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* [Bug tree-optimization/115011] New: [14/15 Regression] Missed optimization: (bool) (f ? 1: t) ==> 1 when bool t = (0 >= f) + x;
@ 2024-05-09 12:59 652023330028 at smail dot nju.edu.cn
2024-05-09 14:27 ` [Bug tree-optimization/115011] " hjl.tools at gmail dot com
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: 652023330028 at smail dot nju.edu.cn @ 2024-05-09 12:59 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115011
Bug ID: 115011
Summary: [14/15 Regression] Missed optimization: (bool) (f ? 1:
t) ==> 1 when bool t = (0 >= f) + x;
Product: gcc
Version: 15.0
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 the code below can be optimized as stated in the title,
but gcc -O3 seems to have missed it.
Reduced code:
https://godbolt.org/z/xE6GEEn7j
bool x;
bool fn3(unsigned long long int f) {
bool t = (0 >= f) + x;
return f ? 1: t;
}
GCC -O3:
fn3(unsigned long long):
movzx eax, BYTE PTR x[rip]
cmp rdi, 1
adc eax, 0
test eax, eax
setne al
test rdi, rdi
setne dl
or eax, edx
ret
Expected code (GCC-13.2):
fn3(unsigned long long):
mov eax, 1
ret
Thank you very much for your time and effort! We look forward to hearing from
you.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug tree-optimization/115011] [14/15 Regression] Missed optimization: (bool) (f ? 1: t) ==> 1 when bool t = (0 >= f) + x;
2024-05-09 12:59 [Bug tree-optimization/115011] New: [14/15 Regression] Missed optimization: (bool) (f ? 1: t) ==> 1 when bool t = (0 >= f) + x; 652023330028 at smail dot nju.edu.cn
@ 2024-05-09 14:27 ` hjl.tools at gmail dot com
2024-05-09 14:28 ` pinskia at gcc dot gnu.org
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: hjl.tools at gmail dot com @ 2024-05-09 14:27 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115011
H.J. Lu <hjl.tools at gmail dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |pinskia at gcc dot gnu.org
Target Milestone|--- |14.2
Status|UNCONFIRMED |NEW
Last reconfirmed| |2024-05-09
Ever confirmed|0 |1
--- Comment #1 from H.J. Lu <hjl.tools at gmail dot com> ---
It is caused by r14-1597.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug tree-optimization/115011] [14/15 Regression] Missed optimization: (bool) (f ? 1: t) ==> 1 when bool t = (0 >= f) + x;
2024-05-09 12:59 [Bug tree-optimization/115011] New: [14/15 Regression] Missed optimization: (bool) (f ? 1: t) ==> 1 when bool t = (0 >= f) + x; 652023330028 at smail dot nju.edu.cn
2024-05-09 14:27 ` [Bug tree-optimization/115011] " hjl.tools at gmail dot com
@ 2024-05-09 14:28 ` pinskia at gcc dot gnu.org
2024-05-09 14:50 ` pinskia at gcc dot gnu.org
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: pinskia at gcc dot gnu.org @ 2024-05-09 14:28 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115011
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed|2024-05-09 00:00:00 |
Status|NEW |ASSIGNED
Assignee|unassigned at gcc dot gnu.org |pinskia at gcc dot gnu.org
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed. this was "exposed/caused" by my r14-3486-gd9a0d692ffc695 .
We miss this in previous releases too (LLVM is only able to optimize it for
LLVM 18+):
```
bool x;
bool fn3(unsigned long long int f) {
bool t = (0 >= f) + x;
bool t1 = t | (f != 0);
return t1;
}
```
I will look into this in a few weeks since I suspect it is a minor regression.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug tree-optimization/115011] [14/15 Regression] Missed optimization: (bool) (f ? 1: t) ==> 1 when bool t = (0 >= f) + x;
2024-05-09 12:59 [Bug tree-optimization/115011] New: [14/15 Regression] Missed optimization: (bool) (f ? 1: t) ==> 1 when bool t = (0 >= f) + x; 652023330028 at smail dot nju.edu.cn
2024-05-09 14:27 ` [Bug tree-optimization/115011] " hjl.tools at gmail dot com
2024-05-09 14:28 ` pinskia at gcc dot gnu.org
@ 2024-05-09 14:50 ` pinskia at gcc dot gnu.org
2024-05-09 14:50 ` pinskia at gcc dot gnu.org
2024-05-10 12:27 ` rguenth at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: pinskia at gcc dot gnu.org @ 2024-05-09 14:50 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115011
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Depends on| |104292
--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
The easiest way to fix this is to optimize t_12 in:
```
_1 = f_10(D) == 0;
_2 = (int) _1; //[0,1]
x.0_3 = x;
_4 = (int) x.0_3; //[0,1]
_5 = _2 + _4;
t_12 = _5 != 0;
_7 = f_10(D) != 0;
_14 = _7 | t_12;
```
Into:
``
x.0_3 = x;
_1 = f_10(D) == 0;
t_12 = _1 | x.0_3; // <-- this
_7 = f_10(D) != 0;
_14 = _7 | t_12;
```
Which then will be optimized into true as _1 and _7 are opposites.
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104292
[Bug 104292] (bool)(bool0 + bool1) should be simplified into bool0 | bool1
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug tree-optimization/115011] [14/15 Regression] Missed optimization: (bool) (f ? 1: t) ==> 1 when bool t = (0 >= f) + x;
2024-05-09 12:59 [Bug tree-optimization/115011] New: [14/15 Regression] Missed optimization: (bool) (f ? 1: t) ==> 1 when bool t = (0 >= f) + x; 652023330028 at smail dot nju.edu.cn
` (2 preceding siblings ...)
2024-05-09 14:50 ` pinskia at gcc dot gnu.org
@ 2024-05-09 14:50 ` pinskia at gcc dot gnu.org
2024-05-10 12:27 ` rguenth at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: pinskia at gcc dot gnu.org @ 2024-05-09 14:50 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115011
--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
So depends on PR 104292.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug tree-optimization/115011] [14/15 Regression] Missed optimization: (bool) (f ? 1: t) ==> 1 when bool t = (0 >= f) + x;
2024-05-09 12:59 [Bug tree-optimization/115011] New: [14/15 Regression] Missed optimization: (bool) (f ? 1: t) ==> 1 when bool t = (0 >= f) + x; 652023330028 at smail dot nju.edu.cn
` (3 preceding siblings ...)
2024-05-09 14:50 ` pinskia at gcc dot gnu.org
@ 2024-05-10 12:27 ` rguenth at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: rguenth at gcc dot gnu.org @ 2024-05-10 12:27 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115011
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Priority|P3 |P2
^ permalink raw reply [flat|nested] 6+ messages in thread
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2024-05-09 14:27 ` [Bug tree-optimization/115011] " hjl.tools at gmail dot com
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