Constant fold strict comparison based on incoming types: different (exact) types means that the res…

runtime/vm/flow_graph_type_propagator.cc

Index: runtime/vm/flow_graph_type_propagator.cc
===================================================================
--- runtime/vm/flow_graph_type_propagator.cc	(revision 30082)
+++ runtime/vm/flow_graph_type_propagator.cc	(working copy)
@@ -894,6 +894,18 @@
     return CompileType::FromAbstractType(
         AbstractType::ZoneHandle(StaticField().type()));
   }
+  const Field& field = this->StaticField();
+  ASSERT(field.is_static());
+  if (field.is_final()) {
+    Instance& obj = Instance::Handle(field.value());
+    if ((obj.raw() != Object::sentinel().raw()) &&
+        (obj.raw() != Object::transition_sentinel().raw()) &&
+        !obj.IsNull()) {
+      return CompileType(CompileType::kNonNullable,
+                         Class::Handle(obj.clazz()).id(),
+                         NULL);
+    }
+  }
   return CompileType::Dynamic();
 }