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* [Bug c/45780] New: Warning for arithmetic operations involving C99 _Bool variable
@ 2010-09-24 18:40 ubizjak at gmail dot com
2010-09-24 19:06 ` [Bug c/45780] " ubizjak at gmail dot com
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: ubizjak at gmail dot com @ 2010-09-24 18:40 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45780
Summary: Warning for arithmetic operations involving C99 _Bool
variable
Product: gcc
Version: 4.5.2
Status: UNCONFIRMED
Severity: enhancement
Priority: P3
Component: c
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: ubizjak@gmail.com
Pasted from the thread that introduced _Bool in place of "GCC bool":
<quote>
> >> It can be done ultimately, but as a prerequisite, we should have
> >> warnings in -Wextra for all of
> >>
> >> ? boolvar++; ++boolvar;
> >> ? boolvar--; --boolvar;
> >> ? boolvar = nonbool;
> >> ? boolvar & nonbool; boolvar &= nonbool;
> >> ? boolvar | nonbool; boolvar |= nonbool;
> >> ? boolvar ^ nonbool; boolvar ^= nonbool;
> >
> > Fair enough. I have CCed Manuel, perhaps he is interested in this warning.
>
> I am not sure it fits in -Wconversion. -Wbool-arith perhaps?
It sounds like a warning for a -Wc90-c99-compat or similar option
(possibly in a more specific option such as -Wbool-arith) - pure C99 code
has little use for such a warning, it's about code that might be compiled
either with C99 _Bool, or with C90 unsigned char, and so needs to avoid
cases where they are incompatible. Such an option, similar in spirit to
-Wtraditional, could also allow you to get warnings in C99 mode for things
currently diagnosed with -std=c90 -pedantic.
</quote>
[1] http://gcc.gnu.org/ml/gcc-patches/2010-09/msg01941.html
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^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c/45780] Warning for arithmetic operations involving C99 _Bool variable
2010-09-24 18:40 [Bug c/45780] New: Warning for arithmetic operations involving C99 _Bool variable ubizjak at gmail dot com
@ 2010-09-24 19:06 ` ubizjak at gmail dot com
2010-11-03 20:05 ` ericb at gcc dot gnu.org
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: ubizjak at gmail dot com @ 2010-09-24 19:06 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45780
Uros Bizjak <ubizjak at gmail dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2010.09.24 18:44:45
date| |
Version|4.5.2 |unknown
Ever Confirmed|0 |1
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* [Bug c/45780] Warning for arithmetic operations involving C99 _Bool variable
2010-09-24 18:40 [Bug c/45780] New: Warning for arithmetic operations involving C99 _Bool variable ubizjak at gmail dot com
2010-09-24 19:06 ` [Bug c/45780] " ubizjak at gmail dot com
@ 2010-11-03 20:05 ` ericb at gcc dot gnu.org
2015-05-28 18:54 ` egall at gwmail dot gwu.edu
2015-05-29 2:29 ` egall at gwmail dot gwu.edu
3 siblings, 0 replies; 5+ messages in thread
From: ericb at gcc dot gnu.org @ 2010-11-03 20:05 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45780
Eric Blake <ericb at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |ericb at gcc dot gnu.org
--- Comment #1 from Eric Blake <ericb at gcc dot gnu.org> 2010-11-03 20:05:00 UTC ---
Don't forget a warning on implicit conversions from int to bool, such as:
bool f(int i) { return i; }
although it might make sense to avoid warnings on provably 0/1 int conversion
to bool, as in:
bool f(int i) { i = !!i; return i; }
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c/45780] Warning for arithmetic operations involving C99 _Bool variable
2010-09-24 18:40 [Bug c/45780] New: Warning for arithmetic operations involving C99 _Bool variable ubizjak at gmail dot com
2010-09-24 19:06 ` [Bug c/45780] " ubizjak at gmail dot com
2010-11-03 20:05 ` ericb at gcc dot gnu.org
@ 2015-05-28 18:54 ` egall at gwmail dot gwu.edu
2015-05-29 2:29 ` egall at gwmail dot gwu.edu
3 siblings, 0 replies; 5+ messages in thread
From: egall at gwmail dot gwu.edu @ 2015-05-28 18:54 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=45780
Eric Gallager <egall at gwmail dot gwu.edu> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |egall at gwmail dot gwu.edu
--- Comment #2 from Eric Gallager <egall at gwmail dot gwu.edu> ---
The -Wc90-c99-compat that made it into gcc5 currently warns about any usage of
bool whatsoever, not just the specific usages of bool listed in this bug...
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c/45780] Warning for arithmetic operations involving C99 _Bool variable
2010-09-24 18:40 [Bug c/45780] New: Warning for arithmetic operations involving C99 _Bool variable ubizjak at gmail dot com
` (2 preceding siblings ...)
2015-05-28 18:54 ` egall at gwmail dot gwu.edu
@ 2015-05-29 2:29 ` egall at gwmail dot gwu.edu
3 siblings, 0 replies; 5+ messages in thread
From: egall at gwmail dot gwu.edu @ 2015-05-29 2:29 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=45780
--- Comment #4 from Eric Gallager <egall at gwmail dot gwu.edu> ---
(In reply to Marek Polacek from comment #3)
> (In reply to Eric Gallager from comment #2)
> > The -Wc90-c99-compat that made it into gcc5 currently warns about
> > any usage of bool whatsoever, not just the specific usages of bool
> > listed in this bug...
>
> Right, that was the point of it.
...so is this bug worth keeping open then? It'd seem kinda redundant to me for
extra, more-specific warnings about bools to be placed in -Wc90-c99-compat (as
was originally proposed), when the flag already prints the more-generalized
warnings that it currently does. Or would they get their own separate
-Wbool-arith option? If so, what would happen when a user specifies both a
hypothetical -Wbool-arith flag along with -Wc90-c99-compat at the same time?
I'm just kinda worried that such a situation could lead to duplicated and/or
excessive warnings...
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2015-05-29 2:29 UTC | newest]
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2010-09-24 18:40 [Bug c/45780] New: Warning for arithmetic operations involving C99 _Bool variable ubizjak at gmail dot com
2010-09-24 19:06 ` [Bug c/45780] " ubizjak at gmail dot com
2010-11-03 20:05 ` ericb at gcc dot gnu.org
2015-05-28 18:54 ` egall at gwmail dot gwu.edu
2015-05-29 2:29 ` egall at gwmail dot gwu.edu
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