[gdal-dev] Different results when reading a GeoTIFF with GDAL 2.1.2 vs 3.x

[Momtchil Momtchev]

     I get incorrect results with both of these images on 2 different 
machines both with AMD CPUs:

osgeo/gdal          latest                 7e049ed0255b        18 hours 
ago        1.15GB
osgeo/gdal          alpine-normal-v2.4.1   8ab6c3ea733b        8 months 
ago        154MB


     Those same docker images give correct results on an Intel CPU.

     I also tried GDAL 2.4.2 on OS X which is of course an Intel CPU and 
I get correct results, too.

     Is it possible that this is a compiler issue? Anyone else that can 
test this on an AMD CPU? Mine are old Phenom II X4 965s.

     2.1.2 is correct on both CPUs.


On 29/12/2019 19:27, Even Rouault wrote:
>>       I was stunned to discover a difference in the values of a GeoTIFF
>> file when read with GDAL 2.1.2 (official Debian stretch build) and GDAL
>> 3.1.0 (official Docker image)
> Which Docker image exactly ? With the ones of
> https://github.com/OSGeo/gdal/tree/master/gdal/docker , I get the same result
> as with 2.1.2:
>
> $ docker run --rm -v /home:/home osgeo/gdal gdalinfo --version
> GDAL 3.1.0dev-7652d752281951e989687c0270ce1c2d9b4219dd, released 2019/12/29
>
> $ docker run --rm -v /home:/home osgeo/gdal gdallocationinfo $PWD/2.tiff 9 0
> Report:
>    Location: (9P,0L)
>    Band 1:
>      Value: 16
>    Band 2:
>      Value: 130
>
>
> $ docker run --rm -v /home:/home osgeo/gdal gdallocationinfo $PWD/2.tiff 10 0
> Report:
>    Location: (10P,0L)
>    Band 1:
>      Value: 14
>    Band 2:
>      Value: 163
>
-- 
Momtchil Momtchev <momtchil at momtchev.com>