[x64] Recognize zero extension of 8-bit and 16-bit values.

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/compiler/instruction-selector-impl.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties.h"
 
@@ skipping 348 matching lines @@
 
 // Shared routine for multiple binary operations.
 static void VisitBinop(InstructionSelector* selector, Node* node,
                        InstructionCode opcode) {
   FlagsContinuation cont;
   VisitBinop(selector, node, opcode, &cont);
 }
 
 
 void InstructionSelector::VisitWord32And(Node* node) {
-  VisitBinop(this, node, kX64And32);
+  X64OperandGenerator g(this);
+  Uint32BinopMatcher m(node);
+  if (m.right().Is(0xff)) {
+    Emit(kX64Movzxbl, g.DefineAsRegister(node), g.Use(m.left().node()));
+  } else if (m.right().Is(0xffff)) {
+    Emit(kX64Movzxwl, g.DefineAsRegister(node), g.Use(m.left().node()));
+  } else {
+    VisitBinop(this, node, kX64And32);
+  }
 }
 
 
 void InstructionSelector::VisitWord64And(Node* node) {
   VisitBinop(this, node, kX64And);
 }
 
 
 void InstructionSelector::VisitWord32Or(Node* node) {
   VisitBinop(this, node, kX64Or32);
@@ skipping 997 matching lines @@
            MachineOperatorBuilder::kFloat64Ceil |
            MachineOperatorBuilder::kFloat64RoundTruncate |
            MachineOperatorBuilder::kWord32ShiftIsSafe;
   }
   return MachineOperatorBuilder::kNoFlags;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8