$ echo "int main() { return 0; }" |LANG=en gcc `echo  -march=native` -v -E -x c - 2>&1 | grep arch
Configured with: ../src/configure -v --with-pkgversion='Ubuntu/Linaro 4.5.2-8ubuntu4' --with-bugurl=file:///usr/share/doc/gcc-4.5/README.Bugs --enable-languages=c,c++,fortran,objc,obj-c++ --prefix=/usr --program-suffix=-4.5 --enable-shared --enable-multiarch --with-multiarch-defaults=i386-linux-gnu --enable-linker-build-id --with-system-zlib --libexecdir=/usr/lib/i386-linux-gnu --without-included-gettext --enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.5 --libdir=/usr/lib/i386-linux-gnu --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-plugin --enable-gold --enable-ld=default --with-plugin-ld=ld.gold --enable-objc-gc --enable-targets=all --disable-werror --with-arch-32=i686 --with-tune=generic --enable-checking=release --build=i686-linux-gnu --host=i686-linux-gnu --target=i686-linux-gnu
 /usr/lib/i386-linux-gnu/gcc/i686-linux-gnu/4.5.2/cc1 -E -quiet -v - -D_FORTIFY_SOURCE=2 -march=nocona -mcx16 --param l1-cache-size=16 --param l1-cache-line-size=64 --param l2-cache-size=2048 -mtune=nocona -fstack-protector
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