auto def_op = operand.getDefiningOp();
      if (consumed_ops.contains(def_op)) continue;
      queue.push_back(def_op);
      consumed_ops.insert(def_op);
    }
  }
}

inline bool IsConstant(Operation *op) { return matchPattern(op, m_Constant()); }

bool AllOperationSafe(Block &block) {
  auto walk_result = block.walk([&](Operation *op) {
    // op has SideEffect.

  Output enter = ops::internal::Enter(
      root.WithOpName("enter"),
      ops::Placeholder(root.WithOpName("data"), DT_FLOAT), "frame_name",
      ops::internal::Enter::Attrs{}.IsConstant(true));
  EXPECT_THAT(enter.node(), NodeWith(Attr("is_constant", true)));
  EXPECT_EQ(Explain(enter.node(), NodeWith(Attr("is_constant", false))),
            "attribute named is_constant does not match value; expected: "

    operation
    ([CVE-2022-23587](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-23587))
*   Fixes a null pointer dereference in Grappler's `IsConstant`
    ([CVE-2022-23589](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-23589))
*   Fixes a `CHECK` failure in constant folding
    ([CVE-2021-41197](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-41197))