[5/n] PR85694: Remove dead WIDEN_SUM handling

vect_recog_dot_prod_pattern and vect_recog_sad_pattern both checked
whether the statement passed in had already been recognised as a
WIDEN_SUM_EXPR pattern.  That isn't possible (any more?), since the
first recognised pattern wins, and since vect_recog_widen_sum_pattern
never matches a later statement than the one it's given.

2018-06-20  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	* tree-vect-patterns.c (vect_recog_dot_prod_pattern): Remove
	redundant WIDEN_SUM_EXPR handling.
	(vect_recog_sad_pattern): Likewise.

From-SVN: r261788

gcc/ChangeLog

 2018-06-20  Richard Sandiford  <richard.sandiford@arm.com>
 
 	* tree-vect-patterns.c (vect_recog_dot_prod_pattern): Remove
+	redundant WIDEN_SUM_EXPR handling.
+	(vect_recog_sad_pattern): Likewise.
+
+2018-06-20  Richard Sandiford  <richard.sandiford@arm.com>
+
+	* tree-vect-patterns.c (vect_recog_dot_prod_pattern): Remove
 	redundant check that the types of a PLUS_EXPR or MULT_EXPR agree.
 	(vect_recog_sad_pattern): Likewise PLUS_EXPR, ABS_EXPR and MINUS_EXPR.
 	(vect_recog_widen_mult_pattern): Likewise MULT_EXPR.

gcc/tree-vect-patterns.c

@@ -339,37 +339,25 @@ vect_recog_dot_prod_pattern (vec<gimple *> *stmts, tree *type_in,
     return NULL;
 
   if (STMT_VINFO_IN_PATTERN_P (stmt_vinfo))
-    {
-      /* Has been detected as widening-summation?  */
+    return NULL;
 
-      stmt = STMT_VINFO_RELATED_STMT (stmt_vinfo);
-      type = gimple_expr_type (stmt);
-      if (gimple_assign_rhs_code (stmt) != WIDEN_SUM_EXPR)
-        return NULL;
-      oprnd0 = gimple_assign_rhs1 (stmt);
-      oprnd1 = gimple_assign_rhs2 (stmt);
-      half_type = TREE_TYPE (oprnd0);
-    }
-  else
-    {
-      gimple *def_stmt;
+  if (!vect_reassociating_reduction_p (stmt_vinfo))
+    return NULL;
 
-      if (!vect_reassociating_reduction_p (stmt_vinfo))
-	return NULL;
-      oprnd0 = gimple_assign_rhs1 (last_stmt);
-      oprnd1 = gimple_assign_rhs2 (last_stmt);
-      stmt = last_stmt;
+  oprnd0 = gimple_assign_rhs1 (last_stmt);
+  oprnd1 = gimple_assign_rhs2 (last_stmt);
+  stmt = last_stmt;
 
-      if (type_conversion_p (oprnd0, stmt, true, &half_type, &def_stmt,
-			     &promotion)
-	  && promotion)
-        {
-          stmt = def_stmt;
-          oprnd0 = gimple_assign_rhs1 (stmt);
-        }
-      else
-        half_type = type;
+  gimple *def_stmt;
+  if (type_conversion_p (oprnd0, stmt, true, &half_type, &def_stmt,
+			 &promotion)
+      && promotion)
+    {
+      stmt = def_stmt;
+      oprnd0 = gimple_assign_rhs1 (stmt);
     }
+  else
+    half_type = type;
 
   /* So far so good.  Since last_stmt was detected as a (summation) reduction,
      we know that oprnd1 is the reduction variable (defined by a loop-header
@@ -553,34 +541,22 @@ vect_recog_sad_pattern (vec<gimple *> *stmts, tree *type_in,
   tree plus_oprnd0, plus_oprnd1;
 
   if (STMT_VINFO_IN_PATTERN_P (stmt_vinfo))
-    {
-      /* Has been detected as widening-summation?  */
+    return NULL;
 
-      gimple *stmt = STMT_VINFO_RELATED_STMT (stmt_vinfo);
-      sum_type = gimple_expr_type (stmt);
-      if (gimple_assign_rhs_code (stmt) != WIDEN_SUM_EXPR)
-        return NULL;
-      plus_oprnd0 = gimple_assign_rhs1 (stmt);
-      plus_oprnd1 = gimple_assign_rhs2 (stmt);
-      half_type = TREE_TYPE (plus_oprnd0);
-    }
-  else
-    {
-      gimple *def_stmt;
+  if (!vect_reassociating_reduction_p (stmt_vinfo))
+    return NULL;
 
-      if (!vect_reassociating_reduction_p (stmt_vinfo))
-	return NULL;
-      plus_oprnd0 = gimple_assign_rhs1 (last_stmt);
-      plus_oprnd1 = gimple_assign_rhs2 (last_stmt);
-
-      /* The type conversion could be promotion, demotion,
-         or just signed -> unsigned.  */
-      if (type_conversion_p (plus_oprnd0, last_stmt, false,
-                             &half_type, &def_stmt, &promotion))
-        plus_oprnd0 = gimple_assign_rhs1 (def_stmt);
-      else
-        half_type = sum_type;
-    }
+  plus_oprnd0 = gimple_assign_rhs1 (last_stmt);
+  plus_oprnd1 = gimple_assign_rhs2 (last_stmt);
+
+  /* The type conversion could be promotion, demotion,
+     or just signed -> unsigned.  */
+  gimple *def_stmt;
+  if (type_conversion_p (plus_oprnd0, last_stmt, false,
+			 &half_type, &def_stmt, &promotion))
+    plus_oprnd0 = gimple_assign_rhs1 (def_stmt);
+  else
+    half_type = sum_type;
 
   /* So far so good.  Since last_stmt was detected as a (summation) reduction,
      we know that plus_oprnd1 is the reduction variable (defined by a loop-header
@@ -639,7 +615,6 @@ vect_recog_sad_pattern (vec<gimple *> *stmts, tree *type_in,
     return NULL;
 
   tree half_type0, half_type1;
-  gimple *def_stmt;
 
   tree minus_oprnd0 = gimple_assign_rhs1 (diff_stmt);
   tree minus_oprnd1 = gimple_assign_rhs2 (diff_stmt);