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* [Bug lto/52399] New: With `-flto', `-Wno-clobbered' does not suppress the "might be clobbered" warning
@ 2012-02-27 10:12 d.g.gorbachev at gmail dot com
2012-02-27 11:19 ` [Bug lto/52399] " rguenth at gcc dot gnu.org
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: d.g.gorbachev at gmail dot com @ 2012-02-27 10:12 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52399
Bug #: 52399
Summary: With `-flto', `-Wno-clobbered' does not suppress the
"might be clobbered" warning
Classification: Unclassified
Product: gcc
Version: 4.7.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: lto
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: d.g.gorbachev@gmail.com
Created attachment 26761
--> http://gcc.gnu.org/bugzilla/attachment.cgi?id=26761
Invalid code
$ gcc -flto -O -Wall -Wno-clobbered pr52399.c
In file included from pr52399.c:3:0,
from :6:
pr52399.c: In function 'main':
pr52399.c:8:7: warning: variable 'i' might be clobbered by 'longjmp' or 'vfork'
[-Wclobbered]
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug lto/52399] With `-flto', `-Wno-clobbered' does not suppress the "might be clobbered" warning
2012-02-27 10:12 [Bug lto/52399] New: With `-flto', `-Wno-clobbered' does not suppress the "might be clobbered" warning d.g.gorbachev at gmail dot com
@ 2012-02-27 11:19 ` rguenth at gcc dot gnu.org
2012-02-27 14:09 ` manu at gcc dot gnu.org
2021-08-25 23:36 ` [Bug middle-end/52399] -Wclobbered should be a common option rather than a C family specific option pinskia at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: rguenth at gcc dot gnu.org @ 2012-02-27 11:19 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52399
Richard Guenther <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2012-02-27
Ever Confirmed|0 |1
--- Comment #1 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-02-27 11:16:47 UTC ---
Confirmed. This is because Wclobbered is a C family option but the warning
is generated by middle-end code. lto1 would simply ignore -Wno-clobbered.
-Wall is also a C family option and so ignored by lto1 btw. -Wall would need
to be split up in parts for lto option processing.
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug lto/52399] With `-flto', `-Wno-clobbered' does not suppress the "might be clobbered" warning
2012-02-27 10:12 [Bug lto/52399] New: With `-flto', `-Wno-clobbered' does not suppress the "might be clobbered" warning d.g.gorbachev at gmail dot com
2012-02-27 11:19 ` [Bug lto/52399] " rguenth at gcc dot gnu.org
@ 2012-02-27 14:09 ` manu at gcc dot gnu.org
2021-08-25 23:36 ` [Bug middle-end/52399] -Wclobbered should be a common option rather than a C family specific option pinskia at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: manu at gcc dot gnu.org @ 2012-02-27 14:09 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52399
Manuel López-Ibáñez <manu at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |manu at gcc dot gnu.org
--- Comment #2 from Manuel López-Ibáñez <manu at gcc dot gnu.org> 2012-02-27 14:03:06 UTC ---
(In reply to comment #1)
> Confirmed. This is because Wclobbered is a C family option but the warning
> is generated by middle-end code. lto1 would simply ignore -Wno-clobbered.
> -Wall is also a C family option and so ignored by lto1 btw. -Wall would need
> to be split up in parts for lto option processing.
In this testcase, -Wall is a red-herring, it doesn't affect -Wclobbered.
You get the same warning with:
$ gcc -flto -O pr52399.c
the reason is that -Wclobbered is initialized to -1, but only set to its
default value in c_common_post_options, which I guess lto1 does not call.
I guess the simplest fix is to make it a Common option and move the
initialization to finish_options. I am not sure whether it is possible to make
an option C/C++/LTO only.
In an ideal world, GCC options would have some kind of namespace, so one could
not use an option in the middle-end without specifying that it is handled by
LTO.
Ideally, GCC should also initialize options to their default value, instead of
using the -1 trick to check whether the option was set by the user. I am not
sure there is a mechanism yet to do this. This will have avoided this bug.
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug middle-end/52399] -Wclobbered should be a common option rather than a C family specific option
2012-02-27 10:12 [Bug lto/52399] New: With `-flto', `-Wno-clobbered' does not suppress the "might be clobbered" warning d.g.gorbachev at gmail dot com
2012-02-27 11:19 ` [Bug lto/52399] " rguenth at gcc dot gnu.org
2012-02-27 14:09 ` manu at gcc dot gnu.org
@ 2021-08-25 23:36 ` pinskia at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-08-25 23:36 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52399
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Component|lto |middle-end
Summary|With `-flto', |-Wclobbered should be a
|`-Wno-clobbered' does not |common option rather than a
|suppress the "might be |C family specific option
|clobbered" warning |
--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
So the warning does not happen any more with -flto but does -W does not enable
it either.
c-family/c.opt has:
Wclobbered
C ObjC C++ ObjC++ Var(warn_clobbered) Warning EnabledBy(Wextra)
Warn about variables that might be changed by \"longjmp\" or \"vfork\".
Maybe this should move to common.opt like the other middle-end warnings.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2021-08-25 23:36 UTC | newest]
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2012-02-27 10:12 [Bug lto/52399] New: With `-flto', `-Wno-clobbered' does not suppress the "might be clobbered" warning d.g.gorbachev at gmail dot com
2012-02-27 11:19 ` [Bug lto/52399] " rguenth at gcc dot gnu.org
2012-02-27 14:09 ` manu at gcc dot gnu.org
2021-08-25 23:36 ` [Bug middle-end/52399] -Wclobbered should be a common option rather than a C family specific option pinskia at gcc dot gnu.org
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