Positive options: -mapx-features=<comma-separated-features>
Negative options: -mno-apx-features=<comma-separated-features>
-m[no-]apx-features is designed to be able to control separate APX
features.
Besides, we also support the flag -m[no-]apxf, which can be used like an
alias of -m[no-]apx-features=< all APX features covered by CPUID APX_F>
Behaviour when positive and negative options are used together:
For boolean flags, the last one wins
-mapxf -mno-apxf -> -mno-apxf
-mno-apxf -mapxf -> -mapxf
For flags that take a set as arguments, it sets the mask by order of the
flags
-mapx-features=egpr,ndd -mno-apx-features=egpr -> -egpr,+ndd
-mapx-features=egpr -mno-apx-features=egpr,ndd -> -egpr,-ndd
-mno-apx-features=egpr -mapx-features=egpr,ndd -> +egpr,+ndd
-mno-apx-features=egpr,ndd -mapx-features=egpr -> -ndd,+egpr
The design is aligned with gcc
https://gcc.gnu.org/pipermail/gcc-patches/2023-August/628905.html
6d6baef5c9