Add support for enabling DCHECKs in release mode

src/x64/macro-assembler-x64.cc

 // Copyright 2012 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/v8.h"
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/base/bits.h"
 #include "src/base/division-by-constant.h"
@@ skipping 5036 matching lines @@
 
   call(function);
   DCHECK(base::OS::ActivationFrameAlignment() != 0);
   DCHECK(num_arguments >= 0);
   int argument_slots_on_stack =
       ArgumentStackSlotsForCFunctionCall(num_arguments);
   movp(rsp, Operand(rsp, argument_slots_on_stack * kRegisterSize));
 }
 
 
-#ifdef DEBUG
+#if DCHECK_IS_ON
 bool AreAliased(Register reg1,
                 Register reg2,
                 Register reg3,
                 Register reg4,
                 Register reg5,
                 Register reg6,
                 Register reg7,
                 Register reg8) {
   int n_of_valid_regs = reg1.is_valid() + reg2.is_valid() +
       reg3.is_valid() + reg4.is_valid() + reg5.is_valid() + reg6.is_valid() +
@@ skipping 341 matching lines @@
   if (mag.shift > 0) sarl(rdx, Immediate(mag.shift));
   movl(rax, dividend);
   shrl(rax, Immediate(31));
   addl(rdx, rax);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64