message: preprocess: also consider non-zero GEPs for removal
diff: @@ -922,6 +922,7 @@ static map<string_view, Instr*> can_remove_init(Function &fn) {
  if (user == gvar ||
  isNoOp(*user) ||
  + dynamic_cast<GEP*>(user) ||
  dynamic_cast<Phi*>(user) ||
  dynamic_cast<Select*>(user)) {
  for (auto p = users.equal_range(user); p.first != p.second; ++p.first)
  