gcc-opt software package provides allow global optimization flags for gcc, g++, you can install in your Ubuntu 16.04 LTS (Xenial Xerus) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install gcc-opt
gcc-opt is installed in your system.
Make ensure the gcc-opt package were installed using the commands given below,
$ sudo dpkg-query -l | grep gcc-opt *
You will get with gcc-opt package name, version, architecture and description in a table
| Distro | Ubuntu 16 04 lts xenial xerus |
| Section | Development |
| Package | gcc-opt |
| Version | 1.2 |
| Description | allow global optimization flags for gcc, g++ |
| Sub Section | Devel |