[turbofan] Improve AstGraphBuilder::BuildToBoolean() for heap constants.

src/compiler/ast-graph-builder.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/ast-graph-builder.h"
 
 #include "src/compiler.h"
 #include "src/compiler/ast-loop-assignment-analyzer.h"
 #include "src/compiler/control-builders.h"
 #include "src/compiler/machine-operator.h"
@@ skipping 2108 matching lines @@
   // TODO(titzer): this should be in a JSOperatorReducer.
   switch (input->opcode()) {
     case IrOpcode::kInt32Constant:
       return jsgraph_->BooleanConstant(!Int32Matcher(input).Is(0));
     case IrOpcode::kFloat64Constant:
       return jsgraph_->BooleanConstant(!Float64Matcher(input).Is(0));
     case IrOpcode::kNumberConstant:
       return jsgraph_->BooleanConstant(!NumberMatcher(input).Is(0));
     case IrOpcode::kHeapConstant: {
       Handle<Object> object = HeapObjectMatcher<Object>(input).Value().handle();
-      if (object->IsTrue()) return jsgraph_->TrueConstant();
-      if (object->IsFalse()) return jsgraph_->FalseConstant();
-      // TODO(turbofan): other constants.
-      break;
+      return jsgraph_->BooleanConstant(object->BooleanValue());
     }
     default:
       break;
   }
   if (NodeProperties::IsTyped(input)) {
     Type* upper = NodeProperties::GetBounds(input).upper;
     if (upper->Is(Type::Boolean())) return input;
   }
 
   return NewNode(javascript()->ToBoolean(), input);
@@ skipping 102 matching lines @@
 
 BitVector* AstGraphBuilder::GetVariablesAssignedInLoop(
     IterationStatement* stmt) {
   if (loop_assignment_analysis_ == NULL) return NULL;
   return loop_assignment_analysis_->GetVariablesAssignedInLoop(stmt);
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8