[Development] Qt + GCC 6 no joy ?

Jürgen Hunold jhunold at gmx.eu
Thu May 19 21:08:48 CEST 2016

Hi Thiago,

Am Donnerstag, 19. Mai 2016, 10:58:24 CEST schrieb Thiago Macieira:
> On quinta-feira, 19 de maio de 2016 08:59:16 PDT Thiago Macieira wrote:
> > Backtrace with debugging symbols, but in release mode, is attached. I'll
> > try to study the generated code to see if I spot anything.
> -fno-delete-null-pointer-checks solves this problem. Of course, that doesn't
> explain where the issue is. I'll debug further later, after I figure out
> what's wrong with HiDPI -- after all, I can't debug if I can't read the
> text.

What about reading the gcc release notes?

From https://gcc.gnu.org/gcc-6/changes.html

"Value range propagation now assumes that the this pointer of C++ member 
functions is non-null. This eliminates common null pointer checks but also 
breaks some non-conforming code-bases (such as Qt-5, Chromium, KDevelop). As a 
temporary work-around -fno-delete-null-pointer-checks can be used. Wrong code 
can be identified by using -fsanitize=undefined."

I got this via https://blog.fefe.de/?ts=a9de792d (in german, unfortunately). 
So the rant there is for a limited audience...


* Dipl.-Math. Jürgen Hunold  ! 
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