if ! echo "${CFLAGS} ${CXXFLAGS} ${LDFLAGS}" | \
   grep -E '\-f(no\-)?profile' >/dev/null; then

    FEATURES="-usersandbox"  # does not work here, use nosandbox.conf

    PROFILE_ROOT="/etc/portage/env/profiles/${PN}/${PVR}"
    PROFILE_SUFFIX="_e1/_e2/_e3" # somepackage writes to ../../
    PROFILE_DIR="${PROFILE_ROOT}/${PROFILE_SUFFIX}"

    PROFILE_USE="-fprofile-dir=\"${PROFILE_DIR}\" -fprofile-use -fprofile-correction"
    PROFILE_GEN="-fprofile-dir=\"${PROFILE_DIR}\" -fprofile-generate -fno-lto"
    # ^ saves bugs and memory (4.9.1)
    # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=45375#c31

    if [ ! -d "${PROFILE_DIR}" ]; then
        mkdir -p "${PROFILE_DIR}"
    fi

    if [ -e "${PROFILE_ROOT}/.is_generated" -a \
        ! -e "${PROFILE_ROOT}/.is_compiled" ]; then
        chown -R root:root "${PROFILE_ROOT}"
        chmod -R a-w+r "${PROFILE_ROOT}"

        export _COMPILING_PROFILE_ROOT="${PROFILE_ROOT}"    # catched in .bashrc
        CFLAGS="${CFLAGS} ${PROFILE_USE}"
        CXXFLAGS="${CXXFLAGS} ${PROFILE_USE}"
        LDFLAGS="${LDFLAGS} ${PROFILE_USE}"
    else
        chown -R portage:users "${PROFILE_ROOT}"
        chmod -R og+rw "${PROFILE_ROOT}"

        export _GENERATING_PROFILE_ROOT="${PROFILE_ROOT}"    # catched in .bashrc
        CFLAGS="${CFLAGS} ${PROFILE_GEN}"
        CXXFLAGS="${CXXFLAGS} ${PROFILE_GEN}"
        LDFLAGS="${LDFLAGS} ${PROFILE_GEN}"
    fi
fi