Add an additional PhiM check: Predecessors of Phi M must be pairwise identical or from different blocks.
Add an additional PhiM check:
Predecessors of Phi M must be pairwise identical or from different blocks.

[r7960]

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