But when you are an enterprise too afraid to upgrade your version of RHEL then GCC 5.4 <= may be what you have.
I know a company that paid a considerable amount of money to am outside team to get the current release of GCC running on their no longer supported version of RHEL.
GCC 5.4 is more than two years old; the current version is 8.2¹.
1. https://www.gnu.org/software/gcc/releases.html