message: Update batchnorm_expander.cc
diff: @@ -517,7 +517,7 @@ Status BatchNormExpanderVisitor::HandleBatchNormGrad(
  activation_shape, HloOpcode::kSubtract, activation, mean_broadcasted);
  // Grad[Y] * (X - E[X]).
  - auto grad_output_times_activiation_minus_mean =
  + auto grad_output_times_activation_minus_mean =
  add_binary(activation_shape, HloOpcode::kMultiply, grad_output,
  activation_minus_mean);
  @@ -525,9 +525,9 @@ Status BatchNormExpanderVisitor::HandleBatchNormGrad(
  GetOrCreateScalarAddComputation(ptype);
  // sum(Grad[Y] * (X - E[X])).
  - auto sum_grad_output_times_activiation_minus_mean =
  + auto sum_grad_output_times_activation_minus_mean =
  add(HloInstruction::CreateReduce(
  - feature_shape, grad_output_times_activiation_minus_mean, zero,
  + feature_shape, grad_output_times_activation_minus_mean, zero,
  dimensions_without_feature, add_reduce_computation));
  // Grad[beta] = Sum(Grad[Y]).
  @@ -537,7 +537,7 @@ Status BatchNormExpanderVisitor::HandleBatchNormGrad(
  // Grad[scale] = Sum(Grad[Y] * (X - E[X]) * rsqrt[Var[X] + epsilon]).
  auto grad_scale = add_binary(feature_shape, HloOpcode::kMultiply,
  - sum_grad_output_times_activiation_minus_mean,
  + sum_grad_output_times_activation_minus_mean,
  rsqrt_var_add_epsilon);
  // I2 = Sum(Grad[Y])
  @@ -546,7 +546,7 @@ Status BatchNormExpanderVisitor::HandleBatchNormGrad(
  // I3 = Sum(Grad[Y] * (X - E[X]))
  auto i3 = add(HloInstruction::CreateBroadcast(
  - activation_shape, sum_grad_output_times_activiation_minus_mean,
  + activation_shape, sum_grad_output_times_activation_minus_mean,
  {feature_index}));
  // I4 = (X - E[X]) * I3
  