* [Bug 1881004] [NEW] fpu/softfloat.c: error: bitwise negation of a boolean expression
@ 2020-05-27 19:13 Philippe Mathieu-Daudé
2020-05-27 21:40 ` Peter Maydell
` (4 more replies)
0 siblings, 5 replies; 10+ messages in thread
From: Philippe Mathieu-Daudé @ 2020-05-27 19:13 UTC (permalink / raw)
To: qemu-devel
Public bug reported:
Last time I built QEMU was on commit d5c75ec500d96f1d93447f990cd5a4ef5ba27fae,
I just pulled to fea8f3ed739536fca027cf56af7f5576f37ef9cd and now get:
CC lm32-softmmu/fpu/softfloat.o
fpu/softfloat.c:3365:13: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
absZ &= ~ ( ( ( roundBits ^ 0x40 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3423:18: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
absZ0 &= ~ ( ( (uint64_t) ( absZ1<<1 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3483:18: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
absZ0 &= ~(((uint64_t)(absZ1<<1) == 0) & roundNearestEven);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3606:13: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
zSig &= ~ ( ( ( roundBits ^ 0x40 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3760:13: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
zSig &= ~ ( ( ( roundBits ^ 0x200 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3987:21: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
~ ( ( (uint64_t) ( zSig1<<1 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:4003:22: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
zSig0 &= ~ ( ( (uint64_t) ( zSig1<<1 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:4273:18: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
zSig1 &= ~ ( ( zSig2 + zSig2 == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
8 errors generated.
$ clang -v
clang version 10.0.0-4ubuntu1
Target: aarch64-unknown-linux-gnu
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 20.04 LTS
Release: 20.04
Codename: focal
** Affects: qemu
Importance: Undecided
Status: New
--
You received this bug notification because you are a member of qemu-
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https://bugs.launchpad.net/bugs/1881004
Title:
fpu/softfloat.c: error: bitwise negation of a boolean expression
Status in QEMU:
New
Bug description:
Last time I built QEMU was on commit d5c75ec500d96f1d93447f990cd5a4ef5ba27fae,
I just pulled to fea8f3ed739536fca027cf56af7f5576f37ef9cd and now get:
CC lm32-softmmu/fpu/softfloat.o
fpu/softfloat.c:3365:13: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
absZ &= ~ ( ( ( roundBits ^ 0x40 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3423:18: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
absZ0 &= ~ ( ( (uint64_t) ( absZ1<<1 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3483:18: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
absZ0 &= ~(((uint64_t)(absZ1<<1) == 0) & roundNearestEven);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3606:13: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
zSig &= ~ ( ( ( roundBits ^ 0x40 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3760:13: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
zSig &= ~ ( ( ( roundBits ^ 0x200 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3987:21: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
~ ( ( (uint64_t) ( zSig1<<1 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:4003:22: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
zSig0 &= ~ ( ( (uint64_t) ( zSig1<<1 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:4273:18: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
zSig1 &= ~ ( ( zSig2 + zSig2 == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
8 errors generated.
$ clang -v
clang version 10.0.0-4ubuntu1
Target: aarch64-unknown-linux-gnu
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 20.04 LTS
Release: 20.04
Codename: focal
To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1881004/+subscriptions
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [Bug 1881004] [NEW] fpu/softfloat.c: error: bitwise negation of a boolean expression
@ 2020-05-27 21:40 ` Peter Maydell
0 siblings, 0 replies; 10+ messages in thread
From: Peter Maydell @ 2020-05-27 21:40 UTC (permalink / raw)
To: Bug 1881004; +Cc: QEMU Developers
On Wed, 27 May 2020 at 20:21, Philippe Mathieu-Daudé
<1881004@bugs.launchpad.net> wrote:
>
> Public bug reported:
>
> Last time I built QEMU was on commit d5c75ec500d96f1d93447f990cd5a4ef5ba27fae,
> I just pulled to fea8f3ed739536fca027cf56af7f5576f37ef9cd and now get:
>
> CC lm32-softmmu/fpu/softfloat.o
> fpu/softfloat.c:3365:13: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
> absZ &= ~ ( ( ( roundBits ^ 0x40 ) == 0 ) & roundNearestEven );
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> !
"(x & y)" is not a boolean expression, so we should report this to clang
as a bug (I assume what they actually are trying to complain about is
bitwise AND with a boolean expression).
thanks
-- PMM
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [Bug 1881004] [NEW] fpu/softfloat.c: error: bitwise negation of a boolean expression
@ 2020-05-27 21:40 ` Peter Maydell
0 siblings, 0 replies; 10+ messages in thread
From: Peter Maydell @ 2020-05-27 21:40 UTC (permalink / raw)
To: qemu-devel
On Wed, 27 May 2020 at 20:21, Philippe Mathieu-Daudé
<1881004@bugs.launchpad.net> wrote:
>
> Public bug reported:
>
> Last time I built QEMU was on commit d5c75ec500d96f1d93447f990cd5a4ef5ba27fae,
> I just pulled to fea8f3ed739536fca027cf56af7f5576f37ef9cd and now get:
>
> CC lm32-softmmu/fpu/softfloat.o
> fpu/softfloat.c:3365:13: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
> absZ &= ~ ( ( ( roundBits ^ 0x40 ) == 0 ) & roundNearestEven );
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> !
"(x & y)" is not a boolean expression, so we should report this to clang
as a bug (I assume what they actually are trying to complain about is
bitwise AND with a boolean expression).
thanks
-- PMM
--
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1881004
Title:
fpu/softfloat.c: error: bitwise negation of a boolean expression
Status in QEMU:
New
Bug description:
Last time I built QEMU was on commit d5c75ec500d96f1d93447f990cd5a4ef5ba27fae,
I just pulled to fea8f3ed739536fca027cf56af7f5576f37ef9cd and now get:
CC lm32-softmmu/fpu/softfloat.o
fpu/softfloat.c:3365:13: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
absZ &= ~ ( ( ( roundBits ^ 0x40 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3423:18: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
absZ0 &= ~ ( ( (uint64_t) ( absZ1<<1 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3483:18: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
absZ0 &= ~(((uint64_t)(absZ1<<1) == 0) & roundNearestEven);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3606:13: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
zSig &= ~ ( ( ( roundBits ^ 0x40 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3760:13: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
zSig &= ~ ( ( ( roundBits ^ 0x200 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3987:21: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
~ ( ( (uint64_t) ( zSig1<<1 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:4003:22: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
zSig0 &= ~ ( ( (uint64_t) ( zSig1<<1 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:4273:18: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
zSig1 &= ~ ( ( zSig2 + zSig2 == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
8 errors generated.
$ clang -v
clang version 10.0.0-4ubuntu1
Target: aarch64-unknown-linux-gnu
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 20.04 LTS
Release: 20.04
Codename: focal
To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1881004/+subscriptions
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [Bug 1881004] [NEW] fpu/softfloat.c: error: bitwise negation of a boolean expression
@ 2020-05-27 21:54 ` Eric Blake
0 siblings, 0 replies; 10+ messages in thread
From: Eric Blake @ 2020-05-27 21:54 UTC (permalink / raw)
To: Peter Maydell, Bug 1881004; +Cc: QEMU Developers
On 5/27/20 4:40 PM, Peter Maydell wrote:
> On Wed, 27 May 2020 at 20:21, Philippe Mathieu-Daudé
> <1881004@bugs.launchpad.net> wrote:
>>
>> Public bug reported:
>>
>> Last time I built QEMU was on commit d5c75ec500d96f1d93447f990cd5a4ef5ba27fae,
>> I just pulled to fea8f3ed739536fca027cf56af7f5576f37ef9cd and now get:
>>
>> CC lm32-softmmu/fpu/softfloat.o
>> fpu/softfloat.c:3365:13: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
>> absZ &= ~ ( ( ( roundBits ^ 0x40 ) == 0 ) & roundNearestEven );
>> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> !
>
>
> "(x & y)" is not a boolean expression, so we should report this to clang
> as a bug (I assume what they actually are trying to complain about is
> bitwise AND with a boolean expression).
We have:
uint64_t &= ~ ( ( ( int8_t ^ int ) == int ) & bool )
which is
uint64_t &= ~ ( bool & bool )
which is then
uint64_t &= ~ ( int )
resulting in one of:
uint64_t &= 0xffffffffffffffff
uint64_t &= 0xfffffffffffffffe
It is a very odd way of stating that 'if this condition is true, mask
out the least-significant-bit'. In general, 'bool & bool' is used where
the side-effect-skipping 'bool && bool' is inappropriate; I'm a bit
surprised that clang is not questioning whether we meant '&&' instead of
'&' (the two operators give the same effect in this case).
You are right that clang is fishy for calling it logical negation of a
bool, when it is really logical negation of an int, but we are also
fishy in that we are using bitwise AND of two bools as an int in the
first place.
Regardless of whether clang changes, would it be better to write the
code as:
if (((roundBits ^ 0x40) == 0) && roundNearestEven) {
absZ &= ~1;
}
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3226
Virtualization: qemu.org | libvirt.org
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [Bug 1881004] [NEW] fpu/softfloat.c: error: bitwise negation of a boolean expression
@ 2020-05-27 21:54 ` Eric Blake
0 siblings, 0 replies; 10+ messages in thread
From: Eric Blake @ 2020-05-27 21:54 UTC (permalink / raw)
To: qemu-devel
On 5/27/20 4:40 PM, Peter Maydell wrote:
> On Wed, 27 May 2020 at 20:21, Philippe Mathieu-Daudé
> <1881004@bugs.launchpad.net> wrote:
>>
>> Public bug reported:
>>
>> Last time I built QEMU was on commit d5c75ec500d96f1d93447f990cd5a4ef5ba27fae,
>> I just pulled to fea8f3ed739536fca027cf56af7f5576f37ef9cd and now get:
>>
>> CC lm32-softmmu/fpu/softfloat.o
>> fpu/softfloat.c:3365:13: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
>> absZ &= ~ ( ( ( roundBits ^ 0x40 ) == 0 ) & roundNearestEven );
>> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> !
>
>
> "(x & y)" is not a boolean expression, so we should report this to clang
> as a bug (I assume what they actually are trying to complain about is
> bitwise AND with a boolean expression).
We have:
uint64_t &= ~ ( ( ( int8_t ^ int ) == int ) & bool )
which is
uint64_t &= ~ ( bool & bool )
which is then
uint64_t &= ~ ( int )
resulting in one of:
uint64_t &= 0xffffffffffffffff
uint64_t &= 0xfffffffffffffffe
It is a very odd way of stating that 'if this condition is true, mask
out the least-significant-bit'. In general, 'bool & bool' is used where
the side-effect-skipping 'bool && bool' is inappropriate; I'm a bit
surprised that clang is not questioning whether we meant '&&' instead of
'&' (the two operators give the same effect in this case).
You are right that clang is fishy for calling it logical negation of a
bool, when it is really logical negation of an int, but we are also
fishy in that we are using bitwise AND of two bools as an int in the
first place.
Regardless of whether clang changes, would it be better to write the
code as:
if (((roundBits ^ 0x40) == 0) && roundNearestEven) {
absZ &= ~1;
}
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3226
Virtualization: qemu.org | libvirt.org
--
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1881004
Title:
fpu/softfloat.c: error: bitwise negation of a boolean expression
Status in QEMU:
New
Bug description:
Last time I built QEMU was on commit d5c75ec500d96f1d93447f990cd5a4ef5ba27fae,
I just pulled to fea8f3ed739536fca027cf56af7f5576f37ef9cd and now get:
CC lm32-softmmu/fpu/softfloat.o
fpu/softfloat.c:3365:13: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
absZ &= ~ ( ( ( roundBits ^ 0x40 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3423:18: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
absZ0 &= ~ ( ( (uint64_t) ( absZ1<<1 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3483:18: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
absZ0 &= ~(((uint64_t)(absZ1<<1) == 0) & roundNearestEven);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3606:13: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
zSig &= ~ ( ( ( roundBits ^ 0x40 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3760:13: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
zSig &= ~ ( ( ( roundBits ^ 0x200 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3987:21: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
~ ( ( (uint64_t) ( zSig1<<1 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:4003:22: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
zSig0 &= ~ ( ( (uint64_t) ( zSig1<<1 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:4273:18: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
zSig1 &= ~ ( ( zSig2 + zSig2 == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
8 errors generated.
$ clang -v
clang version 10.0.0-4ubuntu1
Target: aarch64-unknown-linux-gnu
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 20.04 LTS
Release: 20.04
Codename: focal
To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1881004/+subscriptions
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [Bug 1881004] [NEW] fpu/softfloat.c: error: bitwise negation of a boolean expression
2020-05-27 21:54 ` Eric Blake
(?)
@ 2020-05-28 6:20 ` Thomas Huth
-1 siblings, 0 replies; 10+ messages in thread
From: Thomas Huth @ 2020-05-28 6:20 UTC (permalink / raw)
To: Eric Blake, Peter Maydell, Bug 1881004; +Cc: QEMU Developers
On 27/05/2020 23.54, Eric Blake wrote:
> On 5/27/20 4:40 PM, Peter Maydell wrote:
>> On Wed, 27 May 2020 at 20:21, Philippe Mathieu-Daudé
>> <1881004@bugs.launchpad.net> wrote:
>>>
>>> Public bug reported:
>>>
>>> Last time I built QEMU was on commit
>>> d5c75ec500d96f1d93447f990cd5a4ef5ba27fae,
>>> I just pulled to fea8f3ed739536fca027cf56af7f5576f37ef9cd and now get:
>>>
>>> CC lm32-softmmu/fpu/softfloat.o
>>> fpu/softfloat.c:3365:13: error: bitwise negation of a boolean
>>> expression; did you mean logical negation? [-Werror,-Wbool-operation]
>>> absZ &= ~ ( ( ( roundBits ^ 0x40 ) == 0 ) & roundNearestEven );
>>> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>> !
>>
>>
>> "(x & y)" is not a boolean expression, so we should report this to clang
>> as a bug (I assume what they actually are trying to complain about is
>> bitwise AND with a boolean expression).
>
> We have:
>
> uint64_t &= ~ ( ( ( int8_t ^ int ) == int ) & bool )
>
> which is
>
> uint64_t &= ~ ( bool & bool )
>
> which is then
>
> uint64_t &= ~ ( int )
>
> resulting in one of:
>
> uint64_t &= 0xffffffffffffffff
> uint64_t &= 0xfffffffffffffffe
>
> It is a very odd way of stating that 'if this condition is true, mask
> out the least-significant-bit'. In general, 'bool & bool' is used where
> the side-effect-skipping 'bool && bool' is inappropriate; I'm a bit
> surprised that clang is not questioning whether we meant '&&' instead of
> '&' (the two operators give the same effect in this case).
>
> You are right that clang is fishy for calling it logical negation of a
> bool, when it is really logical negation of an int, but we are also
> fishy in that we are using bitwise AND of two bools as an int in the
> first place.
>
> Regardless of whether clang changes, would it be better to write the
> code as:
>
> if (((roundBits ^ 0x40) == 0) && roundNearestEven) {
> absZ &= ~1;
> }
I agree, that's also much better to read.
And FWIW, WinUAE fixed a similar problem in the same way recently:
https://github.com/tonioni/WinUAE/commit/51f5e7bfc39cf37daf7283
So I think this is the right way to go. Could you send your suggestion
as a proper patch?
Thanks,
Thomas
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug 1881004] Re: fpu/softfloat.c: error: bitwise negation of a boolean expression
2020-05-27 19:13 [Bug 1881004] [NEW] fpu/softfloat.c: error: bitwise negation of a boolean expression Philippe Mathieu-Daudé
2020-05-27 21:40 ` Peter Maydell
@ 2020-05-28 9:28 ` Philippe Mathieu-Daudé
2020-06-08 7:17 ` Philippe Mathieu-Daudé
` (2 subsequent siblings)
4 siblings, 0 replies; 10+ messages in thread
From: Philippe Mathieu-Daudé @ 2020-05-28 9:28 UTC (permalink / raw)
To: qemu-devel
Patch sent:
https://lists.gnu.org/archive/html/qemu-devel/2020-05/msg07861.html
--
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1881004
Title:
fpu/softfloat.c: error: bitwise negation of a boolean expression
Status in QEMU:
New
Bug description:
Last time I built QEMU was on commit d5c75ec500d96f1d93447f990cd5a4ef5ba27fae,
I just pulled to fea8f3ed739536fca027cf56af7f5576f37ef9cd and now get:
CC lm32-softmmu/fpu/softfloat.o
fpu/softfloat.c:3365:13: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
absZ &= ~ ( ( ( roundBits ^ 0x40 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3423:18: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
absZ0 &= ~ ( ( (uint64_t) ( absZ1<<1 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3483:18: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
absZ0 &= ~(((uint64_t)(absZ1<<1) == 0) & roundNearestEven);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3606:13: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
zSig &= ~ ( ( ( roundBits ^ 0x40 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3760:13: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
zSig &= ~ ( ( ( roundBits ^ 0x200 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3987:21: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
~ ( ( (uint64_t) ( zSig1<<1 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:4003:22: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
zSig0 &= ~ ( ( (uint64_t) ( zSig1<<1 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:4273:18: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
zSig1 &= ~ ( ( zSig2 + zSig2 == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
8 errors generated.
$ clang -v
clang version 10.0.0-4ubuntu1
Target: aarch64-unknown-linux-gnu
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 20.04 LTS
Release: 20.04
Codename: focal
To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1881004/+subscriptions
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug 1881004] Re: fpu/softfloat.c: error: bitwise negation of a boolean expression
2020-05-27 19:13 [Bug 1881004] [NEW] fpu/softfloat.c: error: bitwise negation of a boolean expression Philippe Mathieu-Daudé
2020-05-27 21:40 ` Peter Maydell
2020-05-28 9:28 ` [Bug 1881004] " Philippe Mathieu-Daudé
@ 2020-06-08 7:17 ` Philippe Mathieu-Daudé
2020-07-20 16:27 ` Peter Maydell
2020-08-20 15:09 ` Thomas Huth
4 siblings, 0 replies; 10+ messages in thread
From: Philippe Mathieu-Daudé @ 2020-06-08 7:17 UTC (permalink / raw)
To: qemu-devel
** Changed in: qemu
Status: New => In Progress
--
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1881004
Title:
fpu/softfloat.c: error: bitwise negation of a boolean expression
Status in QEMU:
In Progress
Bug description:
Last time I built QEMU was on commit d5c75ec500d96f1d93447f990cd5a4ef5ba27fae,
I just pulled to fea8f3ed739536fca027cf56af7f5576f37ef9cd and now get:
CC lm32-softmmu/fpu/softfloat.o
fpu/softfloat.c:3365:13: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
absZ &= ~ ( ( ( roundBits ^ 0x40 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3423:18: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
absZ0 &= ~ ( ( (uint64_t) ( absZ1<<1 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3483:18: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
absZ0 &= ~(((uint64_t)(absZ1<<1) == 0) & roundNearestEven);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3606:13: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
zSig &= ~ ( ( ( roundBits ^ 0x40 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3760:13: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
zSig &= ~ ( ( ( roundBits ^ 0x200 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3987:21: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
~ ( ( (uint64_t) ( zSig1<<1 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:4003:22: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
zSig0 &= ~ ( ( (uint64_t) ( zSig1<<1 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:4273:18: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
zSig1 &= ~ ( ( zSig2 + zSig2 == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
8 errors generated.
$ clang -v
clang version 10.0.0-4ubuntu1
Target: aarch64-unknown-linux-gnu
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 20.04 LTS
Release: 20.04
Codename: focal
To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1881004/+subscriptions
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug 1881004] Re: fpu/softfloat.c: error: bitwise negation of a boolean expression
2020-05-27 19:13 [Bug 1881004] [NEW] fpu/softfloat.c: error: bitwise negation of a boolean expression Philippe Mathieu-Daudé
` (2 preceding siblings ...)
2020-06-08 7:17 ` Philippe Mathieu-Daudé
@ 2020-07-20 16:27 ` Peter Maydell
2020-08-20 15:09 ` Thomas Huth
4 siblings, 0 replies; 10+ messages in thread
From: Peter Maydell @ 2020-07-20 16:27 UTC (permalink / raw)
To: qemu-devel
Fixed in commit 4066288694c3bdd175df8, which will be in 5.1.
** Changed in: qemu
Status: In Progress => Fix Committed
--
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1881004
Title:
fpu/softfloat.c: error: bitwise negation of a boolean expression
Status in QEMU:
Fix Committed
Bug description:
Last time I built QEMU was on commit d5c75ec500d96f1d93447f990cd5a4ef5ba27fae,
I just pulled to fea8f3ed739536fca027cf56af7f5576f37ef9cd and now get:
CC lm32-softmmu/fpu/softfloat.o
fpu/softfloat.c:3365:13: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
absZ &= ~ ( ( ( roundBits ^ 0x40 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3423:18: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
absZ0 &= ~ ( ( (uint64_t) ( absZ1<<1 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3483:18: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
absZ0 &= ~(((uint64_t)(absZ1<<1) == 0) & roundNearestEven);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3606:13: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
zSig &= ~ ( ( ( roundBits ^ 0x40 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3760:13: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
zSig &= ~ ( ( ( roundBits ^ 0x200 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3987:21: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
~ ( ( (uint64_t) ( zSig1<<1 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:4003:22: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
zSig0 &= ~ ( ( (uint64_t) ( zSig1<<1 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:4273:18: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
zSig1 &= ~ ( ( zSig2 + zSig2 == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
8 errors generated.
$ clang -v
clang version 10.0.0-4ubuntu1
Target: aarch64-unknown-linux-gnu
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 20.04 LTS
Release: 20.04
Codename: focal
To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1881004/+subscriptions
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug 1881004] Re: fpu/softfloat.c: error: bitwise negation of a boolean expression
2020-05-27 19:13 [Bug 1881004] [NEW] fpu/softfloat.c: error: bitwise negation of a boolean expression Philippe Mathieu-Daudé
` (3 preceding siblings ...)
2020-07-20 16:27 ` Peter Maydell
@ 2020-08-20 15:09 ` Thomas Huth
4 siblings, 0 replies; 10+ messages in thread
From: Thomas Huth @ 2020-08-20 15:09 UTC (permalink / raw)
To: qemu-devel
** Changed in: qemu
Status: Fix Committed => Fix Released
--
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1881004
Title:
fpu/softfloat.c: error: bitwise negation of a boolean expression
Status in QEMU:
Fix Released
Bug description:
Last time I built QEMU was on commit d5c75ec500d96f1d93447f990cd5a4ef5ba27fae,
I just pulled to fea8f3ed739536fca027cf56af7f5576f37ef9cd and now get:
CC lm32-softmmu/fpu/softfloat.o
fpu/softfloat.c:3365:13: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
absZ &= ~ ( ( ( roundBits ^ 0x40 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3423:18: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
absZ0 &= ~ ( ( (uint64_t) ( absZ1<<1 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3483:18: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
absZ0 &= ~(((uint64_t)(absZ1<<1) == 0) & roundNearestEven);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3606:13: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
zSig &= ~ ( ( ( roundBits ^ 0x40 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3760:13: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
zSig &= ~ ( ( ( roundBits ^ 0x200 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:3987:21: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
~ ( ( (uint64_t) ( zSig1<<1 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:4003:22: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
zSig0 &= ~ ( ( (uint64_t) ( zSig1<<1 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
fpu/softfloat.c:4273:18: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
zSig1 &= ~ ( ( zSig2 + zSig2 == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
8 errors generated.
$ clang -v
clang version 10.0.0-4ubuntu1
Target: aarch64-unknown-linux-gnu
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 20.04 LTS
Release: 20.04
Codename: focal
To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1881004/+subscriptions
^ permalink raw reply [flat|nested] 10+ messages in thread
end of thread, other threads:[~2020-08-20 15:26 UTC | newest]
Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-05-27 19:13 [Bug 1881004] [NEW] fpu/softfloat.c: error: bitwise negation of a boolean expression Philippe Mathieu-Daudé
2020-05-27 21:40 ` Peter Maydell
2020-05-27 21:40 ` Peter Maydell
2020-05-27 21:54 ` Eric Blake
2020-05-27 21:54 ` Eric Blake
2020-05-28 6:20 ` Thomas Huth
2020-05-28 9:28 ` [Bug 1881004] " Philippe Mathieu-Daudé
2020-06-08 7:17 ` Philippe Mathieu-Daudé
2020-07-20 16:27 ` Peter Maydell
2020-08-20 15:09 ` Thomas Huth
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