Intel Eliminates Support for Knights Mill and Knights Landing Xeon Phi in LLVM 19

Intel Eliminates Support for Knights Mill and Knights Landing Xeon Phi in LLVM 19

Intel has made the decision to remove support for Xeon Phi in the upcoming LLVM/Clang 19 compiler release, following the deprecation of support in LLVM/Clang 18 earlier this year. This move mirrors GCC’s decision to deprecate and then remove Xeon Phi support in their recent releases as well. The removal of support for Xeon Phi aligns with Intel’s announcement of the end-of-life of these products in August 2017.

The decision to remove support for Xeon Phi in LLVM/Clang 19 was based on several factors. Intel highlighted that the support for these products in LLVM/Clang was incomplete, with missing intrinsic and assembly support for AVX5124FMAPS instructions, causing poor performance in some cases due to incorrect use of options. The company also mentioned that previous versions of ICC and ICX had removed support for Xeon Phi and reported bugs, and they wanted to reduce maintenance efforts by aligning with GCC’s decision to remove support as well.

In a recent commit on GitHub, ISA support for Knights Mill and Knights Landing was removed overnight in response to Intel’s decision to discontinue support for Xeon Phi in LLVM/Clang 19. This move indicates Intel’s commitment to streamlining support for their products across different compilers and reducing the maintenance burden associated with supporting deprecated hardware.

This decision by Intel to remove support for Xeon Phi in LLVM/Clang 19 underscores the importance of staying updated with the latest compiler releases and aligning with industry standards. Users who still rely on Xeon Phi for their projects may need to consider using older versions of LLVM/Clang or switch to alternative hardware that is still supported by the latest compiler releases.

Overall, the removal of Xeon Phi support in LLVM/Clang 19 marks a significant milestone in the evolution of compiler support for legacy hardware and highlights the challenges faced by developers in maintaining compatibility with outdated products. Intel’s decision reflects the company’s focus on optimizing performance and reducing maintenance efforts for their products. Developers and users of Xeon Phi will need to adapt to this change and consider alternative solutions for their projects moving forward.

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https://www.phoronix.com/news/LLVM-19-Drops-Xeon-Phi