diff --git a/compiler/nadd.pas b/compiler/nadd.pas
index a5b883a1ca..ca1e390ab3 100644
--- a/compiler/nadd.pas
+++ b/compiler/nadd.pas
@@ -477,7 +477,7 @@ implementation
 
 
       var
-        t       , vl: tnode;
+        t       , vl, hp: tnode;
         lt,rt   : tnodetype;
         hdef,
         rd,ld   : tdef;
@@ -727,6 +727,58 @@ implementation
                   else
                     ;
                 end;
+              end
+            { try to fold
+                          op
+                         /  \
+                       op  const1
+                      /  \
+                  const2 val
+            }
+            else if left.nodetype=nodetype then
+              begin
+                if is_constintnode(taddnode(left).left) then
+                  begin
+                    case left.nodetype of
+                      xorn,
+                      addn,
+                      andn,
+                      orn,
+                      muln:
+                        begin
+                          hp:=right;
+                          right:=taddnode(left).right;
+                          taddnode(left).right:=hp;
+                          left:=left.simplify(false);
+                          result:=getcopy;
+                          result.resultdef:=nil;
+                          do_typecheckpass(result);
+                        end;
+                      else
+                        ;
+                    end;
+                  end
+                else if is_constintnode(taddnode(left).right) then
+                  begin
+                    case left.nodetype of
+                      xorn,
+                      addn,
+                      andn,
+                      orn,
+                      muln:
+                        begin
+                          hp:=right;
+                          right:=taddnode(left).left;
+                          taddnode(left).left:=hp;
+                          left:=left.simplify(false);
+                          result:=getcopy;
+                          result.resultdef:=nil;
+                          do_typecheckpass(result);
+                        end;
+                      else
+                        ;
+                    end;
+                  end
               end;
             if assigned(result) then
               exit;
@@ -759,11 +811,7 @@ implementation
                     ;
                 end;
               end
-{$ifdef VER2_2}
-            else if (tordconstnode(left).value.svalue = -1) and (tordconstnode(left).value.signed) then
-{$else}
             else if tordconstnode(left).value = -1 then
-{$endif}
               begin
                 case nodetype of
                   muln:
@@ -771,6 +819,58 @@ implementation
                   else
                     ;
                 end;
+              end
+            { try to fold
+                          op
+                         /  \
+                     const1  op
+                            /  \
+                        const2 val
+            }
+            else if right.nodetype=nodetype then
+              begin
+                if is_constintnode(taddnode(right).left) then
+                  begin
+                    case right.nodetype of
+                      xorn,
+                      addn,
+                      andn,
+                      orn,
+                      muln:
+                        begin
+                          hp:=left;
+                          left:=taddnode(right).right;
+                          taddnode(right).right:=hp;
+                          right:=right.simplify(false);
+                          result:=getcopy;
+                          result.resultdef:=nil;
+                          do_typecheckpass(result);
+                        end;
+                      else
+                        ;
+                    end;
+                  end
+                else if is_constintnode(taddnode(right).right) then
+                  begin
+                    case right.nodetype of
+                      xorn,
+                      addn,
+                      andn,
+                      orn,
+                      muln:
+                        begin
+                          hp:=left;
+                          left:=taddnode(right).left;
+                          taddnode(right).left:=hp;
+                          right:=right.simplify(false);
+                          result:=getcopy;
+                          result.resultdef:=nil;
+                          do_typecheckpass(result);
+                        end;
+                      else
+                        ;
+                    end;
+                  end
               end;
             if assigned(result) then
               exit;