[fpc-pascal] A question about sets performance

[Vladimir Zhirov]

Hi,

I'm trying to optimize my CSV parser class, and facing with a bit
unexpected results. I tried to change in-place set declaration
(if ch in [a, b, c] then ...) to reusable set constants 
(if ch in ABCSet then ...), and noticed a slight slowdown.
To check it, I created a simple test application:

const
  cs: set of char = ['a', 'b', 'c', 'd', 'e'];
var
  i: Integer;
  c: Char;
  b: Boolean;
begin
  c := 'a';
  for i := 0 to MaxInt do
  begin
    // A. In-place set declaration
    b := c in ['a', 'b', 'c', 'd', 'e'];

    // B. Set constant
    // b := c in cs;
  end;
end.

I was surprised when B turned out to be almost 3 times
slower than A (~11 vs ~29 sec. on my hardware). This ratio
remains nearly the same regardless of compiler optimization
level.

I'm using FPC 2.4.2 [2010/12/27] for i386 on Linux.

1) Is it expected behavior, or should I create 
   a bug report about it?
2) What way (A or B) are you using in your programs 
   (or would suggest to use in long term)?

Thanks in advance.

--
Vladimir