
  if (a + b * -2)
    c = (b-1073741824)*-2;

might let you find an earlier culprit.