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From: "Martin Dowie" <martin.dowie@btopenworld.com>
Subject: Re: Optimizing Boundary Checks
Date: Fri, 13 Jun 2003 13:34:17 +0000 (UTC)
Date: 2003-06-13T13:34:17+00:00	[thread overview]
Message-ID: <bccjsp$lid$1@hercules.btinternet.com> (raw)
In-Reply-To: slrnbejegn.in.randhol+abuse@kiuk0152.chembio.ntnu.no

"Preben Randhol" <randhol+abuse@pvv.org> wrote in message
news:slrnbejegn.in.randhol+abuse@kiuk0152.chembio.ntnu.no...
> After reading some posts here lately I have understood that the compiler
> can optimise out boundary checks on say arrays if you do this:

Keyword in the last line is 'can'. I've run across compilers that
will do no optimization (i.e. leave checks in) on code such as:

   for I in My_Type loop
      Make_Call(My_Array (I));
   end loop;

but would take them out if written:

   for I in My_Array'Range loop
      Make_Call(My_Array(I));
   end loop;

Not sure if the checks in the first example would have
disappeared if we'd been allowed to switch compiler
optimizations on...

I guess the you just have to get that assembler listing and
check what each compiler you use does!





  parent reply	other threads:[~2003-06-13 13:34 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-06-13 11:49 Optimizing Boundary Checks Preben Randhol
2003-06-13 12:03 ` Erlo Haugen
2003-06-13 12:38   ` Vinzent Hoefler
2003-06-13 12:47     ` Preben Randhol
2003-06-13 13:28       ` Vinzent Hoefler
2003-06-13 12:42   ` Preben Randhol
2003-06-13 12:48     ` Preben Randhol
2003-06-13 13:28       ` Vinzent Hoefler
2003-06-13 13:56         ` Preben Randhol
2003-06-13 14:42           ` Vinzent Hoefler
2003-06-13 15:25             ` Preben Randhol
2003-06-13 15:34               ` Vinzent Hoefler
2003-06-14 10:45                 ` Preben Randhol
2003-06-14 14:59                   ` James Rogers
2003-06-13 13:33       ` Peter Amey
2003-06-13 13:34 ` Martin Dowie [this message]
2003-06-13 13:48   ` Vinzent Hoefler
2003-06-13 14:37     ` Martin Dowie
2003-06-13 15:12       ` Vinzent Hoefler
2003-06-14  2:01         ` Jeffrey Carter
2003-06-16 11:23           ` Vinzent Hoefler
2003-06-14  8:34         ` Dmitry A. Kazakov
2003-06-14 17:20         ` Robert I. Eachus
2003-06-16 11:23           ` Vinzent Hoefler
2003-06-18 20:58             ` Brian Gaffney
2003-06-13 13:45 ` Dale Stanbrough
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