Merged: [turbofan] Fix deopt check for storing into constant field.

src/compiler/js-native-context-specialization.cc

Index: src/compiler/js-native-context-specialization.cc
diff --git a/src/compiler/js-native-context-specialization.cc b/src/compiler/js-native-context-specialization.cc
index 1881cd02bc538e8ea0a031274293e3db7b03c891..35b3c82756bee89dc6ebd8609e9827c2ec28e7bc 100644
--- a/src/compiler/js-native-context-specialization.cc
+++ b/src/compiler/js-native-context-specialization.cc
@@ -818,13 +818,14 @@ JSNativeContextSpecialization::BuildPropertyAccess(
     DCHECK_EQ(AccessMode::kLoad, access_mode);
     value = jsgraph()->UndefinedConstant();
   } else if (access_info.IsDataConstant()) {
-    value = jsgraph()->Constant(access_info.constant());
+    Node* constant_value = jsgraph()->Constant(access_info.constant());
     if (access_mode == AccessMode::kStore) {
-      Node* check =
-          graph()->NewNode(simplified()->ReferenceEqual(), value, value);
+      Node* check = graph()->NewNode(simplified()->ReferenceEqual(), value,
+                                     constant_value);
       effect =
           graph()->NewNode(simplified()->CheckIf(), check, effect, control);
     }
+    value = constant_value;
   } else if (access_info.IsAccessorConstant()) {
     // TODO(bmeurer): Properly rewire the IfException edge here if there's any.
     Node* target = jsgraph()->Constant(access_info.constant());