chore(mge/imperative): fix BackwardGraph for jit.trace

GitOrigin-RevId: 16e86a21d75ab467541b625289478c88ff175e1c

imperative/python/megengine/jit/tracing.py

@@ -254,6 +254,7 @@ class trace:
 
     def _compile(self):
         graph = self._graph = G.Graph()
+        graph.options.no_force_inplace = True
         # graph.options.graph_opt_level = 0
         need_reset_nodes = self._need_reset_nodes = []
         # links enforce ordering of I/O nodes

imperative/python/src/graph_rt.cpp

@@ -105,6 +105,7 @@ void init_graph_rt(py::module m) {
         DEF_READWRITE(enable_grad_var_static_reshape)
         DEF_READWRITE(enable_memory_swap)
         DEF_READWRITE(comp_node_seq_record_level)
+        DEF_READWRITE(no_force_inplace)
         // DEF_READWRITE(eager_evaluation)
         // DEF_READWRITE(imperative_proxy_graph)
         // DEF_READWRITE(extra_vardeps)

imperative/src/include/megbrain/imperative/ops/backward_graph.h

@@ -81,6 +81,18 @@ public:
         return m_graph;
     }
 
+    bool is_same_st(const Hashable& rhs) const override {
+        if (!rhs.same_type<BackwardGraph>()) {
+            return false;
+        }
+        auto& other = rhs.cast_final_safe<BackwardGraph>();
+        if (this == &other) {
+            return true;
+        }
+        // FIXME
+        return false;
+    }
+
 private:
     InternalGraph m_graph;
 };