This seems an odd strategy for an accelerator. How are they expecting that people will use these new instructions? Only through Apple-supplied closed source compilers and libraries? (This is not meant to indicate you're wrong, only I'm confused about Apple's strategy)
That is similar to Intel providing such functions in a library for their CPUs (https://software.intel.com/content/www/us/en/develop/tools/o...).
A difference, of course, is that Apple can ship it with its OS, and does so.
I would guess they’re not or not yet willing to commit to shipping these instructions in future hardware (possibly, but that is more guesswork, because they have to work around bugs to use them. Those NOPs this article is talking about might be to work around them)
This sounds right. Forcing people to use Apple supplied and supported libraries allows Apple to make major changes in hardware without breaking compatibility (there are always edge cases, though).
There’s no publicly available compiler, proprietary or not, that produces binaries that use the instructions.
Today, that doesn’t save binaries not distributed through the store or ones you compiled yourself via other compiler chains.
It is possible to change that. One could even imagine it as part of the loading procedure.
Apple does not provide any support for using directly their undocumented ISA extensions, or their undocumented GPU, NPU etc.