[clang] [clang-cl] Add support for [[msvc::constexpr]] C++11 attribute (PR #71300)

[Vlad Serebrennikov via cfe-commits]

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@@ -0,0 +1,16 @@
+// RUN: %clang_cc1 -fms-compatibility -fms-compatibility-version=19.33 -std=c++20 -verify=supported %s
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Endilll wrote:

Judging by the failure https://lab.llvm.org/buildbot/#/builders/60/builds/15037, you might want to test for specific triples.

https://github.com/llvm/llvm-project/pull/71300