[turbofan] Optimize loads of global constants in JSTypedLowering.

src/compiler/js-typed-lowering.cc

 // Copyright 2014 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/access-builder.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/js-typed-lowering.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties.h"
 #include "src/compiler/operator-properties.h"
@@ skipping 729 matching lines @@
   Node* const input = node->InputAt(0);
   Reduction reduction = ReduceJSToStringInput(input);
   if (reduction.Changed()) {
     NodeProperties::ReplaceWithValue(node, reduction.replacement());
     return reduction;
   }
   return NoChange();
 }
 
 
+static bool IsGlobalObject(Node* node) {
+  return NodeProperties::IsTyped(node) &&
+         NodeProperties::GetBounds(node).upper->Is(Type::GlobalObject());
+}
+
+
+Reduction JSTypedLowering::ReduceJSLoadNamed(Node* node) {
+  if (IsGlobalObject(node->InputAt(0))) {
+    // Optimize global constants like "undefined", "Infinity", and "NaN".
+    Handle<Name> name = LoadNamedParametersOf(node->op()).name().handle();
+    Handle<Object> constant_value = factory()->GlobalConstantFor(name);
+    if (!constant_value.is_null()) {
+      Node* constant = jsgraph()->Constant(constant_value);
+      NodeProperties::ReplaceWithValue(node, constant);
+      return Replace(constant);
+    }
+  }
+  return NoChange();
+}
+
+
 Reduction JSTypedLowering::ReduceJSLoadProperty(Node* node) {
   Node* key = NodeProperties::GetValueInput(node, 1);
   Node* base = NodeProperties::GetValueInput(node, 0);
   Type* key_type = NodeProperties::GetBounds(key).upper;
   // TODO(mstarzinger): This lowering is not correct if:
   //   a) The typed array or it's buffer is neutered.
   HeapObjectMatcher<Object> mbase(base);
   if (mbase.HasValue() && mbase.Value().handle()->IsJSTypedArray()) {
     Handle<JSTypedArray> const array =
         Handle<JSTypedArray>::cast(mbase.Value().handle());
@@ skipping 229 matching lines @@
     case IrOpcode::kJSModulus:
       return ReduceNumberBinop(node, simplified()->NumberModulus());
     case IrOpcode::kJSUnaryNot:
       return ReduceJSUnaryNot(node);
     case IrOpcode::kJSToBoolean:
       return ReduceJSToBoolean(node);
     case IrOpcode::kJSToNumber:
       return ReduceJSToNumber(node);
     case IrOpcode::kJSToString:
       return ReduceJSToString(node);
+    case IrOpcode::kJSLoadNamed:
+      return ReduceJSLoadNamed(node);
     case IrOpcode::kJSLoadProperty:
       return ReduceJSLoadProperty(node);
     case IrOpcode::kJSStoreProperty:
       return ReduceJSStoreProperty(node);
     case IrOpcode::kJSLoadContext:
       return ReduceJSLoadContext(node);
     case IrOpcode::kJSStoreContext:
       return ReduceJSStoreContext(node);
     default:
       break;
@@ skipping 68 matching lines @@
 }
 
 
 MachineOperatorBuilder* JSTypedLowering::machine() const {
   return jsgraph()->machine();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8