message: Adds sigmoid to the list of operations that can be recomputed.
diff: @@ -47,12 +47,11 @@ const char* kRecomputeHint = "_recompute_hint";
  // TODO(allenl): Replace this list with a cost model.
  std::unordered_set<string> GetCheapToRecomputeOps() {
  std::unordered_set<string> cheap_ops = {
  - "Add", "AddN", "BiasAdd", "Cast",
  - "Fill", "FloorDiv", "FloorMod", "FusedBatchNorm",
  - "Mul", "Neg", "RealDiv", "Reciprocal",
  - "Relu", "Relu6", "Reshape", "Rsqrt",
  - "Sqrt", "Square", "SquaredDifference", "Sub",
  - "Tile", "Transpose"};
  + "Add", "AddN", "BiasAdd", "Cast", "Fill",
  + "FloorDiv", "FloorMod", "FusedBatchNorm", "Mul", "Neg",
  + "RealDiv", "Reciprocal", "Relu", "Relu6", "Reshape",
  + "Rsqrt", "Sigmoid", "Sqrt", "Square", "SquaredDifference",
  + "Sub", "Tile", "Transpose"};
  return cheap_ops;
  }
  