[Insight-developers] CastImageFilterTest failures

[Luis Ibanez]

Cory, Bill,

One of the systems where this tests is failing is
zion.kitware. This is a 32bits system with gcc 4.4.

I just spent some quality time with the test, and it
seems that the failure only occurs when compiling
for Release.

The build for Debug, and the build without optimization
let the test pass.

--

Under Release the failure is quite curious because
if you repeat the check comparing the two float values
it returns alternatively true and false (as shown in the
attached code).

It looks like a bug of the compiler optimization.


I suggest that we use CMake property flags for
excluding this .cxx from optimization at compilation
time.


    Luis


-----------------------------------
On Fri, Jun 3, 2011 at 9:48 AM, Cory Quammen <cquammen at cs.unc.edu> wrote:
> Bill,
>
> This is a very strange problem on some systems. Somehow, the
> static_cast in the Cast functor in itkCastImageFilter.h produces
> different results than the static_cast in my test when casting from
> float to int.
>
> Basically, if you have
>
> int a = ...;
> float b = ...;
>
> b = static_cast< float >( a );
> b == static_cast< float >( a );
>
> the equality test in the last line of code can be false! This
> frightens and confuses me.
>
> My last change to the test fixed the error on MSVC by storing the
> static_cast result in a temporary variable and then doing an equality
> test between the temporary to the output of the CastImageFilter, but
> it obviously didn't fix it everywhere.
>
> I have no idea why the test is failing. Maybe one of the static_casts
> is casting from a higher-precision register than the other. I've
> Googled for similar problems reported elsewhere, but haven't found
> anything yet.
>
> For now, should I disable the float-to-int cast test to make the
> dashboard green?
>
> I have no idea why the test seems to be completely failing on SunOS.
>
> Gaetan,
>
> I'd be grateful if you could run the CastImageFilterTest in a debugger
> and send me the stack trace when it segfaults. To minimize the time
> you spend on this, the commands should be:
>
> cd $ITK_BUILD
> gdb bin/ITK-ImageFilterBaseTestDriver
> r itkCastImageFilterTest
>
> Thanks,
> Cory
>
>
> On Fri, Jun 3, 2011 at 8:35 AM, Bill Lorensen <bill.lorensen at gmail.com> wrote:
>> Cory,
>>
>> CastImageFilterTest is failing on 3 platforms:
>> http://www.cdash.org/CDash/testSummary.php?project=2&name=itkCastImageFilterTest&date=2011-06-03
>>
>> The two linux platforms are failing on
>> Casting from int to float ... [FAILED]
>>
>> The Sun system is seg faulting.
>>
>> Bill
>>
>
>
>
> --
> Cory Quammen
> Computer Integrated Systems for Microscopy and Manipulation (CISMM)
> Department of Computer Science
> University of North Carolina at Chapel Hill
> http://www.cs.unc.edu/~cquammen
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