2019-07-01  Richard Biener  <rguenther@suse.de>

	* tree-ssa-sccvn.c (class pass_fre): Add may_iterate
	pass parameter.
	(pass_fre::execute): Honor it.
	* passes.def: Adjust pass_fre invocations to allow iterating,
	add non-iterating pass_fre before late threading/dom.

	* gcc.dg/tree-ssa/pr77445-2.c: Adjust.

From-SVN: r272843