Index: config/aarch64/driver-aarch64.c
===================================================================
--- config/aarch64/driver-aarch64.c	(revision 241437)
+++ config/aarch64/driver-aarch64.c	(working copy)
@@ -169,7 +169,6 @@ host_detect_local_cpu (int argc, const c
   bool tune = false;
   bool cpu = false;
   unsigned int i = 0;
-  unsigned int core_idx = 0;
   unsigned char imp = INVALID_IMP;
   unsigned int cores[2] = { INVALID_CORE, INVALID_CORE };
   unsigned int n_cores = 0;
@@ -219,18 +218,13 @@ host_detect_local_cpu (int argc, const c
       if (strstr (buf, "part") != NULL)
 	{
 	  unsigned ccore = parse_field (buf);
-	  for (i = 0; aarch64_cpu_data[i].name != NULL; i++)
-	    if (ccore == aarch64_cpu_data[i].part_no
-		&& !contains_core_p (cores, ccore))
-	      {
-		if (n_cores == 2)
-		  goto not_found;
-
-		cores[n_cores++] = ccore;
-		core_idx = i;
-		arch_id = aarch64_cpu_data[i].arch;
-		break;
-	      }
+	  if (!contains_core_p (cores, ccore))
+	    {
+	      if (n_cores == 2)
+		goto not_found;
+
+	      cores[n_cores++] = ccore;
+	    }
 	  continue;
 	}
       if (!tune && !processed_exts && strstr (buf, "Features") != NULL)
@@ -276,11 +270,19 @@ host_detect_local_cpu (int argc, const c
   if (n_cores == 0 || n_cores > 2 || imp == INVALID_IMP)
     goto not_found;
 
-  if (arch && !arch_id)
-    goto not_found;
-
   if (arch)
     {
+      /* Search for one of the cores in the list. */
+      for (i = 0; aarch64_cpu_data[i].name != NULL; i++)
+	if (aarch64_cpu_data[i].implementer_id == imp
+	    && contains_core_p (cores, aarch64_cpu_data[i].part_no))
+	  {
+	    arch_id = aarch64_cpu_data[i].arch;
+	    break;
+	  }
+      if (!arch_id)
+	goto not_found;
+
       struct aarch64_arch_driver_info* arch_info = get_arch_from_id (arch_id);
 
       /* We got some arch indentifier that's not in aarch64-arches.def?  */
@@ -312,7 +314,15 @@ host_detect_local_cpu (int argc, const c
   /* The simple, non-big.LITTLE case.  */
   else
     {
-      if (aarch64_cpu_data[core_idx].implementer_id != imp)
+      int core_idx = -1;
+      for (i = 0; aarch64_cpu_data[i].name != NULL; i++)
+	if (cores[0] == aarch64_cpu_data[i].part_no
+	    && aarch64_cpu_data[i].implementer_id == imp)
+	  {
+	    core_idx = i;
+	    break;
+	  }
+      if (core_idx == -1)
 	goto not_found;
 
       res = concat ("-m", cpu ? "cpu" : "tune", "=",