Revert of [Atomics] Remove Atomics code stubs; use TF ops

src/compiler/arm/instruction-selector-arm.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/base/adapters.h"
 #include "src/base/bits.h"
 #include "src/compiler/instruction-selector-impl.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties.h"
 
@@ skipping 1796 matching lines @@
       CanCover(node, left)) {
     left = left->InputAt(1);
     Emit(kArmVmovF64U32U32, g.DefineAsRegister(node), g.UseRegister(left),
          g.UseRegister(right));
     return;
   }
   Emit(kArmVmovHighF64U32, g.DefineSameAsFirst(node), g.UseRegister(left),
        g.UseRegister(right));
 }
 
-void InstructionSelector::VisitAtomicLoad(Node* node) {
-  LoadRepresentation load_rep = LoadRepresentationOf(node->op());
-  ArmOperandGenerator g(this);
-  Node* base = node->InputAt(0);
-  Node* index = node->InputAt(1);
-  ArchOpcode opcode = kArchNop;
-  switch (load_rep.representation()) {
-    case MachineRepresentation::kWord8:
-      opcode = load_rep.IsSigned() ? kAtomicLoadInt8 : kAtomicLoadUint8;
-      break;
-    case MachineRepresentation::kWord16:
-      opcode = load_rep.IsSigned() ? kAtomicLoadInt16 : kAtomicLoadUint16;
-      break;
-    case MachineRepresentation::kWord32:
-      opcode = kAtomicLoadWord32;
-      break;
-    default:
-      UNREACHABLE();
-      return;
-  }
-  Emit(opcode | AddressingModeField::encode(kMode_Offset_RR),
-       g.DefineAsRegister(node), g.UseRegister(base), g.UseRegister(index));
-}
 
 // static
 MachineOperatorBuilder::Flags
 InstructionSelector::SupportedMachineOperatorFlags() {
   MachineOperatorBuilder::Flags flags =
       MachineOperatorBuilder::kInt32DivIsSafe |
       MachineOperatorBuilder::kUint32DivIsSafe;
   if (CpuFeatures::IsSupported(ARMv7)) {
     flags |= MachineOperatorBuilder::kWord32ReverseBits;
   }
@@ skipping 11 matching lines @@
              MachineOperatorBuilder::kFloat32Max |
              MachineOperatorBuilder::kFloat64Min |
              MachineOperatorBuilder::kFloat64Max;
   }
   return flags;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8