Deep Learning (DL) compilers typically load a DL model and optimize it with intermediate representation. Existing DL compiler testing techniques mainly focus on model optimization stages, but rarely explore bug detection at the model loading stage. Effectively testing the model loading stage requires covering diverse usages of each DL operator from various DL libraries, which shares a common objective with DL library testing, indicating that the embedded knowledge in DL library tests is beneficial for testing the model loading stage of DL compilers. With this idea, we propose Opera to migrate the knowledge embedded in DL library tests to test the model loading stage. Opera constructs diverse tests from various tests for DL libraries (including the tests documented in DL libraries and those generated by recent fuzzers). In total, we considered three sources of tests in DL libraries for migration. In addition, it incorporates a diversity-based test prioritization strategy to migrate and execute those tests that are more likely to detect diverse bugs earlier. We then used eight frontends from three DL compilers (e.g., TVM, TensorRT, and OpenVINO) for evaluation. OPERA detected 170 previously unknown bugs in total, 90 of which have been confirmed/fixed by developers, demonstrating the effectiveness of such the migration-based idea. The test prioritization strategy in OPERA improves testing efficiency with migrated tests by$11.9 \% \sim 47.4 \%$on average compared to general test prioritization strategies.

Java Virtual Machine (JVM) holds a crucial position in executing various Java programs, thereby necessitating rigorous testing to ensure software reliability and security. Regarding existing JVM testing techniques, synthesis-based techniques have proven to be state-of-the-art, which construct a test program by synthesizing various program ingredients extracted from historical bug-revealing test programs into a seed program. However, existing synthesis-based techniques directly use the program ingredients specific to historical bugs, which limits the test scope without the ability of covering more JVM features and negatively affects the diversity of synthesized test programs.

Due to the critical role of compilers, many compiler testing techniques have been proposed, two most notable categories among which are grammar-based and metamorphic-based techniques. All of them have been extensively studied for testing mature compilers. However, it is typical to develop a new compiler for a new-born programming language in practice. In this scenario, the existing techniques are hardly applicable due to some major reasons: (1) no reference compilers to support differential testing, (2) lack of program analysis tools to support most of metamorphic-based compiler testing, (3) substantial implementation effort incurred by different programming language features. Hence, it is unknown how the existing techniques perform in this new scenario.