Michal, why are you comiling with -fno-strict-aliasing? Any problems
with C aliasing should IMO be reported as bugs and fixed quickly,
because it causes trouble with other platforms and portabilty.

The warnings in your mail, which gcc and ast-open version did you use?
I tested with Suse 12.1, gcc (SUSE Linux) 4.6.2, ast-open.2012-02-14
and only got this one warning
src/lib/libast/vmalloc/vmstat.c: In function 'vmstat':
src/lib/libast/vmalloc/vmstat.c:100:7: warning: dereferencing
type-punned pointer will break strict-aliasing rules
[-Wstrict-aliasing]

Olga

On Tue, Feb 28, 2012 at 3:59 PM, Michal Hlavinka <[email protected]> wrote:
> On 02/26/2012 01:29 PM, ольга крыжановская wrote:
>>
>> Glenn, I use a newer gcc version: gcc (SUSE Linux) 4.5.0 20100604
>> [gcc-4_5-branch revision 160292].
>>
>> Can any one in the list confirm the warning with gcc>= 4.5?
>
>
> We use -fno-strict-aliasing for ksh compilation. I've turned it off and got
> this:
>
> src/lib/libast/vmalloc/vmbest.c:202:5: warning: dereferencing type-punned
> pointer will break strict-aliasing rules
> src/lib/libast/vmalloc/vmbest.c:440:4: warning: dereferencing type-punned
> pointer will break strict-aliasing rules
> src/lib/libast/vmalloc/vmbest.c:571:3: warning: dereferencing type-punned
> pointer will break strict-aliasing rules
> src/lib/libast/vmalloc/vmbest.c:682:3: warning: dereferencing type-punned
> pointer will break strict-aliasing rules
> src/lib/libast/vmalloc/vmbest.c:693:5: warning: dereferencing type-punned
> pointer will break strict-aliasing rules
> src/lib/libast/vmalloc/vmbest.c:694:5: warning: dereferencing type-punned
> pointer will break strict-aliasing rules
> src/lib/libast/vmalloc/vmopen.c:145:2: warning: dereferencing type-punned
> pointer will break strict-aliasing rules
> src/lib/libast/vmalloc/vmopen.c:150:2: warning: dereferencing type-punned
> pointer will break strict-aliasing rules
> src/lib/libast/vmalloc/vmopen.c:151:2: warning: dereferencing type-punned
> pointer will break strict-aliasing rules
> src/lib/libast/vmalloc/vmprivate.c:169:2: warning: dereferencing type-punned
> pointer will break strict-aliasing rules
>
> src/lib/libast/vmalloc/vmstat.c:100:7: warning: dereferencing type-punned
> pointer will break strict-aliasing rules
> src/lib/libast/vmalloc/vmstat.c:102:7: warning: dereferencing type-punned
> pointer will break strict-aliasing rules
> src/lib/libsum/sum-sha2.c:743:2: warning: dereferencing type-punned pointer
> will break strict-aliasing rules
> src/lib/libsum/sum-sha2.c:1104:2: warning: dereferencing type-punned pointer
> will break strict-aliasing rules
> src/lib/libsum/sum-sha2.c:1105:2: warning: dereferencing type-punned pointer
> will break strict-aliasing rules
> src/cmd/ksh93/edit/emacs.c:1077:7: warning: dereferencing type-punned
> pointer will break strict-aliasing rules
> src/cmd/ksh93/edit/emacs.c:1079:7: warning: dereferencing type-punned
> pointer will break strict-aliasing rules
>
>
>>
>> Olga
>>
>> On Sun, Feb 26, 2012 at 7:02 AM, Glenn Fowler<[email protected]>
>>  wrote:
>>>
>>>
>>> I don;t see this with
>>> gcc version 4.3.4 [gcc-4_3-branch revision 152973] (SUSE Linux)
>>>
>>> On Wed, 15 Feb 2012 23:32:38 +0100 =?KOI8-R?B?z8zYx8Egy9LZ1sHOz9fTy8HR?=
>>> wrote:
>>>>
>>>> Glenn, in libast's vmalloc I get this warning if I compile libast on
>>>> Suse Linux with gcc4 and CCFLAGS='-O3 -flto -fstrict-aliasing
>>>> -Wstrict-aliasing': src/lib/libast/vmalloc/vmstat.c:100:7: warning:
>>>> dereferencing type-punned pointer will break strict-aliasing rules
>>>> This appears to be the only aliasing related warning.
>>>
>>>
>>>> Olga
>>>> --
>>>>       ,   _                                    _   ,
>>>>      { \/`o;====-    Olga Kryzhanovska   -====;o`\/ }
>>>> .----'-/`-/     [email protected]   \-`\-'----.
>>>>  `'-..-| /       http://twitter.com/fleyta     \ |-..-'`
>>>>       /\/\     Solaris/BSD//C/C++ programmer   /\/\
>>>>       `--`                                      `--`
>>>
>>>
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>>>
>>
>>
>>
>
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-- 
      ,   _                                    _   ,
     { \/`o;====-    Olga Kryzhanovska   -====;o`\/ }
.----'-/`-/     [email protected]   \-`\-'----.
 `'-..-| /       http://twitter.com/fleyta     \ |-..-'`
      /\/\     Solaris/BSD//C/C++ programmer   /\/\
      `--`                                      `--`

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