[crankshaft] Remove dead Variable hole-checking code

src/crankshaft/mips64/lithium-mips64.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/mips64/lithium-mips64.h"
 
 #include <sstream>
 
 #if V8_TARGET_ARCH_MIPS64
 
@@ skipping 1907 matching lines @@
     return DefineAsRegister(new(zone()) LConstantT);
   } else {
     UNREACHABLE();
     return NULL;
   }
 }
 
 
 LInstruction* LChunkBuilder::DoLoadContextSlot(HLoadContextSlot* instr) {
   LOperand* context = UseRegisterAtStart(instr->value());
-  LInstruction* result =
-      DefineAsRegister(new(zone()) LLoadContextSlot(context));
-  if (instr->RequiresHoleCheck() && instr->DeoptimizesOnHole()) {
-    result = AssignEnvironment(result);
-  }
-  return result;
+  return DefineAsRegister(new (zone()) LLoadContextSlot(context));
 }
 
 
 LInstruction* LChunkBuilder::DoStoreContextSlot(HStoreContextSlot* instr) {
   LOperand* context;
   LOperand* value;
   if (instr->NeedsWriteBarrier()) {
     context = UseTempRegister(instr->context());
     value = UseTempRegister(instr->value());
   } else {
     context = UseRegister(instr->context());
     value = UseRegister(instr->value());
   }
-  LInstruction* result = new(zone()) LStoreContextSlot(context, value);
-  if (instr->RequiresHoleCheck() && instr->DeoptimizesOnHole()) {
-    result = AssignEnvironment(result);
-  }
-  return result;
+  return new (zone()) LStoreContextSlot(context, value);
 }
 
 
 LInstruction* LChunkBuilder::DoLoadNamedField(HLoadNamedField* instr) {
   LOperand* obj = UseRegisterAtStart(instr->object());
   return DefineAsRegister(new(zone()) LLoadNamedField(obj));
 }
 
 
 LInstruction* LChunkBuilder::DoLoadFunctionPrototype(
@@ skipping 383 matching lines @@
   LOperand* index = UseTempRegister(instr->index());
   LLoadFieldByIndex* load = new(zone()) LLoadFieldByIndex(object, index);
   LInstruction* result = DefineSameAsFirst(load);
   return AssignPointerMap(result);
 }
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_MIPS64