message: fix two issues in the previous commit
diff: @@ -193,8 +193,8 @@ ENOKI_INLINE Result vcall_autodiff(const char *name, const Func &func,
  auto [base, n_inst] = vcall_registry_get(backend_v<Self>, Base::Domain);
  // CustomOp only needed if > 1 instance and AD is enabled
  - if (unlikely((n_inst > 1 || !jit_flag(JitFlag::VCallInline) &&
  - detail::ad_enabled<Type>())))
  + if (ENOKI_UNLIKELY((n_inst > 1 || !jit_flag(JitFlag::VCallInline)) &&
  + detail::ad_enabled<Type>()))
  return custom<DiffVCall<DiffType, Self, Result, Func, Args...>>(
  name, self, func, args...);
  }
  