[4/7] Add a gather_scatter_info structure

This patch just refactors the gather/scatter support so that all
information is in a single structure, rather than separate variables.
This reduces the number of arguments to a function added in patch 6.

Tested on aarch64-linux-gnu and x86_64-linux-gnu.

gcc/
	* tree-vectorizer.h (gather_scatter_info): New structure.
	(vect_check_gather_scatter): Return a bool rather than a decl.
	Replace return-by-pointer arguments with a single
	gather_scatter_info *.
	* tree-vect-data-refs.c (vect_check_gather_scatter): Likewise.
	(vect_analyze_data_refs): Update call accordingly.
	* tree-vect-stmts.c (vect_mark_stmts_to_be_vectorized): Likewise.
	(vectorizable_mask_load_store): Likewise.  Also record the
	offset dt and vectype in the gather_scatter_info.
	(vectorizable_store): Likewise.
	(vectorizable_load): Likewise.

From-SVN: r238036

gcc/ChangeLog

 2016-07-06  Richard Sandiford  <richard.sandiford@arm.com>
 
+	* tree-vectorizer.h (gather_scatter_info): New structure.
+	(vect_check_gather_scatter): Return a bool rather than a decl.
+	Replace return-by-pointer arguments with a single
+	gather_scatter_info *.
+	* tree-vect-data-refs.c (vect_check_gather_scatter): Likewise.
+	(vect_analyze_data_refs): Update call accordingly.
+	* tree-vect-stmts.c (vect_mark_stmts_to_be_vectorized): Likewise.
+	(vectorizable_mask_load_store): Likewise.  Also record the
+	offset dt and vectype in the gather_scatter_info.
+	(vectorizable_store): Likewise.
+	(vectorizable_load): Likewise.
+
+2016-07-06  Richard Sandiford  <richard.sandiford@arm.com>
+
 	* tree-vect-stmts.c (vect_model_store_cost): For non-SLP
 	strided groups, use the cost of N scalar accesses instead
 	of ncopies vector accesses.

gcc/tree-vect-data-refs.c

@@ -3187,12 +3187,12 @@ vect_prune_runtime_alias_test_list (loop_vec_info loop_vinfo)
   return true;
 }
 
-/* Check whether a non-affine read or write in stmt is suitable for gather load
-   or scatter store and if so, return a builtin decl for that operation.  */
+/* Return true if a non-affine read or write in STMT is suitable for a
+   gather load or scatter store.  Describe the operation in *INFO if so.  */
 
-tree
-vect_check_gather_scatter (gimple *stmt, loop_vec_info loop_vinfo, tree *basep,
-			   tree *offp, int *scalep)
+bool
+vect_check_gather_scatter (gimple *stmt, loop_vec_info loop_vinfo,
+			   gather_scatter_info *info)
 {
   HOST_WIDE_INT scale = 1, pbitpos, pbitsize;
   struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
@@ -3266,7 +3266,7 @@ vect_check_gather_scatter (gimple *stmt, loop_vec_info loop_vinfo, tree *basep,
   if (!expr_invariant_in_loop_p (loop, base))
     {
       if (!integer_zerop (off))
-	return NULL_TREE;
+	return false;
       off = base;
       base = size_int (pbitpos / BITS_PER_UNIT);
     }
@@ -3292,7 +3292,7 @@ vect_check_gather_scatter (gimple *stmt, loop_vec_info loop_vinfo, tree *basep,
 	  gimple *def_stmt = SSA_NAME_DEF_STMT (off);
 
 	  if (expr_invariant_in_loop_p (loop, off))
-	    return NULL_TREE;
+	    return false;
 
 	  if (gimple_code (def_stmt) != GIMPLE_ASSIGN)
 	    break;
@@ -3304,7 +3304,7 @@ vect_check_gather_scatter (gimple *stmt, loop_vec_info loop_vinfo, tree *basep,
       else
 	{
 	  if (get_gimple_rhs_class (TREE_CODE (off)) == GIMPLE_TERNARY_RHS)
-	    return NULL_TREE;
+	    return false;
 	  code = TREE_CODE (off);
 	  extract_ops_from_tree (off, &code, &op0, &op1);
 	}
@@ -3379,7 +3379,7 @@ vect_check_gather_scatter (gimple *stmt, loop_vec_info loop_vinfo, tree *basep,
      defined in the loop, punt.  */
   if (TREE_CODE (off) != SSA_NAME
       || expr_invariant_in_loop_p (loop, off))
-    return NULL_TREE;
+    return false;
 
   if (offtype == NULL_TREE)
     offtype = TREE_TYPE (off);
@@ -3392,15 +3392,15 @@ vect_check_gather_scatter (gimple *stmt, loop_vec_info loop_vinfo, tree *basep,
 					      offtype, scale);
 
   if (decl == NULL_TREE)
-    return NULL_TREE;
-
-  if (basep)
-    *basep = base;
-  if (offp)
-    *offp = off;
-  if (scalep)
-    *scalep = scale;
-  return decl;
+    return false;
+
+  info->decl = decl;
+  info->base = base;
+  info->offset = off;
+  info->offset_dt = vect_unknown_def_type;
+  info->offset_vectype = NULL_TREE;
+  info->scale = scale;
+  return true;
 }
 
 /* Function vect_analyze_data_refs.
@@ -3878,10 +3878,10 @@ again:
 
       if (gatherscatter != SG_NONE)
 	{
-	  tree off;
+	  gather_scatter_info gs_info;
 	  if (!vect_check_gather_scatter (stmt, as_a <loop_vec_info> (vinfo),
-					  NULL, &off, NULL)
-	      || get_vectype_for_scalar_type (TREE_TYPE (off)) == NULL_TREE)
+					  &gs_info)
+	      || !get_vectype_for_scalar_type (TREE_TYPE (gs_info.offset)))
 	    {
 	      STMT_VINFO_DATA_REF (stmt_info) = NULL;
 	      free_data_ref (dr);

gcc/tree-vectorizer.h

@@ -608,6 +608,28 @@ typedef struct _stmt_vec_info {
   unsigned int num_slp_uses;
 } *stmt_vec_info;
 
+/* Information about a gather/scatter call.  */
+struct gather_scatter_info {
+  /* The FUNCTION_DECL for the built-in gather/scatter function.  */
+  tree decl;
+
+  /* The loop-invariant base value.  */
+  tree base;
+
+  /* The original scalar offset, which is a non-loop-invariant SSA_NAME.  */
+  tree offset;
+
+  /* Each offset element should be multiplied by this amount before
+     being added to the base.  */
+  int scale;
+
+  /* The definition type for the vectorized offset.  */
+  enum vect_def_type offset_dt;
+
+  /* The type of the vectorized offset.  */
+  tree offset_vectype;
+};
+
 /* Access Functions.  */
 #define STMT_VINFO_TYPE(S)                 (S)->type
 #define STMT_VINFO_STMT(S)                 (S)->stmt
@@ -1031,8 +1053,8 @@ extern bool vect_verify_datarefs_alignment (loop_vec_info);
 extern bool vect_slp_analyze_and_verify_instance_alignment (slp_instance);
 extern bool vect_analyze_data_ref_accesses (vec_info *);
 extern bool vect_prune_runtime_alias_test_list (loop_vec_info);
-extern tree vect_check_gather_scatter (gimple *, loop_vec_info, tree *, tree *,
-				       int *);
+extern bool vect_check_gather_scatter (gimple *, loop_vec_info,
+				       gather_scatter_info *);
 extern bool vect_analyze_data_refs (vec_info *, int *);
 extern tree vect_create_data_ref_ptr (gimple *, tree, struct loop *, tree,
 				      tree *, gimple_stmt_iterator *,