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* [Bug c++/96227] New: Comma operation sequencing issue
@ 2020-07-16 21:47 matt at godbolt dot org
2021-07-16 23:47 ` [Bug c++/96227] " pinskia at gcc dot gnu.org
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: matt at godbolt dot org @ 2020-07-16 21:47 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96227
Bug ID: 96227
Summary: Comma operation sequencing issue
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: matt at godbolt dot org
Target Milestone: ---
Filing on behalf of @lunasorcery (on twitter):
The following code:
```
#include <cstdio>
struct S {
S(char const* message) {
puts(message);
}
};
void operator,(S,S){}
int main() {
S("first"), S("second");
operator,(S("FIRST"), S("SECOND"));
}
```
Should produce the output:
first
second
FIRST
SECOND
But instead produces:
second
first
SECOND
FIRST
quotations from N4861:
[expr.comma]
"The left expression is sequenced before the right expression."
[over.match.oper]
"If either operand has a type that is a class or an enumeration,
a user-defined operator function might be declared that implements this
operator [...]
However, the operands are sequenced in the order prescribed for the built-in
operator."
[expr.call]
"If an operator function is invoked using operator notation, argument
evaluation is
sequenced as specified for the built-in operator; see 12.4.1.2."
https://gcc.godbolt.org/z/fdTG8q
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/96227] Comma operation sequencing issue
2020-07-16 21:47 [Bug c++/96227] New: Comma operation sequencing issue matt at godbolt dot org
@ 2021-07-16 23:47 ` pinskia at gcc dot gnu.org
2021-07-16 23:51 ` pinskia at gcc dot gnu.org
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-07-16 23:47 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96227
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Ever confirmed|0 |1
Last reconfirmed| |2021-07-16
Status|UNCONFIRMED |NEW
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed, Note this was partly fixed with the fix for PR 82959.
That is not invoked as a function case has been fixed for GCC 8.5.
On the trunk we produce as of today:
first
second
SECOND
FIRST
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/96227] Comma operation sequencing issue
2020-07-16 21:47 [Bug c++/96227] New: Comma operation sequencing issue matt at godbolt dot org
2021-07-16 23:47 ` [Bug c++/96227] " pinskia at gcc dot gnu.org
@ 2021-07-16 23:51 ` pinskia at gcc dot gnu.org
2021-07-17 7:36 ` jakub at gcc dot gnu.org
2022-12-19 21:43 ` pinskia at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-07-16 23:51 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96227
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |WAITING
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #1)
> Confirmed, Note this was partly fixed with the fix for PR 82959.
> That is not invoked as a function case has been fixed for GCC 8.5.
>
> On the trunk we produce as of today:
> first
> second
> SECOND
> FIRST
I actually think this is still correct output as the function call version is
not mentioned in "If an operator function is invoked using operator notation"
here.
Am I reading this correctly?
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/96227] Comma operation sequencing issue
2020-07-16 21:47 [Bug c++/96227] New: Comma operation sequencing issue matt at godbolt dot org
2021-07-16 23:47 ` [Bug c++/96227] " pinskia at gcc dot gnu.org
2021-07-16 23:51 ` pinskia at gcc dot gnu.org
@ 2021-07-17 7:36 ` jakub at gcc dot gnu.org
2022-12-19 21:43 ` pinskia at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: jakub at gcc dot gnu.org @ 2021-07-17 7:36 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96227
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |jakub at gcc dot gnu.org
--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
I think so, the evaluation order when invoking operator, not through the x, y
syntax is like for any other function call, the arguments evaluation is
indeterminately sequenced.
See https://en.cppreference.com/w/cpp/language/eval_order
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/96227] Comma operation sequencing issue
2020-07-16 21:47 [Bug c++/96227] New: Comma operation sequencing issue matt at godbolt dot org
` (2 preceding siblings ...)
2021-07-17 7:36 ` jakub at gcc dot gnu.org
@ 2022-12-19 21:43 ` pinskia at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu.org @ 2022-12-19 21:43 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96227
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|--- |8.5
Resolution|--- |FIXED
Status|WAITING |RESOLVED
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2022-12-19 21:43 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2020-07-16 21:47 [Bug c++/96227] New: Comma operation sequencing issue matt at godbolt dot org
2021-07-16 23:47 ` [Bug c++/96227] " pinskia at gcc dot gnu.org
2021-07-16 23:51 ` pinskia at gcc dot gnu.org
2021-07-17 7:36 ` jakub at gcc dot gnu.org
2022-12-19 21:43 ` pinskia at gcc dot gnu.org
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