<< "Cannot find function " << sym.getRootReference();
    }
    callees.push_back(callee);
  }
  return success();
}

bool HasSingleBlock(func::FuncOp func) {
  return func->getNumRegions() == 1 && func.getBody().hasOneBlock();
}

// This is a lengthy bit of code, since it has to recreate the operation.
// TODO(kramm): Move this under utils/ somewhere.
void EraseResults(Operation* op, llvm::BitVector erase) {
  assert(!op->getNumRegions());
  std::vector<Type> result_types;
  for (auto result : op->getResults()) {
    if (!erase[result.getResultNumber()]) {
      result_types.push_back(result.getType());
    }
  }
  OpBuilder builder(op);

  // could be folded should have a custom folder instead of relying on the
  // TensorFlow folding hook.
  if (inst == nullptr || inst->getNumResults() == 0 ||
      inst->hasTrait<OpTrait::TF::NoConstantFold>() ||
      inst->getNumRegions() != 0 || !isMemoryEffectFree(inst)) {
    return false;
  }

  // If any of the result types are variants, don't try to constant fold them.
  // This creates opaque variant constants which lose information and would