- BugFix: we really have to check both sides independently for (a ^ b) ^ a
- BugFix: we really have to check both sides independently for (a ^ b) ^ a

[r19657]

killbug2004/libfirm,MatzeB/libfirm,MatzeB/libfirm,MatzeB/libfirm,davidgiven/libfirm,MatzeB/libfirm,libfirm/libfirm,libfirm/libfirm,davidgiven/libfirm,killbug2004/libfirm,8l/libfirm,killbug2004/libfirm,davidgiven/libfirm,8l/libfirm,jonashaag/libfirm,jonashaag/libfirm,8l/libfirm,8l/libfirm,libfirm/libfirm,MatzeB/libfirm,MatzeB/libfirm,jonashaag/libfirm,killbug2004/libfirm,davidgiven/libfirm,davidgiven/libfirm,jonashaag/libfirm,killbug2004/libfirm,MatzeB/libfirm,8l/libfirm,davidgiven/libfirm,libfirm/libfirm,jonashaag/libfirm,jonashaag/libfirm,8l/libfirm,jonashaag/libfirm,killbug2004/libfirm,libfirm/libfirm,killbug2004/libfirm,8l/libfirm,davidgiven/libfirm