1 files changed, 12 insertions, 0 deletions
diff --git a/libatomic/config/x86/init.c b/libatomic/config/x86/init.c
index 7bdec72..6f6499c 100644
--- a/libatomic/config/x86/init.c
+++ b/libatomic/config/x86/init.c
@@ -34,6 +34,18 @@ __libat_feat1_init (void)
   unsigned int eax, ebx, ecx, edx;
   FEAT1_REGISTER = 0;
   __get_cpuid (1, &eax, &ebx, &ecx, &edx);
+#ifdef __x86_64__
+  if ((FEAT1_REGISTER & (bit_AVX | bit_CMPXCHG16B))
+      == (bit_AVX | bit_CMPXCHG16B))
+    {
+      /* Intel SDM guarantees that 16-byte VMOVDQA on 16-byte aligned address
+	 is atomic, but so far we don't have this guarantee from AMD.  */
+      unsigned int ecx2 = 0;
+      __get_cpuid (0, &eax, &ebx, &ecx2, &edx);
+      if (ecx2 != signature_INTEL_ecx)
+	FEAT1_REGISTER &= ~bit_AVX;
+    }
+#endif
   /* See the load in load_feat1.  */
   __atomic_store_n (&__libat_feat1, FEAT1_REGISTER, __ATOMIC_RELAXED);
   return FEAT1_REGISTER;