message: VLOG which args are hoisted as constants.
diff: @@ -607,6 +607,9 @@ XlaComputationLaunchContext::BuildXlaCompilerArguments(
  absl::Span<const Tensor* const> inputs,
  absl::Span<VariableInfo const> variable_args, Device* device) {
  CHECK(absl::c_is_sorted(must_be_constant_idxs));
  + VLOG(2) << "Must be const args: {"
  + << absl::StrJoin(must_be_constant_idxs, ",") << "} out of "
  + << inputs.size() << " args";
  std::vector<XlaCompiler::Argument> out;
  out.resize(inputs.size());
  