Date: Fri, 05 Jan 2018 06:52:08 +0100 From: Jan Beich <jbeich@FreeBSD.org> To: toolchain@freebsd.org Cc: linimon@freebsd.org Subject: Is -march/-mtune=native actually supported on FreeBSD arm* or aarch64? Message-ID: <d12o-am47-wny@FreeBSD.org>
next in thread | raw e-mail | index | archive | help
Some ports pass -march=native and/or -mtune=native. Both are extensively
documented by GCC for x86. For other architectures some excerpts say
"native" is only supported on Linux (via /proc/cpuinfo). For example,
$ uname -p
armv6
$ echo 'int main() {}' >a.c
$ clang -march=native a.c
clang: error: the clang compiler does not support '-march=native'
$ clang -mtune=native a.c
$ pkg install -qy gcc7
$ gcc7 -march=native a.c
$ gcc7 -mtune=native a.c
$ uname -p
aarch64
$ echo 'int main() {}' >a.c
$ clang -march=native a.c
clang: error: the clang compiler does not support '-march=native'
$ clang -mtune=native a.c
clang: error: the clang compiler does not support '-mtune=native'
$ pkg install -qy gcc7
$ gcc7 -march=native a.c
$ gcc7 -mtune=native a.c
What's the rationale for Clang vs. GCC difference? Is it safe to run
FreeBSD arm* -mtune=native binaries on CPUs older than build machine?
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?d12o-am47-wny>