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List: wine-devel
Subject: Re: [PATCH 1/6] dlls/msvcrt*: ensure variable sse2_cw is set for all code paths in _control87 (GCC11
From: Eric Pouech <eric.pouech () orange ! fr>
Date: 2021-09-30 17:56:52
Message-ID: ba6a6a24-cd5c-d066-8239-ed24e11210ac () orange ! fr
[Download RAW message or body]
Le 30/09/2021 à 19:39, Zebediah Figura a écrit :
> On 9/30/21 12:14 PM, Eric Pouech wrote:
>>
>>>>
>>>> which still gives me the warnings, when compiling the 32bit part of a
>>>> wow64 conf
>>>>
>>>> (but not on a pure 32bit conf)
>>>>
>>>> your solution doesn't generate warnings on neither of the two
>>>>
>>>> so will need further investigation on:
>>>>
>>>> - discrepency wrt wow
>>>>
>>>> - why the difference between the two patches
>>>
>>> I don't get warnings with that diff either. What version of GCC do you
>>> have?
>>
>> well, o well....
>>
>> retesting today, and couldn't get any warnings with the patch I posted
>> yesterday...<grrr>
>>
>>
>> moreover, in this patch, if I change the if (_control... by if
>> (!control... (inverting the test), I get no warnings either which makes
>> absolutely no sense
>>
>>
>> I'm starting to wonder if the -Wmaybe-uninitialized warning could be a
>> little fragile at this point
>>
>>
>> there are a couple of bugs reports on gcc bugzilla reguarding this
>> warning
>>
>> potentially bugs report like may link to the same type of issues
>>
>> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102381
>>
>> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101768
>>
>>
>> I may wait a bit to let things settle down before taking any action on
>> this fix in msvcrt
>
> I mean, -Wmaybe-uninitialized has always been at least somewhat
> heuristic, throughout the entire history of gcc, and there have been
> false positives and false negatives. But I've found that it tends to
> behave nicely for idiomatically structured code. I've found very few
> cases where "just initialize the variable to zero" seems like the best
> solution to me.
I'm not suggesting at this point to disable -Wmaybe-unitialized
I'm just facing instability in tests results here:
- either because of me
- hw instability (i've seen some abnormal crashes)
- heisenbug in gcc
(listed in decreasing probability)
A+
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<div class="moz-cite-prefix">Le 30/09/2021 à 19:39, Zebediah Figura
a écrit :<br>
</div>
<blockquote type="cite"
cite="mid:fc7b08dc-7295-ca03-a2ac-55a1d300a55e@codeweavers.com">On
9/30/21 12:14 PM, Eric Pouech wrote:
<br>
<blockquote type="cite">
<br>
<blockquote type="cite">
<blockquote type="cite">
<br>
which still gives me the warnings, when compiling the 32bit
part of a
<br>
wow64 conf
<br>
<br>
(but not on a pure 32bit conf)
<br>
<br>
your solution doesn't generate warnings on neither of the
two
<br>
<br>
so will need further investigation on:
<br>
<br>
- discrepency wrt wow
<br>
<br>
- why the difference between the two patches
<br>
</blockquote>
<br>
I don't get warnings with that diff either. What version of
GCC do you
<br>
have?
<br>
</blockquote>
<br>
well, o well....
<br>
<br>
retesting today, and couldn't get any warnings with the patch I
posted
<br>
yesterday...<grrr>
<br>
<br>
<br>
moreover, in this patch, if I change the if (_control... by if
<br>
(!control... (inverting the test), I get no warnings either
which makes
<br>
absolutely no sense
<br>
<br>
<br>
I'm starting to wonder if the -Wmaybe-uninitialized warning
could be a
<br>
little fragile at this point
<br>
<br>
<br>
there are a couple of bugs reports on gcc bugzilla reguarding
this warning
<br>
<br>
potentially bugs report like may link to the same type of issues
<br>
<br>
<a class="moz-txt-link-freetext" \
href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102381">https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102381</a>
<br>
<br>
<a class="moz-txt-link-freetext" \
href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101768">https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101768</a>
<br>
<br>
<br>
I may wait a bit to let things settle down before taking any
action on
<br>
this fix in msvcrt
<br>
</blockquote>
<br>
I mean, -Wmaybe-uninitialized has always been at least somewhat
heuristic, throughout the entire history of gcc, and there have
been false positives and false negatives. But I've found that it
tends to behave nicely for idiomatically structured code. I've
found very few cases where "just initialize the variable to zero"
seems like the best solution to me.
<br>
</blockquote>
<p><font face="Helvetica, Arial, sans-serif">I'm not suggesting at
this point to disable -Wmaybe-unitialized</font></p>
<p><font face="Helvetica, Arial, sans-serif">I'm just facing
instability in tests results here:</font></p>
<p><font face="Helvetica, Arial, sans-serif">- either because of me</font></p>
<p><font face="Helvetica, Arial, sans-serif">- hw instability (i've
seen some abnormal crashes)<br>
</font></p>
<p><font face="Helvetica, Arial, sans-serif">- heisenbug in gcc</font></p>
<p><font face="Helvetica, Arial, sans-serif">(listed in decreasing
probability)</font></p>
<p><font face="Helvetica, Arial, sans-serif">A+</font><br>
</p>
</body>
</html>
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