[Bug target/82175] -march=native fails on armv7 big/little system armv7l-unknown-linux-gnueabihf with gcc 8.0.0

[andrewm.roberts at sky dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82175

--- Comment #1 from Andrew Roberts <andrewm.roberts at sky dot com> ---
This also fails on a Raspberry PI 3 running armv7 in the same way.
Looks like the armv8 code has got mixed up with the armv7 code...

The RPI3 has:
4x ARM Cortex-A53 rev 4 (0x4100d030)

cat /proc/cpuinfo
processor       : 0
model name      : ARMv7 Processor rev 4 (v7l)
BogoMIPS        : 38.40
Features        : half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva idivt
vfpd32 lpae evtstrm crc32
CPU implementer : 0x41
CPU architecture: 7
CPU variant     : 0x0
CPU part        : 0xd03
CPU revision    : 4
...

It does work ok on a different armv8 (aarch64) system:
Odroid-C2, this uses the same processors as the RPI3, but is running an aarch64
linux OS.
4 x ARM Cortex-A53 rev 4 (0x4100d030)

cat /proc/cpuinfo
processor       : 0
BogoMIPS        : 2.00
Features        : fp asimd crc32
CPU implementer : 0x41
CPU architecture: 8
CPU variant     : 0x0
CPU part        : 0xd03
CPU revision    : 4
...

On the ODROID-C2 in aarch64 mode:
/usr/local/gcc/bin/gcc -Q --help=target | grep march
  -march=ARCH                           armv8-a