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* [Bug tree-optimization/22199] New: Unnecessary casts for comparison
@ 2005-06-27 15:04 tkoenig at gcc dot gnu dot org
2005-06-27 15:18 ` [Bug tree-optimization/22199] " pinskia at gcc dot gnu dot org
2005-09-24 16:22 ` [Bug tree-optimization/22199] fold does not optimize (int)ABS_EXPR<(long long)(int_var)> pinskia at gcc dot gnu dot org
0 siblings, 2 replies; 6+ messages in thread
From: tkoenig at gcc dot gnu dot org @ 2005-06-27 15:04 UTC (permalink / raw)
To: gcc-bugs
$ cat labs.c
extern long int labs (long int __x) __attribute__ ((__const__));
int main()
{
int a,b;
foo(&a, &b);
if (labs(a) > b)
return 1;
else
return 0;
}
is translated with
$ gcc -O3 -fdump-tree-optimized -S labs.c
into
<bb 0>:
foo (&a, &b);
return (int) (ABS_EXPR <(long int) a> > (long int) b);
The casts aren't necessary in this case.
--
Summary: Unnecessary casts for comparison
Product: gcc
Version: 4.1.0
Status: UNCONFIRMED
Keywords: missed-optimization
Severity: enhancement
Priority: P2
Component: tree-optimization
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: tkoenig at gcc dot gnu dot org
CC: gcc-bugs at gcc dot gnu dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22199
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug tree-optimization/22199] Unnecessary casts for comparison
2005-06-27 15:04 [Bug tree-optimization/22199] New: Unnecessary casts for comparison tkoenig at gcc dot gnu dot org
@ 2005-06-27 15:18 ` pinskia at gcc dot gnu dot org
2005-09-24 16:22 ` [Bug tree-optimization/22199] fold does not optimize (int)ABS_EXPR<(long long)(int_var)> pinskia at gcc dot gnu dot org
1 sibling, 0 replies; 6+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-06-27 15:18 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2005-06-27 15:17 -------
A better example as on 32bit targets long and int are the same size which removes the casts:
extern long long int llabs (long long int __x) __attribute__ ((__const__));
int main()
{
int a,b;
foo(&a, &b);
if (llabs(a) > b)
return 1;
else
return 0;
}
Or just as good:
extern int abs (int __x) __attribute__ ((__const__));
void foo(short *, short*);
int main()
{
short a,b;
foo(&a, &b);
if (abs(a) > b)
return 1;
else
return 0;
}
Though only the first one will have different asm and will be better optimized.
--
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Ever Confirmed| |1
Last reconfirmed|0000-00-00 00:00:00 |2005-06-27 15:17:41
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22199
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug tree-optimization/22199] fold does not optimize (int)ABS_EXPR<(long long)(int_var)>
2005-06-27 15:04 [Bug tree-optimization/22199] New: Unnecessary casts for comparison tkoenig at gcc dot gnu dot org
2005-06-27 15:18 ` [Bug tree-optimization/22199] " pinskia at gcc dot gnu dot org
@ 2005-09-24 16:22 ` pinskia at gcc dot gnu dot org
1 sibling, 0 replies; 6+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-09-24 16:22 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2005-09-24 16:22 -------
Changing the summary to be more reflect what this bug is about.
--
What |Removed |Added
----------------------------------------------------------------------------
OtherBugsDependingO| |19987
nThis| |
Last reconfirmed|2005-06-27 15:17:41 |2005-09-24 16:22:48
date| |
Summary|Unnecessary casts for |fold does not optimize
|comparison |(int)ABS_EXPR<(long
| |long)(int_var)>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22199
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug tree-optimization/22199] fold does not optimize (int)ABS_EXPR<(long long)(int_var)>
[not found] <bug-22199-4@http.gcc.gnu.org/bugzilla/>
2021-06-03 3:35 ` pinskia at gcc dot gnu.org
@ 2021-06-03 3:37 ` pinskia at gcc dot gnu.org
1 sibling, 0 replies; 6+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-06-03 3:37 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=22199
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|--- |9.0
--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Fixed with r9-1281 by the way.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug tree-optimization/22199] fold does not optimize (int)ABS_EXPR<(long long)(int_var)>
[not found] <bug-22199-4@http.gcc.gnu.org/bugzilla/>
@ 2021-06-03 3:35 ` pinskia at gcc dot gnu.org
2021-06-03 3:37 ` pinskia at gcc dot gnu.org
1 sibling, 0 replies; 6+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-06-03 3:35 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=22199
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|--- |FIXED
Status|NEW |RESOLVED
--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
There is ABSU now.
Which we use now:
a.0_1 = a;
_2 = ABSU_EXPR <a.0_1>;
_3 = (long int) _2;
b.1_4 = b;
So fixed.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug tree-optimization/22199] fold does not optimize (int)ABS_EXPR<(long long)(int_var)>
[not found] <bug-22199-10391@http.gcc.gnu.org/bugzilla/>
@ 2005-12-24 20:15 ` pinskia at gcc dot gnu dot org
0 siblings, 0 replies; 6+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-12-24 20:15 UTC (permalink / raw)
To: gcc-bugs
------- Comment #3 from pinskia at gcc dot gnu dot org 2005-12-24 20:15 -------
Hmm, actually this is not really valid to do except when -fwrapv is supplied as
(int)ABS_EXPR<(long long) 0x80000000 > is defined to be 0 but ABS_EXPR<
(int)0x80000000> is undefined.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22199
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2021-06-03 3:37 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2005-06-27 15:04 [Bug tree-optimization/22199] New: Unnecessary casts for comparison tkoenig at gcc dot gnu dot org
2005-06-27 15:18 ` [Bug tree-optimization/22199] " pinskia at gcc dot gnu dot org
2005-09-24 16:22 ` [Bug tree-optimization/22199] fold does not optimize (int)ABS_EXPR<(long long)(int_var)> pinskia at gcc dot gnu dot org
[not found] <bug-22199-10391@http.gcc.gnu.org/bugzilla/>
2005-12-24 20:15 ` pinskia at gcc dot gnu dot org
[not found] <bug-22199-4@http.gcc.gnu.org/bugzilla/>
2021-06-03 3:35 ` pinskia at gcc dot gnu.org
2021-06-03 3:37 ` pinskia at gcc dot gnu.org
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