fix attrs copy error (#51056)

python/paddle/incubate/autograd/primx.py

@@ -655,16 +655,10 @@ def _lower_composite(block, blacklist=[]):
                 for i in range(len(op.output_names)):
                     outputs[op.output_names[i]] = op.output(op.output_names[i])
 
-                attrs = {}
-                # When copying op, all attrs defined in api should be kept.But op.attr_names is not complete here.
-                # Thus, all attrs should be got from init attrs of origin op.
-                runtime_attrs = op._get_runtime_attrs()
-                for name in runtime_attrs.keys():
-                    attrs[name] = runtime_attrs[name]
-
                 from paddle.fluid.dygraph.base import param_guard
 
                 new_op_desc = block.desc.append_op()
+                new_op_desc.copy_from(op.desc)
                 with param_guard(inputs), param_guard(outputs):
                     op = Operator(
                         block=block,
@@ -672,7 +666,7 @@ def _lower_composite(block, blacklist=[]):
                         type=op.type,
                         inputs=inputs,
                         outputs=outputs,
-                        attrs=attrs,
+                        attrs=None,
                     )
                 block.ops.append(op)