tree-cfgcleanup.c (cleanup_control_flow_pre): For edge removal pretend DOM info isn't available so we do not update it and...

2018-06-05  Richard Biener  <rguenther@suse.de>

	* tree-cfgcleanup.c (cleanup_control_flow_pre): For edge
	removal pretend DOM info isn't available so we do not update
	it and only remove edges, not dominated blocks.  Actually free
	DOM info in case we removed something.  Remove unreachable blocks.
	(mfb_keep_latches): Work with either DOM info or marked backedges.
	(cleanup_tree_cfg_noloop): Do not remove unreachable blocks
	first.  Mark backedges if DOM info isn't available.
	(Re-)compute DOM info after cleanup_control_flow_pre.

From-SVN: r261195