MIPS: [Atomics] Remove Atomics code stubs; use TF ops.

src/compiler/mips64/instruction-selector-mips64.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 1965 matching lines @@
     case MachineRepresentation::kWord16:
       opcode = load_rep.IsSigned() ? kAtomicLoadInt16 : kAtomicLoadUint16;
       break;
     case MachineRepresentation::kWord32:
       opcode = kAtomicLoadWord32;
       break;
     default:
       UNREACHABLE();
       return;
   }
-  Emit(opcode | AddressingModeField::encode(kMode_MRI),
-       g.DefineAsRegister(node), g.UseRegister(base), g.UseRegister(index));
+  if (g.CanBeImmediate(index, opcode)) {
+    Emit(opcode | AddressingModeField::encode(kMode_MRI),
+         g.DefineAsRegister(node), g.UseRegister(base), g.UseImmediate(index));
+  } else {
+    InstructionOperand addr_reg = g.TempRegister();
+    Emit(kMips64Dadd | AddressingModeField::encode(kMode_None), addr_reg,
+         g.UseRegister(index), g.UseRegister(base));
+    // Emit desired load opcode, using temp addr_reg.
+    Emit(opcode | AddressingModeField::encode(kMode_MRI),
+         g.DefineAsRegister(node), addr_reg, g.TempImmediate(0));
+  }
 }
 
 // static
 MachineOperatorBuilder::Flags
 InstructionSelector::SupportedMachineOperatorFlags() {
   return MachineOperatorBuilder::kWord32Ctz |
          MachineOperatorBuilder::kWord64Ctz |
          MachineOperatorBuilder::kWord32Popcnt |
          MachineOperatorBuilder::kWord64Popcnt |
          MachineOperatorBuilder::kWord32ShiftIsSafe |
          MachineOperatorBuilder::kInt32DivIsSafe |
          MachineOperatorBuilder::kUint32DivIsSafe |
          MachineOperatorBuilder::kFloat64Min |
          MachineOperatorBuilder::kFloat64Max |
          MachineOperatorBuilder::kFloat32Min |
          MachineOperatorBuilder::kFloat32Max |
          MachineOperatorBuilder::kFloat64RoundDown |
          MachineOperatorBuilder::kFloat32RoundDown |
          MachineOperatorBuilder::kFloat64RoundUp |
          MachineOperatorBuilder::kFloat32RoundUp |
          MachineOperatorBuilder::kFloat64RoundTruncate |
          MachineOperatorBuilder::kFloat32RoundTruncate |
          MachineOperatorBuilder::kFloat64RoundTiesEven |
          MachineOperatorBuilder::kFloat32RoundTiesEven;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8