[turbofan] Move global constant optimization to AstGraphBuilder.

src/compiler/js-type-feedback.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/js-type-feedback.h"
 
 #include "src/property-details.h"
 
 #include "src/accessors.h"
 #include "src/ast.h"
@@ skipping 173 matching lines @@
   NodeProperties::MergeControlToEnd(graph(), common(), deopt);
   ReplaceWithValue(node, load, load, check_success);
   return Replace(load);
 }
 
 
 Reduction JSTypeFeedbackSpecializer::ReduceJSLoadGlobal(Node* node) {
   DCHECK(node->opcode() == IrOpcode::kJSLoadGlobal);
   Handle<String> name =
       Handle<String>::cast(LoadGlobalParametersOf(node->op()).name());
-  // Try to optimize loads from the global object.
-  Handle<Object> constant_value =
-      jsgraph()->isolate()->factory()->GlobalConstantFor(name);
-  if (!constant_value.is_null()) {
-    // Always optimize global constants.
-    Node* constant = jsgraph()->Constant(constant_value);
-    ReplaceWithValue(node, constant);
-    return Replace(constant);
-  }
-
   if (global_object_.is_null()) {
     // Nothing else can be done if we don't have a global object.
     return NoChange();
   }
 
   if (mode() == kDeoptimizationEnabled) {
     // Handle lookups in the script context.
     {
       Handle<ScriptContextTable> script_contexts(
           global_object_->native_context()->script_context_table());
@@ skipping 141 matching lines @@
       BailoutId id = OpParameter<FrameStateInfo>(node).bailout_id();
       if (id != BailoutId::None()) return frame_state;
     }
   }
   return nullptr;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8