Hi Andrew, Thanks for the information. So does it mean gcc will not recognize the 'mfpu' option itself for aarch64 ?
Linaro ToolChain FAQ says along with '-mfpu', we also need to specify -mfloat-abi=softfp|hard otherwise VFP/Neon/Crypto instructions will not be generated. Also Linaro connect presentation ( http://www.slideshare.net/linaroorg/lcu14-307-advanced-toolchain-usage-parts-12) suggest to pass '-funsafe-math-optimizations' since NEON does not support full IEEE 754. Are such flags restrictions are still applicable ? Please also tell how can we disable NEON/SIMD instructions in gcc for aarch64. Thanks. On 10 June 2015 at 11:05, Pinski, Andrew <andrew.pin...@caviumnetworks.com> wrote: > -march=native was not included in GCC 5.1 that Linaro provided. I don't > know if Linaro has plans to backport the support it but it is already there > for GCC 6. > > You don't need -mfpu=neon for AARCH64 at all. AARCH64 defaults to having > simd turned on. > > > Thanks, > > Andrew Pinski > ------------------------------ > *From:* linaro-toolchain <linaro-toolchain-boun...@lists.linaro.org> on > behalf of Virendra Kumar Pathak <kumarvir.pat...@gmail.com> > *Sent:* Tuesday, June 9, 2015 10:26 PM > *To:* Linaro Toolchain Mailman List > *Subject:* mfpu=neon and -march=native on aarch64-linux-gnu toolchain > > Hi Linaro Toolchain Group, > > I have questions regarding -mfpu=neon and -march=native w.r.t aarch64 > linaro native toolchain (aarch64-linux-gnu) > I found gcc is not accepting these flags. > > On juno Board: > > gcc -mfpu=neon hello.c -o hello > gcc: error: unrecognized command line option '-mfpu=neon' > > gcc -march=native hello.c -o hello > hello.c:1:0: error: unknown value 'native' for –march > > Am I missing something ? Please help. > > > Below is the machine details > > uname -a > Linux juno 3.10.55.0-1-linaro-lt-vexpress64 #1ubuntu1~ci+141022094025 SMP > Wed Oct 22 09:41:06 UTC 2014 aarch64 aarch64 aarch64 GNU/Linux > > gcc -v > Using built-in specs. > COLLECT_GCC=gcc > > COLLECT_LTO_WRAPPER=/usr/local/apps/gcc-native/gcc-linaro-5.1-2015.06.06.native-i686-mingw32_aarch64-linux-gnu/bin/../libexec/gcc/aarch64-linux-gnu/5.1.1/lto-wrapper > Target: aarch64-linux-gnu > Configured with: > '/home/user_name/vpathak/build_abe/snapshots/gcc.git~linaro-4.9-branch/configure' > SHELL=/bin/sh --with-bugurl=https://bugs.linaro.org > --with-mpc=/home/user_name/vpathak/build_abe/builds/destdir/aarch64-linux-gnu > --with-mpfr=/home/user_name/vpathak/build_abe/builds/destdir/aarch64-linux-gnu > --with-gmp=/home/user_name/vpathak/build_abe/builds/destdir/aarch64-linux-gnu > --with-gnu-as --with-gnu-ld --disable-libstdcxx-pch --disable-libmudflap > --with-cloog=no --with-ppl=no --with-isl=no --disable-nls > --enable-multiarch --disable-multilib --enable-c99 --with-arch=armv8-a > --disable-shared --enable-static > --with-build-sysroot=/home/user_name/vpathak/build_abe/sysroots/aarch64-linux-gnu > --enable-lto --enable-linker-build-id --enable-long-long --enable-shared > --with-sysroot=/home/user_name/vpathak/build_abe/builds/destdir/aarch64-linux-gnu/aarch64-linux-gnu/libc > --enable-languages=c,c++,fortran,lto --enable-fix-cortex-a53-835769 > --enable-checking=release --disable-bootstrap --with-bugurl= > https://bugs.linaro.org --build=x86_64-unknown-linux-gnu > --host=aarch64-linux-gnu --target=aarch64-linux-gnu > --prefix=/home/user_name/vpathak/build_abe/builds/destdir/aarch64-linux-gnu > Thread model: posix > gcc version 5.1.1 (GCC) > > Thanks. > -- > with regards, > Virendra Kumar Pathak > -- with regards, Virendra Kumar Pathak
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