Good questions. For computer support, generally you would pass a -mcpu= flag (or maybe -mattr=, but that might be a compiler internal flag, I forget). Obviousl

Good questions. For computer support, generally you would pass a -mcpu= flag (or maybe -mattr=, but that might be a compiler internal flag, I forget). Obviously then that's not portable and has implications on the ABI. I didn't read the article but I suspect they might be in ARMv9.0, hopefully, otherwise "better luck next major revision." For monkey patching, the Linux kernel already does this aggressively since it generally has permission to read the relevant machine specific registers (MSRs). Doesn't help userspace, but userspace can do something similar with hwcaps and ifuncs.