Clean-up EH after strlen transformation (PR tree-optimization/83593).

Clean-up EH after strlen transformation (PR tree-optimization/83593).

2018-01-03  Martin Liska  <mliska@suse.cz>

	PR tree-optimization/83593
	* tree-ssa-strlen.c: Include tree-cfg.h.
	(strlen_check_and_optimize_stmt): Add new argument cleanup_eh.
	(strlen_dom_walker): Add new member variable m_cleanup_cfg.
	(strlen_dom_walker::strlen_dom_walker): Initialize m_cleanup_cfg
	to false.
	(strlen_dom_walker::before_dom_children): Call
	gimple_purge_dead_eh_edges. Dump tranformation with details
	dump flags.
	(strlen_dom_walker::before_dom_children): Update call by adding
	new argument cleanup_eh.
	(pass_strlen::execute): Return TODO_cleanup_cfg if needed.
2018-01-03  Martin Liska  <mliska@suse.cz>

	PR tree-optimization/83593
	* gcc.dg/pr83593.c: New test.

From-SVN: r256178