Re: bug in Red Hat Linux g++ 3.2.3

[Dirk Zimoch <dirk.zimoch@psi.ch>]

Hi

The bug also occurs with -O2, only -O1 is safe.
gcc 3.2.3 is the standard version on Scientific Linux 3, which we still 
have in use at the SLS. I would very much appreciate a workaround in the 
EPICS code.

Dirk

Jeff Hill wrote:
>  
>
> All,
>
>  
>
> There is a bug in Red Hat Linux g++ 3.2.3 when -O3 is specified that 
> causes CA R3.14.9 to fail. The bug is known not to occur with several 
> other g++ versions, but many versions have not been tested. I also don’t 
> know what versions of Linux g++ are most commonly used at the various 
> EPICS sites.
>
>  
>
> So I am curious if this is a substantial issue for the EPICS community 
> or if it can be safely ignored? If defective compilers are still in 
> widespread use I could look for a workaround in the EPICS source code.
>
>  
>
> Jeff
>
> During testing of R3.14.9 I see a bug showing up only in optimized 
> builds on Linux using g++ 3.2.3 that I don't see with other compilers. 
> This bug appears to be related to failure of this particular compiler to 
> follow the strict alias rules specified in the standard when optimizing 
> the byte swapping templates installed for R3.14.9.
>
> *Problems*
>
> Red hat Linux g++ 3.2.3 when -O3 is specified
>
> *No problems*
>
> mingw g++ 3.4.2 -O3
>
> Tornado 2.02 g++ -O2
>
> Microsoft C++ 2005 full optimization builds
>
>
> ______________________________________________________
> Jeffrey O. Hill           Internet     johill@lanl.gov 
> <mailto:johill@lanl.gov>
> LANL MS H820              Voice        505 665 1831
> Los Alamos NM 87545 USA   FAX          505 665 5107
>
>  

--
Dr. Dirk Zimoch
Paul Scherrer Institut, WBGB/006
5232 Villigen PSI, Switzerland
Phone +41 56 310 5182