PR tree-optimization/79159
	* tree-ssa-loop-niter.c (get_cst_init_from_scev): New function.
	(record_nonwrapping_iv): Imporve boundary using above function if no
	value range information.

	gcc/testsuite
	PR tree-optimization/79159
	* g++.dg/tree-ssa/pr79159.C: New test.

From-SVN: r244868