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From: Sam <sah@softcardsystems.com>
To: <9fans@cse.psu.edu>
Subject: Re: [9fans] how to avoid a memset() optimization
Date: Thu, 14 Nov 2002 08:20:24 -0500	[thread overview]
Message-ID: <Pine.LNX.4.30.0211140803070.9338-100000@athena> (raw)
In-Reply-To: <3DD35C73.8090404@null.net>

> Do you really want the compiler to always generate code
> 	MOV	R1,#0
> 	MOV	R2,#0
> 	AND	R2,R1
> 	MOV	R2,X(SP)

Yes, yes, and yes.  Optimizations which intelligently manage
register allocation are about as far as *I* appreciate.  Do
precisely what I say, and no less.  If I write poor code,
boo hoo for me.  Heavily optimizing compilers will *never*
make all coders equal and generally cause more headaches
than they're worth.

I do appreciate some warnings (ie if I forget to initialize
a variable to zero before I use it), but some of them are
just irritating.  Brantley looked over my shoulder a while
back and wondered why I was typing:

	if((m=fn())) {
		...
	}

saying, "what's with the extra parenthesis?"  "Oh, gcc complains
that I should surround assignment values used as a truth statement
and I've just incorporated it by habit to shut it up."

I hadn't even realized I was permitting gcc to define my style.
In essence, by permitting mad optimizations and then having to
do backflips just to keep the compiler from optimizing away
our real intentions, we're doing the same thing.  I hardly see
this as useful.

Cheers,

Sam




  reply	other threads:[~2002-11-14 13:20 UTC|newest]

Thread overview: 104+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-11-14  6:53 Russ Cox
2002-11-14 10:22 ` Douglas A. Gwyn
2002-11-14 13:20   ` Sam [this message]
2002-11-14 15:20     ` Scott Schwartz
2002-11-14 15:26       ` Boyd Roberts
2002-11-14 15:34         ` plan9
2002-11-14 15:59           ` Sam
2002-11-14 18:57         ` Steve Kilbane
2002-11-15 10:51           ` Douglas A. Gwyn
2002-11-14 15:50       ` Dan Cross
2002-11-14 17:21         ` Douglas A. Gwyn
2002-11-14 18:51           ` Dan Cross
2002-11-14 15:50     ` Douglas A. Gwyn
2002-11-19  7:20 ` Roman V. Shaposhnick
     [not found] <sah@softcardsystems.com>
2003-02-15 14:30 ` [9fans] presentation preparation Sam
2003-02-15 19:37   ` Scott Schwartz
2003-02-15 19:48     ` andrey mirtchovski
2003-02-27  9:35       ` Ralph Corderoy
2003-02-28 18:44         ` [9fans] union directories Jack Johnson
2003-02-28 18:53           ` Russ Cox
2003-03-04  9:44           ` Adrian Tritschler
2003-02-15 20:49   ` [9fans] presentation preparation Richard Miller
2003-02-17 15:00   ` Russ Cox
2003-02-17 16:25     ` Fco.J.Ballesteros
  -- strict thread matches above, loose matches on Subject: below --
2003-01-06 10:47 [9fans] how to avoid a memset() optimization nigel
2003-01-06 11:15 ` Geoff Collyer
2002-11-19 14:32 presotto
2002-11-20  7:24 ` Tomas
2002-11-20 16:38   ` Douglas A. Gwyn
2002-11-19  8:21 Fco.J.Ballesteros
2002-11-18 21:36 Joel Salomon
2002-11-18 20:42 Andrew Simmons
2002-11-18 14:19 C H Forsyth
2002-11-15  1:56 Dennis Ritchie
2002-11-15 10:51 ` Douglas A. Gwyn
2002-11-15 12:03 ` Boyd Roberts
2002-11-14 18:55 jmk
2002-11-14 22:23 ` Steve Kilbane
2002-11-14 18:17 presotto
2002-11-14 18:11 Joel Salomon
2002-11-14 18:26 ` William Josephson
2002-11-14 17:44 rog
2002-11-15 10:50 ` Douglas A. Gwyn
2002-11-14 17:28 Russ Cox
2002-11-14 16:47 presotto
2002-11-15 10:50 ` Douglas A. Gwyn
2002-11-15 16:51   ` William Josephson
2002-11-18 10:38     ` Douglas A. Gwyn
2002-11-18 12:34       ` Ronald G. Minnich
2002-11-19  7:38 ` Roman V. Shaposhnick
2002-11-20  9:47   ` Douglas A. Gwyn
2002-11-21 20:55     ` Roman V. Shaposhnick
2002-11-22  9:59       ` Douglas A. Gwyn
2003-01-06 10:18   ` Ralph Corderoy
2003-01-06 15:42     ` Sam
2003-01-06 15:49       ` Russ Cox
2003-01-06 15:58         ` David Presotto
2003-01-06 16:02         ` Sam
     [not found] <nemo@plan9.escet.urjc.es>
2002-11-14 15:38 ` Fco.J.Ballesteros
2002-11-14 16:24   ` Scott Schwartz
2002-11-14  2:48 Dennis Ritchie
2002-11-14  4:23 ` Ronald G. Minnich
2002-11-13 18:58 Rob `Commander' Pike
2002-11-13 14:40 C H Forsyth
2002-11-13 15:54 ` rob pike
2002-11-13 16:05   ` andrey mirtchovski
2002-11-13 16:32   ` Ronald G. Minnich
2002-11-14 10:21     ` Douglas A. Gwyn
2002-11-14 17:07       ` Ronald G. Minnich
2002-11-22  9:59     ` Clint Olsen
2002-11-13 16:56   ` William K. Josephson
2002-11-14 10:21     ` Douglas A. Gwyn
2002-11-14 16:48       ` William Josephson
2002-11-14 10:21   ` Douglas A. Gwyn
2002-11-14 14:46     ` Dan Cross
2002-11-14 16:59       ` Douglas A. Gwyn
2002-11-14 18:31         ` Tad Hunt
2002-11-15 10:50           ` Douglas A. Gwyn
2002-11-18 14:27         ` Aharon Robbins
2002-11-13 14:14 Skip Tavakkolian
2002-11-13 13:55 rog
2002-11-13 13:38 Skip Tavakkolian
2002-11-13 16:25 ` Boyd Roberts
2002-11-13 10:43 C H Forsyth
2002-11-14 10:21 ` Douglas A. Gwyn
2002-11-13  6:52 Geoff Collyer
2002-11-13 10:13 ` Boyd Roberts
2002-11-13  6:34 Andrew Simmons
2002-11-13  6:43 ` Doc Shipley
2002-11-13  1:47 Russ Cox
2002-11-13 10:16 ` Douglas A. Gwyn
2002-11-14  1:46 ` Roman V. Shaposhnick
2002-11-14  1:52   ` William Josephson
2002-11-14  6:42     ` Roman V. Shaposhnick
2002-11-13  0:31 Russ Cox
2002-11-13  1:26 ` Roman V. Shaposhnick
2002-11-13 10:15   ` Douglas A. Gwyn
2002-11-14  1:42     ` Roman V. Shaposhnick
2002-11-13 10:15 ` Douglas A. Gwyn
2002-11-13  0:20 presotto
2002-11-12 22:42 Roman V. Shaposhnick
2002-07-16 15:53 [9fans] useful language extension, or no? rob pike, esq.
2002-07-16 15:05 ` Sam
2002-07-16 21:29   ` Steve Kilbane

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