Invoke vectorizable_live_operation in a consistent way

vect_transform_stmt calls vectorizable_live_operation for
each live statement in an SLP node, but vect_analyze_stmt
only called it the once.  This patch makes vect_analyze_stmt
consistent with vect_transform_stmt, which should be a bit
more robust, and also means that a later patch can use
slp_index when deciding validity.

2017-09-18  Richard Sandiford  <richard.sandiford@linaro.org>
	    Alan Hayward  <alan.hayward@arm.com>
	    David Sherwood  <david.sherwood@arm.com>

gcc/
	* tree-vect-stmts.c (can_vectorize_live_stmts): New function,
	split out from...
	(vect_transform_stmt): ...here.
	(vect_analyze_stmt): Use it instead of calling
	vectorizable_live_operation directly.

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

From-SVN: r252929

gcc/ChangeLog

+2017-09-18  Richard Sandiford  <richard.sandiford@linaro.org>
+	    Alan Hayward  <alan.hayward@arm.com>
+	    David Sherwood  <david.sherwood@arm.com>
+
+	* tree-vect-stmts.c (can_vectorize_live_stmts): New function,
+	split out from...
+	(vect_transform_stmt): ...here.
+	(vect_analyze_stmt): Use it instead of calling
+	vectorizable_live_operation directly.
+
 2017-09-18  Cesar Philippidis  <cesar@codesourcery.com>
 
 	* omp-offload.c (oacc_xform_loop): Enable SIMD vectorization on

gcc/tree-vect-stmts.c

@@ -8479,6 +8479,35 @@ vectorizable_comparison (gimple *stmt, gimple_stmt_iterator *gsi,
   return true;
 }
 
+/* If SLP_NODE is nonnull, return true if vectorizable_live_operation
+   can handle all live statements in the node.  Otherwise return true
+   if STMT is not live or if vectorizable_live_operation can handle it.
+   GSI and VEC_STMT are as for vectorizable_live_operation.  */
+
+static bool
+can_vectorize_live_stmts (gimple *stmt, gimple_stmt_iterator *gsi,
+			  slp_tree slp_node, gimple **vec_stmt)
+{
+  if (slp_node)
+    {
+      gimple *slp_stmt;
+      unsigned int i;
+      FOR_EACH_VEC_ELT (SLP_TREE_SCALAR_STMTS (slp_node), i, slp_stmt)
+	{
+	  stmt_vec_info slp_stmt_info = vinfo_for_stmt (slp_stmt);
+	  if (STMT_VINFO_LIVE_P (slp_stmt_info)
+	      && !vectorizable_live_operation (slp_stmt, gsi, slp_node, i,
+					       vec_stmt))
+	    return false;
+	}
+    }
+  else if (STMT_VINFO_LIVE_P (vinfo_for_stmt (stmt))
+	   && !vectorizable_live_operation (stmt, gsi, slp_node, -1, vec_stmt))
+    return false;
+
+  return true;
+}
+
 /* Make sure the statement is vectorizable.  */
 
 bool
@@ -8685,17 +8714,13 @@ vect_analyze_stmt (gimple *stmt, bool *need_to_vectorize, slp_tree node,
 
   /* Stmts that are (also) "live" (i.e. - that are used out of the loop)
       need extra handling, except for vectorizable reductions.  */
-  if (STMT_VINFO_LIVE_P (stmt_info)
-      && STMT_VINFO_TYPE (stmt_info) != reduc_vec_info_type)
-    ok = vectorizable_live_operation (stmt, NULL, node, -1, NULL);
-
-  if (!ok)
+  if (STMT_VINFO_TYPE (stmt_info) != reduc_vec_info_type
+      && !can_vectorize_live_stmts (stmt, NULL, node, NULL))
     {
       if (dump_enabled_p ())
         {
           dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
-                           "not vectorized: live stmt not ");
-          dump_printf (MSG_MISSED_OPTIMIZATION,  "supported: ");
+                           "not vectorized: live stmt not supported: ");
           dump_gimple_stmt (MSG_MISSED_OPTIMIZATION, TDF_SLIM, stmt, 0);
         }
 
@@ -8861,26 +8886,9 @@ vect_transform_stmt (gimple *stmt, gimple_stmt_iterator *gsi,
 
   /* Handle stmts whose DEF is used outside the loop-nest that is
      being vectorized.  */
-  if (slp_node)
-    {
-      gimple *slp_stmt;
-      int i;
-      if (STMT_VINFO_TYPE (stmt_info) != reduc_vec_info_type)
-	FOR_EACH_VEC_ELT (SLP_TREE_SCALAR_STMTS (slp_node), i, slp_stmt)
-	  {
-	    stmt_vec_info slp_stmt_info = vinfo_for_stmt (slp_stmt);
-	    if (STMT_VINFO_LIVE_P (slp_stmt_info))
-	      {
-		done = vectorizable_live_operation (slp_stmt, gsi, slp_node, i,
-						    &vec_stmt);
-		gcc_assert (done);
-	      }
-	  }
-    }
-  else if (STMT_VINFO_LIVE_P (stmt_info)
-	   && STMT_VINFO_TYPE (stmt_info) != reduc_vec_info_type)
+  if (STMT_VINFO_TYPE (stmt_info) != reduc_vec_info_type)
     {
-      done = vectorizable_live_operation (stmt, gsi, slp_node, -1, &vec_stmt);
+      done = can_vectorize_live_stmts (stmt, gsi, slp_node, &vec_stmt);
       gcc_assert (done);
     }