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Re: [PATCH v2] target/i386: Remove compilation errors when -Werror=maybe
From: |
Eric Auger |
Subject: |
Re: [PATCH v2] target/i386: Remove compilation errors when -Werror=maybe-uninitialized |
Date: |
Thu, 22 Dec 2022 11:07:31 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.3.1 |
Hi Philippe,
On 12/22/22 10:01, Philippe Mathieu-Daudé wrote:
> On 22/12/22 09:18, Paolo Bonzini wrote:
>> On 12/21/22 17:36, Eric Auger wrote:
>>> To avoid compilation errors when -Werror=maybe-uninitialized is used,
>>> replace 'case 3' by 'default'.
>>>
>>> Otherwise we get:
>>>
>>> ../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;
>>> | ~~~~~~~~^~~~
>
> With what compiler? Is that a supported one?
3aab489e-9d90-c1ad-0b6b-b2b5d80db723@redhat.com/">https://lore.kernel.org/qemu-devel/3aab489e-9d90-c1ad-0b6b-b2b5d80db723@redhat.com/
>
>>> Signed-off-by: Eric Auger <eric.auger@redhat.com>
>>> Suggested-by: Stefan Weil <sw@weilnetz.de>
>>> Fixes: 790684776861 ("target/i386: reimplement 0x0f 0x3a, add AVX")
>>> ---
>>> target/i386/ops_sse.h | 4 ++--
>>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/target/i386/ops_sse.h b/target/i386/ops_sse.h
>>> index 3cbc36a59d..c442c8c10c 100644
>>> --- a/target/i386/ops_sse.h
>>> +++ b/target/i386/ops_sse.h
>>> @@ -2466,7 +2466,7 @@ void helper_vpermdq_ymm(Reg *d, Reg *v, Reg
>>> *s, uint32_t order)
>>> r0 = s->Q(0);
>>> r1 = s->Q(1);
>>> break;
>>> - case 3:
>>> + default:
>>> r0 = s->Q(2);
>>> r1 = s->Q(3);
>>> break;
>>> @@ -2484,7 +2484,7 @@ void helper_vpermdq_ymm(Reg *d, Reg *v, Reg
>>> *s, uint32_t order)
>>> r2 = s->Q(0);
>>> r3 = s->Q(1);
>>> break;
>>> - case 3:
>>> + default:
>>> r2 = s->Q(2);
>>> r3 = s->Q(3);
>>> break;
>>
>> Queued, but this compiler sucks. :)
>
> Can't we simply add a dumb 'default' case? So when reviewing we don't
> have to evaluate 'default' means 3 here.
>
> -- >8 --
> --- a/target/i386/ops_sse.h
> +++ b/target/i386/ops_sse.h
> @@ -2470,6 +2470,8 @@ void helper_vpermdq_ymm(Reg *d, Reg *v, Reg *s,
> uint32_t order)
> r0 = s->Q(2);
> r1 = s->Q(3);
> break;
> + default:
> + qemu_build_not_reached();
> }
> switch ((order >> 4) & 3) {
> case 0:
> @@ -2488,6 +2490,8 @@ void helper_vpermdq_ymm(Reg *d, Reg *v, Reg *s,
> uint32_t order)
> r2 = s->Q(2);
> r3 = s->Q(3);
> break;
> + default:
> + qemu_build_not_reached();
> }
I guess this won't fix the fact r0, r1, r2, r3 are not initialized, will it?
Thanks
Eric
> d->Q(0) = r0;
> d->Q(1) = r1;
> ---
>
- [PATCH v2] target/i386: Remove compilation errors when -Werror=maybe-uninitialized, Eric Auger, 2022/12/21
- Re: [PATCH v2] target/i386: Remove compilation errors when -Werror=maybe-uninitialized, Stefan Weil, 2022/12/21
- Re: [PATCH v2] target/i386: Remove compilation errors when -Werror=maybe-uninitialized, Paolo Bonzini, 2022/12/22
- Re: [PATCH v2] target/i386: Remove compilation errors when -Werror=maybe-uninitialized, Philippe Mathieu-Daudé, 2022/12/22
- Re: [PATCH v2] target/i386: Remove compilation errors when -Werror=maybe-uninitialized,
Eric Auger <=
- Re: [PATCH v2] target/i386: Remove compilation errors when -Werror=maybe-uninitialized, Philippe Mathieu-Daudé, 2022/12/22
- Re: [PATCH v2] target/i386: Remove compilation errors when -Werror=maybe-uninitialized, Daniel P . Berrangé, 2022/12/22
- Re: [PATCH v2] target/i386: Remove compilation errors when -Werror=maybe-uninitialized, Eric Auger, 2022/12/22
- Re: [PATCH v2] target/i386: Remove compilation errors when -Werror=maybe-uninitialized, Philippe Mathieu-Daudé, 2022/12/22
- Re: [PATCH v2] target/i386: Remove compilation errors when -Werror=maybe-uninitialized, Stefan Weil, 2022/12/22
- Re: [PATCH v2] target/i386: Remove compilation errors when -Werror=maybe-uninitialized, Philippe Mathieu-Daudé, 2022/12/22
- Re: [PATCH v2] target/i386: Remove compilation errors when -Werror=maybe-uninitialized, Bernhard Beschow, 2022/12/22