tree-if-conv.c (add_to_predicate_list): Check unconditionally that bb is always executed to early exit.

gcc/

	* tree-if-conv.c (add_to_predicate_list): Check unconditionally
	that bb is always executed to early exit. Use predicate of
	cd-equivalent block for join blocks if it exists.
	(if_convertible_loop_p_1): Recompute POST_DOMINATOR tree.
	(tree_if_conversion): Free post-dominance information.

gcc/testsuite/

	* gcc.dg/tree-ssa/ifc-cd.c: New test.

From-SVN: r217277