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* [Bug tree-optimization/18832] New: missed jump threading with ||
@ 2004-12-04 19:31 pinskia at gcc dot gnu dot org
2004-12-04 19:43 ` [Bug tree-optimization/18832] " pinskia at gcc dot gnu dot org
` (4 more replies)
0 siblings, 5 replies; 7+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2004-12-04 19:31 UTC (permalink / raw)
To: gcc-bugs
I was messing around with trying to find compile time regressions.
The following 3 functions should produce the same asm.
int f0(int c, int a, int b)
{
if (a == 0 || b == 0) c++;
if (a == 0 || b == 0) c++;
return c;
}
int f1(int c,int a, int b)
{
if (a == 0) goto L1;
if (b == 0) goto L1; else goto L5;
L1:
c++;
L5:
if (a == 0) goto L2;
if (b == 0) goto L2; else goto L3;
L2:
c++;
L3:
return c;
}
int f2(int c,int a, int b)
{
if (a == 0) goto L1;
if (b == 0) goto L1; else goto L5;
L1:
c+=2;
L5:
return c;
}
--
Summary: missed jump threading with ||
Product: gcc
Version: 4.0.0
Status: UNCONFIRMED
Keywords: missed-optimization
Severity: enhancement
Priority: P2
Component: tree-optimization
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: pinskia at gcc dot gnu dot org
CC: gcc-bugs at gcc dot gnu dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18832
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug tree-optimization/18832] missed jump threading with ||
2004-12-04 19:31 [Bug tree-optimization/18832] New: missed jump threading with || pinskia at gcc dot gnu dot org
@ 2004-12-04 19:43 ` pinskia at gcc dot gnu dot org
2004-12-05 16:16 ` pinskia at gcc dot gnu dot org
` (3 subsequent siblings)
4 siblings, 0 replies; 7+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2004-12-04 19:43 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2004-12-04 19:43 -------
Oh and this one too:
int f3(int c,int a, int b)
{
if (a== 0||b==0) c+=2;
return c;
}
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18832
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug tree-optimization/18832] missed jump threading with ||
2004-12-04 19:31 [Bug tree-optimization/18832] New: missed jump threading with || pinskia at gcc dot gnu dot org
2004-12-04 19:43 ` [Bug tree-optimization/18832] " pinskia at gcc dot gnu dot org
@ 2004-12-05 16:16 ` pinskia at gcc dot gnu dot org
2005-02-15 1:26 ` law at redhat dot com
` (2 subsequent siblings)
4 siblings, 0 replies; 7+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2004-12-05 16:16 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2004-12-05 16:16 -------
Confirmed.
--
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Ever Confirmed| |1
Last reconfirmed|0000-00-00 00:00:00 |2004-12-05 16:16:12
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18832
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug tree-optimization/18832] missed jump threading with ||
2004-12-04 19:31 [Bug tree-optimization/18832] New: missed jump threading with || pinskia at gcc dot gnu dot org
2004-12-04 19:43 ` [Bug tree-optimization/18832] " pinskia at gcc dot gnu dot org
2004-12-05 16:16 ` pinskia at gcc dot gnu dot org
@ 2005-02-15 1:26 ` law at redhat dot com
2005-04-23 1:08 ` law at redhat dot com
2005-04-25 18:20 ` pinskia at gcc dot gnu dot org
4 siblings, 0 replies; 7+ messages in thread
From: law at redhat dot com @ 2005-02-15 1:26 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From law at redhat dot com 2005-02-14 20:49 -------
We get the code we want for f0, f2 and f3 with the updated thread selection
code. There's still some lameness in f1 though.
--
What |Removed |Added
----------------------------------------------------------------------------
CC| |law at redhat dot com
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18832
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug tree-optimization/18832] missed jump threading with ||
2004-12-04 19:31 [Bug tree-optimization/18832] New: missed jump threading with || pinskia at gcc dot gnu dot org
` (2 preceding siblings ...)
2005-02-15 1:26 ` law at redhat dot com
@ 2005-04-23 1:08 ` law at redhat dot com
2005-04-25 18:20 ` pinskia at gcc dot gnu dot org
4 siblings, 0 replies; 7+ messages in thread
From: law at redhat dot com @ 2005-04-23 1:08 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From law at redhat dot com 2005-04-23 01:08 -------
The threading issues in f0 have been addressed. Some simple code hoisting would
make f0 slightly better from a code size standpoint, but probably wouldn't
help runtime.
The lameness in f1 isn't really a jump threading problem. We have a merge
point before the second pair of tests which is going to make it damn near
impossible to track the values well enough to optimize this code. This
isn't a jump threading problem.
f2 and f3 look good.
Basically there's no jump threading issues left here.
(In reply to comment #1)
> Oh and this one too:
> int f3(int c,int a, int b)
> {
> if (a== 0||b==0) c+=2;
> return c;
> }
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18832
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug tree-optimization/18832] missed jump threading with ||
2004-12-04 19:31 [Bug tree-optimization/18832] New: missed jump threading with || pinskia at gcc dot gnu dot org
` (3 preceding siblings ...)
2005-04-23 1:08 ` law at redhat dot com
@ 2005-04-25 18:20 ` pinskia at gcc dot gnu dot org
4 siblings, 0 replies; 7+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-04-25 18:20 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2005-04-25 18:20 -------
They all produce the same asm on PPC now, thanks.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18832
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug tree-optimization/18832] missed jump threading with ||
[not found] <bug-18832-4@http.gcc.gnu.org/bugzilla/>
@ 2011-03-17 23:14 ` law at redhat dot com
0 siblings, 0 replies; 7+ messages in thread
From: law at redhat dot com @ 2011-03-17 23:14 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18832
Jeffrey A. Law <law at redhat dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
CC| |law at redhat dot com
Resolution| |FIXED
--- Comment #6 from Jeffrey A. Law <law at redhat dot com> 2011-03-17 23:10:16 UTC ---
Fixed long ago.
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2011-03-17 23:10 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2004-12-04 19:31 [Bug tree-optimization/18832] New: missed jump threading with || pinskia at gcc dot gnu dot org
2004-12-04 19:43 ` [Bug tree-optimization/18832] " pinskia at gcc dot gnu dot org
2004-12-05 16:16 ` pinskia at gcc dot gnu dot org
2005-02-15 1:26 ` law at redhat dot com
2005-04-23 1:08 ` law at redhat dot com
2005-04-25 18:20 ` pinskia at gcc dot gnu dot org
[not found] <bug-18832-4@http.gcc.gnu.org/bugzilla/>
2011-03-17 23:14 ` law at redhat dot com
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