guard maybe_set_vectorized_backedge_value calls

This makes sure to not call maybe_set_vectorized_backedge_value when
we did not vectorize the latch def candidate.

2020-12-02  Richard Biener  <rguenther@suse.de>

	* tree-vect-loop.c (vect_transform_loop_stmt): Return whether
	we vectorized a stmt.
	(vect_transform_loop): Only call maybe_set_vectorized_backedge_value
	when we vectorized the stmt.

diff --git a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c
index c8b4dc3a0c30ac20e6e0926b791c47f49b2f0445..72bbec4b45d225d73eddfaca69468cd23842a42a 100644 (file)
--- a/gcc/tree-vect-loop.c
+++ b/gcc/tree-vect-loop.c
@@ -9081,7 +9081,7 @@ maybe_set_vectorized_backedge_value (loop_vec_info loop_vinfo,
    When vectorizing STMT_INFO as a store, set *SEEN_STORE to its
    stmt_vec_info.  */
 
-static void
+static bool
 vect_transform_loop_stmt (loop_vec_info loop_vinfo, stmt_vec_info stmt_info,
                          gimple_stmt_iterator *gsi, stmt_vec_info *seen_store)
 {
@@ -9097,7 +9097,7 @@ vect_transform_loop_stmt (loop_vec_info loop_vinfo, stmt_vec_info stmt_info,
 
   if (!STMT_VINFO_RELEVANT_P (stmt_info)
       && !STMT_VINFO_LIVE_P (stmt_info))
-    return;
+    return false;
 
   if (STMT_VINFO_VECTYPE (stmt_info))
     {
@@ -9114,13 +9114,15 @@ vect_transform_loop_stmt (loop_vec_info loop_vinfo, stmt_vec_info stmt_info,
   /* Pure SLP statements have already been vectorized.  We still need
      to apply loop vectorization to hybrid SLP statements.  */
   if (PURE_SLP_STMT (stmt_info))
-    return;
+    return false;
 
   if (dump_enabled_p ())
     dump_printf_loc (MSG_NOTE, vect_location, "transform statement.\n");
 
   if (vect_transform_stmt (loop_vinfo, stmt_info, gsi, NULL, NULL))
     *seen_store = stmt_info;
+
+  return true;
 }
 
 /* Helper function to pass to simplify_replace_tree to enable replacing tree's
@@ -9546,17 +9548,17 @@ vect_transform_loop (loop_vec_info loop_vinfo, gimple *loop_vectorized_call)
                        }
                      stmt_vec_info pat_stmt_info
                        = STMT_VINFO_RELATED_STMT (stmt_info);
-                     vect_transform_loop_stmt (loop_vinfo, pat_stmt_info, &si,
-                                               &seen_store);
-                     maybe_set_vectorized_backedge_value (loop_vinfo,
-                                                          pat_stmt_info);
+                     if (vect_transform_loop_stmt (loop_vinfo, pat_stmt_info,
+                                                   &si, &seen_store))
+                       maybe_set_vectorized_backedge_value (loop_vinfo,
+                                                            pat_stmt_info);
                    }
                  else
                    {
-                     vect_transform_loop_stmt (loop_vinfo, stmt_info, &si,
-                                               &seen_store);
-                     maybe_set_vectorized_backedge_value (loop_vinfo,
-                                                          stmt_info);
+                     if (vect_transform_loop_stmt (loop_vinfo, stmt_info, &si,
+                                                   &seen_store))
+                       maybe_set_vectorized_backedge_value (loop_vinfo,
+                                                            stmt_info);
                    }
                }
              gsi_next (&si);