Revert of [compiler] Drop the CompareNilIC.

src/crankshaft/hydrogen-instructions.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/crankshaft/hydrogen-instructions.h"
 
 #include "src/base/bits.h"
 #include "src/base/safe_math.h"
 #include "src/crankshaft/hydrogen-infer-representation.h"
 #include "src/double.h"
@@ skipping 3254 matching lines @@
   return false;
 }
 
 
 bool HIsUndetectableAndBranch::KnownSuccessorBlock(HBasicBlock** block) {
   if (FLAG_fold_constants && value()->IsConstant()) {
     *block = HConstant::cast(value())->IsUndetectable()
         ? FirstSuccessor() : SecondSuccessor();
     return true;
   }
-  if (value()->type().IsNull() || value()->type().IsUndefined()) {
-    *block = FirstSuccessor();
-    return true;
-  }
-  if (value()->type().IsBoolean() ||
-      value()->type().IsSmi() ||
-      value()->type().IsString() ||
-      value()->type().IsJSReceiver()) {
-    *block = SecondSuccessor();
-    return true;
-  }
   *block = NULL;
   return false;
 }
 
 
 bool HHasInstanceTypeAndBranch::KnownSuccessorBlock(HBasicBlock** block) {
   if (FLAG_fold_constants && value()->IsConstant()) {
     InstanceType type = HConstant::cast(value())->GetInstanceType();
     *block = (from_ <= type) && (type <= to_)
         ? FirstSuccessor() : SecondSuccessor();
@@ skipping 1358 matching lines @@
     case HObjectAccess::kExternalMemory:
       os << "[external-memory]";
       break;
   }
 
   return os << "@" << access.offset();
 }
 
 }  // namespace internal
 }  // namespace v8