[PATCH v2 1/1] sysdeps/x86: set Prefer_No_AVX512 for Hygon model 0x7

[Jiamei Xie]

Benchmarks on Hygon hardware show that EVEX often outperforms AVX-512.
To reflect this, enable the Prefer_No_AVX512 flag for model 0x7 so that
the ifunc selector will favor EVEX paths over AVX-512 for that model.

Signed-off-by: Li jing <lijing@hygon.cn>
Signed-off-by: Xie jiamei <xiejiamei@hygon.cn>
---
 sysdeps/x86/cpu-features.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c
index b67ef541dd..4ec4c43718 100644
--- a/sysdeps/x86/cpu-features.c
+++ b/sysdeps/x86/cpu-features.c
@@ -1123,6 +1123,11 @@ disable_tsx:
        hardware.  */
       cpu_features->preferred[index_arch_Avoid_Non_Temporal_Memset]
 	    &= ~bit_arch_Avoid_Non_Temporal_Memset;
+
+      /* On Hygon model 0x7, benchmarks show EVEX often beats AVX-512 */
+      if (model == 0x7)
+        cpu_features->preferred[index_arch_Prefer_No_AVX512]
+          |= bit_arch_Prefer_No_AVX512;
     }
   else
     {
-- 
2.17.1