[llvm] [TargetParser][AArch64] Believe runtime feature detection (PR #95694)

[via llvm-commits]

workingjubilee wrote:

> Oh I was meaning in llvm/unittests/TargetParser/Host.cpp. It has tests for parsing things that look like cpuinfo.

Sure, but it doesn't have any tests for `sys::getHostCPUFeatures`, because there are none, because the entire schematic for looking up host features is "do something target-dependent at runtime", and thus is currently untestable, unless someone alters the signature for that function for every single platform...

...and considering my incredibly meager C++ knowledge, it seems _less_ effort to simply fix the definitions of the Armv8-A Cortex targets.

https://github.com/llvm/llvm-project/pull/95694