[turbofan] Run value numbering as part of typed lowering.

We can already benefit from value numbering (pure) nodes at this point
in the graph, because it makes some later passes more efficient and
reduces the graph size early.

R=jarin@chromium.org

Review-Url: https://codereview.chromium.org/2125613002
Cr-Commit-Position: refs/heads/master@{#37523}

src/compiler/pipeline.cc

@@ -900,6 +900,7 @@ struct TypedLoweringPhase {
         data->info()->is_deoptimization_enabled()
             ? JSIntrinsicLowering::kDeoptimizationEnabled
             : JSIntrinsicLowering::kDeoptimizationDisabled);
+    ValueNumberingReducer value_numbering(temp_zone);
     SimplifiedOperatorReducer simple_reducer(&graph_reducer, data->jsgraph());
     CheckpointElimination checkpoint_elimination(&graph_reducer);
     CommonOperatorReducer common_reducer(&graph_reducer, data->graph(),
@@ -912,6 +913,7 @@ struct TypedLoweringPhase {
     AddReducer(data, &graph_reducer, &typed_lowering);
     AddReducer(data, &graph_reducer, &intrinsic_lowering);
     AddReducer(data, &graph_reducer, &load_elimination);
+    AddReducer(data, &graph_reducer, &value_numbering);
     AddReducer(data, &graph_reducer, &simple_reducer);
     AddReducer(data, &graph_reducer, &checkpoint_elimination);
     AddReducer(data, &graph_reducer, &common_reducer);