message: [XLA] Add TODO comment explaining why the IsScalar check exists.
diff: @@ -41,6 +41,11 @@ StatusOr<bool> ReducePrecisionInsertion::Run(HloModule* module) {
  // equivalent behavior can be obtained by adding ReducePrecision
  // instructions after the instructions that pull the F32 arrays out of
  // the tuples.
  + //
  + // TODO(b/64093391): Remove the IsScalar check once this won't cause
  + // failures on the GPU backend if the ReducePrecision instruction ends up
  + // inserted between a scalar constant and the init_value argument of a
  + // Reduce operation.
  if (instruction->shape().element_type() == PrimitiveType::F32 &&
  !ShapeUtil::IsScalar(instruction->shape()) &&
  should_reduce_output_precision_(instruction->opcode())) {
  