Bail out early if the inner block has side effects or is otherwise not
eligible for ifcombine.

for  gcc/ChangeLog

	* tree-ssa-ifcombine.c (tree_ssa_ifcombine_bb_1): Factor out
	bb_no_side_effects_p tests...
	(tree_ssa_ifcombine_bb): ... here.

From-SVN: r229691