[arm][arm64] Improve CountTrailingZero implementation.

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 604 matching lines @@
   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::VisitWord32ReverseBits(Node* node) { UNREACHABLE(); }
+
+
+void InstructionSelector::VisitWord64ReverseBits(Node* node) { UNREACHABLE(); }
+
+
 void InstructionSelector::VisitWord32Popcnt(Node* node) {
   X64OperandGenerator g(this);
   Emit(kX64Popcnt32, g.DefineAsRegister(node), g.Use(node->InputAt(0)));
 }
 
 
 void InstructionSelector::VisitWord64Popcnt(Node* node) {
   X64OperandGenerator g(this);
   Emit(kX64Popcnt, g.DefineAsRegister(node), g.Use(node->InputAt(0)));
 }
@@ skipping 1191 matching lines @@
              MachineOperatorBuilder::kFloat64RoundTruncate |
              MachineOperatorBuilder::kFloat32RoundTiesEven |
              MachineOperatorBuilder::kFloat64RoundTiesEven;
   }
   return flags;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8