fix quantization int8 weight save bug (#51500)

python/paddle/static/quantization/quantization_pass.py

@@ -3150,7 +3150,7 @@ class QuantWeightPass:
         self._save_int_weight = save_int_weight
         assert self._scope is not None, "scope must not be None."
         assert self._place is not None, "place must not be None."
-        self._quantized_ops = {}
+        self._quantized_ops = set()
 
     def apply(self, graph):
         assert isinstance(
@@ -3189,6 +3189,7 @@ class QuantWeightPass:
                 quant_axis = _op.op().attr("quant_axis")
                 bits_length = _op.op().attr("bit_length")
                 if x_node.name() not in self._quantized_ops:
+                    self._quantized_ops.add(x_node.name())
                     quantized_param_v = utils.quant_tensor(
                         param_v.copy(),
                         scale_v,
@@ -3211,30 +3212,10 @@ class QuantWeightPass:
                         quantized_param_v = quantized_param_v.astype(
                             save_weight_dtype
                         )
-                    quant_weight_node = graph.create_persistable_node(
-                        name=self._quantized_var_name(x_node.name()),
-                        var_type=core.VarDesc.VarType.LOD_TENSOR,
-                        shape=x_node.shape(),
-                        var_dtype=core.VarDesc.VarType.INT8,
-                    )
-                    _init_var_node(
-                        quant_weight_node,
-                        quantized_param_v,
-                        self._scope,
-                        self._place,
-                    )
-                    self._quantized_ops[x_node.name()] = quant_weight_node
+                    self._restore_var(x_node.name(), quantized_param_v)
 
                 for next_op_node in out_node.outputs:
-                    if (
-                        self._quantized_ops[x_node.name()].node
-                        in graph.graph.nodes()
-                    ):
-                        graph.update_input_link(
-                            out_node,
-                            self._quantized_ops[x_node.name()],
-                            next_op_node,
-                        )
+                    graph.update_input_link(out_node, x_node, next_op_node)
                 graph.safe_remove_nodes(_op)
         self._remove_unused_var_nodes(graph)
 
@@ -3260,11 +3241,9 @@ class QuantWeightPass:
     def _load_var(self, name):
         return np.array(self._scope.find_var(name).get_tensor())
 
-    def _quantized_var_name(self, var_name):
-        """
-        Return quantized variable name for the input `var_name`.
-        """
-        return "%s.quantized" % (var_name)
+    def _restore_var(self, name, array):
+        tensor = self._scope.find_var(name).get_tensor()
+        tensor.set(array, self._place)
 
 
 class AddQuantDequantForInferencePass: