[turbofan] Introduce Oddball::to_number_raw and use it for change lowering.

The Oddball::to_number_raw field contains the actual double value of the
Oddball converted to a number, and is located at the same offset as the
HeapNumber::value field, so for lowering changes we don't need to check
for undefined (or any other oddball explicitly).

R=jarin@chromium.org

Review URL: https://codereview.chromium.org/1922443002

Cr-Commit-Position: refs/heads/master@{#35753}

include/v8.h

@@ -7337,7 +7337,7 @@ class Internals {
       1 * kApiPointerSize + kApiIntSize;
   static const int kStringResourceOffset = 3 * kApiPointerSize;
 
-  static const int kOddballKindOffset = 5 * kApiPointerSize;
+  static const int kOddballKindOffset = 5 * kApiPointerSize + sizeof(double);
   static const int kForeignAddressOffset = kApiPointerSize;
   static const int kJSObjectHeaderSize = 3 * kApiPointerSize;
   static const int kFixedArrayHeaderSize = 2 * kApiPointerSize;

src/compiler/change-lowering.cc

@@ -294,29 +294,8 @@ Reduction ChangeLowering::ChangeTaggedToUI32(Node* value, Node* control,
 
   Node* if_not_smi = graph()->NewNode(common()->IfTrue(), branch);
 
-  Node* vnot_smi;
-  if (NodeProperties::GetType(value)->Maybe(Type::Undefined())) {
-    Node* check_undefined = graph()->NewNode(machine()->WordEqual(), value,
-                                             jsgraph()->UndefinedConstant());
-    Node* branch_undefined = graph()->NewNode(
-        common()->Branch(BranchHint::kFalse), check_undefined, if_not_smi);
-
-    Node* if_undefined = graph()->NewNode(common()->IfTrue(), branch_undefined);
-    Node* vundefined = jsgraph()->Int32Constant(0);
-
-    Node* if_not_undefined =
-        graph()->NewNode(common()->IfFalse(), branch_undefined);
-    Node* vheap_number =
-        graph()->NewNode(op, LoadHeapNumberValue(value, if_not_undefined));
-
-    if_not_smi =
-        graph()->NewNode(common()->Merge(2), if_undefined, if_not_undefined);
-    vnot_smi =
-        graph()->NewNode(common()->Phi(MachineRepresentation::kWord32, 2),
-                         vundefined, vheap_number, if_not_smi);
-  } else {
-    vnot_smi = graph()->NewNode(op, LoadHeapNumberValue(value, if_not_smi));
-  }
+  STATIC_ASSERT(HeapNumber::kValueOffset == Oddball::kToNumberRawOffset);
+  Node* vnot_smi = graph()->NewNode(op, LoadHeapNumberValue(value, if_not_smi));
 
   Node* if_smi = graph()->NewNode(common()->IfFalse(), branch);
   Node* vfrom_smi = ChangeSmiToWord32(value);
@@ -336,29 +315,8 @@ Reduction ChangeLowering::ChangeTaggedToFloat64(Node* value, Node* control) {
 
   Node* if_not_smi = graph()->NewNode(common()->IfTrue(), branch);
 
-  Node* vnot_smi;
-  if (NodeProperties::GetType(value)->Maybe(Type::Undefined())) {
-    Node* check_undefined = graph()->NewNode(machine()->WordEqual(), value,
-                                             jsgraph()->UndefinedConstant());
-    Node* branch_undefined = graph()->NewNode(
-        common()->Branch(BranchHint::kFalse), check_undefined, if_not_smi);
-
-    Node* if_undefined = graph()->NewNode(common()->IfTrue(), branch_undefined);
-    Node* vundefined =
-        jsgraph()->Float64Constant(std::numeric_limits<double>::quiet_NaN());
-
-    Node* if_not_undefined =
-        graph()->NewNode(common()->IfFalse(), branch_undefined);
-    Node* vheap_number = LoadHeapNumberValue(value, if_not_undefined);
-
-    if_not_smi =
-        graph()->NewNode(common()->Merge(2), if_undefined, if_not_undefined);
-    vnot_smi =
-        graph()->NewNode(common()->Phi(MachineRepresentation::kFloat64, 2),
-                         vundefined, vheap_number, if_not_smi);
-  } else {
-    vnot_smi = LoadHeapNumberValue(value, if_not_smi);
-  }
+  STATIC_ASSERT(HeapNumber::kValueOffset == Oddball::kToNumberRawOffset);
+  Node* vnot_smi = LoadHeapNumberValue(value, if_not_smi);
 
   Node* if_smi = graph()->NewNode(common()->IfFalse(), branch);
   Node* vfrom_smi = ChangeSmiToFloat64(value);
@@ -399,31 +357,9 @@ Reduction ChangeLowering::TruncateTaggedToWord32(Node* value, Node* control) {
 
   Node* if_not_smi = graph()->NewNode(common()->IfTrue(), branch);
 
-  Node* vnot_smi;
-  if (NodeProperties::GetType(value)->Maybe(Type::Undefined())) {
-    Node* check_undefined = graph()->NewNode(machine()->WordEqual(), value,
-                                             jsgraph()->UndefinedConstant());
-    Node* branch_undefined = graph()->NewNode(
-        common()->Branch(BranchHint::kFalse), check_undefined, if_not_smi);
-
-    Node* if_undefined = graph()->NewNode(common()->IfTrue(), branch_undefined);
-    Node* vundefined = jsgraph()->Int32Constant(0);
-
-    Node* if_not_undefined =
-        graph()->NewNode(common()->IfFalse(), branch_undefined);
-    Node* vheap_number =
-        graph()->NewNode(machine()->TruncateFloat64ToWord32(),
-                         LoadHeapNumberValue(value, if_not_undefined));
-
-    if_not_smi =
-        graph()->NewNode(common()->Merge(2), if_undefined, if_not_undefined);
-    vnot_smi =
-        graph()->NewNode(common()->Phi(MachineRepresentation::kWord32, 2),
-                         vundefined, vheap_number, if_not_smi);
-  } else {
-    vnot_smi = graph()->NewNode(machine()->TruncateFloat64ToWord32(),
-                                LoadHeapNumberValue(value, if_not_smi));
-  }
+  STATIC_ASSERT(HeapNumber::kValueOffset == Oddball::kToNumberRawOffset);
+  Node* vnot_smi = graph()->NewNode(machine()->TruncateFloat64ToWord32(),
+                                    LoadHeapNumberValue(value, if_not_smi));
 
   Node* if_smi = graph()->NewNode(common()->IfFalse(), branch);
   Node* vfrom_smi = ChangeSmiToWord32(value);

src/objects-inl.h

@@ -1909,6 +1909,13 @@ InterceptorInfo* Map::GetIndexedInterceptor() {
       constructor->shared()->get_api_func_data()->indexed_property_handler());
 }
 
+double Oddball::to_number_raw() const {
+  return READ_DOUBLE_FIELD(this, kToNumberRawOffset);
+}
+
+void Oddball::set_to_number_raw(double value) {
+  WRITE_DOUBLE_FIELD(this, kToNumberRawOffset, value);
+}
 
 ACCESSORS(Oddball, to_string, String, kToStringOffset)
 ACCESSORS(Oddball, to_number, Object, kToNumberOffset)

src/objects.cc

@@ -12788,6 +12788,7 @@ void Oddball::Initialize(Isolate* isolate, Handle<Oddball> oddball,
       isolate->factory()->InternalizeUtf8String(to_string);
   Handle<String> internalized_type_of =
       isolate->factory()->InternalizeUtf8String(type_of);
+  oddball->set_to_number_raw(to_number->Number());
   oddball->set_to_boolean(isolate->heap()->ToBoolean(to_boolean));
   oddball->set_to_number(*to_number);
   oddball->set_to_string(*internalized_to_string);

src/objects.h

@@ -9433,6 +9433,10 @@ class VectorIterator {
 // The Oddball describes objects null, undefined, true, and false.
 class Oddball: public HeapObject {
  public:
+  // [to_number_raw]: Cached raw to_number computed at startup.
+  inline double to_number_raw() const;
+  inline void set_to_number_raw(double value);
+
   // [to_string]: Cached to_string computed at startup.
   DECL_ACCESSORS(to_string, String)
 
@@ -9462,7 +9466,8 @@ class Oddball: public HeapObject {
                          bool to_boolean, const char* type_of, byte kind);
 
   // Layout description.
-  static const int kToStringOffset = HeapObject::kHeaderSize;
+  static const int kToNumberRawOffset = HeapObject::kHeaderSize;
+  static const int kToStringOffset = kToNumberRawOffset + kDoubleSize;
   static const int kToNumberOffset = kToStringOffset + kPointerSize;
   static const int kToBooleanOffset = kToNumberOffset + kPointerSize;
   static const int kTypeOfOffset = kToBooleanOffset + kPointerSize;
@@ -9484,6 +9489,7 @@ class Oddball: public HeapObject {
   typedef FixedBodyDescriptor<kToStringOffset, kTypeOfOffset + kPointerSize,
                               kSize> BodyDescriptor;
 
+  STATIC_ASSERT(kToNumberRawOffset == HeapNumber::kValueOffset);
   STATIC_ASSERT(kKindOffset == Internals::kOddballKindOffset);
   STATIC_ASSERT(kNull == Internals::kNullOddballKind);
   STATIC_ASSERT(kUndefined == Internals::kUndefinedOddballKind);