[Bug c++/61276] New: warn about possible coding errors with logical not (!)

[Bug c++/61276] New: warn about possible coding errors with logical not (!)

[manu at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61276

            Bug ID: 61276
           Summary: warn about possible coding errors with logical not (!)
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: manu at gcc dot gnu.org
                CC: dcb314 at hotmail dot com
        Depends on: 61271

+++ This bug was initially created as a clone of Bug #61271 +++

Clang detects this:

../../src/trunk/gcc/cgraphunit.c:1182:8: warning: logical not is only applied
to the left hand side of this comparison [-Wlogical-not-parentheses]

Source code is

      && (! TREE_CODE (target_node->decl) == FUNCTION_DECL

where 

      && (TREE_CODE (target_node->decl) != FUNCTION_DECL)

was intended.

GCC should have this warning which would have detected several obvious bugs in
GCC itself.

[Bug c++/61276] warn about possible coding errors with logical not (!)

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61276

--- Comment #2 from David Binderman <dcb314 at hotmail dot com> ---
(In reply to Manuel López-Ibáñez from comment #0)
> GCC should have this warning which would have detected several obvious bugs
> in GCC itself.

And at least 60 bugs in Fedora Linux, based on compiling
Fedora Linux with clang.

It would also find an unknown number of bugs in Linux kernel,
which compiles with gcc only, sadly.
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Subject: [Bug c++/61276] warn about possible coding errors with logical not (!)
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61276

--- Comment #3 from Manuel López-Ibáñez <manu at gcc dot gnu.org> ---
Just to mention that I cloned PR 61271 to not forget about implementing the
warning once the problematic code is fixed. So this PR should be about
implementing the warning, rather than fixing any particular problems.
>From gcc-bugs-return-452187-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org Wed May 21 16:25:16 2014
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Subject: [Bug c++/61276] warn about possible coding errors with logical not (!)
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61276

--- Comment #4 from Manuel López-Ibáñez <manu at gcc dot gnu.org> ---
(In reply to David Binderman from comment #2)
> It would also find an unknown number of bugs in Linux kernel,
> which compiles with gcc only, sadly.

Which I find sad is that GCC does not have such a simple warning after +20
years of development. 

Can't Google/RedHat/Oracle/Suse/Mentor/ARM/Linaro poll resources and have at
least one GCC developer committed to diagnostic issues? Just a single one
full-time developer will make such a huge difference.
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Subject: [Bug other/56955] documentation for attribute malloc contradicts itself
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https://gcc.gnu.org/bugzilla/show_bug.cgi?idV955

--- Comment #19 from rguenther at suse dot de <rguenther at suse dot de> ---
On May 21, 2014 5:14:27 PM CEST, eggert at gnu dot org
<gcc-bugzilla@gcc.gnu.org> wrote:
>https://gcc.gnu.org/bugzilla/show_bug.cgi?idV955
>
>--- Comment #18 from Paul Eggert <eggert at gnu dot org> ---
>(In reply to Richard Biener from comment #16)
>
>> void foo (int *p)
>> {
>>   int *q = realloc (p, sizeof (int));
>>   *q = 2;
>> }
>>
>> may I remove the store *q = 2 as dead?
>
>Yes, the consensus nowadays is that you can.
>
>I'll be happy to send the proposed change to gcc-patches but would like
>to be
>sure it's correct first.  Has this new information about realloc
>changed your
>opinion about whether realloc can be given the malloc attribute?

No, it has not.

Richard.

[Bug c++/61276] warn about possible coding errors with logical not (!)

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61276

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |diagnostic

--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Manuel López-Ibáñez from comment #3)
> Just to mention that I cloned PR 61271 to not forget about implementing the
> warning once the problematic code is fixed. So this PR should be about
> implementing the warning, rather than fixing any particular problems.

Oops, sorry I didn't read it properly!

(In reply to Manuel López-Ibáñez from comment #4)
> Can't Google/RedHat/Oracle/Suse/Mentor/ARM/Linaro poll resources and have at
> least one GCC developer committed to diagnostic issues? Just a single one
> full-time developer will make such a huge difference.

Although I agree with the sentiment it's just not practical, a full-time
developer can't really have seven different employers.
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Subject: [Bug c++/61133] g++ doesn't implement DR1760
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https://gcc.gnu.org/bugzilla/show_bug.cgi?ida133

--- Comment #2 from Jason Merrill <jason at gcc dot gnu.org> ---
Author: jason
Date: Wed May 21 17:23:07 2014
New Revision: 210720

URL: http://gcc.gnu.org/viewcvs?rev!0720&root=gcc&view=rev
Log:
    PR c++/61133
    * lambda.c (build_capture_proxy, add_capture): Treat normal
    captures and init-captures identically.

Added:
    trunk/gcc/testsuite/g++.dg/cpp1y/lambda-init8.C
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/lambda.c
    trunk/gcc/testsuite/g++.dg/cpp1y/lambda-init6.C

[Bug c++/61276] warn about possible coding errors with logical not (!)

[joseph at codesourcery dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61276

--- Comment #6 from joseph at codesourcery dot com <joseph at codesourcery dot com> ---
You could suggest GCC diagnostic issues to 
http://www.linuxfoundation.org/programs/core-infrastructure-initiative if 
you wish....

[Bug c++/61276] warn about possible coding errors with logical not (!)

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61276

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
                 CC|                            |mpolacek at gcc dot gnu.org
           Assignee|unassigned at gcc dot gnu.org      |mpolacek at gcc dot gnu.org
   Target Milestone|---                         |4.10.0

--- Comment #7 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
I have a (untested) patch for both C/C++ FEs.