fix pipeline float status uninitialized

Author: wangxicoding

python/paddle/fluid/optimizer.py

@@ -4654,18 +4654,22 @@ def _add_op_device_attr_for_op(self, op, idx, block):
                     op.type == 'elementwise_div'):
                 device = f"{self._device}:all"
             op._set_attr(self._op_device_key, device)
-        elif self._is_weight_decay_op(op) and op.type == 'scale':
-            # set AdamW decay_coeff to device:all
-            op._set_attr(self._op_device_key, f"{self._device}:all")
         elif op.type == "alloc_float_status" or op.type == "clear_float_status":
             op._set_attr(self._op_device_key, f"{self._device}:all")
             # NOTE(wangxi): NPU should only clear the float status
             # once at each batch step
             op._set_attr(self._op_role_key, self._op_role.LRSched)
+
+            float_status_name = op.output_arg_names[0]
+            float_status_var = block.var(float_status_name)
+            # FIXME(wangxi): pipeline lr schedule will exec on sub_scope(0)
+            # while update will exec on sub_scope(last_micro_step), should
+            # set persistable to use global scope
+            float_status_var.persistable = True
         else:
             other_known_ops = [
                 'update_loss_scaling', 'reduce_any', 'concat', 'sum',
-                'check_finite_and_unscale', 'alloc_float_status', 'memcpy'
+                'check_finite_and_unscale', 'memcpy'
             ]
             assert op.type in other_known_ops, "For other ops without " \
                 "op_device set, they must be one of {}, but it " \