diff --git a/llvm/include/llvm/Support/Compiler.h b/llvm/include/llvm/Support/Compiler.h index 34d8ed8baf2d..a583b2d547ad 100644 --- a/llvm/include/llvm/Support/Compiler.h +++ b/llvm/include/llvm/Support/Compiler.h @@ -24,6 +24,13 @@ #if defined(_MSC_VER) #include + +#if _MSC_VER == 1924 +// See https://developercommunity.visualstudio.com/content/problem/845933/miscompile-boolean-condition-deduced-to-be-always.html +// 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." +#endif #endif #ifndef __has_feature