public inbox for gcc-prs@sourceware.org
help / color / mirror / Atom feed
* Re: c/9072: -Wconversion should be split into two distinct flags
@ 2003-02-03 0:16 Joseph S. Myers
0 siblings, 0 replies; 11+ messages in thread
From: Joseph S. Myers @ 2003-02-03 0:16 UTC (permalink / raw)
To: nobody; +Cc: gcc-prs
The following reply was made to PR c/9072; it has been noted by GNATS.
From: "Joseph S. Myers" <jsm28@cam.ac.uk>
To: <bangerth@dealii.org>, <128950@bugs.debian.org>, <agthorr@barsoom.org>,
<gcc-bugs@gcc.gnu.org>, <segher@koffie.nl>, <gcc-gnats@gcc.gnu.org>
Cc:
Subject: Re: c/9072: -Wconversion should be split into two distinct flags
Date: Mon, 3 Feb 2003 00:08:30 +0000 (GMT)
On 2 Feb 2003 bangerth@dealii.org wrote:
> Has been analyzed. Patch is even in the audit trail, but
> seems to have become stuck in gcc's patch acceptance machinery...
The patch isn't even one suitable for review, as it lacks testcases. It
is established procedure [0] that patches failing to follow the standards
adequately get ignored. Even with them, it just papers over particular
problems rather than actually implementing a sensible consistent
specification for -Wconversion.
[0] This is very bad procedure; ignoring patches rather than explaining
what is wrong is far too likely to lose potential contributors. It is,
however, what happens; patches not following the standards are more
tedious to review than ones following the standards, and even many good
patches following the standards get ignored. However, this patch was not
ignored; it received several comments on what ought to be done.
I expect a patch that followed the GNU and GCC coding standards, including
thorough testcases, and implemented the simple specification I gave for
-Wconversion (warn for any implicit conversion that may change a value),
would get reviewed.
--
Joseph S. Myers
jsm28@cam.ac.uk
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: c/9072: -Wconversion should be split into two distinct flags
@ 2003-02-03 16:36 Wolfgang Bangerth
0 siblings, 0 replies; 11+ messages in thread
From: Wolfgang Bangerth @ 2003-02-03 16:36 UTC (permalink / raw)
To: nobody; +Cc: gcc-prs
The following reply was made to PR c/9072; it has been noted by GNATS.
From: Wolfgang Bangerth <bangerth@ticam.utexas.edu>
To: "Joseph S. Myers" <jsm28@cam.ac.uk>
Cc: 128950@bugs.debian.org, <agthorr@barsoom.org>, <gcc-bugs@gcc.gnu.org>,
<segher@koffie.nl>, <gcc-gnats@gcc.gnu.org>
Subject: Re: c/9072: -Wconversion should be split into two distinct flags
Date: Mon, 3 Feb 2003 10:31:41 -0600 (CST)
On Mon, 3 Feb 2003, Joseph S. Myers wrote:
> > Has been analyzed. Patch is even in the audit trail, but
> > seems to have become stuck in gcc's patch acceptance machinery...
>
> The patch isn't even one suitable for review, as it lacks testcases. It
> is established procedure [0] that patches failing to follow the standards
> adequately get ignored.
Sorry, don't flame me :-) I am just trying to find ways to get patch
submitters and potential reviewers together.
The bug database is full with reports that have patches attached. If
nobody with the ability to judge things takes a look at them, then they
will remain open forever. I'm just trying to spark discussion on them.
Every once in a while I succeed to get a patch into CVS this way. I think
that's better than just letting them sleep.
> [0] This is very bad procedure; ignoring patches rather than explaining
> what is wrong is far too likely to lose potential contributors.
Exactly. If there's someone with little knowledge of gcc processes who
manages to find a patch that then never gets any attention, he's not
likely to try again next time. If he does get feedback, and be it only
that the patch is basically that it is ok but a Changelog entry missing
and that the ChangeLog format is described at XYZ, then that'll motivate
people.
I do understand why this is so, but we're doing badly in this field!
Regards
Wolfgang
PS: Segher - I think the idea of this PR is right, and I would certainly
appreciate if you could submit a patch! Thanks!
-------------------------------------------------------------------------
Wolfgang Bangerth email: bangerth@ticam.utexas.edu
www: http://www.ticam.utexas.edu/~bangerth/
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: c/9072: -Wconversion should be split into two distinct flags
@ 2003-02-03 2:36 Agthorr
0 siblings, 0 replies; 11+ messages in thread
From: Agthorr @ 2003-02-03 2:36 UTC (permalink / raw)
To: nobody; +Cc: gcc-prs
The following reply was made to PR c/9072; it has been noted by GNATS.
From: Agthorr <agthorr@barsoom.org>
To: Segher Boessenkool <segher@koffie.nl>
Cc: "Joseph S. Myers" <jsm28@cam.ac.uk>, bangerth@dealii.org,
128950@bugs.debian.org, gcc-bugs@gcc.gnu.org, gcc-gnats@gcc.gnu.org
Subject: Re: c/9072: -Wconversion should be split into two distinct flags
Date: Sun, 2 Feb 2003 18:34:44 -0800
On Mon, Feb 03, 2003 at 02:57:26AM +0100, Segher Boessenkool wrote:
> I didn't intend for it to be reviewed; I just asked if this was
> the kind of thing that was asked for. Writing a good patch for
> this was far more work (esp. writing a testcase that covers
> all cases). I have one in the works but as there was not
> much interest I dropped it on the floor. If anyone still wants
> it, better speak up.
Hello,
I'm the person who originally filed this bug. Your patch does indeed
seem to do what I want, and I would love to see it (or something
similar) in a future version of gcc. I agree that passing a parameter
to a function should be considered an assignment for -Wconversion
purposes. I also agree with Joseph Myers' statement that -Wconversion
should "warn for any implicit conversion that may change a value".
> True. But no consensus was reached on whether this was a good idea
> at all. As this is mostly tedious, non-fun work and I don't get
> paid a dime to do it, and no-one cheered me on, it wasn't a priority
> work for me (and I forgot about it, really).
CHEER! CHEER!
I apologize for not responding sooner. I'm a graduate student and
have been ill on-and-off since mid-December. This does not make for
free time for responding to email :)
I realize that this is not a high-priority issue, but I do appreciate
any effort that goes into making -Wconversion more useful.
-- Agthorr
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: c/9072: -Wconversion should be split into two distinct flags
@ 2003-02-03 2:06 Segher Boessenkool
0 siblings, 0 replies; 11+ messages in thread
From: Segher Boessenkool @ 2003-02-03 2:06 UTC (permalink / raw)
To: nobody; +Cc: gcc-prs
The following reply was made to PR c/9072; it has been noted by GNATS.
From: Segher Boessenkool <segher@koffie.nl>
To: "Joseph S. Myers" <jsm28@cam.ac.uk>
Cc: bangerth@dealii.org, 128950@bugs.debian.org, agthorr@barsoom.org,
gcc-bugs@gcc.gnu.org, gcc-gnats@gcc.gnu.org
Subject: Re: c/9072: -Wconversion should be split into two distinct flags
Date: Mon, 03 Feb 2003 02:57:26 +0100
Joseph S. Myers wrote:
> On 2 Feb 2003 bangerth@dealii.org wrote:
>
>
>> Has been analyzed. Patch is even in the audit trail, but
>> seems to have become stuck in gcc's patch acceptance machinery...
>
>
> The patch isn't even one suitable for review, as it lacks testcases. It
I didn't intend for it to be reviewed; I just asked if this was
the kind of thing that was asked for. Writing a good patch for
this was far more work (esp. writing a testcase that covers
all cases). I have one in the works but as there was not
much interest I dropped it on the floor. If anyone still wants
it, better speak up.
> [0] This is very bad procedure; ignoring patches rather than explaining
> what is wrong is far too likely to lose potential contributors. It is,
Agreed.
> however, what happens; patches not following the standards are more
> tedious to review than ones following the standards, and even many good
> patches following the standards get ignored. However, this patch was not
> ignored; it received several comments on what ought to be done.
True. But no consensus was reached on whether this was a good idea
at all. As this is mostly tedious, non-fun work and I don't get
paid a dime to do it, and no-one cheered me on, it wasn't a priority
work for me (and I forgot about it, really).
> I expect a patch that followed the GNU and GCC coding standards, including
> thorough testcases, and implemented the simple specification I gave for
> -Wconversion (warn for any implicit conversion that may change a value),
> would get reviewed.
I'd like to hear whether this change to the semantics of -Wconversion
is likely to be accepted, first.
Cheers,
Segher
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: c/9072: -Wconversion should be split into two distinct flags
@ 2003-02-02 22:54 bangerth
0 siblings, 0 replies; 11+ messages in thread
From: bangerth @ 2003-02-02 22:54 UTC (permalink / raw)
To: 128950, agthorr, gcc-bugs, gcc-prs, nobody, segher
Synopsis: -Wconversion should be split into two distinct flags
State-Changed-From-To: open->analyzed
State-Changed-By: bangerth
State-Changed-When: Sun Feb 2 22:54:20 2003
State-Changed-Why:
Has been analyzed. Patch is even in the audit trail, but
seems to have become stuck in gcc's patch acceptance machinery...
W.
http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=9072
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: c/9072: -Wconversion should be split into two distinct flags
@ 2002-12-29 4:06 Joseph S. Myers
0 siblings, 0 replies; 11+ messages in thread
From: Joseph S. Myers @ 2002-12-29 4:06 UTC (permalink / raw)
To: nobody; +Cc: gcc-prs
The following reply was made to PR c/9072; it has been noted by GNATS.
From: "Joseph S. Myers" <jsm28@cam.ac.uk>
To: Zack Weinberg <zack@codesourcery.com>
Cc: Segher Boessenkool <segher@koffie.nl>, <128950@bugs.debian.org>,
<gcc-patches@gcc.gnu.org>, <gcc-gnats@gcc.gnu.org>,
<debian-gcc@lists.debian.org>
Subject: Re: c/9072: -Wconversion should be split into two distinct flags
Date: Sun, 29 Dec 2002 11:59:26 +0000 (GMT)
On Sun, 29 Dec 2002, Zack Weinberg wrote:
> I'm very much in favor of making -Wconversion more useful, but is
> there any reason not to shift the argument-type-conversion warnings
> entirely over to -Wtraditional? Particularly if the warning is
> avoided for prototypes in system headers (so that 'sinf' and the like
> raise no complaints) -- this would, for instance, catch the occasional
> problem we have with arguments of type 'bool' in GCC itself.
>
> Then -Wconversion would be entirely for dubious type conversions on
> assignment.
I believe -Wconversion should have exactly the following simple
specification: warn for any implicit conversion that may change a value.
This implies -Wsign-compare, parts of the existing -Wconversion (but not
those for widening through prototype, etc.), and various cases that there
isn't currently a warning option for (e.g. assigning a signed int to an
unsigned int), and would be useful for security auditing. The same
intelligence used by -Wsign-compare to avoid warning where problems cannot
in fact arise (e.g. comparing a constant positive signed integer to an
unsigned integer) should be used. Depending on how many warnings this
generates for reasonable code, there may need to be options to disable
individual parts (beyond the existing -Wno-sign-compare).
Some parts of this might also be useful in -Wtraditional.
Such a -Wconversion implementation would need thorough testcases (probably
a few hundred lines, likely rather longer than the rest of the patch) for
all the different cases of implicit conversion that do warn, or don't warn
because that type conversion can't change values, or don't warn because
that conversion is converting a constant (etc.) to the same value.
--
Joseph S. Myers
jsm28@cam.ac.uk
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: c/9072: -Wconversion should be split into two distinct flags
@ 2002-12-29 1:06 Zack Weinberg
0 siblings, 0 replies; 11+ messages in thread
From: Zack Weinberg @ 2002-12-29 1:06 UTC (permalink / raw)
To: nobody; +Cc: gcc-prs
The following reply was made to PR c/9072; it has been noted by GNATS.
From: Zack Weinberg <zack@codesourcery.com>
To: Segher Boessenkool <segher@koffie.nl>
Cc: 128950@bugs.debian.org, gcc-patches@gcc.gnu.org,
gcc-gnats@gcc.gnu.org,
debian-gcc@lists.debian.org
Subject: Re: c/9072: -Wconversion should be split into two distinct flags
Date: Sun, 29 Dec 2002 01:05:43 -0800
Segher Boessenkool <segher@koffie.nl> writes:
> Zack Weinberg wrote:
>>
>> I'm very much in favor of making -Wconversion more useful, but is
>> there any reason not to shift the argument-type-conversion warnings
>> entirely over to -Wtraditional? Particularly if the warning is
>> avoided for prototypes in system headers (so that 'sinf' and the like
>> raise no complaints) -- this would, for instance, catch the occasional
>> problem we have with arguments of type 'bool' in GCC itself.
>>
>> Then -Wconversion would be entirely for dubious type conversions on
>> assignment.
>
> This is the intended behaviour of my patch, modulo in my opinion passing
> a "too wide" argument to a function is a dubious assignment, too.
I may have misunderstood the effect of your patch - it seemed like you
would need to give both -Wconversion and -Wtraditional to get the
argument-type conversion warnings. I was suggesting that this should
happen with just -Wtraditional.
zw
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: c/9072: -Wconversion should be split into two distinct flags
@ 2002-12-29 0:56 Segher Boessenkool
0 siblings, 0 replies; 11+ messages in thread
From: Segher Boessenkool @ 2002-12-29 0:56 UTC (permalink / raw)
To: nobody; +Cc: gcc-prs
The following reply was made to PR c/9072; it has been noted by GNATS.
From: Segher Boessenkool <segher@koffie.nl>
To: Zack Weinberg <zack@codesourcery.com>
Cc: 128950@bugs.debian.org, gcc-patches@gcc.gnu.org,
gcc-gnats@gcc.gnu.org, debian-gcc@lists.debian.org
Subject: Re: c/9072: -Wconversion should be split into two distinct flags
Date: Sun, 29 Dec 2002 09:48:17 +0100
Zack Weinberg wrote:
>
> I'm very much in favor of making -Wconversion more useful, but is
> there any reason not to shift the argument-type-conversion warnings
> entirely over to -Wtraditional? Particularly if the warning is
> avoided for prototypes in system headers (so that 'sinf' and the like
> raise no complaints) -- this would, for instance, catch the occasional
> problem we have with arguments of type 'bool' in GCC itself.
>
> Then -Wconversion would be entirely for dubious type conversions on
> assignment.
This is the intended behaviour of my patch, modulo in my opinion passing
a "too wide" argument to a function is a dubious assignment, too.
Segher
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: c/9072: -Wconversion should be split into two distinct flags
@ 2002-12-29 0:46 Zack Weinberg
0 siblings, 0 replies; 11+ messages in thread
From: Zack Weinberg @ 2002-12-29 0:46 UTC (permalink / raw)
To: nobody; +Cc: gcc-prs
The following reply was made to PR c/9072; it has been noted by GNATS.
From: Zack Weinberg <zack@codesourcery.com>
To: Segher Boessenkool <segher@koffie.nl>
Cc: 128950@bugs.debian.org, gcc-patches@gcc.gnu.org,
gcc-gnats@gcc.gnu.org,
debian-gcc@lists.debian.org
Subject: Re: c/9072: -Wconversion should be split into two distinct flags
Date: Sun, 29 Dec 2002 00:37:58 -0800
Segher Boessenkool <segher@koffie.nl> writes:
> Matthias Klose wrote:
>> It'd be nice if these two behaviors were two controlled via two
>> separate flags. The second behavior would have caught a bug I've been
>> hunting for hours, while the first behavior is very undesirable to me
>> (and useless since I also compile with -Wstrict-prototypes).
>
> I remember having been annoyed by -Wconversion its behaviour, too. Maybe
> this patch will do what you want?
I'm very much in favor of making -Wconversion more useful, but is
there any reason not to shift the argument-type-conversion warnings
entirely over to -Wtraditional? Particularly if the warning is
avoided for prototypes in system headers (so that 'sinf' and the like
raise no complaints) -- this would, for instance, catch the occasional
problem we have with arguments of type 'bool' in GCC itself.
Then -Wconversion would be entirely for dubious type conversions on
assignment.
zw
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: c/9072: -Wconversion should be split into two distinct flags
@ 2002-12-28 22:16 Segher Boessenkool
0 siblings, 0 replies; 11+ messages in thread
From: Segher Boessenkool @ 2002-12-28 22:16 UTC (permalink / raw)
To: nobody; +Cc: gcc-prs
The following reply was made to PR c/9072; it has been noted by GNATS.
From: Segher Boessenkool <segher@koffie.nl>
To: 128950@bugs.debian.org, gcc-patches@gcc.gnu.org
Cc: gcc-gnats@gcc.gnu.org, debian-gcc@lists.debian.org
Subject: Re: c/9072: -Wconversion should be split into two distinct flags
Date: Sat, 28 Dec 2002 17:56:27 +0100
Matthias Klose wrote:
>
> The -Wconversion option to gcc is documented as doing two things:
>
> ------------------------------------------------------------------------
> `-Wconversion'
> Warn if a prototype causes a type conversion that is different
> from what would happen to the same argument in the absence of a
> prototype. This includes conversions of fixed point to floating
> and vice versa, and conversions changing the width or signedness
> of a fixed point argument except when the same as the default
> promotion.
>
> Also, warn if a negative integer constant expression is implicitly
> converted to an unsigned type. For example, warn about the
> assignment `x = -1' if `x' is unsigned. But do not warn about
> explicit casts like `(unsigned) -1'.
> ------------------------------------------------------------------------
>
> It'd be nice if these two behaviors were two controlled via two
> separate flags. The second behavior would have caught a bug I've been
> hunting for hours, while the first behavior is very undesirable to me
> (and useless since I also compile with -Wstrict-prototypes).
I remember having been annoyed by -Wconversion its behaviour, too. Maybe
this patch will do what you want?
Segher
2002-12-28 Segher Boessenkool <segher@koffie.nl>
* c-typeck.c (convert_arguments): Don't warn about arguments
passed as `float' unless -Wtraditional given. Add warning
to -Wconversion for passing floating point arguments in smaller
precision. Add warning to -Wtraditional for passing integers with
different width due to prototype.
* doc/invoke.texi (Warning Options): Document this. Clarify.
* doc/trouble.texi (Protoize Caveats): Ditto.
*** ../../gcc-clean/gcc/c-typeck.c Fri Dec 27 03:21:39 2002
--- ./c-typeck.c Sat Dec 28 16:44:19 2002
*************** convert_arguments (typelist, values, nam
*** 1645,1657 ****
{
/* Warn if any argument is passed as `float',
since without a prototype it would be `double'. */
! if (formal_prec == TYPE_PRECISION (float_type_node))
warn_for_assignment ("%s as `float' rather than `double' due to prototype", (char *) 0, name, parmnum + 1);
}
/* Detect integer changing in width or signedness.
! These warnings are only activated with
-Wconversion, not with -Wtraditional. */
! else if (warn_conversion && INTEGRAL_TYPE_P (type)
&& INTEGRAL_TYPE_P (TREE_TYPE (val)))
{
tree would_have_been = default_conversion (val);
--- 1645,1659 ----
{
/* Warn if any argument is passed as `float',
since without a prototype it would be `double'. */
! if (warn_traditional && formal_prec == TYPE_PRECISION (float_type_node))
warn_for_assignment ("%s as `float' rather than `double' due to prototype", (char *) 0, name, parmnum + 1);
+ else if (warn_conversion && TYPE_PRECISION (TREE_TYPE (val)) < formal_prec)
+ warn_for_assignment ("%s with smaller precision due to prototype", (char *) 0, name, parmnum + 1);
}
/* Detect integer changing in width or signedness.
! The warning for signedness is only activated with
-Wconversion, not with -Wtraditional. */
! else if (INTEGRAL_TYPE_P (type)
&& INTEGRAL_TYPE_P (TREE_TYPE (val)))
{
tree would_have_been = default_conversion (val);
*************** convert_arguments (typelist, values, nam
*** 1666,1671 ****
--- 1668,1675 ----
else if (formal_prec != TYPE_PRECISION (type1))
warn_for_assignment ("%s with different width due to prototype", (char *) 0, name, parmnum + 1);
else if (TREE_UNSIGNED (type) == TREE_UNSIGNED (type1))
+ ;
+ else if (!warn_conversion)
;
/* Don't complain if the formal parameter type
is an enum, because we can't tell now whether
*** ../../gcc-clean/gcc/doc/invoke.texi Fri Dec 27 03:21:40 2002
--- ./doc/invoke.texi Sat Dec 28 16:27:54 2002
*************** traditional C case.
*** 2600,2610 ****
@item
Conversions by prototypes between fixed/floating point values and vice
! versa. The absence of these prototypes when compiling with traditional
C would cause serious problems. This is a subset of the possible
conversion warnings, for the full set use @option{-Wconversion}.
@item
Use of ISO C style function definitions. This warning intentionally is
@emph{not} issued for prototype declarations or variadic functions
because these ISO C features will appear in your code when using
--- 2600,2616 ----
@item
Conversions by prototypes between fixed/floating point values and vice
! versa, and conversion by prototypes between different width types when
! not equal to the default promotions.
! The absence of these prototypes when compiling with traditional
C would cause serious problems. This is a subset of the possible
conversion warnings, for the full set use @option{-Wconversion}.
@item
+ Use of @code{float} in prototypes. Traditional C would pass such
+ parameters as @code{double}, while ISO C does not.
+
+ @item
Use of ISO C style function definitions. This warning intentionally is
@emph{not} issued for prototype declarations or variadic functions
because these ISO C features will appear in your code when using
*************** this is why we did not make @option{-Wal
*** 2671,2681 ****
@item -Wconversion
@opindex Wconversion
! Warn if a prototype causes a type conversion that is different from what
! would happen to the same argument in the absence of a prototype. This
! includes conversions of fixed point to floating and vice versa, and
! conversions changing the width or signedness of a fixed point argument
! except when the same as the default promotion.
Also, warn if a negative integer constant expression is implicitly
converted to an unsigned type. For example, warn about the assignment
--- 2677,2687 ----
@item -Wconversion
@opindex Wconversion
! Warn if a prototype causes an implicit type conversion that is different
! from the default promotion. This includes conversions of fixed point to
! floating and vice versa, and conversions changing the width or
! signedness of a fixed point argument (except when the same as the default
! promotion).
Also, warn if a negative integer constant expression is implicitly
converted to an unsigned type. For example, warn about the assignment
*** ../../gcc-clean/gcc/doc/trouble.texi Mon Sep 16 00:48:05 2002
--- ./doc/trouble.texi Sat Dec 28 16:29:53 2002
*************** without them.
*** 1110,1117 ****
@opindex Wconversion
You can find all the places where this problem might occur by compiling
! the program with the @option{-Wconversion} option. It prints a warning
! whenever an argument is converted.
@item
Both conversion programs can be confused if there are macro calls in and
--- 1110,1117 ----
@opindex Wconversion
You can find all the places where this problem might occur by compiling
! the program with the @option{-Wtraditional -Wconversion} options. It
! prints a warning whenever an argument is converted.
@item
Both conversion programs can be confused if there are macro calls in and
^ permalink raw reply [flat|nested] 11+ messages in thread
* c/9072: -Wconversion should be split into two distinct flags
@ 2002-12-27 15:36 Matthias Klose
0 siblings, 0 replies; 11+ messages in thread
From: Matthias Klose @ 2002-12-27 15:36 UTC (permalink / raw)
To: gcc-gnats, debian-gcc
>Number: 9072
>Category: c
>Synopsis: -Wconversion should be split into two distinct flags
>Confidential: no
>Severity: non-critical
>Priority: low
>Responsible: unassigned
>State: open
>Class: change-request
>Submitter-Id: net
>Arrival-Date: Fri Dec 27 15:36:02 PST 2002
>Closed-Date:
>Last-Modified:
>Originator: Agthorr <agthorr@barsoom.org>
>Release: 3.2.1 (Debian) (Debian unstable)
>Organization:
The Debian Project
>Environment:
System: Debian GNU/Linux (unstable)
Architecture: i686
host: i386-linux
Configured with: ../src/configure -v --enable-languages=c,c++,java,f77,proto,pascal,objc,ada --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --with-gxx-include-dir=/usr/include/c++/3.2 --enable-shared --with-system-zlib --enable-nls --without-included-gettext --enable-__cxa_atexit --enable-clocale=gnu --enable-java-gc=boehm --enable-objc-gc i386-linux
Thread model: posix
gcc version 3.2.2 20021212 (Debian prerelease)
>Description:
[ Reported to the Debian BTS as report #128950.
Please CC 128950@bugs.debian.org on replies.
Log of report can be found at http://bugs.debian.org/128950 ]
The -Wconversion option to gcc is documented as doing two things:
------------------------------------------------------------------------
`-Wconversion'
Warn if a prototype causes a type conversion that is different
from what would happen to the same argument in the absence of a
prototype. This includes conversions of fixed point to floating
and vice versa, and conversions changing the width or signedness
of a fixed point argument except when the same as the default
promotion.
Also, warn if a negative integer constant expression is implicitly
converted to an unsigned type. For example, warn about the
assignment `x = -1' if `x' is unsigned. But do not warn about
explicit casts like `(unsigned) -1'.
------------------------------------------------------------------------
It'd be nice if these two behaviors were two controlled via two
separate flags. The second behavior would have caught a bug I've been
hunting for hours, while the first behavior is very undesirable to me
(and useless since I also compile with -Wstrict-prototypes).
>How-To-Repeat:
>Fix:
>Release-Note:
>Audit-Trail:
>Unformatted:
^ permalink raw reply [flat|nested] 11+ messages in thread
end of thread, other threads:[~2003-02-03 16:36 UTC | newest]
Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2003-02-03 0:16 c/9072: -Wconversion should be split into two distinct flags Joseph S. Myers
-- strict thread matches above, loose matches on Subject: below --
2003-02-03 16:36 Wolfgang Bangerth
2003-02-03 2:36 Agthorr
2003-02-03 2:06 Segher Boessenkool
2003-02-02 22:54 bangerth
2002-12-29 4:06 Joseph S. Myers
2002-12-29 1:06 Zack Weinberg
2002-12-29 0:56 Segher Boessenkool
2002-12-29 0:46 Zack Weinberg
2002-12-28 22:16 Segher Boessenkool
2002-12-27 15:36 Matthias Klose
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).