GCC optimization script

#!/bin/sh



# Author: pixelbeat



#This script is Linux specific

#It should work on any gcc >= 2.95 at least



#these apply to any arch (just here for reference)

unsafe_math_opts="-ffast-math -fno-math-errno -funsafe-math-optimizations -fno-trapping-math"



gcc_version=`gcc -dumpversion | sed 's/\([0-9]\{1,\}\.[0-9]\{1,\}\)\.*\([0-9]\{1,\}\)\{0,1\}/\1\2/'`



IFS=":"

while read name value; do

    unset IFS

    name=`echo $name`

    value=`echo $value`

    IFS=":"

    if [ "$name" == "vendor_id" ]; then

        vendor_id="$value"

    elif [ "$name" == "cpu family" ]; then

        cpu_family="$value"

    elif [ "$name" == "model" ]; then

        cpu_model="$value"

    elif [ "$name" == "flags" ]; then

        flags="$value"

    fi

done < /proc/cpuinfo

unset IFS



if [ "$vendor_id" == "AuthenticAMD" ]; then

    if [ "$cpu_family" == "4" ]; then

        _CFLAGS="$_CFLAGS -march=i486"

    elif [ "$cpu_family" == "5" ]; then

        if [ "$cpu_model" -lt "4" ]; then

            _CFLAGS="$_CFLAGS -march=pentium"

        elif [ "$cpu_model" == "6" ] || [ "$cpu_model" == "7" ]; then

            _CFLAGS="$_CFLAGS -march=k6"

        elif [ "$cpu_model" == "8" ] || [ "$cpu_model" == "12" ]; then

            if expr $gcc_version '>=' 3.1 >/dev/null; then

                _CFLAGS="$_CFLAGS -march=k6-2"

            else

                _CFLAGS="$_CFLAGS -march=k6"

            fi

        elif [ "$cpu_model" == "9" ] || [ "$cpu_model" == "13" ]; then

            if expr $gcc_version '>=' 3.1 >/dev/null; then

                _CFLAGS="$_CFLAGS -march=k6-3"

            else

                _CFLAGS="$_CFLAGS -march=k6"

            fi

        fi

    elif [ "$cpu_family" == "6" ]; then

        if [ "$cpu_model" -le "3" ]; then

            if expr $gcc_version '>=' 3.0 >/dev/null; then

                _CFLAGS="$_CFLAGS -march=athlon"

            else

                _CFLAGS="$_CFLAGS -march=k6"

            fi

        elif [ "$cpu_model" == "4" ]; then

            if expr $gcc_version '>=' 3.1 >/dev/null; then

                _CFLAGS="$_CFLAGS -march=athlon-tbird"

            elif expr $gcc_version '>=' 3.0 >/dev/null; then

                _CFLAGS="$_CFLAGS -march=athlon"

            else

                _CFLAGS="$_CFLAGS -march=k6"

            fi

        elif [ "$cpu_model" -ge "6" ]; then #athlon-{4,xp,mp}

            if expr $gcc_version '>=' 3.1 >/dev/null; then

                _CFLAGS="$_CFLAGS -march=athlon-xp"

            elif expr $gcc_version '>=' 3.0 >/dev/null; then

                _CFLAGS="$_CFLAGS -march=athlon"

            else

                _CFLAGS="$_CFLAGS -march=k6"

            fi

        fi

    fi

else #everything else "GenuineIntel"

    if [ "$cpu_family" == "3" ]; then

        _CFLAGS="$_CFLAGS -march=i386"

    elif [ "$cpu_family" == "4" ]; then

        _CFLAGS="$_CFLAGS -march=i486"

    elif [ "$cpu_family" == "5" ] && expr $gcc_version '<' 3.1 >/dev/null; then

        _CFLAGS="$_CFLAGS -march=pentium"

    elif [ "$cpu_family" -ge "6" ] && expr $gcc_version '<' 3.1 >/dev/null; then

        _CFLAGS="$_CFLAGS -march=pentiumpro"

    elif [ "$cpu_family" == "5" ]; then

        if [ "$cpu_model" != "4" ]; then

            _CFLAGS="$_CFLAGS -march=pentium"

        else

            _CFLAGS="$_CFLAGS -march=pentium-mmx" #No overlap with other vendors

        fi

    elif [ "$cpu_family" == "6" ]; then

        if echo "$flags" | grep -vq cmov; then #gcc incorrectly assumes i686 always has cmov

            _CFLAGS="$_CFLAGS -march=pentium -mcpu=pentiumpro" #VIA CPUs exhibit this

        else

            if [ "$cpu_model" == "0" ] || [ "$cpu_model" == "1" ]; then

                _CFLAGS="$_CFLAGS -march=pentiumpro"

            elif [ "$cpu_model" -ge "3" ] && [ "$cpu_model" -le "6" ]; then #4=TM5600 at least

                _CFLAGS="$_CFLAGS -march=pentium2"

            elif [ "$cpu_model" -ge "7" ] && [ "$cpu_model" -le "11" ]; then #9 invalid

                _CFLAGS="$_CFLAGS -march=pentium3"

            fi

        fi

    elif [ "$cpu_family" == "15" ]; then

        _CFLAGS="$_CFLAGS -march=pentium4"

    fi

fi



if expr $gcc_version '>=' 3.1 >/dev/null; then

    if echo "$flags" | grep -q sse2; then

        _CFLAGS="$_CFLAGS -mfpmath=sse -msse2"

    elif echo "$flags" | grep -q sse; then

        _CFLAGS="$_CFLAGS -mfpmath=sse -msse"

    fi

    if echo "$flags" | grep -q mmx; then

        _CFLAGS="$_CFLAGS -mmmx"

    fi

    if echo "$flags" | grep -q 3dnow; then

        _CFLAGS="$_CFLAGS -m3dnow"

    fi

fi



echo "$_CFLAGS"