[clang] Accept -std=c++23/gnu++23 rather than c++2b, like gcc does

[Romain-Geissler-1A]

Hi,

gcc already accepts the C++ dialects c++23/gnu++23, and checking right now on Compiler Explorer it seems clang does not. C++23 isn't finalized yet, however it is shaping up and has already reached the feature freeze phase. Most likely it will be officially formalized in 2023. Is it time to start accepting -std=c++23/-std=gnu++23 in clang ?

Cheers,
Romain

[llvmbot]

@llvm/issue-subscribers-clang-frontend

[llvmbot]

@llvm/issue-subscribers-clang-driver

[AaronBallman]

We typically wait for the standard to be ratified before doing that, but at the end of the day, if the standard is ratified in 2024, we'd just accept c++23 as an alias for c++24 same as we do with c90/c89. Interestingly, GCC does not accept -std=c23 yet.

[llvmbot]

@llvm/issue-subscribers-c-2b

[Romain-Geissler-1A]

Hi,

I am not sure this if this is ok to implement this now. Last time for C++20 it seems it was done in February 2020: 24ad121

[AaronBallman]

I think we're good to go for renaming C++2b to C++23 now (any ballot comments received by WG21 at this stage will be handled as issues against C++2c instead). CC @hubert-reinterpretcast as C++ conformance code owner

[Romain-Geissler-1A]

This is implemented on the main branch now, so closing this.