- [ ] I have searched the [issues](https://github.com/vueComponent/ant-design-vue/issues) of this repository and believe that this is not a duplicate. ### Version 1.7.7 ### Environment "ant-design-vue": "1.7.8", "moment": "2.22.1", "vue": "2.5.17" ### Reproduction link [](https://codesandbox.io/s/vue-antd-template-forked-4suyp) ### Steps to reproduce 设置精度为0, 输入-1.5, 查看结果 ### What is expected? -2 ### What is actually happening? -1 <!-- generated by issue-helper. DO NOT REMOVE -->