[turbofan] Restore basic write barrier elimination.

test/cctest/compiler/test-simplified-lowering.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 <limits>
 
 #include "src/ast/scopes.h"
 #include "src/compiler/access-builder.h"
 #include "src/compiler/change-lowering.h"
 #include "src/compiler/control-builders.h"
@@ skipping 1332 matching lines @@
       Node* store = t.graph()->NewNode(t.simplified()->StoreField(access), t.p0,
                                        val, t.start, t.start);
       t.Effect(store);
       t.LowerAllNodesAndLowerChanges();
       CHECK_EQ(IrOpcode::kStore, store->opcode());
       CHECK_EQ(val, store->InputAt(2));
       CheckFieldAccessArithmetic(access, store);
 
       StoreRepresentation rep = StoreRepresentationOf(store->op());
       if (kMachineReps[i].representation() == MachineRepresentation::kTagged) {
-        CHECK_EQ(kFullWriteBarrier, rep.write_barrier_kind());
+        CHECK_EQ(kNoWriteBarrier, rep.write_barrier_kind());
       }
       CHECK_EQ(kMachineReps[i].representation(), rep.representation());
     }
   }
   {
     HandleAndZoneScope scope;
     Zone* z = scope.main_zone();
     TestingGraph t(Type::Any(), Type::Intersect(Type::SignedSmall(),
                                                 Type::TaggedSigned(), z));
     FieldAccess access = {kTaggedBase, FixedArrayBase::kHeaderSize,
                           Handle<Name>::null(), Type::Any(),
                           MachineType::AnyTagged()};
     Node* store = t.graph()->NewNode(t.simplified()->StoreField(access), t.p0,
                                      t.p1, t.start, t.start);
     t.Effect(store);
     t.LowerAllNodesAndLowerChanges();
     CHECK_EQ(IrOpcode::kStore, store->opcode());
     CHECK_EQ(t.p1, store->InputAt(2));
     StoreRepresentation rep = StoreRepresentationOf(store->op());
-    CHECK_EQ(kFullWriteBarrier, rep.write_barrier_kind());
+    CHECK_EQ(kNoWriteBarrier, rep.write_barrier_kind());
   }
 }
 
 
 TEST(LowerLoadElement_to_load) {
   for (size_t i = 0; i < arraysize(kMachineReps); i++) {
     TestingGraph t(Type::Any(), Type::Signed32());
     ElementAccess access = {kTaggedBase, FixedArrayBase::kHeaderSize,
                             Type::Any(), kMachineReps[i]};
 
@@ skipping 24 matching lines @@
       Node* store = t.graph()->NewNode(t.simplified()->StoreElement(access),
                                        t.p0, t.p1, val, t.start, t.start);
       t.Effect(store);
       t.LowerAllNodesAndLowerChanges();
       CHECK_EQ(IrOpcode::kStore, store->opcode());
       CHECK_EQ(val, store->InputAt(2));
       CheckElementAccessArithmetic(access, store);
 
       StoreRepresentation rep = StoreRepresentationOf(store->op());
       if (kMachineReps[i].representation() == MachineRepresentation::kTagged) {
-        CHECK_EQ(kFullWriteBarrier, rep.write_barrier_kind());
+        CHECK_EQ(kNoWriteBarrier, rep.write_barrier_kind());
       }
       CHECK_EQ(kMachineReps[i].representation(), rep.representation());
     }
   }
   {
     HandleAndZoneScope scope;
     Zone* z = scope.main_zone();
     TestingGraph t(
         Type::Any(), Type::Signed32(),
         Type::Intersect(Type::SignedSmall(), Type::TaggedSigned(), z));
     ElementAccess access = {kTaggedBase, FixedArrayBase::kHeaderSize,
                             Type::Any(), MachineType::AnyTagged()};
     Node* store = t.graph()->NewNode(t.simplified()->StoreElement(access), t.p0,
                                      t.p1, t.p2, t.start, t.start);
     t.Effect(store);
     t.LowerAllNodesAndLowerChanges();
     CHECK_EQ(IrOpcode::kStore, store->opcode());
     CHECK_EQ(t.p2, store->InputAt(2));
     StoreRepresentation rep = StoreRepresentationOf(store->op());
-    CHECK_EQ(kFullWriteBarrier, rep.write_barrier_kind());
+    CHECK_EQ(kNoWriteBarrier, rep.write_barrier_kind());
   }
 }
 
 
 TEST(InsertChangeForLoadElementIndex) {
   // LoadElement(obj: Tagged, index: kTypeInt32 | kRepTagged, length) =>
   //   Load(obj, Int32Add(Int32Mul(ChangeTaggedToInt32(index), #k), #k))
   TestingGraph t(Type::Any(), Type::Signed32());
   ElementAccess access = {kTaggedBase, FixedArrayBase::kHeaderSize, Type::Any(),
                           MachineType::AnyTagged()};
@@ skipping 490 matching lines @@
     t.Return(use);
     t.Lower();
 
     CHECK_EQ(d.expected, PhiRepresentationOf(phi->op()));
   }
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8