delete_guards.patch

diff --git a/torch/_dynamo/eval_frame.py b/torch/_dynamo/eval_frame.py
index 084721a5b2f..ed9a8764849 100644
--- a/torch/_dynamo/eval_frame.py
+++ b/torch/_dynamo/eval_frame.py
@@ -320,7 +320,7 @@ class _TorchDynamoContext:
         self.export = export
         self.compiler_config = compiler_config
         self.cleanup_fns: List[Callable[[], Any]] = []
-        self.enter_exit_hooks = [backend_cache_manager(self.callback)]
+        self.enter_exit_hooks = []
         patch_fn()
 
         if dynamic is not None:
diff --git a/torch/_dynamo/guards.py b/torch/_dynamo/guards.py
index 2786be65e37..285059a7a71 100644
--- a/torch/_dynamo/guards.py
+++ b/torch/_dynamo/guards.py
@@ -594,11 +594,6 @@ class GuardBuilder(GuardBuilderBase):
     def BACKEND_MATCH(self, guard: Guard):
         """Guard on backend matching based on id of current_backend"""
         assert guard.source is GuardSource.GLOBAL
-        backend_id = (
-            f"{id(torch._dynamo.eval_frame.guarded_backend_cache.current_backend)}"
-        )
-        code = [f"___check_current_backend({backend_id})"]
-        self._produce_guard_code(guard, code)
 
     def SHAPE_ENV(self, guard: Guard):
         # Let's handle ShapeEnv guards.  To do this, we will resolve
diff --git a/torch/csrc/dynamo/eval_frame.c b/torch/csrc/dynamo/eval_frame.c
index 5982022ce10..de00f18eae0 100644
--- a/torch/csrc/dynamo/eval_frame.c
+++ b/torch/csrc/dynamo/eval_frame.c
@@ -651,25 +651,7 @@ static PyObject* lookup(CacheEntry* e, THP_EVAL_API_FRAME_OBJECT *frame, CacheEn
     // NB: intentionally not using Py_RETURN_NONE, to return borrowed ref
     return Py_None;
   }
-  PyObject *f_locals = frame->f_locals;
-  // remember to update the type signature for GuardFn.__call__ in torch/_dynamo/types.py
-  // if this calling convention changes
-  PyObject* valid = PyObject_CallOneArg(e->check_fn, f_locals);
-  if (unlikely(valid == NULL)) {
-    if (guard_error_hook != NULL) {
-      PyObject *type = NULL, *value = NULL, *traceback = NULL;
-      PyErr_Fetch(&type, &value, &traceback);
-      PyObject* r = call_guard_fail_hook(guard_error_hook, e, index, f_locals);
-      if (r == NULL) {
-        return NULL;
-      }
-      Py_DECREF(r);
-      PyErr_Restore(type, value, traceback);
-    }
-    return NULL;
-  }
-  Py_DECREF(valid);
-  if (valid == Py_True) {
+  if (true) {
     // Keep the head as the most recently used cache entry.
     // If the hit cache entry is not the head of the linked list,
     // move it to the head
@@ -945,14 +927,6 @@ static PyObject* _custom_eval_frame(
   CacheEntry* cache_entry = extract_cache_entry(extra);
   FrameState* frame_state = extract_frame_state(extra);
 
-  // TODO(jansel): investigate directly using the "fast" representation
-  // TODO(alband): This is WRONG for python3.11+ we pass in a _PyInterpreterFrame
-  // even though we should pass a PyFrameObject.
-  if (THP_PyFrame_FastToLocalsWithError(frame) < 0) {
-    DEBUG_TRACE("error %s", get_frame_name(frame));
-    return NULL;
-  }
-
   // A callback of Py_False indicates "run only" mode, the cache is checked, but
   // we never compile.
   if (callback == Py_False) {
@@ -973,7 +947,6 @@ static PyObject* _custom_eval_frame(
     DEBUG_TRACE("cache hit %s", get_frame_name(frame));
     return eval_custom_code(tstate, frame, cached_code, throw_flag);
   }
-  DEBUG_CHECK(PyDict_CheckExact(frame->f_locals));
   DEBUG_CHECK(PyDict_CheckExact(frame->f_globals));
   DEBUG_CHECK(PyDict_CheckExact(frame->f_builtins));
 
@@ -996,6 +969,13 @@ static PyObject* _custom_eval_frame(
     eval_frame_callback_set(callback);
     return eval_custom_code(tstate, frame, cached_code, throw_flag);
   }
+
+  // only populate frame->f_locals on a cache miss
+  if (THP_PyFrame_FastToLocalsWithError(frame) < 0) {
+    DEBUG_TRACE("error %s", get_frame_name(frame));
+    return NULL;
+  }
+
   // cache miss
   // TODO(alband): This is WRONG for python3.11+ we pass in a _PyInterpreterFrame
   // that gets re-interpreted as a PyObject (which it is NOT!)