Reduce SCCs in IPA postorder.

Reduce SCCs in IPA postorder.

2019-06-10  Martin Liska  <mliska@suse.cz>

	* ipa-cp.c (ignore_edge_p): New function.
	(build_toporder_info): Use it.
	* ipa-inline.c (ignore_edge_p): New function/
	(inline_small_functions): Use it.
	* ipa-pure-const.c (ignore_edge_for_nothrow):
	Verify opt_for_fn for caller and callee.
	(ignore_edge_for_pure_const): Likewise.
	* ipa-reference.c (ignore_edge_p): Extend to check
	for opt_for_fn.
	* ipa-utils.c (searchc): Refactor.
	* ipa-utils.h: Fix coding style.

From-SVN: r272115