2014-04-28  Richard Biener  <rguenther@suse.de>

	* tree-vrp.c (vrp_var_may_overflow): Remove.
	(vrp_visit_phi_node): Rather than bumping to +-INF possibly
	with overflow immediately bump to one before that value and
	let iteration figure out overflow status.

	* gcc.dg/tree-ssa/vrp91.c: New testcase.
	* gcc.dg/Wstrict-overflow-14.c: XFAIL.
	* gcc.dg/Wstrict-overflow-15.c: Likewise.
	* gcc.dg/Wstrict-overflow-18.c: Remove XFAIL.

From-SVN: r209862