[04/11] Add a vect_orig_stmt helper function

[Richard Sandiford <richard dot sandiford at arm dot com>]

This patch just adds a helper function for going from a potential
pattern statement to the original scalar statement.


2018-07-30  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	* tree-vectorizer.h (vect_orig_stmt): New function.
	* tree-vect-data-refs.c (vect_preserves_scalar_order_p): Use it.
	* tree-vect-loop.c (vect_model_reduction_cost): Likewise.
	(vect_create_epilog_for_reduction): Likewise.
	(vectorizable_live_operation): Likewise.
	* tree-vect-slp.c (vect_find_last_scalar_stmt_in_slp): Likewise.
	(vect_detect_hybrid_slp_stmts, vect_schedule_slp): Likewise.
	* tree-vect-stmts.c (vectorizable_call): Likewise.
	(vectorizable_simd_clone_call, vect_remove_stores): Likewise.

Index: gcc/tree-vectorizer.h
===================================================================
--- gcc/tree-vectorizer.h	2018-07-30 12:32:22.718567174 +0100
+++ gcc/tree-vectorizer.h	2018-07-30 12:32:26.218536339 +0100
@@ -1120,6 +1120,17 @@ is_pattern_stmt_p (stmt_vec_info stmt_in
   return stmt_info->pattern_stmt_p;
 }
 
+/* If STMT_INFO is a pattern statement, return the statement that it
+   replaces, otherwise return STMT_INFO itself.  */
+
+inline stmt_vec_info
+vect_orig_stmt (stmt_vec_info stmt_info)
+{
+  if (is_pattern_stmt_p (stmt_info))
+    return STMT_VINFO_RELATED_STMT (stmt_info);
+  return stmt_info;
+}
+
 /* Return true if BB is a loop header.  */
 
 static inline bool
Index: gcc/tree-vect-data-refs.c
===================================================================
--- gcc/tree-vect-data-refs.c	2018-07-30 12:32:08.934688600 +0100
+++ gcc/tree-vect-data-refs.c	2018-07-30 12:32:26.214536374 +0100
@@ -214,10 +214,8 @@ vect_preserves_scalar_order_p (dr_vec_in
      (but could happen later) while reads will happen no later than their
      current position (but could happen earlier).  Reordering is therefore
      only possible if the first access is a write.  */
-  if (is_pattern_stmt_p (stmtinfo_a))
-    stmtinfo_a = STMT_VINFO_RELATED_STMT (stmtinfo_a);
-  if (is_pattern_stmt_p (stmtinfo_b))
-    stmtinfo_b = STMT_VINFO_RELATED_STMT (stmtinfo_b);
+  stmtinfo_a = vect_orig_stmt (stmtinfo_a);
+  stmtinfo_b = vect_orig_stmt (stmtinfo_b);
   stmt_vec_info earlier_stmt_info = get_earlier_stmt (stmtinfo_a, stmtinfo_b);
   return !DR_IS_WRITE (STMT_VINFO_DATA_REF (earlier_stmt_info));
 }
Index: gcc/tree-vect-loop.c
===================================================================
--- gcc/tree-vect-loop.c	2018-07-30 12:32:22.714567210 +0100
+++ gcc/tree-vect-loop.c	2018-07-30 12:32:26.214536374 +0100
@@ -3814,10 +3814,7 @@ vect_model_reduction_cost (stmt_vec_info
 
   vectype = STMT_VINFO_VECTYPE (stmt_info);
   mode = TYPE_MODE (vectype);
-  stmt_vec_info orig_stmt_info = STMT_VINFO_RELATED_STMT (stmt_info);
-
-  if (!orig_stmt_info)
-    orig_stmt_info = stmt_info;
+  stmt_vec_info orig_stmt_info = vect_orig_stmt (stmt_info);
 
   code = gimple_assign_rhs_code (orig_stmt_info->stmt);
 
@@ -4738,13 +4735,8 @@ vect_create_epilog_for_reduction (vec<tr
          Otherwise (it is a regular reduction) - the tree-code and scalar-def
          are taken from STMT.  */
 
-  stmt_vec_info orig_stmt_info = STMT_VINFO_RELATED_STMT (stmt_info);
-  if (!orig_stmt_info)
-    {
-      /* Regular reduction  */
-      orig_stmt_info = stmt_info;
-    }
-  else
+  stmt_vec_info orig_stmt_info = vect_orig_stmt (stmt_info);
+  if (orig_stmt_info != stmt_info)
     {
       /* Reduction pattern  */
       gcc_assert (STMT_VINFO_IN_PATTERN_P (orig_stmt_info));
@@ -5540,11 +5532,7 @@ vect_create_epilog_for_reduction (vec<tr
   if (REDUC_GROUP_FIRST_ELEMENT (stmt_info))
     {
       stmt_vec_info dest_stmt_info
-	= SLP_TREE_SCALAR_STMTS (slp_node)[group_size - 1];
-      /* Handle reduction patterns.  */
-      if (STMT_VINFO_RELATED_STMT (dest_stmt_info))
-	dest_stmt_info = STMT_VINFO_RELATED_STMT (dest_stmt_info);
-
+	= vect_orig_stmt (SLP_TREE_SCALAR_STMTS (slp_node)[group_size - 1]);
       scalar_dest = gimple_assign_lhs (dest_stmt_info->stmt);
       group_size = 1;
     }
@@ -7898,10 +7886,8 @@ vectorizable_live_operation (stmt_vec_in
       return true;
     }
 
-  /* If stmt has a related stmt, then use that for getting the lhs.  */
-  gimple *stmt = (is_pattern_stmt_p (stmt_info)
-		  ? STMT_VINFO_RELATED_STMT (stmt_info)->stmt
-		  : stmt_info->stmt);
+  /* Use the lhs of the original scalar statement.  */
+  gimple *stmt = vect_orig_stmt (stmt_info)->stmt;
 
   lhs = (is_a <gphi *> (stmt)) ? gimple_phi_result (stmt)
 	: gimple_get_lhs (stmt);
Index: gcc/tree-vect-slp.c
===================================================================
--- gcc/tree-vect-slp.c	2018-07-30 12:32:22.714567210 +0100
+++ gcc/tree-vect-slp.c	2018-07-30 12:32:26.218536339 +0100
@@ -1848,8 +1848,7 @@ vect_find_last_scalar_stmt_in_slp (slp_t
 
   for (int i = 0; SLP_TREE_SCALAR_STMTS (node).iterate (i, &stmt_vinfo); i++)
     {
-      if (is_pattern_stmt_p (stmt_vinfo))
-	stmt_vinfo = STMT_VINFO_RELATED_STMT (stmt_vinfo);
+      stmt_vinfo = vect_orig_stmt (stmt_vinfo);
       last = last ? get_later_stmt (stmt_vinfo, last) : stmt_vinfo;
     }
 
@@ -2314,10 +2313,7 @@ vect_detect_hybrid_slp_stmts (slp_tree n
       gcc_checking_assert (PURE_SLP_STMT (stmt_vinfo));
       /* If we get a pattern stmt here we have to use the LHS of the
          original stmt for immediate uses.  */
-      gimple *stmt = stmt_vinfo->stmt;
-      if (! STMT_VINFO_IN_PATTERN_P (stmt_vinfo)
-	  && STMT_VINFO_RELATED_STMT (stmt_vinfo))
-	stmt = STMT_VINFO_RELATED_STMT (stmt_vinfo)->stmt;
+      gimple *stmt = vect_orig_stmt (stmt_vinfo)->stmt;
       tree def;
       if (gimple_code (stmt) == GIMPLE_PHI)
 	def = gimple_phi_result (stmt);
@@ -4087,8 +4083,7 @@ vect_schedule_slp (vec_info *vinfo)
 	  if (!STMT_VINFO_DATA_REF (store_info))
 	    break;
 
-	  if (is_pattern_stmt_p (store_info))
-	    store_info = STMT_VINFO_RELATED_STMT (store_info);
+	  store_info = vect_orig_stmt (store_info);
 	  /* Free the attached stmt_vec_info and remove the stmt.  */
 	  vinfo->remove_stmt (store_info);
         }
Index: gcc/tree-vect-stmts.c
===================================================================
--- gcc/tree-vect-stmts.c	2018-07-30 12:32:22.718567174 +0100
+++ gcc/tree-vect-stmts.c	2018-07-30 12:32:26.218536339 +0100
@@ -3628,8 +3628,7 @@ vectorizable_call (stmt_vec_info stmt_in
   if (slp_node)
     return true;
 
-  if (is_pattern_stmt_p (stmt_info))
-    stmt_info = STMT_VINFO_RELATED_STMT (stmt_info);
+  stmt_info = vect_orig_stmt (stmt_info);
   lhs = gimple_get_lhs (stmt_info->stmt);
 
   gassign *new_stmt
@@ -4364,10 +4363,7 @@ vectorizable_simd_clone_call (stmt_vec_i
   if (scalar_dest)
     {
       type = TREE_TYPE (scalar_dest);
-      if (is_pattern_stmt_p (stmt_info))
-	lhs = gimple_call_lhs (STMT_VINFO_RELATED_STMT (stmt_info)->stmt);
-      else
-	lhs = gimple_call_lhs (stmt);
+      lhs = gimple_call_lhs (vect_orig_stmt (stmt_info)->stmt);
       new_stmt = gimple_build_assign (lhs, build_zero_cst (type));
     }
   else
@@ -9843,8 +9839,7 @@ vect_remove_stores (stmt_vec_info first_
   while (next_stmt_info)
     {
       stmt_vec_info tmp = DR_GROUP_NEXT_ELEMENT (next_stmt_info);
-      if (is_pattern_stmt_p (next_stmt_info))
-	next_stmt_info = STMT_VINFO_RELATED_STMT (next_stmt_info);
+      next_stmt_info = vect_orig_stmt (next_stmt_info);
       /* Free the attached stmt_vec_info and remove the stmt.  */
       vinfo->remove_stmt (next_stmt_info);
       next_stmt_info = tmp;