gcc/:
	* common.opt (fkeep-gc-roots-live): New undocumented option.
	* tree-ssa-loop-ivopts.c (add_candidate_1): If
	-fkeep-gc-roots-live, skip pointers.
	(add_iv_candidate_for_biv): Handle add_candidate_1 returning
	NULL.

gcc/testsuite/:
	* gcc.dg/tree-ssa/ivopt_5.c: New test.

From-SVN: r232888