tree-optimization/98758 - fix integer arithmetic in data-ref analysis

tree-optimization/98758 - fix integer arithmetic in data-ref analysis

This fixes some int arithmetic issues and a bogus truncation.

2021-01-20  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/98758
	* tree-data-ref.c (int_divides_p): Use lambda_int arguments.
	(lambda_matrix_right_hermite): Avoid undefinedness with
	signed integer abs and multiplication.
	(analyze_subscript_affine_affine): Use lambda_int.

	* gcc.dg/torture/pr98758.c: New testcase.

(cherry picked from commit 34599780d0de72faf5719ea08d11a061722b9d19)