Comment by baddash | Hacker News Reader

Comment by baddash | Hacker News Reader

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Just a note: in the e-mail thread, it's only stated as a possibility that this patchset will be implemented in time for GCC 9. The only real news is that this patchset has been greenlit.

By the way; I'm confused trying to make sense of the effects of this patchset. In Andrew Stubbs' original e-mail, he states that the patchset which is discussed in this e-mail thread is for the "non-OpenACC/OpenMP portions" of the port. Not only that, but only C and Fortran are supported, C++ is explicitly unsupported, and everything else is untested.

So then, that means definite effects of implementing this patchset will be that the front-end which is non-OpenACC/OpenMP for C and Fortran will be operational, plus whatever the effects are of the patches with unspecified details for different areas (backend, config, and testsuite) which he mentioned briefly.

Given these definite effects, what are the noteworthy or most important effects of them? How much does this "power on" GCN?

> C++ is explicitly unsupported

Given that C++ now has a defined memory model, it might very well be that it's now impossible to implement C++ in a standard conforming way on exotic architectures.

> Given that C++ now has a defined memory model, it might very well be that it's now impossible to implement C++ in a standard conforming way on exotic architectures.

Also C has a defined memory model since C11

> https://davmac.wordpress.com/2018/01/28/understanding-the-c-...

and it is the same as the memory model from C++11:

> https://en.wikipedia.org/w/index.php?title=Memory_model_(pro...

"After it was established that threads could not be implemented safely as a library without placing certain restrictions on the implementation and, in particular, that the C and C++ standards (C99 and C++03) lacked necessary restrictions, the C++ threading subcommittee set to work on suitable memory model; in 2005, they submitted C working document n1131 to get the C Committee on board with their efforts. The final revision of the proposed memory model, C++ n2429, was accepted into the C++ draft standard at the October 2007 meeting in Kona. The memory model was then included in the next C++ and C standards, C++11 and C11.".

C11 has pretty much the same memory model.

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