Introduce simplified BooleanToNumber operator.

src/compiler/simplified-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/simplified-lowering.h"
 
 #include "src/base/bits.h"
 #include "src/code-factory.h"
 #include "src/compiler/common-operator.h"
 #include "src/compiler/graph-inl.h"
@@ skipping 414 matching lines @@
             node->set_op(lowering->machine()->WordEqual());
             node->AppendInput(jsgraph_->zone(), jsgraph_->FalseConstant());
           }
         } else {
           // No input representation requirement; adapt during lowering.
           ProcessInput(node, 0, kTypeBool);
           SetOutput(node, kRepBit);
         }
         break;
       }
+      case IrOpcode::kBooleanToNumber: {
+        if (lower()) {
+          MachineTypeUnion input = GetInfo(node->InputAt(0))->output;
+          if (input & kRepBit) {
+            // BooleanToNumber(x: kRepBit) => x
+            DeferReplacement(node, node->InputAt(0));
+          } else {
+            // BooleanToNumber(x: kRepTagged) => WordEqual(x, #true)
+            node->set_op(lowering->machine()->WordEqual());
+            node->AppendInput(jsgraph_->zone(), jsgraph_->TrueConstant());
+          }
+        } else {
+          // No input representation requirement; adapt during lowering.
+          ProcessInput(node, 0, kTypeBool);
+          SetOutput(node, kMachInt32);
+        }
+        break;
+      }
       case IrOpcode::kNumberEqual:
       case IrOpcode::kNumberLessThan:
       case IrOpcode::kNumberLessThanOrEqual: {
         // Number comparisons reduce to integer comparisons for integer inputs.
         if (BothInputsAre(node, Type::Signed32())) {
           // => signed Int32Cmp
           VisitInt32Cmp(node);
           if (lower()) node->set_op(Int32Op(node));
         } else if (BothInputsAre(node, Type::Unsigned32())) {
           // => unsigned Int32Cmp
@@ skipping 458 matching lines @@
 void SimplifiedLowering::DoStringLessThanOrEqual(Node* node) {
   node->set_op(machine()->IntLessThanOrEqual());
   node->ReplaceInput(0, StringComparison(node, true));
   node->ReplaceInput(1, jsgraph()->SmiConstant(EQUAL));
 }
 
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8