text: // Copyright 2013 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/v8.h"
  
  #if V8_TARGET_ARCH_X64
  
  #include "src/base/bits.h"
  #include "src/code-factory.h"
  #include "src/code-stubs.h"
  #include "src/cpu-profiler.h"
  #include "src/hydrogen-osr.h"
  #include "src/ic/ic.h"
  #include "src/ic/stub-cache.h"
  #include "src/x64/lithium-codegen-x64.h"
  
  namespace v8 {
  namespace internal {
  
  
  // When invoking builtins, we need to record the safepoint in the middle of
  // the invoke instruction sequence generated by the macro assembler.
  class SafepointGenerator final : public CallWrapper {
   public:
    SafepointGenerator(LCodeGen* codegen,
                       LPointerMap* pointers,
                       Safepoint::DeoptMode mode)
        : codegen_(codegen),
          pointers_(pointers),
          deopt_mode_(mode) { }
    virtual ~SafepointGenerator() {}
  
    void BeforeCall(int call_size) const override {}
  
    void AfterCall() const override {
      codegen_->RecordSafepoint(pointers_, deopt_mode_);
    }
  
   private:
    LCodeGen* codegen_;
    LPointerMap* pointers_;
    Safepoint::DeoptMode deopt_mode_;
  };
  
  
  #define __ masm()->
  
  bool LCodeGen::GenerateCode() {
    LPhase phase("Z_Code generation", chunk());
    DCHECK(is_unused());
    status_ = GENERATING;
  
    // Open a frame scope to indicate that there is a frame on the stack.  The
    // MANUAL indicates that the scope shouldn't actually generate code to set up
    // the frame (that is done in GeneratePrologue).
    FrameScope frame_scope(masm_, StackFrame::MANUAL);
  
    return GeneratePrologue() &&
        GenerateBody() &&
        GenerateDeferredCode() &&
        GenerateJumpTable() &&
        GenerateSafepointTable();
  }
  
  
  void LCodeGen::FinishCode(Handle<Code> code) {
    DCHECK(is_done());
    code->set_stack_slots(GetStackSlotCount());
    code->set_safepoint_table_offset(safepoints_.GetCodeOffset());
    PopulateDeoptimizationData(code);
  }
  
  
  #ifdef _MSC_VER
  void LCodeGen::MakeSureStackPagesMapped(int offset) {
    const int kPageSize = 4 * KB;
    for (offset -= kPageSize; offset > 0; offset -= kPageSize) {
      __ movp(Operand(rsp, offset), rax);
    }
  }
  #endif
  
  
  void LCodeGen::SaveCallerDoubles() {
    DCHECK(info()->saves_caller_doubles());
    DCHECK(NeedsEagerFrame());
    Comment(";;; Save clobbered callee double registers");
    int count = 0;
    BitVector* doubles = chunk()->allocated_double_registers();
    BitVector::Iterator save_iterator(doubles);
    while (!save_iterator.Done()) {
      __ movsd(MemOperand(rsp, count * kDoubleSize),
               XMMRegister::FromAllocationIndex(save_iterator.Current()));
      save_iterator.Advance();
      count++;
    }
  }
  
  
  void LCodeGen::RestoreCallerDoubles() {
    DCHECK(info()->saves_caller_doubles());
    DCHECK(NeedsEagerFrame());
    Comment(";;; Restore clobbered callee double registers");
    BitVector* doubles = chunk()->allocated_double_registers();
    BitVector::Iterator save_iterator(doubles);
    int count = 0;
    while (!save_iterator.Done()) {
      __ movsd(XMMRegister::FromAllocationIndex(save_iterator.Current()),
               MemOperand(rsp, count * kDoubleSize));
      save_iterator.Advance();
      count++;
    }
  }
  
  
  bool LCodeGen::GeneratePrologue() {
    DCHECK(is_generating());
  
    if (info()->IsOptimizing()) {
      ProfileEntryHookStub::MaybeCallEntryHook(masm_);
  
  #ifdef DEBUG
      if (strlen(FLAG_stop_at) > 0 &&
          info_->function()->name()->IsUtf8EqualTo(CStrVector(FLAG_stop_at))) {
        __ int3();
      }
  #endif
  
      // Sloppy mode functions need to replace the receiver with the global proxy
      // when called as functions (without an explicit receiver object).
      if (is_sloppy(info_->language_mode()) && info()->MayUseThis() &&
          !info_->is_native()) {
        Label ok;
        StackArgumentsAccessor args(rsp, scope()->num_parameters());
        __ movp(rcx, args.GetReceiverOperand());
  
        __ CompareRoot(rcx, Heap::kUndefinedValueRootIndex);
        __ j(not_equal, &ok, Label::kNear);
  
        __ movp(rcx, GlobalObjectOperand());
        __ movp(rcx, FieldOperand(rcx, GlobalObject::kGlobalProxyOffset));
  
        __ movp(args.GetReceiverOperand(), rcx);
  
        __ bind(&ok);
      }
    }
  
    info()->set_prologue_offset(masm_->pc_offset());
    if (NeedsEagerFrame()) {
      DCHECK(!frame_is_built_);
      frame_is_built_ = true;
      if (info()->IsStub()) {
        __ StubPrologue();
      } else {
        __ Prologue(info()->IsCodePreAgingActive());
      }
      info()->AddNoFrameRange(0, masm_->pc_offset());
    }
  
    // Reserve space for the stack slots needed by the code.
    int slots = GetStackSlotCount();
    if (slots > 0) {
      if (FLAG_debug_code) {
        __ subp(rsp, Immediate(slots * kPointerSize));
  #ifdef _MSC_VER
        MakeSureStackPagesMapped(slots * kPointerSize);
  #endif
        __ Push(rax);
        __ Set(rax, slots);
        __ Set(kScratchRegister, kSlotsZapValue);
        Label loop;
        __ bind(&loop);
        __ movp(MemOperand(rsp, rax, times_pointer_size, 0),
                kScratchRegister);
        __ decl(rax);
        __ j(not_zero, &loop);
        __ Pop(rax);
      } else {
        __ subp(rsp, Immediate(slots * kPointerSize));
  #ifdef _MSC_VER
        MakeSureStackPagesMapped(slots * kPointerSize);
  #endif
      }
  
      if (info()->saves_caller_doubles()) {
        SaveCallerDoubles();
      }
    }
  
    // Possibly allocate a local context.
    int heap_slots = info_->num_heap_slots() - Context::MIN_CONTEXT_SLOTS;
    if (heap_slots > 0) {
      Comment(";;; Allocate local context");
      bool need_write_barrier = true;
      // Argument to NewContext is the function, which is still in rdi.
      DCHECK(!info()->scope()->is_script_scope());
      if (heap_slots <= FastNewContextStub::kMaximumSlots) {
        FastNewContextStub stub(isolate(), heap_slots);
        __ CallStub(&stub);
        // Result of FastNewContextStub is always in new space.
        need_write_barrier = false;
      } else {
        __ Push(rdi);
        __ CallRuntime(Runtime::kNewFunctionContext, 1);
      }
      RecordSafepoint(Safepoint::kNoLazyDeopt);
      // Context is returned in rax.  It replaces the context passed to us.
      // It's saved in the stack and kept live in rsi.
      __ movp(rsi, rax);
      __ movp(Operand(rbp, StandardFrameConstants::kContextOffset), rax);
  
      // Copy any necessary parameters into the context.
      int num_parameters = scope()->num_parameters();
      for (int i = 0; i < num_parameters; i++) {
        Variable* var = scope()->parameter(i);
        if (var->IsContextSlot()) {
          int parameter_offset = StandardFrameConstants::kCallerSPOffset +
              (num_parameters - 1 - i) * kPointerSize;
          // Load parameter from stack.
          __ movp(rax, Operand(rbp, parameter_offset));
          // Store it in the context.
          int context_offset = Context::SlotOffset(var->index());
          __ movp(Operand(rsi, context_offset), rax);
          // Update the write barrier. This clobbers rax and rbx.
          if (need_write_barrier) {
            __ RecordWriteContextSlot(rsi, context_offset, rax, rbx, kSaveFPRegs);
          } else if (FLAG_debug_code) {
            Label done;
            __ JumpIfInNewSpace(rsi, rax, &done, Label::kNear);
            __ Abort(kExpectedNewSpaceObject);
            __ bind(&done);
          }
        }
      }
      Comment(";;; End allocate local context");
    }
  
    // Trace the call.
    if (FLAG_trace && info()->IsOptimizing()) {
      __ CallRuntime(Runtime::kTraceEnter, 0);
    }
    return !is_aborted();
  }
  
  
  void LCodeGen::GenerateOsrPrologue() {
    // Generate the OSR entry prologue at the first unknown OSR value, or if there
    // are none, at the OSR entrypoint instruction.
    if (osr_pc_offset_ >= 0) return;
  
    osr_pc_offset_ = masm()->pc_offset();
  
    // Adjust the frame size, subsuming the unoptimized frame into the
    // optimized frame.
    int slots = GetStackSlotCount() - graph()->osr()->UnoptimizedFrameSlots();
    DCHECK(slots >= 0);
    __ subp(rsp, Immediate(slots * kPointerSize));
  }
  
  
  void LCodeGen::GenerateBodyInstructionPre(LInstruction* instr) {
    if (instr->IsCall()) {
      EnsureSpaceForLazyDeopt(Deoptimizer::patch_size());
    }
    if (!instr->IsLazyBailout() && !instr->IsGap()) {
      safepoints_.BumpLastLazySafepointIndex();
    }
  }
  
  
  void LCodeGen::GenerateBodyInstructionPost(LInstruction* instr) {
    if (FLAG_debug_code && FLAG_enable_slow_asserts && instr->HasResult() &&
        instr->hydrogen_value()->representation().IsInteger32() &&
        instr->result()->IsRegister()) {
      __ AssertZeroExtended(ToRegister(instr->result()));
    }
  
    if (instr->HasResult() && instr->MustSignExtendResult(chunk())) {
      // We sign extend the dehoisted key at the definition point when the pointer
      // size is 64-bit. For x32 port, we sign extend the dehoisted key at the use
      // points and MustSignExtendResult is always false. We can't use
      // STATIC_ASSERT here as the pointer size is 32-bit for x32.
      DCHECK(kPointerSize == kInt64Size);
      if (instr->result()->IsRegister()) {
        Register result_reg = ToRegister(instr->result());
        __ movsxlq(result_reg, result_reg);
      } else {
        // Sign extend the 32bit result in the stack slots.
        DCHECK(instr->result()->IsStackSlot());
        Operand src = ToOperand(instr->result());
        __ movsxlq(kScratchRegister, src);
        __ movq(src, kScratchRegister);
      }
    }
  }
  
  
  bool LCodeGen::GenerateJumpTable() {
    if (jump_table_.length() == 0) return !is_aborted();
  
    Label needs_frame;
    Comment(";;; -------------------- Jump table --------------------");
    for (int i = 0; i < jump_table_.length(); i++) {
      Deoptimizer::JumpTableEntry* table_entry = &jump_table_[i];
      __ bind(&table_entry->label);
      Address entry = table_entry->address;
      DeoptComment(table_entry->deopt_info);
      if (table_entry->needs_frame) {
        DCHECK(!info()->saves_caller_doubles());
        __ Move(kScratchRegister, ExternalReference::ForDeoptEntry(entry));
        __ call(&needs_frame);
      } else {
        if (info()->saves_caller_doubles()) {
          DCHECK(info()->IsStub());
          RestoreCallerDoubles();
        }
        __ call(entry, RelocInfo::RUNTIME_ENTRY);
      }
      info()->LogDeoptCallPosition(masm()->pc_offset(),
                                   table_entry->deopt_info.inlining_id);
    }
  
    if (needs_frame.is_linked()) {
      __ bind(&needs_frame);
      /* stack layout
         4: return address  <-- rsp
         3: garbage
         2: garbage
         1: garbage
         0: garbage
      */
      // Reserve space for context and stub marker.
      __ subp(rsp, Immediate(2 * kPointerSize));
      __ Push(MemOperand(rsp, 2 * kPointerSize));  // Copy return address.
      __ Push(kScratchRegister);  // Save entry address for ret(0)
  
      /* stack layout
         4: return address
         3: garbage
         2: garbage
         1: return address
         0: entry address  <-- rsp
      */
  
      // Remember context pointer.
      __ movp(kScratchRegister,
              MemOperand(rbp, StandardFrameConstants::kContextOffset));
      // Save context pointer into the stack frame.
      __ movp(MemOperand(rsp, 3 * kPointerSize), kScratchRegister);
  
      // Create a stack frame.
      __ movp(MemOperand(rsp, 4 * kPointerSize), rbp);
      __ leap(rbp, MemOperand(rsp, 4 * kPointerSize));
  
      // This variant of deopt can only be used with stubs. Since we don't
      // have a function pointer to install in the stack frame that we're
      // building, install a special marker there instead.
      DCHECK(info()->IsStub());
      __ Move(MemOperand(rsp, 2 * kPointerSize), Smi::FromInt(StackFrame::STUB));
  
      /* stack layout
         4: old rbp
         3: context pointer
         2: stub marker
         1: return address
         0: entry address  <-- rsp
      */
      __ ret(0);
    }
  
    return !is_aborted();
  }
  
  
  bool LCodeGen::GenerateDeferredCode() {
    DCHECK(is_generating());
    if (deferred_.length() > 0) {
      for (int i = 0; !is_aborted() && i < deferred_.length(); i++) {
        LDeferredCode* code = deferred_[i];
  
        HValue* value =
            instructions_->at(code->instruction_index())->hydrogen_value();
        RecordAndWritePosition(
            chunk()->graph()->SourcePositionToScriptPosition(value->position()));
  
        Comment(";;; <@%d,#%d> "
                "-------------------- Deferred %s --------------------",
                code->instruction_index(),
                code->instr()->hydrogen_value()->id(),
                code->instr()->Mnemonic());
        __ bind(code->entry());
        if (NeedsDeferredFrame()) {
          Comment(";;; Build frame");
          DCHECK(!frame_is_built_);
          DCHECK(info()->IsStub());
          frame_is_built_ = true;
          // Build the frame in such a way that esi isn't trashed.
          __ pushq(rbp);  // Caller's frame pointer.
          __ Push(Operand(rbp, StandardFrameConstants::kContextOffset));
          __ Push(Smi::FromInt(StackFrame::STUB));
          __ leap(rbp, Operand(rsp, 2 * kPointerSize));
          Comment(";;; Deferred code");
        }
        code->Generate();
        if (NeedsDeferredFrame()) {
          __ bind(code->done());
          Comment(";;; Destroy frame");
          DCHECK(frame_is_built_);
          frame_is_built_ = false;
          __ movp(rsp, rbp);
          __ popq(rbp);
        }
        __ jmp(code->exit());
      }
    }
  
    // Deferred code is the last part of the instruction sequence. Mark
    // the generated code as done unless we bailed out.
    if (!is_aborted()) status_ = DONE;
    return !is_aborted();
  }
  
  
  bool LCodeGen::GenerateSafepointTable() {
    DCHECK(is_done());
    safepoints_.Emit(masm(), GetStackSlotCount());
    return !is_aborted();
  }
  
  
  Register LCodeGen::ToRegister(int index) const {
    return Register::FromAllocationIndex(index);
  }
  
  
  XMMRegister LCodeGen::ToDoubleRegister(int index) const {
    return XMMRegister::FromAllocationIndex(index);
  }
  
  
  Register LCodeGen::ToRegister(LOperand* op) const {
    DCHECK(op->IsRegister());
    return ToRegister(op->index());
  }
  
  
  XMMRegister LCodeGen::ToDoubleRegister(LOperand* op) const {
    DCHECK(op->IsDoubleRegister());
    return ToDoubleRegister(op->index());
  }
  
  
  bool LCodeGen::IsInteger32Constant(LConstantOperand* op) const {
    return chunk_->LookupLiteralRepresentation(op).IsSmiOrInteger32();
  }
  
  
  bool LCodeGen::IsDehoistedKeyConstant(LConstantOperand* op) const {
    return op->IsConstantOperand() &&
        chunk_->IsDehoistedKey(chunk_->LookupConstant(op));
  }
  
  
  bool LCodeGen::IsSmiConstant(LConstantOperand* op) const {
    return chunk_->LookupLiteralRepresentation(op).IsSmi();
  }
  
  
  int32_t LCodeGen::ToInteger32(LConstantOperand* op) const {
    return ToRepresentation(op, Representation::Integer32());
  }
  
  
  int32_t LCodeGen::ToRepresentation(LConstantOperand* op,
                                     const Representation& r) const {
    HConstant* constant = chunk_->LookupConstant(op);
    int32_t value = constant->Integer32Value();
    if (r.IsInteger32()) return value;
    DCHECK(SmiValuesAre31Bits() && r.IsSmiOrTagged());
    return static_cast<int32_t>(reinterpret_cast<intptr_t>(Smi::FromInt(value)));
  }
  
  
  Smi* LCodeGen::ToSmi(LConstantOperand* op) const {
    HConstant* constant = chunk_->LookupConstant(op);
    return Smi::FromInt(constant->Integer32Value());
  }
  
  
  double LCodeGen::ToDouble(LConstantOperand* op) const {
    HConstant* constant = chunk_->LookupConstant(op);
    DCHECK(constant->HasDoubleValue());
    return constant->DoubleValue();
  }
  
  
  ExternalReference LCodeGen::ToExternalReference(LConstantOperand* op) const {
    HConstant* constant = chunk_->LookupConstant(op);
    DCHECK(constant->HasExternalReferenceValue());
    return constant->ExternalReferenceValue();
  }
  
  
  Handle<Object> LCodeGen::ToHandle(LConstantOperand* op) const {
    HConstant* constant = chunk_->LookupConstant(op);
    DCHECK(chunk_->LookupLiteralRepresentation(op).IsSmiOrTagged());
    return constant->handle(isolate());
  }
  
  
  static int ArgumentsOffsetWithoutFrame(int index) {
    DCHECK(index < 0);
    return -(index + 1) * kPointerSize + kPCOnStackSize;
  }
  
  
  Operand LCodeGen::ToOperand(LOperand* op) const {
    // Does not handle registers. In X64 assembler, plain registers are not
    // representable as an Operand.
    DCHECK(op->IsStackSlot() || op->IsDoubleStackSlot());
    if (NeedsEagerFrame()) {
      return Operand(rbp, StackSlotOffset(op->index()));
    } else {
      // Retrieve parameter without eager stack-frame relative to the
      // stack-pointer.
      return Operand(rsp, ArgumentsOffsetWithoutFrame(op->index()));
    }
  }
  
  
  void LCodeGen::WriteTranslation(LEnvironment* environment,
                                  Translation* translation) {
    if (environment == NULL) return;
  
    // The translation includes one command per value in the environment.
    int translation_size = environment->translation_size();
    // The output frame height does not include the parameters.
    int height = translation_size - environment->parameter_count();
  
    WriteTranslation(environment->outer(), translation);
    bool has_closure_id = !info()->closure().is_null() &&
        !info()->closure().is_identical_to(environment->closure());
    int closure_id = has_closure_id
        ? DefineDeoptimizationLiteral(environment->closure())
        : Translation::kSelfLiteralId;
  
    switch (environment->frame_type()) {
      case JS_FUNCTION:
        translation->BeginJSFrame(environment->ast_id(), closure_id, height);
        break;
      case JS_CONSTRUCT:
        translation->BeginConstructStubFrame(closure_id, translation_size);
        break;
      case JS_GETTER:
        DCHECK(translation_size == 1);
        DCHECK(height == 0);
        translation->BeginGetterStubFrame(closure_id);
        break;
      case JS_SETTER:
        DCHECK(translation_size == 2);
        DCHECK(height == 0);
        translation->BeginSetterStubFrame(closure_id);
        break;
      case ARGUMENTS_ADAPTOR:
        translation->BeginArgumentsAdaptorFrame(closure_id, translation_size);
        break;
      case STUB:
        translation->BeginCompiledStubFrame();
        break;
    }
  
    int object_index = 0;
    int dematerialized_index = 0;
    for (int i = 0; i < translation_size; ++i) {
      LOperand* value = environment->values()->at(i);
      AddToTranslation(environment,
                       translation,
                       value,
                       environment->HasTaggedValueAt(i),
                       environment->HasUint32ValueAt(i),
                       &object_index,
                       &dematerialized_index);
    }
  }
  
  
  void LCodeGen::AddToTranslation(LEnvironment* environment,
                                  Translation* translation,
                                  LOperand* op,
                                  bool is_tagged,
                                  bool is_uint32,
                                  int* object_index_pointer,
                                  int* dematerialized_index_pointer) {
    if (op == LEnvironment::materialization_marker()) {
      int object_index = (*object_index_pointer)++;
      if (environment->ObjectIsDuplicateAt(object_index)) {
        int dupe_of = environment->ObjectDuplicateOfAt(object_index);
        translation->DuplicateObject(dupe_of);
        return;
      }
      int object_length = environment->ObjectLengthAt(object_index);
      if (environment->ObjectIsArgumentsAt(object_index)) {
        translation->BeginArgumentsObject(object_length);
      } else {
        translation->BeginCapturedObject(object_length);
      }
      int dematerialized_index = *dematerialized_index_pointer;
      int env_offset = environment->translation_size() + dematerialized_index;
      *dematerialized_index_pointer += object_length;
      for (int i = 0; i < object_length; ++i) {
        LOperand* value = environment->values()->at(env_offset + i);
        AddToTranslation(environment,
                         translation,
                         value,
                         environment->HasTaggedValueAt(env_offset + i),
                         environment->HasUint32ValueAt(env_offset + i),
                         object_index_pointer,
                         dematerialized_index_pointer);
      }
      return;
    }
  
    if (op->IsStackSlot()) {
      if (is_tagged) {
        translation->StoreStackSlot(op->index());
      } else if (is_uint32) {
        translation->StoreUint32StackSlot(op->index());
      } else {
        translation->StoreInt32StackSlot(op->index());
      }
    } else if (op->IsDoubleStackSlot()) {
      translation->StoreDoubleStackSlot(op->index());
    } else if (op->IsRegister()) {
      Register reg = ToRegister(op);
      if (is_tagged) {
        translation->StoreRegister(reg);
      } else if (is_uint32) {
        translation->StoreUint32Register(reg);
      } else {
        translation->StoreInt32Register(reg);
      }
    } else if (op->IsDoubleRegister()) {
      XMMRegister reg = ToDoubleRegister(op);
      translation->StoreDoubleRegister(reg);
    } else if (op->IsConstantOperand()) {
      HConstant* constant = chunk()->LookupConstant(LConstantOperand::cast(op));
      int src_index = DefineDeoptimizationLiteral(constant->handle(isolate()));
      translation->StoreLiteral(src_index);
    } else {
      UNREACHABLE();
    }
  }
  
  
  void LCodeGen::CallCodeGeneric(Handle<Code> code,
                                 RelocInfo::Mode mode,
                                 LInstruction* instr,
                                 SafepointMode safepoint_mode,
                                 int argc) {
    DCHECK(instr != NULL);
    __ call(code, mode);
    RecordSafepointWithLazyDeopt(instr, safepoint_mode, argc);
  
    // Signal that we don't inline smi code before these stubs in the
    // optimizing code generator.
    if (code->kind() == Code::BINARY_OP_IC ||
        code->kind() == Code::COMPARE_IC) {
      __ nop();
    }
  }
  
  
  void LCodeGen::CallCode(Handle<Code> code,
                          RelocInfo::Mode mode,
                          LInstruction* instr) {
    CallCodeGeneric(code, mode, instr, RECORD_SIMPLE_SAFEPOINT, 0);
  }
  
  
  void LCodeGen::CallRuntime(const Runtime::Function* function,
                             int num_arguments,
                             LInstruction* instr,
                             SaveFPRegsMode save_doubles) {
    DCHECK(instr != NULL);
    DCHECK(instr->HasPointerMap());
  
    __ CallRuntime(function, num_arguments, save_doubles);
  
    RecordSafepointWithLazyDeopt(instr, RECORD_SIMPLE_SAFEPOINT, 0);
  }
  
  
  void LCodeGen::LoadContextFromDeferred(LOperand* context) {
    if (context->IsRegister()) {
      if (!ToRegister(context).is(rsi)) {
        __ movp(rsi, ToRegister(context));
      }
    } else if (context->IsStackSlot()) {
      __ movp(rsi, ToOperand(context));
    } else if (context->IsConstantOperand()) {
      HConstant* constant =
          chunk_->LookupConstant(LConstantOperand::cast(context));
      __ Move(rsi, Handle<Object>::cast(constant->handle(isolate())));
    } else {
      UNREACHABLE();
    }
  }
  
  
  
  void LCodeGen::CallRuntimeFromDeferred(Runtime::FunctionId id,
                                         int argc,
                                         LInstruction* instr,
                                         LOperand* context) {
    LoadContextFromDeferred(context);
  
    __ CallRuntimeSaveDoubles(id);
    RecordSafepointWithRegisters(
        instr->pointer_map(), argc, Safepoint::kNoLazyDeopt);
  }
  
  
  void LCodeGen::RegisterEnvironmentForDeoptimization(LEnvironment* environment,
                                                      Safepoint::DeoptMode mode) {
    environment->set_has_been_used();
    if (!environment->HasBeenRegistered()) {
      // Physical stack frame layout:
      // -x ............. -4  0 ..................................... y
      // [incoming arguments] [spill slots] [pushed outgoing arguments]
  
      // Layout of the environment:
      // 0 ..................................................... size-1
      // [parameters] [locals] [expression stack including arguments]
  
      // Layout of the translation:
      // 0 ........................................................ size - 1 + 4
      // [expression stack including arguments] [locals] [4 words] [parameters]
      // |>------------  translation_size ------------<|
  
      int frame_count = 0;
      int jsframe_count = 0;
      for (LEnvironment* e = environment; e != NULL; e = e->outer()) {
        ++frame_count;
        if (e->frame_type() == JS_FUNCTION) {
          ++jsframe_count;
        }
      }
      Translation translation(&translations_, frame_count, jsframe_count, zone());
      WriteTranslation(environment, &translation);
      int deoptimization_index = deoptimizations_.length();
      int pc_offset = masm()->pc_offset();
      environment->Register(deoptimization_index,
                            translation.index(),
                            (mode == Safepoint::kLazyDeopt) ? pc_offset : -1);
      deoptimizations_.Add(environment, environment->zone());
    }
  }
  
  
  void LCodeGen::DeoptimizeIf(Condition cc, LInstruction* instr,
                              Deoptimizer::DeoptReason deopt_reason,
                              Deoptimizer::BailoutType bailout_type) {
    LEnvironment* environment = instr->environment();
    RegisterEnvironmentForDeoptimization(environment, Safepoint::kNoLazyDeopt);
    DCHECK(environment->HasBeenRegistered());
    int id = environment->deoptimization_index();
    DCHECK(info()->IsOptimizing() || info()->IsStub());
    Address entry =
        Deoptimizer::GetDeoptimizationEntry(isolate(), id, bailout_type);
    if (entry == NULL) {
      Abort(kBailoutWasNotPrepared);
      return;
    }
  
    if (DeoptEveryNTimes()) {
      ExternalReference count = ExternalReference::stress_deopt_count(isolate());
      Label no_deopt;
      __ pushfq();
      __ pushq(rax);
      Operand count_operand = masm()->ExternalOperand(count, kScratchRegister);
      __ movl(rax, count_operand);
      __ subl(rax, Immediate(1));
      __ j(not_zero, &no_deopt, Label::kNear);
      if (FLAG_trap_on_deopt) __ int3();
      __ movl(rax, Immediate(FLAG_deopt_every_n_times));
      __ movl(count_operand, rax);
      __ popq(rax);
      __ popfq();
      DCHECK(frame_is_built_);
      __ call(entry, RelocInfo::RUNTIME_ENTRY);
      __ bind(&no_deopt);
      __ movl(count_operand, rax);
      __ popq(rax);
      __ popfq();
    }
  
    if (info()->ShouldTrapOnDeopt()) {
      Label done;
      if (cc != no_condition) {
        __ j(NegateCondition(cc), &done, Label::kNear);
      }
      __ int3();
      __ bind(&done);
    }
  
    Deoptimizer::DeoptInfo deopt_info = MakeDeoptInfo(instr, deopt_reason);
  
    DCHECK(info()->IsStub() || frame_is_built_);
    // Go through jump table if we need to handle condition, build frame, or
    // restore caller doubles.
    if (cc == no_condition && frame_is_built_ &&
        !info()->saves_caller_doubles()) {
      DeoptComment(deopt_info);
      __ call(entry, RelocInfo::RUNTIME_ENTRY);
      info()->LogDeoptCallPosition(masm()->pc_offset(), deopt_info.inlining_id);
    } else {
      Deoptimizer::JumpTableEntry table_entry(entry, deopt_info, bailout_type,
                                              !frame_is_built_);
      // We often have several deopts to the same entry, reuse the last
      // jump entry if this is the case.
      if (FLAG_trace_deopt || isolate()->cpu_profiler()->is_profiling() ||
          jump_table_.is_empty() ||
          !table_entry.IsEquivalentTo(jump_table_.last())) {
        jump_table_.Add(table_entry, zone());
      }
      if (cc == no_condition) {
        __ jmp(&jump_table_.last().label);
      } else {
        __ j(cc, &jump_table_.last().label);
      }
    }
  }
  
  
  void LCodeGen::DeoptimizeIf(Condition cc, LInstruction* instr,
                              Deoptimizer::DeoptReason deopt_reason) {
    Deoptimizer::BailoutType bailout_type = info()->IsStub()
        ? Deoptimizer::LAZY
        : Deoptimizer::EAGER;
    DeoptimizeIf(cc, instr, deopt_reason, bailout_type);
  }
  
  
  void LCodeGen::PopulateDeoptimizationData(Handle<Code> code) {
    int length = deoptimizations_.length();
    if (length == 0) return;
    Handle<DeoptimizationInputData> data =
        DeoptimizationInputData::New(isolate(), length, TENURED);
  
    Handle<ByteArray> translations =
        translations_.CreateByteArray(isolate()->factory());
    data->SetTranslationByteArray(*translations);
    data->SetInlinedFunctionCount(Smi::FromInt(inlined_function_count_));
    data->SetOptimizationId(Smi::FromInt(info_->optimization_id()));
    if (info_->IsOptimizing()) {
      // Reference to shared function info does not change between phases.
      AllowDeferredHandleDereference allow_handle_dereference;
      data->SetSharedFunctionInfo(*info_->shared_info());
    } else {
      data->SetSharedFunctionInfo(Smi::FromInt(0));
    }
    data->SetWeakCellCache(Smi::FromInt(0));
  
    Handle<FixedArray> literals =
        factory()->NewFixedArray(deoptimization_literals_.length(), TENURED);
    { AllowDeferredHandleDereference copy_handles;
      for (int i = 0; i < deoptimization_literals_.length(); i++) {
        literals->set(i, *deoptimization_literals_[i]);
      }
      data->SetLiteralArray(*literals);
    }
  
    data->SetOsrAstId(Smi::FromInt(info_->osr_ast_id().ToInt()));
    data->SetOsrPcOffset(Smi::FromInt(osr_pc_offset_));
  
    // Populate the deoptimization entries.
    for (int i = 0; i < length; i++) {
      LEnvironment* env = deoptimizations_[i];
      data->SetAstId(i, env->ast_id());
      data->SetTranslationIndex(i, Smi::FromInt(env->translation_index()));
      data->SetArgumentsStackHeight(i,
                                    Smi::FromInt(env->arguments_stack_height()));
      data->SetPc(i, Smi::FromInt(env->pc_offset()));
    }
    code->set_deoptimization_data(*data);
  }
  
  
  int LCodeGen::DefineDeoptimizationLiteral(Handle<Object> literal) {
    int result = deoptimization_literals_.length();
    for (int i = 0; i < deoptimization_literals_.length(); ++i) {
      if (deoptimization_literals_[i].is_identical_to(literal)) return i;
    }
    deoptimization_literals_.Add(literal, zone());
    return result;
  }
  
  
  void LCodeGen::PopulateDeoptimizationLiteralsWithInlinedFunctions() {
    DCHECK(deoptimization_literals_.length() == 0);
  
    const ZoneList<Handle<JSFunction> >* inlined_closures =
        chunk()->inlined_closures();
  
    for (int i = 0, length = inlined_closures->length();
         i < length;
         i++) {
      DefineDeoptimizationLiteral(inlined_closures->at(i));
    }
  
    inlined_function_count_ = deoptimization_literals_.length();
  }
  
  
  void LCodeGen::RecordSafepointWithLazyDeopt(
      LInstruction* instr, SafepointMode safepoint_mode, int argc) {
    if (safepoint_mode == RECORD_SIMPLE_SAFEPOINT) {
      RecordSafepoint(instr->pointer_map(), Safepoint::kLazyDeopt);
    } else {
      DCHECK(safepoint_mode == RECORD_SAFEPOINT_WITH_REGISTERS);
      RecordSafepointWithRegisters(
          instr->pointer_map(), argc, Safepoint::kLazyDeopt);
    }
  }
  
  
  void LCodeGen::RecordSafepoint(
      LPointerMap* pointers,
      Safepoint::Kind kind,
      int arguments,
      Safepoint::DeoptMode deopt_mode) {
    DCHECK(kind == expected_safepoint_kind_);
  
    const ZoneList<LOperand*>* operands = pointers->GetNormalizedOperands();
  
    Safepoint safepoint = safepoints_.DefineSafepoint(masm(),
        kind, arguments, deopt_mode);
    for (int i = 0; i < operands->length(); i++) {
      LOperand* pointer = operands->at(i);
      if (pointer->IsStackSlot()) {
        safepoint.DefinePointerSlot(pointer->index(), zone());
      } else if (pointer->IsRegister() && (kind & Safepoint::kWithRegisters)) {
        safepoint.DefinePointerRegister(ToRegister(pointer), zone());
      }
    }
  }
  
  
  void LCodeGen::RecordSafepoint(LPointerMap* pointers,
                                 Safepoint::DeoptMode deopt_mode) {
    RecordSafepoint(pointers, Safepoint::kSimple, 0, deopt_mode);
  }
  
  
  void LCodeGen::RecordSafepoint(Safepoint::DeoptMode deopt_mode) {
    LPointerMap empty_pointers(zone());
    RecordSafepoint(&empty_pointers, deopt_mode);
  }
  
  
  void LCodeGen::RecordSafepointWithRegisters(LPointerMap* pointers,
                                              int arguments,
                                              Safepoint::DeoptMode deopt_mode) {
    RecordSafepoint(pointers, Safepoint::kWithRegisters, arguments, deopt_mode);
  }
  
  
  void LCodeGen::RecordAndWritePosition(int position) {
    if (position == RelocInfo::kNoPosition) return;
    masm()->positions_recorder()->RecordPosition(position);
    masm()->positions_recorder()->WriteRecordedPositions();
  }
  
  
  static const char* LabelType(LLabel* label) {
    if (label->is_loop_header()) return " (loop header)";
    if (label->is_osr_entry()) return " (OSR entry)";
    return "";
  }
  
  
  void LCodeGen::DoLabel(LLabel* label) {
    Comment(";;; <@%d,#%d> -------------------- B%d%s --------------------",
            current_instruction_,
            label->hydrogen_value()->id(),
            label->block_id(),
            LabelType(label));
    __ bind(label->label());
    current_block_ = label->block_id();
    DoGap(label);
  }
  
  
  void LCodeGen::DoParallelMove(LParallelMove* move) {
    resolver_.Resolve(move);
  }
  
  
  void LCodeGen::DoGap(LGap* gap) {
    for (int i = LGap::FIRST_INNER_POSITION;
         i <= LGap::LAST_INNER_POSITION;
         i++) {
      LGap::InnerPosition inner_pos = static_cast<LGap::InnerPosition>(i);
      LParallelMove* move = gap->GetParallelMove(inner_pos);
      if (move != NULL) DoParallelMove(move);
    }
  }
  
  
  void LCodeGen::DoInstructionGap(LInstructionGap* instr) {
    DoGap(instr);
  }
  
  
  void LCodeGen::DoParameter(LParameter* instr) {
    // Nothing to do.
  }
  
  
  void LCodeGen::DoCallStub(LCallStub* instr) {
    DCHECK(ToRegister(instr->context()).is(rsi));
    DCHECK(ToRegister(instr->result()).is(rax));
    switch (instr->hydrogen()->major_key()) {
      case CodeStub::RegExpExec: {
        RegExpExecStub stub(isolate());
        CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
        break;
      }
      case CodeStub::SubString: {
        SubStringStub stub(isolate());
        CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
        break;
      }
      case CodeStub::StringCompare: {
        StringCompareStub stub(isolate());
        CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
        break;
      }
      default:
        UNREACHABLE();
    }
  }
  
  
  void LCodeGen::DoUnknownOSRValue(LUnknownOSRValue* instr) {
    GenerateOsrPrologue();
  }
  
  
  void LCodeGen::DoModByPowerOf2I(LModByPowerOf2I* instr) {
    Register dividend = ToRegister(instr->dividend());
    int32_t divisor = instr->divisor();
    DCHECK(dividend.is(ToRegister(instr->result())));
  
    // Theoretically, a variation of the branch-free code for integer division by
    // a power of 2 (calculating the remainder via an additional multiplication
    // (which gets simplified to an 'and') and subtraction) should be faster, and
    // this is exactly what GCC and clang emit. Nevertheless, benchmarks seem to
    // indicate that positive dividends are heavily favored, so the branching
    // version performs better.
    HMod* hmod = instr->hydrogen();
    int32_t mask = divisor < 0 ? -(divisor + 1) : (divisor - 1);
    Label dividend_is_not_negative, done;
    if (hmod->CheckFlag(HValue::kLeftCanBeNegative)) {
      __ testl(dividend, dividend);
      __ j(not_sign, &dividend_is_not_negative, Label::kNear);
      // Note that this is correct even for kMinInt operands.
      __ negl(dividend);
      __ andl(dividend, Immediate(mask));
      __ negl(dividend);
      if (hmod->CheckFlag(HValue::kBailoutOnMinusZero)) {
        DeoptimizeIf(zero, instr, Deoptimizer::kMinusZero);
      }
      __ jmp(&done, Label::kNear);
    }
  
    __ bind(&dividend_is_not_negative);
    __ andl(dividend, Immediate(mask));
    __ bind(&done);
  }
  
  
  void LCodeGen::DoModByConstI(LModByConstI* instr) {
    Register dividend = ToRegister(instr->dividend());
    int32_t divisor = instr->divisor();
    DCHECK(ToRegister(instr->result()).is(rax));
  
    if (divisor == 0) {
      DeoptimizeIf(no_condition, instr, Deoptimizer::kDivisionByZero);
      return;
    }
  
    __ TruncatingDiv(dividend, Abs(divisor));
    __ imull(rdx, rdx, Immediate(Abs(divisor)));
    __ movl(rax, dividend);
    __ subl(rax, rdx);
  
    // Check for negative zero.
    HMod* hmod = instr->hydrogen();
    if (hmod->CheckFlag(HValue::kBailoutOnMinusZero)) {
      Label remainder_not_zero;
      __ j(not_zero, &remainder_not_zero, Label::kNear);
      __ cmpl(dividend, Immediate(0));
      DeoptimizeIf(less, instr, Deoptimizer::kMinusZero);
      __ bind(&remainder_not_zero);
    }
  }
  
  
  void LCodeGen::DoModI(LModI* instr) {
    HMod* hmod = instr->hydrogen();
  
    Register left_reg = ToRegister(instr->left());
    DCHECK(left_reg.is(rax));
    Register right_reg = ToRegister(instr->right());
    DCHECK(!right_reg.is(rax));
    DCHECK(!right_reg.is(rdx));
    Register result_reg = ToRegister(instr->result());
    DCHECK(result_reg.is(rdx));
  
    Label done;
    // Check for x % 0, idiv would signal a divide error. We have to
    // deopt in this case because we can't return a NaN.
    if (hmod->CheckFlag(HValue::kCanBeDivByZero)) {
      __ testl(right_reg, right_reg);
      DeoptimizeIf(zero, instr, Deoptimizer::kDivisionByZero);
    }
  
    // Check for kMinInt % -1, idiv would signal a divide error. We
    // have to deopt if we care about -0, because we can't return that.
    if (hmod->CheckFlag(HValue::kCanOverflow)) {
      Label no_overflow_possible;
      __ cmpl(left_reg, Immediate(kMinInt));
      __ j(not_zero, &no_overflow_possible, Label::kNear);
      __ cmpl(right_reg, Immediate(-1));
      if (hmod->CheckFlag(HValue::kBailoutOnMinusZero)) {
        DeoptimizeIf(equal, instr, Deoptimizer::kMinusZero);
      } else {
        __ j(not_equal, &no_overflow_possible, Label::kNear);
        __ Set(result_reg, 0);
        __ jmp(&done, Label::kNear);
      }
      __ bind(&no_overflow_possible);
    }
  
    // Sign extend dividend in eax into edx:eax, since we are using only the low
    // 32 bits of the values.
    __ cdq();
  
    // If we care about -0, test if the dividend is <0 and the result is 0.
    if (hmod->CheckFlag(HValue::kBailoutOnMinusZero)) {
      Label positive_left;
      __ testl(left_reg, left_reg);
      __ j(not_sign, &positive_left, Label::kNear);
      __ idivl(right_reg);
      __ testl(result_reg, result_reg);
      DeoptimizeIf(zero, instr, Deoptimizer::kMinusZero);
      __ jmp(&done, Label::kNear);
      __ bind(&positive_left);
    }
    __ idivl(right_reg);
    __ bind(&done);
  }
  
  
  void LCodeGen::DoFlooringDivByPowerOf2I(LFlooringDivByPowerOf2I* instr) {
    Register dividend = ToRegister(instr->dividend());
    int32_t divisor = instr->divisor();
    DCHECK(dividend.is(ToRegister(instr->result())));
  
    // If the divisor is positive, things are easy: There can be no deopts and we
    // can simply do an arithmetic right shift.
    if (divisor == 1) return;
    int32_t shift = WhichPowerOf2Abs(divisor);
    if (divisor > 1) {
      __ sarl(dividend, Immediate(shift));
      return;
    }
  
    // If the divisor is negative, we have to negate and handle edge cases.
    __ negl(dividend);
    if (instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero)) {
      DeoptimizeIf(zero, instr, Deoptimizer::kMinusZero);
    }
  
    // Dividing by -1 is basically negation, unless we overflow.
    if (divisor == -1) {
      if (instr->hydrogen()->CheckFlag(HValue::kLeftCanBeMinInt)) {
        DeoptimizeIf(overflow, instr, Deoptimizer::kOverflow);
      }
      return;
    }
  
    // If the negation could not overflow, simply shifting is OK.
    if (!instr->hydrogen()->CheckFlag(HValue::kLeftCanBeMinInt)) {
      __ sarl(dividend, Immediate(shift));
      return;
    }
  
    Label not_kmin_int, done;
    __ j(no_overflow, &not_kmin_int, Label::kNear);
    __ movl(dividend, Immediate(kMinInt / divisor));
    __ jmp(&done, Label::kNear);
    __ bind(&not_kmin_int);
    __ sarl(dividend, Immediate(shift));
    __ bind(&done);
  }
  
  
  void LCodeGen::DoFlooringDivByConstI(LFlooringDivByConstI* instr) {
    Register dividend = ToRegister(instr->dividend());
    int32_t divisor = instr->divisor();
    DCHECK(ToRegister(instr->result()).is(rdx));
  
    if (divisor == 0) {
      DeoptimizeIf(no_condition, instr, Deoptimizer::kDivisionByZero);
      return;
    }
  
    // Check for (0 / -x) that will produce negative zero.
    HMathFloorOfDiv* hdiv = instr->hydrogen();
    if (hdiv->CheckFlag(HValue::kBailoutOnMinusZero) && divisor < 0) {
      __ testl(dividend, dividend);
      DeoptimizeIf(zero, instr, Deoptimizer::kMinusZero);
    }
  
    // Easy case: We need no dynamic check for the dividend and the flooring
    // division is the same as the truncating division.
    if ((divisor > 0 && !hdiv->CheckFlag(HValue::kLeftCanBeNegative)) ||
        (divisor < 0 && !hdiv->CheckFlag(HValue::kLeftCanBePositive))) {
      __ TruncatingDiv(dividend, Abs(divisor));
      if (divisor < 0) __ negl(rdx);
      return;
    }
  
    // In the general case we may need to adjust before and after the truncating
    // division to get a flooring division.
    Register temp = ToRegister(instr->temp3());
    DCHECK(!temp.is(dividend) && !temp.is(rax) && !temp.is(rdx));
    Label needs_adjustment, done;
    __ cmpl(dividend, Immediate(0));
    __ j(divisor > 0 ? less : greater, &needs_adjustment, Label::kNear);
    __ TruncatingDiv(dividend, Abs(divisor));
    if (divisor < 0) __ negl(rdx);
    __ jmp(&done, Label::kNear);
    __ bind(&needs_adjustment);
    __ leal(temp, Operand(dividend, divisor > 0 ? 1 : -1));
    __ TruncatingDiv(temp, Abs(divisor));
    if (divisor < 0) __ negl(rdx);
    __ decl(rdx);
    __ bind(&done);
  }
  
  
  // TODO(svenpanne) Refactor this to avoid code duplication with DoDivI.
  void LCodeGen::DoFlooringDivI(LFlooringDivI* instr) {
    HBinaryOperation* hdiv = instr->hydrogen();
    Register dividend = ToRegister(instr->dividend());
    Register divisor = ToRegister(instr->divisor());
    Register remainder = ToRegister(instr->temp());
    Register result = ToRegister(instr->result());
    DCHECK(dividend.is(rax));
    DCHECK(remainder.is(rdx));
    DCHECK(result.is(rax));
    DCHECK(!divisor.is(rax));
    DCHECK(!divisor.is(rdx));
  
    // Check for x / 0.
    if (hdiv->CheckFlag(HValue::kCanBeDivByZero)) {
      __ testl(divisor, divisor);
      DeoptimizeIf(zero, instr, Deoptimizer::kDivisionByZero);
    }
  
    // Check for (0 / -x) that will produce negative zero.
    if (hdiv->CheckFlag(HValue::kBailoutOnMinusZero)) {
      Label dividend_not_zero;
      __ testl(dividend, dividend);
      __ j(not_zero, &dividend_not_zero, Label::kNear);
      __ testl(divisor, divisor);
      DeoptimizeIf(sign, instr, Deoptimizer::kMinusZero);
      __ bind(&dividend_not_zero);
    }
  
    // Check for (kMinInt / -1).
    if (hdiv->CheckFlag(HValue::kCanOverflow)) {
      Label dividend_not_min_int;
      __ cmpl(dividend, Immediate(kMinInt));
      __ j(not_zero, &dividend_not_min_int, Label::kNear);
      __ cmpl(divisor, Immediate(-1));
      DeoptimizeIf(zero, instr, Deoptimizer::kOverflow);
      __ bind(&dividend_not_min_int);
    }
  
    // Sign extend to rdx (= remainder).
    __ cdq();
    __ idivl(divisor);
  
    Label done;
    __ testl(remainder, remainder);
    __ j(zero, &done, Label::kNear);
    __ xorl(remainder, divisor);
    __ sarl(remainder, Immediate(31));
    __ addl(result, remainder);
    __ bind(&done);
  }
  
  
  void LCodeGen::DoDivByPowerOf2I(LDivByPowerOf2I* instr) {
    Register dividend = ToRegister(instr->dividend());
    int32_t divisor = instr->divisor();
    Register result = ToRegister(instr->result());
    DCHECK(divisor == kMinInt || base::bits::IsPowerOfTwo32(Abs(divisor)));
    DCHECK(!result.is(dividend));
  
    // Check for (0 / -x) that will produce negative zero.
    HDiv* hdiv = instr->hydrogen();
    if (hdiv->CheckFlag(HValue::kBailoutOnMinusZero) && divisor < 0) {
      __ testl(dividend, dividend);
      DeoptimizeIf(zero, instr, Deoptimizer::kMinusZero);
    }
    // Check for (kMinInt / -1).
    if (hdiv->CheckFlag(HValue::kCanOverflow) && divisor == -1) {
      __ cmpl(dividend, Immediate(kMinInt));
      DeoptimizeIf(zero, instr, Deoptimizer::kOverflow);
    }
    // Deoptimize if remainder will not be 0.
    if (!hdiv->CheckFlag(HInstruction::kAllUsesTruncatingToInt32) &&
        divisor != 1 && divisor != -1) {
      int32_t mask = divisor < 0 ? -(divisor + 1) : (divisor - 1);
      __ testl(dividend, Immediate(mask));
      DeoptimizeIf(not_zero, instr, Deoptimizer::kLostPrecision);
    }
    __ Move(result, dividend);
    int32_t shift = WhichPowerOf2Abs(divisor);
    if (shift > 0) {
      // The arithmetic shift is always OK, the 'if' is an optimization only.
      if (shift > 1) __ sarl(result, Immediate(31));
      __ shrl(result, Immediate(32 - shift));
      __ addl(result, dividend);
      __ sarl(result, Immediate(shift));
    }
    if (divisor < 0) __ negl(result);
  }
  
  
  void LCodeGen::DoDivByConstI(LDivByConstI* instr) {
    Register dividend = ToRegister(instr->dividend());
    int32_t divisor = instr->divisor();
    DCHECK(ToRegister(instr->result()).is(rdx));
  
    if (divisor == 0) {
      DeoptimizeIf(no_condition, instr, Deoptimizer::kDivisionByZero);
      return;
    }
  
    // Check for (0 / -x) that will produce negative zero.
    HDiv* hdiv = instr->hydrogen();
    if (hdiv->CheckFlag(HValue::kBailoutOnMinusZero) && divisor < 0) {
      __ testl(dividend, dividend);
      DeoptimizeIf(zero, instr, Deoptimizer::kMinusZero);
    }
  
    __ TruncatingDiv(dividend, Abs(divisor));
    if (divisor < 0) __ negl(rdx);
  
    if (!hdiv->CheckFlag(HInstruction::kAllUsesTruncatingToInt32)) {
      __ movl(rax, rdx);
      __ imull(rax, rax, Immediate(divisor));
      __ subl(rax, dividend);
      DeoptimizeIf(not_equal, instr, Deoptimizer::kLostPrecision);
    }
  }
  
  
  // TODO(svenpanne) Refactor this to avoid code duplication with DoFlooringDivI.
  void LCodeGen::DoDivI(LDivI* instr) {
    HBinaryOperation* hdiv = instr->hydrogen();
    Register dividend = ToRegister(instr->dividend());
    Register divisor = ToRegister(instr->divisor());
    Register remainder = ToRegister(instr->temp());
    DCHECK(dividend.is(rax));
    DCHECK(remainder.is(rdx));
    DCHECK(ToRegister(instr->result()).is(rax));
    DCHECK(!divisor.is(rax));
    DCHECK(!divisor.is(rdx));
  
    // Check for x / 0.
    if (hdiv->CheckFlag(HValue::kCanBeDivByZero)) {
      __ testl(divisor, divisor);
      DeoptimizeIf(zero, instr, Deoptimizer::kDivisionByZero);
    }
  
    // Check for (0 / -x) that will produce negative zero.
    if (hdiv->CheckFlag(HValue::kBailoutOnMinusZero)) {
      Label dividend_not_zero;
      __ testl(dividend, dividend);
      __ j(not_zero, &dividend_not_zero, Label::kNear);
      __ testl(divisor, divisor);
      DeoptimizeIf(sign, instr, Deoptimizer::kMinusZero);
      __ bind(&dividend_not_zero);
    }
  
    // Check for (kMinInt / -1).
    if (hdiv->CheckFlag(HValue::kCanOverflow)) {
      Label dividend_not_min_int;
      __ cmpl(dividend, Immediate(kMinInt));
      __ j(not_zero, &dividend_not_min_int, Label::kNear);
      __ cmpl(divisor, Immediate(-1));
      DeoptimizeIf(zero, instr, Deoptimizer::kOverflow);
      __ bind(&dividend_not_min_int);
    }
  
    // Sign extend to rdx (= remainder).
    __ cdq();
    __ idivl(divisor);
  
    if (!hdiv->CheckFlag(HValue::kAllUsesTruncatingToInt32)) {
      // Deoptimize if remainder is not 0.
      __ testl(remainder, remainder);
      DeoptimizeIf(not_zero, instr, Deoptimizer::kLostPrecision);
    }
  }
  
  
  void LCodeGen::DoMulI(LMulI* instr) {
    Register left = ToRegister(instr->left());
    LOperand* right = instr->right();
  
    if (instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero)) {
      if (instr->hydrogen_value()->representation().IsSmi()) {
        __ movp(kScratchRegister, left);
      } else {
        __ movl(kScratchRegister, left);
      }
    }
  
    bool can_overflow =
        instr->hydrogen()->CheckFlag(HValue::kCanOverflow);
    if (right->IsConstantOperand()) {
      int32_t right_value = ToInteger32(LConstantOperand::cast(right));
      if (right_value == -1) {
        __ negl(left);
      } else if (right_value == 0) {
        __ xorl(left, left);
      } else if (right_value == 2) {
        __ addl(left, left);
      } else if (!can_overflow) {
        // If the multiplication is known to not overflow, we
        // can use operations that don't set the overflow flag
        // correctly.
        switch (right_value) {
          case 1:
            // Do nothing.
            break;
          case 3:
            __ leal(left, Operand(left, left, times_2, 0));
            break;
          case 4:
            __ shll(left, Immediate(2));
            break;
          case 5:
            __ leal(left, Operand(left, left, times_4, 0));
            break;
          case 8:
            __ shll(left, Immediate(3));
            break;
          case 9:
            __ leal(left, Operand(left, left, times_8, 0));
            break;
          case 16:
            __ shll(left, Immediate(4));
            break;
          default:
            __ imull(left, left, Immediate(right_value));
            break;
        }
      } else {
        __ imull(left, left, Immediate(right_value));
      }
    } else if (right->IsStackSlot()) {
      if (instr->hydrogen_value()->representation().IsSmi()) {
        __ SmiToInteger64(left, left);
        __ imulp(left, ToOperand(right));
      } else {
        __ imull(left, ToOperand(right));
      }
    } else {
      if (instr->hydrogen_value()->representation().IsSmi()) {
        __ SmiToInteger64(left, left);
        __ imulp(left, ToRegister(right));
      } else {
        __ imull(left, ToRegister(right));
      }
    }
  
    if (can_overflow) {
      DeoptimizeIf(overflow, instr, Deoptimizer::kOverflow);
    }
  
    if (instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero)) {
      // Bail out if the result is supposed to be negative zero.
      Label done;
      if (instr->hydrogen_value()->representation().IsSmi()) {
        __ testp(left, left);
      } else {
        __ testl(left, left);
      }
      __ j(not_zero, &done, Label::kNear);
      if (right->IsConstantOperand()) {
        // Constant can't be represented as 32-bit Smi due to immediate size
        // limit.
        DCHECK(SmiValuesAre32Bits()
            ? !instr->hydrogen_value()->representation().IsSmi()
            : SmiValuesAre31Bits());
        if (ToInteger32(LConstantOperand::cast(right)) < 0) {
          DeoptimizeIf(no_condition, instr, Deoptimizer::kMinusZero);
        } else if (ToInteger32(LConstantOperand::cast(right)) == 0) {
          __ cmpl(kScratchRegister, Immediate(0));
          DeoptimizeIf(less, instr, Deoptimizer::kMinusZero);
        }
      } else if (right->IsStackSlot()) {
        if (instr->hydrogen_value()->representation().IsSmi()) {
          __ orp(kScratchRegister, ToOperand(right));
        } else {
          __ orl(kScratchRegister, ToOperand(right));
        }
        DeoptimizeIf(sign, instr, Deoptimizer::kMinusZero);
      } else {
        // Test the non-zero operand for negative sign.
        if (instr->hydrogen_value()->representation().IsSmi()) {
          __ orp(kScratchRegister, ToRegister(right));
        } else {
          __ orl(kScratchRegister, ToRegister(right));
        }
        DeoptimizeIf(sign, instr, Deoptimizer::kMinusZero);
      }
      __ bind(&done);
    }
  }
  
  
  void LCodeGen::DoBitI(LBitI* instr) {
    LOperand* left = instr->left();
    LOperand* right = instr->right();
    DCHECK(left->Equals(instr->result()));
    DCHECK(left->IsRegister());
  
    if (right->IsConstantOperand()) {
      int32_t right_operand =
          ToRepresentation(LConstantOperand::cast(right),
                           instr->hydrogen()->right()->representation());
      switch (instr->op()) {
        case Token::BIT_AND:
          __ andl(ToRegister(left), Immediate(right_operand));
          break;
        case Token::BIT_OR:
          __ orl(ToRegister(left), Immediate(right_operand));
          break;
        case Token::BIT_XOR:
          if (right_operand == int32_t(~0)) {
            __ notl(ToRegister(left));
          } else {
            __ xorl(ToRegister(left), Immediate(right_operand));
          }
          break;
        default:
          UNREACHABLE();
          break;
      }
    } else if (right->IsStackSlot()) {
      switch (instr->op()) {
        case Token::BIT_AND:
          if (instr->IsInteger32()) {
            __ andl(ToRegister(left), ToOperand(right));
          } else {
            __ andp(ToRegister(left), ToOperand(right));
          }
          break;
        case Token::BIT_OR:
          if (instr->IsInteger32()) {
            __ orl(ToRegister(left), ToOperand(right));
          } else {
            __ orp(ToRegister(left), ToOperand(right));
          }
          break;
        case Token::BIT_XOR:
          if (instr->IsInteger32()) {
            __ xorl(ToRegister(left), ToOperand(right));
          } else {
            __ xorp(ToRegister(left), ToOperand(right));
          }
          break;
        default:
          UNREACHABLE();
          break;
      }
    } else {
      DCHECK(right->IsRegister());
      switch (instr->op()) {
        case Token::BIT_AND:
          if (instr->IsInteger32()) {
            __ andl(ToRegister(left), ToRegister(right));
          } else {
            __ andp(ToRegister(left), ToRegister(right));
          }
          break;
        case Token::BIT_OR:
          if (instr->IsInteger32()) {
            __ orl(ToRegister(left), ToRegister(right));
          } else {
            __ orp(ToRegister(left), ToRegister(right));
          }
          break;
        case Token::BIT_XOR:
          if (instr->IsInteger32()) {
            __ xorl(ToRegister(left), ToRegister(right));
          } else {
            __ xorp(ToRegister(left), ToRegister(right));
          }
          break;
        default:
          UNREACHABLE();
          break;
      }
    }
  }
  
  
  void LCodeGen::DoShiftI(LShiftI* instr) {
    LOperand* left = instr->left();
    LOperand* right = instr->right();
    DCHECK(left->Equals(instr->result()));
    DCHECK(left->IsRegister());
    if (right->IsRegister()) {
      DCHECK(ToRegister(right).is(rcx));
  
      switch (instr->op()) {
        case Token::ROR:
          __ rorl_cl(ToRegister(left));
          break;
        case Token::SAR:
          __ sarl_cl(ToRegister(left));
          break;
        case Token::SHR:
          __ shrl_cl(ToRegister(left));
          if (instr->can_deopt()) {
            __ testl(ToRegister(left), ToRegister(left));
            DeoptimizeIf(negative, instr, Deoptimizer::kNegativeValue);
          }
          break;
        case Token::SHL:
          __ shll_cl(ToRegister(left));
          break;
        default:
          UNREACHABLE();
          break;
      }
    } else {
      int32_t value = ToInteger32(LConstantOperand::cast(right));
      uint8_t shift_count = static_cast<uint8_t>(value & 0x1F);
      switch (instr->op()) {
        case Token::ROR:
          if (shift_count != 0) {
            __ rorl(ToRegister(left), Immediate(shift_count));
          }
          break;
        case Token::SAR:
          if (shift_count != 0) {
            __ sarl(ToRegister(left), Immediate(shift_count));
          }
          break;
        case Token::SHR:
          if (shift_count != 0) {
            __ shrl(ToRegister(left), Immediate(shift_count));
          } else if (instr->can_deopt()) {
            __ testl(ToRegister(left), ToRegister(left));
            DeoptimizeIf(negative, instr, Deoptimizer::kNegativeValue);
          }
          break;
        case Token::SHL:
          if (shift_count != 0) {
            if (instr->hydrogen_value()->representation().IsSmi()) {
              if (SmiValuesAre32Bits()) {
                __ shlp(ToRegister(left), Immediate(shift_count));
              } else {
                DCHECK(SmiValuesAre31Bits());
                if (instr->can_deopt()) {
                  if (shift_count != 1) {
                    __ shll(ToRegister(left), Immediate(shift_count - 1));
                  }
                  __ Integer32ToSmi(ToRegister(left), ToRegister(left));
                  DeoptimizeIf(overflow, instr, Deoptimizer::kOverflow);
                } else {
                  __ shll(ToRegister(left), Immediate(shift_count));
                }
              }
            } else {
              __ shll(ToRegister(left), Immediate(shift_count));
            }
          }
          break;
        default:
          UNREACHABLE();
          break;
      }
    }
  }
  
  
  void LCodeGen::DoSubI(LSubI* instr) {
    LOperand* left = instr->left();
    LOperand* right = instr->right();
    DCHECK(left->Equals(instr->result()));
  
    if (right->IsConstantOperand()) {
      int32_t right_operand =
          ToRepresentation(LConstantOperand::cast(right),
                           instr->hydrogen()->right()->representation());
      __ subl(ToRegister(left), Immediate(right_operand));
    } else if (right->IsRegister()) {
      if (instr->hydrogen_value()->representation().IsSmi()) {
        __ subp(ToRegister(left), ToRegister(right));
      } else {
        __ subl(ToRegister(left), ToRegister(right));
      }
    } else {
      if (instr->hydrogen_value()->representation().IsSmi()) {
        __ subp(ToRegister(left), ToOperand(right));
      } else {
        __ subl(ToRegister(left), ToOperand(right));
      }
    }
  
    if (instr->hydrogen()->CheckFlag(HValue::kCanOverflow)) {
      DeoptimizeIf(overflow, instr, Deoptimizer::kOverflow);
    }
  }
  
  
  void LCodeGen::DoConstantI(LConstantI* instr) {
    Register dst = ToRegister(instr->result());
    if (instr->value() == 0) {
      __ xorl(dst, dst);
    } else {
      __ movl(dst, Immediate(instr->value()));
    }
  }
  
  
  void LCodeGen::DoConstantS(LConstantS* instr) {
    __ Move(ToRegister(instr->result()), instr->value());
  }
  
  
  void LCodeGen::DoConstantD(LConstantD* instr) {
    __ Move(ToDoubleRegister(instr->result()), instr->bits());
  }
  
  
  void LCodeGen::DoConstantE(LConstantE* instr) {
    __ LoadAddress(ToRegister(instr->result()), instr->value());
  }
  
  
  void LCodeGen::DoConstantT(LConstantT* instr) {
    Handle<Object> object = instr->value(isolate());
    AllowDeferredHandleDereference smi_check;
    __ Move(ToRegister(instr->result()), object);
  }
  
  
  void LCodeGen::DoMapEnumLength(LMapEnumLength* instr) {
    Register result = ToRegister(instr->result());
    Register map = ToRegister(instr->value());
    __ EnumLength(result, map);
  }
  
  
  void LCodeGen::DoDateField(LDateField* instr) {
    Register object = ToRegister(instr->date());
    Register result = ToRegister(instr->result());
    Smi* index = instr->index();
    Label runtime, done, not_date_object;
    DCHECK(object.is(result));
    DCHECK(object.is(rax));
  
    Condition cc = masm()->CheckSmi(object);
    DeoptimizeIf(cc, instr, Deoptimizer::kSmi);
    __ CmpObjectType(object, JS_DATE_TYPE, kScratchRegister);
    DeoptimizeIf(not_equal, instr, Deoptimizer::kNotADateObject);
  
    if (index->value() == 0) {
      __ movp(result, FieldOperand(object, JSDate::kValueOffset));
    } else {
      if (index->value() < JSDate::kFirstUncachedField) {
        ExternalReference stamp = ExternalReference::date_cache_stamp(isolate());
        Operand stamp_operand = __ ExternalOperand(stamp);
        __ movp(kScratchRegister, stamp_operand);
        __ cmpp(kScratchRegister, FieldOperand(object,
                                               JSDate::kCacheStampOffset));
        __ j(not_equal, &runtime, Label::kNear);
        __ movp(result, FieldOperand(object, JSDate::kValueOffset +
                                             kPointerSize * index->value()));
        __ jmp(&done, Label::kNear);
      }
      __ bind(&runtime);
      __ PrepareCallCFunction(2);
      __ movp(arg_reg_1, object);
      __ Move(arg_reg_2, index, Assembler::RelocInfoNone());
      __ CallCFunction(ExternalReference::get_date_field_function(isolate()), 2);
      __ bind(&done);
    }
  }
  
  
  Operand LCodeGen::BuildSeqStringOperand(Register string,
                                          LOperand* index,
                                          String::Encoding encoding) {
    if (index->IsConstantOperand()) {
      int offset = ToInteger32(LConstantOperand::cast(index));
      if (encoding == String::TWO_BYTE_ENCODING) {
        offset *= kUC16Size;
      }
      STATIC_ASSERT(kCharSize == 1);
      return FieldOperand(string, SeqString::kHeaderSize + offset);
    }
    return FieldOperand(
        string, ToRegister(index),
        encoding == String::ONE_BYTE_ENCODING ? times_1 : times_2,
        SeqString::kHeaderSize);
  }
  
  
  void LCodeGen::DoSeqStringGetChar(LSeqStringGetChar* instr) {
    String::Encoding encoding = instr->hydrogen()->encoding();
    Register result = ToRegister(instr->result());
    Register string = ToRegister(instr->string());
  
    if (FLAG_debug_code) {
      __ Push(string);
      __ movp(string, FieldOperand(string, HeapObject::kMapOffset));
      __ movzxbp(string, FieldOperand(string, Map::kInstanceTypeOffset));
  
      __ andb(string, Immediate(kStringRepresentationMask | kStringEncodingMask));
      static const uint32_t one_byte_seq_type = kSeqStringTag | kOneByteStringTag;
      static const uint32_t two_byte_seq_type = kSeqStringTag | kTwoByteStringTag;
      __ cmpp(string, Immediate(encoding == String::ONE_BYTE_ENCODING
                                ? one_byte_seq_type : two_byte_seq_type));
      __ Check(equal, kUnexpectedStringType);
      __ Pop(string);
    }
  
    Operand operand = BuildSeqStringOperand(string, instr->index(), encoding);
    if (encoding == String::ONE_BYTE_ENCODING) {
      __ movzxbl(result, operand);
    } else {
      __ movzxwl(result, operand);
    }
  }
  
  
  void LCodeGen::DoSeqStringSetChar(LSeqStringSetChar* instr) {
    String::Encoding encoding = instr->hydrogen()->encoding();
    Register string = ToRegister(instr->string());
  
    if (FLAG_debug_code) {
      Register value = ToRegister(instr->value());
      Register index = ToRegister(instr->index());
      static const uint32_t one_byte_seq_type = kSeqStringTag | kOneByteStringTag;
      static const uint32_t two_byte_seq_type = kSeqStringTag | kTwoByteStringTag;
      int encoding_mask =
          instr->hydrogen()->encoding() == String::ONE_BYTE_ENCODING
          ? one_byte_seq_type : two_byte_seq_type;
      __ EmitSeqStringSetCharCheck(string, index, value, encoding_mask);
    }
  
    Operand operand = BuildSeqStringOperand(string, instr->index(), encoding);
    if (instr->value()->IsConstantOperand()) {
      int value = ToInteger32(LConstantOperand::cast(instr->value()));
      DCHECK_LE(0, value);
      if (encoding == String::ONE_BYTE_ENCODING) {
        DCHECK_LE(value, String::kMaxOneByteCharCode);
        __ movb(operand, Immediate(value));
      } else {
        DCHECK_LE(value, String::kMaxUtf16CodeUnit);
        __ movw(operand, Immediate(value));
      }
    } else {
      Register value = ToRegister(instr->value());
      if (encoding == String::ONE_BYTE_ENCODING) {
        __ movb(operand, value);
      } else {
        __ movw(operand, value);
      }
    }
  }
  
  
  void LCodeGen::DoAddI(LAddI* instr) {
    LOperand* left = instr->left();
    LOperand* right = instr->right();
  
    Representation target_rep = instr->hydrogen()->representation();
    bool is_p = target_rep.IsSmi() || target_rep.IsExternal();
  
    if (LAddI::UseLea(instr->hydrogen()) && !left->Equals(instr->result())) {
      if (right->IsConstantOperand()) {
        // No support for smi-immediates for 32-bit SMI.
        DCHECK(SmiValuesAre32Bits() ? !target_rep.IsSmi() : SmiValuesAre31Bits());
        int32_t offset =
            ToRepresentation(LConstantOperand::cast(right),
                             instr->hydrogen()->right()->representation());
        if (is_p) {
          __ leap(ToRegister(instr->result()),
                  MemOperand(ToRegister(left), offset));
        } else {
          __ leal(ToRegister(instr->result()),
                  MemOperand(ToRegister(left), offset));
        }
      } else {
        Operand address(ToRegister(left), ToRegister(right), times_1, 0);
        if (is_p) {
          __ leap(ToRegister(instr->result()), address);
        } else {
          __ leal(ToRegister(instr->result()), address);
        }
      }
    } else {
      if (right->IsConstantOperand()) {
        // No support for smi-immediates for 32-bit SMI.
        DCHECK(SmiValuesAre32Bits() ? !target_rep.IsSmi() : SmiValuesAre31Bits());
        int32_t right_operand =
            ToRepresentation(LConstantOperand::cast(right),
                             instr->hydrogen()->right()->representation());
        if (is_p) {
          __ addp(ToRegister(left), Immediate(right_operand));
        } else {
          __ addl(ToRegister(left), Immediate(right_operand));
        }
      } else if (right->IsRegister()) {
        if (is_p) {
          __ addp(ToRegister(left), ToRegister(right));
        } else {
          __ addl(ToRegister(left), ToRegister(right));
        }
      } else {
        if (is_p) {
          __ addp(ToRegister(left), ToOperand(right));
        } else {
          __ addl(ToRegister(left), ToOperand(right));
        }
      }
      if (instr->hydrogen()->CheckFlag(HValue::kCanOverflow)) {
        DeoptimizeIf(overflow, instr, Deoptimizer::kOverflow);
      }
    }
  }
  
  
  void LCodeGen::DoMathMinMax(LMathMinMax* instr) {
    LOperand* left = instr->left();
    LOperand* right = instr->right();
    DCHECK(left->Equals(instr->result()));
    HMathMinMax::Operation operation = instr->hydrogen()->operation();
    if (instr->hydrogen()->representation().IsSmiOrInteger32()) {
      Label return_left;
      Condition condition = (operation == HMathMinMax::kMathMin)
          ? less_equal
          : greater_equal;
      Register left_reg = ToRegister(left);
      if (right->IsConstantOperand()) {
        Immediate right_imm = Immediate(
            ToRepresentation(LConstantOperand::cast(right),
                             instr->hydrogen()->right()->representation()));
        DCHECK(SmiValuesAre32Bits()
            ? !instr->hydrogen()->representation().IsSmi()
            : SmiValuesAre31Bits());
        __ cmpl(left_reg, right_imm);
        __ j(condition, &return_left, Label::kNear);
        __ movp(left_reg, right_imm);
      } else if (right->IsRegister()) {
        Register right_reg = ToRegister(right);
        if (instr->hydrogen_value()->representation().IsSmi()) {
          __ cmpp(left_reg, right_reg);
        } else {
          __ cmpl(left_reg, right_reg);
        }
        __ j(condition, &return_left, Label::kNear);
        __ movp(left_reg, right_reg);
      } else {
        Operand right_op = ToOperand(right);
        if (instr->hydrogen_value()->representation().IsSmi()) {
          __ cmpp(left_reg, right_op);
        } else {
          __ cmpl(left_reg, right_op);
        }
        __ j(condition, &return_left, Label::kNear);
        __ movp(left_reg, right_op);
      }
      __ bind(&return_left);
    } else {
      DCHECK(instr->hydrogen()->representation().IsDouble());
      Label check_nan_left, check_zero, return_left, return_right;
      Condition condition = (operation == HMathMinMax::kMathMin) ? below : above;
      XMMRegister left_reg = ToDoubleRegister(left);
      XMMRegister right_reg = ToDoubleRegister(right);
      __ ucomisd(left_reg, right_reg);
      __ j(parity_even, &check_nan_left, Label::kNear);  // At least one NaN.
      __ j(equal, &check_zero, Label::kNear);  // left == right.
      __ j(condition, &return_left, Label::kNear);
      __ jmp(&return_right, Label::kNear);
  
      __ bind(&check_zero);
      XMMRegister xmm_scratch = double_scratch0();
      __ xorps(xmm_scratch, xmm_scratch);
      __ ucomisd(left_reg, xmm_scratch);
      __ j(not_equal, &return_left, Label::kNear);  // left == right != 0.
      // At this point, both left and right are either 0 or -0.
      if (operation == HMathMinMax::kMathMin) {
        __ orps(left_reg, right_reg);
      } else {
        // Since we operate on +0 and/or -0, addsd and andsd have the same effect.
        __ addsd(left_reg, right_reg);
      }
      __ jmp(&return_left, Label::kNear);
  
      __ bind(&check_nan_left);
      __ ucomisd(left_reg, left_reg);  // NaN check.
      __ j(parity_even, &return_left, Label::kNear);
      __ bind(&return_right);
      __ movaps(left_reg, right_reg);
  
      __ bind(&return_left);
    }
  }
  
  
  void LCodeGen::DoArithmeticD(LArithmeticD* instr) {
    XMMRegister left = ToDoubleRegister(instr->left());
    XMMRegister right = ToDoubleRegister(instr->right());
    XMMRegister result = ToDoubleRegister(instr->result());
    switch (instr->op()) {
      case Token::ADD:
        if (CpuFeatures::IsSupported(AVX)) {
          CpuFeatureScope scope(masm(), AVX);
          __ vaddsd(result, left, right);
        } else {
          DCHECK(result.is(left));
          __ addsd(left, right);
        }
        break;
      case Token::SUB:
        if (CpuFeatures::IsSupported(AVX)) {
          CpuFeatureScope scope(masm(), AVX);
          __ vsubsd(result, left, right);
        } else {
          DCHECK(result.is(left));
          __ subsd(left, right);
        }
         break;
      case Token::MUL:
        if (CpuFeatures::IsSupported(AVX)) {
          CpuFeatureScope scope(masm(), AVX);
          __ vmulsd(result, left, right);
        } else {
          DCHECK(result.is(left));
          __ mulsd(left, right);
        }
        break;
      case Token::DIV:
        if (CpuFeatures::IsSupported(AVX)) {
          CpuFeatureScope scope(masm(), AVX);
          __ vdivsd(result, left, right);
        } else {
          DCHECK(result.is(left));
          __ divsd(left, right);
        }
        // Don't delete this mov. It may improve performance on some CPUs,
        // when there is a (v)mulsd depending on the result
        __ movaps(result, result);
        break;
      case Token::MOD: {
        XMMRegister xmm_scratch = double_scratch0();
        __ PrepareCallCFunction(2);
        __ movaps(xmm_scratch, left);
        DCHECK(right.is(xmm1));
        __ CallCFunction(
            ExternalReference::mod_two_doubles_operation(isolate()), 2);
        __ movaps(result, xmm_scratch);
        break;
      }
      default:
        UNREACHABLE();
        break;
    }
  }
  
  
  void LCodeGen::DoArithmeticT(LArithmeticT* instr) {
    DCHECK(ToRegister(instr->context()).is(rsi));
    DCHECK(ToRegister(instr->left()).is(rdx));
    DCHECK(ToRegister(instr->right()).is(rax));
    DCHECK(ToRegister(instr->result()).is(rax));
  
    Handle<Code> code = CodeFactory::BinaryOpIC(
        isolate(), instr->op(), instr->language_mode()).code();
    CallCode(code, RelocInfo::CODE_TARGET, instr);
  }
  
  
  template<class InstrType>
  void LCodeGen::EmitBranch(InstrType instr, Condition cc) {
    int left_block = instr->TrueDestination(chunk_);
    int right_block = instr->FalseDestination(chunk_);
  
    int next_block = GetNextEmittedBlock();
  
    if (right_block == left_block || cc == no_condition) {
      EmitGoto(left_block);
    } else if (left_block == next_block) {
      __ j(NegateCondition(cc), chunk_->GetAssemblyLabel(right_block));
    } else if (right_block == next_block) {
      __ j(cc, chunk_->GetAssemblyLabel(left_block));
    } else {
      __ j(cc, chunk_->GetAssemblyLabel(left_block));
      if (cc != always) {
        __ jmp(chunk_->GetAssemblyLabel(right_block));
      }
    }
  }
  
  
  template<class InstrType>
  void LCodeGen::EmitFalseBranch(InstrType instr, Condition cc) {
    int false_block = instr->FalseDestination(chunk_);
    __ j(cc, chunk_->GetAssemblyLabel(false_block));
  }
  
  
  void LCodeGen::DoDebugBreak(LDebugBreak* instr) {
    __ int3();
  }
  
  
  void LCodeGen::DoBranch(LBranch* instr) {
    Representation r = instr->hydrogen()->value()->representation();
    if (r.IsInteger32()) {
      DCHECK(!info()->IsStub());
      Register reg = ToRegister(instr->value());
      __ testl(reg, reg);
      EmitBranch(instr, not_zero);
    } else if (r.IsSmi()) {
      DCHECK(!info()->IsStub());
      Register reg = ToRegister(instr->value());
      __ testp(reg, reg);
      EmitBranch(instr, not_zero);
    } else if (r.IsDouble()) {
      DCHECK(!info()->IsStub());
      XMMRegister reg = ToDoubleRegister(instr->value());
      XMMRegister xmm_scratch = double_scratch0();
      __ xorps(xmm_scratch, xmm_scratch);
      __ ucomisd(reg, xmm_scratch);
      EmitBranch(instr, not_equal);
    } else {
      DCHECK(r.IsTagged());
      Register reg = ToRegister(instr->value());
      HType type = instr->hydrogen()->value()->type();
      if (type.IsBoolean()) {
        DCHECK(!info()->IsStub());
        __ CompareRoot(reg, Heap::kTrueValueRootIndex);
        EmitBranch(instr, equal);
      } else if (type.IsSmi()) {
        DCHECK(!info()->IsStub());
        __ SmiCompare(reg, Smi::FromInt(0));
        EmitBranch(instr, not_equal);
      } else if (type.IsJSArray()) {
        DCHECK(!info()->IsStub());
        EmitBranch(instr, no_condition);
      } else if (type.IsHeapNumber()) {
        DCHECK(!info()->IsStub());
        XMMRegister xmm_scratch = double_scratch0();
        __ xorps(xmm_scratch, xmm_scratch);
        __ ucomisd(xmm_scratch, FieldOperand(reg, HeapNumber::kValueOffset));
        EmitBranch(instr, not_equal);
      } else if (type.IsString()) {
        DCHECK(!info()->IsStub());
        __ cmpp(FieldOperand(reg, String::kLengthOffset), Immediate(0));
        EmitBranch(instr, not_equal);
      } else {
        ToBooleanStub::Types expected = instr->hydrogen()->expected_input_types();
        // Avoid deopts in the case where we've never executed this path before.
        if (expected.IsEmpty()) expected = ToBooleanStub::Types::Generic();
  
        if (expected.Contains(ToBooleanStub::UNDEFINED)) {
          // undefined -> false.
          __ CompareRoot(reg, Heap::kUndefinedValueRootIndex);
          __ j(equal, instr->FalseLabel(chunk_));
        }
        if (expected.Contains(ToBooleanStub::BOOLEAN)) {
          // true -> true.
          __ CompareRoot(reg, Heap::kTrueValueRootIndex);
          __ j(equal, instr->TrueLabel(chunk_));
          // false -> false.
          __ CompareRoot(reg, Heap::kFalseValueRootIndex);
          __ j(equal, instr->FalseLabel(chunk_));
        }
        if (expected.Contains(ToBooleanStub::NULL_TYPE)) {
          // 'null' -> false.
          __ CompareRoot(reg, Heap::kNullValueRootIndex);
          __ j(equal, instr->FalseLabel(chunk_));
        }
  
        if (expected.Contains(ToBooleanStub::SMI)) {
          // Smis: 0 -> false, all other -> true.
          __ Cmp(reg, Smi::FromInt(0));
          __ j(equal, instr->FalseLabel(chunk_));
          __ JumpIfSmi(reg, instr->TrueLabel(chunk_));
        } else if (expected.NeedsMap()) {
          // If we need a map later and have a Smi -> deopt.
          __ testb(reg, Immediate(kSmiTagMask));
          DeoptimizeIf(zero, instr, Deoptimizer::kSmi);
        }
  
        const Register map = kScratchRegister;
        if (expected.NeedsMap()) {
          __ movp(map, FieldOperand(reg, HeapObject::kMapOffset));
  
          if (expected.CanBeUndetectable()) {
            // Undetectable -> false.
            __ testb(FieldOperand(map, Map::kBitFieldOffset),
                     Immediate(1 << Map::kIsUndetectable));
            __ j(not_zero, instr->FalseLabel(chunk_));
          }
        }
  
        if (expected.Contains(ToBooleanStub::SPEC_OBJECT)) {
          // spec object -> true.
          __ CmpInstanceType(map, FIRST_SPEC_OBJECT_TYPE);
          __ j(above_equal, instr->TrueLabel(chunk_));
        }
  
        if (expected.Contains(ToBooleanStub::STRING)) {
          // String value -> false iff empty.
          Label not_string;
          __ CmpInstanceType(map, FIRST_NONSTRING_TYPE);
          __ j(above_equal, &not_string, Label::kNear);
          __ cmpp(FieldOperand(reg, String::kLengthOffset), Immediate(0));
          __ j(not_zero, instr->TrueLabel(chunk_));
          __ jmp(instr->FalseLabel(chunk_));
          __ bind(&not_string);
        }
  
        if (expected.Contains(ToBooleanStub::SYMBOL)) {
          // Symbol value -> true.
          __ CmpInstanceType(map, SYMBOL_TYPE);
          __ j(equal, instr->TrueLabel(chunk_));
        }
  
        if (expected.Contains(ToBooleanStub::HEAP_NUMBER)) {
          // heap number -> false iff +0, -0, or NaN.
          Label not_heap_number;
          __ CompareRoot(map, Heap::kHeapNumberMapRootIndex);
          __ j(not_equal, &not_heap_number, Label::kNear);
          XMMRegister xmm_scratch = double_scratch0();
          __ xorps(xmm_scratch, xmm_scratch);
          __ ucomisd(xmm_scratch, FieldOperand(reg, HeapNumber::kValueOffset));
          __ j(zero, instr->FalseLabel(chunk_));
          __ jmp(instr->TrueLabel(chunk_));
          __ bind(&not_heap_number);
        }
  
        if (!expected.IsGeneric()) {
          // We've seen something for the first time -> deopt.
          // This can only happen if we are not generic already.
          DeoptimizeIf(no_condition, instr, Deoptimizer::kUnexpectedObject);
        }
      }
    }
  }
  
  
  void LCodeGen::EmitGoto(int block) {
    if (!IsNextEmittedBlock(block)) {
      __ jmp(chunk_->GetAssemblyLabel(chunk_->LookupDestination(block)));
    }
  }
  
  
  void LCodeGen::DoGoto(LGoto* instr) {
    EmitGoto(instr->block_id());
  }
  
  
  inline Condition LCodeGen::TokenToCondition(Token::Value op, bool is_unsigned) {
    Condition cond = no_condition;
    switch (op) {
      case Token::EQ:
      case Token::EQ_STRICT:
        cond = equal;
        break;
      case Token::NE:
      case Token::NE_STRICT:
        cond = not_equal;
        break;
      case Token::LT:
        cond = is_unsigned ? below : less;
        break;
      case Token::GT:
        cond = is_unsigned ? above : greater;
        break;
      case Token::LTE:
        cond = is_unsigned ? below_equal : less_equal;
        break;
      case Token::GTE:
        cond = is_unsigned ? above_equal : greater_equal;
        break;
      case Token::IN:
      case Token::INSTANCEOF:
      default:
        UNREACHABLE();
    }
    return cond;
  }
  
  
  void LCodeGen::DoCompareNumericAndBranch(LCompareNumericAndBranch* instr) {
    LOperand* left = instr->left();
    LOperand* right = instr->right();
    bool is_unsigned =
        instr->is_double() ||
        instr->hydrogen()->left()->CheckFlag(HInstruction::kUint32) ||
        instr->hydrogen()->right()->CheckFlag(HInstruction::kUint32);
    Condition cc = TokenToCondition(instr->op(), is_unsigned);
  
    if (left->IsConstantOperand() && right->IsConstantOperand()) {
      // We can statically evaluate the comparison.
      double left_val = ToDouble(LConstantOperand::cast(left));
      double right_val = ToDouble(LConstantOperand::cast(right));
      int next_block = EvalComparison(instr->op(), left_val, right_val) ?
          instr->TrueDestination(chunk_) : instr->FalseDestination(chunk_);
      EmitGoto(next_block);
    } else {
      if (instr->is_double()) {
        // Don't base result on EFLAGS when a NaN is involved. Instead
        // jump to the false block.
        __ ucomisd(ToDoubleRegister(left), ToDoubleRegister(right));
        __ j(parity_even, instr->FalseLabel(chunk_));
      } else {
        int32_t value;
        if (right->IsConstantOperand()) {
          value = ToInteger32(LConstantOperand::cast(right));
          if (instr->hydrogen_value()->representation().IsSmi()) {
            __ Cmp(ToRegister(left), Smi::FromInt(value));
          } else {
            __ cmpl(ToRegister(left), Immediate(value));
          }
        } else if (left->IsConstantOperand()) {
          value = ToInteger32(LConstantOperand::cast(left));
          if (instr->hydrogen_value()->representation().IsSmi()) {
            if (right->IsRegister()) {
              __ Cmp(ToRegister(right), Smi::FromInt(value));
            } else {
              __ Cmp(ToOperand(right), Smi::FromInt(value));
            }
          } else if (right->IsRegister()) {
            __ cmpl(ToRegister(right), Immediate(value));
          } else {
            __ cmpl(ToOperand(right), Immediate(value));
          }
          // We commuted the operands, so commute the condition.
          cc = CommuteCondition(cc);
        } else if (instr->hydrogen_value()->representation().IsSmi()) {
          if (right->IsRegister()) {
            __ cmpp(ToRegister(left), ToRegister(right));
          } else {
            __ cmpp(ToRegister(left), ToOperand(right));
          }
        } else {
          if (right->IsRegister()) {
            __ cmpl(ToRegister(left), ToRegister(right));
          } else {
            __ cmpl(ToRegister(left), ToOperand(right));
          }
        }
      }
      EmitBranch(instr, cc);
    }
  }
  
  
  void LCodeGen::DoCmpObjectEqAndBranch(LCmpObjectEqAndBranch* instr) {
    Register left = ToRegister(instr->left());
  
    if (instr->right()->IsConstantOperand()) {
      Handle<Object> right = ToHandle(LConstantOperand::cast(instr->right()));
      __ Cmp(left, right);
    } else {
      Register right = ToRegister(instr->right());
      __ cmpp(left, right);
    }
    EmitBranch(instr, equal);
  }
  
  
  void LCodeGen::DoCmpHoleAndBranch(LCmpHoleAndBranch* instr) {
    if (instr->hydrogen()->representation().IsTagged()) {
      Register input_reg = ToRegister(instr->object());
      __ Cmp(input_reg, factory()->the_hole_value());
      EmitBranch(instr, equal);
      return;
    }
  
    XMMRegister input_reg = ToDoubleRegister(instr->object());
    __ ucomisd(input_reg, input_reg);
    EmitFalseBranch(instr, parity_odd);
  
    __ subp(rsp, Immediate(kDoubleSize));
    __ movsd(MemOperand(rsp, 0), input_reg);
    __ addp(rsp, Immediate(kDoubleSize));
  
    int offset = sizeof(kHoleNanUpper32);
    __ cmpl(MemOperand(rsp, -offset), Immediate(kHoleNanUpper32));
    EmitBranch(instr, equal);
  }
  
  
  void LCodeGen::DoCompareMinusZeroAndBranch(LCompareMinusZeroAndBranch* instr) {
    Representation rep = instr->hydrogen()->value()->representation();
    DCHECK(!rep.IsInteger32());
  
    if (rep.IsDouble()) {
      XMMRegister value = ToDoubleRegister(instr->value());
      XMMRegister xmm_scratch = double_scratch0();
      __ xorps(xmm_scratch, xmm_scratch);
      __ ucomisd(xmm_scratch, value);
      EmitFalseBranch(instr, not_equal);
      __ movmskpd(kScratchRegister, value);
      __ testl(kScratchRegister, Immediate(1));
      EmitBranch(instr, not_zero);
    } else {
      Register value = ToRegister(instr->value());
      Handle<Map> map = masm()->isolate()->factory()->heap_number_map();
      __ CheckMap(value, map, instr->FalseLabel(chunk()), DO_SMI_CHECK);
      __ cmpl(FieldOperand(value, HeapNumber::kExponentOffset),
              Immediate(0x1));
      EmitFalseBranch(instr, no_overflow);
      __ cmpl(FieldOperand(value, HeapNumber::kMantissaOffset),
              Immediate(0x00000000));
      EmitBranch(instr, equal);
    }
  }
  
  
  Condition LCodeGen::EmitIsObject(Register input,
                                   Label* is_not_object,
                                   Label* is_object) {
    DCHECK(!input.is(kScratchRegister));
  
    __ JumpIfSmi(input, is_not_object);
  
    __ CompareRoot(input, Heap::kNullValueRootIndex);
    __ j(equal, is_object);
  
    __ movp(kScratchRegister, FieldOperand(input, HeapObject::kMapOffset));
    // Undetectable objects behave like undefined.
    __ testb(FieldOperand(kScratchRegister, Map::kBitFieldOffset),
             Immediate(1 << Map::kIsUndetectable));
    __ j(not_zero, is_not_object);
  
    __ movzxbl(kScratchRegister,
               FieldOperand(kScratchRegister, Map::kInstanceTypeOffset));
    __ cmpb(kScratchRegister, Immediate(FIRST_NONCALLABLE_SPEC_OBJECT_TYPE));
    __ j(below, is_not_object);
    __ cmpb(kScratchRegister, Immediate(LAST_NONCALLABLE_SPEC_OBJECT_TYPE));
    return below_equal;
  }
  
  
  void LCodeGen::DoIsObjectAndBranch(LIsObjectAndBranch* instr) {
    Register reg = ToRegister(instr->value());
  
    Condition true_cond = EmitIsObject(
        reg, instr->FalseLabel(chunk_), instr->TrueLabel(chunk_));
  
    EmitBranch(instr, true_cond);
  }
  
  
  Condition LCodeGen::EmitIsString(Register input,
                                   Register temp1,
                                   Label* is_not_string,
                                   SmiCheck check_needed = INLINE_SMI_CHECK) {
    if (check_needed == INLINE_SMI_CHECK) {
      __ JumpIfSmi(input, is_not_string);
    }
  
    Condition cond =  masm_->IsObjectStringType(input, temp1, temp1);
  
    return cond;
  }
  
  
  void LCodeGen::DoIsStringAndBranch(LIsStringAndBranch* instr) {
    Register reg = ToRegister(instr->value());
    Register temp = ToRegister(instr->temp());
  
    SmiCheck check_needed =
        instr->hydrogen()->value()->type().IsHeapObject()
            ? OMIT_SMI_CHECK : INLINE_SMI_CHECK;
  
    Condition true_cond = EmitIsString(
        reg, temp, instr->FalseLabel(chunk_), check_needed);
  
    EmitBranch(instr, true_cond);
  }
  
  
  void LCodeGen::DoIsSmiAndBranch(LIsSmiAndBranch* instr) {
    Condition is_smi;
    if (instr->value()->IsRegister()) {
      Register input = ToRegister(instr->value());
      is_smi = masm()->CheckSmi(input);
    } else {
      Operand input = ToOperand(instr->value());
      is_smi = masm()->CheckSmi(input);
    }
    EmitBranch(instr, is_smi);
  }
  
  
  void LCodeGen::DoIsUndetectableAndBranch(LIsUndetectableAndBranch* instr) {
    Register input = ToRegister(instr->value());
    Register temp = ToRegister(instr->temp());
  
    if (!instr->hydrogen()->value()->type().IsHeapObject()) {
      __ JumpIfSmi(input, instr->FalseLabel(chunk_));
    }
    __ movp(temp, FieldOperand(input, HeapObject::kMapOffset));
    __ testb(FieldOperand(temp, Map::kBitFieldOffset),
             Immediate(1 << Map::kIsUndetectable));
    EmitBranch(instr, not_zero);
  }
  
  
  void LCodeGen::DoStringCompareAndBranch(LStringCompareAndBranch* instr) {
    DCHECK(ToRegister(instr->context()).is(rsi));
    Token::Value op = instr->op();
  
    Handle<Code> ic = CodeFactory::CompareIC(isolate(), op, SLOPPY).code();
    CallCode(ic, RelocInfo::CODE_TARGET, instr);
  
    Condition condition = TokenToCondition(op, false);
    __ testp(rax, rax);
  
    EmitBranch(instr, condition);
  }
  
  
  static InstanceType TestType(HHasInstanceTypeAndBranch* instr) {
    InstanceType from = instr->from();
    InstanceType to = instr->to();
    if (from == FIRST_TYPE) return to;
    DCHECK(from == to || to == LAST_TYPE);
    return from;
  }
  
  
  static Condition BranchCondition(HHasInstanceTypeAndBranch* instr) {
    InstanceType from = instr->from();
    InstanceType to = instr->to();
    if (from == to) return equal;
    if (to == LAST_TYPE) return above_equal;
    if (from == FIRST_TYPE) return below_equal;
    UNREACHABLE();
    return equal;
  }
  
  
  void LCodeGen::DoHasInstanceTypeAndBranch(LHasInstanceTypeAndBranch* instr) {
    Register input = ToRegister(instr->value());
  
    if (!instr->hydrogen()->value()->type().IsHeapObject()) {
      __ JumpIfSmi(input, instr->FalseLabel(chunk_));
    }
  
    __ CmpObjectType(input, TestType(instr->hydrogen()), kScratchRegister);
    EmitBranch(instr, BranchCondition(instr->hydrogen()));
  }
  
  
  void LCodeGen::DoGetCachedArrayIndex(LGetCachedArrayIndex* instr) {
    Register input = ToRegister(instr->value());
    Register result = ToRegister(instr->result());
  
    __ AssertString(input);
  
    __ movl(result, FieldOperand(input, String::kHashFieldOffset));
    DCHECK(String::kHashShift >= kSmiTagSize);
    __ IndexFromHash(result, result);
  }
  
  
  void LCodeGen::DoHasCachedArrayIndexAndBranch(
      LHasCachedArrayIndexAndBranch* instr) {
    Register input = ToRegister(instr->value());
  
    __ testl(FieldOperand(input, String::kHashFieldOffset),
             Immediate(String::kContainsCachedArrayIndexMask));
    EmitBranch(instr, equal);
  }
  
  
  // Branches to a label or falls through with the answer in the z flag.
  // Trashes the temp register.
  void LCodeGen::EmitClassOfTest(Label* is_true,
                                 Label* is_false,
                                 Handle<String> class_name,
                                 Register input,
                                 Register temp,
                                 Register temp2) {
    DCHECK(!input.is(temp));
    DCHECK(!input.is(temp2));
    DCHECK(!temp.is(temp2));
  
    __ JumpIfSmi(input, is_false);
  
    if (String::Equals(isolate()->factory()->Function_string(), class_name)) {
      // Assuming the following assertions, we can use the same compares to test
      // for both being a function type and being in the object type range.
      STATIC_ASSERT(NUM_OF_CALLABLE_SPEC_OBJECT_TYPES == 2);
      STATIC_ASSERT(FIRST_NONCALLABLE_SPEC_OBJECT_TYPE ==
                    FIRST_SPEC_OBJECT_TYPE + 1);
      STATIC_ASSERT(LAST_NONCALLABLE_SPEC_OBJECT_TYPE ==
                    LAST_SPEC_OBJECT_TYPE - 1);
      STATIC_ASSERT(LAST_SPEC_OBJECT_TYPE == LAST_TYPE);
      __ CmpObjectType(input, FIRST_SPEC_OBJECT_TYPE, temp);
      __ j(below, is_false);
      __ j(equal, is_true);
      __ CmpInstanceType(temp, LAST_SPEC_OBJECT_TYPE);
      __ j(equal, is_true);
    } else {
      // Faster code path to avoid two compares: subtract lower bound from the
      // actual type and do a signed compare with the width of the type range.
      __ movp(temp, FieldOperand(input, HeapObject::kMapOffset));
      __ movzxbl(temp2, FieldOperand(temp, Map::kInstanceTypeOffset));
      __ subp(temp2, Immediate(FIRST_NONCALLABLE_SPEC_OBJECT_TYPE));
      __ cmpp(temp2, Immediate(LAST_NONCALLABLE_SPEC_OBJECT_TYPE -
                               FIRST_NONCALLABLE_SPEC_OBJECT_TYPE));
      __ j(above, is_false);
    }
  
    // Now we are in the FIRST-LAST_NONCALLABLE_SPEC_OBJECT_TYPE range.
    // Check if the constructor in the map is a function.
    __ GetMapConstructor(temp, temp, kScratchRegister);
  
    // Objects with a non-function constructor have class 'Object'.
    __ CmpInstanceType(kScratchRegister, JS_FUNCTION_TYPE);
    if (String::Equals(class_name, isolate()->factory()->Object_string())) {
      __ j(not_equal, is_true);
    } else {
      __ j(not_equal, is_false);
    }
  
    // temp now contains the constructor function. Grab the
    // instance class name from there.
    __ movp(temp, FieldOperand(temp, JSFunction::kSharedFunctionInfoOffset));
    __ movp(temp, FieldOperand(temp,
                               SharedFunctionInfo::kInstanceClassNameOffset));
    // The class name we are testing against is internalized since it's a literal.
    // The name in the constructor is internalized because of the way the context
    // is booted.  This routine isn't expected to work for random API-created
    // classes and it doesn't have to because you can't access it with natives
    // syntax.  Since both sides are internalized it is sufficient to use an
    // identity comparison.
    DCHECK(class_name->IsInternalizedString());
    __ Cmp(temp, class_name);
    // End with the answer in the z flag.
  }
  
  
  void LCodeGen::DoClassOfTestAndBranch(LClassOfTestAndBranch* instr) {
    Register input = ToRegister(instr->value());
    Register temp = ToRegister(instr->temp());
    Register temp2 = ToRegister(instr->temp2());
    Handle<String> class_name = instr->hydrogen()->class_name();
  
    EmitClassOfTest(instr->TrueLabel(chunk_), instr->FalseLabel(chunk_),
        class_name, input, temp, temp2);
  
    EmitBranch(instr, equal);
  }
  
  
  void LCodeGen::DoCmpMapAndBranch(LCmpMapAndBranch* instr) {
    Register reg = ToRegister(instr->value());
  
    __ Cmp(FieldOperand(reg, HeapObject::kMapOffset), instr->map());
    EmitBranch(instr, equal);
  }
  
  
  void LCodeGen::DoInstanceOf(LInstanceOf* instr) {
    DCHECK(ToRegister(instr->context()).is(rsi));
    InstanceofStub stub(isolate(), InstanceofStub::kNoFlags);
    __ Push(ToRegister(instr->left()));
    __ Push(ToRegister(instr->right()));
    CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
    Label true_value, done;
    __ testp(rax, rax);
    __ j(zero, &true_value, Label::kNear);
    __ LoadRoot(ToRegister(instr->result()), Heap::kFalseValueRootIndex);
    __ jmp(&done, Label::kNear);
    __ bind(&true_value);
    __ LoadRoot(ToRegister(instr->result()), Heap::kTrueValueRootIndex);
    __ bind(&done);
  }
  
  
  void LCodeGen::DoInstanceOfKnownGlobal(LInstanceOfKnownGlobal* instr) {
    class DeferredInstanceOfKnownGlobal final : public LDeferredCode {
     public:
      DeferredInstanceOfKnownGlobal(LCodeGen* codegen,
                                    LInstanceOfKnownGlobal* instr)
          : LDeferredCode(codegen), instr_(instr) { }
      void Generate() override {
        codegen()->DoDeferredInstanceOfKnownGlobal(instr_, &map_check_);
      }
      LInstruction* instr() override { return instr_; }
      Label* map_check() { return &map_check_; }
     private:
      LInstanceOfKnownGlobal* instr_;
      Label map_check_;
    };
  
    DCHECK(ToRegister(instr->context()).is(rsi));
    DeferredInstanceOfKnownGlobal* deferred;
    deferred = new(zone()) DeferredInstanceOfKnownGlobal(this, instr);
  
    Label done, false_result;
    Register object = ToRegister(instr->value());
  
    // A Smi is not an instance of anything.
    __ JumpIfSmi(object, &false_result, Label::kNear);
  
    // This is the inlined call site instanceof cache. The two occurences of the
    // hole value will be patched to the last map/result pair generated by the
    // instanceof stub.
    Label cache_miss;
    // Use a temp register to avoid memory operands with variable lengths.
    Register map = ToRegister(instr->temp());
    __ movp(map, FieldOperand(object, HeapObject::kMapOffset));
    __ bind(deferred->map_check());  // Label for calculating code patching.
    Handle<Cell> cache_cell = factory()->NewCell(factory()->the_hole_value());
    __ Move(kScratchRegister, cache_cell, RelocInfo::CELL);
    __ cmpp(map, Operand(kScratchRegister, 0));
    __ j(not_equal, &cache_miss, Label::kNear);
    // Patched to load either true or false.
    __ LoadRoot(ToRegister(instr->result()), Heap::kTheHoleValueRootIndex);
  #ifdef DEBUG
    // Check that the code size between patch label and patch sites is invariant.
    Label end_of_patched_code;
    __ bind(&end_of_patched_code);
    DCHECK(true);
  #endif
    __ jmp(&done, Label::kNear);
  
    // The inlined call site cache did not match. Check for null and string
    // before calling the deferred code.
    __ bind(&cache_miss);  // Null is not an instance of anything.
    __ CompareRoot(object, Heap::kNullValueRootIndex);
    __ j(equal, &false_result, Label::kNear);
  
    // String values are not instances of anything.
    __ JumpIfNotString(object, kScratchRegister, deferred->entry());
  
    __ bind(&false_result);
    __ LoadRoot(ToRegister(instr->result()), Heap::kFalseValueRootIndex);
  
    __ bind(deferred->exit());
    __ bind(&done);
  }
  
  
  void LCodeGen::DoDeferredInstanceOfKnownGlobal(LInstanceOfKnownGlobal* instr,
                                                 Label* map_check) {
    {
      PushSafepointRegistersScope scope(this);
      InstanceofStub::Flags flags = static_cast<InstanceofStub::Flags>(
          InstanceofStub::kNoFlags | InstanceofStub::kCallSiteInlineCheck);
      InstanceofStub stub(isolate(), flags);
  
      __ Push(ToRegister(instr->value()));
      __ Push(instr->function());
  
      static const int kAdditionalDelta = kPointerSize == kInt64Size ? 10 : 16;
      int delta =
          masm_->SizeOfCodeGeneratedSince(map_check) + kAdditionalDelta;
      DCHECK(delta >= 0);
      __ PushImm32(delta);
  
      // We are pushing three values on the stack but recording a
      // safepoint with two arguments because stub is going to
      // remove the third argument from the stack before jumping
      // to instanceof builtin on the slow path.
      CallCodeGeneric(stub.GetCode(),
                      RelocInfo::CODE_TARGET,
                      instr,
                      RECORD_SAFEPOINT_WITH_REGISTERS,
                      2);
      DCHECK(delta == masm_->SizeOfCodeGeneratedSince(map_check));
      LEnvironment* env = instr->GetDeferredLazyDeoptimizationEnvironment();
      safepoints_.RecordLazyDeoptimizationIndex(env->deoptimization_index());
      // Move result to a register that survives the end of the
      // PushSafepointRegisterScope.
      __ movp(kScratchRegister, rax);
    }
    __ testp(kScratchRegister, kScratchRegister);
    Label load_false;
    Label done;
    __ j(not_zero, &load_false, Label::kNear);
    __ LoadRoot(rax, Heap::kTrueValueRootIndex);
    __ jmp(&done, Label::kNear);
    __ bind(&load_false);
    __ LoadRoot(rax, Heap::kFalseValueRootIndex);
    __ bind(&done);
  }
  
  
  void LCodeGen::DoCmpT(LCmpT* instr) {
    DCHECK(ToRegister(instr->context()).is(rsi));
    Token::Value op = instr->op();
  
    Handle<Code> ic =
        CodeFactory::CompareIC(isolate(), op, instr->language_mode()).code();
    CallCode(ic, RelocInfo::CODE_TARGET, instr);
  
    Condition condition = TokenToCondition(op, false);
    Label true_value, done;
    __ testp(rax, rax);
    __ j(condition, &true_value, Label::kNear);
    __ LoadRoot(ToRegister(instr->result()), Heap::kFalseValueRootIndex);
    __ jmp(&done, Label::kNear);
    __ bind(&true_value);
    __ LoadRoot(ToRegister(instr->result()), Heap::kTrueValueRootIndex);
    __ bind(&done);
  }
  
  
  void LCodeGen::DoReturn(LReturn* instr) {
    if (FLAG_trace && info()->IsOptimizing()) {
      // Preserve the return value on the stack and rely on the runtime call
      // to return the value in the same register.  We're leaving the code
      // managed by the register allocator and tearing down the frame, it's
      // safe to write to the context register.
      __ Push(rax);
      __ movp(rsi, Operand(rbp, StandardFrameConstants::kContextOffset));
      __ CallRuntime(Runtime::kTraceExit, 1);
    }
    if (info()->saves_caller_doubles()) {
      RestoreCallerDoubles();
    }
    int no_frame_start = -1;
    if (NeedsEagerFrame()) {
      __ movp(rsp, rbp);
      __ popq(rbp);
      no_frame_start = masm_->pc_offset();
    }
    if (instr->has_constant_parameter_count()) {
      __ Ret((ToInteger32(instr->constant_parameter_count()) + 1) * kPointerSize,
             rcx);
    } else {
      DCHECK(info()->IsStub());  // Functions would need to drop one more value.
      Register reg = ToRegister(instr->parameter_count());
      // The argument count parameter is a smi
      __ SmiToInteger32(reg, reg);
      Register return_addr_reg = reg.is(rcx) ? rbx : rcx;
      __ PopReturnAddressTo(return_addr_reg);
      __ shlp(reg, Immediate(kPointerSizeLog2));
      __ addp(rsp, reg);
      __ jmp(return_addr_reg);
    }
    if (no_frame_start != -1) {
      info_->AddNoFrameRange(no_frame_start, masm_->pc_offset());
    }
  }
  
  
  template <class T>
  void LCodeGen::EmitVectorLoadICRegisters(T* instr) {
    Register vector_register = ToRegister(instr->temp_vector());
    Register slot_register = VectorLoadICDescriptor::SlotRegister();
    DCHECK(vector_register.is(VectorLoadICDescriptor::VectorRegister()));
    DCHECK(slot_register.is(rax));
  
    AllowDeferredHandleDereference vector_structure_check;
    Handle<TypeFeedbackVector> vector = instr->hydrogen()->feedback_vector();
    __ Move(vector_register, vector);
    // No need to allocate this register.
    FeedbackVectorICSlot slot = instr->hydrogen()->slot();
    int index = vector->GetIndex(slot);
    __ Move(slot_register, Smi::FromInt(index));
  }
  
  
  void LCodeGen::DoLoadGlobalGeneric(LLoadGlobalGeneric* instr) {
    DCHECK(ToRegister(instr->context()).is(rsi));
    DCHECK(ToRegister(instr->global_object())
               .is(LoadDescriptor::ReceiverRegister()));
    DCHECK(ToRegister(instr->result()).is(rax));
  
    __ Move(LoadDescriptor::NameRegister(), instr->name());
    EmitVectorLoadICRegisters<LLoadGlobalGeneric>(instr);
    ContextualMode mode = instr->for_typeof() ? NOT_CONTEXTUAL : CONTEXTUAL;
    Handle<Code> ic = CodeFactory::LoadICInOptimizedCode(isolate(), mode,
                                                         PREMONOMORPHIC).code();
    CallCode(ic, RelocInfo::CODE_TARGET, instr);
  }
  
  
  void LCodeGen::DoLoadContextSlot(LLoadContextSlot* instr) {
    Register context = ToRegister(instr->context());
    Register result = ToRegister(instr->result());
    __ movp(result, ContextOperand(context, instr->slot_index()));
    if (instr->hydrogen()->RequiresHoleCheck()) {
      __ CompareRoot(result, Heap::kTheHoleValueRootIndex);
      if (instr->hydrogen()->DeoptimizesOnHole()) {
        DeoptimizeIf(equal, instr, Deoptimizer::kHole);
      } else {
        Label is_not_hole;
        __ j(not_equal, &is_not_hole, Label::kNear);
        __ LoadRoot(result, Heap::kUndefinedValueRootIndex);
        __ bind(&is_not_hole);
      }
    }
  }
  
  
  void LCodeGen::DoStoreContextSlot(LStoreContextSlot* instr) {
    Register context = ToRegister(instr->context());
    Register value = ToRegister(instr->value());
  
    Operand target = ContextOperand(context, instr->slot_index());
  
    Label skip_assignment;
    if (instr->hydrogen()->RequiresHoleCheck()) {
      __ CompareRoot(target, Heap::kTheHoleValueRootIndex);
      if (instr->hydrogen()->DeoptimizesOnHole()) {
        DeoptimizeIf(equal, instr, Deoptimizer::kHole);
      } else {
        __ j(not_equal, &skip_assignment);
      }
    }
    __ movp(target, value);
  
    if (instr->hydrogen()->NeedsWriteBarrier()) {
      SmiCheck check_needed =
        instr->hydrogen()->value()->type().IsHeapObject()
            ? OMIT_SMI_CHECK : INLINE_SMI_CHECK;
      int offset = Context::SlotOffset(instr->slot_index());
      Register scratch = ToRegister(instr->temp());
      __ RecordWriteContextSlot(context,
                                offset,
                                value,
                                scratch,
                                kSaveFPRegs,
                                EMIT_REMEMBERED_SET,
                                check_needed);
    }
  
    __ bind(&skip_assignment);
  }
  
  
  void LCodeGen::DoLoadNamedField(LLoadNamedField* instr) {
    HObjectAccess access = instr->hydrogen()->access();
    int offset = access.offset();
  
    if (access.IsExternalMemory()) {
      Register result = ToRegister(instr->result());
      if (instr->object()->IsConstantOperand()) {
        DCHECK(result.is(rax));
        __ load_rax(ToExternalReference(LConstantOperand::cast(instr->object())));
      } else {
        Register object = ToRegister(instr->object());
        __ Load(result, MemOperand(object, offset), access.representation());
      }
      return;
    }
  
    Register object = ToRegister(instr->object());
    if (instr->hydrogen()->representation().IsDouble()) {
      DCHECK(access.IsInobject());
      XMMRegister result = ToDoubleRegister(instr->result());
      __ movsd(result, FieldOperand(object, offset));
      return;
    }
  
    Register result = ToRegister(instr->result());
    if (!access.IsInobject()) {
      __ movp(result, FieldOperand(object, JSObject::kPropertiesOffset));
      object = result;
    }
  
    Representation representation = access.representation();
    if (representation.IsSmi() && SmiValuesAre32Bits() &&
        instr->hydrogen()->representation().IsInteger32()) {
      if (FLAG_debug_code) {
        Register scratch = kScratchRegister;
        __ Load(scratch, FieldOperand(object, offset), representation);
        __ AssertSmi(scratch);
      }
  
      // Read int value directly from upper half of the smi.
      STATIC_ASSERT(kSmiTag == 0);
      DCHECK(kSmiTagSize + kSmiShiftSize == 32);
      offset += kPointerSize / 2;
      representation = Representation::Integer32();
    }
    __ Load(result, FieldOperand(object, offset), representation);
  }
  
  
  void LCodeGen::DoLoadNamedGeneric(LLoadNamedGeneric* instr) {
    DCHECK(ToRegister(instr->context()).is(rsi));
    DCHECK(ToRegister(instr->object()).is(LoadDescriptor::ReceiverRegister()));
    DCHECK(ToRegister(instr->result()).is(rax));
  
    __ Move(LoadDescriptor::NameRegister(), instr->name());
    EmitVectorLoadICRegisters<LLoadNamedGeneric>(instr);
    Handle<Code> ic = CodeFactory::LoadICInOptimizedCode(
                          isolate(), NOT_CONTEXTUAL,
                          instr->hydrogen()->initialization_state()).code();
    CallCode(ic, RelocInfo::CODE_TARGET, instr);
  }
  
  
  void LCodeGen::DoLoadFunctionPrototype(LLoadFunctionPrototype* instr) {
    Register function = ToRegister(instr->function());
    Register result = ToRegister(instr->result());
  
    // Get the prototype or initial map from the function.
    __ movp(result,
           FieldOperand(function, JSFunction::kPrototypeOrInitialMapOffset));
  
    // Check that the function has a prototype or an initial map.
    __ CompareRoot(result, Heap::kTheHoleValueRootIndex);
    DeoptimizeIf(equal, instr, Deoptimizer::kHole);
  
    // If the function does not have an initial map, we're done.
    Label done;
    __ CmpObjectType(result, MAP_TYPE, kScratchRegister);
    __ j(not_equal, &done, Label::kNear);
  
    // Get the prototype from the initial map.
    __ movp(result, FieldOperand(result, Map::kPrototypeOffset));
  
    // All done.
    __ bind(&done);
  }
  
  
  void LCodeGen::DoLoadRoot(LLoadRoot* instr) {
    Register result = ToRegister(instr->result());
    __ LoadRoot(result, instr->index());
  }
  
  
  void LCodeGen::DoAccessArgumentsAt(LAccessArgumentsAt* instr) {
    Register arguments = ToRegister(instr->arguments());
    Register result = ToRegister(instr->result());
  
    if (instr->length()->IsConstantOperand() &&
        instr->index()->IsConstantOperand()) {
      int32_t const_index = ToInteger32(LConstantOperand::cast(instr->index()));
      int32_t const_length = ToInteger32(LConstantOperand::cast(instr->length()));
      if (const_index >= 0 && const_index < const_length) {
        StackArgumentsAccessor args(arguments, const_length,
                                    ARGUMENTS_DONT_CONTAIN_RECEIVER);
        __ movp(result, args.GetArgumentOperand(const_index));
      } else if (FLAG_debug_code) {
        __ int3();
      }
    } else {
      Register length = ToRegister(instr->length());
      // There are two words between the frame pointer and the last argument.
      // Subtracting from length accounts for one of them add one more.
      if (instr->index()->IsRegister()) {
        __ subl(length, ToRegister(instr->index()));
      } else {
        __ subl(length, ToOperand(instr->index()));
      }
      StackArgumentsAccessor args(arguments, length,
                                  ARGUMENTS_DONT_CONTAIN_RECEIVER);
      __ movp(result, args.GetArgumentOperand(0));
    }
  }
  
  
  void LCodeGen::DoLoadKeyedExternalArray(LLoadKeyed* instr) {
    ElementsKind elements_kind = instr->elements_kind();
    LOperand* key = instr->key();
    if (kPointerSize == kInt32Size && !key->IsConstantOperand()) {
      Register key_reg = ToRegister(key);
      Representation key_representation =
          instr->hydrogen()->key()->representation();
      if (ExternalArrayOpRequiresTemp(key_representation, elements_kind)) {
        __ SmiToInteger64(key_reg, key_reg);
      } else if (instr->hydrogen()->IsDehoisted()) {
        // Sign extend key because it could be a 32 bit negative value
        // and the dehoisted address computation happens in 64 bits
        __ movsxlq(key_reg, key_reg);
      }
    }
    Operand operand(BuildFastArrayOperand(
        instr->elements(),
        key,
        instr->hydrogen()->key()->representation(),
        elements_kind,
        instr->base_offset()));
  
    if (elements_kind == EXTERNAL_FLOAT32_ELEMENTS ||
        elements_kind == FLOAT32_ELEMENTS) {
      XMMRegister result(ToDoubleRegister(instr->result()));
      __ movss(result, operand);
      __ cvtss2sd(result, result);
    } else if (elements_kind == EXTERNAL_FLOAT64_ELEMENTS ||
               elements_kind == FLOAT64_ELEMENTS) {
      __ movsd(ToDoubleRegister(instr->result()), operand);
    } else {
      Register result(ToRegister(instr->result()));
      switch (elements_kind) {
        case EXTERNAL_INT8_ELEMENTS:
        case INT8_ELEMENTS:
          __ movsxbl(result, operand);
          break;
        case EXTERNAL_UINT8_ELEMENTS:
        case EXTERNAL_UINT8_CLAMPED_ELEMENTS:
        case UINT8_ELEMENTS:
        case UINT8_CLAMPED_ELEMENTS:
          __ movzxbl(result, operand);
          break;
        case EXTERNAL_INT16_ELEMENTS:
        case INT16_ELEMENTS:
          __ movsxwl(result, operand);
          break;
        case EXTERNAL_UINT16_ELEMENTS:
        case UINT16_ELEMENTS:
          __ movzxwl(result, operand);
          break;
        case EXTERNAL_INT32_ELEMENTS:
        case INT32_ELEMENTS:
          __ movl(result, operand);
          break;
        case EXTERNAL_UINT32_ELEMENTS:
        case UINT32_ELEMENTS:
          __ movl(result, operand);
          if (!instr->hydrogen()->CheckFlag(HInstruction::kUint32)) {
            __ testl(result, result);
            DeoptimizeIf(negative, instr, Deoptimizer::kNegativeValue);
          }
          break;
        case EXTERNAL_FLOAT32_ELEMENTS:
        case EXTERNAL_FLOAT64_ELEMENTS:
        case FLOAT32_ELEMENTS:
        case FLOAT64_ELEMENTS:
        case FAST_ELEMENTS:
        case FAST_SMI_ELEMENTS:
        case FAST_DOUBLE_ELEMENTS:
        case FAST_HOLEY_ELEMENTS:
        case FAST_HOLEY_SMI_ELEMENTS:
        case FAST_HOLEY_DOUBLE_ELEMENTS:
        case DICTIONARY_ELEMENTS:
        case SLOPPY_ARGUMENTS_ELEMENTS:
          UNREACHABLE();
          break;
      }
    }
  }
  
  
  void LCodeGen::DoLoadKeyedFixedDoubleArray(LLoadKeyed* instr) {
    XMMRegister result(ToDoubleRegister(instr->result()));
    LOperand* key = instr->key();
    if (kPointerSize == kInt32Size && !key->IsConstantOperand() &&
        instr->hydrogen()->IsDehoisted()) {
      // Sign extend key because it could be a 32 bit negative value
      // and the dehoisted address computation happens in 64 bits
      __ movsxlq(ToRegister(key), ToRegister(key));
    }
    if (instr->hydrogen()->RequiresHoleCheck()) {
      Operand hole_check_operand = BuildFastArrayOperand(
          instr->elements(),
          key,
          instr->hydrogen()->key()->representation(),
          FAST_DOUBLE_ELEMENTS,
          instr->base_offset() + sizeof(kHoleNanLower32));
      __ cmpl(hole_check_operand, Immediate(kHoleNanUpper32));
      DeoptimizeIf(equal, instr, Deoptimizer::kHole);
    }
  
    Operand double_load_operand = BuildFastArrayOperand(
        instr->elements(),
        key,
        instr->hydrogen()->key()->representation(),
        FAST_DOUBLE_ELEMENTS,
        instr->base_offset());
    __ movsd(result, double_load_operand);
  }
  
  
  void LCodeGen::DoLoadKeyedFixedArray(LLoadKeyed* instr) {
    HLoadKeyed* hinstr = instr->hydrogen();
    Register result = ToRegister(instr->result());
    LOperand* key = instr->key();
    bool requires_hole_check = hinstr->RequiresHoleCheck();
    Representation representation = hinstr->representation();
    int offset = instr->base_offset();
  
    if (kPointerSize == kInt32Size && !key->IsConstantOperand() &&
        instr->hydrogen()->IsDehoisted()) {
      // Sign extend key because it could be a 32 bit negative value
      // and the dehoisted address computation happens in 64 bits
      __ movsxlq(ToRegister(key), ToRegister(key));
    }
    if (representation.IsInteger32() && SmiValuesAre32Bits() &&
        hinstr->elements_kind() == FAST_SMI_ELEMENTS) {
      DCHECK(!requires_hole_check);
      if (FLAG_debug_code) {
        Register scratch = kScratchRegister;
        __ Load(scratch,
                BuildFastArrayOperand(instr->elements(),
                                      key,
                                      instr->hydrogen()->key()->representation(),
                                      FAST_ELEMENTS,
                                      offset),
                Representation::Smi());
        __ AssertSmi(scratch);
      }
      // Read int value directly from upper half of the smi.
      STATIC_ASSERT(kSmiTag == 0);
      DCHECK(kSmiTagSize + kSmiShiftSize == 32);
      offset += kPointerSize / 2;
    }
  
    __ Load(result,
            BuildFastArrayOperand(instr->elements(), key,
                                  instr->hydrogen()->key()->representation(),
                                  FAST_ELEMENTS, offset),
            representation);
  
    // Check for the hole value.
    if (requires_hole_check) {
      if (IsFastSmiElementsKind(hinstr->elements_kind())) {
        Condition smi = __ CheckSmi(result);
        DeoptimizeIf(NegateCondition(smi), instr, Deoptimizer::kNotASmi);
      } else {
        __ CompareRoot(result, Heap::kTheHoleValueRootIndex);
        DeoptimizeIf(equal, instr, Deoptimizer::kHole);
      }
    } else if (hinstr->hole_mode() == CONVERT_HOLE_TO_UNDEFINED) {
      DCHECK(hinstr->elements_kind() == FAST_HOLEY_ELEMENTS);
      Label done;
      __ CompareRoot(result, Heap::kTheHoleValueRootIndex);
      __ j(not_equal, &done);
      if (info()->IsStub()) {
        // A stub can safely convert the hole to undefined only if the array
        // protector cell contains (Smi) Isolate::kArrayProtectorValid. Otherwise
        // it needs to bail out.
        __ LoadRoot(result, Heap::kArrayProtectorRootIndex);
        __ Cmp(FieldOperand(result, Cell::kValueOffset),
               Smi::FromInt(Isolate::kArrayProtectorValid));
        DeoptimizeIf(not_equal, instr, Deoptimizer::kHole);
      }
      __ Move(result, isolate()->factory()->undefined_value());
      __ bind(&done);
    }
  }
  
  
  void LCodeGen::DoLoadKeyed(LLoadKeyed* instr) {
    if (instr->is_typed_elements()) {
      DoLoadKeyedExternalArray(instr);
    } else if (instr->hydrogen()->representation().IsDouble()) {
      DoLoadKeyedFixedDoubleArray(instr);
    } else {
      DoLoadKeyedFixedArray(instr);
    }
  }
  
  
  Operand LCodeGen::BuildFastArrayOperand(
      LOperand* elements_pointer,
      LOperand* key,
      Representation key_representation,
      ElementsKind elements_kind,
      uint32_t offset) {
    Register elements_pointer_reg = ToRegister(elements_pointer);
    int shift_size = ElementsKindToShiftSize(elements_kind);
    if (key->IsConstantOperand()) {
      int32_t constant_value = ToInteger32(LConstantOperand::cast(key));
      if (constant_value & 0xF0000000) {
        Abort(kArrayIndexConstantValueTooBig);
      }
      return Operand(elements_pointer_reg,
                     (constant_value << shift_size) + offset);
    } else {
      // Guaranteed by ArrayInstructionInterface::KeyedAccessIndexRequirement().
      DCHECK(key_representation.IsInteger32());
  
      ScaleFactor scale_factor = static_cast<ScaleFactor>(shift_size);
      return Operand(elements_pointer_reg,
                     ToRegister(key),
                     scale_factor,
                     offset);
    }
  }
  
  
  void LCodeGen::DoLoadKeyedGeneric(LLoadKeyedGeneric* instr) {
    DCHECK(ToRegister(instr->context()).is(rsi));
    DCHECK(ToRegister(instr->object()).is(LoadDescriptor::ReceiverRegister()));
    DCHECK(ToRegister(instr->key()).is(LoadDescriptor::NameRegister()));
  
    if (instr->hydrogen()->HasVectorAndSlot()) {
      EmitVectorLoadICRegisters<LLoadKeyedGeneric>(instr);
    }
  
    Handle<Code> ic =
        CodeFactory::KeyedLoadICInOptimizedCode(
            isolate(), instr->hydrogen()->initialization_state()).code();
    CallCode(ic, RelocInfo::CODE_TARGET, instr);
  }
  
  
  void LCodeGen::DoArgumentsElements(LArgumentsElements* instr) {
    Register result = ToRegister(instr->result());
  
    if (instr->hydrogen()->from_inlined()) {
      __ leap(result, Operand(rsp, -kFPOnStackSize + -kPCOnStackSize));
    } else {
      // Check for arguments adapter frame.
      Label done, adapted;
      __ movp(result, Operand(rbp, StandardFrameConstants::kCallerFPOffset));
      __ Cmp(Operand(result, StandardFrameConstants::kContextOffset),
             Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR));
      __ j(equal, &adapted, Label::kNear);
  
      // No arguments adaptor frame.
      __ movp(result, rbp);
      __ jmp(&done, Label::kNear);
  
      // Arguments adaptor frame present.
      __ bind(&adapted);
      __ movp(result, Operand(rbp, StandardFrameConstants::kCallerFPOffset));
  
      // Result is the frame pointer for the frame if not adapted and for the real
      // frame below the adaptor frame if adapted.
      __ bind(&done);
    }
  }
  
  
  void LCodeGen::DoArgumentsLength(LArgumentsLength* instr) {
    Register result = ToRegister(instr->result());
  
    Label done;
  
    // If no arguments adaptor frame the number of arguments is fixed.
    if (instr->elements()->IsRegister()) {
      __ cmpp(rbp, ToRegister(instr->elements()));
    } else {
      __ cmpp(rbp, ToOperand(instr->elements()));
    }
    __ movl(result, Immediate(scope()->num_parameters()));
    __ j(equal, &done, Label::kNear);
  
    // Arguments adaptor frame present. Get argument length from there.
    __ movp(result, Operand(rbp, StandardFrameConstants::kCallerFPOffset));
    __ SmiToInteger32(result,
                      Operand(result,
                              ArgumentsAdaptorFrameConstants::kLengthOffset));
  
    // Argument length is in result register.
    __ bind(&done);
  }
  
  
  void LCodeGen::DoWrapReceiver(LWrapReceiver* instr) {
    Register receiver = ToRegister(instr->receiver());
    Register function = ToRegister(instr->function());
  
    // If the receiver is null or undefined, we have to pass the global
    // object as a receiver to normal functions. Values have to be
    // passed unchanged to builtins and strict-mode functions.
    Label global_object, receiver_ok;
    Label::Distance dist = DeoptEveryNTimes() ? Label::kFar : Label::kNear;
  
    if (!instr->hydrogen()->known_function()) {
      // Do not transform the receiver to object for strict mode
      // functions.
      __ movp(kScratchRegister,
              FieldOperand(function, JSFunction::kSharedFunctionInfoOffset));
      __ testb(FieldOperand(kScratchRegister,
                            SharedFunctionInfo::kStrictModeByteOffset),
               Immediate(1 << SharedFunctionInfo::kStrictModeBitWithinByte));
      __ j(not_equal, &receiver_ok, dist);
  
      // Do not transform the receiver to object for builtins.
      __ testb(FieldOperand(kScratchRegister,
                            SharedFunctionInfo::kNativeByteOffset),
               Immediate(1 << SharedFunctionInfo::kNativeBitWithinByte));
      __ j(not_equal, &receiver_ok, dist);
    }
  
    // Normal function. Replace undefined or null with global receiver.
    __ CompareRoot(receiver, Heap::kNullValueRootIndex);
    __ j(equal, &global_object, Label::kNear);
    __ CompareRoot(receiver, Heap::kUndefinedValueRootIndex);
    __ j(equal, &global_object, Label::kNear);
  
    // The receiver should be a JS object.
    Condition is_smi = __ CheckSmi(receiver);
    DeoptimizeIf(is_smi, instr, Deoptimizer::kSmi);
    __ CmpObjectType(receiver, FIRST_SPEC_OBJECT_TYPE, kScratchRegister);
    DeoptimizeIf(below, instr, Deoptimizer::kNotAJavaScriptObject);
  
    __ jmp(&receiver_ok, Label::kNear);
    __ bind(&global_object);
    __ movp(receiver, FieldOperand(function, JSFunction::kContextOffset));
    __ movp(receiver,
            Operand(receiver,
                    Context::SlotOffset(Context::GLOBAL_OBJECT_INDEX)));
    __ movp(receiver, FieldOperand(receiver, GlobalObject::kGlobalProxyOffset));
  
    __ bind(&receiver_ok);
  }
  
  
  void LCodeGen::DoApplyArguments(LApplyArguments* instr) {
    Register receiver = ToRegister(instr->receiver());
    Register function = ToRegister(instr->function());
    Register length = ToRegister(instr->length());
    Register elements = ToRegister(instr->elements());
    DCHECK(receiver.is(rax));  // Used for parameter count.
    DCHECK(function.is(rdi));  // Required by InvokeFunction.
    DCHECK(ToRegister(instr->result()).is(rax));
  
    // Copy the arguments to this function possibly from the
    // adaptor frame below it.
    const uint32_t kArgumentsLimit = 1 * KB;
    __ cmpp(length, Immediate(kArgumentsLimit));
    DeoptimizeIf(above, instr, Deoptimizer::kTooManyArguments);
  
    __ Push(receiver);
    __ movp(receiver, length);
  
    // Loop through the arguments pushing them onto the execution
    // stack.
    Label invoke, loop;
    // length is a small non-negative integer, due to the test above.
    __ testl(length, length);
    __ j(zero, &invoke, Label::kNear);
    __ bind(&loop);
    StackArgumentsAccessor args(elements, length,
                                ARGUMENTS_DONT_CONTAIN_RECEIVER);
    __ Push(args.GetArgumentOperand(0));
    __ decl(length);
    __ j(not_zero, &loop);
  
    // Invoke the function.
    __ bind(&invoke);
    DCHECK(instr->HasPointerMap());
    LPointerMap* pointers = instr->pointer_map();
    SafepointGenerator safepoint_generator(
        this, pointers, Safepoint::kLazyDeopt);
    ParameterCount actual(rax);
    __ InvokeFunction(function, actual, CALL_FUNCTION, safepoint_generator);
  }
  
  
  void LCodeGen::DoPushArgument(LPushArgument* instr) {
    LOperand* argument = instr->value();
    EmitPushTaggedOperand(argument);
  }
  
  
  void LCodeGen::DoDrop(LDrop* instr) {
    __ Drop(instr->count());
  }
  
  
  void LCodeGen::DoThisFunction(LThisFunction* instr) {
    Register result = ToRegister(instr->result());
    __ movp(result, Operand(rbp, JavaScriptFrameConstants::kFunctionOffset));
  }
  
  
  void LCodeGen::DoContext(LContext* instr) {
    Register result = ToRegister(instr->result());
    if (info()->IsOptimizing()) {
      __ movp(result, Operand(rbp, StandardFrameConstants::kContextOffset));
    } else {
      // If there is no frame, the context must be in rsi.
      DCHECK(result.is(rsi));
    }
  }
  
  
  void LCodeGen::DoDeclareGlobals(LDeclareGlobals* instr) {
    DCHECK(ToRegister(instr->context()).is(rsi));
    __ Push(rsi);  // The context is the first argument.
    __ Push(instr->hydrogen()->pairs());
    __ Push(Smi::FromInt(instr->hydrogen()->flags()));
    CallRuntime(Runtime::kDeclareGlobals, 3, instr);
  }
  
  
  void LCodeGen::CallKnownFunction(Handle<JSFunction> function,
                                   int formal_parameter_count, int arity,
                                   LInstruction* instr) {
    bool dont_adapt_arguments =
        formal_parameter_count == SharedFunctionInfo::kDontAdaptArgumentsSentinel;
    bool can_invoke_directly =
        dont_adapt_arguments || formal_parameter_count == arity;
  
    Register function_reg = rdi;
    LPointerMap* pointers = instr->pointer_map();
  
    if (can_invoke_directly) {
      // Change context.
      __ movp(rsi, FieldOperand(function_reg, JSFunction::kContextOffset));
  
      // Set rax to arguments count if adaption is not needed. Assumes that rax
      // is available to write to at this point.
      if (dont_adapt_arguments) {
        __ Set(rax, arity);
      }
  
      // Invoke function.
      if (function.is_identical_to(info()->closure())) {
        __ CallSelf();
      } else {
        __ Call(FieldOperand(function_reg, JSFunction::kCodeEntryOffset));
      }
  
      // Set up deoptimization.
      RecordSafepointWithLazyDeopt(instr, RECORD_SIMPLE_SAFEPOINT, 0);
    } else {
      // We need to adapt arguments.
      SafepointGenerator generator(
          this, pointers, Safepoint::kLazyDeopt);
      ParameterCount count(arity);
      ParameterCount expected(formal_parameter_count);
      __ InvokeFunction(function_reg, expected, count, CALL_FUNCTION, generator);
    }
  }
  
  
  void LCodeGen::DoCallWithDescriptor(LCallWithDescriptor* instr) {
    DCHECK(ToRegister(instr->result()).is(rax));
  
    if (instr->hydrogen()->IsTailCall()) {
      if (NeedsEagerFrame()) __ leave();
  
      if (instr->target()->IsConstantOperand()) {
        LConstantOperand* target = LConstantOperand::cast(instr->target());
        Handle<Code> code = Handle<Code>::cast(ToHandle(target));
        __ jmp(code, RelocInfo::CODE_TARGET);
      } else {
        DCHECK(instr->target()->IsRegister());
        Register target = ToRegister(instr->target());
        __ addp(target, Immediate(Code::kHeaderSize - kHeapObjectTag));
        __ jmp(target);
      }
    } else {
      LPointerMap* pointers = instr->pointer_map();
      SafepointGenerator generator(this, pointers, Safepoint::kLazyDeopt);
  
      if (instr->target()->IsConstantOperand()) {
        LConstantOperand* target = LConstantOperand::cast(instr->target());
        Handle<Code> code = Handle<Code>::cast(ToHandle(target));
        generator.BeforeCall(__ CallSize(code));
        __ call(code, RelocInfo::CODE_TARGET);
      } else {
        DCHECK(instr->target()->IsRegister());
        Register target = ToRegister(instr->target());
        generator.BeforeCall(__ CallSize(target));
        __ addp(target, Immediate(Code::kHeaderSize - kHeapObjectTag));
        __ call(target);
      }
      generator.AfterCall();
    }
  }
  
  
  void LCodeGen::DoCallJSFunction(LCallJSFunction* instr) {
    DCHECK(ToRegister(instr->function()).is(rdi));
    DCHECK(ToRegister(instr->result()).is(rax));
  
    if (instr->hydrogen()->pass_argument_count()) {
      __ Set(rax, instr->arity());
    }
  
    // Change context.
    __ movp(rsi, FieldOperand(rdi, JSFunction::kContextOffset));
  
    LPointerMap* pointers = instr->pointer_map();
    SafepointGenerator generator(this, pointers, Safepoint::kLazyDeopt);
  
    bool is_self_call = false;
    if (instr->hydrogen()->function()->IsConstant()) {
      Handle<JSFunction> jsfun = Handle<JSFunction>::null();
      HConstant* fun_const = HConstant::cast(instr->hydrogen()->function());
      jsfun = Handle<JSFunction>::cast(fun_const->handle(isolate()));
      is_self_call = jsfun.is_identical_to(info()->closure());
    }
  
    if (is_self_call) {
      __ CallSelf();
    } else {
      Operand target = FieldOperand(rdi, JSFunction::kCodeEntryOffset);
      generator.BeforeCall(__ CallSize(target));
      __ Call(target);
    }
    generator.AfterCall();
  }
  
  
  void LCodeGen::DoDeferredMathAbsTaggedHeapNumber(LMathAbs* instr) {
    Register input_reg = ToRegister(instr->value());
    __ CompareRoot(FieldOperand(input_reg, HeapObject::kMapOffset),
                   Heap::kHeapNumberMapRootIndex);
    DeoptimizeIf(not_equal, instr, Deoptimizer::kNotAHeapNumber);
  
    Label slow, allocated, done;
    Register tmp = input_reg.is(rax) ? rcx : rax;
    Register tmp2 = tmp.is(rcx) ? rdx : input_reg.is(rcx) ? rdx : rcx;
  
    // Preserve the value of all registers.
    PushSafepointRegistersScope scope(this);
  
    __ movl(tmp, FieldOperand(input_reg, HeapNumber::kExponentOffset));
    // Check the sign of the argument. If the argument is positive, just
    // return it. We do not need to patch the stack since |input| and
    // |result| are the same register and |input| will be restored
    // unchanged by popping safepoint registers.
    __ testl(tmp, Immediate(HeapNumber::kSignMask));
    __ j(zero, &done);
  
    __ AllocateHeapNumber(tmp, tmp2, &slow);
    __ jmp(&allocated, Label::kNear);
  
    // Slow case: Call the runtime system to do the number allocation.
    __ bind(&slow);
    CallRuntimeFromDeferred(
        Runtime::kAllocateHeapNumber, 0, instr, instr->context());
    // Set the pointer to the new heap number in tmp.
    if (!tmp.is(rax)) __ movp(tmp, rax);
    // Restore input_reg after call to runtime.
    __ LoadFromSafepointRegisterSlot(input_reg, input_reg);
  
    __ bind(&allocated);
    __ movq(tmp2, FieldOperand(input_reg, HeapNumber::kValueOffset));
    __ shlq(tmp2, Immediate(1));
    __ shrq(tmp2, Immediate(1));
    __ movq(FieldOperand(tmp, HeapNumber::kValueOffset), tmp2);
    __ StoreToSafepointRegisterSlot(input_reg, tmp);
  
    __ bind(&done);
  }
  
  
  void LCodeGen::EmitIntegerMathAbs(LMathAbs* instr) {
    Register input_reg = ToRegister(instr->value());
    __ testl(input_reg, input_reg);
    Label is_positive;
    __ j(not_sign, &is_positive, Label::kNear);
    __ negl(input_reg);  // Sets flags.
    DeoptimizeIf(negative, instr, Deoptimizer::kOverflow);
    __ bind(&is_positive);
  }
  
  
  void LCodeGen::EmitSmiMathAbs(LMathAbs* instr) {
    Register input_reg = ToRegister(instr->value());
    __ testp(input_reg, input_reg);
    Label is_positive;
    __ j(not_sign, &is_positive, Label::kNear);
    __ negp(input_reg);  // Sets flags.
    DeoptimizeIf(negative, instr, Deoptimizer::kOverflow);
    __ bind(&is_positive);
  }
  
  
  void LCodeGen::DoMathAbs(LMathAbs* instr) {
    // Class for deferred case.
    class DeferredMathAbsTaggedHeapNumber final : public LDeferredCode {
     public:
      DeferredMathAbsTaggedHeapNumber(LCodeGen* codegen, LMathAbs* instr)
          : LDeferredCode(codegen), instr_(instr) { }
      void Generate() override {
        codegen()->DoDeferredMathAbsTaggedHeapNumber(instr_);
      }
      LInstruction* instr() override { return instr_; }
  
     private:
      LMathAbs* instr_;
    };
  
    DCHECK(instr->value()->Equals(instr->result()));
    Representation r = instr->hydrogen()->value()->representation();
  
    if (r.IsDouble()) {
      XMMRegister scratch = double_scratch0();
      XMMRegister input_reg = ToDoubleRegister(instr->value());
      __ xorps(scratch, scratch);
      __ subsd(scratch, input_reg);
      __ andps(input_reg, scratch);
    } else if (r.IsInteger32()) {
      EmitIntegerMathAbs(instr);
    } else if (r.IsSmi()) {
      EmitSmiMathAbs(instr);
    } else {  // Tagged case.
      DeferredMathAbsTaggedHeapNumber* deferred =
          new(zone()) DeferredMathAbsTaggedHeapNumber(this, instr);
      Register input_reg = ToRegister(instr->value());
      // Smi check.
      __ JumpIfNotSmi(input_reg, deferred->entry());
      EmitSmiMathAbs(instr);
      __ bind(deferred->exit());
    }
  }
  
  
  void LCodeGen::DoMathFloor(LMathFloor* instr) {
    XMMRegister xmm_scratch = double_scratch0();
    Register output_reg = ToRegister(instr->result());
    XMMRegister input_reg = ToDoubleRegister(instr->value());
  
    if (CpuFeatures::IsSupported(SSE4_1)) {
      CpuFeatureScope scope(masm(), SSE4_1);
      if (instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero)) {
        // Deoptimize if minus zero.
        __ movq(output_reg, input_reg);
        __ subq(output_reg, Immediate(1));
        DeoptimizeIf(overflow, instr, Deoptimizer::kMinusZero);
      }
      __ roundsd(xmm_scratch, input_reg, kRoundDown);
      __ cvttsd2si(output_reg, xmm_scratch);
      __ cmpl(output_reg, Immediate(0x1));
      DeoptimizeIf(overflow, instr, Deoptimizer::kOverflow);
    } else {
      Label negative_sign, done;
      // Deoptimize on unordered.
      __ xorps(xmm_scratch, xmm_scratch);  // Zero the register.
      __ ucomisd(input_reg, xmm_scratch);
      DeoptimizeIf(parity_even, instr, Deoptimizer::kNaN);
      __ j(below, &negative_sign, Label::kNear);
  
      if (instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero)) {
        // Check for negative zero.
        Label positive_sign;
        __ j(above, &positive_sign, Label::kNear);
        __ movmskpd(output_reg, input_reg);
        __ testq(output_reg, Immediate(1));
        DeoptimizeIf(not_zero, instr, Deoptimizer::kMinusZero);
        __ Set(output_reg, 0);
        __ jmp(&done);
        __ bind(&positive_sign);
      }
  
      // Use truncating instruction (OK because input is positive).
      __ cvttsd2si(output_reg, input_reg);
      // Overflow is signalled with minint.
      __ cmpl(output_reg, Immediate(0x1));
      DeoptimizeIf(overflow, instr, Deoptimizer::kOverflow);
      __ jmp(&done, Label::kNear);
  
      // Non-zero negative reaches here.
      __ bind(&negative_sign);
      // Truncate, then compare and compensate.
      __ cvttsd2si(output_reg, input_reg);
      __ Cvtlsi2sd(xmm_scratch, output_reg);
      __ ucomisd(input_reg, xmm_scratch);
      __ j(equal, &done, Label::kNear);
      __ subl(output_reg, Immediate(1));
      DeoptimizeIf(overflow, instr, Deoptimizer::kOverflow);
  
      __ bind(&done);
    }
  }
  
  
  void LCodeGen::DoMathRound(LMathRound* instr) {
    const XMMRegister xmm_scratch = double_scratch0();
    Register output_reg = ToRegister(instr->result());
    XMMRegister input_reg = ToDoubleRegister(instr->value());
    XMMRegister input_temp = ToDoubleRegister(instr->temp());
    static int64_t one_half = V8_INT64_C(0x3FE0000000000000);  // 0.5
    static int64_t minus_one_half = V8_INT64_C(0xBFE0000000000000);  // -0.5
  
    Label done, round_to_zero, below_one_half;
    Label::Distance dist = DeoptEveryNTimes() ? Label::kFar : Label::kNear;
    __ movq(kScratchRegister, one_half);
    __ movq(xmm_scratch, kScratchRegister);
    __ ucomisd(xmm_scratch, input_reg);
    __ j(above, &below_one_half, Label::kNear);
  
    // CVTTSD2SI rounds towards zero, since 0.5 <= x, we use floor(0.5 + x).
    __ addsd(xmm_scratch, input_reg);
    __ cvttsd2si(output_reg, xmm_scratch);
    // Overflow is signalled with minint.
    __ cmpl(output_reg, Immediate(0x1));
    DeoptimizeIf(overflow, instr, Deoptimizer::kOverflow);
    __ jmp(&done, dist);
  
    __ bind(&below_one_half);
    __ movq(kScratchRegister, minus_one_half);
    __ movq(xmm_scratch, kScratchRegister);
    __ ucomisd(xmm_scratch, input_reg);
    __ j(below_equal, &round_to_zero, Label::kNear);
  
    // CVTTSD2SI rounds towards zero, we use ceil(x - (-0.5)) and then
    // compare and compensate.
    __ movq(input_temp, input_reg);  // Do not alter input_reg.
    __ subsd(input_temp, xmm_scratch);
    __ cvttsd2si(output_reg, input_temp);
    // Catch minint due to overflow, and to prevent overflow when compensating.
    __ cmpl(output_reg, Immediate(0x1));
    DeoptimizeIf(overflow, instr, Deoptimizer::kOverflow);
  
    __ Cvtlsi2sd(xmm_scratch, output_reg);
    __ ucomisd(xmm_scratch, input_temp);
    __ j(equal, &done, dist);
    __ subl(output_reg, Immediate(1));
    // No overflow because we already ruled out minint.
    __ jmp(&done, dist);
  
    __ bind(&round_to_zero);
    // We return 0 for the input range [+0, 0.5[, or [-0.5, 0.5[ if
    // we can ignore the difference between a result of -0 and +0.
    if (instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero)) {
      __ movq(output_reg, input_reg);
      __ testq(output_reg, output_reg);
      DeoptimizeIf(negative, instr, Deoptimizer::kMinusZero);
    }
    __ Set(output_reg, 0);
    __ bind(&done);
  }
  
  
  void LCodeGen::DoMathFround(LMathFround* instr) {
    XMMRegister input_reg = ToDoubleRegister(instr->value());
    XMMRegister output_reg = ToDoubleRegister(instr->result());
    __ cvtsd2ss(output_reg, input_reg);
    __ cvtss2sd(output_reg, output_reg);
  }
  
  
  void LCodeGen::DoMathSqrt(LMathSqrt* instr) {
    XMMRegister output = ToDoubleRegister(instr->result());
    if (instr->value()->IsDoubleRegister()) {
      XMMRegister input = ToDoubleRegister(instr->value());
      __ sqrtsd(output, input);
    } else {
      Operand input = ToOperand(instr->value());
      __ sqrtsd(output, input);
    }
  }
  
  
  void LCodeGen::DoMathPowHalf(LMathPowHalf* instr) {
    XMMRegister xmm_scratch = double_scratch0();
    XMMRegister input_reg = ToDoubleRegister(instr->value());
    DCHECK(ToDoubleRegister(instr->result()).is(input_reg));
  
    // Note that according to ECMA-262 15.8.2.13:
    // Math.pow(-Infinity, 0.5) == Infinity
    // Math.sqrt(-Infinity) == NaN
    Label done, sqrt;
    // Check base for -Infinity.  According to IEEE-754, double-precision
    // -Infinity has the highest 12 bits set and the lowest 52 bits cleared.
    __ movq(kScratchRegister, V8_INT64_C(0xFFF0000000000000));
    __ movq(xmm_scratch, kScratchRegister);
    __ ucomisd(xmm_scratch, input_reg);
    // Comparing -Infinity with NaN results in "unordered", which sets the
    // zero flag as if both were equal.  However, it also sets the carry flag.
    __ j(not_equal, &sqrt, Label::kNear);
    __ j(carry, &sqrt, Label::kNear);
    // If input is -Infinity, return Infinity.
    __ xorps(input_reg, input_reg);
    __ subsd(input_reg, xmm_scratch);
    __ jmp(&done, Label::kNear);
  
    // Square root.
    __ bind(&sqrt);
    __ xorps(xmm_scratch, xmm_scratch);
    __ addsd(input_reg, xmm_scratch);  // Convert -0 to +0.
    __ sqrtsd(input_reg, input_reg);
    __ bind(&done);
  }
  
  
  void LCodeGen::DoPower(LPower* instr) {
    Representation exponent_type = instr->hydrogen()->right()->representation();
    // Having marked this as a call, we can use any registers.
    // Just make sure that the input/output registers are the expected ones.
  
    Register tagged_exponent = MathPowTaggedDescriptor::exponent();
    DCHECK(!instr->right()->IsRegister() ||
           ToRegister(instr->right()).is(tagged_exponent));
    DCHECK(!instr->right()->IsDoubleRegister() ||
           ToDoubleRegister(instr->right()).is(xmm1));
    DCHECK(ToDoubleRegister(instr->left()).is(xmm2));
    DCHECK(ToDoubleRegister(instr->result()).is(xmm3));
  
    if (exponent_type.IsSmi()) {
      MathPowStub stub(isolate(), MathPowStub::TAGGED);
      __ CallStub(&stub);
    } else if (exponent_type.IsTagged()) {
      Label no_deopt;
      __ JumpIfSmi(tagged_exponent, &no_deopt, Label::kNear);
      __ CmpObjectType(tagged_exponent, HEAP_NUMBER_TYPE, rcx);
      DeoptimizeIf(not_equal, instr, Deoptimizer::kNotAHeapNumber);
      __ bind(&no_deopt);
      MathPowStub stub(isolate(), MathPowStub::TAGGED);
      __ CallStub(&stub);
    } else if (exponent_type.IsInteger32()) {
      MathPowStub stub(isolate(), MathPowStub::INTEGER);
      __ CallStub(&stub);
    } else {
      DCHECK(exponent_type.IsDouble());
      MathPowStub stub(isolate(), MathPowStub::DOUBLE);
      __ CallStub(&stub);
    }
  }
  
  
  void LCodeGen::DoMathExp(LMathExp* instr) {
    XMMRegister input = ToDoubleRegister(instr->value());
    XMMRegister result = ToDoubleRegister(instr->result());
    XMMRegister temp0 = double_scratch0();
    Register temp1 = ToRegister(instr->temp1());
    Register temp2 = ToRegister(instr->temp2());
  
    MathExpGenerator::EmitMathExp(masm(), input, result, temp0, temp1, temp2);
  }
  
  
  void LCodeGen::DoMathLog(LMathLog* instr) {
    DCHECK(instr->value()->Equals(instr->result()));
    XMMRegister input_reg = ToDoubleRegister(instr->value());
    XMMRegister xmm_scratch = double_scratch0();
    Label positive, done, zero;
    __ xorps(xmm_scratch, xmm_scratch);
    __ ucomisd(input_reg, xmm_scratch);
    __ j(above, &positive, Label::kNear);
    __ j(not_carry, &zero, Label::kNear);
    __ pcmpeqd(input_reg, input_reg);
    __ jmp(&done, Label::kNear);
    __ bind(&zero);
    ExternalReference ninf =
        ExternalReference::address_of_negative_infinity();
    Operand ninf_operand = masm()->ExternalOperand(ninf);
    __ movsd(input_reg, ninf_operand);
    __ jmp(&done, Label::kNear);
    __ bind(&positive);
    __ fldln2();
    __ subp(rsp, Immediate(kDoubleSize));
    __ movsd(Operand(rsp, 0), input_reg);
    __ fld_d(Operand(rsp, 0));
    __ fyl2x();
    __ fstp_d(Operand(rsp, 0));
    __ movsd(input_reg, Operand(rsp, 0));
    __ addp(rsp, Immediate(kDoubleSize));
    __ bind(&done);
  }
  
  
  void LCodeGen::DoMathClz32(LMathClz32* instr) {
    Register input = ToRegister(instr->value());
    Register result = ToRegister(instr->result());
  
    __ Lzcntl(result, input);
  }
  
  
  void LCodeGen::DoInvokeFunction(LInvokeFunction* instr) {
    DCHECK(ToRegister(instr->context()).is(rsi));
    DCHECK(ToRegister(instr->function()).is(rdi));
    DCHECK(instr->HasPointerMap());
  
    Handle<JSFunction> known_function = instr->hydrogen()->known_function();
    if (known_function.is_null()) {
      LPointerMap* pointers = instr->pointer_map();
      SafepointGenerator generator(this, pointers, Safepoint::kLazyDeopt);
      ParameterCount count(instr->arity());
      __ InvokeFunction(rdi, count, CALL_FUNCTION, generator);
    } else {
      CallKnownFunction(known_function,
                        instr->hydrogen()->formal_parameter_count(),
                        instr->arity(), instr);
    }
  }
  
  
  void LCodeGen::DoCallFunction(LCallFunction* instr) {
    DCHECK(ToRegister(instr->context()).is(rsi));
    DCHECK(ToRegister(instr->function()).is(rdi));
    DCHECK(ToRegister(instr->result()).is(rax));
  
    int arity = instr->arity();
    CallFunctionFlags flags = instr->hydrogen()->function_flags();
    if (instr->hydrogen()->HasVectorAndSlot()) {
      Register slot_register = ToRegister(instr->temp_slot());
      Register vector_register = ToRegister(instr->temp_vector());
      DCHECK(slot_register.is(rdx));
      DCHECK(vector_register.is(rbx));
  
      AllowDeferredHandleDereference vector_structure_check;
      Handle<TypeFeedbackVector> vector = instr->hydrogen()->feedback_vector();
      int index = vector->GetIndex(instr->hydrogen()->slot());
  
      __ Move(vector_register, vector);
      __ Move(slot_register, Smi::FromInt(index));
  
      CallICState::CallType call_type =
          (flags & CALL_AS_METHOD) ? CallICState::METHOD : CallICState::FUNCTION;
  
      Handle<Code> ic =
          CodeFactory::CallICInOptimizedCode(isolate(), arity, call_type).code();
      CallCode(ic, RelocInfo::CODE_TARGET, instr);
    } else {
      CallFunctionStub stub(isolate(), arity, flags);
      CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
    }
  }
  
  
  void LCodeGen::DoCallNew(LCallNew* instr) {
    DCHECK(ToRegister(instr->context()).is(rsi));
    DCHECK(ToRegister(instr->constructor()).is(rdi));
    DCHECK(ToRegister(instr->result()).is(rax));
  
    __ Set(rax, instr->arity());
    // No cell in ebx for construct type feedback in optimized code
    __ LoadRoot(rbx, Heap::kUndefinedValueRootIndex);
    CallConstructStub stub(isolate(), NO_CALL_CONSTRUCTOR_FLAGS);
    CallCode(stub.GetCode(), RelocInfo::CONSTRUCT_CALL, instr);
  }
  
  
  void LCodeGen::DoCallNewArray(LCallNewArray* instr) {
    DCHECK(ToRegister(instr->context()).is(rsi));
    DCHECK(ToRegister(instr->constructor()).is(rdi));
    DCHECK(ToRegister(instr->result()).is(rax));
  
    __ Set(rax, instr->arity());
    if (instr->arity() == 1) {
      // We only need the allocation site for the case we have a length argument.
      // The case may bail out to the runtime, which will determine the correct
      // elements kind with the site.
      __ Move(rbx, instr->hydrogen()->site());
    } else {
      __ LoadRoot(rbx, Heap::kUndefinedValueRootIndex);
    }
  
    ElementsKind kind = instr->hydrogen()->elements_kind();
    AllocationSiteOverrideMode override_mode =
        (AllocationSite::GetMode(kind) == TRACK_ALLOCATION_SITE)
            ? DISABLE_ALLOCATION_SITES
            : DONT_OVERRIDE;
  
    if (instr->arity() == 0) {
      ArrayNoArgumentConstructorStub stub(isolate(), kind, override_mode);
      CallCode(stub.GetCode(), RelocInfo::CONSTRUCT_CALL, instr);
    } else if (instr->arity() == 1) {
      Label done;
      if (IsFastPackedElementsKind(kind)) {
        Label packed_case;
        // We might need a change here
        // look at the first argument
        __ movp(rcx, Operand(rsp, 0));
        __ testp(rcx, rcx);
        __ j(zero, &packed_case, Label::kNear);
  
        ElementsKind holey_kind = GetHoleyElementsKind(kind);
        ArraySingleArgumentConstructorStub stub(isolate(),
                                                holey_kind,
                                                override_mode);
        CallCode(stub.GetCode(), RelocInfo::CONSTRUCT_CALL, instr);
        __ jmp(&done, Label::kNear);
        __ bind(&packed_case);
      }
  
      ArraySingleArgumentConstructorStub stub(isolate(), kind, override_mode);
      CallCode(stub.GetCode(), RelocInfo::CONSTRUCT_CALL, instr);
      __ bind(&done);
    } else {
      ArrayNArgumentsConstructorStub stub(isolate(), kind, override_mode);
      CallCode(stub.GetCode(), RelocInfo::CONSTRUCT_CALL, instr);
    }
  }
  
  
  void LCodeGen::DoCallRuntime(LCallRuntime* instr) {
    DCHECK(ToRegister(instr->context()).is(rsi));
    CallRuntime(instr->function(), instr->arity(), instr, instr->save_doubles());
  }
  
  
  void LCodeGen::DoStoreCodeEntry(LStoreCodeEntry* instr) {
    Register function = ToRegister(instr->function());
    Register code_object = ToRegister(instr->code_object());
    __ leap(code_object, FieldOperand(code_object, Code::kHeaderSize));
    __ movp(FieldOperand(function, JSFunction::kCodeEntryOffset), code_object);
  }
  
  
  void LCodeGen::DoInnerAllocatedObject(LInnerAllocatedObject* instr) {
    Register result = ToRegister(instr->result());
    Register base = ToRegister(instr->base_object());
    if (instr->offset()->IsConstantOperand()) {
      LConstantOperand* offset = LConstantOperand::cast(instr->offset());
      __ leap(result, Operand(base, ToInteger32(offset)));
    } else {
      Register offset = ToRegister(instr->offset());
      __ leap(result, Operand(base, offset, times_1, 0));
    }
  }
  
  
  void LCodeGen::DoStoreNamedField(LStoreNamedField* instr) {
    HStoreNamedField* hinstr = instr->hydrogen();
    Representation representation = instr->representation();
  
    HObjectAccess access = hinstr->access();
    int offset = access.offset();
  
    if (access.IsExternalMemory()) {
      DCHECK(!hinstr->NeedsWriteBarrier());
      Register value = ToRegister(instr->value());
      if (instr->object()->IsConstantOperand()) {
        DCHECK(value.is(rax));
        LConstantOperand* object = LConstantOperand::cast(instr->object());
        __ store_rax(ToExternalReference(object));
      } else {
        Register object = ToRegister(instr->object());
        __ Store(MemOperand(object, offset), value, representation);
      }
      return;
    }
  
    Register object = ToRegister(instr->object());
    __ AssertNotSmi(object);
  
    DCHECK(!representation.IsSmi() ||
           !instr->value()->IsConstantOperand() ||
           IsInteger32Constant(LConstantOperand::cast(instr->value())));
    if (!FLAG_unbox_double_fields && representation.IsDouble()) {
      DCHECK(access.IsInobject());
      DCHECK(!hinstr->has_transition());
      DCHECK(!hinstr->NeedsWriteBarrier());
      XMMRegister value = ToDoubleRegister(instr->value());
      __ movsd(FieldOperand(object, offset), value);
      return;
    }
  
    if (hinstr->has_transition()) {
      Handle<Map> transition = hinstr->transition_map();
      AddDeprecationDependency(transition);
      if (!hinstr->NeedsWriteBarrierForMap()) {
        __ Move(FieldOperand(object, HeapObject::kMapOffset), transition);
      } else {
        Register temp = ToRegister(instr->temp());
        __ Move(kScratchRegister, transition);
        __ movp(FieldOperand(object, HeapObject::kMapOffset), kScratchRegister);
        // Update the write barrier for the map field.
        __ RecordWriteForMap(object,
                             kScratchRegister,
                             temp,
                             kSaveFPRegs);
      }
    }
  
    // Do the store.
    Register write_register = object;
    if (!access.IsInobject()) {
      write_register = ToRegister(instr->temp());
      __ movp(write_register, FieldOperand(object, JSObject::kPropertiesOffset));
    }
  
    if (representation.IsSmi() && SmiValuesAre32Bits() &&
        hinstr->value()->representation().IsInteger32()) {
      DCHECK(hinstr->store_mode() == STORE_TO_INITIALIZED_ENTRY);
      if (FLAG_debug_code) {
        Register scratch = kScratchRegister;
        __ Load(scratch, FieldOperand(write_register, offset), representation);
        __ AssertSmi(scratch);
      }
      // Store int value directly to upper half of the smi.
      STATIC_ASSERT(kSmiTag == 0);
      DCHECK(kSmiTagSize + kSmiShiftSize == 32);
      offset += kPointerSize / 2;
      representation = Representation::Integer32();
    }
  
    Operand operand = FieldOperand(write_register, offset);
  
    if (FLAG_unbox_double_fields && representation.IsDouble()) {
      DCHECK(access.IsInobject());
      XMMRegister value = ToDoubleRegister(instr->value());
      __ movsd(operand, value);
  
    } else if (instr->value()->IsRegister()) {
      Register value = ToRegister(instr->value());
      __ Store(operand, value, representation);
    } else {
      LConstantOperand* operand_value = LConstantOperand::cast(instr->value());
      if (IsInteger32Constant(operand_value)) {
        DCHECK(!hinstr->NeedsWriteBarrier());
        int32_t value = ToInteger32(operand_value);
        if (representation.IsSmi()) {
          __ Move(operand, Smi::FromInt(value));
  
        } else {
          __ movl(operand, Immediate(value));
        }
  
      } else {
        Handle<Object> handle_value = ToHandle(operand_value);
        DCHECK(!hinstr->NeedsWriteBarrier());
        __ Move(operand, handle_value);
      }
    }
  
    if (hinstr->NeedsWriteBarrier()) {
      Register value = ToRegister(instr->value());
      Register temp = access.IsInobject() ? ToRegister(instr->temp()) : object;
      // Update the write barrier for the object for in-object properties.
      __ RecordWriteField(write_register,
                          offset,
                          value,
                          temp,
                          kSaveFPRegs,
                          EMIT_REMEMBERED_SET,
                          hinstr->SmiCheckForWriteBarrier(),
                          hinstr->PointersToHereCheckForValue());
    }
  }
  
  
  void LCodeGen::DoStoreNamedGeneric(LStoreNamedGeneric* instr) {
    DCHECK(ToRegister(instr->context()).is(rsi));
    DCHECK(ToRegister(instr->object()).is(StoreDescriptor::ReceiverRegister()));
    DCHECK(ToRegister(instr->value()).is(StoreDescriptor::ValueRegister()));
  
    __ Move(StoreDescriptor::NameRegister(), instr->hydrogen()->name());
    Handle<Code> ic =
        StoreIC::initialize_stub(isolate(), instr->language_mode(),
                                 instr->hydrogen()->initialization_state());
    CallCode(ic, RelocInfo::CODE_TARGET, instr);
  }
  
  
  void LCodeGen::DoBoundsCheck(LBoundsCheck* instr) {
    Representation representation = instr->hydrogen()->length()->representation();
    DCHECK(representation.Equals(instr->hydrogen()->index()->representation()));
    DCHECK(representation.IsSmiOrInteger32());
  
    Condition cc = instr->hydrogen()->allow_equality() ? below : below_equal;
    if (instr->length()->IsConstantOperand()) {
      int32_t length = ToInteger32(LConstantOperand::cast(instr->length()));
      Register index = ToRegister(instr->index());
      if (representation.IsSmi()) {
        __ Cmp(index, Smi::FromInt(length));
      } else {
        __ cmpl(index, Immediate(length));
      }
      cc = CommuteCondition(cc);
    } else if (instr->index()->IsConstantOperand()) {
      int32_t index = ToInteger32(LConstantOperand::cast(instr->index()));
      if (instr->length()->IsRegister()) {
        Register length = ToRegister(instr->length());
        if (representation.IsSmi()) {
          __ Cmp(length, Smi::FromInt(index));
        } else {
          __ cmpl(length, Immediate(index));
        }
      } else {
        Operand length = ToOperand(instr->length());
        if (representation.IsSmi()) {
          __ Cmp(length, Smi::FromInt(index));
        } else {
          __ cmpl(length, Immediate(index));
        }
      }
    } else {
      Register index = ToRegister(instr->index());
      if (instr->length()->IsRegister()) {
        Register length = ToRegister(instr->length());
        if (representation.IsSmi()) {
          __ cmpp(length, index);
        } else {
          __ cmpl(length, index);
        }
      } else {
        Operand length = ToOperand(instr->length());
        if (representation.IsSmi()) {
          __ cmpp(length, index);
        } else {
          __ cmpl(length, index);
        }
      }
    }
    if (FLAG_debug_code && instr->hydrogen()->skip_check()) {
      Label done;
      __ j(NegateCondition(cc), &done, Label::kNear);
      __ int3();
      __ bind(&done);
    } else {
      DeoptimizeIf(cc, instr, Deoptimizer::kOutOfBounds);
    }
  }
  
  
  void LCodeGen::DoStoreKeyedExternalArray(LStoreKeyed* instr) {
    ElementsKind elements_kind = instr->elements_kind();
    LOperand* key = instr->key();
    if (kPointerSize == kInt32Size && !key->IsConstantOperand()) {
      Register key_reg = ToRegister(key);
      Representation key_representation =
          instr->hydrogen()->key()->representation();
      if (ExternalArrayOpRequiresTemp(key_representation, elements_kind)) {
        __ SmiToInteger64(key_reg, key_reg);
      } else if (instr->hydrogen()->IsDehoisted()) {
        // Sign extend key because it could be a 32 bit negative value
        // and the dehoisted address computation happens in 64 bits
        __ movsxlq(key_reg, key_reg);
      }
    }
    Operand operand(BuildFastArrayOperand(
        instr->elements(),
        key,
        instr->hydrogen()->key()->representation(),
        elements_kind,
        instr->base_offset()));
  
    if (elements_kind == EXTERNAL_FLOAT32_ELEMENTS ||
        elements_kind == FLOAT32_ELEMENTS) {
      XMMRegister value(ToDoubleRegister(instr->value()));
      __ cvtsd2ss(value, value);
      __ movss(operand, value);
    } else if (elements_kind == EXTERNAL_FLOAT64_ELEMENTS ||
               elements_kind == FLOAT64_ELEMENTS) {
      __ movsd(operand, ToDoubleRegister(instr->value()));
    } else {
      Register value(ToRegister(instr->value()));
      switch (elements_kind) {
        case EXTERNAL_UINT8_CLAMPED_ELEMENTS:
        case EXTERNAL_INT8_ELEMENTS:
        case EXTERNAL_UINT8_ELEMENTS:
        case INT8_ELEMENTS:
        case UINT8_ELEMENTS:
        case UINT8_CLAMPED_ELEMENTS:
          __ movb(operand, value);
          break;
        case EXTERNAL_INT16_ELEMENTS:
        case EXTERNAL_UINT16_ELEMENTS:
        case INT16_ELEMENTS:
        case UINT16_ELEMENTS:
          __ movw(operand, value);
          break;
        case EXTERNAL_INT32_ELEMENTS:
        case EXTERNAL_UINT32_ELEMENTS:
        case INT32_ELEMENTS:
        case UINT32_ELEMENTS:
          __ movl(operand, value);
          break;
        case EXTERNAL_FLOAT32_ELEMENTS:
        case EXTERNAL_FLOAT64_ELEMENTS:
        case FLOAT32_ELEMENTS:
        case FLOAT64_ELEMENTS:
        case FAST_ELEMENTS:
        case FAST_SMI_ELEMENTS:
        case FAST_DOUBLE_ELEMENTS:
        case FAST_HOLEY_ELEMENTS:
        case FAST_HOLEY_SMI_ELEMENTS:
        case FAST_HOLEY_DOUBLE_ELEMENTS:
        case DICTIONARY_ELEMENTS:
        case SLOPPY_ARGUMENTS_ELEMENTS:
          UNREACHABLE();
          break;
      }
    }
  }
  
  
  void LCodeGen::DoStoreKeyedFixedDoubleArray(LStoreKeyed* instr) {
    XMMRegister value = ToDoubleRegister(instr->value());
    LOperand* key = instr->key();
    if (kPointerSize == kInt32Size && !key->IsConstantOperand() &&
        instr->hydrogen()->IsDehoisted()) {
      // Sign extend key because it could be a 32 bit negative value
      // and the dehoisted address computation happens in 64 bits
      __ movsxlq(ToRegister(key), ToRegister(key));
    }
    if (instr->NeedsCanonicalization()) {
      XMMRegister xmm_scratch = double_scratch0();
      // Turn potential sNaN value into qNaN.
      __ xorps(xmm_scratch, xmm_scratch);
      __ subsd(value, xmm_scratch);
    }
  
    Operand double_store_operand = BuildFastArrayOperand(
        instr->elements(),
        key,
        instr->hydrogen()->key()->representation(),
        FAST_DOUBLE_ELEMENTS,
        instr->base_offset());
  
    __ movsd(double_store_operand, value);
  }
  
  
  void LCodeGen::DoStoreKeyedFixedArray(LStoreKeyed* instr) {
    HStoreKeyed* hinstr = instr->hydrogen();
    LOperand* key = instr->key();
    int offset = instr->base_offset();
    Representation representation = hinstr->value()->representation();
  
    if (kPointerSize == kInt32Size && !key->IsConstantOperand() &&
        instr->hydrogen()->IsDehoisted()) {
      // Sign extend key because it could be a 32 bit negative value
      // and the dehoisted address computation happens in 64 bits
      __ movsxlq(ToRegister(key), ToRegister(key));
    }
    if (representation.IsInteger32() && SmiValuesAre32Bits()) {
      DCHECK(hinstr->store_mode() == STORE_TO_INITIALIZED_ENTRY);
      DCHECK(hinstr->elements_kind() == FAST_SMI_ELEMENTS);
      if (FLAG_debug_code) {
        Register scratch = kScratchRegister;
        __ Load(scratch,
                BuildFastArrayOperand(instr->elements(),
                                      key,
                                      instr->hydrogen()->key()->representation(),
                                      FAST_ELEMENTS,
                                      offset),
                Representation::Smi());
        __ AssertSmi(scratch);
      }
      // Store int value directly to upper half of the smi.
      STATIC_ASSERT(kSmiTag == 0);
      DCHECK(kSmiTagSize + kSmiShiftSize == 32);
      offset += kPointerSize / 2;
    }
  
    Operand operand =
        BuildFastArrayOperand(instr->elements(),
                              key,
                              instr->hydrogen()->key()->representation(),
                              FAST_ELEMENTS,
                              offset);
    if (instr->value()->IsRegister()) {
      __ Store(operand, ToRegister(instr->value()), representation);
    } else {
      LConstantOperand* operand_value = LConstantOperand::cast(instr->value());
      if (IsInteger32Constant(operand_value)) {
        int32_t value = ToInteger32(operand_value);
        if (representation.IsSmi()) {
          __ Move(operand, Smi::FromInt(value));
  
        } else {
          __ movl(operand, Immediate(value));
        }
      } else {
        Handle<Object> handle_value = ToHandle(operand_value);
        __ Move(operand, handle_value);
      }
    }
  
    if (hinstr->NeedsWriteBarrier()) {
      Register elements = ToRegister(instr->elements());
      DCHECK(instr->value()->IsRegister());
      Register value = ToRegister(instr->value());
      DCHECK(!key->IsConstantOperand());
      SmiCheck check_needed = hinstr->value()->type().IsHeapObject()
              ? OMIT_SMI_CHECK : INLINE_SMI_CHECK;
      // Compute address of modified element and store it into key register.
      Register key_reg(ToRegister(key));
      __ leap(key_reg, operand);
      __ RecordWrite(elements,
                     key_reg,
                     value,
                     kSaveFPRegs,
                     EMIT_REMEMBERED_SET,
                     check_needed,
                     hinstr->PointersToHereCheckForValue());
    }
  }
  
  
  void LCodeGen::DoStoreKeyed(LStoreKeyed* instr) {
    if (instr->is_typed_elements()) {
      DoStoreKeyedExternalArray(instr);
    } else if (instr->hydrogen()->value()->representation().IsDouble()) {
      DoStoreKeyedFixedDoubleArray(instr);
    } else {
      DoStoreKeyedFixedArray(instr);
    }
  }
  
  
  void LCodeGen::DoStoreKeyedGeneric(LStoreKeyedGeneric* instr) {
    DCHECK(ToRegister(instr->context()).is(rsi));
    DCHECK(ToRegister(instr->object()).is(StoreDescriptor::ReceiverRegister()));
    DCHECK(ToRegister(instr->key()).is(StoreDescriptor::NameRegister()));
    DCHECK(ToRegister(instr->value()).is(StoreDescriptor::ValueRegister()));
  
    Handle<Code> ic = CodeFactory::KeyedStoreICInOptimizedCode(
                          isolate(), instr->language_mode(),
                          instr->hydrogen()->initialization_state()).code();
    CallCode(ic, RelocInfo::CODE_TARGET, instr);
  }
  
  
  void LCodeGen::DoMaybeGrowElements(LMaybeGrowElements* instr) {
    class DeferredMaybeGrowElements final : public LDeferredCode {
     public:
      DeferredMaybeGrowElements(LCodeGen* codegen, LMaybeGrowElements* instr)
          : LDeferredCode(codegen), instr_(instr) {}
      void Generate() override { codegen()->DoDeferredMaybeGrowElements(instr_); }
      LInstruction* instr() override { return instr_; }
  
     private:
      LMaybeGrowElements* instr_;
    };
  
    Register result = rax;
    DeferredMaybeGrowElements* deferred =
        new (zone()) DeferredMaybeGrowElements(this, instr);
    LOperand* key = instr->key();
    LOperand* current_capacity = instr->current_capacity();
  
    DCHECK(instr->hydrogen()->key()->representation().IsInteger32());
    DCHECK(instr->hydrogen()->current_capacity()->representation().IsInteger32());
    DCHECK(key->IsConstantOperand() || key->IsRegister());
    DCHECK(current_capacity->IsConstantOperand() ||
           current_capacity->IsRegister());
  
    if (key->IsConstantOperand() && current_capacity->IsConstantOperand()) {
      int32_t constant_key = ToInteger32(LConstantOperand::cast(key));
      int32_t constant_capacity =
          ToInteger32(LConstantOperand::cast(current_capacity));
      if (constant_key >= constant_capacity) {
        // Deferred case.
        __ jmp(deferred->entry());
      }
    } else if (key->IsConstantOperand()) {
      int32_t constant_key = ToInteger32(LConstantOperand::cast(key));
      __ cmpl(ToRegister(current_capacity), Immediate(constant_key));
      __ j(less_equal, deferred->entry());
    } else if (current_capacity->IsConstantOperand()) {
      int32_t constant_capacity =
          ToInteger32(LConstantOperand::cast(current_capacity));
      __ cmpl(ToRegister(key), Immediate(constant_capacity));
      __ j(greater_equal, deferred->entry());
    } else {
      __ cmpl(ToRegister(key), ToRegister(current_capacity));
      __ j(greater_equal, deferred->entry());
    }
  
    if (instr->elements()->IsRegister()) {
      __ movp(result, ToRegister(instr->elements()));
    } else {
      __ movp(result, ToOperand(instr->elements()));
    }
  
    __ bind(deferred->exit());
  }
  
  
  void LCodeGen::DoDeferredMaybeGrowElements(LMaybeGrowElements* instr) {
    // TODO(3095996): Get rid of this. For now, we need to make the
    // result register contain a valid pointer because it is already
    // contained in the register pointer map.
    Register result = rax;
    __ Move(result, Smi::FromInt(0));
  
    // We have to call a stub.
    {
      PushSafepointRegistersScope scope(this);
      if (instr->object()->IsConstantOperand()) {
        LConstantOperand* constant_object =
            LConstantOperand::cast(instr->object());
        if (IsSmiConstant(constant_object)) {
          Smi* immediate = ToSmi(constant_object);
          __ Move(result, immediate);
        } else {
          Handle<Object> handle_value = ToHandle(constant_object);
          __ Move(result, handle_value);
        }
      } else if (instr->object()->IsRegister()) {
        __ Move(result, ToRegister(instr->object()));
      } else {
        __ movp(result, ToOperand(instr->object()));
      }
  
      LOperand* key = instr->key();
      if (key->IsConstantOperand()) {
        __ Move(rbx, ToSmi(LConstantOperand::cast(key)));
      } else {
        __ Move(rbx, ToRegister(key));
        __ Integer32ToSmi(rbx, rbx);
      }
  
      GrowArrayElementsStub stub(isolate(), instr->hydrogen()->is_js_array(),
                                 instr->hydrogen()->kind());
      __ CallStub(&stub);
      RecordSafepointWithLazyDeopt(instr, RECORD_SAFEPOINT_WITH_REGISTERS, 0);
      __ StoreToSafepointRegisterSlot(result, result);
    }
  
    // Deopt on smi, which means the elements array changed to dictionary mode.
    Condition is_smi = __ CheckSmi(result);
    DeoptimizeIf(is_smi, instr, Deoptimizer::kSmi);
  }
  
  
  void LCodeGen::DoTransitionElementsKind(LTransitionElementsKind* instr) {
    Register object_reg = ToRegister(instr->object());
  
    Handle<Map> from_map = instr->original_map();
    Handle<Map> to_map = instr->transitioned_map();
    ElementsKind from_kind = instr->from_kind();
    ElementsKind to_kind = instr->to_kind();
  
    Label not_applicable;
    __ Cmp(FieldOperand(object_reg, HeapObject::kMapOffset), from_map);
    __ j(not_equal, &not_applicable);
    if (IsSimpleMapChangeTransition(from_kind, to_kind)) {
      Register new_map_reg = ToRegister(instr->new_map_temp());
      __ Move(new_map_reg, to_map, RelocInfo::EMBEDDED_OBJECT);
      __ movp(FieldOperand(object_reg, HeapObject::kMapOffset), new_map_reg);
      // Write barrier.
      __ RecordWriteForMap(object_reg, new_map_reg, ToRegister(instr->temp()),
                           kDontSaveFPRegs);
    } else {
      DCHECK(object_reg.is(rax));
      DCHECK(ToRegister(instr->context()).is(rsi));
      PushSafepointRegistersScope scope(this);
      __ Move(rbx, to_map);
      bool is_js_array = from_map->instance_type() == JS_ARRAY_TYPE;
      TransitionElementsKindStub stub(isolate(), from_kind, to_kind, is_js_array);
      __ CallStub(&stub);
      RecordSafepointWithLazyDeopt(instr, RECORD_SAFEPOINT_WITH_REGISTERS, 0);
    }
    __ bind(&not_applicable);
  }
  
  
  void LCodeGen::DoTrapAllocationMemento(LTrapAllocationMemento* instr) {
    Register object = ToRegister(instr->object());
    Register temp = ToRegister(instr->temp());
    Label no_memento_found;
    __ TestJSArrayForAllocationMemento(object, temp, &no_memento_found);
    DeoptimizeIf(equal, instr, Deoptimizer::kMementoFound);
    __ bind(&no_memento_found);
  }
  
  
  void LCodeGen::DoStringAdd(LStringAdd* instr) {
    DCHECK(ToRegister(instr->context()).is(rsi));
    DCHECK(ToRegister(instr->left()).is(rdx));
    DCHECK(ToRegister(instr->right()).is(rax));
    StringAddStub stub(isolate(),
                       instr->hydrogen()->flags(),
                       instr->hydrogen()->pretenure_flag());
    CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
  }
  
  
  void LCodeGen::DoStringCharCodeAt(LStringCharCodeAt* instr) {
    class DeferredStringCharCodeAt final : public LDeferredCode {
     public:
      DeferredStringCharCodeAt(LCodeGen* codegen, LStringCharCodeAt* instr)
          : LDeferredCode(codegen), instr_(instr) { }
      void Generate() override { codegen()->DoDeferredStringCharCodeAt(instr_); }
      LInstruction* instr() override { return instr_; }
  
     private:
      LStringCharCodeAt* instr_;
    };
  
    DeferredStringCharCodeAt* deferred =
        new(zone()) DeferredStringCharCodeAt(this, instr);
  
    StringCharLoadGenerator::Generate(masm(),
                                      ToRegister(instr->string()),
                                      ToRegister(instr->index()),
                                      ToRegister(instr->result()),
                                      deferred->entry());
    __ bind(deferred->exit());
  }
  
  
  void LCodeGen::DoDeferredStringCharCodeAt(LStringCharCodeAt* instr) {
    Register string = ToRegister(instr->string());
    Register result = ToRegister(instr->result());
  
    // TODO(3095996): Get rid of this. For now, we need to make the
    // result register contain a valid pointer because it is already
    // contained in the register pointer map.
    __ Set(result, 0);
  
    PushSafepointRegistersScope scope(this);
    __ Push(string);
    // Push the index as a smi. This is safe because of the checks in
    // DoStringCharCodeAt above.
    STATIC_ASSERT(String::kMaxLength <= Smi::kMaxValue);
    if (instr->index()->IsConstantOperand()) {
      int32_t const_index = ToInteger32(LConstantOperand::cast(instr->index()));
      __ Push(Smi::FromInt(const_index));
    } else {
      Register index = ToRegister(instr->index());
      __ Integer32ToSmi(index, index);
      __ Push(index);
    }
    CallRuntimeFromDeferred(
        Runtime::kStringCharCodeAtRT, 2, instr, instr->context());
    __ AssertSmi(rax);
    __ SmiToInteger32(rax, rax);
    __ StoreToSafepointRegisterSlot(result, rax);
  }
  
  
  void LCodeGen::DoStringCharFromCode(LStringCharFromCode* instr) {
    class DeferredStringCharFromCode final : public LDeferredCode {
     public:
      DeferredStringCharFromCode(LCodeGen* codegen, LStringCharFromCode* instr)
          : LDeferredCode(codegen), instr_(instr) { }
      void Generate() override {
        codegen()->DoDeferredStringCharFromCode(instr_);
      }
      LInstruction* instr() override { return instr_; }
  
     private:
      LStringCharFromCode* instr_;
    };
  
    DeferredStringCharFromCode* deferred =
        new(zone()) DeferredStringCharFromCode(this, instr);
  
    DCHECK(instr->hydrogen()->value()->representation().IsInteger32());
    Register char_code = ToRegister(instr->char_code());
    Register result = ToRegister(instr->result());
    DCHECK(!char_code.is(result));
  
    __ cmpl(char_code, Immediate(String::kMaxOneByteCharCode));
    __ j(above, deferred->entry());
    __ movsxlq(char_code, char_code);
    __ LoadRoot(result, Heap::kSingleCharacterStringCacheRootIndex);
    __ movp(result, FieldOperand(result,
                                 char_code, times_pointer_size,
                                 FixedArray::kHeaderSize));
    __ CompareRoot(result, Heap::kUndefinedValueRootIndex);
    __ j(equal, deferred->entry());
    __ bind(deferred->exit());
  }
  
  
  void LCodeGen::DoDeferredStringCharFromCode(LStringCharFromCode* instr) {
    Register char_code = ToRegister(instr->char_code());
    Register result = ToRegister(instr->result());
  
    // TODO(3095996): Get rid of this. For now, we need to make the
    // result register contain a valid pointer because it is already
    // contained in the register pointer map.
    __ Set(result, 0);
  
    PushSafepointRegistersScope scope(this);
    __ Integer32ToSmi(char_code, char_code);
    __ Push(char_code);
    CallRuntimeFromDeferred(Runtime::kCharFromCode, 1, instr, instr->context());
    __ StoreToSafepointRegisterSlot(result, rax);
  }
  
  
  void LCodeGen::DoInteger32ToDouble(LInteger32ToDouble* instr) {
    LOperand* input = instr->value();
    DCHECK(input->IsRegister() || input->IsStackSlot());
    LOperand* output = instr->result();
    DCHECK(output->IsDoubleRegister());
    if (input->IsRegister()) {
      __ Cvtlsi2sd(ToDoubleRegister(output), ToRegister(input));
    } else {
      __ Cvtlsi2sd(ToDoubleRegister(output), ToOperand(input));
    }
  }
  
  
  void LCodeGen::DoUint32ToDouble(LUint32ToDouble* instr) {
    LOperand* input = instr->value();
    LOperand* output = instr->result();
  
    __ LoadUint32(ToDoubleRegister(output), ToRegister(input));
  }
  
  
  void LCodeGen::DoNumberTagI(LNumberTagI* instr) {
    class DeferredNumberTagI final : public LDeferredCode {
     public:
      DeferredNumberTagI(LCodeGen* codegen, LNumberTagI* instr)
          : LDeferredCode(codegen), instr_(instr) { }
      void Generate() override {
        codegen()->DoDeferredNumberTagIU(instr_, instr_->value(), instr_->temp1(),
                                         instr_->temp2(), SIGNED_INT32);
      }
      LInstruction* instr() override { return instr_; }
  
     private:
      LNumberTagI* instr_;
    };
  
    LOperand* input = instr->value();
    DCHECK(input->IsRegister() && input->Equals(instr->result()));
    Register reg = ToRegister(input);
  
    if (SmiValuesAre32Bits()) {
      __ Integer32ToSmi(reg, reg);
    } else {
      DCHECK(SmiValuesAre31Bits());
      DeferredNumberTagI* deferred = new(zone()) DeferredNumberTagI(this, instr);
      __ Integer32ToSmi(reg, reg);
      __ j(overflow, deferred->entry());
      __ bind(deferred->exit());
    }
  }
  
  
  void LCodeGen::DoNumberTagU(LNumberTagU* instr) {
    class DeferredNumberTagU final : public LDeferredCode {
     public:
      DeferredNumberTagU(LCodeGen* codegen, LNumberTagU* instr)
          : LDeferredCode(codegen), instr_(instr) { }
      void Generate() override {
        codegen()->DoDeferredNumberTagIU(instr_, instr_->value(), instr_->temp1(),
                                         instr_->temp2(), UNSIGNED_INT32);
      }
      LInstruction* instr() override { return instr_; }
  
     private:
      LNumberTagU* instr_;
    };
  
    LOperand* input = instr->value();
    DCHECK(input->IsRegister() && input->Equals(instr->result()));
    Register reg = ToRegister(input);
  
    DeferredNumberTagU* deferred = new(zone()) DeferredNumberTagU(this, instr);
    __ cmpl(reg, Immediate(Smi::kMaxValue));
    __ j(above, deferred->entry());
    __ Integer32ToSmi(reg, reg);
    __ bind(deferred->exit());
  }
  
  
  void LCodeGen::DoDeferredNumberTagIU(LInstruction* instr,
                                       LOperand* value,
                                       LOperand* temp1,
                                       LOperand* temp2,
                                       IntegerSignedness signedness) {
    Label done, slow;
    Register reg = ToRegister(value);
    Register tmp = ToRegister(temp1);
    XMMRegister temp_xmm = ToDoubleRegister(temp2);
  
    // Load value into temp_xmm which will be preserved across potential call to
    // runtime (MacroAssembler::EnterExitFrameEpilogue preserves only allocatable
    // XMM registers on x64).
    if (signedness == SIGNED_INT32) {
      DCHECK(SmiValuesAre31Bits());
      // There was overflow, so bits 30 and 31 of the original integer
      // disagree. Try to allocate a heap number in new space and store
      // the value in there. If that fails, call the runtime system.
      __ SmiToInteger32(reg, reg);
      __ xorl(reg, Immediate(0x80000000));
      __ cvtlsi2sd(temp_xmm, reg);
    } else {
      DCHECK(signedness == UNSIGNED_INT32);
      __ LoadUint32(temp_xmm, reg);
    }
  
    if (FLAG_inline_new) {
      __ AllocateHeapNumber(reg, tmp, &slow);
      __ jmp(&done, kPointerSize == kInt64Size ? Label::kNear : Label::kFar);
    }
  
    // Slow case: Call the runtime system to do the number allocation.
    __ bind(&slow);
    {
      // Put a valid pointer value in the stack slot where the result
      // register is stored, as this register is in the pointer map, but contains
      // an integer value.
      __ Set(reg, 0);
  
      // Preserve the value of all registers.
      PushSafepointRegistersScope scope(this);
  
      // NumberTagIU uses the context from the frame, rather than
      // the environment's HContext or HInlinedContext value.
      // They only call Runtime::kAllocateHeapNumber.
      // The corresponding HChange instructions are added in a phase that does
      // not have easy access to the local context.
      __ movp(rsi, Operand(rbp, StandardFrameConstants::kContextOffset));
      __ CallRuntimeSaveDoubles(Runtime::kAllocateHeapNumber);
      RecordSafepointWithRegisters(
          instr->pointer_map(), 0, Safepoint::kNoLazyDeopt);
      __ StoreToSafepointRegisterSlot(reg, rax);
    }
  
    // Done. Put the value in temp_xmm into the value of the allocated heap
    // number.
    __ bind(&done);
    __ movsd(FieldOperand(reg, HeapNumber::kValueOffset), temp_xmm);
  }
  
  
  void LCodeGen::DoNumberTagD(LNumberTagD* instr) {
    class DeferredNumberTagD final : public LDeferredCode {
     public:
      DeferredNumberTagD(LCodeGen* codegen, LNumberTagD* instr)
          : LDeferredCode(codegen), instr_(instr) { }
      void Generate() override { codegen()->DoDeferredNumberTagD(instr_); }
      LInstruction* instr() override { return instr_; }
  
     private:
      LNumberTagD* instr_;
    };
  
    XMMRegister input_reg = ToDoubleRegister(instr->value());
    Register reg = ToRegister(instr->result());
    Register tmp = ToRegister(instr->temp());
  
    DeferredNumberTagD* deferred = new(zone()) DeferredNumberTagD(this, instr);
    if (FLAG_inline_new) {
      __ AllocateHeapNumber(reg, tmp, deferred->entry());
    } else {
      __ jmp(deferred->entry());
    }
    __ bind(deferred->exit());
    __ movsd(FieldOperand(reg, HeapNumber::kValueOffset), input_reg);
  }
  
  
  void LCodeGen::DoDeferredNumberTagD(LNumberTagD* instr) {
    // TODO(3095996): Get rid of this. For now, we need to make the
    // result register contain a valid pointer because it is already
    // contained in the register pointer map.
    Register reg = ToRegister(instr->result());
    __ Move(reg, Smi::FromInt(0));
  
    {
      PushSafepointRegistersScope scope(this);
      // NumberTagD uses the context from the frame, rather than
      // the environment's HContext or HInlinedContext value.
      // They only call Runtime::kAllocateHeapNumber.
      // The corresponding HChange instructions are added in a phase that does
      // not have easy access to the local context.
      __ movp(rsi, Operand(rbp, StandardFrameConstants::kContextOffset));
      __ CallRuntimeSaveDoubles(Runtime::kAllocateHeapNumber);
      RecordSafepointWithRegisters(
          instr->pointer_map(), 0, Safepoint::kNoLazyDeopt);
      __ movp(kScratchRegister, rax);
    }
    __ movp(reg, kScratchRegister);
  }
  
  
  void LCodeGen::DoSmiTag(LSmiTag* instr) {
    HChange* hchange = instr->hydrogen();
    Register input = ToRegister(instr->value());
    Register output = ToRegister(instr->result());
    if (hchange->CheckFlag(HValue::kCanOverflow) &&
        hchange->value()->CheckFlag(HValue::kUint32)) {
      Condition is_smi = __ CheckUInteger32ValidSmiValue(input);
      DeoptimizeIf(NegateCondition(is_smi), instr, Deoptimizer::kOverflow);
    }
    __ Integer32ToSmi(output, input);
    if (hchange->CheckFlag(HValue::kCanOverflow) &&
        !hchange->value()->CheckFlag(HValue::kUint32)) {
      DeoptimizeIf(overflow, instr, Deoptimizer::kOverflow);
    }
  }
  
  
  void LCodeGen::DoSmiUntag(LSmiUntag* instr) {
    DCHECK(instr->value()->Equals(instr->result()));
    Register input = ToRegister(instr->value());
    if (instr->needs_check()) {
      Condition is_smi = __ CheckSmi(input);
      DeoptimizeIf(NegateCondition(is_smi), instr, Deoptimizer::kNotASmi);
    } else {
      __ AssertSmi(input);
    }
    __ SmiToInteger32(input, input);
  }
  
  
  void LCodeGen::EmitNumberUntagD(LNumberUntagD* instr, Register input_reg,
                                  XMMRegister result_reg, NumberUntagDMode mode) {
    bool can_convert_undefined_to_nan =
        instr->hydrogen()->can_convert_undefined_to_nan();
    bool deoptimize_on_minus_zero = instr->hydrogen()->deoptimize_on_minus_zero();
  
    Label convert, load_smi, done;
  
    if (mode == NUMBER_CANDIDATE_IS_ANY_TAGGED) {
      // Smi check.
      __ JumpIfSmi(input_reg, &load_smi, Label::kNear);
  
      // Heap number map check.
      __ CompareRoot(FieldOperand(input_reg, HeapObject::kMapOffset),
                     Heap::kHeapNumberMapRootIndex);
  
      // On x64 it is safe to load at heap number offset before evaluating the map
      // check, since all heap objects are at least two words long.
      __ movsd(result_reg, FieldOperand(input_reg, HeapNumber::kValueOffset));
  
      if (can_convert_undefined_to_nan) {
        __ j(not_equal, &convert, Label::kNear);
      } else {
        DeoptimizeIf(not_equal, instr, Deoptimizer::kNotAHeapNumber);
      }
  
      if (deoptimize_on_minus_zero) {
        XMMRegister xmm_scratch = double_scratch0();
        __ xorps(xmm_scratch, xmm_scratch);
        __ ucomisd(xmm_scratch, result_reg);
        __ j(not_equal, &done, Label::kNear);
        __ movmskpd(kScratchRegister, result_reg);
        __ testq(kScratchRegister, Immediate(1));
        DeoptimizeIf(not_zero, instr, Deoptimizer::kMinusZero);
      }
      __ jmp(&done, Label::kNear);
  
      if (can_convert_undefined_to_nan) {
        __ bind(&convert);
  
        // Convert undefined (and hole) to NaN. Compute NaN as 0/0.
        __ CompareRoot(input_reg, Heap::kUndefinedValueRootIndex);
        DeoptimizeIf(not_equal, instr, Deoptimizer::kNotAHeapNumberUndefined);
  
        __ pcmpeqd(result_reg, result_reg);
        __ jmp(&done, Label::kNear);
      }
    } else {
      DCHECK(mode == NUMBER_CANDIDATE_IS_SMI);
    }
  
    // Smi to XMM conversion
    __ bind(&load_smi);
    __ SmiToInteger32(kScratchRegister, input_reg);
    __ Cvtlsi2sd(result_reg, kScratchRegister);
    __ bind(&done);
  }
  
  
  void LCodeGen::DoDeferredTaggedToI(LTaggedToI* instr, Label* done) {
    Register input_reg = ToRegister(instr->value());
  
    if (instr->truncating()) {
      Label no_heap_number, check_bools, check_false;
  
      // Heap number map check.
      __ CompareRoot(FieldOperand(input_reg, HeapObject::kMapOffset),
                     Heap::kHeapNumberMapRootIndex);
      __ j(not_equal, &no_heap_number, Label::kNear);
      __ TruncateHeapNumberToI(input_reg, input_reg);
      __ jmp(done);
  
      __ bind(&no_heap_number);
      // Check for Oddballs. Undefined/False is converted to zero and True to one
      // for truncating conversions.
      __ CompareRoot(input_reg, Heap::kUndefinedValueRootIndex);
      __ j(not_equal, &check_bools, Label::kNear);
      __ Set(input_reg, 0);
      __ jmp(done);
  
      __ bind(&check_bools);
      __ CompareRoot(input_reg, Heap::kTrueValueRootIndex);
      __ j(not_equal, &check_false, Label::kNear);
      __ Set(input_reg, 1);
      __ jmp(done);
  
      __ bind(&check_false);
      __ CompareRoot(input_reg, Heap::kFalseValueRootIndex);
      DeoptimizeIf(not_equal, instr,
                   Deoptimizer::kNotAHeapNumberUndefinedBoolean);
      __ Set(input_reg, 0);
    } else {
      XMMRegister scratch = ToDoubleRegister(instr->temp());
      DCHECK(!scratch.is(xmm0));
      __ CompareRoot(FieldOperand(input_reg, HeapObject::kMapOffset),
                     Heap::kHeapNumberMapRootIndex);
      DeoptimizeIf(not_equal, instr, Deoptimizer::kNotAHeapNumber);
      __ movsd(xmm0, FieldOperand(input_reg, HeapNumber::kValueOffset));
      __ cvttsd2si(input_reg, xmm0);
      __ Cvtlsi2sd(scratch, input_reg);
      __ ucomisd(xmm0, scratch);
      DeoptimizeIf(not_equal, instr, Deoptimizer::kLostPrecision);
      DeoptimizeIf(parity_even, instr, Deoptimizer::kNaN);
      if (instr->hydrogen()->GetMinusZeroMode() == FAIL_ON_MINUS_ZERO) {
        __ testl(input_reg, input_reg);
        __ j(not_zero, done);
        __ movmskpd(input_reg, xmm0);
        __ andl(input_reg, Immediate(1));
        DeoptimizeIf(not_zero, instr, Deoptimizer::kMinusZero);
      }
    }
  }
  
  
  void LCodeGen::DoTaggedToI(LTaggedToI* instr) {
    class DeferredTaggedToI final : public LDeferredCode {
     public:
      DeferredTaggedToI(LCodeGen* codegen, LTaggedToI* instr)
          : LDeferredCode(codegen), instr_(instr) { }
      void Generate() override { codegen()->DoDeferredTaggedToI(instr_, done()); }
      LInstruction* instr() override { return instr_; }
  
     private:
      LTaggedToI* instr_;
    };
  
    LOperand* input = instr->value();
    DCHECK(input->IsRegister());
    DCHECK(input->Equals(instr->result()));
    Register input_reg = ToRegister(input);
  
    if (instr->hydrogen()->value()->representation().IsSmi()) {
      __ SmiToInteger32(input_reg, input_reg);
    } else {
      DeferredTaggedToI* deferred = new(zone()) DeferredTaggedToI(this, instr);
      __ JumpIfNotSmi(input_reg, deferred->entry());
      __ SmiToInteger32(input_reg, input_reg);
      __ bind(deferred->exit());
    }
  }
  
  
  void LCodeGen::DoNumberUntagD(LNumberUntagD* instr) {
    LOperand* input = instr->value();
    DCHECK(input->IsRegister());
    LOperand* result = instr->result();
    DCHECK(result->IsDoubleRegister());
  
    Register input_reg = ToRegister(input);
    XMMRegister result_reg = ToDoubleRegister(result);
  
    HValue* value = instr->hydrogen()->value();
    NumberUntagDMode mode = value->representation().IsSmi()
        ? NUMBER_CANDIDATE_IS_SMI : NUMBER_CANDIDATE_IS_ANY_TAGGED;
  
    EmitNumberUntagD(instr, input_reg, result_reg, mode);
  }
  
  
  void LCodeGen::DoDoubleToI(LDoubleToI* instr) {
    LOperand* input = instr->value();
    DCHECK(input->IsDoubleRegister());
    LOperand* result = instr->result();
    DCHECK(result->IsRegister());
  
    XMMRegister input_reg = ToDoubleRegister(input);
    Register result_reg = ToRegister(result);
  
    if (instr->truncating()) {
      __ TruncateDoubleToI(result_reg, input_reg);
    } else {
      Label lost_precision, is_nan, minus_zero, done;
      XMMRegister xmm_scratch = double_scratch0();
      Label::Distance dist = DeoptEveryNTimes() ? Label::kFar : Label::kNear;
      __ DoubleToI(result_reg, input_reg, xmm_scratch,
                   instr->hydrogen()->GetMinusZeroMode(), &lost_precision,
                   &is_nan, &minus_zero, dist);
      __ jmp(&done, dist);
      __ bind(&lost_precision);
      DeoptimizeIf(no_condition, instr, Deoptimizer::kLostPrecision);
      __ bind(&is_nan);
      DeoptimizeIf(no_condition, instr, Deoptimizer::kNaN);
      __ bind(&minus_zero);
      DeoptimizeIf(no_condition, instr, Deoptimizer::kMinusZero);
      __ bind(&done);
    }
  }
  
  
  void LCodeGen::DoDoubleToSmi(LDoubleToSmi* instr) {
    LOperand* input = instr->value();
    DCHECK(input->IsDoubleRegister());
    LOperand* result = instr->result();
    DCHECK(result->IsRegister());
  
    XMMRegister input_reg = ToDoubleRegister(input);
    Register result_reg = ToRegister(result);
  
    Label lost_precision, is_nan, minus_zero, done;
    XMMRegister xmm_scratch = double_scratch0();
    Label::Distance dist = DeoptEveryNTimes() ? Label::kFar : Label::kNear;
    __ DoubleToI(result_reg, input_reg, xmm_scratch,
                 instr->hydrogen()->GetMinusZeroMode(), &lost_precision, &is_nan,
                 &minus_zero, dist);
    __ jmp(&done, dist);
    __ bind(&lost_precision);
    DeoptimizeIf(no_condition, instr, Deoptimizer::kLostPrecision);
    __ bind(&is_nan);
    DeoptimizeIf(no_condition, instr, Deoptimizer::kNaN);
    __ bind(&minus_zero);
    DeoptimizeIf(no_condition, instr, Deoptimizer::kMinusZero);
    __ bind(&done);
    __ Integer32ToSmi(result_reg, result_reg);
    DeoptimizeIf(overflow, instr, Deoptimizer::kOverflow);
  }
  
  
  void LCodeGen::DoCheckSmi(LCheckSmi* instr) {
    LOperand* input = instr->value();
    Condition cc = masm()->CheckSmi(ToRegister(input));
    DeoptimizeIf(NegateCondition(cc), instr, Deoptimizer::kNotASmi);
  }
  
  
  void LCodeGen::DoCheckNonSmi(LCheckNonSmi* instr) {
    if (!instr->hydrogen()->value()->type().IsHeapObject()) {
      LOperand* input = instr->value();
      Condition cc = masm()->CheckSmi(ToRegister(input));
      DeoptimizeIf(cc, instr, Deoptimizer::kSmi);
    }
  }
  
  
  void LCodeGen::DoCheckArrayBufferNotNeutered(
      LCheckArrayBufferNotNeutered* instr) {
    Register view = ToRegister(instr->view());
  
    __ movp(kScratchRegister,
            FieldOperand(view, JSArrayBufferView::kBufferOffset));
    __ testb(FieldOperand(kScratchRegister, JSArrayBuffer::kBitFieldOffset),
             Immediate(1 << JSArrayBuffer::WasNeutered::kShift));
    DeoptimizeIf(not_zero, instr, Deoptimizer::kOutOfBounds);
  }
  
  
  void LCodeGen::DoCheckInstanceType(LCheckInstanceType* instr) {
    Register input = ToRegister(instr->value());
  
    __ movp(kScratchRegister, FieldOperand(input, HeapObject::kMapOffset));
  
    if (instr->hydrogen()->is_interval_check()) {
      InstanceType first;
      InstanceType last;
      instr->hydrogen()->GetCheckInterval(&first, &last);
  
      __ cmpb(FieldOperand(kScratchRegister, Map::kInstanceTypeOffset),
              Immediate(static_cast<int8_t>(first)));
  
      // If there is only one type in the interval check for equality.
      if (first == last) {
        DeoptimizeIf(not_equal, instr, Deoptimizer::kWrongInstanceType);
      } else {
        DeoptimizeIf(below, instr, Deoptimizer::kWrongInstanceType);
        // Omit check for the last type.
        if (last != LAST_TYPE) {
          __ cmpb(FieldOperand(kScratchRegister, Map::kInstanceTypeOffset),
                  Immediate(static_cast<int8_t>(last)));
          DeoptimizeIf(above, instr, Deoptimizer::kWrongInstanceType);
        }
      }
    } else {
      uint8_t mask;
      uint8_t tag;
      instr->hydrogen()->GetCheckMaskAndTag(&mask, &tag);
  
      if (base::bits::IsPowerOfTwo32(mask)) {
        DCHECK(tag == 0 || base::bits::IsPowerOfTwo32(tag));
        __ testb(FieldOperand(kScratchRegister, Map::kInstanceTypeOffset),
                 Immediate(mask));
        DeoptimizeIf(tag == 0 ? not_zero : zero, instr,
                     Deoptimizer::kWrongInstanceType);
      } else {
        __ movzxbl(kScratchRegister,
                   FieldOperand(kScratchRegister, Map::kInstanceTypeOffset));
        __ andb(kScratchRegister, Immediate(mask));
        __ cmpb(kScratchRegister, Immediate(tag));
        DeoptimizeIf(not_equal, instr, Deoptimizer::kWrongInstanceType);
      }
    }
  }
  
  
  void LCodeGen::DoCheckValue(LCheckValue* instr) {
    Register reg = ToRegister(instr->value());
    __ Cmp(reg, instr->hydrogen()->object().handle());
    DeoptimizeIf(not_equal, instr, Deoptimizer::kValueMismatch);
  }
  
  
  void LCodeGen::DoDeferredInstanceMigration(LCheckMaps* instr, Register object) {
    {
      PushSafepointRegistersScope scope(this);
      __ Push(object);
      __ Set(rsi, 0);
      __ CallRuntimeSaveDoubles(Runtime::kTryMigrateInstance);
      RecordSafepointWithRegisters(
          instr->pointer_map(), 1, Safepoint::kNoLazyDeopt);
  
      __ testp(rax, Immediate(kSmiTagMask));
    }
    DeoptimizeIf(zero, instr, Deoptimizer::kInstanceMigrationFailed);
  }
  
  
  void LCodeGen::DoCheckMaps(LCheckMaps* instr) {
    class DeferredCheckMaps final : public LDeferredCode {
     public:
      DeferredCheckMaps(LCodeGen* codegen, LCheckMaps* instr, Register object)
          : LDeferredCode(codegen), instr_(instr), object_(object) {
        SetExit(check_maps());
      }
      void Generate() override {
        codegen()->DoDeferredInstanceMigration(instr_, object_);
      }
      Label* check_maps() { return &check_maps_; }
      LInstruction* instr() override { return instr_; }
  
     private:
      LCheckMaps* instr_;
      Label check_maps_;
      Register object_;
    };
  
    if (instr->hydrogen()->IsStabilityCheck()) {
      const UniqueSet<Map>* maps = instr->hydrogen()->maps();
      for (int i = 0; i < maps->size(); ++i) {
        AddStabilityDependency(maps->at(i).handle());
      }
      return;
    }
  
    LOperand* input = instr->value();
    DCHECK(input->IsRegister());
    Register reg = ToRegister(input);
  
    DeferredCheckMaps* deferred = NULL;
    if (instr->hydrogen()->HasMigrationTarget()) {
      deferred = new(zone()) DeferredCheckMaps(this, instr, reg);
      __ bind(deferred->check_maps());
    }
  
    const UniqueSet<Map>* maps = instr->hydrogen()->maps();
    Label success;
    for (int i = 0; i < maps->size() - 1; i++) {
      Handle<Map> map = maps->at(i).handle();
      __ CompareMap(reg, map);
      __ j(equal, &success, Label::kNear);
    }
  
    Handle<Map> map = maps->at(maps->size() - 1).handle();
    __ CompareMap(reg, map);
    if (instr->hydrogen()->HasMigrationTarget()) {
      __ j(not_equal, deferred->entry());
    } else {
      DeoptimizeIf(not_equal, instr, Deoptimizer::kWrongMap);
    }
  
    __ bind(&success);
  }
  
  
  void LCodeGen::DoClampDToUint8(LClampDToUint8* instr) {
    XMMRegister value_reg = ToDoubleRegister(instr->unclamped());
    XMMRegister xmm_scratch = double_scratch0();
    Register result_reg = ToRegister(instr->result());
    __ ClampDoubleToUint8(value_reg, xmm_scratch, result_reg);
  }
  
  
  void LCodeGen::DoClampIToUint8(LClampIToUint8* instr) {
    DCHECK(instr->unclamped()->Equals(instr->result()));
    Register value_reg = ToRegister(instr->result());
    __ ClampUint8(value_reg);
  }
  
  
  void LCodeGen::DoClampTToUint8(LClampTToUint8* instr) {
    DCHECK(instr->unclamped()->Equals(instr->result()));
    Register input_reg = ToRegister(instr->unclamped());
    XMMRegister temp_xmm_reg = ToDoubleRegister(instr->temp_xmm());
    XMMRegister xmm_scratch = double_scratch0();
    Label is_smi, done, heap_number;
    Label::Distance dist = DeoptEveryNTimes() ? Label::kFar : Label::kNear;
    __ JumpIfSmi(input_reg, &is_smi, dist);
  
    // Check for heap number
    __ Cmp(FieldOperand(input_reg, HeapObject::kMapOffset),
           factory()->heap_number_map());
    __ j(equal, &heap_number, Label::kNear);
  
    // Check for undefined. Undefined is converted to zero for clamping
    // conversions.
    __ Cmp(input_reg, factory()->undefined_value());
    DeoptimizeIf(not_equal, instr, Deoptimizer::kNotAHeapNumberUndefined);
    __ xorl(input_reg, input_reg);
    __ jmp(&done, Label::kNear);
  
    // Heap number
    __ bind(&heap_number);
    __ movsd(xmm_scratch, FieldOperand(input_reg, HeapNumber::kValueOffset));
    __ ClampDoubleToUint8(xmm_scratch, temp_xmm_reg, input_reg);
    __ jmp(&done, Label::kNear);
  
    // smi
    __ bind(&is_smi);
    __ SmiToInteger32(input_reg, input_reg);
    __ ClampUint8(input_reg);
  
    __ bind(&done);
  }
  
  
  void LCodeGen::DoDoubleBits(LDoubleBits* instr) {
    XMMRegister value_reg = ToDoubleRegister(instr->value());
    Register result_reg = ToRegister(instr->result());
    if (instr->hydrogen()->bits() == HDoubleBits::HIGH) {
      __ movq(result_reg, value_reg);
      __ shrq(result_reg, Immediate(32));
    } else {
      __ movd(result_reg, value_reg);
    }
  }
  
  
  void LCodeGen::DoConstructDouble(LConstructDouble* instr) {
    Register hi_reg = ToRegister(instr->hi());
    Register lo_reg = ToRegister(instr->lo());
    XMMRegister result_reg = ToDoubleRegister(instr->result());
    XMMRegister xmm_scratch = double_scratch0();
    __ movd(result_reg, hi_reg);
    __ psllq(result_reg, 32);
    __ movd(xmm_scratch, lo_reg);
    __ orps(result_reg, xmm_scratch);
  }
  
  
  void LCodeGen::DoAllocate(LAllocate* instr) {
    class DeferredAllocate final : public LDeferredCode {
     public:
      DeferredAllocate(LCodeGen* codegen, LAllocate* instr)
          : LDeferredCode(codegen), instr_(instr) { }
      void Generate() override { codegen()->DoDeferredAllocate(instr_); }
      LInstruction* instr() override { return instr_; }
  
     private:
      LAllocate* instr_;
    };
  
    DeferredAllocate* deferred =
        new(zone()) DeferredAllocate(this, instr);
  
    Register result = ToRegister(instr->result());
    Register temp = ToRegister(instr->temp());
  
    // Allocate memory for the object.
    AllocationFlags flags = TAG_OBJECT;
    if (instr->hydrogen()->MustAllocateDoubleAligned()) {
      flags = static_cast<AllocationFlags>(flags | DOUBLE_ALIGNMENT);
    }
    if (instr->hydrogen()->IsOldSpaceAllocation()) {
      DCHECK(!instr->hydrogen()->IsNewSpaceAllocation());
      flags = static_cast<AllocationFlags>(flags | PRETENURE);
    }
  
    if (instr->size()->IsConstantOperand()) {
      int32_t size = ToInteger32(LConstantOperand::cast(instr->size()));
      if (size <= Page::kMaxRegularHeapObjectSize) {
        __ Allocate(size, result, temp, no_reg, deferred->entry(), flags);
      } else {
        __ jmp(deferred->entry());
      }
    } else {
      Register size = ToRegister(instr->size());
      __ Allocate(size, result, temp, no_reg, deferred->entry(), flags);
    }
  
    __ bind(deferred->exit());
  
    if (instr->hydrogen()->MustPrefillWithFiller()) {
      if (instr->size()->IsConstantOperand()) {
        int32_t size = ToInteger32(LConstantOperand::cast(instr->size()));
        __ movl(temp, Immediate((size / kPointerSize) - 1));
      } else {
        temp = ToRegister(instr->size());
        __ sarp(temp, Immediate(kPointerSizeLog2));
        __ decl(temp);
      }
      Label loop;
      __ bind(&loop);
      __ Move(FieldOperand(result, temp, times_pointer_size, 0),
          isolate()->factory()->one_pointer_filler_map());
      __ decl(temp);
      __ j(not_zero, &loop);
    }
  }
  
  
  void LCodeGen::DoDeferredAllocate(LAllocate* instr) {
    Register result = ToRegister(instr->result());
  
    // TODO(3095996): Get rid of this. For now, we need to make the
    // result register contain a valid pointer because it is already
    // contained in the register pointer map.
    __ Move(result, Smi::FromInt(0));
  
    PushSafepointRegistersScope scope(this);
    if (instr->size()->IsRegister()) {
      Register size = ToRegister(instr->size());
      DCHECK(!size.is(result));
      __ Integer32ToSmi(size, size);
      __ Push(size);
    } else {
      int32_t size = ToInteger32(LConstantOperand::cast(instr->size()));
      __ Push(Smi::FromInt(size));
    }
  
    int flags = 0;
    if (instr->hydrogen()->IsOldSpaceAllocation()) {
      DCHECK(!instr->hydrogen()->IsNewSpaceAllocation());
      flags = AllocateTargetSpace::update(flags, OLD_SPACE);
    } else {
      flags = AllocateTargetSpace::update(flags, NEW_SPACE);
    }
    __ Push(Smi::FromInt(flags));
  
    CallRuntimeFromDeferred(
        Runtime::kAllocateInTargetSpace, 2, instr, instr->context());
    __ StoreToSafepointRegisterSlot(result, rax);
  }
  
  
  void LCodeGen::DoToFastProperties(LToFastProperties* instr) {
    DCHECK(ToRegister(instr->value()).is(rax));
    __ Push(rax);
    CallRuntime(Runtime::kToFastProperties, 1, instr);
  }
  
  
  void LCodeGen::DoRegExpLiteral(LRegExpLiteral* instr) {
    DCHECK(ToRegister(instr->context()).is(rsi));
    Label materialized;
    // Registers will be used as follows:
    // rcx = literals array.
    // rbx = regexp literal.
    // rax = regexp literal clone.
    int literal_offset =
        FixedArray::OffsetOfElementAt(instr->hydrogen()->literal_index());
    __ Move(rcx, instr->hydrogen()->literals());
    __ movp(rbx, FieldOperand(rcx, literal_offset));
    __ CompareRoot(rbx, Heap::kUndefinedValueRootIndex);
    __ j(not_equal, &materialized, Label::kNear);
  
    // Create regexp literal using runtime function
    // Result will be in rax.
    __ Push(rcx);
    __ Push(Smi::FromInt(instr->hydrogen()->literal_index()));
    __ Push(instr->hydrogen()->pattern());
    __ Push(instr->hydrogen()->flags());
    CallRuntime(Runtime::kMaterializeRegExpLiteral, 4, instr);
    __ movp(rbx, rax);
  
    __ bind(&materialized);
    int size = JSRegExp::kSize + JSRegExp::kInObjectFieldCount * kPointerSize;
    Label allocated, runtime_allocate;
    __ Allocate(size, rax, rcx, rdx, &runtime_allocate, TAG_OBJECT);
    __ jmp(&allocated, Label::kNear);
  
    __ bind(&runtime_allocate);
    __ Push(rbx);
    __ Push(Smi::FromInt(size));
    CallRuntime(Runtime::kAllocateInNewSpace, 1, instr);
    __ Pop(rbx);
  
    __ bind(&allocated);
    // Copy the content into the newly allocated memory.
    // (Unroll copy loop once for better throughput).
    for (int i = 0; i < size - kPointerSize; i += 2 * kPointerSize) {
      __ movp(rdx, FieldOperand(rbx, i));
      __ movp(rcx, FieldOperand(rbx, i + kPointerSize));
      __ movp(FieldOperand(rax, i), rdx);
      __ movp(FieldOperand(rax, i + kPointerSize), rcx);
    }
    if ((size % (2 * kPointerSize)) != 0) {
      __ movp(rdx, FieldOperand(rbx, size - kPointerSize));
      __ movp(FieldOperand(rax, size - kPointerSize), rdx);
    }
  }
  
  
  void LCodeGen::DoFunctionLiteral(LFunctionLiteral* instr) {
    DCHECK(ToRegister(instr->context()).is(rsi));
    // Use the fast case closure allocation code that allocates in new
    // space for nested functions that don't need literals cloning.
    bool pretenure = instr->hydrogen()->pretenure();
    if (!pretenure && instr->hydrogen()->has_no_literals()) {
      FastNewClosureStub stub(isolate(), instr->hydrogen()->language_mode(),
                              instr->hydrogen()->kind());
      __ Move(rbx, instr->hydrogen()->shared_info());
      CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
    } else {
      __ Push(rsi);
      __ Push(instr->hydrogen()->shared_info());
      __ PushRoot(pretenure ? Heap::kTrueValueRootIndex :
                              Heap::kFalseValueRootIndex);
      CallRuntime(Runtime::kNewClosure, 3, instr);
    }
  }
  
  
  void LCodeGen::DoTypeof(LTypeof* instr) {
    DCHECK(ToRegister(instr->context()).is(rsi));
    DCHECK(ToRegister(instr->value()).is(rbx));
    Label end, do_call;
    Register value_register = ToRegister(instr->value());
    __ JumpIfNotSmi(value_register, &do_call);
    __ Move(rax, isolate()->factory()->number_string());
    __ jmp(&end);
    __ bind(&do_call);
    TypeofStub stub(isolate());
    CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
    __ bind(&end);
  }
  
  
  void LCodeGen::EmitPushTaggedOperand(LOperand* operand) {
    DCHECK(!operand->IsDoubleRegister());
    if (operand->IsConstantOperand()) {
      __ Push(ToHandle(LConstantOperand::cast(operand)));
    } else if (operand->IsRegister()) {
      __ Push(ToRegister(operand));
    } else {
      __ Push(ToOperand(operand));
    }
  }
  
  
  void LCodeGen::DoTypeofIsAndBranch(LTypeofIsAndBranch* instr) {
    Register input = ToRegister(instr->value());
    Condition final_branch_condition = EmitTypeofIs(instr, input);
    if (final_branch_condition != no_condition) {
      EmitBranch(instr, final_branch_condition);
    }
  }
  
  
  Condition LCodeGen::EmitTypeofIs(LTypeofIsAndBranch* instr, Register input) {
    Label* true_label = instr->TrueLabel(chunk_);
    Label* false_label = instr->FalseLabel(chunk_);
    Handle<String> type_name = instr->type_literal();
    int left_block = instr->TrueDestination(chunk_);
    int right_block = instr->FalseDestination(chunk_);
    int next_block = GetNextEmittedBlock();
  
    Label::Distance true_distance = left_block == next_block ? Label::kNear
                                                             : Label::kFar;
    Label::Distance false_distance = right_block == next_block ? Label::kNear
                                                               : Label::kFar;
    Condition final_branch_condition = no_condition;
    Factory* factory = isolate()->factory();
    if (String::Equals(type_name, factory->number_string())) {
      __ JumpIfSmi(input, true_label, true_distance);
      __ CompareRoot(FieldOperand(input, HeapObject::kMapOffset),
                     Heap::kHeapNumberMapRootIndex);
  
      final_branch_condition = equal;
  
    } else if (String::Equals(type_name, factory->string_string())) {
      __ JumpIfSmi(input, false_label, false_distance);
      __ CmpObjectType(input, FIRST_NONSTRING_TYPE, input);
      __ j(above_equal, false_label, false_distance);
      __ testb(FieldOperand(input, Map::kBitFieldOffset),
               Immediate(1 << Map::kIsUndetectable));
      final_branch_condition = zero;
  
    } else if (String::Equals(type_name, factory->symbol_string())) {
      __ JumpIfSmi(input, false_label, false_distance);
      __ CmpObjectType(input, SYMBOL_TYPE, input);
      final_branch_condition = equal;
  
    } else if (String::Equals(type_name, factory->boolean_string())) {
      __ CompareRoot(input, Heap::kTrueValueRootIndex);
      __ j(equal, true_label, true_distance);
      __ CompareRoot(input, Heap::kFalseValueRootIndex);
      final_branch_condition = equal;
  
    } else if (String::Equals(type_name, factory->undefined_string())) {
      __ CompareRoot(input, Heap::kUndefinedValueRootIndex);
      __ j(equal, true_label, true_distance);
      __ JumpIfSmi(input, false_label, false_distance);
      // Check for undetectable objects => true.
      __ movp(input, FieldOperand(input, HeapObject::kMapOffset));
      __ testb(FieldOperand(input, Map::kBitFieldOffset),
               Immediate(1 << Map::kIsUndetectable));
      final_branch_condition = not_zero;
  
    } else if (String::Equals(type_name, factory->function_string())) {
      STATIC_ASSERT(NUM_OF_CALLABLE_SPEC_OBJECT_TYPES == 2);
      __ JumpIfSmi(input, false_label, false_distance);
      __ CmpObjectType(input, JS_FUNCTION_TYPE, input);
      __ j(equal, true_label, true_distance);
      __ CmpInstanceType(input, JS_FUNCTION_PROXY_TYPE);
      final_branch_condition = equal;
  
    } else if (String::Equals(type_name, factory->object_string())) {
      __ JumpIfSmi(input, false_label, false_distance);
      __ CompareRoot(input, Heap::kNullValueRootIndex);
      __ j(equal, true_label, true_distance);
      __ CmpObjectType(input, FIRST_NONCALLABLE_SPEC_OBJECT_TYPE, input);
      __ j(below, false_label, false_distance);
      __ CmpInstanceType(input, LAST_NONCALLABLE_SPEC_OBJECT_TYPE);
      __ j(above, false_label, false_distance);
      // Check for undetectable objects => false.
      __ testb(FieldOperand(input, Map::kBitFieldOffset),
               Immediate(1 << Map::kIsUndetectable));
      final_branch_condition = zero;
  
    } else {
      __ jmp(false_label, false_distance);
    }
  
    return final_branch_condition;
  }
  
  
  void LCodeGen::DoIsConstructCallAndBranch(LIsConstructCallAndBranch* instr) {
    Register temp = ToRegister(instr->temp());
  
    EmitIsConstructCall(temp);
    EmitBranch(instr, equal);
  }
  
  
  void LCodeGen::EmitIsConstructCall(Register temp) {
    // Get the frame pointer for the calling frame.
    __ movp(temp, Operand(rbp, StandardFrameConstants::kCallerFPOffset));
  
    // Skip the arguments adaptor frame if it exists.
    Label check_frame_marker;
    __ Cmp(Operand(temp, StandardFrameConstants::kContextOffset),
           Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR));
    __ j(not_equal, &check_frame_marker, Label::kNear);
    __ movp(temp, Operand(temp, StandardFrameConstants::kCallerFPOffset));
  
    // Check the marker in the calling frame.
    __ bind(&check_frame_marker);
    __ Cmp(Operand(temp, StandardFrameConstants::kMarkerOffset),
           Smi::FromInt(StackFrame::CONSTRUCT));
  }
  
  
  void LCodeGen::EnsureSpaceForLazyDeopt(int space_needed) {
    if (!info()->IsStub()) {
      // Ensure that we have enough space after the previous lazy-bailout
      // instruction for patching the code here.
      int current_pc = masm()->pc_offset();
      if (current_pc < last_lazy_deopt_pc_ + space_needed) {
        int padding_size = last_lazy_deopt_pc_ + space_needed - current_pc;
        __ Nop(padding_size);
      }
    }
    last_lazy_deopt_pc_ = masm()->pc_offset();
  }
  
  
  void LCodeGen::DoLazyBailout(LLazyBailout* instr) {
    last_lazy_deopt_pc_ = masm()->pc_offset();
    DCHECK(instr->HasEnvironment());
    LEnvironment* env = instr->environment();
    RegisterEnvironmentForDeoptimization(env, Safepoint::kLazyDeopt);
    safepoints_.RecordLazyDeoptimizationIndex(env->deoptimization_index());
  }
  
  
  void LCodeGen::DoDeoptimize(LDeoptimize* instr) {
    Deoptimizer::BailoutType type = instr->hydrogen()->type();
    // TODO(danno): Stubs expect all deopts to be lazy for historical reasons (the
    // needed return address), even though the implementation of LAZY and EAGER is
    // now identical. When LAZY is eventually completely folded into EAGER, remove
    // the special case below.
    if (info()->IsStub() && type == Deoptimizer::EAGER) {
      type = Deoptimizer::LAZY;
    }
    DeoptimizeIf(no_condition, instr, instr->hydrogen()->reason(), type);
  }
  
  
  void LCodeGen::DoDummy(LDummy* instr) {
    // Nothing to see here, move on!
  }
  
  
  void LCodeGen::DoDummyUse(LDummyUse* instr) {
    // Nothing to see here, move on!
  }
  
  
  void LCodeGen::DoDeferredStackCheck(LStackCheck* instr) {
    PushSafepointRegistersScope scope(this);
    __ movp(rsi, Operand(rbp, StandardFrameConstants::kContextOffset));
    __ CallRuntimeSaveDoubles(Runtime::kStackGuard);
    RecordSafepointWithLazyDeopt(instr, RECORD_SAFEPOINT_WITH_REGISTERS, 0);
    DCHECK(instr->HasEnvironment());
    LEnvironment* env = instr->environment();
    safepoints_.RecordLazyDeoptimizationIndex(env->deoptimization_index());
  }
  
  
  void LCodeGen::DoStackCheck(LStackCheck* instr) {
    class DeferredStackCheck final : public LDeferredCode {
     public:
      DeferredStackCheck(LCodeGen* codegen, LStackCheck* instr)
          : LDeferredCode(codegen), instr_(instr) { }
      void Generate() override { codegen()->DoDeferredStackCheck(instr_); }
      LInstruction* instr() override { return instr_; }
  
     private:
      LStackCheck* instr_;
    };
  
    DCHECK(instr->HasEnvironment());
    LEnvironment* env = instr->environment();
    // There is no LLazyBailout instruction for stack-checks. We have to
    // prepare for lazy deoptimization explicitly here.
    if (instr->hydrogen()->is_function_entry()) {
      // Perform stack overflow check.
      Label done;
      __ CompareRoot(rsp, Heap::kStackLimitRootIndex);
      __ j(above_equal, &done, Label::kNear);
  
      DCHECK(instr->context()->IsRegister());
      DCHECK(ToRegister(instr->context()).is(rsi));
      CallCode(isolate()->builtins()->StackCheck(),
               RelocInfo::CODE_TARGET,
               instr);
      __ bind(&done);
    } else {
      DCHECK(instr->hydrogen()->is_backwards_branch());
      // Perform stack overflow check if this goto needs it before jumping.
      DeferredStackCheck* deferred_stack_check =
          new(zone()) DeferredStackCheck(this, instr);
      __ CompareRoot(rsp, Heap::kStackLimitRootIndex);
      __ j(below, deferred_stack_check->entry());
      EnsureSpaceForLazyDeopt(Deoptimizer::patch_size());
      __ bind(instr->done_label());
      deferred_stack_check->SetExit(instr->done_label());
      RegisterEnvironmentForDeoptimization(env, Safepoint::kLazyDeopt);
      // Don't record a deoptimization index for the safepoint here.
      // This will be done explicitly when emitting call and the safepoint in
      // the deferred code.
    }
  }
  
  
  void LCodeGen::DoOsrEntry(LOsrEntry* instr) {
    // This is a pseudo-instruction that ensures that the environment here is
    // properly registered for deoptimization and records the assembler's PC
    // offset.
    LEnvironment* environment = instr->environment();
  
    // If the environment were already registered, we would have no way of
    // backpatching it with the spill slot operands.
    DCHECK(!environment->HasBeenRegistered());
    RegisterEnvironmentForDeoptimization(environment, Safepoint::kNoLazyDeopt);
  
    GenerateOsrPrologue();
  }
  
  
  void LCodeGen::DoForInPrepareMap(LForInPrepareMap* instr) {
    DCHECK(ToRegister(instr->context()).is(rsi));
  
    DeoptimizeIf(equal, instr, Deoptimizer::kNull);
  
    Condition cc = masm()->CheckSmi(rax);
    DeoptimizeIf(cc, instr, Deoptimizer::kSmi);
  
    STATIC_ASSERT(FIRST_JS_PROXY_TYPE == FIRST_SPEC_OBJECT_TYPE);
    __ CmpObjectType(rax, LAST_JS_PROXY_TYPE, rcx);
    DeoptimizeIf(below_equal, instr, Deoptimizer::kWrongInstanceType);
  
    Label use_cache, call_runtime;
    Register null_value = rdi;
    __ LoadRoot(null_value, Heap::kNullValueRootIndex);
    __ CheckEnumCache(null_value, &call_runtime);
  
    __ movp(rax, FieldOperand(rax, HeapObject::kMapOffset));
    __ jmp(&use_cache, Label::kNear);
  
    // Get the set of properties to enumerate.
    __ bind(&call_runtime);
    __ Push(rax);
    CallRuntime(Runtime::kGetPropertyNamesFast, 1, instr);
  
    __ CompareRoot(FieldOperand(rax, HeapObject::kMapOffset),
                   Heap::kMetaMapRootIndex);
    DeoptimizeIf(not_equal, instr, Deoptimizer::kWrongMap);
    __ bind(&use_cache);
  }
  
  
  void LCodeGen::DoForInCacheArray(LForInCacheArray* instr) {
    Register map = ToRegister(instr->map());
    Register result = ToRegister(instr->result());
    Label load_cache, done;
    __ EnumLength(result, map);
    __ Cmp(result, Smi::FromInt(0));
    __ j(not_equal, &load_cache, Label::kNear);
    __ LoadRoot(result, Heap::kEmptyFixedArrayRootIndex);
    __ jmp(&done, Label::kNear);
    __ bind(&load_cache);
    __ LoadInstanceDescriptors(map, result);
    __ movp(result,
            FieldOperand(result, DescriptorArray::kEnumCacheOffset));
    __ movp(result,
            FieldOperand(result, FixedArray::SizeFor(instr->idx())));
    __ bind(&done);
    Condition cc = masm()->CheckSmi(result);
    DeoptimizeIf(cc, instr, Deoptimizer::kNoCache);
  }
  
  
  void LCodeGen::DoCheckMapValue(LCheckMapValue* instr) {
    Register object = ToRegister(instr->value());
    __ cmpp(ToRegister(instr->map()),
            FieldOperand(object, HeapObject::kMapOffset));
    DeoptimizeIf(not_equal, instr, Deoptimizer::kWrongMap);
  }
  
  
  void LCodeGen::DoDeferredLoadMutableDouble(LLoadFieldByIndex* instr,
                                             Register object,
                                             Register index) {
    PushSafepointRegistersScope scope(this);
    __ Push(object);
    __ Push(index);
    __ xorp(rsi, rsi);
    __ CallRuntimeSaveDoubles(Runtime::kLoadMutableDouble);
    RecordSafepointWithRegisters(
        instr->pointer_map(), 2, Safepoint::kNoLazyDeopt);
    __ StoreToSafepointRegisterSlot(object, rax);
  }
  
  
  void LCodeGen::DoLoadFieldByIndex(LLoadFieldByIndex* instr) {
    class DeferredLoadMutableDouble final : public LDeferredCode {
     public:
      DeferredLoadMutableDouble(LCodeGen* codegen,
                                LLoadFieldByIndex* instr,
                                Register object,
                                Register index)
          : LDeferredCode(codegen),
            instr_(instr),
            object_(object),
            index_(index) {
      }
      void Generate() override {
        codegen()->DoDeferredLoadMutableDouble(instr_, object_, index_);
      }
      LInstruction* instr() override { return instr_; }
  
     private:
      LLoadFieldByIndex* instr_;
      Register object_;
      Register index_;
    };
  
    Register object = ToRegister(instr->object());
    Register index = ToRegister(instr->index());
  
    DeferredLoadMutableDouble* deferred;
    deferred = new(zone()) DeferredLoadMutableDouble(this, instr, object, index);
  
    Label out_of_object, done;
    __ Move(kScratchRegister, Smi::FromInt(1));
    __ testp(index, kScratchRegister);
    __ j(not_zero, deferred->entry());
  
    __ sarp(index, Immediate(1));
  
    __ SmiToInteger32(index, index);
    __ cmpl(index, Immediate(0));
    __ j(less, &out_of_object, Label::kNear);
    __ movp(object, FieldOperand(object,
                                 index,
                                 times_pointer_size,
                                 JSObject::kHeaderSize));
    __ jmp(&done, Label::kNear);
  
    __ bind(&out_of_object);
    __ movp(object, FieldOperand(object, JSObject::kPropertiesOffset));
    __ negl(index);
    // Index is now equal to out of object property index plus 1.
    __ movp(object, FieldOperand(object,
                                 index,
                                 times_pointer_size,
                                 FixedArray::kHeaderSize - kPointerSize));
    __ bind(deferred->exit());
    __ bind(&done);
  }
  
  
  void LCodeGen::DoStoreFrameContext(LStoreFrameContext* instr) {
    Register context = ToRegister(instr->context());
    __ movp(Operand(rbp, StandardFrameConstants::kContextOffset), context);
  }
  
  
  void LCodeGen::DoAllocateBlockContext(LAllocateBlockContext* instr) {
    Handle<ScopeInfo> scope_info = instr->scope_info();
    __ Push(scope_info);
    __ Push(ToRegister(instr->function()));
    CallRuntime(Runtime::kPushBlockContext, 2, instr);
    RecordSafepoint(Safepoint::kNoLazyDeopt);
  }
  
  
  #undef __
  
  } }  // namespace v8::internal
  
  #endif  // V8_TARGET_ARCH_X64
  