2013-08-27  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/57521
	* tree-if-conv.c (if_convertible_bb_p): Verify that at least
	one edge is non-critical.
	(find_phi_replacement_condition): Make sure to use a non-critical
	edge.  Cleanup and remove old bug workarounds.
	(bb_postdominates_preds): Remove.
	(if_convertible_loop_p_1): Do not compute post-dominators.
	(combine_blocks): Do not free post-dominators.
	(main_tree_if_conversion): Likewise.
	(pass_data_if_conversion): Add TODO_verify_ssa.

	* gcc.dg/torture/pr57521.c: New testcase.

From-SVN: r202019