+ New optimization: Comparisions with evaluate to true or false if the

    constant is outside the range of type bounds of the left expression.
    I.e. "if a>0" evaluates to true if a is declared with type 1..10,
    as all legal values of a are greater than zero.

git-svn-id: trunk@7603 -

compiler/nadd.pas

@@ -173,7 +173,6 @@ implementation
                end;
           end;
 
-
         { both are int constants }
         if (
             (
@@ -382,7 +381,92 @@ implementation
              end;
              result:=t;
              exit;
-          end;
+          end
+        {Match against the ranges, i.e.:
+         var a:1..10;
+         begin
+           if a>0 then
+         ... always evaluates to true. (DM)}
+        else if is_constintnode(left) and (right.resultdef.typ=orddef)
+            {workaround for u64bit bugs} and (Torddef(right.resultdef).ordtype<>u64bit) then
+            begin
+              t:=nil;
+              lv:=Tordconstnode(left).value;
+              with Torddef(right.resultdef) do
+                case nodetype of
+                 ltn:
+                   if lv<low then
+                     t:=Cordconstnode.create(1,booltype,true)
+                   else if lv>=high then
+                     t:=Cordconstnode.create(0,booltype,true);
+                 lten:
+                   if lv<=low then
+                     t:=Cordconstnode.create(1,booltype,true)
+                   else if lv>high then
+                     t:=Cordconstnode.create(0,booltype,true);
+                 gtn:
+                   if lv<=low then
+                     t:=Cordconstnode.create(0,booltype,true)
+                   else if lv>high then
+                     t:=Cordconstnode.create(1,booltype,true);
+                 gten :
+                   if lv<low then
+                     t:=Cordconstnode.create(0,booltype,true)
+                   else if lv>=high then
+                     t:=Cordconstnode.create(1,booltype,true);
+                 equaln:
+                   if (lv<low) or (lv>high) then
+                     t:=Cordconstnode.create(0,booltype,true);
+                 unequaln:
+                   if (lv<low) or (lv>high) then
+                     t:=Cordconstnode.create(1,booltype,true);
+                end;
+              if t<>nil then
+                begin
+                  result:=t;
+                  exit;
+                end
+            end
+          else if (left.resultdef.typ=orddef) and is_constintnode(right)
+            {workaround for u64bit bugs} and (Torddef(left.resultdef).ordtype<>u64bit) then
+            begin
+              t:=nil;
+              rv:=Tordconstnode(right).value;
+              with Torddef(left.resultdef) do
+                case nodetype of
+                 ltn:
+                   if high<rv then
+                     t:=Cordconstnode.create(1,booltype,true)
+                   else if low>=rv then
+                     t:=Cordconstnode.create(0,booltype,true);
+                 lten:
+                   if high<=rv then
+                     t:=Cordconstnode.create(1,booltype,true)
+                   else if low>rv then
+                     t:=Cordconstnode.create(0,booltype,true);
+                 gtn:
+                   if high<=rv then
+                     t:=Cordconstnode.create(0,booltype,true)
+                   else if low>rv then
+                     t:=Cordconstnode.create(1,booltype,true);
+                 gten:
+                   if high<rv then
+                     t:=Cordconstnode.create(0,booltype,true)
+                   else if low>=rv then
+                     t:=Cordconstnode.create(1,booltype,true);
+                 equaln:
+                   if (rv<low) or (rv>high) then
+                     t:=Cordconstnode.create(0,booltype,true);
+                 unequaln:
+                   if (rv<low) or (rv>high) then
+                     t:=Cordconstnode.create(1,booltype,true);
+                end;
+              if t<>nil then
+                begin
+                  result:=t;
+                  exit;
+                end
+            end;
 
         { Add,Sub,Mul with constant 0 or 1?  }
         if is_constintnode(right) and is_integer(left.resultdef) then