PR tree-optimization/81388
	Revert r238585:
	2016-07-21  Bin Cheng  <bin.cheng@arm.com>

	* tree-ssa-loop-niter.c (number_of_iterations_lt_to_ne): Clean up
	by removing computation of may_be_zero.

	gcc/testsuite
	PR tree-optimization/81388
	* gcc.dg/tree-ssa/pr81388-1.c: New test.
	* gcc.dg/tree-ssa/pr81388-2.c: New test.

From-SVN: r250384