* [Bug c/53131] -Wlogical-op: ready for prime time in -Wall ?
2012-04-26 20:18 [Bug c/53131] New: -Wlogical-op: ready for prime time in -Wall ? dcb314 at hotmail dot com
@ 2012-04-26 21:59 ` manu at gcc dot gnu.org
2012-04-28 7:30 ` dcb314 at hotmail dot com
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From: manu at gcc dot gnu.org @ 2012-04-26 21:59 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53131
Manuel López-Ibáñez <manu at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |diagnostic
CC| |manu at gcc dot gnu.org
Depends on| |43772
--- Comment #1 from Manuel López-Ibáñez <manu at gcc dot gnu.org> 2012-04-26 21:58:33 UTC ---
(In reply to comment #0)
> I am somewhat surprised that -Wlogical-op isn't part of either -Wall
> or possibly -Wextra.
It could be in -Wextra for GCC 4.8.
> I've just tried -Wlogical-op out on a build of a recent Linux kernel
> and 90 warnings are produced, so there is some evidence that
> it would be useful.
Do the warnings indicate bugs or not?
There is also PR43772, which would be nice to fix before enabling this in -Wall
or -Wextra. However, I don't even have any idea why we are warning there.
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug c/53131] -Wlogical-op: ready for prime time in -Wall ?
2012-04-26 20:18 [Bug c/53131] New: -Wlogical-op: ready for prime time in -Wall ? dcb314 at hotmail dot com
2012-04-26 21:59 ` [Bug c/53131] " manu at gcc dot gnu.org
@ 2012-04-28 7:30 ` dcb314 at hotmail dot com
2012-04-28 10:37 ` manu at gcc dot gnu.org
` (5 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: dcb314 at hotmail dot com @ 2012-04-28 7:30 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53131
--- Comment #2 from dcb <dcb314 at hotmail dot com> 2012-04-28 07:29:17 UTC ---
(In reply to comment #1)
> (In reply to comment #0)
> > I am somewhat surprised that -Wlogical-op isn't part of either -Wall
> > or possibly -Wextra.
>
> It could be in -Wextra for GCC 4.8.
Righto. If it works well there, it can be promoted to -Wall later.
> > I've just tried -Wlogical-op out on a build of a recent Linux kernel
> > and 90 warnings are produced, so there is some evidence that
> > it would be useful.
>
> Do the warnings indicate bugs or not?
Yes. I checked the first ten.
> There is also PR43772, which would be nice to fix before enabling this in -Wall
> or -Wextra. However, I don't even have any idea why we are warning there.
Agreed, although I wouldn't regard one broken corner case as a show stopper.
In general the warning does find bugs, even in heavily worked on code
like the Linux kernel. It finds nothing in the source code of gcc, however,
so no rework costs there.
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug c/53131] -Wlogical-op: ready for prime time in -Wall ?
2012-04-26 20:18 [Bug c/53131] New: -Wlogical-op: ready for prime time in -Wall ? dcb314 at hotmail dot com
2012-04-26 21:59 ` [Bug c/53131] " manu at gcc dot gnu.org
2012-04-28 7:30 ` dcb314 at hotmail dot com
@ 2012-04-28 10:37 ` manu at gcc dot gnu.org
2012-04-28 12:05 ` marc.glisse at normalesup dot org
` (4 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: manu at gcc dot gnu.org @ 2012-04-28 10:37 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53131
--- Comment #3 from Manuel López-Ibáñez <manu at gcc dot gnu.org> 2012-04-28 10:37:04 UTC ---
(In reply to comment #2)
> >
> > Do the warnings indicate bugs or not?
>
> Yes. I checked the first ten.
And what do the kernel people say? Do they want Wlogical-op enabled?
> > There is also PR43772, which would be nice to fix before enabling this in -Wall
> > or -Wextra. However, I don't even have any idea why we are warning there.
>
> Agreed, although I wouldn't regard one broken corner case as a show stopper.
>
Unfortunately, this corner case triggers in Emacs, so I guess it is not that
uncommon. My intention is to try to fix it before touching the status of
-Wlogical-op. This will make easier to convince GCC maintainers. However, I
have a long list of other things I would like to fix firstm and very little
free time, so if you (or anyone else) managed to find out why that bug
triggers, it would help already a lot.
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug c/53131] -Wlogical-op: ready for prime time in -Wall ?
2012-04-26 20:18 [Bug c/53131] New: -Wlogical-op: ready for prime time in -Wall ? dcb314 at hotmail dot com
` (2 preceding siblings ...)
2012-04-28 10:37 ` manu at gcc dot gnu.org
@ 2012-04-28 12:05 ` marc.glisse at normalesup dot org
2012-04-28 12:18 ` dcb314 at hotmail dot com
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From: marc.glisse at normalesup dot org @ 2012-04-28 12:05 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53131
Marc Glisse <marc.glisse at normalesup dot org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |marc.glisse at normalesup
| |dot org
--- Comment #4 from Marc Glisse <marc.glisse at normalesup dot org> 2012-04-28 12:05:20 UTC ---
(In reply to comment #2)
> > Do the warnings indicate bugs or not?
> Yes. I checked the first ten.
Could you give a sample? -Wlogical-op merges 2 unrelated warnings:
*) x && 2 (you would expect a boolean, not 2, so maybe x&2 was meant)
*) x<0 && x>0 (not so likely to happen) or x>=-5 || x<2 (always true)
and it is not clear which one you are most interested in.
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug c/53131] -Wlogical-op: ready for prime time in -Wall ?
2012-04-26 20:18 [Bug c/53131] New: -Wlogical-op: ready for prime time in -Wall ? dcb314 at hotmail dot com
` (3 preceding siblings ...)
2012-04-28 12:05 ` marc.glisse at normalesup dot org
@ 2012-04-28 12:18 ` dcb314 at hotmail dot com
2012-04-28 12:45 ` marc.glisse at normalesup dot org
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From: dcb314 at hotmail dot com @ 2012-04-28 12:18 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53131
--- Comment #5 from dcb <dcb314 at hotmail dot com> 2012-04-28 12:17:57 UTC ---
(In reply to comment #4)
> Could you give a sample? -Wlogical-op merges 2 unrelated warnings:
> *) x && 2 (you would expect a boolean, not 2, so maybe x&2 was meant)
> *) x<0 && x>0 (not so likely to happen) or x>=-5 || x<2 (always true)
>
> and it is not clear which one you are most interested in.
#2 is the one I am interested in.
I only discovered the other warning by accident, after 8
of the 10 warnings I checked closely.
I used the Linux kernel as an example. I'd probably need to analyse
more cases, in other packages too, to be sure that most of what
the warning finds is #2.
It seems a pretty small warning, but I guess #1 and #2 could
be split up, if that helps get #2 in.
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug c/53131] -Wlogical-op: ready for prime time in -Wall ?
2012-04-26 20:18 [Bug c/53131] New: -Wlogical-op: ready for prime time in -Wall ? dcb314 at hotmail dot com
` (4 preceding siblings ...)
2012-04-28 12:18 ` dcb314 at hotmail dot com
@ 2012-04-28 12:45 ` marc.glisse at normalesup dot org
2012-05-07 13:45 ` manu at gcc dot gnu.org
2015-04-23 9:49 ` mpolacek at gcc dot gnu.org
7 siblings, 0 replies; 9+ messages in thread
From: marc.glisse at normalesup dot org @ 2012-04-28 12:45 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53131
--- Comment #6 from Marc Glisse <marc.glisse at normalesup dot org> 2012-04-28 12:45:19 UTC ---
(In reply to comment #5)
> It seems a pretty small warning, but I guess #1 and #2 could
> be split up, if that helps get #2 in.
I think it is the opposite actually, #2 is more controversial than #1 (at least
until PR43772 is fixed).
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug c/53131] -Wlogical-op: ready for prime time in -Wall ?
2012-04-26 20:18 [Bug c/53131] New: -Wlogical-op: ready for prime time in -Wall ? dcb314 at hotmail dot com
` (5 preceding siblings ...)
2012-04-28 12:45 ` marc.glisse at normalesup dot org
@ 2012-05-07 13:45 ` manu at gcc dot gnu.org
2015-04-23 9:49 ` mpolacek at gcc dot gnu.org
7 siblings, 0 replies; 9+ messages in thread
From: manu at gcc dot gnu.org @ 2012-05-07 13:45 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53131
--- Comment #7 from Manuel López-Ibáñez <manu at gcc dot gnu.org> 2012-05-07 13:42:10 UTC ---
In fact, the main show-stopper for adding -Wlogical-op to -Wextra (or -Wall) is
PR40172, which was the reason it was moved out of -Wextra in the first place.
Someone would need to find a way to avoid warning in that case, for example
using the new tracking macro expansion infrastructure.
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug c/53131] -Wlogical-op: ready for prime time in -Wall ?
2012-04-26 20:18 [Bug c/53131] New: -Wlogical-op: ready for prime time in -Wall ? dcb314 at hotmail dot com
` (6 preceding siblings ...)
2012-05-07 13:45 ` manu at gcc dot gnu.org
@ 2015-04-23 9:49 ` mpolacek at gcc dot gnu.org
7 siblings, 0 replies; 9+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2015-04-23 9:49 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53131
Marek Polacek <mpolacek at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
CC| |mpolacek at gcc dot gnu.org
Resolution|--- |DUPLICATE
--- Comment #9 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
So I think we can close this as a dup; PR61534 has detailed info what needs to
be fixed.
*** This bug has been marked as a duplicate of bug 61534 ***
^ permalink raw reply [flat|nested] 9+ messages in thread