[libcxx-commits] [libcxx] [libc++] P2747R2: `constexpr` placement new (library part) (PR #105768)

[Mital Ashok via libcxx-commits]

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@@ -510,7 +510,9 @@ __cpp_lib_void_t                                        201411L <type_traits>
 # undef  __cpp_lib_bind_front
 # define __cpp_lib_bind_front                           202306L
 # define __cpp_lib_bitset                               202306L
-// # define __cpp_lib_constexpr_new                        202406L
+# if !defined(_LIBCPP_ABI_VCRUNTIME)
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MitalAshok wrote:

Do we want a check for `__cpp_constexpr >= 202406L` here too? `constexpr operator new` has been valid since C++23 but isn't usable without compiler support, and users might check `defined(__cpp_lib_constexpr_new)` instead of `defined(__cpp_lib_constexpr_new) && __cpp_constexpr >= 202406L`

https://github.com/llvm/llvm-project/pull/105768