Re: Assuming optimization? What is best of these code alternatives?

[reinkor <reinkor@gmail.com>]

OK, thanks so far. I may have oversimplified in my example.
The expression "i1 + i2" may be replaced by something more complex such
as an ordered set (container). Here is a copy from my "real code" where A and B
are (container) ordered sets. Is it any point to store the result from
the following set operations before entering the loops here ?

         AandB := A and B;
         AmB   := A - B;
         AmC   := A - C;
         BmA   := B - A;  -- obs "set minus" = { x |  x \in B and x not \in A)
         CmA   := C - A;

         for j in pos1.j + 1 .. pos2.j - 1 loop
         for i in pos1.i + 1 .. pos2.i - 1 loop
            Bpos := (i,j) + Br0;
            Cpos := (i,j) + Cr0;
            img2(i,j) := RelInf(i,j,img1,AmB);
            if not Rel(img2(i,j),img2(Bpos.i,Bpos.j)) then
               if (for some E of BmA => Rel(img1(i + E.i,j+E.j),img2(Bpos.i,Bpos.j))) then
                  img2(i,j) := RelInf(i,j,img1,AmC);
                  if not Rel(img2(i,j),img2(Cpos.i,Cpos.j)) then
                     if (for some E of CmA => Rel(img1(i + E.i,j+E.j),img2(Cpos.i,Cpos.j))) then
                        img2(i,j) :=  RelInf(i,j,img1,AandB);
                     else
                        img2(i,j) := img2(Cpos.i,Cpos.j);
                     end if;
                  end if;
               else
                  img2(i,j) :=  img2(Bpos.i,Bpos.j);
               end if;
            end if;
         end loop;
         end loop;