Implemented the ctz Turbo Fan operator for x64.

src/compiler/x64/instruction-selector-x64.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 <algorithm>
 
 #include "src/base/adapters.h"
 #include "src/compiler/instruction-selector-impl.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties.h"
@@ skipping 566 matching lines @@
   Emit(kX64Lzcnt, g.DefineAsRegister(node), g.Use(node->InputAt(0)));
 }
 
 
 void InstructionSelector::VisitWord32Clz(Node* node) {
   X64OperandGenerator g(this);
   Emit(kX64Lzcnt32, g.DefineAsRegister(node), g.Use(node->InputAt(0)));
 }
 
 
+void InstructionSelector::VisitWord64Ctz(Node* node) {
+  X64OperandGenerator g(this);
+  Emit(kX64Tzcnt, g.DefineAsRegister(node), g.Use(node->InputAt(0)));
+}
+
+
 void InstructionSelector::VisitWord32Ctz(Node* node) {
   X64OperandGenerator g(this);
   Emit(kX64Tzcnt32, g.DefineAsRegister(node), g.Use(node->InputAt(0)));
 }
 
 
 void InstructionSelector::VisitWord32Popcnt(Node* node) {
   X64OperandGenerator g(this);
   Emit(kX64Popcnt32, g.DefineAsRegister(node), g.Use(node->InputAt(0)));
 }
@@ skipping 1002 matching lines @@
 
 // static
 MachineOperatorBuilder::Flags
 InstructionSelector::SupportedMachineOperatorFlags() {
   MachineOperatorBuilder::Flags flags =
       MachineOperatorBuilder::kFloat32Max |
       MachineOperatorBuilder::kFloat32Min |
       MachineOperatorBuilder::kFloat64Max |
       MachineOperatorBuilder::kFloat64Min |
       MachineOperatorBuilder::kWord32ShiftIsSafe |
-      MachineOperatorBuilder::kWord32Ctz;
+      MachineOperatorBuilder::kWord32Ctz | MachineOperatorBuilder::kWord64Ctz;
   if (CpuFeatures::IsSupported(POPCNT)) {
     flags |= MachineOperatorBuilder::kWord32Popcnt;
   }
   if (CpuFeatures::IsSupported(SSE4_1)) {
     flags |= MachineOperatorBuilder::kFloat64RoundDown |
              MachineOperatorBuilder::kFloat64RoundTruncate;
   }
   return flags;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8