From Effectiveness to Efficiency: Comparative Evaluation of Code Generated by LCGMs for Bilingual Programming Questions

Large Code Generation Models (LCGMs) have garnered significant attention and achieved promising results across various programming tasks. However, concerns arise regarding performance when using non-English prompts, as these models are primarily trained on English-centric corpora, and most programming language tokens resemble English. Existing benchmarks often rely on English programming questions and limited manual unit test cases, inadequately assessing LCGM-generated code quality. This paper investigates code quality differences, specifically effectiveness and efficiency, when employing different natural languages as inputs, focusing on Chinese and English due to their prominent corpora and LCGM availability. Evaluating LCGM-generated code quality under bilingual inputs presents three challenges: (1) lack of high-quality bilingual programming question datasets, (2) insufficient unit test cases for comprehensive correctness verification, and (3) limited support for comparing generated code performance. To address these challenges, we curated a test suite of 52 bilingual programming questions and developed automated input generators for each. We enhanced correctness verification by sampling larger unit test cases and estimated code performance by profiling execution time relative to input size growth. Using this framework, we conducted an empirical study on six state-of-the-art LCGMs. The results revealed that LCGM-generated code exhibits varying bilingual correctness on an average of 10.5% of tasks, with 39.5% of correct code showing diverse bilingual performance differences. Our findings suggested LCGMs may not consistently generate high-quality code across different languages, providing insights for future research directions.