Re: [PATCH for 7.2?] target/i386: Remove compilation errors when -Werror=maybe-uninitialized

[Eric Auger]

Hi Stefan,

On 12/7/22 16:55, Stefan Hajnoczi wrote:
> On Wed, 7 Dec 2022 at 09:34, Eric Auger <eric.auger@redhat.com> wrote:
>> Hi Stefan,
>>
>> On 12/7/22 15:09, Stefan Hajnoczi wrote:
>>> On Wed, 7 Dec 2022 at 08:31, Eric Auger <eric.auger@redhat.com> wrote:
>>>> On 12/7/22 14:24, Eric Auger wrote:
>>>>> Initialize r0-3 to avoid compilation errors when
>>>>> -Werror=maybe-uninitialized is used
>>>>>
>>>>> ../target/i386/ops_sse.h: In function ‘helper_vpermdq_ymm’:
>>>>> ../target/i386/ops_sse.h:2495:13: error: ‘r3’ may be used uninitialized 
>>>>> in this function [-Werror=maybe-uninitialized]
>>>>>  2495 |     d->Q(3) = r3;
>>>>>       |     ~~~~~~~~^~~~
>>>>> ../target/i386/ops_sse.h:2494:13: error: ‘r2’ may be used uninitialized 
>>>>> in this function [-Werror=maybe-uninitialized]
>>>>>  2494 |     d->Q(2) = r2;
>>>>>       |     ~~~~~~~~^~~~
>>>>> ../target/i386/ops_sse.h:2493:13: error: ‘r1’ may be used uninitialized 
>>>>> in this function [-Werror=maybe-uninitialized]
>>>>>  2493 |     d->Q(1) = r1;
>>>>>       |     ~~~~~~~~^~~~
>>>>> ../target/i386/ops_sse.h:2492:13: error: ‘r0’ may be used uninitialized 
>>>>> in this function [-Werror=maybe-uninitialized]
>>>>>  2492 |     d->Q(0) = r0;
>>>>>       |     ~~~~~~~~^~~~
>>>>>
>>>>> Signed-off-by: Eric Auger <eric.auger@redhat.com>
>>>>> Fixes: 790684776861 ("target/i386: reimplement 0x0f 0x3a, add AVX")
>>>>>
>>>>> ---
>>>>>
>>>>> Am I the only one getting this? Or anything wrong in my setup.
>>>> With Stefan's correct address. Forgive me for the noise.
>>> When is -Wmaybe-uninitialized used? QEMU's build system doesn't set
>>> it. Unless it's automatically set by meson this must be a manual
>>> --extra-cflags= option you set.
>> I am using this configure cmd line:
>>
>> ./configure --prefix=/usr --sysconfdir=/etc --libexecdir=/usr/lib/qemu
>> --target-list=x86_64-softmmu --docdir=/usr/share/doc/qemu --enable-kvm
>> --extra-cflags=-O --enable-trace-backends=log --python=/usr/bin/python3
>> --extra-cflags=-Wall --extra-cflags=-Wundef
>> --extra-cflags=-Wwrite-strings --extra-cflags=-Wmissing-prototypes
>> --extra-cflags=-fno-strict-aliasing --extra-cflags=-fno-common
>> --extra-cflags=-Werror=type-limits
>>> If you added it manually then let's fix this in 8.0 since it's not
>>> tested/supported and very few people will see this issue.
> Did you create the ./configure command-line manually? Do you think
> other people will hit this?
no I did not. I just tried to install a fresh qemu repo and just ran the
above configure command. You should be able to reproduce I think.

I am actually surprised nobody hit that already.

Thanks

Eric
>
> Stefan
>