2016-12-14  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/78788
	* tree-vrp.c (set_value_range): Allow [-INF(OVF), +INF(OVF)].
	(set_and_canonicalize_value_range): Do not drop the above to
	VARYING.

	* gcc.dg/torture/pr78788.c: New testcase.

From-SVN: r243631