Re: warning: unknown and unstable feature specified for `-Ctarget-feature`: `mma`

[Mukesh Kumar Chaurasiya]

On Thu, Sep 17, 2026 at 03:38:46PM +0200, kernel test robot wrote:
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head:   238650ef6c7c7cca08e032527329424c9fbd70e5
> commit: bc87cbdb952e9223616b839d64bdb4723aa2ed1d powerpc: Enable Rust for ppc64le
> date:   7 weeks ago
> config: powerpc64-randconfig-r2201-20260917 (https://download.01.org/0day-ci/archive/20260917/202609171549.xeqQabC6-lkp@xxxxxxxxx/config)
> compiler: clang version 17.0.6 (https://github.com/llvm/llvm-project 6009708b4367171ccdbf4b5905cb6a803753fe18)
> rustc: rustc 1.96.0 (ac68faa20 2026-05-25)
> smatch: v0.5.0-9187-g5189e3fb
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260917/202609171549.xeqQabC6-lkp@xxxxxxxxx/reproduce)
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Fixes: bc87cbdb952e ("powerpc: Enable Rust for ppc64le")
> | Reported-by: kernel test robot <lkp@xxxxxxxxx>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202609171549.xeqQabC6-lkp@xxxxxxxxx/
> 
> All warnings (new ones prefixed by >>):
> 
> >> warning: unknown and unstable feature specified for `-Ctarget-feature`: `mma`
>    |
>    = note: it is still passed through to the codegen backend, but use of this feature might be unsound and the behavior of this feature can change in the future
>    = help: consider filing a feature request
> --
> >> warning: unstable feature specified for `-Ctarget-feature`: `vsx`
>    |
>    = note: this feature is not stably supported; its behavior can change in the future
> --
> >> warning: unknown and unstable feature specified for `-Ctarget-feature`: `hard-float`
>    |
>    = note: it is still passed through to the codegen backend, but use of this feature might be unsound and the behavior of this feature can change in the future
>    = help: consider filing a feature request
> --
> >> warning: unstable feature specified for `-Ctarget-feature`: `altivec`
>    |
>    = note: this feature is not stably supported; its behavior can change in the future
> 
> --
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests/wiki

This is expected, the issue for the same is raised to rust-lang.

Regards,
Mukesh