[libcxx] [llvm] [libc++] Updates the compilers used post LLVM-20 branching. (PR #126564)

[Nikolas Klauser via llvm-commits]

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@@ -12,7 +12,7 @@
 // UNSUPPORTED: c++03
 
 // TODO: Investigate these failures which break the CI.
-// UNSUPPORTED: clang-18, clang-19, clang-20
+// UNSUPPORTED: clang-18, clang-19, clang-20, clang-21
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philnik777 wrote:

It's not been broken. Our CI is. This actually works for every clang version listed here, except in the CI.

https://github.com/llvm/llvm-project/pull/126564