[PATCH] compiler.h: Raise minimum version of GCC to 5.1 for arm64

[Linus Torvalds]

On Thu, Jan 14, 2021 at 4:30 PM Joe Perches <joe at perches.com> wrote:
>
> KASAN v5 instead of all the old versions
> gcc 7.1 supports fallthrough.

Considering that most people won't even enable KASAN, I think that's
not a huge reason to then force people to potentially upgrade their
compilers.

That said, I do think that it might be good to just try to standardize
on the KASAN v5 code - but that could easily be done by simply making
KASAN depend as a feature on having a newer compiler version.

So the KASAN option itself could just have something like

       depends on !CC_IS_GCC || GCC_VERSION >= 70000

in it, which would allow us to just say "only v5 need apply".

As to "fallthrough", I think it's more than enough that lots of people
build with compilers that support it, and then any warnings they see
will be fixed. No need to force upgrades - it doesn't buy kernel
developers anything.

          Linus