[Bug middle-end/55271] New: missing warning set-but-unused

[Bug middle-end/55271] New: missing warning set-but-unused

[dimhen at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55271

             Bug #: 55271
           Summary: missing warning set-but-unused
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: dimhen@gmail.com


$ cat test.c 
void f()
{
// missing set-but-unused
    char *li = 0;
    *li = 0; // missing dereference-null ?
}
$ /usr/local/gcc_current_193387/bin/gcc -Wall -Wextra -Ofast test.c -c
$ /usr/local/gcc_current_193387/bin/gcc -v
Using built-in specs.
COLLECT_GCC=/usr/local/gcc_current_193387/bin/gcc
COLLECT_LTO_WRAPPER=/usr/local/gcc_current_193387/bin/../libexec/gcc/x86_64-unknown-linux-gnu/4.8.0/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: /home/dimhen/src/gcc-current/configure
--prefix=/usr/local/gcc_current --with-multilib-list=m64 --enable-__cxa_atexit
--enable-shared --enable-checking=yes,df,fold,rtl,tree
--enable-gnu-unique-object --enable-linker-build-id
--enable-languages=c,c++,lto --enable-plugin
--enable-version-specific-runtime-libs --with-tune=generic
Thread model: posix
gcc version 4.8.0 20121110 (experimental) [trunk revision 193387] (GCC)

[Bug middle-end/55271] missing warning set-but-unused

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55271

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-11-11 17:24:19 UTC ---
The pointer is used in *li = 0; statement.

[Bug middle-end/55271] missing warning set-but-unused

[dimhen at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55271

--- Comment #2 from Dmitry G. Dyachenko <dimhen at gmail dot com> 2012-11-11 18:42:25 UTC ---
oh, was over-simplified example. Sorry

void f1()
{
    char ch;
    char *p = &ch;
    *p = 0;
}

Now 2 variables are 'set-but-unused'?

[Bug middle-end/55271] missing warning set-but-unused

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55271

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
                 CC|                            |jakub at gcc dot gnu.org
         Resolution|                            |INVALID

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-11-11 20:24:39 UTC ---
No, they are both used.  ch in &ch, and p in *p.