Fix amp with optiontional api bug (#40980)

* fix amp with optiontional api bug

* refine optional code for amp

paddle/fluid/eager/auto_code_generator/final_state_generator/eager_gen.py

@@ -801,10 +801,10 @@ class DygraphSingleFunctionGenerator(FunctionGeneratorBase):
                 if is_optional:
                     arg_str = f"const paddle::optional<const paddle::experimental::Tensor&> {name}"
                     amp_tensors_vector_optional_list.append(
-                        f"if ({name}.is)initialized() amp_tensors_vector.push_back({name}.get()));\n"
+                        f"if ({name}.get_ptr() != nullptr) amp_tensors_vector.push_back({{ *({name}.get_ptr()) }});\n"
                     )
                     amp_autocast_optional_list.append(
-                        f"auto NEW_{name} = {name}.is_initialized() ? egr::EagerAmpAutoCast(\"{name}\", {name}, amp_dst_dtype, op_name) : {name};\n"
+                        f"auto NEW_{name} = ({name}.get_ptr() != nullptr) ? paddle::make_optional<const paddle::experimental::Tensor&>(egr::EagerAmpAutoCast(\"{name}\", *({name}.get_ptr()), amp_dst_dtype, op_name)) : {name};\n"
                     )
                 else:
                     if inplace_map and name in inplace_map.keys():
@@ -895,7 +895,8 @@ class DygraphSingleFunctionGenerator(FunctionGeneratorBase):
             amp_tensors_vector_optional_list)
         amp_get_dst_dtype_str = f"auto amp_dst_dtype = egr::GetAmpDestDtype(op_name, amp_tensors_vector);\n"
         amp_autocast_list_str = "        ".join(
-            amp_autocast_list) + "        ".join(amp_autocast_optional_list)
+            amp_autocast_list) + "        " + "        ".join(
+                amp_autocast_optional_list)
         amp_inputs_call_args_str = ", ".join(amp_inputs_call_list)
         amp_call_str = f"return {forward_function_name}({amp_inputs_call_args_str});"
         if is_inplaced or (forward_api_name == "cast"):