Add extra checks for places assuming one argument loop close SSA form.

2010-04-01  Sebastian Pop  <sebastian.pop@amd.com>

	* graphite-sese-to-poly.c (rewrite_close_phi_out_of_ssa): Assert that
	gimple_phi_num_args of the loop close SSA phi node is equal to 1.
	(detect_commutative_reduction): Same.

From-SVN: r158025