Metamorphic Testing of Deep Learning Compilers

The prosperous trend of deploying deep neural network (DNN) models to diverse hardware platforms has boosted the development of deep learning (DL) compilers. DL compilers take high-level DNN model specifications as input and generate optimized DNN executables for diverse hardware architectures like CPUs, GPUs, and hardware accelerators. We introduce MT-DLComp, a metamorphic testing framework specifically designed for DL compilers to uncover erroneous compilations. Our approach leverages deliberately-designed metamorphic relations (MRs) to launch semantics-preserving mutations toward DNN models to generate their variants. This way, DL compilers can be automatically tested for compilation correctness by comparing the execution outputs of the compiled DNN models and their variants without manual intervention. We detected over 435 inputs that can result in erroneous compilations in four popular DL compilers, all of which are industry-strength products maintained by Amazon, Facebook, Microsoft, and Google. We uncovered four bugs in these compilers by debugging them using the error-triggering inputs.