diff --git a/compiler/i386/cpuswtch.pas b/compiler/i386/cpuswtch.pas
index 5893bbe508..b78e073bc0 100644
--- a/compiler/i386/cpuswtch.pas
+++ b/compiler/i386/cpuswtch.pas
@@ -58,7 +58,8 @@ begin
                    end;
                  'a' :
                    begin
-                     UpdateAlignmentStr(Copy(Opt,j+1,255),ParaAlignment);
+                     if not(UpdateAlignmentStr(Copy(Opt,j+1,255),ParaAlignment)) then
+                       IllegalPara(opt);
                      j:=length(Opt);
                    end;
                  'g' : initglobalswitches:=initglobalswitches+[cs_littlesize];