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From: Robert A Duff <bobduff@world.std.com>
Subject: Re: Pointer Arithmetic (was: Wanted: Ada STL....)
Date: 1999/02/03
Date: 1999-02-03T00:00:00+00:00	[thread overview]
Message-ID: <wccu2x32uz5.fsf@world.std.com> (raw)
In-Reply-To: 799f5t$7je$1@nnrp1.dejanews.com

robert_dewar@my-dejanews.com writes:

> The design of C in general is effective in allowing the
> user to do some optimization when using a completely stupid
> compiler that does no optimization at all. For example, the
> register declaration is in this category.

True, but to be fair, both compiler and hardware technology have changed
somewhat since C was designed.

> But with a modern optimizing compiler, the excessively low
             ^^^^^^
> level of C code (in particular its over-reliance on
> explicit pointers) is counter productive

Indeed.

>... (it is interesting
> to note that most modern optimizing C compilers simply
> ignore the register declaration, they can do a better job
> than the programmer of figuring out what to keep in
> registers), but these same optimizing compilers cannot undo
> the (mis)use of pointer arithmetic for, e.g. array
> referencing.

True for locals and parameters.  I know of a couple of modern C
compilers that obey the "register" keyword when the variable is not
local to a function.  This can be an efficiency win in some kinds of
programs.

- Bob
-- 
Change robert to bob to get my real email address.  Sorry.




  reply	other threads:[~1999-02-03  0:00 UTC|newest]

Thread overview: 102+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
1999-01-31  0:00 Wanted: Ada STL. Reward: Ada's Future Alexy V Khrabrov
1999-01-31  0:00 ` Simon Wright
1999-02-01  0:00 ` Matthew Heaney
1999-02-01  0:00   ` Alexy V Khrabrov
1999-02-01  0:00     ` Matthew Heaney
1999-02-01  0:00       ` Jeff Carter
1999-02-01  0:00 ` Brian Rogoff
1999-02-01  0:00   ` Ehud Lamm
1999-02-02  0:00     ` Pointer Arithmetic (was: Wanted: Ada STL....) adam
1999-02-02  0:00       ` William Clodius
1999-02-03  0:00         ` adam
1999-02-03  0:00           ` Nick Roberts
1999-02-03  0:00           ` William Clodius
1999-02-03  0:00           ` robert_dewar
1999-02-03  0:00             ` Jean-Pierre Rosen
1999-02-03  0:00       ` robert_dewar
1999-02-03  0:00       ` Nick Roberts
1999-02-03  0:00         ` robert_dewar
1999-02-03  0:00           ` Robert A Duff [this message]
1999-02-02  0:00     ` Wanted: Ada STL. Reward: Ada's Future Brian Rogoff
1999-02-02  0:00       ` robert_dewar
1999-02-04  0:00         ` Ehud Lamm
1999-02-03  0:00       ` John English
1999-02-03  0:00         ` Matthew Heaney
1999-02-03  0:00           ` Brian Rogoff
1999-02-04  0:00             ` Stephen Leake
1999-02-04  0:00               ` Hyman Rosen
1999-02-05  0:00                 ` Stephen Leake
1999-02-05  0:00                   ` Hyman Rosen
1999-02-04  0:00               ` Brian Rogoff
1999-02-05  0:00                 ` Stephen Leake
1999-02-05  0:00                   ` Brian Rogoff
1999-02-04  0:00               ` Matthew Heaney
1999-02-05  0:00               ` John English
1999-02-05  0:00                 ` Brian Rogoff
1999-02-06  0:00                   ` Matthew Heaney
1999-02-05  0:00                 ` Tucker Taft
1999-02-05  0:00                   ` Richard D Riehle
1999-02-05  0:00                   ` Brian Rogoff
1999-02-05  0:00           ` John English
1999-02-05  0:00           ` Nick Roberts
1999-02-04  0:00         ` Ehud Lamm
1999-02-04  0:00           ` Brian Rogoff
1999-02-05  0:00             ` Matthew Heaney
1999-02-05  0:00               ` Brian Rogoff
1999-02-08  0:00                 ` John English
1999-02-04  0:00           ` Pat Rogers
1999-02-04  0:00             ` Larry Kilgallen
1999-02-04  0:00               ` Pat Rogers
1999-02-04  0:00                 ` Larry Kilgallen
1999-02-05  0:00                   ` robert_dewar
1999-02-05  0:00                     ` Larry Kilgallen
1999-02-05  0:00                     ` Tom Moran
1999-02-05  0:00                       ` dewar
1999-02-05  0:00                         ` Tom Moran
1999-02-05  0:00                           ` dewar
1999-02-05  0:00                             ` dennison
1999-02-06  0:00                               ` dewar
1999-02-08  0:00                                 ` dennison
1999-02-08  0:00                                   ` robert_dewar
1999-02-08  0:00                                     ` dennison
1999-02-09  0:00                                       ` robert_dewar
1999-02-09  0:00                                         ` dennison
1999-02-09  0:00                                     ` Nick Roberts
1999-02-07  0:00                               ` Simon Wright
1999-02-08  0:00                               ` Corey Minyard
1999-02-08  0:00                                 ` Open Source Licensing (was: Wanted: Ada STL. Reward: Ada's Future) dennison
1999-02-08  0:00                                   ` Corey Minyard
1999-02-09  0:00                                     ` dennison
1999-02-09  0:00                                       ` Corey Minyard
1999-02-09  0:00                                     ` robert_dewar
1999-02-09  0:00                                       ` Corey Minyard
1999-02-09  0:00                                 ` Wanted: Ada STL. Reward: Ada's Future robert_dewar
1999-02-09  0:00                                   ` dennison
1999-02-10  0:00                                     ` robert_dewar
1999-02-07  0:00                           ` Simon Wright
     [not found]                     ` <36ba730b.35540068@ <79fmg1$fn0$1@nnrp1.dejanews.com>
1999-02-06  0:00                       ` Larry Kilgallen
1999-02-05  0:00                 ` robert_dewar
1999-02-05  0:00               ` robert_dewar
1999-02-05  0:00                 ` Larry Kilgallen
1999-02-05  0:00                   ` robert_dewar
     [not found]                     ` <79f24e$t14 <36BB4162.52FC6D9F@averstar.com>
1999-02-05  0:00                       ` robert_dewar
1999-02-05  0:00                       ` dennison
1999-02-05  0:00                     ` dennison
1999-02-05  0:00                       ` robert_dewar
1999-02-05  0:00                         ` dennison
1999-02-06  0:00                       ` Nick Roberts
1999-02-05  0:00                     ` Tucker Taft
1999-02-04  0:00           ` Al Christians
1999-02-05  0:00           ` John English
1999-02-09  0:00             ` micro_ada
1999-02-05  0:00         ` Nick Roberts
1999-02-08  0:00           ` John English
1999-02-02  0:00     ` Richard D Riehle
1999-02-03  0:00       ` robert_dewar
1999-02-01  0:00 ` dennison
1999-02-01  0:00 ` Jerry van Dijk
1999-02-01  0:00   ` Marin David Condic
1999-02-01  0:00 ` Stanley R. Allen
1999-02-01  0:00 ` Jeff Carter
1999-02-08  0:00   ` Michael F Brenner
1999-02-05  0:00 ` Corey Minyard
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