This patch replaces the individual stmt_vinfo dr_* fields with
an innermost_loop_behavior, so that the changes in later patches
get picked up automatically.  It also adds a helper function for
getting the behavior of a data reference wrt the vectorised loop.

2017-07-03  Richard Sandiford  <richard.sandiford@linaro.org>

gcc/
	* tree-vectorizer.h (_stmt_vec_info): Replace individual dr_*
	fields with dr_wrt_vec_loop.
	(STMT_VINFO_DR_BASE_ADDRESS, STMT_VINFO_DR_INIT, STMT_VINFO_DR_OFFSET)
	(STMT_VINFO_DR_STEP, STMT_VINFO_DR_ALIGNED_TO): Update accordingly.
	(STMT_VINFO_DR_WRT_VEC_LOOP): New macro.
	(vect_dr_behavior): New function.
	(vect_create_addr_base_for_vector_ref): Remove loop parameter.
	* tree-vect-data-refs.c (vect_compute_data_ref_alignment): Use
	vect_dr_behavior.  Use a step_preserves_misalignment_p boolean to
	track whether the step preserves the misalignment.
	(vect_create_addr_base_for_vector_ref): Remove loop parameter.
	Use vect_dr_behavior.
	(vect_setup_realignment): Update call accordingly.
	(vect_create_data_ref_ptr): Likewise.  Use vect_dr_behavior.
	* tree-vect-loop-manip.c (vect_gen_prolog_loop_niters): Update
	call to vect_create_addr_base_for_vector_ref.
	(vect_create_cond_for_align_checks): Likewise.
	* tree-vect-patterns.c (vect_recog_bool_pattern): Copy
	STMT_VINFO_DR_WRT_VEC_LOOP as a block.
	(vect_recog_mask_conversion_pattern): Likewise.
	* tree-vect-stmts.c (compare_step_with_zero): Use vect_dr_behavior.
	(new_stmt_vec_info): Remove redundant zeroing.

From-SVN: r249911