Re: Interesting performance quirk.

[Martin <martin.dowie@btopenworld.com>]

On Oct 29, 9:59 am, "Peter C. Chapin" <pcc482...@gmail.com> wrote:
> In any event I don't want to "resort" to assembly language or to
> removing the Ada mandated checks (at least not in the final version).

With a bit of care a lot of checks can be avoided or removed by the
compiler. A fairly common example of this wrt loops is:

   type Array_Index_Type is range ...;
   type Array_Type is array (Array_Index_Type) of ...;

   procedure Example (A : Array_Type) is
   begin
      for I in Array_Index_Type loop
         -- Do something with array I - a check is often included
      end loop;
   end Example;

is better written as:

   procedure Example (A : Array_Type) is
   begin
      for I in A'Range loop
         -- Do something with array I - no need for a check
      end loop;
   end Example;

I'm not a language lawyer, so I can't tell if that's compiler
inefficiencies or what the language requires but this was certainly
the behaviour of several compilers I've used***.

Cheers
-- Martin

*** I haven't checked this recently!!! :-)