The pass would free the dominance info after making a change, but it
should be pretty easy to keep the information up-to-date when the call
has no EH edges.

Tested on x86_64-linux-gnu, arm-linux-gnueabi and aarch64-linux-gnu.

gcc/
	* tree-call-cdce.c (shrink_wrap_one_built_in_call): Try to update
	the dominance info; free it if we can't.
	(pass_call_cdce::execute): Don't free the dominance info here.

From-SVN: r229916