* test case

tests/python/relay/test_backend_compile_engine.py

@@ -33,6 +33,17 @@ def get_func(shape):
                 y.asnumpy(), x.asnumpy() * 3)
     engine.dump()
 
+def test_compile_placeholder_bypass():
+    engine = relay.backend.compile_engine.get()
+    x = relay.var("x", shape=(2, 3))
+    y = relay.var("y", shape=(2, 3))
+    z = relay.var("z", shape=(2, 3))
+    result = relay.Tuple([relay.op.concatenate([y, z], axis=0)])
+    #result = relay.Tuple([x, relay.op.concatenate([y, z], axis=0)])
+    func = relay.Function(relay.ir_pass.free_vars(result), result)
+    with relay.build_config(opt_level=3):
+       graph, lib, params = relay.build(func, 'llvm')
 
 if __name__ == "__main__":
     test_compile_engine()
+    test_compile_placeholder_bypass()