cmake: leave the timestamp out of precompiled headers on clang - #28816
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ServeurpersoCom merged 1 commit intoSep 12, 2026
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Clang stores the modification time of the precompiled header sources inside the header and refuses the header when they differ. A cached header restored from another checkout carries the timestamps of that checkout, so the build fails. The option covers the compilers ccache treats as MSVC while they are clang underneath, clang-cl and the Intel LLVM drivers.
CISC
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Sep 12, 2026
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Since the SYCL cache is only written on pushes to master, I'll run the two-push sequence on my fork first to confirm a restored header is accepted. |
taronaeo
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Sep 12, 2026
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Done, and it holds: the second run restores the entry written by the first, reaches 218/221 hits and recompiles ggml-cpu.cpp against the restored header with no complaint. run 1: https://github.com/ServeurpersoCom/llama.cpp/actions/runs/34715527552/job/103611954850 |
pl752
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Sep 15, 2026
…org#28816) Clang stores the modification time of the precompiled header sources inside the header and refuses the header when they differ. A cached header restored from another checkout carries the timestamps of that checkout, so the build fails. The option covers the compilers ccache treats as MSVC while they are clang underneath, clang-cl and the Intel LLVM drivers.
quimmedes
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Sep 16, 2026
…org#28816) Clang stores the modification time of the precompiled header sources inside the header and refuses the header when they differ. A cached header restored from another checkout carries the timestamps of that checkout, so the build fails. The option covers the compilers ccache treats as MSVC while they are clang underneath, clang-cl and the Intel LLVM drivers.
zsogitbe
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Sep 17, 2026
…org#28816) Clang stores the modification time of the precompiled header sources inside the header and refuses the header when they differ. A cached header restored from another checkout carries the timestamps of that checkout, so the build fails. The option covers the compilers ccache treats as MSVC while they are clang underneath, clang-cl and the Intel LLVM drivers.
Te-eMster
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Sep 18, 2026
…org#28816) Clang stores the modification time of the precompiled header sources inside the header and refuses the header when they differ. A cached header restored from another checkout carries the timestamps of that checkout, so the build fails. The option covers the compilers ccache treats as MSVC while they are clang underneath, clang-cl and the Intel LLVM drivers.
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Overview
icx is clang underneath, so it stores the mtime of the precompiled header sources inside the .pch and rejects the header once those timestamps move, which is what happens whenever ccache restores a header built from an earlier checkout: https://github.com/ggml-org/llama.cpp/actions/runs/34686896609/job/103535335025. This leaves the timestamp out of the header for clang and Intel LLVM compilers, MSVC and GCC are untouched.
cc @CISC
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