message: [TF:XLA] Document that the order of control predecessors matters.
diff: @@ -1616,6 +1616,10 @@ class HloInstruction {
  InstructionVector operands_;
  // The set of control predecessors of this instruction.
  + // Note that the order of the instructions in the vector influences the order
  + // computed in HloComputation::ComputeInstructionPostOrder, which may
  + // influence the result of the compilation by changing the scheduling. We are
  + // not sure if it matters.
  std::vector<HloInstruction*> control_predecessors_;
  // The users of this instruction. Users are HLOs where this instruction is an
  