497 static GLboolean is_undef( struct ureg reg )  in is_undef()  function
505    if (is_undef(p->identity))  in get_identity_param()
721    if (is_undef(p->eye_position)) {  in get_eye_position()
747    if (!is_undef(p->eye_position))  in get_eye_position_z()
750    if (is_undef(p->eye_position_z)) {  in get_eye_position_z()
768    if (is_undef(p->eye_position_normalized)) {  in get_eye_position_normalized()
780    if (is_undef(p->transformed_normal) &&  in get_transformed_normal()
787    else if (is_undef(p->transformed_normal))  in get_transformed_normal()
981    if (p->state->unit[i].light_attenuated && !is_undef(dist)) {  in calculate_light_attenuation()
982       if (is_undef(att))  in calculate_light_attenuation()
985       if (is_undef(attenuation))  in calculate_light_attenuation()
1278 	    if (!is_undef(att)) {  in build_lighting()
1352 	    if (!is_undef(att)) {  in build_lighting()
1578 	    struct ureg in = (!is_undef(out_texgen) ?  in build_texture_transform()