[dynamo][cpp-guards] Disable dict-tag optim if the guard_manager has child accessors (pytorch#147694)

Pull Request resolved: pytorch#147694
Approved by: https://github.com/isuruf

Author: anijain2305

torch/csrc/dynamo/guards.cpp

@@ -2535,6 +2535,10 @@ class GuardManager {
     return GuardDebugInfo(true, num_guards_executed);
   }
 
+  bool has_no_accessors() {
+    return _accessors.empty();
+  }
+
   int64_t fail_count() const {
     return _fail_count;
   }
@@ -3780,8 +3784,12 @@ class DictGetItemGuardAccessor : public GuardAccessor {
   // NB: Intentional duplication between check_nopybind and
   // check_verbose_nopybind.
   bool check_nopybind(PyObject* obj, bool matches_dict_tag = false) override {
-    if (matches_dict_tag && _is_immutable_object) {
+    if (matches_dict_tag && _is_immutable_object &&
+        _guard_manager->has_no_accessors()) {
       // immutable object and dict tag matches, we can skip the guard subtree.
+      // NB: We only skip the subtree if there are no accessors in the subtree.
+      // This is specificallly for tensors which are used in symbolic shape C++
+      // guards, and therefore have accessors on the tensor GuardManager itself.
       return true;
     }