BugFix: comparasion between two signed floats was wrong
BugFix: comparasion between two signed floats was wrong

[r6129]

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