[crankshaft][runtime] Initialize uninitialized double fields with hole NaN value instead of 0.0.

src/crankshaft/hydrogen.cc

Index: src/crankshaft/hydrogen.cc
diff --git a/src/crankshaft/hydrogen.cc b/src/crankshaft/hydrogen.cc
index 959e409500ab66ffe93613f83f68c7d16e3162ec..81b651d32c608c7cbc1a16354fadf57f9efe095c 100644
--- a/src/crankshaft/hydrogen.cc
+++ b/src/crankshaft/hydrogen.cc
@@ -5500,6 +5500,7 @@ void HOptimizedGraphBuilder::VisitObjectLiteral(ObjectLiteral* expr) {
               if (info.CanAccessMonomorphic()) {
                 HValue* checked_literal = Add<HCheckMaps>(literal, map);
                 DCHECK(!info.IsAccessorConstant());
+                info.MarkAsInitializingStore();
                 store = BuildMonomorphicAccess(
                     &info, literal, checked_literal, value,
                     BailoutId::None(), BailoutId::None());
@@ -5741,9 +5742,8 @@ HInstruction* HOptimizedGraphBuilder::BuildStoreNamedField(
     }
 
     // This is a normal store.
-    instr = New<HStoreNamedField>(
-        checked_object->ActualValue(), field_access, value,
-        transition_to_field ? INITIALIZING_STORE : STORE_TO_INITIALIZED_ENTRY);
+    instr = New<HStoreNamedField>(checked_object->ActualValue(), field_access,
+                                  value, info->StoreMode());
   }
 
   if (transition_to_field) {
@@ -5754,6 +5754,17 @@ HInstruction* HOptimizedGraphBuilder::BuildStoreNamedField(
   return instr;
 }
 
+void HOptimizedGraphBuilder::PropertyAccessInfo::MarkAsInitializingStore() {
+  DCHECK_EQ(STORE, access_type_);
+  store_mode_ = INITIALIZING_STORE;
+}
+
+StoreFieldOrKeyedMode HOptimizedGraphBuilder::PropertyAccessInfo::StoreMode() {
+  DCHECK_EQ(STORE, access_type_);
+  if (IsTransition()) return INITIALIZING_STORE;

[Toon Verwaest, 2017/01/16 11:53:31]

if IsTransition() is true, store_mode_ should just be INITIALIZING_STORE as
well...

[Igor Sheludko, 2017/01/16 12:02:59]

Done.

+  return store_mode_;
+}
+
 Handle<FieldType>
 HOptimizedGraphBuilder::PropertyAccessInfo::GetFieldTypeFromMap(
     Handle<Map> map) const {