recent KahanSum change causes a new test failure on ppc64le

[Stephan Bergmann]

On 9/7/23 08:25, Dan Horák wrote:
> On Thu, 7 Sep 2023 08:16:28 +0200
> Stephan Bergmann <sbergman at redhat.com> wrote:
>> On 9/5/23 18:53, Dan Horák wrote:
>>> seems the recent change [1] to KahanSum handling causes a test failure
>>> on ppc64le.
>>>
>>> Running scope as unit: -home-sharkcz-projects-libreoffice-workdir-CppunitTest-sc_statistical_functions_test.test:20230905152639:2378561.scope
>>> [_RUN_____] StatisticalFunctionsTest::testStatisticalFormulasFODS
>>> Testing load file:///home/sharkcz/projects/libreoffice//sc/qa/unit/data/functions/statistical/fods/KahanSum.fods:
>>> /home/sharkcz/projects/libreoffice/sc/qa/unit/functions_test.cxx:49:StatisticalFunctionsTest::testStatisticalFormulasFODS
>>> forced failure
>>> - Testing file:///home/sharkcz/projects/libreoffice//sc/qa/unit/data/functions/statistical/fods/KahanSum.fods failed, Sheet2.A90 '=SUM(F3:F102)' result: 6.6, expected: 5
>>
>> Interesting; I also saw that failure with my latest local build on macOS
>> aarch64 against Clang trunk.  (But didn't debug it further and wrote it
>> off as maybe some intermittent Clang trunk bug.)
>>
> 
> someone on IRC reported the same issue, also from macOS I believe

So, wild speculation, maybe it's a difference between x86-64 and all 
other architectures, given how that 
<https://gerrit.libreoffice.org/c/core/+/156253/> "Resolves: tdf#156985 
Treat adding two KahanSum differently" kept failing for (32-bit) 
<https://ci.libreoffice.org/job/gerrit_windows/> up until patch set 7. 
(And where patch set 8 reverted back to the original code for _WIN32, 
maybe in a misguided attempt to fix something that was seen failing on 
Windows 32-bit x86, but not known to (not) fail on Windows x86-64.)

Eike, any thoughts?