Re: gcc 3.3 -03 produces bad code

[Daniel Jacobowitz <drow at mvista dot com>]

On Thu, Apr 17, 2003 at 09:32:23PM +0200, Ronald Kukuck wrote:
> Hello,
> 
> I'm using:
> 
> gcc version 3.3 20030226 (prerelease) (SuSE Linux)
> 
> A large application (~25MB), which worked fine with the gcc included
> in Suse 8.1, is now crashing in some modules if I compile it with "-O3".
> 
> I have tried to make the bug reproducible in a small file (test1.C).
> To see it working OK use:
> 
> g++ -O -o test test1.C
> 
> to see it fail use:
> 
> g++ -O3 -funroll-loops -mcpu=pentiumpro -o test test1.C
> 
> or use simply:
> 
> g++ -O3 -o test test1.C
> 
> which is producing different results then above one.
> 
> 
> Is there a workaround for this problem or is there a place where I can 
> download a new binary?

> inline int ReadDbRecHead(int *pred,int *succ,int *next, short *infopa, const int rec_no, const int dbunit) {
>       int *adress, *iptr;
>       
>      // DbsFindReadAdr(dbunit, rec_no);
>       adress = (int*)&s_in;
>       iptr=(int*)infopa;
>       *pred=*adress++;
>       *succ=*adress++;
>       *next=*adress++;
>       *iptr++=*adress++;
>       *iptr=*adress;
>       return(*adress);
>    }

You can't cast a short * to an int * that way.  I recommend searching
for information on type aliasing, or seeing the effect of
-fno-strict-aliasing on your code.


-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer