Move simplification of statements using ranges into its own class.

Move simplification of statements using ranges into its own class.

This moves all the simplification code from vr_values into a separate
class (simplify_using_ranges).  In doing so, we get rid of a bunch of
dependencies on the internals of vr_values.  The goal is to (a) remove
unnecessary interdependendcies (b) be able to use this engine with any
range infrastructure, as all it needs is a method to get the range for
an SSA name (get_value_range).

I also removed as many dependencies on value_range_equiv as possible,
preferring value_range.  A few value_range_equiv uses remain, but for
cases where equivalences are actually used (folding conditionals, etc).

gcc/ChangeLog:

	* gimple-ssa-evrp-analyze.h (vrp_visit_cond_stmt): Use
	simplify_using_ranges class.
	* gimple-ssa-evrp.c (class evrp_folder): New simplify_using_ranges
	field.  Adjust all methods to use new field.
	* tree-ssa-dom.c (simplify_stmt_for_jump_threading): Use
	simplify_using_ranges class.
	* tree-vrp.c (class vrp_folder): New simplify_using_ranges
	field.  Adjust all methods to use new field.
	(simplify_stmt_for_jump_threading): Use simplify_using_ranges class.
	(vrp_prop::vrp_finalize): New vrp_folder argument.
	(execute_vrp): Pass folder to vrp_finalize.  Use
	simplify_using_ranges class.
	Remove cleanup_edges_and_switches call.
	* vr-values.c (vr_values::op_with_boolean_value_range_p): Change
	value_range_equiv uses to value_range.
	(simplify_using_ranges::op_with_boolean_value_range_p): Use
	simplify_using_ranges class.
	(check_for_binary_op_overflow): Make static.
	(vr_values::extract_range_basic): Pass this to
	check_for_binary_op_overflow.
	(compare_range_with_value): Change value_range_equiv uses to
	value_range.
	(vr_values::vr_values): Initialize simplifier field.
	Remove uses of to_remove_edges and to_update_switch_stmts.
	(vr_values::~vr_values): Remove uses of to_remove_edges and
	to_update_switch_stmts.
	(vr_values::get_vr_for_comparison): Move to simplify_using_ranges
	class.
	(vr_values::compare_name_with_value): Same.
	(vr_values::compare_names): Same.
	(vr_values::vrp_evaluate_conditional_warnv_with_ops): Same.
	(vr_values::vrp_evaluate_conditional): Same.
	(vr_values::vrp_visit_cond_stmt): Same.
	(find_case_label_ranges): Change value_range_equiv uses to
	value_range.
	(vr_values::extract_range_from_stmt): Use simplify_using_ranges class.
	(vr_values::simplify_truth_ops_using_ranges): Move to
	simplify_using_ranges class.
	(vr_values::simplify_div_or_mod_using_ranges): Same.
	(vr_values::simplify_min_or_max_using_ranges): Same.
	(vr_values::simplify_abs_using_ranges): Same.
	(vr_values::simplify_bit_ops_using_ranges): Same.
	(test_for_singularity): Change value_range_equiv uses to
	value_range.
	(range_fits_type_p): Same.
	(vr_values::simplify_cond_using_ranges_1): Same.
	(vr_values::simplify_cond_using_ranges_2): Make extern.
	(vr_values::fold_cond): Move to simplify_using_ranges class.
	(vr_values::simplify_switch_using_ranges): Same.
	(vr_values::cleanup_edges_and_switches): Same.
	(vr_values::simplify_float_conversion_using_ranges): Same.
	(vr_values::simplify_internal_call_using_ranges): Same.
	(vr_values::two_valued_val_range_p): Same.
	(vr_values::simplify_stmt_using_ranges): Move to...
	(simplify_using_ranges::simplify): ...here.
	* vr-values.h (class vr_values): Move all the simplification of
	statements using ranges methods and code from here...
	(class simplify_using_ranges): ...to here.
	(simplify_cond_using_ranges_2): New extern prototype.