Add a vect_get_scalar_dr_size helper function

This patch adds a helper function for getting the number of bytes
accessed by an unvectorised data reference, which helps when general
modes have a variable size.

2017-09-22  Richard Sandiford  <richard.sandiford@linaro.org>
	    Alan Hayward  <alan.hayward@arm.com>
	    David Sherwood  <david.sherwood@arm.com>

gcc/
	* tree-vectorizer.h (vect_get_scalar_dr_size): New function.
	* tree-vect-data-refs.c (vect_update_misalignment_for_peel): Use it.
	(vect_enhance_data_refs_alignment): Likewise.

Co-Authored-By: Alan Hayward <alan.hayward@arm.com>
Co-Authored-By: David Sherwood <david.sherwood@arm.com>

From-SVN: r253099

1 files changed, 13 insertions, 0 deletions

diff --git a/gcc/tree-vectorizer.h b/gcc/tree-vectorizer.h
index d6753ff..5d273ca 100644
--- a/gcc/tree-vectorizer.h
+++ b/gcc/tree-vectorizer.h
@@ -1095,6 +1095,19 @@ vect_get_num_copies (loop_vec_info loop_vinfo, tree vectype)
 	  / TYPE_VECTOR_SUBPARTS (vectype));
 }
 
+/* Return the size of the value accessed by unvectorized data reference DR.
+   This is only valid once STMT_VINFO_VECTYPE has been calculated for the
+   associated gimple statement, since that guarantees that DR accesses
+   either a scalar or a scalar equivalent.  ("Scalar equivalent" here
+   includes things like V1SI, which can be vectorized in the same way
+   as a plain SI.)  */
+
+inline unsigned int
+vect_get_scalar_dr_size (struct data_reference *dr)
+{
+  return tree_to_uhwi (TYPE_SIZE_UNIT (TREE_TYPE (DR_REF (dr))));
+}
+
 /* Source location */
 extern source_location vect_location;