Revert of [turbofan] Restore basic write barrier elimination.

src/compiler/simplified-lowering.cc

Index: src/compiler/simplified-lowering.cc
diff --git a/src/compiler/simplified-lowering.cc b/src/compiler/simplified-lowering.cc
index af2f2518fa5dddd5fa33f8969bbe4ea0c5b0afed..aceecab39a1710cfa523ef3af6b5e295b5ae84a4 100644
--- a/src/compiler/simplified-lowering.cc
+++ b/src/compiler/simplified-lowering.cc
@@ -6,7 +6,6 @@
 
 #include <limits>
 
-#include "src/address-map.h"
 #include "src/base/bits.h"
 #include "src/code-factory.h"
 #include "src/compiler/access-builder.h"
@@ -19,7 +18,6 @@
 #include "src/compiler/representation-change.h"
 #include "src/compiler/simplified-operator.h"
 #include "src/compiler/source-position.h"
-#include "src/conversions-inl.h"
 #include "src/objects.h"
 #include "src/type-cache.h"
 
@@ -711,71 +709,6 @@
     return changer_->Float64OperatorFor(node->opcode());
   }
 
-  WriteBarrierKind WriteBarrierKindFor(
-      BaseTaggedness base_taggedness,
-      MachineRepresentation field_representation, Type* field_type,
-      Node* value) {
-    if (base_taggedness == kTaggedBase &&
-        field_representation == MachineRepresentation::kTagged) {
-      Type* value_type = NodeProperties::GetType(value);
-      if (field_type->Is(Type::TaggedSigned()) ||
-          value_type->Is(Type::TaggedSigned())) {
-        // Write barriers are only for stores of heap objects.
-        return kNoWriteBarrier;
-      }
-      if (field_type->Is(Type::BooleanOrNullOrUndefined()) ||
-          value_type->Is(Type::BooleanOrNullOrUndefined())) {
-        // Write barriers are not necessary when storing true, false, null or
-        // undefined, because these special oddballs are always in the root set.
-        return kNoWriteBarrier;
-      }
-      if (value_type->IsConstant() &&
-          value_type->AsConstant()->Value()->IsHeapObject()) {
-        Handle<HeapObject> value_object =
-            Handle<HeapObject>::cast(value_type->AsConstant()->Value());
-        if (value_object->IsMap()) {
-          // Write barriers for storing maps are cheaper.
-          return kMapWriteBarrier;
-        }
-        RootIndexMap root_index_map(jsgraph_->isolate());
-        int root_index = root_index_map.Lookup(*value_object);
-        if (root_index != RootIndexMap::kInvalidRootIndex &&
-            jsgraph_->isolate()->heap()->RootIsImmortalImmovable(root_index)) {
-          // Write barriers are unnecessary for immortal immovable roots.
-          return kNoWriteBarrier;
-        }
-      }
-      if (field_type->Is(Type::TaggedPointer()) ||
-          value_type->Is(Type::TaggedPointer())) {
-        // Write barriers for heap objects are cheaper.
-        return kPointerWriteBarrier;
-      }
-      NumberMatcher m(value);
-      if (m.HasValue()) {
-        if (IsSmiDouble(m.Value())) {
-          // Storing a smi doesn't need a write barrier.
-          return kNoWriteBarrier;
-        }
-        // The NumberConstant will be represented as HeapNumber.
-        return kPointerWriteBarrier;
-      }
-      return kFullWriteBarrier;
-    }
-    return kNoWriteBarrier;
-  }
-
-  WriteBarrierKind WriteBarrierKindFor(
-      BaseTaggedness base_taggedness,
-      MachineRepresentation field_representation, int field_offset,
-      Type* field_type, Node* value) {
-    if (base_taggedness == kTaggedBase &&
-        field_offset == HeapObject::kMapOffset) {
-      return kMapWriteBarrier;
-    }
-    return WriteBarrierKindFor(base_taggedness, field_representation,
-                               field_type, value);
-  }
-
   // Dispatching routine for visiting the node {node} with the usage {use}.
   // Depending on the operator, propagate new usage info to the inputs.
   void VisitNode(Node* node, Truncation truncation,
@@ -1203,16 +1136,6 @@
                                   access.machine_type.representation()));
         ProcessRemainingInputs(node, 2);
         SetOutput(node, MachineRepresentation::kNone);
-        if (lower()) {
-          WriteBarrierKind write_barrier_kind = WriteBarrierKindFor(
-              access.base_is_tagged, access.machine_type.representation(),
-              access.offset, access.type, node->InputAt(1));
-          if (write_barrier_kind < access.write_barrier_kind) {
-            access.write_barrier_kind = write_barrier_kind;
-            NodeProperties::ChangeOp(
-                node, jsgraph_->simplified()->StoreField(access));
-          }
-        }
         break;
       }
       case IrOpcode::kLoadBuffer: {
@@ -1278,16 +1201,6 @@
                          access.machine_type.representation()));  // value
         ProcessRemainingInputs(node, 3);
         SetOutput(node, MachineRepresentation::kNone);
-        if (lower()) {
-          WriteBarrierKind write_barrier_kind = WriteBarrierKindFor(
-              access.base_is_tagged, access.machine_type.representation(),
-              access.type, node->InputAt(2));
-          if (write_barrier_kind < access.write_barrier_kind) {
-            access.write_barrier_kind = write_barrier_kind;
-            NodeProperties::ChangeOp(
-                node, jsgraph_->simplified()->StoreElement(access));
-          }
-        }
         break;
       }
       case IrOpcode::kObjectIsCallable: