GCC 15 Branch Test Suite Status: Commit 043c5c4be4f1

This article provides a detailed overview of the test suite status for the GCC 15 branch, specifically focusing on commit 043c5c4be4f1e15c87d0e0368075bac4470ad23e. This information is crucial for developers and users who want to understand the stability and reliability of the compiler at this particular stage of development. The report includes summaries of new, resolved, and unresolved failures across different target architectures and configurations. Let's dive into the specifics of this test suite status and what it means for the GCC project.

Understanding the Test Suite Results

The GCC (GNU Compiler Collection) is a critical tool for software development, and its stability is paramount. The test suite is a comprehensive set of tests designed to ensure that the compiler functions correctly across various scenarios. When a new commit is made, the test suite is run to identify any regressions or newly introduced issues. The results are categorized into three main areas: New Failures, Resolved Failures, and Unresolved Failures.

• New Failures: These are tests that previously passed but are now failing in the current commit. New failures can indicate a regression, meaning a change in the code has introduced a new bug. Identifying these failures quickly is crucial for maintaining the quality of the compiler.
• Resolved Failures: These are tests that were failing in previous commits but are now passing. This indicates that a bug fix or improvement has been successfully implemented, which is a positive sign for the project's health.
• Unresolved Failures: These are tests that continue to fail across multiple commits. Unresolved failures often represent more complex issues that require further investigation and potentially significant code changes. Tracking these failures is essential to ensure they are addressed in a timely manner.

Interpreting the Failure Counts

The test results are presented in a tabular format, showing the number of failures for gcc, g++, and gfortran. These represent the C, C++, and Fortran compilers, respectively. The failure counts are given as [number of failures]/[number of expected failures]. For instance, 241/94 in the gcc column means that 241 tests failed out of the 94 tests that were expected to fail (or are known to fail under certain conditions). A higher number of failures compared to the expected failures suggests potential problems that need attention.

The table also includes the Previous Hash, which is a link to the comparison between the current commit and the previous one. This is invaluable for developers as it allows them to quickly see the changes that were made and potentially identify the source of new failures. Analyzing the diff between commits can provide clues as to why a test is now failing.

Detailed Breakdown of Unresolved Failures

Let's examine the unresolved failures in more detail. These are the persistent issues that require ongoing attention. The table below summarizes the unresolved failures for various configurations:

Key Observations

• RISC-V Architectures: A significant number of unresolved failures are observed in configurations targeting the RISC-V architecture, particularly those involving rv32 and rv64 variants with different extensions (e.g., Bitmanip, Vector Crypto, gc, gcv). This suggests that the compiler may have ongoing issues with these specific instruction set architectures or their interactions with the toolchain.
• Newlib Configurations: Many failures are reported in configurations using the Newlib C library. Newlib is often used in embedded systems, indicating potential problems in this domain. The high number of failures in Newlib configurations warrants a closer look to ensure compatibility and correctness.
• Multilib Issues: Configurations marked with "multilib" also show a substantial number of failures. Multilib refers to the ability of a compiler to generate code for multiple target architectures or ABIs from a single build. Failures in multilib configurations can be particularly problematic as they affect a broader range of use cases.

Analyzing Specific Configurations

1. linux: RVA23U64 profile lp64d medlow multilib: This configuration shows a high number of failures in gcc (241/94) and a significant number in g++ (11/4). The lp64d signifies a 64-bit long pointer and double floating-point ABI, while medlow indicates a medium-low code model. The multilib aspect means that the compiler is built to support multiple ABIs. This configuration's failures could stem from issues in code generation for the specific ABI or interactions between the multilib setup and the target architecture.

2. newlib: rv32gcv ilp32d medlow multilib: This configuration has a very high number of gcc failures (442/131). The ilp32d signifies a 32-bit integer, long, and pointer ABI with double floating-point support. The rv32gcv indicates the RISC-V 32-bit architecture with the G (general-purpose), C (compressed instructions), and V (vector instructions) extensions. The combination of Newlib, RISC-V vector instructions, and multilib likely exposes a set of complex interactions that lead to these failures.

3. newlib: rv32imac_zba_zbb_zbc_zbs ilp32 medlow multilib: This configuration, along with several others including rv32imc_zba_zbb_zbc_zbs, rv32imc_zba_zbb_zbc_zbs_zicsr_zifencei, and their rv64 counterparts, consistently shows a high number of gcc failures (around 360/90). These configurations involve the RISC-V architecture with various extensions related to bit manipulation (zba, zbb, zbc, zbs), control and status register access (zicsr), and instruction-fetch fence (zifencei). The consistent failures across these configurations suggest a potential issue in how the compiler handles these newer RISC-V extensions, especially in the Newlib environment.

Implications and Next Steps

The test suite status for commit 043c5c4be4f1e15c87d0e0368075bac4470ad23e reveals several areas of concern within the GCC 15 branch. The high number of unresolved failures, particularly in RISC-V and Newlib configurations, indicates that further investigation and bug fixing are necessary. It is crucial for developers to:

1. Prioritize RISC-V and Newlib Issues: Given the prevalence of failures in these areas, they should be given immediate attention. This includes analyzing the specific tests that are failing and identifying the root causes.
2. Examine Multilib Interactions: The failures in multilib configurations suggest potential problems in how the compiler handles multiple target ABIs. This requires a thorough review of the multilib build process and code generation logic.
3. Investigate New RISC-V Extensions: The consistent failures related to the bit manipulation and other recent RISC-V extensions indicate a need for more in-depth testing and potential code adjustments to correctly support these features.
4. Leverage Previous Hash Comparisons: The links to previous commit comparisons are invaluable for identifying the changes that introduced new failures. Developers should use these links to pinpoint the source of regressions.

Conclusion

The test suite status for GCC 15 commit 043c5c4be4f1e15c87d0e0368075bac4470ad23e paints a picture of a compiler in active development with ongoing challenges. While there are unresolved failures, particularly in specific configurations, this level of detail allows developers to focus their efforts effectively. By addressing the identified issues, the GCC project can continue to improve the stability and reliability of this critical tool.

For more information on GCC testing and development, you can visit the official GNU Compiler Collection website.

Associated run details are available at: https://github.com/patrick-rivos/gcc-postcommit-ci/actions/runs/19792370841