qt4 broken on i686

[Jakub Bogusz]

On Wed, Aug 18, 2021 at 10:34:48PM +0200, Jan Rękorajski wrote:
> New builds of qt4 on i686 exhibit crashes (ex. linguist in avogadro), or
> infinite looping (ex. meinproc4 in kde4-kig).
> 
> I'm running out of ideas[1] and time to troubleshoot this and would
> appreciate if anyone would be willing to try and figure out WTF is
> broken there.
> 
> [1] neither -O0, nor -std=gnu98 seem to do the trick, it could be a
> glibc 2.34 issue, but I don't have resources at hand to validate it.

I don't know yet if it's related to glibc, gcc or binutils, but simple
testcase is searching in empty QMap:

```
#include <QtCore/QMap>

int main()
{
    QMap<int, std::string> mm;
    mm.constFind(999);
}
```

It hangs even on carme-x86_64.

Issue is probably related to shared_null static field (SIOF?)


-- 
Jakub Bogusz    http://qboosh.pl/