llvm / llvm/llvm-project

[Windows] LLVM build failure with VS Clang 20.1

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build-problem platform:windows
Dominant language
LLVM
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Description

Trying to
- build LLVM (tried master and the 21.1.7 tag)
- under Windows
- using the LLVM 20 toolset shipped with Visual Studio 2026
- using MSVC or ClangCL works but trying with Clang 'proper' (the standard GNU interface) the build fails with this linker error:
lld-link: error: undefined symbol: void * __cdecl operator new[](unsigned __int64, class clang::ASTContext const &, unsigned __int64))
(using LTO in all cases)

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