[Bug c/70210] New: -march=native and -mcpu=native do not detect ARM cortex-a53 in 32 bit mode on Linux

["andrewm.roberts at sky dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70210

            Bug ID: 70210
           Summary: -march=native and -mcpu=native do not detect ARM
                    cortex-a53 in 32 bit mode on Linux
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: andrewm.roberts at sky dot com
  Target Milestone: ---

When using -march=native or -mcpu=native with gcc-6-20160306 snapshot (and also
on previous released versions), the ARM cortex-a53 CPU is not detected in 32
bit mode. This CPU is used on the Raspberry Pi 3 (BCM2834) amongst others.

Tested on Arch Linux ARM:

uname -a
Linux alarmpi 4.1.19-2-ARCH #1 SMP Sat Mar 5 22:22:01 MST 2016 armv7l GNU/Linux

cat /proc/cpuinfo
processor       : 0
model name      : ARMv7 Processor rev 4 (v7l)
BogoMIPS        : 76.80
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

processor       : 1
model name      : ARMv7 Processor rev 4 (v7l)
BogoMIPS        : 76.80
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

processor       : 2
model name      : ARMv7 Processor rev 4 (v7l)
BogoMIPS        : 76.80
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

processor       : 3
model name      : ARMv7 Processor rev 4 (v7l)
BogoMIPS        : 76.80
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

Hardware        : BCM2709
Revision        : a02082
Serial          : 00000000xxxxxxxx

/usr/local/gcc-6.0.0/bin/gcc -v
Using built-in specs.
COLLECT_GCC=/usr/local/gcc-6.0.0/bin/gcc
COLLECT_LTO_WRAPPER=/usr/local/gcc-6.0.0/libexec/gcc/armv7l-unknown-linux-gnueab
ihf/6.0.0/lto-wrapper
Target: armv7l-unknown-linux-gnueabihf
Configured with: ../gcc-6.0.0/configure --prefix=/usr/local/gcc-6.0.0
--program-
suffix= --enable-languages=c,c++,fortran --enable-shared --enable-threads=posix 
--with-system-zlib --with-isl --enable-__cxa_atexit
--disable-libunwind-exceptio
ns --enable-clocale=gnu --disable-libstdcxx-pch --disable-libssp
--enable-gnu-un
ique-object --enable-linker-build-id --enable-lto --enable-plugin
--enable-insta
ll-libiberty --with-linker-hash-style=gnu --enable-gnu-indirect-function
--disab
le-multilib --disable-werror --enable-checking=release
--host=armv7l-unknown-lin
ux-gnueabihf --build=armv7l-unknown-linux-gnueabihf
--target=armv7l-unknown-linu
x-gnueabihf --with-arch=armv7-a --with-float=hard --with-fpu=vfpv3-d16
--disable
-bootstrap
Thread model: posix
gcc version 6.0.0 20160306 (experimental) (GCC) 

The CPU part table in gcc/config/arm/driver-arm.c does not include the
cortex-a53 part number (0xd03).