During the ISO C++ Committee meeting plenary session the C++23 Standard
has been voted as technical complete.
This updates the reference to c++2b to c++23 and updates the __cplusplus
macro.
Drive-by fixes c++1z -> c++17 and c++2a -> c++20 when seen.
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D149553
The itanium ABI represents the PMF as a pair of pointers. As such the
structure cannot be passed through a single register. Diagnose such
cases in the frontend rather than trying to generate IR to perform this
operation.
Fixes: 59033
Differential Revision: https://reviews.llvm.org/D13851
Reviewed By: aaron.ballman