-O2 flag

[Serpent7776]

On Sat, 10 Jun 2017 21:05:01 -0300
Friedrich Locke <friedrich.locke at gmail.com> wrote:

> Here you have it:
> 
> gustav# cc --version
> FreeBSD clang version 3.8.0 (tags/RELEASE_380/final 262564) (based on 
> LLVM 3.8.0)
> Target: x86_64-unknown-freebsd11.0
> Thread model: posix
> InstalledDir: /usr/bin
> gustav#
This is not telling much. As pointed by Patrick this might be due to
uninitialized stack variables in a function.
You might want to try to:
- rebuild with enabled compiler warning flags (-W flags)
  https://clang.llvm.org/docs/DiagnosticsReference.html
- rebuild with sanitizer enabled
  https://clang.llvm.org/docs/UndefinedBehaviorSanitizer.html
- try running in debugger and find place where this error occurs
HTH


> Em 10/06/2017 18:09, Serpent7776 escreveu:
> > On Sat, 10 Jun 2017 16:20:25 -0300
> > Friedrich Locke <friedrich.locke at gmail.com> wrote:
> >  
> >> Hi folks,
> >>
> >> i am trying compile a program with cc on freebsd 11.
> >> When i use -O2 compilation flag, the compiled code is giving error on
> >> execution, but with i omit -O2 everything works ok.
> >>
> >> Have anybody already faced such problem ?  
> > Yes, a few times in the past. Your code may have hidden bug which is
> > triggered only with optimizations enabled. It might be relying on some kind
> > of undefined behaviour.
> > Unfortunately, I don't have any helpful advices on how to find this error -
> > try enabling all compiler warnings flags.
> > I'd suspect a bug in your code rather than a bug in compiler, but the
> > latter is not impossible.
> >  
> >> Thanks in advance.
> >> _______________________________________________
> >> freebsd-questions at freebsd.org mailing list
> >> https://lists.freebsd.org/mailman/listinfo/freebsd-questions
> >> To unsubscribe, send any mail to
> >> "freebsd-questions-unsubscribe at freebsd.org"  
> >
> >
> >  



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