reorganize g++ requirement
@@ -9,11 +9,6 @@ The following Linux distributions are recommended.
* `Ubuntu <https://www.ubuntu.com/>`_ 18.04 LTS (x86_64)
* `CentOS <https://www.centos.org/>`_ 7 (x86_64)
-.. note::
-
- CuPy requires ``g++-6`` or later.
- Follow the instructions :ref:`here <install_gcc6>` if you are using Ubuntu 16.04, CentOS 6 or 7.
-
These components must be installed to use CuPy:
* `NVIDIA CUDA GPU <https://developer.nvidia.com/cuda-gpus>`_ with the Compute Capability 3.0 or larger.
@@ -152,8 +147,11 @@ Installing CuPy from Source
Use of wheel packages are recommended whenever possible.
However, if wheels cannot meet your requirements (e.g., you are running non-Linux environment or want to use a version of CUDA / cuDNN / NCCL not supported by wheels), you can also build CuPy from source.
-When installing from source, C++ compiler such as ``g++`` is required.
-You need to install it before installing CuPy, e.g, ``apt-get install g++`` on Ubuntu 18.04.
+.. note::
+
+ CuPy source build requires ``g++-6`` or later.
+ For Ubuntu 18.04, run ``apt-get install g++``.
+ For Ubuntu 16.04, CentOS 6 or 7, follow the instructions :ref:`here <install_gcc6>`.
.. note::
