Compiler builtin for std::launder

Hi,

https://libcxx.llvm.org/cxx1z_status.html lists Core Issue 1776: Replacement of class objects containing reference members (et al) (std::launder) as Complete in Clang/libc++ 6.0, but I didn't see a corresponding compiler builtin documented at https://clang.llvm.org/docs/LanguageExtensions.html .

I'm assuming that such a builtin was implemented - can it be documented (or can someone tell me what it's spelled) so I can request C1XX and EDG support for the same builtin?

Thanks,
STL

It's spelt __builtin_launder. See https://reviews.llvm.org/D40218