[arm][arm64] Improve CountTrailingZero implementation.

src/compiler/arm64/instruction-selector-arm64.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/instruction-selector-impl.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties.h"
 
 namespace v8 {
 namespace internal {
@@ skipping 956 matching lines @@
   Emit(kArm64Clz32, g.DefineAsRegister(node), g.UseRegister(node->InputAt(0)));
 }
 
 
 void InstructionSelector::VisitWord32Ctz(Node* node) { UNREACHABLE(); }
 
 
 void InstructionSelector::VisitWord64Ctz(Node* node) { UNREACHABLE(); }
 
 
+void InstructionSelector::VisitWord32ReverseBits(Node* node) {
+  VisitRR(this, kArm64Rbit32, node);
+}
+
+
+void InstructionSelector::VisitWord64ReverseBits(Node* node) {
+  VisitRR(this, kArm64Rbit, node);
+}
+
+
 void InstructionSelector::VisitWord32Popcnt(Node* node) { UNREACHABLE(); }
 
 
 void InstructionSelector::VisitWord64Popcnt(Node* node) { UNREACHABLE(); }
 
 
 void InstructionSelector::VisitInt32Add(Node* node) {
   Arm64OperandGenerator g(this);
   Int32BinopMatcher m(node);
   // Select Madd(x, y, z) for Add(Mul(x, y), z).
@@ skipping 1225 matching lines @@
          MachineOperatorBuilder::kFloat64RoundDown |
          MachineOperatorBuilder::kFloat32RoundUp |
          MachineOperatorBuilder::kFloat64RoundUp |
          MachineOperatorBuilder::kFloat32RoundTruncate |
          MachineOperatorBuilder::kFloat64RoundTruncate |
          MachineOperatorBuilder::kFloat64RoundTiesAway |
          MachineOperatorBuilder::kFloat32RoundTiesEven |
          MachineOperatorBuilder::kFloat64RoundTiesEven |
          MachineOperatorBuilder::kWord32ShiftIsSafe |
          MachineOperatorBuilder::kInt32DivIsSafe |
-         MachineOperatorBuilder::kUint32DivIsSafe;
+         MachineOperatorBuilder::kUint32DivIsSafe |
+         MachineOperatorBuilder::kWord32ReverseBits |
+         MachineOperatorBuilder::kWord64ReverseBits;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8