They do when using hardned runtimes configuration, which was compiler specific, and starting with C++26 is officially part of the standard.
It naturally doesn't cover C style programming in C++.
It naturally doesn't cover C style programming in C++.
In practice, it depends on how the contracts drama folds out.
However I do agree it is still not quite there.
Still, C++ isn't going anywhere anytime soon, so any improvement is welcomed, even rustc has to gain from it.
I don't expect any RIR for GCC and LLVM happening any time soon, not only due to existing code, also due to all universities, and companies that contribute to upstream and aren't racing to adopt Rust.