llvm-project

d1bcac06 - [Clang] Bump `__cpp_constexpr` to `202002L` in C++20 mode (#129814)

[Clang] Bump `__cpp_constexpr` to `202002L` in C++20 mode (#129814) Per P2493R0 and SD6, `__cpp_constexpr` of value `202002L` indicates that P1330R0 "Changing the active member of a union inside constexpr" is implemented, which is true for Clang 9 and later.