re PR target/32457 (Complete program optimized away (i686, -ftree-vectorize))

	PR middle-end/32457
	* tree-data-ref.c (analyze_siv_subscript_cst_affine,
	compute_overlap_steps_for_affine_1_2, analyze_subscript_affine_affine,
	init_omega_for_ddr_1): Use non conservative number of iterations
	estimations.
	(analyze_subscript_affine_affine): Use HOST_WIDE_INT instead of int.
	(analyze_siv_subscript): Remove FIXME and reinitialization of 
	last_conflicts to chrec_dont_know.
	* testsuite/gfortran.dg/vect/pr32457.f90: New.

From-SVN: r126305