x86: Don't set Prefer_No_AVX512 for processors with AVX512 and AVX-VNNI

Don't set Prefer_No_AVX512 on processors with AVX512 and AVX-VNNI since
they won't lower CPU frequency when ZMM load and store instructions are
used.

diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c
index be2498b2e7cb6216f0926c3db1912d247e617ff9..311ade1f2632c02d2ccb4451887624c10a96cb96 100644 (file)
--- a/sysdeps/x86/cpu-features.c
+++ b/sysdeps/x86/cpu-features.c
@@ -538,8 +538,11 @@ init_cpu_features (struct cpu_features *cpu_features)
          |= bit_arch_Prefer_No_VZEROUPPER;
       else
        {
-         cpu_features->preferred[index_arch_Prefer_No_AVX512]
-           |= bit_arch_Prefer_No_AVX512;
+         /* Processors with AVX512 and AVX-VNNI won't lower CPU frequency
+            when ZMM load and store instructions are used.  */
+         if (!CPU_FEATURES_CPU_P (cpu_features, AVX_VNNI))
+           cpu_features->preferred[index_arch_Prefer_No_AVX512]
+             |= bit_arch_Prefer_No_AVX512;
 
          /* Avoid RTM abort triggered by VZEROUPPER inside a
             transactionally executing RTM region.  */