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* [Bug tree-optimization/113714] New: [11/12/13/14 Regression] Missed optimization for redundancy computation elimination: -(w+d-x)-x => -(w+d)
@ 2024-02-02 8:31 652023330028 at smail dot nju.edu.cn
2024-02-04 5:32 ` [Bug tree-optimization/113714] " pinskia at gcc dot gnu.org
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: 652023330028 at smail dot nju.edu.cn @ 2024-02-02 8:31 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113714
Bug ID: 113714
Summary: [11/12/13/14 Regression] Missed optimization for
redundancy computation elimination: -(w+d-x)-x =>
-(w+d)
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: 652023330028 at smail dot nju.edu.cn
Target Milestone: ---
Hello, we noticed that x can be eliminated from the calculation of z in the
following code:
c-x => -(w+d-x)-x => -(w+d)
https://godbolt.org/z/MYhGTc4Pv
int x,y,z,w;
void func(int a, int b, int c, int d){
x=a/b - y;
c=-(w+d-x);
z=c-x;
}
But GCC -O3 -fwrapv:
_1 = a_7(D) / b_8(D);
y.0_2 = y;
_3 = _1 - y.0_2;
x = _3;
#Here is the part related to the calculation of z:
w.2_4 = w;
_20 = y.0_2 - w.2_4;
_21 = _20 - d_11(D);
_22 = _3 + _21;
_6 = _22 - _1;
z = _6;
return;
Expected code:
GCC-10.5 -O3 -fwrapv
_1 = a_7(D) / b_8(D);
y.0_2 = y;
_3 = _1 - y.0_2;
x = _3;
#Here is the part related to the calculation of z:
w.2_4 = w;
_5 = w.2_4 + d_11(D);
_6 = -_5;
z = _6;
return;
Thank you very much for your time and effort! We look forward to hearing from
you.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/113714] [11/12/13/14 Regression] Missed optimization for redundancy computation elimination: -(w+d-x)-x => -(w+d)
2024-02-02 8:31 [Bug tree-optimization/113714] New: [11/12/13/14 Regression] Missed optimization for redundancy computation elimination: -(w+d-x)-x => -(w+d) 652023330028 at smail dot nju.edu.cn
@ 2024-02-04 5:32 ` pinskia at gcc dot gnu.org
2024-02-04 5:34 ` pinskia at gcc dot gnu.org
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu.org @ 2024-02-04 5:32 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113714
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Ever confirmed|0 |1
Last reconfirmed| |2024-02-04
Target Milestone|--- |11.5
Keywords| |needs-bisection
Status|UNCONFIRMED |NEW
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/113714] [11/12/13/14 Regression] Missed optimization for redundancy computation elimination: -(w+d-x)-x => -(w+d)
2024-02-02 8:31 [Bug tree-optimization/113714] New: [11/12/13/14 Regression] Missed optimization for redundancy computation elimination: -(w+d-x)-x => -(w+d) 652023330028 at smail dot nju.edu.cn
2024-02-04 5:32 ` [Bug tree-optimization/113714] " pinskia at gcc dot gnu.org
@ 2024-02-04 5:34 ` pinskia at gcc dot gnu.org
2024-02-11 15:20 ` pheeck at gcc dot gnu.org
2024-03-07 20:42 ` law at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu.org @ 2024-02-04 5:34 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113714
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Known to fail|11.1.0 |
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Hmm, for x86_64, it regressed in GCC 11 but for aarch64, it seems like it is
only a regression on the trunk ...
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/113714] [11/12/13/14 Regression] Missed optimization for redundancy computation elimination: -(w+d-x)-x => -(w+d)
2024-02-02 8:31 [Bug tree-optimization/113714] New: [11/12/13/14 Regression] Missed optimization for redundancy computation elimination: -(w+d-x)-x => -(w+d) 652023330028 at smail dot nju.edu.cn
2024-02-04 5:32 ` [Bug tree-optimization/113714] " pinskia at gcc dot gnu.org
2024-02-04 5:34 ` pinskia at gcc dot gnu.org
@ 2024-02-11 15:20 ` pheeck at gcc dot gnu.org
2024-03-07 20:42 ` law at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: pheeck at gcc dot gnu.org @ 2024-02-11 15:20 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113714
Filip Kastl <pheeck at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |aldyh at redhat dot com,
| |pheeck at gcc dot gnu.org
--- Comment #3 from Filip Kastl <pheeck at gcc dot gnu.org> ---
For x86_64, I've bisected the regression to r11-1146-g1396fa5b91cfa0
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/113714] [11/12/13/14 Regression] Missed optimization for redundancy computation elimination: -(w+d-x)-x => -(w+d)
2024-02-02 8:31 [Bug tree-optimization/113714] New: [11/12/13/14 Regression] Missed optimization for redundancy computation elimination: -(w+d-x)-x => -(w+d) 652023330028 at smail dot nju.edu.cn
` (2 preceding siblings ...)
2024-02-11 15:20 ` pheeck at gcc dot gnu.org
@ 2024-03-07 20:42 ` law at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: law at gcc dot gnu.org @ 2024-03-07 20:42 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113714
Jeffrey A. Law <law at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Priority|P3 |P2
CC| |law at gcc dot gnu.org
^ permalink raw reply [flat|nested] 5+ messages in thread
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2024-02-02 8:31 [Bug tree-optimization/113714] New: [11/12/13/14 Regression] Missed optimization for redundancy computation elimination: -(w+d-x)-x => -(w+d) 652023330028 at smail dot nju.edu.cn
2024-02-04 5:32 ` [Bug tree-optimization/113714] " pinskia at gcc dot gnu.org
2024-02-04 5:34 ` pinskia at gcc dot gnu.org
2024-02-11 15:20 ` pheeck at gcc dot gnu.org
2024-03-07 20:42 ` law at gcc dot gnu.org
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