Hi Everyone,
I'm having trouble with ARMv8/Aarch64. One is an early Mustang server board (without CRC or Crypto), and the other is a LeMaker HiKey (with CRC and Crypto). Both run Linaro:
apm-mustang: $ cat /proc/cpuinfo Features : fp asimd evtstrm
And:
hikey: $ cat /proc/cpuinfo Features : fp asimd evtstrm aes pmull sha1 sha2 crc32
According to the GCC folks, we can get better code generation with -mfpu=neon-fp-armv8 (http://gcc.gnu.org/ml/gcc-help/2016-05/msg00058.html and https://gcc.gnu.org/onlinedocs/gcc/ARM-Options.html). However, it results in:
$ g++ -DDEBUG -g3 -O0 -mfpu=neon-fp-armv8 -fPIC -pipe -c cryptlib.cpp g++: error: unrecognized command line option ‘-mfpu=neon-fp-armv8’ GNUmakefile:753: recipe for target 'cryptlib.o' failed
It looks like -mfpu=neon-fp-armv8 is a GCC 4.9 feature (http://gcc.gnu.org/gcc-4.9/changes.html), and Linaro supplies GCC 4.9.2:
$ g++ --version g++ (Debian/Linaro 4.9.2-10) 4.9.2 Copyright (C) 2014 Free Software Foundation, Inc.
I'm wonder why the option is not being consumed by GCC. Are there any ideas what I should be doing differently?
Thanks in advance.
Jeff