insert copy op

Author: zhiics

src/relay/pass/fuse_ops.cc

@@ -823,6 +823,16 @@ class FuseMutator : private ExprMutator {
         if (new_fields[i].as<VarNode>()) {
           auto copy = Copy(new_fields[i]);
           new_fields.Set(i, copy);
+        } else if (new_fields[i].as<CallNode>()) {
+          size_t j = 0;
+          while (j < i) {
+            if (new_fields[j] == new_fields[i]) break;
+            j++;
+          }
+          if (j != i) {
+            auto copy = Copy(new_fields[i]);
+            new_fields.Set(i, copy);
+          }
         }
       }
       return MakeNewFunction(ret_group, tuple->checked_type(), TupleNode::make(new_fields));