message: Make HLO device placer more stable as far as created partitions goes.
  Also remove the multi-module input capability for the device placer.
diff: @@ -25,6 +25,7 @@ limitations under the License.
  #include <iosfwd>
  #include <list>
  #include <memory>
  +#include <set>
  #include <string>
  #include <tuple>
  #include <unordered_map>
  @@ -1451,6 +1452,10 @@ template <typename ValueT>
  using ConstHloInstructionMap =
  std::map<const HloInstruction*, ValueT, HloPtrComparator>;
  +using HloInstructionSet = std::set<HloInstruction*, HloPtrComparator>;
  +using ConstHloInstructionSet =
  + std::set<const HloInstruction*, HloPtrComparator>;
  +
  } // namespace xla
  #endif // TENSORFLOW_COMPILER_XLA_SERVICE_HLO_INSTRUCTION_H_
  