re PR tree-optimization/48052 (loop not vectorized if index is "unsigned int")

re PR tree-optimization/48052 (loop not vectorized if index is "unsigned int")

	PR tree-optimization/48052
	* cfgloop.h (struct control_iv): New.
	(struct loop): New field control_ivs.
	* tree-ssa-loop-niter.c : Include "stor-layout.h".
	(number_of_iterations_lt): Set no_overflow information.
	(number_of_iterations_exit): Init control iv in niter struct.
	(record_control_iv): New.
	(estimate_numbers_of_iterations_loop): Call record_control_iv.
	(loop_exits_before_overflow): New.  Interface factored out of
	scev_probably_wraps_p.
	(scev_probably_wraps_p): Factor loop niter related code into
	loop_exits_before_overflow.
	(free_numbers_of_iterations_estimates_loop): Free control ivs.
	* tree-ssa-loop-niter.h (free_loop_control_ivs): New.

	gcc/testsuite/ChangeLog
	PR tree-optimization/48052
	* gcc.dg/tree-ssa/scev-8.c: New.
	* gcc.dg/tree-ssa/scev-9.c: New.
	* gcc.dg/tree-ssa/scev-10.c: New.
	* gcc.dg/vect/pr48052.c: New.

From-SVN: r224020