2016-02-24  Richard Biener  <rguenther@suse.de>

	PR middle-end/68963
	* tree-ssa-loop-niter.c (derive_constant_upper_bound_ops): Fix
	bogus check.
	(record_nonwrapping_iv): Do not fall back to the low/high bound
	for non-constant IV bases if the stmt is not always executed.

	* gcc.dg/torture/pr68963.c: New testcase.

From-SVN: r233660