Add support for enabling DCHECKs in release mode

src/compiler/register-allocator.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/linkage.h"
 #include "src/compiler/register-allocator.h"
 #include "src/string-stream.h"
 
 namespace v8 {
 namespace internal {
@@ skipping 1823 matching lines @@
         AddToInactive(current);
       }
     }
   }
 
   while (!unhandled_live_ranges_.is_empty()) {
     DCHECK(UnhandledIsSorted());
     LiveRange* current = unhandled_live_ranges_.RemoveLast();
     DCHECK(UnhandledIsSorted());
     LifetimePosition position = current->Start();
-#ifdef DEBUG
+#if DCHECK_IS_ON
     allocation_finger_ = position;
 #endif
     TraceAlloc("Processing interval %d start=%d\n", current->id(),
                position.Value());
 
     if (current->HasAllocatedSpillOperand()) {
       TraceAlloc("Live range %d already has a spill operand\n", current->id());
       LifetimePosition next_pos = position;
       if (code()->IsGapAt(next_pos.InstructionIndex())) {
         next_pos = next_pos.NextInstruction();
@@ skipping 624 matching lines @@
   } else {
     DCHECK(range->Kind() == GENERAL_REGISTERS);
     assigned_registers_->Add(reg);
   }
   range->set_assigned_register(reg, code_zone());
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8