i386.c (override_options): Pick a 64-bit CPU for the default tuning if TARGET_64BIT.

	* config/i386/i386.c (override_options): Pick a 64-bit CPU
	for the default tuning if TARGET_64BIT.

From-SVN: r84470

gcc/ChangeLog

+2004-07-10  Daniel Jacobowitz  <dan@debian.org>
+
+	* config/i386/i386.c (override_options): Pick a 64-bit CPU
+	for the default tuning if TARGET_64BIT.
+
 2004-07-10  Richard Henderson  <rth@redhat.com>
 
 	* builtins.c (std_gimplify_va_arg_expr): Widen align/boundary

gcc/config/i386/i386.c

@@ -1097,6 +1097,8 @@ void
 override_options (void)
 {
   int i;
+  int ix86_tune_defaulted = 0;
+
   /* Comes from final.c -- no real reason to change it.  */
 #define MAX_CODE_ALIGN 16
 
@@ -1221,7 +1223,10 @@ override_options (void)
   if (!ix86_tune_string && ix86_arch_string)
     ix86_tune_string = ix86_arch_string;
   if (!ix86_tune_string)
-    ix86_tune_string = cpu_names [TARGET_CPU_DEFAULT];
+    {
+      ix86_tune_string = cpu_names [TARGET_CPU_DEFAULT];
+      ix86_tune_defaulted = 1;
+    }
   if (!ix86_arch_string)
     ix86_arch_string = TARGET_64BIT ? "x86-64" : "i386";
 
@@ -1293,7 +1298,20 @@ override_options (void)
 	if (processor_alias_table[i].flags & PTA_PREFETCH_SSE)
 	  x86_prefetch_sse = true;
 	if (TARGET_64BIT && !(processor_alias_table[i].flags & PTA_64BIT))
-	  error ("CPU you selected does not support x86-64 instruction set");
+	  {
+	    if (ix86_tune_defaulted)
+	      {
+		ix86_tune_string = "x86-64";
+		for (i = 0; i < pta_size; i++)
+		  if (! strcmp (ix86_tune_string,
+				processor_alias_table[i].name))
+		    break;
+		ix86_tune = processor_alias_table[i].processor;
+	      }
+	    else
+	      error ("CPU you selected does not support x86-64 "
+		     "instruction set");
+	  }
 	break;
       }