2019-03-07  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/89595
	* tree-ssa-dom.c (dom_opt_dom_walker::optimize_stmt): Take
	stmt iterator as reference, take boolean output parameter to
	indicate whether the stmt was removed and thus the iterator
	already advanced.
	(dom_opt_dom_walker::before_dom_children): Re-iterate over
	stmts created by folding.

	* gcc.dg/torture/pr89595.c: New testcase.

From-SVN: r269453