VECT: Add tree_code into "creat_iv" and allow it can handle MINUS_EXPR IV

VECT: Add tree_code into "creat_iv" and allow it can handle MINUS_EXPR IV

This patch is going to be commited after bootstrap && regression on X86
PASSED.

Thanks Richards.

gcc/ChangeLog:

	* cfgloopmanip.cc (create_empty_loop_on_edge): Add PLUS_EXPR.
	* gimple-loop-interchange.cc
	(tree_loop_interchange::map_inductions_to_loop): Ditto.
	* tree-ssa-loop-ivcanon.cc (create_canonical_iv): Ditto.
	* tree-ssa-loop-ivopts.cc (create_new_iv): Ditto.
	* tree-ssa-loop-manip.cc (create_iv): Ditto.
	(tree_transform_and_unroll_loop): Ditto.
	(canonicalize_loop_ivs): Ditto.
	* tree-ssa-loop-manip.h (create_iv): Ditto.
	* tree-vect-data-refs.cc (vect_create_data_ref_ptr): Ditto.
	* tree-vect-loop-manip.cc (vect_set_loop_controls_directly):
	Ditto.
	(vect_set_loop_condition_normal): Ditto.
	* tree-vect-loop.cc (vect_create_epilog_for_reduction): Ditto.
	* tree-vect-stmts.cc (vectorizable_store): Ditto.
	(vectorizable_load): Ditto.

Signed-off-by: Juzhe Zhong <juzhe.zhong@rivai.ai>