*   Fixes an FPE in TFLite pooling operations
    ([CVE-2021-37684](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-37684))
*   Fixes an infinite loop in TFLite
    ([CVE-2021-37686](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-37686))
*   Fixes a heap OOB in TFLite
    ([CVE-2021-37685](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-37685))

        in_grads.push_back(zero);
      } else {
        in_grads.push_back(nullptr);
      }
    } else {
      in_grads.push_back(current_grad->second);
    }
  }

  // Avoid infinite recursion. Whichever forward function we run, it'll end up
  // executing ops, and we don't want to watch those with this accumulator.
  call_state_.emplace(nullptr, true);