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* [Bug c/17640] New: empty loop not removed after optimization
@ 2004-09-23 21:13 wouter dot vermaelen at pi dot be
2004-09-23 23:01 ` [Bug c/17640] " pinskia at gcc dot gnu dot org
` (11 more replies)
0 siblings, 12 replies; 13+ messages in thread
From: wouter dot vermaelen at pi dot be @ 2004-09-23 21:13 UTC (permalink / raw)
To: gcc-bugs
gcc can optimize this program quite well. However the remaining empty loop is a
bit silly.
int f() { return 1; }
int main() {
int a = 0;
for (int i = 0; i < 100; ++i) {
a += f();
}
return a;
}
> gcc loop.c -O3 -S
main: pushl %ebp
movl %esp, %ebp
subl $8, %esp
andl $-16, %esp
subl $16, %esp
movl $99, %eax
.L7: decl %eax
jns .L7
movl $100, %eax
leave
ret
--
Summary: empty loop not removed after optimization
Product: gcc
Version: 3.4.2
Status: UNCONFIRMED
Severity: enhancement
Priority: P3
Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: wouter dot vermaelen at pi dot be
CC: gcc-bugs at gcc dot gnu dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17640
^ permalink raw reply [flat|nested] 13+ messages in thread
* [Bug c/17640] empty loop not removed after optimization
2004-09-23 21:13 [Bug c/17640] New: empty loop not removed after optimization wouter dot vermaelen at pi dot be
@ 2004-09-23 23:01 ` pinskia at gcc dot gnu dot org
2004-09-23 23:05 ` [Bug tree-optimization/17640] " pinskia at gcc dot gnu dot org
` (10 subsequent siblings)
11 siblings, 0 replies; 13+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2004-09-23 23:01 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2004-09-23 23:01 -------
Confirmed but not the documentation says we don't want this but that has changed.
--
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Ever Confirmed| |1
Last reconfirmed|0000-00-00 00:00:00 |2004-09-23 23:01:45
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17640
^ permalink raw reply [flat|nested] 13+ messages in thread
* [Bug tree-optimization/17640] empty loop not removed after optimization
2004-09-23 21:13 [Bug c/17640] New: empty loop not removed after optimization wouter dot vermaelen at pi dot be
2004-09-23 23:01 ` [Bug c/17640] " pinskia at gcc dot gnu dot org
@ 2004-09-23 23:05 ` pinskia at gcc dot gnu dot org
2004-12-24 2:26 ` pinskia at gcc dot gnu dot org
` (9 subsequent siblings)
11 siblings, 0 replies; 13+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2004-09-23 23:05 UTC (permalink / raw)
To: gcc-bugs
--
What |Removed |Added
----------------------------------------------------------------------------
Component|c |tree-optimization
Keywords| |missed-optimization
Last reconfirmed|2004-09-23 23:01:45 |2004-09-23 23:05:03
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17640
^ permalink raw reply [flat|nested] 13+ messages in thread
* [Bug tree-optimization/17640] empty loop not removed after optimization
2004-09-23 21:13 [Bug c/17640] New: empty loop not removed after optimization wouter dot vermaelen at pi dot be
2004-09-23 23:01 ` [Bug c/17640] " pinskia at gcc dot gnu dot org
2004-09-23 23:05 ` [Bug tree-optimization/17640] " pinskia at gcc dot gnu dot org
@ 2004-12-24 2:26 ` pinskia at gcc dot gnu dot org
2005-01-28 14:26 ` rguenth at tat dot physik dot uni-tuebingen dot de
` (8 subsequent siblings)
11 siblings, 0 replies; 13+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2004-12-24 2:26 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2004-12-24 02:26 -------
*** Bug 18648 has been marked as a duplicate of this bug. ***
--
What |Removed |Added
----------------------------------------------------------------------------
CC| |pluto at pld-linux dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17640
^ permalink raw reply [flat|nested] 13+ messages in thread
* [Bug tree-optimization/17640] empty loop not removed after optimization
2004-09-23 21:13 [Bug c/17640] New: empty loop not removed after optimization wouter dot vermaelen at pi dot be
` (2 preceding siblings ...)
2004-12-24 2:26 ` pinskia at gcc dot gnu dot org
@ 2005-01-28 14:26 ` rguenth at tat dot physik dot uni-tuebingen dot de
2005-01-28 15:18 ` steven at gcc dot gnu dot org
` (7 subsequent siblings)
11 siblings, 0 replies; 13+ messages in thread
From: rguenth at tat dot physik dot uni-tuebingen dot de @ 2005-01-28 14:26 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From rguenth at tat dot physik dot uni-tuebingen dot de 2005-01-28 14:26 -------
One patch for empty-loop removal was posted here by Zdenek
http://gcc.gnu.org/ml/gcc-patches/2004-07/msg01679.html
--
What |Removed |Added
----------------------------------------------------------------------------
CC| |rguenth at tat dot physik
| |dot uni-tuebingen dot de
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17640
^ permalink raw reply [flat|nested] 13+ messages in thread
* [Bug tree-optimization/17640] empty loop not removed after optimization
2004-09-23 21:13 [Bug c/17640] New: empty loop not removed after optimization wouter dot vermaelen at pi dot be
` (3 preceding siblings ...)
2005-01-28 14:26 ` rguenth at tat dot physik dot uni-tuebingen dot de
@ 2005-01-28 15:18 ` steven at gcc dot gnu dot org
2005-05-11 12:58 ` giovannibajo at libero dot it
` (6 subsequent siblings)
11 siblings, 0 replies; 13+ messages in thread
From: steven at gcc dot gnu dot org @ 2005-01-28 15:18 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From steven at gcc dot gnu dot org 2005-01-28 15:18 -------
That patch is just gross. Come on, builtin_maybe_infinite_loop?!
There are better and easier ways to kill dead loops. Like, a loop
optimizer that simply removes dead loops ;-)
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17640
^ permalink raw reply [flat|nested] 13+ messages in thread
* [Bug tree-optimization/17640] empty loop not removed after optimization
2004-09-23 21:13 [Bug c/17640] New: empty loop not removed after optimization wouter dot vermaelen at pi dot be
` (4 preceding siblings ...)
2005-01-28 15:18 ` steven at gcc dot gnu dot org
@ 2005-05-11 12:58 ` giovannibajo at libero dot it
2005-05-11 13:00 ` pinskia at gcc dot gnu dot org
` (5 subsequent siblings)
11 siblings, 0 replies; 13+ messages in thread
From: giovannibajo at libero dot it @ 2005-05-11 12:58 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From giovannibajo at libero dot it 2005-05-11 12:58 -------
This is a most-wanted feature. Are there hope to see a patch landing for 4.1?
Can the patch that Zdenek posted be updated for 4.1? Even if it's gross is
surely better than nothing...
--
What |Removed |Added
----------------------------------------------------------------------------
CC| |rakdver at gcc dot gnu dot
| |org, stevenb at suse dot de
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17640
^ permalink raw reply [flat|nested] 13+ messages in thread
* [Bug tree-optimization/17640] empty loop not removed after optimization
2004-09-23 21:13 [Bug c/17640] New: empty loop not removed after optimization wouter dot vermaelen at pi dot be
` (5 preceding siblings ...)
2005-05-11 12:58 ` giovannibajo at libero dot it
@ 2005-05-11 13:00 ` pinskia at gcc dot gnu dot org
2005-05-11 13:02 ` rguenth at gcc dot gnu dot org
` (4 subsequent siblings)
11 siblings, 0 replies; 13+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-05-11 13:00 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2005-05-11 13:00 -------
I should note that loops with small constants bounds are now removed on the mainline.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17640
^ permalink raw reply [flat|nested] 13+ messages in thread
* [Bug tree-optimization/17640] empty loop not removed after optimization
2004-09-23 21:13 [Bug c/17640] New: empty loop not removed after optimization wouter dot vermaelen at pi dot be
` (6 preceding siblings ...)
2005-05-11 13:00 ` pinskia at gcc dot gnu dot org
@ 2005-05-11 13:02 ` rguenth at gcc dot gnu dot org
2005-05-11 13:14 ` stevenb at suse dot de
` (3 subsequent siblings)
11 siblings, 0 replies; 13+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2005-05-11 13:02 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From rguenth at gcc dot gnu dot org 2005-05-11 13:02 -------
Only because they are completely peeled.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17640
^ permalink raw reply [flat|nested] 13+ messages in thread
* [Bug tree-optimization/17640] empty loop not removed after optimization
2004-09-23 21:13 [Bug c/17640] New: empty loop not removed after optimization wouter dot vermaelen at pi dot be
` (7 preceding siblings ...)
2005-05-11 13:02 ` rguenth at gcc dot gnu dot org
@ 2005-05-11 13:14 ` stevenb at suse dot de
2005-05-11 13:16 ` steven at gcc dot gnu dot org
` (2 subsequent siblings)
11 siblings, 0 replies; 13+ messages in thread
From: stevenb at suse dot de @ 2005-05-11 13:14 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From stevenb at suse dot de 2005-05-11 13:14 -------
Subject: Re: empty loop not removed after optimization
On Wednesday 11 May 2005 14:58, giovannibajo at libero dot it wrote:
> ------- Additional Comments From giovannibajo at libero dot it 2005-05-11
> 12:58 ------- This is a most-wanted feature. Are there hope to see a patch
> landing for 4.1? Can the patch that Zdenek posted be updated for 4.1? Even
> if it's gross is surely better than nothing...
nothing is better than gross.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17640
^ permalink raw reply [flat|nested] 13+ messages in thread
* [Bug tree-optimization/17640] empty loop not removed after optimization
2004-09-23 21:13 [Bug c/17640] New: empty loop not removed after optimization wouter dot vermaelen at pi dot be
` (8 preceding siblings ...)
2005-05-11 13:14 ` stevenb at suse dot de
@ 2005-05-11 13:16 ` steven at gcc dot gnu dot org
2005-06-30 21:48 ` steven at gcc dot gnu dot org
2005-07-12 0:01 ` pinskia at gcc dot gnu dot org
11 siblings, 0 replies; 13+ messages in thread
From: steven at gcc dot gnu dot org @ 2005-05-11 13:16 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From steven at gcc dot gnu dot org 2005-05-11 13:15 -------
I'll hack up something.
--
What |Removed |Added
----------------------------------------------------------------------------
CC|stevenb at suse dot de |
AssignedTo|unassigned at gcc dot gnu |steven at gcc dot gnu dot
|dot org |org
Status|NEW |ASSIGNED
Last reconfirmed|2005-05-07 19:58:03 |2005-05-11 13:15:59
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17640
^ permalink raw reply [flat|nested] 13+ messages in thread
* [Bug tree-optimization/17640] empty loop not removed after optimization
2004-09-23 21:13 [Bug c/17640] New: empty loop not removed after optimization wouter dot vermaelen at pi dot be
` (9 preceding siblings ...)
2005-05-11 13:16 ` steven at gcc dot gnu dot org
@ 2005-06-30 21:48 ` steven at gcc dot gnu dot org
2005-07-12 0:01 ` pinskia at gcc dot gnu dot org
11 siblings, 0 replies; 13+ messages in thread
From: steven at gcc dot gnu dot org @ 2005-06-30 21:48 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From steven at gcc dot gnu dot org 2005-06-30 21:48 -------
Zdenek has a patch:
http://gcc.gnu.org/ml/gcc-patches/2005-06/msg02270.html
--
What |Removed |Added
----------------------------------------------------------------------------
AssignedTo|steven at gcc dot gnu dot |unassigned at gcc dot gnu
|org |dot org
Status|ASSIGNED |NEW
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17640
^ permalink raw reply [flat|nested] 13+ messages in thread
* [Bug tree-optimization/17640] empty loop not removed after optimization
2004-09-23 21:13 [Bug c/17640] New: empty loop not removed after optimization wouter dot vermaelen at pi dot be
` (10 preceding siblings ...)
2005-06-30 21:48 ` steven at gcc dot gnu dot org
@ 2005-07-12 0:01 ` pinskia at gcc dot gnu dot org
11 siblings, 0 replies; 13+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-07-12 0:01 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2005-07-12 00:01 -------
Fixed in 4.1.0.
--
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution| |FIXED
Target Milestone|--- |4.1.0
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17640
^ permalink raw reply [flat|nested] 13+ messages in thread
end of thread, other threads:[~2005-07-12 0:01 UTC | newest]
Thread overview: 13+ messages (download: mbox.gz / follow: Atom feed)
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2004-09-23 21:13 [Bug c/17640] New: empty loop not removed after optimization wouter dot vermaelen at pi dot be
2004-09-23 23:01 ` [Bug c/17640] " pinskia at gcc dot gnu dot org
2004-09-23 23:05 ` [Bug tree-optimization/17640] " pinskia at gcc dot gnu dot org
2004-12-24 2:26 ` pinskia at gcc dot gnu dot org
2005-01-28 14:26 ` rguenth at tat dot physik dot uni-tuebingen dot de
2005-01-28 15:18 ` steven at gcc dot gnu dot org
2005-05-11 12:58 ` giovannibajo at libero dot it
2005-05-11 13:00 ` pinskia at gcc dot gnu dot org
2005-05-11 13:02 ` rguenth at gcc dot gnu dot org
2005-05-11 13:14 ` stevenb at suse dot de
2005-05-11 13:16 ` steven at gcc dot gnu dot org
2005-06-30 21:48 ` steven at gcc dot gnu dot org
2005-07-12 0:01 ` pinskia at gcc dot gnu dot org
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