A later patch adds base alignment information to innermost_loop_behavior.
After that, the only remaining piece of alignment information that wasn't
immediately obvious was the step alignment. Adding that allows a minor
simplification to vect_compute_data_ref_alignment, and also potentially
improves the handling of variable strides for outer loop vectorisation.
A later patch will also use it to give the alignment of the DR as a whole.
2017-07-03 Richard Sandiford <richard.sandiford@linaro.org>
gcc/
* tree-data-ref.h (innermost_loop_behavior): Add a step_alignment
field.
(DR_STEP_ALIGNMENT): New macro.
* tree-vectorizer.h (STMT_VINFO_DR_STEP_ALIGNMENT): Likewise.
* tree-data-ref.c (dr_analyze_innermost): Initalize step_alignment.
(create_data_ref): Print it.
* tree-vect-stmts.c (vectorizable_load): Use the step alignment
to tell whether the step preserves vector (mis)alignment.
* tree-vect-data-refs.c (vect_compute_data_ref_alignment): Likewise.
Move the check for an integer step and generalise to all INTEGER_CST.
(vect_analyze_data_refs): Set DR_STEP_ALIGNMENT when setting DR_STEP.
Print the outer step alignment.
From-SVN: r249915
