[turbofan] reenable: extend escape analysis to reduce CheckMaps

src/compiler/escape-analysis.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/escape-analysis.h"
 
 #include <limits>
 
 #include "src/base/flags.h"
 #include "src/bootstrapper.h"
@@ skipping 1511 matching lines @@
     ProcessLoadFromPhi(offset, from, node, state);
   } else {
     UpdateReplacement(state, node, nullptr);
   }
 }
 
 void EscapeAnalysis::ProcessCheckMaps(Node* node) {
   DCHECK_EQ(node->opcode(), IrOpcode::kCheckMaps);
   ForwardVirtualState(node);
   Node* checked = ResolveReplacement(NodeProperties::GetValueInput(node, 0));
-  if (FLAG_turbo_experimental) {

[Tobias Tebbi, 2017/04/06 13:45:17]

Why doesn't it ignore whitespace? This CL really just deletes this line...

Alternatively, I could also switch the flag, it is only used here.

-    VirtualState* state = virtual_states_[node->id()];
-    if (VirtualObject* object = GetVirtualObject(state, checked)) {
-      if (!object->IsTracked()) {
-        if (status_analysis_->SetEscaped(node)) {
-          TRACE(
-              "Setting #%d (%s) to escaped because checked object #%i is not "
-              "tracked\n",
-              node->id(), node->op()->mnemonic(), object->id());
-        }
+  VirtualState* state = virtual_states_[node->id()];
+  if (VirtualObject* object = GetVirtualObject(state, checked)) {
+    if (!object->IsTracked()) {
+      if (status_analysis_->SetEscaped(node)) {
+        TRACE(
+            "Setting #%d (%s) to escaped because checked object #%i is not "
+            "tracked\n",
+            node->id(), node->op()->mnemonic(), object->id());
+      }
+      return;
+    }
+    CheckMapsParameters params = CheckMapsParametersOf(node->op());
+
+    Node* value = object->GetField(HeapObject::kMapOffset / kPointerSize);
+    if (value) {
+      value = ResolveReplacement(value);
+      // TODO(tebbi): We want to extend this beyond constant folding with a
+      // CheckMapsValue operator that takes the load-eliminated map value as
+      // input.
+      if (value->opcode() == IrOpcode::kHeapConstant &&
+          params.maps().contains(ZoneHandleSet<Map>(
+              Handle<Map>::cast(OpParameter<Handle<HeapObject>>(value))))) {
+        TRACE("CheckMaps #%i seems to be redundant (until now).\n", node->id());
         return;
       }
-      CheckMapsParameters params = CheckMapsParametersOf(node->op());
-
-      Node* value = object->GetField(HeapObject::kMapOffset / kPointerSize);
-      if (value) {
-        value = ResolveReplacement(value);
-        // TODO(tebbi): We want to extend this beyond constant folding with a
-        // CheckMapsValue operator that takes the load-eliminated map value as
-        // input.
-        if (value->opcode() == IrOpcode::kHeapConstant &&
-            params.maps().contains(ZoneHandleSet<Map>(
-                Handle<Map>::cast(OpParameter<Handle<HeapObject>>(value))))) {
-          TRACE("CheckMaps #%i seems to be redundant (until now).\n",
-                node->id());
-          return;
-        }
-      }
     }
   }
   if (status_analysis_->SetEscaped(node)) {
     TRACE("Setting #%d (%s) to escaped (checking #%i)\n", node->id(),
           node->op()->mnemonic(), checked->id());
   }
 }
 
 void EscapeAnalysis::ProcessLoadElement(Node* node) {
   DCHECK_EQ(node->opcode(), IrOpcode::kLoadElement);
@@ skipping 229 matching lines @@
     }
   }
   return false;
 }
 
 Graph* EscapeAnalysis::graph() const { return status_analysis_->graph(); }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8