[05/11] Add a vect_stmt_to_vectorize helper function

This patch adds a helper that does the opposite of vect_orig_stmt:
go from the original scalar statement to the statement that should
actually be vectorised.

The use in the last two hunks of vectorizable_reduction are because
reduc_stmt_info (first hunk) and stmt_info (second hunk) are already
pattern statements if appropriate.

2018-08-01  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	* tree-vectorizer.h (vect_stmt_to_vectorize): New function.
	* tree-vect-loop.c (vect_update_vf_for_slp): Use it.
	(vectorizable_reduction): Likewise.
	* tree-vect-slp.c (vect_analyze_slp_instance): Likewise.
	(vect_detect_hybrid_slp_stmts): Likewise.
	* tree-vect-stmts.c (vect_is_simple_use): Likewise.

From-SVN: r263219

gcc/ChangeLog

+2018-08-01  Richard Sandiford  <richard.sandiford@arm.com>
+
+	* tree-vectorizer.h (vect_stmt_to_vectorize): New function.
+	* tree-vect-loop.c (vect_update_vf_for_slp): Use it.
+	(vectorizable_reduction): Likewise.
+	* tree-vect-slp.c (vect_analyze_slp_instance): Likewise.
+	(vect_detect_hybrid_slp_stmts): Likewise.
+	* tree-vect-stmts.c (vect_is_simple_use): Likewise.
+
 2018-08-01  Aldy Hernandez  <aldyh@redhat.com>
 
 	* tree-vrp (zero_nonzero_bits_from_bounds): Rename to...

gcc/tree-vect-loop.c

@@ -1424,9 +1424,7 @@ vect_update_vf_for_slp (loop_vec_info loop_vinfo)
 	   gsi_next (&si))
 	{
 	  stmt_vec_info stmt_info = loop_vinfo->lookup_stmt (gsi_stmt (si));
-	  if (STMT_VINFO_IN_PATTERN_P (stmt_info)
-	      && STMT_VINFO_RELATED_STMT (stmt_info))
-	    stmt_info = STMT_VINFO_RELATED_STMT (stmt_info);
+	  stmt_info = vect_stmt_to_vectorize (stmt_info);
 	  if ((STMT_VINFO_RELEVANT_P (stmt_info)
 	       || VECTORIZABLE_CYCLE_DEF (STMT_VINFO_DEF_TYPE (stmt_info)))
 	      && !PURE_SLP_STMT (stmt_info))
@@ -6111,8 +6109,7 @@ vectorizable_reduction (stmt_vec_info stmt_info, gimple_stmt_iterator *gsi,
 	return true;
 
       stmt_vec_info reduc_stmt_info = STMT_VINFO_REDUC_DEF (stmt_info);
-      if (STMT_VINFO_IN_PATTERN_P (reduc_stmt_info))
-	reduc_stmt_info = STMT_VINFO_RELATED_STMT (reduc_stmt_info);
+      reduc_stmt_info = vect_stmt_to_vectorize (reduc_stmt_info);
 
       if (STMT_VINFO_VEC_REDUCTION_TYPE (reduc_stmt_info)
 	  == EXTRACT_LAST_REDUCTION)
@@ -6145,8 +6142,7 @@ vectorizable_reduction (stmt_vec_info stmt_info, gimple_stmt_iterator *gsi,
       if (ncopies > 1
 	  && STMT_VINFO_RELEVANT (reduc_stmt_info) <= vect_used_only_live
 	  && (use_stmt_info = loop_vinfo->lookup_single_use (phi_result))
-	  && (use_stmt_info == reduc_stmt_info
-	      || STMT_VINFO_RELATED_STMT (use_stmt_info) == reduc_stmt_info))
+	  && vect_stmt_to_vectorize (use_stmt_info) == reduc_stmt_info)
 	single_defuse_cycle = true;
 
       /* Create the destination vector  */
@@ -6915,8 +6911,7 @@ vectorizable_reduction (stmt_vec_info stmt_info, gimple_stmt_iterator *gsi,
   if (ncopies > 1
       && (STMT_VINFO_RELEVANT (stmt_info) <= vect_used_only_live)
       && (use_stmt_info = loop_vinfo->lookup_single_use (reduc_phi_result))
-      && (use_stmt_info == stmt_info
-	  || STMT_VINFO_RELATED_STMT (use_stmt_info) == stmt_info))
+      && vect_stmt_to_vectorize (use_stmt_info) == stmt_info)
     {
       single_defuse_cycle = true;
       epilog_copies = 1;

gcc/tree-vect-slp.c

@@ -1969,11 +1969,7 @@ vect_analyze_slp_instance (vec_info *vinfo,
       /* Collect the stores and store them in SLP_TREE_SCALAR_STMTS.  */
       while (next_info)
         {
-	  if (STMT_VINFO_IN_PATTERN_P (next_info)
-	      && STMT_VINFO_RELATED_STMT (next_info))
-	    scalar_stmts.safe_push (STMT_VINFO_RELATED_STMT (next_info));
-	  else
-	    scalar_stmts.safe_push (next_info);
+	  scalar_stmts.safe_push (vect_stmt_to_vectorize (next_info));
 	  next_info = DR_GROUP_NEXT_ELEMENT (next_info);
         }
     }
@@ -1983,11 +1979,7 @@ vect_analyze_slp_instance (vec_info *vinfo,
 	 SLP_TREE_SCALAR_STMTS.  */
       while (next_info)
         {
-	  if (STMT_VINFO_IN_PATTERN_P (next_info)
-	      && STMT_VINFO_RELATED_STMT (next_info))
-	    scalar_stmts.safe_push (STMT_VINFO_RELATED_STMT (next_info));
-	  else
-	    scalar_stmts.safe_push (next_info);
+	  scalar_stmts.safe_push (vect_stmt_to_vectorize (next_info));
 	  next_info = REDUC_GROUP_NEXT_ELEMENT (next_info);
         }
       /* Mark the first element of the reduction chain as reduction to properly
@@ -2325,9 +2317,7 @@ vect_detect_hybrid_slp_stmts (slp_tree node, unsigned i, slp_vect_type stype)
 	    use_vinfo = loop_vinfo->lookup_stmt (use_stmt);
 	    if (!use_vinfo)
 	      continue;
-	    if (STMT_VINFO_IN_PATTERN_P (use_vinfo)
-		&& STMT_VINFO_RELATED_STMT (use_vinfo))
-	      use_vinfo = STMT_VINFO_RELATED_STMT (use_vinfo);
+	    use_vinfo = vect_stmt_to_vectorize (use_vinfo);
 	    if (!STMT_SLP_TYPE (use_vinfo)
 		&& (STMT_VINFO_RELEVANT (use_vinfo)
 		    || VECTORIZABLE_CYCLE_DEF (STMT_VINFO_DEF_TYPE (use_vinfo)))

gcc/tree-vect-stmts.c

@@ -10031,11 +10031,8 @@ vect_is_simple_use (tree operand, vec_info *vinfo, enum vect_def_type *dt,
 	*dt = vect_external_def;
       else
 	{
-	  if (STMT_VINFO_IN_PATTERN_P (stmt_vinfo))
-	    {
-	      stmt_vinfo = STMT_VINFO_RELATED_STMT (stmt_vinfo);
-	      def_stmt = stmt_vinfo->stmt;
-	    }
+	  stmt_vinfo = vect_stmt_to_vectorize (stmt_vinfo);
+	  def_stmt = stmt_vinfo->stmt;
 	  switch (gimple_code (def_stmt))
 	    {
 	    case GIMPLE_PHI:

gcc/tree-vectorizer.h

@@ -1131,6 +1131,17 @@ vect_orig_stmt (stmt_vec_info stmt_info)
   return stmt_info;
 }
 
+/* If STMT_INFO has been replaced by a pattern statement, return the
+   replacement statement, otherwise return STMT_INFO itself.  */
+
+inline stmt_vec_info
+vect_stmt_to_vectorize (stmt_vec_info stmt_info)
+{
+  if (STMT_VINFO_IN_PATTERN_P (stmt_info))
+    return STMT_VINFO_RELATED_STMT (stmt_info);
+  return stmt_info;
+}
+
 /* Return true if BB is a loop header.  */
 
 static inline bool