[PATCH] D73550: Prevent building with MSVC 14.24

Tue Jan 28 06:59:22 PST 2020

hans added a comment.

Seems reasonable to me. Should we comment on the upstream bug that this breaks LLVM? I see there's a reduced repro, but I don't see LLVM mentioned.

On second thought, while it's not strictly our problem, what is a user who runs into this supposed to do? AFAIK, Microsoft doesn't provide access to old compiler versions within the same family (2019), so unless you have an old install lying around or want to try the next preview, what to do? Would it be better to selectively disable optimization of the miscompiled function?

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Comment at: llvm/include/llvm/Support/Compiler.h:31
+// and thread "[llvm-dev] Longstanding failing tests - clang-tidy, MachO, Polly"
+// on llvm-dev Jan 21-23 2020.
+#error "MSVC 19.24 version of MSVC is known to miscompile LLVM."
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Maybe link to http://lists.llvm.org/pipermail/llvm-dev/2020-January/138496.html ?

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https://reviews.llvm.org/D73550