cherry-pick 30354 (#30407)

python/paddle/fluid/contrib/slim/quantization/imperative/qat.py

@@ -255,13 +255,19 @@ class ImperativeQuantAware(object):
             if hasattr(layer, "skip_quant") and layer.skip_quant == True:
                 continue
 
-            scopes = name.split('.')
-            target = scopes[-1]
+            last_idx = 0
+            idx = 0
             obj = model
             parent = model
-            for i in range(len(scopes) - 1):
-                obj = getattr(parent, scopes[i])
+
+            while idx < len(name):
+                if (name[idx] == '.'):
+                    if hasattr(parent, name[last_idx:idx]):
+                        obj = getattr(obj, name[last_idx:idx])
                         parent = obj
+                        last_idx = idx + 1
+                idx += 1
+            target = name[last_idx:idx]
 
             quant_layer = self._get_quantized_counterpart(layer)
             setattr(quant_layer, "layer_name", layer.full_name())