Merge (x & y) == 0 pattern to emit a single test instruction.

runtime/vm/assembler_x64.h

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_ASSEMBLER_X64_H_
 #define VM_ASSEMBLER_X64_H_
 
 #ifndef VM_ASSEMBLER_H_
 #error Do not include assembler_x64.h directly; use assembler.h instead.
 #endif
@@ skipping 482 matching lines @@
 
   void CompareImmediate(Register reg, const Immediate& imm, Register pp);
   void CompareImmediate(const Address& address, const Immediate& imm,
                         Register pp);
 
   void testl(Register reg1, Register reg2);
   void testl(Register reg, const Immediate& imm);
 
   void testq(Register reg1, Register reg2);
   void testq(Register reg, const Immediate& imm);
+  void TestImmediate(Register dst, const Immediate& imm, Register pp);
 
   void andl(Register dst, Register src);
   void andl(Register dst, const Immediate& imm);
 
   void orl(Register dst, Register src);
   void orl(Register dst, const Immediate& imm);
 
   void xorl(Register dst, Register src);
 
   void andq(Register dst, Register src);
@@ skipping 535 matching lines @@
 }
 
 
 inline void Assembler::EmitOperandSizeOverride() {
   EmitUint8(0x66);
 }
 
 }  // namespace dart
 
 #endif  // VM_ASSEMBLER_X64_H_