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* [Bug tree-optimization/110922] New: `(a == b) & (a == c) & (b != c)` is not optimized to false
@ 2023-08-06 17:18 pinskia at gcc dot gnu.org
2023-08-06 17:21 ` [Bug tree-optimization/110922] " pinskia at gcc dot gnu.org
2023-08-21 7:46 ` pinskia at gcc dot gnu.org
0 siblings, 2 replies; 3+ messages in thread
From: pinskia at gcc dot gnu.org @ 2023-08-06 17:18 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110922
Bug ID: 110922
Summary: `(a == b) & (a == c) & (b != c)` is not optimized to
false
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Keywords: missed-optimization
Severity: enhancement
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: pinskia at gcc dot gnu.org
Target Milestone: ---
I noticed this while looking at PR 110919:
```
int f(int a, int b)
{
_Bool t = a == b;
_Bool t1 = a == 0;
_Bool t2 = b != 0;
return t&t1&t2;
}
```
is not optimized to false.
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug tree-optimization/110922] `(a == b) & (a == c) & (b != c)` is not optimized to false
2023-08-06 17:18 [Bug tree-optimization/110922] New: `(a == b) & (a == c) & (b != c)` is not optimized to false pinskia at gcc dot gnu.org
@ 2023-08-06 17:21 ` pinskia at gcc dot gnu.org
2023-08-21 7:46 ` pinskia at gcc dot gnu.org
1 sibling, 0 replies; 3+ messages in thread
From: pinskia at gcc dot gnu.org @ 2023-08-06 17:21 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110922
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
I think you need the following 3 patterns, there might be more though:
(simplify
(bit_and:c
(bit_and:c
(eq:c @0 @1)
(eq:c @0 @2)
)
(ne:c @1 @2)
)
( { falsevalue; } )
)
(simplify
(bit_and:c
(bit_and:c
(eq:c @0 @1)
(ne:c @1 @2)
)
(eq:c @0 @2)
)
( { falsevalue; } )
)
(simplify
(bit_and:c
(eq:c @0 @1)
(bit_and:c
(ne:c @1 @2)
(eq:c @0 @2)
)
)
( { falsevalue; } )
)
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug tree-optimization/110922] `(a == b) & (a == c) & (b != c)` is not optimized to false
2023-08-06 17:18 [Bug tree-optimization/110922] New: `(a == b) & (a == c) & (b != c)` is not optimized to false pinskia at gcc dot gnu.org
2023-08-06 17:21 ` [Bug tree-optimization/110922] " pinskia at gcc dot gnu.org
@ 2023-08-21 7:46 ` pinskia at gcc dot gnu.org
1 sibling, 0 replies; 3+ messages in thread
From: pinskia at gcc dot gnu.org @ 2023-08-21 7:46 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110922
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Assignee|unassigned at gcc dot gnu.org |pinskia at gcc dot gnu.org
Status|UNCONFIRMED |ASSIGNED
Last reconfirmed| |2023-08-21
Ever confirmed|0 |1
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Mine.
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2023-08-21 7:46 UTC | newest]
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2023-08-06 17:18 [Bug tree-optimization/110922] New: `(a == b) & (a == c) & (b != c)` is not optimized to false pinskia at gcc dot gnu.org
2023-08-06 17:21 ` [Bug tree-optimization/110922] " pinskia at gcc dot gnu.org
2023-08-21 7:46 ` pinskia at gcc dot gnu.org
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