[Bug tree-optimization/23286] missed fully redundant expression

["rguenth at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #28 from rguenth at gcc dot gnu dot org  2010-01-17 12:56 -------
sth like

@@ -3893,7 +3893,29 @@ insert_aux (basic_block block, bool do_p

          /* Insert expressions for hoisting.  */
          if (do_hoist && EDGE_COUNT (block->succs) >= 2)
-           new_stuff |= do_hoist_insertion (block);
+           {
+             edge e;
+             edge_iterator ei;
+
+             new_stuff |= do_hoist_insertion (block);
+
+             /* Immediately update AVAIL_OUT of immediately dominated blocks
+                with the hoisted expressions.  */
+             newset = NEW_SETS (block);
+             if (newset)
+               FOR_EACH_EDGE (e, ei, block->succs)
+                 {
+                   if (EDGE_COUNT (e->dest->preds) != 1)
+                     continue;
+
+                   FOR_EACH_EXPR_ID_IN_SET (newset, i, bi)
+                     {
+                       pre_expr expr = expression_for_id (i);
+                       bitmap_value_replace_in_set (NEW_SETS (e->dest), expr);
+                       bitmap_value_replace_in_set (AVAIL_OUT (e->dest),
expr);
+                     }
+                 }
+           }
        }
     }
   for (son = first_dom_son (CDI_DOMINATORS, block);


on top of the last patch


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23286