diff --git a/src/ic/x64/handler-compiler-x64.cc b/src/ic/x64/handler-compiler-x64.cc
index c4d6ecf..46fa8cc 100644
--- a/src/ic/x64/handler-compiler-x64.cc
+++ b/src/ic/x64/handler-compiler-x64.cc
@@ -15,6 +15,28 @@
 
 #define __ ACCESS_MASM(masm)
 
+void PropertyHandlerCompiler::PushVectorAndSlot(Register vector,
+                                                Register slot) {
+  MacroAssembler* masm = this->masm();
+  __ Push(vector);
+  __ Push(slot);
+}
+
+
+void PropertyHandlerCompiler::PopVectorAndSlot(Register vector, Register slot) {
+  MacroAssembler* masm = this->masm();
+  __ Pop(slot);
+  __ Pop(vector);
+}
+
+
+void PropertyHandlerCompiler::DiscardVectorAndSlot() {
+  MacroAssembler* masm = this->masm();
+  // Remove vector and slot.
+  __ addp(rsp, Immediate(2 * kPointerSize));
+}
+
+
 void PropertyHandlerCompiler::GenerateDictionaryNegativeLookup(
     MacroAssembler* masm, Label* miss_label, Register receiver,
     Handle<Name> name, Register scratch0, Register scratch1) {
@@ -56,24 +78,16 @@
 
 
 void NamedLoadHandlerCompiler::GenerateDirectLoadGlobalFunctionPrototype(
-    MacroAssembler* masm, int index, Register prototype, Label* miss) {
-  Isolate* isolate = masm->isolate();
-  // Get the global function with the given index.
-  Handle<JSFunction> function(
-      JSFunction::cast(isolate->native_context()->get(index)));
-
-  // Check we're still in the same context.
-  Register scratch = prototype;
+    MacroAssembler* masm, int index, Register result, Label* miss) {
   const int offset = Context::SlotOffset(Context::GLOBAL_OBJECT_INDEX);
-  __ movp(scratch, Operand(rsi, offset));
-  __ movp(scratch, FieldOperand(scratch, GlobalObject::kNativeContextOffset));
-  __ Cmp(Operand(scratch, Context::SlotOffset(index)), function);
-  __ j(not_equal, miss);
-
+  __ movp(result, Operand(rsi, offset));
+  __ movp(result, FieldOperand(result, GlobalObject::kNativeContextOffset));
+  __ movp(result, Operand(result, Context::SlotOffset(index)));
   // Load its initial map. The global functions all have initial maps.
-  __ Move(prototype, Handle<Map>(function->initial_map()));
+  __ movp(result,
+          FieldOperand(result, JSFunction::kPrototypeOrInitialMapOffset));
   // Load the prototype from the initial map.
-  __ movp(prototype, FieldOperand(prototype, Map::kPrototypeOffset));
+  __ movp(result, FieldOperand(result, Map::kPrototypeOffset));
 }
 
 
@@ -324,169 +338,60 @@
 }
 
 
-// Receiver_reg is preserved on jumps to miss_label, but may be destroyed if
-// store is successful.
-void NamedStoreHandlerCompiler::GenerateStoreTransition(
-    Handle<Map> transition, Handle<Name> name, Register receiver_reg,
-    Register storage_reg, Register value_reg, Register scratch1,
-    Register scratch2, Register unused, Label* miss_label, Label* slow) {
-  int descriptor = transition->LastAdded();
-  DescriptorArray* descriptors = transition->instance_descriptors();
-  PropertyDetails details = descriptors->GetDetails(descriptor);
-  Representation representation = details.representation();
-  DCHECK(!representation.IsNone());
-
-  if (details.type() == CONSTANT) {
-    Handle<Object> constant(descriptors->GetValue(descriptor), isolate());
-    __ Cmp(value_reg, constant);
-    __ j(not_equal, miss_label);
-  } else if (representation.IsSmi()) {
-    __ JumpIfNotSmi(value_reg, miss_label);
-  } else if (representation.IsHeapObject()) {
-    __ JumpIfSmi(value_reg, miss_label);
-    HeapType* field_type = descriptors->GetFieldType(descriptor);
-    HeapType::Iterator<Map> it = field_type->Classes();
-    if (!it.Done()) {
-      Label do_store;
-      while (true) {
-        __ CompareMap(value_reg, it.Current());
-        it.Advance();
-        if (it.Done()) {
-          __ j(not_equal, miss_label);
-          break;
-        }
-        __ j(equal, &do_store, Label::kNear);
-      }
-      __ bind(&do_store);
-    }
-  } else if (representation.IsDouble()) {
-    Label do_store, heap_number;
-    __ AllocateHeapNumber(storage_reg, scratch1, slow, MUTABLE);
-
-    __ JumpIfNotSmi(value_reg, &heap_number);
-    __ SmiToInteger32(scratch1, value_reg);
-    __ Cvtlsi2sd(xmm0, scratch1);
-    __ jmp(&do_store);
-
-    __ bind(&heap_number);
-    __ CheckMap(value_reg, isolate()->factory()->heap_number_map(), miss_label,
-                DONT_DO_SMI_CHECK);
-    __ movsd(xmm0, FieldOperand(value_reg, HeapNumber::kValueOffset));
-
-    __ bind(&do_store);
-    __ movsd(FieldOperand(storage_reg, HeapNumber::kValueOffset), xmm0);
-  }
-
-  // Stub never generated for objects that require access checks.
-  DCHECK(!transition->is_access_check_needed());
-
-  // Perform map transition for the receiver if necessary.
-  if (details.type() == FIELD &&
-      Map::cast(transition->GetBackPointer())->unused_property_fields() == 0) {
-    // The properties must be extended before we can store the value.
-    // We jump to a runtime call that extends the properties array.
-    __ PopReturnAddressTo(scratch1);
-    __ Push(receiver_reg);
-    __ Push(transition);
-    __ Push(value_reg);
-    __ PushReturnAddressFrom(scratch1);
-    __ TailCallExternalReference(
-        ExternalReference(IC_Utility(IC::kSharedStoreIC_ExtendStorage),
-                          isolate()),
-        3, 1);
-    return;
-  }
-
-  // Update the map of the object.
-  __ Move(scratch1, transition);
-  __ movp(FieldOperand(receiver_reg, HeapObject::kMapOffset), scratch1);
-
-  // Update the write barrier for the map field.
-  __ RecordWriteField(receiver_reg, HeapObject::kMapOffset, scratch1, scratch2,
-                      kDontSaveFPRegs, OMIT_REMEMBERED_SET, OMIT_SMI_CHECK);
-
-  if (details.type() == CONSTANT) {
-    DCHECK(value_reg.is(rax));
-    __ ret(0);
-    return;
-  }
-
-  int index = transition->instance_descriptors()->GetFieldIndex(
-      transition->LastAdded());
-
-  // Adjust for the number of properties stored in the object. Even in the
-  // face of a transition we can use the old map here because the size of the
-  // object and the number of in-object properties is not going to change.
-  index -= transition->inobject_properties();
-
-  // TODO(verwaest): Share this code as a code stub.
-  SmiCheck smi_check =
-      representation.IsTagged() ? INLINE_SMI_CHECK : OMIT_SMI_CHECK;
-  if (index < 0) {
-    // Set the property straight into the object.
-    int offset = transition->instance_size() + (index * kPointerSize);
-    if (representation.IsDouble()) {
-      __ movp(FieldOperand(receiver_reg, offset), storage_reg);
-    } else {
-      __ movp(FieldOperand(receiver_reg, offset), value_reg);
-    }
-
-    if (!representation.IsSmi()) {
-      // Update the write barrier for the array address.
-      if (!representation.IsDouble()) {
-        __ movp(storage_reg, value_reg);
-      }
-      __ RecordWriteField(receiver_reg, offset, storage_reg, scratch1,
-                          kDontSaveFPRegs, EMIT_REMEMBERED_SET, smi_check);
-    }
-  } else {
-    // Write to the properties array.
-    int offset = index * kPointerSize + FixedArray::kHeaderSize;
-    // Get the properties array (optimistically).
-    __ movp(scratch1, FieldOperand(receiver_reg, JSObject::kPropertiesOffset));
-    if (representation.IsDouble()) {
-      __ movp(FieldOperand(scratch1, offset), storage_reg);
-    } else {
-      __ movp(FieldOperand(scratch1, offset), value_reg);
-    }
-
-    if (!representation.IsSmi()) {
-      // Update the write barrier for the array address.
-      if (!representation.IsDouble()) {
-        __ movp(storage_reg, value_reg);
-      }
-      __ RecordWriteField(scratch1, offset, storage_reg, receiver_reg,
-                          kDontSaveFPRegs, EMIT_REMEMBERED_SET, smi_check);
-    }
-  }
-
-  // Return the value (register rax).
-  DCHECK(value_reg.is(rax));
-  __ ret(0);
+void NamedStoreHandlerCompiler::GenerateRestoreName(Handle<Name> name) {
+  __ Move(this->name(), name);
 }
 
 
-void NamedStoreHandlerCompiler::GenerateStoreField(LookupIterator* lookup,
-                                                   Register value_reg,
-                                                   Label* miss_label) {
-  DCHECK(lookup->representation().IsHeapObject());
-  __ JumpIfSmi(value_reg, miss_label);
-  HeapType::Iterator<Map> it = lookup->GetFieldType()->Classes();
-  Label do_store;
-  while (true) {
-    __ CompareMap(value_reg, it.Current());
-    it.Advance();
-    if (it.Done()) {
-      __ j(not_equal, miss_label);
-      break;
-    }
-    __ j(equal, &do_store, Label::kNear);
+void NamedStoreHandlerCompiler::GenerateRestoreMap(Handle<Map> transition,
+                                                   Register scratch,
+                                                   Label* miss) {
+  Handle<WeakCell> cell = Map::WeakCellForMap(transition);
+  Register map_reg = StoreTransitionDescriptor::MapRegister();
+  DCHECK(!map_reg.is(scratch));
+  __ LoadWeakValue(map_reg, cell, miss);
+  if (transition->CanBeDeprecated()) {
+    __ movl(scratch, FieldOperand(map_reg, Map::kBitField3Offset));
+    __ andl(scratch, Immediate(Map::Deprecated::kMask));
+    __ j(not_zero, miss);
   }
-  __ bind(&do_store);
+}
 
-  StoreFieldStub stub(isolate(), lookup->GetFieldIndex(),
-                      lookup->representation());
-  GenerateTailCall(masm(), stub.GetCode());
+
+void NamedStoreHandlerCompiler::GenerateConstantCheck(Register map_reg,
+                                                      int descriptor,
+                                                      Register value_reg,
+                                                      Register scratch,
+                                                      Label* miss_label) {
+  DCHECK(!map_reg.is(scratch));
+  DCHECK(!map_reg.is(value_reg));
+  DCHECK(!value_reg.is(scratch));
+  __ LoadInstanceDescriptors(map_reg, scratch);
+  __ movp(scratch,
+          FieldOperand(scratch, DescriptorArray::GetValueOffset(descriptor)));
+  __ cmpp(value_reg, scratch);
+  __ j(not_equal, miss_label);
+}
+
+
+void NamedStoreHandlerCompiler::GenerateFieldTypeChecks(HeapType* field_type,
+                                                        Register value_reg,
+                                                        Label* miss_label) {
+  __ JumpIfSmi(value_reg, miss_label);
+  HeapType::Iterator<Map> it = field_type->Classes();
+  if (!it.Done()) {
+    Label do_store;
+    while (true) {
+      __ CompareMap(value_reg, it.Current());
+      it.Advance();
+      if (it.Done()) {
+        __ j(not_equal, miss_label);
+        break;
+      }
+      __ j(equal, &do_store, Label::kNear);
+    }
+    __ bind(&do_store);
+  }
 }
 
 
@@ -543,18 +448,13 @@
       reg = holder_reg;  // From now on the object will be in holder_reg.
       __ movp(reg, FieldOperand(scratch1, Map::kPrototypeOffset));
     } else {
-      bool in_new_space = heap()->InNewSpace(*prototype);
-      // Two possible reasons for loading the prototype from the map:
-      // (1) Can't store references to new space in code.
-      // (2) Handler is shared for all receivers with the same prototype
-      //     map (but not necessarily the same prototype instance).
-      bool load_prototype_from_map = in_new_space || depth == 1;
-      if (load_prototype_from_map) {
-        // Save the map in scratch1 for later.
-        __ movp(scratch1, FieldOperand(reg, HeapObject::kMapOffset));
-      }
+      Register map_reg = scratch1;
+      __ movp(map_reg, FieldOperand(reg, HeapObject::kMapOffset));
+
       if (depth != 1 || check == CHECK_ALL_MAPS) {
-        __ CheckMap(reg, current_map, miss, DONT_DO_SMI_CHECK);
+        Handle<WeakCell> cell = Map::WeakCellForMap(current_map);
+        __ CmpWeakValue(map_reg, cell, scratch2);
+        __ j(not_equal, miss);
       }
 
       // Check access rights to the global object.  This has to happen after
@@ -571,11 +471,7 @@
       }
       reg = holder_reg;  // From now on the object will be in holder_reg.
 
-      if (load_prototype_from_map) {
-        __ movp(reg, FieldOperand(scratch1, Map::kPrototypeOffset));
-      } else {
-        __ Move(reg, prototype);
-      }
+      __ movp(reg, FieldOperand(map_reg, Map::kPrototypeOffset));
     }
 
     // Go to the next object in the prototype chain.
@@ -587,8 +483,10 @@
   LOG(isolate(), IntEvent("check-maps-depth", depth + 1));
 
   if (depth != 0 || check == CHECK_ALL_MAPS) {
-    // Check the holder map.
-    __ CheckMap(reg, current_map, miss, DONT_DO_SMI_CHECK);
+    __ movp(scratch1, FieldOperand(reg, HeapObject::kMapOffset));
+    Handle<WeakCell> cell = Map::WeakCellForMap(current_map);
+    __ CmpWeakValue(scratch1, cell, scratch2);
+    __ j(not_equal, miss);
   }
 
   // Perform security check for access to the global object.
@@ -608,6 +506,10 @@
     Label success;
     __ jmp(&success);
     __ bind(miss);
+    if (IC::ICUseVector(kind())) {
+      DCHECK(kind() == Code::LOAD_IC);
+      PopVectorAndSlot();
+    }
     TailCallBuiltin(masm(), MissBuiltin(kind()));
     __ bind(&success);
   }
@@ -706,6 +608,7 @@
     }
     __ Push(holder_reg);
     __ Push(this->name());
+    InterceptorVectorSlotPush(holder_reg);
 
     // Invoke an interceptor.  Note: map checks from receiver to
     // interceptor's holder has been compiled before (see a caller
@@ -723,6 +626,7 @@
     __ ret(0);
 
     __ bind(&interceptor_failed);
+    InterceptorVectorSlotPop(holder_reg);
     __ Pop(this->name());
     __ Pop(holder_reg);
     if (must_preserve_receiver_reg) {
@@ -755,7 +659,7 @@
 Handle<Code> NamedStoreHandlerCompiler::CompileStoreCallback(
     Handle<JSObject> object, Handle<Name> name,
     Handle<ExecutableAccessorInfo> callback) {
-  Register holder_reg = Frontend(receiver(), name);
+  Register holder_reg = Frontend(name);
 
   __ PopReturnAddressTo(scratch1());
   __ Push(receiver());
@@ -801,11 +705,15 @@
 Handle<Code> NamedLoadHandlerCompiler::CompileLoadGlobal(
     Handle<PropertyCell> cell, Handle<Name> name, bool is_configurable) {
   Label miss;
+  if (IC::ICUseVector(kind())) {
+    PushVectorAndSlot();
+  }
   FrontendHeader(receiver(), name, &miss);
 
   // Get the value from the cell.
   Register result = StoreDescriptor::ValueRegister();
-  __ Move(result, cell);
+  Handle<WeakCell> weak_cell = factory()->NewWeakCell(cell);
+  __ LoadWeakValue(result, weak_cell, &miss);
   __ movp(result, FieldOperand(result, PropertyCell::kValueOffset));
 
   // Check for deleted property if property can actually be deleted.
@@ -819,6 +727,9 @@
 
   Counters* counters = isolate()->counters();
   __ IncrementCounter(counters->named_load_global_stub(), 1);
+  if (IC::ICUseVector(kind())) {
+    DiscardVectorAndSlot();
+  }
   __ ret(0);
 
   FrontendFooter(name, &miss);
diff --git a/src/ic/x64/ic-compiler-x64.cc b/src/ic/x64/ic-compiler-x64.cc
index a5848b6..5be9c46 100644
--- a/src/ic/x64/ic-compiler-x64.cc
+++ b/src/ic/x64/ic-compiler-x64.cc
@@ -42,20 +42,22 @@
     MapHandleList* receiver_maps, CodeHandleList* handler_stubs,
     MapHandleList* transitioned_maps) {
   Label miss;
-  __ JumpIfSmi(receiver(), &miss, Label::kNear);
+  __ JumpIfSmi(receiver(), &miss);
 
-  __ movp(scratch1(), FieldOperand(receiver(), HeapObject::kMapOffset));
+  Register map_reg = scratch1();
+  __ movp(map_reg, FieldOperand(receiver(), HeapObject::kMapOffset));
   int receiver_count = receiver_maps->length();
   for (int i = 0; i < receiver_count; ++i) {
+    Handle<WeakCell> cell = Map::WeakCellForMap(receiver_maps->at(i));
     // Check map and tail call if there's a match
-    __ Cmp(scratch1(), receiver_maps->at(i));
+    __ CmpWeakValue(map_reg, cell, scratch2());
     if (transitioned_maps->at(i).is_null()) {
       __ j(equal, handler_stubs->at(i), RelocInfo::CODE_TARGET);
     } else {
       Label next_map;
       __ j(not_equal, &next_map, Label::kNear);
-      __ Move(transition_map(), transitioned_maps->at(i),
-              RelocInfo::EMBEDDED_OBJECT);
+      Handle<WeakCell> cell = Map::WeakCellForMap(transitioned_maps->at(i));
+      __ LoadWeakValue(transition_map(), cell, &miss);
       __ jmp(handler_stubs->at(i), RelocInfo::CODE_TARGET);
       __ bind(&next_map);
     }
@@ -79,9 +81,12 @@
 
   if (check == PROPERTY &&
       (kind() == Code::KEYED_LOAD_IC || kind() == Code::KEYED_STORE_IC)) {
-    // In case we are compiling an IC for dictionary loads and stores, just
+    // In case we are compiling an IC for dictionary loads or stores, just
     // check whether the name is unique.
     if (name.is_identical_to(isolate()->factory()->normal_ic_symbol())) {
+      // Keyed loads with dictionaries shouldn't be here, they go generic.
+      // The DCHECK is to protect assumptions when --vector-ics is on.
+      DCHECK(kind() != Code::KEYED_LOAD_IC);
       Register tmp = scratch1();
       __ JumpIfSmi(this->name(), &miss);
       __ movp(tmp, FieldOperand(this->name(), HeapObject::kMapOffset));
@@ -109,8 +114,9 @@
     Handle<Map> map = IC::TypeToMap(*type, isolate());
     if (!map->is_deprecated()) {
       number_of_handled_maps++;
+      Handle<WeakCell> cell = Map::WeakCellForMap(map);
       // Check map and tail call if there's a match
-      __ Cmp(map_reg, map);
+      __ CmpWeakValue(map_reg, cell, scratch2());
       if (type->Is(HeapType::Number())) {
         DCHECK(!number_case.is_unused());
         __ bind(&number_case);
diff --git a/src/ic/x64/ic-x64.cc b/src/ic/x64/ic-x64.cc
index ad79f30..2709a85 100644
--- a/src/ic/x64/ic-x64.cc
+++ b/src/ic/x64/ic-x64.cc
@@ -119,9 +119,8 @@
       NameDictionary::kElementsStartIndex * kPointerSize;
   const int kDetailsOffset = kElementsStartOffset + 2 * kPointerSize;
   const int kTypeAndReadOnlyMask =
-      (PropertyDetails::TypeField::kMask |
-       PropertyDetails::AttributesField::encode(READ_ONLY))
-      << kSmiTagSize;
+      PropertyDetails::TypeField::kMask |
+      PropertyDetails::AttributesField::encode(READ_ONLY);
   __ Test(Operand(elements, scratch1, times_pointer_size,
                   kDetailsOffset - kHeapObjectTag),
           Smi::FromInt(kTypeAndReadOnlyMask));
@@ -403,33 +402,7 @@
 }
 
 
-void KeyedLoadIC::GenerateString(MacroAssembler* masm) {
-  // Return address is on the stack.
-  Label miss;
-
-  Register receiver = LoadDescriptor::ReceiverRegister();
-  Register index = LoadDescriptor::NameRegister();
-  Register scratch = rbx;
-  Register result = rax;
-  DCHECK(!scratch.is(receiver) && !scratch.is(index));
-
-  StringCharAtGenerator char_at_generator(receiver, index, scratch, result,
-                                          &miss,  // When not a string.
-                                          &miss,  // When not a number.
-                                          &miss,  // When index out of range.
-                                          STRING_INDEX_IS_ARRAY_INDEX);
-  char_at_generator.GenerateFast(masm);
-  __ ret(0);
-
-  StubRuntimeCallHelper call_helper;
-  char_at_generator.GenerateSlow(masm, call_helper);
-
-  __ bind(&miss);
-  GenerateMiss(masm);
-}
-
-
-static void KeyedStoreGenerateGenericHelper(
+static void KeyedStoreGenerateMegamorphicHelper(
     MacroAssembler* masm, Label* fast_object, Label* fast_double, Label* slow,
     KeyedStoreCheckMap check_map, KeyedStoreIncrementLength increment_length) {
   Label transition_smi_elements;
@@ -566,12 +539,12 @@
 }
 
 
-void KeyedStoreIC::GenerateGeneric(MacroAssembler* masm,
-                                   StrictMode strict_mode) {
+void KeyedStoreIC::GenerateMegamorphic(MacroAssembler* masm,
+                                       StrictMode strict_mode) {
   // Return address is on the stack.
   Label slow, slow_with_tagged_index, fast_object, fast_object_grow;
   Label fast_double, fast_double_grow;
-  Label array, extra, check_if_double_array;
+  Label array, extra, check_if_double_array, maybe_name_key, miss;
   Register receiver = StoreDescriptor::ReceiverRegister();
   Register key = StoreDescriptor::NameRegister();
   DCHECK(receiver.is(rdx));
@@ -587,7 +560,7 @@
            Immediate(1 << Map::kIsAccessCheckNeeded | 1 << Map::kIsObserved));
   __ j(not_zero, &slow_with_tagged_index);
   // Check that the key is a smi.
-  __ JumpIfNotSmi(key, &slow_with_tagged_index);
+  __ JumpIfNotSmi(key, &maybe_name_key);
   __ SmiToInteger32(key, key);
 
   __ CmpInstanceType(r9, JS_ARRAY_TYPE);
@@ -610,6 +583,17 @@
   PropertyICCompiler::GenerateRuntimeSetProperty(masm, strict_mode);
   // Never returns to here.
 
+  __ bind(&maybe_name_key);
+  __ movp(r9, FieldOperand(key, HeapObject::kMapOffset));
+  __ movzxbp(r9, FieldOperand(r9, Map::kInstanceTypeOffset));
+  __ JumpIfNotUniqueNameInstanceType(r9, &slow_with_tagged_index);
+  Code::Flags flags = Code::RemoveTypeAndHolderFromFlags(
+      Code::ComputeHandlerFlags(Code::STORE_IC));
+  masm->isolate()->stub_cache()->GenerateProbe(
+      masm, Code::STORE_IC, flags, false, receiver, key, rbx, no_reg);
+  // Cache miss.
+  __ jmp(&miss);
+
   // Extra capacity case: Check if there is extra capacity to
   // perform the store and update the length. Used for adding one
   // element to the array by writing to array[array.length].
@@ -644,10 +628,14 @@
   __ SmiCompareInteger32(FieldOperand(receiver, JSArray::kLengthOffset), key);
   __ j(below_equal, &extra);
 
-  KeyedStoreGenerateGenericHelper(masm, &fast_object, &fast_double, &slow,
-                                  kCheckMap, kDontIncrementLength);
-  KeyedStoreGenerateGenericHelper(masm, &fast_object_grow, &fast_double_grow,
-                                  &slow, kDontCheckMap, kIncrementLength);
+  KeyedStoreGenerateMegamorphicHelper(masm, &fast_object, &fast_double, &slow,
+                                      kCheckMap, kDontIncrementLength);
+  KeyedStoreGenerateMegamorphicHelper(masm, &fast_object_grow,
+                                      &fast_double_grow, &slow, kDontCheckMap,
+                                      kIncrementLength);
+
+  __ bind(&miss);
+  GenerateMiss(masm);
 }
 
 
@@ -774,11 +762,30 @@
 }
 
 
-// A register that isn't one of the parameters to the load ic.
-static const Register LoadIC_TempRegister() { return rbx; }
+static void LoadIC_PushArgs(MacroAssembler* masm) {
+  Register receiver = LoadDescriptor::ReceiverRegister();
+  Register name = LoadDescriptor::NameRegister();
+  if (FLAG_vector_ics) {
+    Register slot = VectorLoadICDescriptor::SlotRegister();
+    Register vector = VectorLoadICDescriptor::VectorRegister();
+    DCHECK(!rdi.is(receiver) && !rdi.is(name) && !rdi.is(slot) &&
+           !rdi.is(vector));
 
+    __ PopReturnAddressTo(rdi);
+    __ Push(receiver);
+    __ Push(name);
+    __ Push(slot);
+    __ Push(vector);
+    __ PushReturnAddressFrom(rdi);
+  } else {
+    DCHECK(!rbx.is(receiver) && !rbx.is(name));
 
-static const Register KeyedLoadIC_TempRegister() { return rbx; }
+    __ PopReturnAddressTo(rbx);
+    __ Push(receiver);
+    __ Push(name);
+    __ PushReturnAddressFrom(rbx);
+  }
+}
 
 
 void LoadIC::GenerateMiss(MacroAssembler* masm) {
@@ -787,25 +794,26 @@
   Counters* counters = masm->isolate()->counters();
   __ IncrementCounter(counters->load_miss(), 1);
 
-  __ PopReturnAddressTo(LoadIC_TempRegister());
-  __ Push(LoadDescriptor::ReceiverRegister());  // receiver
-  __ Push(LoadDescriptor::NameRegister());      // name
-  __ PushReturnAddressFrom(LoadIC_TempRegister());
+  LoadIC_PushArgs(masm);
 
   // Perform tail call to the entry.
   ExternalReference ref =
       ExternalReference(IC_Utility(kLoadIC_Miss), masm->isolate());
-  __ TailCallExternalReference(ref, 2, 1);
+  int arg_count = FLAG_vector_ics ? 4 : 2;
+  __ TailCallExternalReference(ref, arg_count, 1);
 }
 
 
 void LoadIC::GenerateRuntimeGetProperty(MacroAssembler* masm) {
   // The return address is on the stack.
+  Register receiver = LoadDescriptor::ReceiverRegister();
+  Register name = LoadDescriptor::NameRegister();
+  DCHECK(!rbx.is(receiver) && !rbx.is(name));
 
-  __ PopReturnAddressTo(LoadIC_TempRegister());
-  __ Push(LoadDescriptor::ReceiverRegister());  // receiver
-  __ Push(LoadDescriptor::NameRegister());      // name
-  __ PushReturnAddressFrom(LoadIC_TempRegister());
+  __ PopReturnAddressTo(rbx);
+  __ Push(receiver);
+  __ Push(name);
+  __ PushReturnAddressFrom(rbx);
 
   // Perform tail call to the entry.
   __ TailCallRuntime(Runtime::kGetProperty, 2, 1);
@@ -817,25 +825,26 @@
   Counters* counters = masm->isolate()->counters();
   __ IncrementCounter(counters->keyed_load_miss(), 1);
 
-  __ PopReturnAddressTo(KeyedLoadIC_TempRegister());
-  __ Push(LoadDescriptor::ReceiverRegister());  // receiver
-  __ Push(LoadDescriptor::NameRegister());      // name
-  __ PushReturnAddressFrom(KeyedLoadIC_TempRegister());
+  LoadIC_PushArgs(masm);
 
   // Perform tail call to the entry.
   ExternalReference ref =
       ExternalReference(IC_Utility(kKeyedLoadIC_Miss), masm->isolate());
-  __ TailCallExternalReference(ref, 2, 1);
+  int arg_count = FLAG_vector_ics ? 4 : 2;
+  __ TailCallExternalReference(ref, arg_count, 1);
 }
 
 
 void KeyedLoadIC::GenerateRuntimeGetProperty(MacroAssembler* masm) {
   // The return address is on the stack.
+  Register receiver = LoadDescriptor::ReceiverRegister();
+  Register name = LoadDescriptor::NameRegister();
+  DCHECK(!rbx.is(receiver) && !rbx.is(name));
 
-  __ PopReturnAddressTo(KeyedLoadIC_TempRegister());
-  __ Push(LoadDescriptor::ReceiverRegister());  // receiver
-  __ Push(LoadDescriptor::NameRegister());      // name
-  __ PushReturnAddressFrom(KeyedLoadIC_TempRegister());
+  __ PopReturnAddressTo(rbx);
+  __ Push(receiver);
+  __ Push(name);
+  __ PushReturnAddressFrom(rbx);
 
   // Perform tail call to the entry.
   __ TailCallRuntime(Runtime::kKeyedGetProperty, 2, 1);
@@ -849,7 +858,7 @@
   Code::Flags flags = Code::RemoveTypeAndHolderFromFlags(
       Code::ComputeHandlerFlags(Code::STORE_IC));
   masm->isolate()->stub_cache()->GenerateProbe(
-      masm, flags, false, StoreDescriptor::ReceiverRegister(),
+      masm, Code::STORE_IC, flags, false, StoreDescriptor::ReceiverRegister(),
       StoreDescriptor::NameRegister(), rbx, no_reg);
 
   // Cache miss: Jump to runtime.
diff --git a/src/ic/x64/stub-cache-x64.cc b/src/ic/x64/stub-cache-x64.cc
index a54ddca..f15635c 100644
--- a/src/ic/x64/stub-cache-x64.cc
+++ b/src/ic/x64/stub-cache-x64.cc
@@ -7,7 +7,9 @@
 #if V8_TARGET_ARCH_X64
 
 #include "src/codegen.h"
+#include "src/ic/ic.h"
 #include "src/ic/stub-cache.h"
+#include "src/interface-descriptors.h"
 
 namespace v8 {
 namespace internal {
@@ -16,7 +18,7 @@
 
 
 static void ProbeTable(Isolate* isolate, MacroAssembler* masm,
-                       Code::Flags flags, bool leave_frame,
+                       Code::Kind ic_kind, Code::Flags flags, bool leave_frame,
                        StubCache::Table table, Register receiver, Register name,
                        // The offset is scaled by 4, based on
                        // kCacheIndexShift, which is two bits
@@ -41,14 +43,14 @@
   __ LoadAddress(kScratchRegister, key_offset);
 
   // Check that the key in the entry matches the name.
-  // Multiply entry offset by 16 to get the entry address. Since the
-  // offset register already holds the entry offset times four, multiply
-  // by a further four.
-  __ cmpl(name, Operand(kScratchRegister, offset, scale_factor, 0));
+  __ cmpp(name, Operand(kScratchRegister, offset, scale_factor, 0));
   __ j(not_equal, &miss);
 
   // Get the map entry from the cache.
   // Use key_offset + kPointerSize * 2, rather than loading map_offset.
+  DCHECK(isolate->stub_cache()->map_reference(table).address() -
+             isolate->stub_cache()->key_reference(table).address() ==
+         kPointerSize * 2);
   __ movp(kScratchRegister,
           Operand(kScratchRegister, offset, scale_factor, kPointerSize * 2));
   __ cmpp(kScratchRegister, FieldOperand(receiver, HeapObject::kMapOffset));
@@ -82,10 +84,11 @@
 }
 
 
-void StubCache::GenerateProbe(MacroAssembler* masm, Code::Flags flags,
-                              bool leave_frame, Register receiver,
-                              Register name, Register scratch, Register extra,
-                              Register extra2, Register extra3) {
+void StubCache::GenerateProbe(MacroAssembler* masm, Code::Kind ic_kind,
+                              Code::Flags flags, bool leave_frame,
+                              Register receiver, Register name,
+                              Register scratch, Register extra, Register extra2,
+                              Register extra3) {
   Isolate* isolate = masm->isolate();
   Label miss;
   USE(extra);   // The register extra is not used on the X64 platform.
@@ -107,6 +110,17 @@
   DCHECK(extra2.is(no_reg));
   DCHECK(extra3.is(no_reg));
 
+#ifdef DEBUG
+  // If vector-based ics are in use, ensure that scratch doesn't conflict with
+  // the vector and slot registers, which need to be preserved for a handler
+  // call or miss.
+  if (IC::ICUseVector(ic_kind)) {
+    Register vector = VectorLoadICDescriptor::VectorRegister();
+    Register slot = VectorLoadICDescriptor::SlotRegister();
+    DCHECK(!AreAliased(vector, slot, scratch));
+  }
+#endif
+
   Counters* counters = masm->isolate()->counters();
   __ IncrementCounter(counters->megamorphic_stub_cache_probes(), 1);
 
@@ -123,8 +137,8 @@
   __ andp(scratch, Immediate((kPrimaryTableSize - 1) << kCacheIndexShift));
 
   // Probe the primary table.
-  ProbeTable(isolate, masm, flags, leave_frame, kPrimary, receiver, name,
-             scratch);
+  ProbeTable(isolate, masm, ic_kind, flags, leave_frame, kPrimary, receiver,
+             name, scratch);
 
   // Primary miss: Compute hash for secondary probe.
   __ movl(scratch, FieldOperand(name, Name::kHashFieldOffset));
@@ -136,8 +150,8 @@
   __ andp(scratch, Immediate((kSecondaryTableSize - 1) << kCacheIndexShift));
 
   // Probe the secondary table.
-  ProbeTable(isolate, masm, flags, leave_frame, kSecondary, receiver, name,
-             scratch);
+  ProbeTable(isolate, masm, ic_kind, flags, leave_frame, kSecondary, receiver,
+             name, scratch);
 
   // Cache miss: Fall-through and let caller handle the miss by
   // entering the runtime system.