Revert remove dead hole check logic

src/crankshaft/s390/lithium-codegen-s390.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/crankshaft/s390/lithium-codegen-s390.h"
 
 #include "src/base/bits.h"
 #include "src/builtins/builtins-constructor.h"
 #include "src/code-factory.h"
@@ skipping 2616 matching lines @@
     __ AddP(sp, sp, r0);
   }
 
   __ Ret();
 }
 
 void LCodeGen::DoLoadContextSlot(LLoadContextSlot* instr) {
   Register context = ToRegister(instr->context());
   Register result = ToRegister(instr->result());
   __ LoadP(result, ContextMemOperand(context, instr->slot_index()));
+  if (instr->hydrogen()->RequiresHoleCheck()) {
+    __ CompareRoot(result, Heap::kTheHoleValueRootIndex);
+    if (instr->hydrogen()->DeoptimizesOnHole()) {
+      DeoptimizeIf(eq, instr, DeoptimizeReason::kHole);
+    } else {
+      Label skip;
+      __ bne(&skip, Label::kNear);
+      __ mov(result, Operand(factory()->undefined_value()));
+      __ bind(&skip);
+    }
+  }
 }
 
 void LCodeGen::DoStoreContextSlot(LStoreContextSlot* instr) {
   Register context = ToRegister(instr->context());
   Register value = ToRegister(instr->value());
   Register scratch = scratch0();
   MemOperand target = ContextMemOperand(context, instr->slot_index());
 
+  Label skip_assignment;
+
+  if (instr->hydrogen()->RequiresHoleCheck()) {
+    __ LoadP(scratch, target);
+    __ CompareRoot(scratch, Heap::kTheHoleValueRootIndex);
+    if (instr->hydrogen()->DeoptimizesOnHole()) {
+      DeoptimizeIf(eq, instr, DeoptimizeReason::kHole);
+    } else {
+      __ bne(&skip_assignment);
+    }
+  }
+
   __ StoreP(value, target);
   if (instr->hydrogen()->NeedsWriteBarrier()) {
     SmiCheck check_needed = instr->hydrogen()->value()->type().IsHeapObject()
                                 ? OMIT_SMI_CHECK
                                 : INLINE_SMI_CHECK;
     __ RecordWriteContextSlot(context, target.offset(), value, scratch,
                               GetLinkRegisterState(), kSaveFPRegs,
                               EMIT_REMEMBERED_SET, check_needed);
   }
+
+  __ bind(&skip_assignment);
 }
 
 void LCodeGen::DoLoadNamedField(LLoadNamedField* instr) {
   HObjectAccess access = instr->hydrogen()->access();
   int offset = access.offset();
   Register object = ToRegister(instr->object());
 
   if (access.IsExternalMemory()) {
     Register result = ToRegister(instr->result());
     MemOperand operand = MemOperand(object, offset);
@@ skipping 2889 matching lines @@
   __ LoadP(result,
            FieldMemOperand(scratch, FixedArray::kHeaderSize - kPointerSize));
   __ bind(deferred->exit());
   __ bind(&done);
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8