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* [Bug c++/104388] New: Request: A builtin to mark an object as invalid
@ 2022-02-04 18:44 Darrell.Wright at gmail dot com
2022-02-04 22:14 ` [Bug c++/104388] " pinskia at gcc dot gnu.org
2022-02-07 7:45 ` rguenth at gcc dot gnu.org
0 siblings, 2 replies; 3+ messages in thread
From: Darrell.Wright at gmail dot com @ 2022-02-04 18:44 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104388
Bug ID: 104388
Summary: Request: A builtin to mark an object as invalid
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: Darrell.Wright at gmail dot com
Target Milestone: ---
Would it be possible to get a builtin that marks an object as invalid until it
is overwritten and make it IF if the object is used other than destruction,
assignment or taking its address/ref. I am naive on the compiler internals
here, but this could allow for the safety of destructive moves without the
changes to the object model around destruction ordering.
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug c++/104388] Request: A builtin to mark an object as invalid
2022-02-04 18:44 [Bug c++/104388] New: Request: A builtin to mark an object as invalid Darrell.Wright at gmail dot com
@ 2022-02-04 22:14 ` pinskia at gcc dot gnu.org
2022-02-07 7:45 ` rguenth at gcc dot gnu.org
1 sibling, 0 replies; 3+ messages in thread
From: pinskia at gcc dot gnu.org @ 2022-02-04 22:14 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104388
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Severity|normal |enhancement
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug c++/104388] Request: A builtin to mark an object as invalid
2022-02-04 18:44 [Bug c++/104388] New: Request: A builtin to mark an object as invalid Darrell.Wright at gmail dot com
2022-02-04 22:14 ` [Bug c++/104388] " pinskia at gcc dot gnu.org
@ 2022-02-07 7:45 ` rguenth at gcc dot gnu.org
1 sibling, 0 replies; 3+ messages in thread
From: rguenth at gcc dot gnu.org @ 2022-02-07 7:45 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104388
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Ever confirmed|0 |1
Status|UNCONFIRMED |WAITING
Last reconfirmed| |2022-02-07
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC internally places "clobbers" to mark object contents as invalid (as you
name it) and then can diagnose uses (but as "uninitialized") and can do
optimizations like remove dead stores into the now invalid object.
Those could be exposed as builtin.
Can you provide an example testcase how you'd use the builtin?
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2022-02-07 7:45 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2022-02-04 18:44 [Bug c++/104388] New: Request: A builtin to mark an object as invalid Darrell.Wright at gmail dot com
2022-02-04 22:14 ` [Bug c++/104388] " pinskia at gcc dot gnu.org
2022-02-07 7:45 ` rguenth at gcc dot gnu.org
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