[PATCH v2] [libatomic]: Handle AVX+CX16 ZHAOXIN like intel for 16b atomic [PR104688]

[Jakub Jelinek]

On Thu, Jul 18, 2024 at 03:23:05PM +0800, MayShao-oc wrote:
> From: mayshao <mayshao-oc@zhaoxin.com>
> 
> Hi Jakub:
> 
>     Thanks for your review,We should just amend this to handle Zhaoxin.
> 
>     Bootstrapped /regtested X86_64.
> 
>     Ok for trunk?
> BR
> Mayshao
> 
> libatomic/ChangeLog:
> 
> 	PR target/104688
> 	* config/x86/init.c (__libat_feat1_init): Don't clear
> 	bit_AVX on ZHAOXIN CPUs.
> ---
>  libatomic/config/x86/init.c | 13 ++++++++-----
>  1 file changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/libatomic/config/x86/init.c b/libatomic/config/x86/init.c
> index a75be3f175c..0d6864909bb 100644
> --- a/libatomic/config/x86/init.c
> +++ b/libatomic/config/x86/init.c
> @@ -39,12 +39,15 @@ __libat_feat1_init (void)
>        == (bit_AVX | bit_CMPXCHG16B))
>      {
>        /* Intel SDM guarantees that 16-byte VMOVDQA on 16-byte aligned address
> -	 is atomic, and AMD is going to do something similar soon.
> -	 We don't have a guarantee from vendors of other CPUs with AVX,
> -	 like Zhaoxin and VIA.  */
> -      unsigned int ecx2 = 0;
> +	 is atomic, and AMD is going to do something similar soon. Zhaoxin also

Two spaces before Zhaoxin (and also should go on another line).

> +	 guarantees this. We don't have a guarantee from vendors of other CPUs 

Two spaces before We (and again, the line will be too long).

> +	 with AVX,like VIA.  */

Space before like

> +      unsigned int ecx2 = 0, family = 0;
> +      family = (eax >> 8) & 0x0f;
>        __get_cpuid (0, &eax, &ebx, &ecx2, &edx);
> -      if (ecx2 != signature_INTEL_ecx && ecx2 != signature_AMD_ecx)
> +      if (ecx2 != signature_INTEL_ecx && ecx2 != signature_AMD_ecx

If the whole condition can't fit on one line, then each subcondition should
be on a separate line, so linebreak + indentation should be added also
before && ecx2 != signature_AMD_ecx

> +          && !(ecx2 == signature_CENTAUR_ecx && family > 0x6)
> +          && ecx2 != signature_SHANGHAI_ecx)
>  	FEAT1_REGISTER &= ~bit_AVX;
>      }
>  #endif
> -- 
> 2.27.0

Otherwise LGTM, but please give Uros a day or two to chime in.

	Jakub