Revert "[turbofan] Smartify the GraphReducer."

src/compiler/pipeline.cc

Index: src/compiler/pipeline.cc
diff --git a/src/compiler/pipeline.cc b/src/compiler/pipeline.cc
index e4d8c5d46741d416640c3e393774633483219c6d..a05e2b3e382657ebbe83e1e1ed0bdd7e333ad48a 100644
--- a/src/compiler/pipeline.cc
+++ b/src/compiler/pipeline.cc
@@ -386,13 +386,12 @@ Handle<Code> Pipeline::GenerateCode() {
     {
       // Lower JSOperators where we can determine types.
       PhaseScope phase_scope(pipeline_statistics.get(), "typed lowering");
-      ZonePool::Scope zone_scope(data.zone_pool());
       SourcePositionTable::Scope pos(data.source_positions(),
                                      SourcePosition::Unknown());
       ValueNumberingReducer vn_reducer(data.graph_zone());
       JSTypedLowering lowering(data.jsgraph());
       SimplifiedOperatorReducer simple_reducer(data.jsgraph());
-      GraphReducer graph_reducer(data.graph(), zone_scope.zone());
+      GraphReducer graph_reducer(data.graph());
       graph_reducer.AddReducer(&vn_reducer);
       graph_reducer.AddReducer(&lowering);
       graph_reducer.AddReducer(&simple_reducer);
@@ -403,14 +402,13 @@ Handle<Code> Pipeline::GenerateCode() {
     {
       // Lower simplified operators and insert changes.
       PhaseScope phase_scope(pipeline_statistics.get(), "simplified lowering");
-      ZonePool::Scope zone_scope(data.zone_pool());
       SourcePositionTable::Scope pos(data.source_positions(),
                                      SourcePosition::Unknown());
       SimplifiedLowering lowering(data.jsgraph());
       lowering.LowerAllNodes();
       ValueNumberingReducer vn_reducer(data.graph_zone());
       SimplifiedOperatorReducer simple_reducer(data.jsgraph());
-      GraphReducer graph_reducer(data.graph(), zone_scope.zone());
+      GraphReducer graph_reducer(data.graph());
       graph_reducer.AddReducer(&vn_reducer);
       graph_reducer.AddReducer(&simple_reducer);
       graph_reducer.ReduceGraph();
@@ -420,7 +418,6 @@ Handle<Code> Pipeline::GenerateCode() {
     {
       // Lower changes that have been inserted before.
       PhaseScope phase_scope(pipeline_statistics.get(), "change lowering");
-      ZonePool::Scope zone_scope(data.zone_pool());
       SourcePositionTable::Scope pos(data.source_positions(),
                                      SourcePosition::Unknown());
       Linkage linkage(data.graph_zone(), info());
@@ -428,7 +425,7 @@ Handle<Code> Pipeline::GenerateCode() {
       SimplifiedOperatorReducer simple_reducer(data.jsgraph());
       ChangeLowering lowering(data.jsgraph(), &linkage);
       MachineOperatorReducer mach_reducer(data.jsgraph());
-      GraphReducer graph_reducer(data.graph(), zone_scope.zone());
+      GraphReducer graph_reducer(data.graph());
       // TODO(titzer): Figure out if we should run all reducers at once here.
       graph_reducer.AddReducer(&vn_reducer);
       graph_reducer.AddReducer(&simple_reducer);
@@ -456,12 +453,11 @@ Handle<Code> Pipeline::GenerateCode() {
   {
     // Lower any remaining generic JSOperators.
     PhaseScope phase_scope(pipeline_statistics.get(), "generic lowering");
-    ZonePool::Scope zone_scope(data.zone_pool());
     SourcePositionTable::Scope pos(data.source_positions(),
                                    SourcePosition::Unknown());
     JSGenericLowering generic(info(), data.jsgraph());
     SelectLowering select(data.jsgraph()->graph(), data.jsgraph()->common());
-    GraphReducer graph_reducer(data.graph(), zone_scope.zone());
+    GraphReducer graph_reducer(data.graph());
     graph_reducer.AddReducer(&generic);
     graph_reducer.AddReducer(&select);
     graph_reducer.ReduceGraph();