* [9fans] 6c bug?
@ 2012-02-28 4:40 erik quanstrom
2012-02-28 7:14 ` Bruce Ellis
[not found] ` <CAJQxxw=AN0dUGdu_sbdOc2Vkew3BXWPhvTOAxKKLgjHGxpxVjw@mail.gmail.c>
0 siblings, 2 replies; 5+ messages in thread
From: erik quanstrom @ 2012-02-28 4:40 UTC (permalink / raw)
To: 9fans
for p = uchar*, Nbus==256,
if((uint)p[1] >= Nbus){
generates
warning: ./mp.c:212 useless or misleading comparison: UCHAR >= 0x100
i'm pretty sure that 6c is incorrectly issuing the diagnostic before
applying the cast. (the cast is there to shut the compiler up.)
- erik
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [9fans] 6c bug?
2012-02-28 4:40 [9fans] 6c bug? erik quanstrom
@ 2012-02-28 7:14 ` Bruce Ellis
[not found] ` <CAJQxxw=AN0dUGdu_sbdOc2Vkew3BXWPhvTOAxKKLgjHGxpxVjw@mail.gmail.c>
1 sibling, 0 replies; 5+ messages in thread
From: Bruce Ellis @ 2012-02-28 7:14 UTC (permalink / raw)
To: Fans of the OS Plan 9 from Bell Labs
what values of p[1] do you expect the test to be of use?
On 28 February 2012 15:40, erik quanstrom <quanstro@quanstro.net> wrote:
> for p = uchar*, Nbus==256,
>
> if((uint)p[1] >= Nbus){
>
> generates
>
> warning: ./mp.c:212 useless or misleading comparison: UCHAR >= 0x100
>
> i'm pretty sure that 6c is incorrectly issuing the diagnostic before
> applying the cast. (the cast is there to shut the compiler up.)
>
> - erik
>
--
Don't meddle in the mouth -- MVS (0416935147, +1-513-3BRUCEE)
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [9fans] 6c bug?
[not found] ` <CAJQxxw=AN0dUGdu_sbdOc2Vkew3BXWPhvTOAxKKLgjHGxpxVjw@mail.gmail.c>
@ 2012-02-28 7:20 ` erik quanstrom
2012-02-28 9:22 ` Bruce Ellis
[not found] ` <CAJQxxwka-EGOgyTV-xBB1YOWTXLzyL=qtRWDkfz0NmD82koFpQ@mail.gmail.c>
0 siblings, 2 replies; 5+ messages in thread
From: erik quanstrom @ 2012-02-28 7:20 UTC (permalink / raw)
To: 9fans
On Tue Feb 28 02:16:04 EST 2012, bruce.ellis@gmail.com wrote:
> what values of p[1] do you expect the test to be of use?
>
> On 28 February 2012 15:40, erik quanstrom <quanstro@quanstro.net> wrote:
> > for p = uchar*, Nbus==256,
> >
> > if((uint)p[1] >= Nbus){
> >
> > generates
> >
> > warning: ./mp.c:212 useless or misleading comparison: UCHAR >= 0x100
> >
> > i'm pretty sure that 6c is incorrectly issuing the diagnostic before
> > applying the cast. (the cast is there to shut the compiler up.)
it is not a given that Nbus >= 255.
- erik
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [9fans] 6c bug?
2012-02-28 7:20 ` erik quanstrom
@ 2012-02-28 9:22 ` Bruce Ellis
[not found] ` <CAJQxxwka-EGOgyTV-xBB1YOWTXLzyL=qtRWDkfz0NmD82koFpQ@mail.gmail.c>
1 sibling, 0 replies; 5+ messages in thread
From: Bruce Ellis @ 2012-02-28 9:22 UTC (permalink / raw)
To: Fans of the OS Plan 9 from Bell Labs
for the example you gave the diagnostic is correct.
On 28 February 2012 18:20, erik quanstrom <quanstro@quanstro.net> wrote:
> On Tue Feb 28 02:16:04 EST 2012, bruce.ellis@gmail.com wrote:
>> what values of p[1] do you expect the test to be of use?
>>
>> On 28 February 2012 15:40, erik quanstrom <quanstro@quanstro.net> wrote:
>> > for p = uchar*, Nbus==256,
>> >
>> > if((uint)p[1] >= Nbus){
>> >
>> > generates
>> >
>> > warning: ./mp.c:212 useless or misleading comparison: UCHAR >= 0x100
>> >
>> > i'm pretty sure that 6c is incorrectly issuing the diagnostic before
>> > applying the cast. (the cast is there to shut the compiler up.)
>
> it is not a given that Nbus >= 255.
>
> - erik
>
--
Don't meddle in the mouth -- MVS (0416935147, +1-513-3BRUCEE)
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [9fans] 6c bug?
[not found] ` <CAJQxxwka-EGOgyTV-xBB1YOWTXLzyL=qtRWDkfz0NmD82koFpQ@mail.gmail.c>
@ 2012-02-28 18:37 ` erik quanstrom
0 siblings, 0 replies; 5+ messages in thread
From: erik quanstrom @ 2012-02-28 18:37 UTC (permalink / raw)
To: 9fans
On Tue Feb 28 04:23:56 EST 2012, bruce.ellis@gmail.com wrote:
> for the example you gave the diagnostic is correct.
pffft. you're right.
- erik
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2012-02-28 18:37 UTC | newest]
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2012-02-28 4:40 [9fans] 6c bug? erik quanstrom
2012-02-28 7:14 ` Bruce Ellis
[not found] ` <CAJQxxw=AN0dUGdu_sbdOc2Vkew3BXWPhvTOAxKKLgjHGxpxVjw@mail.gmail.c>
2012-02-28 7:20 ` erik quanstrom
2012-02-28 9:22 ` Bruce Ellis
[not found] ` <CAJQxxwka-EGOgyTV-xBB1YOWTXLzyL=qtRWDkfz0NmD82koFpQ@mail.gmail.c>
2012-02-28 18:37 ` erik quanstrom
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