re PR tree-optimization/26992 (Internal Compiler Error in dwarf2out.c:7607 build_polynomial_chrec)

	PR bootstrap/26992
	* tree-scalar-evolution.c (compute_overall_effect_of_inner_loop,
	chrec_is_positive, set_nb_iterations_in_loop): Use a variable for
	the type of nb_iter.
	(instantiate_parameters_1): Convert the operands before calling
	chrec_fold_minus, chrec_fold_plus, or chrec_fold_multiply.
	* tree-data-ref.c (can_use_analyze_subscript_affine_affine): Same.

From-SVN: r112635