* x86-64 can handle overflows in 64 bit multiplications directly, part of resolving #39450

compiler/x86_64/nx64add.pas

@@ -30,8 +30,9 @@ interface
 
     type
        tx8664addnode = class(tx86addnode)
-          procedure second_addordinal; override;
-          procedure second_mul;
+         function use_generic_mul64bit: boolean; override;
+         procedure second_addordinal; override;
+         procedure second_mul;
        end;
 
   implementation
@@ -43,6 +44,11 @@ interface
       cgbase,cgutils,cga,cgobj,hlcgobj,cgx86,
       tgobj;
 
+    function tx8664addnode.use_generic_mul64bit: boolean;
+    begin
+      result:=false;
+    end;
+
 {*****************************************************************************
                                 Addordinal
 *****************************************************************************}