How to update GCC from 4.8 to 8.2 on RHEL7

Red Hat Enterprise Linux, being an "enterprise" operating system, is designed to be stable and similar for a long time. That means you do not get the "latest and greatest" by default, but a known-good implementation that remains the default on that particular RHEL version for the long term. Generally you only get substantial software upgrades by upgrading RHEL. Unfortunately, there is no RHEL 8 yet.

devtoolset allows you to switch to newer, out-of-band versions of development software like GCC, in a way that doesn't "contaminate" the whole OS installation. I used it, with great success, to get GCC 4.8 (and its C++11 support) on CentOS 6, where the official GCC is 4.4.

devtoolset-8 has GCC 8.2.1.

Or you could choose to use a distribution more suited for home users, such as Fedora.

Or you could download the GCC source and build it yourself (but ew!).

One can surely build the gcc on CentOS oneself(though ew!).

Generally follow the below steps:

sudo yum -y update
sudo yum -y install bzip2 wget gcc gcc-c++ gmp-devel mpfr-devel libmpc-devel make
gcc --version
wget http://mirrors-usa.go-parts.com/gcc/releases/gcc-8.2.0/gcc-8.2.0.tar.gz
tar zxf gcc-8.2.0.tar.gz
mkdir gcc-8.2.0-build
cd gcc-8.2.0-build
../gcc-8.2.0/configure --enable-languages=c,c++ --disable-multilib
make -j 2
sudo make install
gcc --version

At this point, many can not see 8.2, i.e.

gcc version 4.8.5 (GCC)

Just overwrite the old gcc with which just built, i.e.

# which gcc
/usr/local/bin/gcc
# cp gcc/xgcc /usr/local/bin/gcc
# gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/local/libexec/gcc/aarch64-unknown-linux-gnu/7.2.0/lto-wrapper
Target: aarch64-unknown-linux-gnu
Configured with: ../gcc-7.2.0/configure --enable-languages=c,c++ --disable-multilib
Thread model: posix
gcc version 7.2.0 (GCC)

In order to avoid library error, one may need update libstdc as well,

cp ./aarch64-unknown-linux-gnu/libstdc++-v3/src/.libs/libstdc++.so.6 /usr/local/lib64/libstdc++.so.6
cp ./stage1-aarch64-unknown-linux-gnu/libstdc++-v3/src/.libs/libstdc++.so.6 /usr/lib64/libstdc++.so.6

One may also update libc.so as well, i.e. 2.18

curl -O http://ftp.gnu.org/gnu/glibc/glibc-2.18.tar.gz
tar zxf glibc-2.18.tar.gz
cd glibc-2.18/
mkdir build
cd build/
../configure --prefix=/usr
make -j2
make install
ln -sf /usr/glibc-2.18/glibc-2.18.so /lib64/libc.so.6

Finally, type /lib64/libc.so.6 to confirm

Mostly, ln would fail, since old relations, and LD is suggested, i.e.

LD_LIBRARY_PATH=/usr/glibc-2.18/lib
export LD_LIBRARY_PATH