Experimental Physics and
Industrial Control System

Hi Dirk,

Ernest indicated that this might be resolved by patching the compiler. If
that is possible then I am disinclined to create a workaround, but if not
then I will see what can be done.

Jeff

-----Original Message-----
From: Dirk Zimoch [mailto:[email protected]] 
Sent: Monday, August 27, 2007 2:36 AM
To: Jeff Hill
Cc: 'EPICS Tech Talk'
Subject: Re: bug in Red Hat Linux g++ 3.2.3

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     [email protected] 
> <mailto:[email protected]>
> 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

Replies:

Re: bug in Red Hat Linux g++ 3.2.3 Eric Norum

References:

bug in Red Hat Linux g++ 3.2.3 Jeff Hill

Re: bug in Red Hat Linux g++ 3.2.3 Dirk Zimoch

Navigate by Date:

Prev: Re: Port of EPICS 3.14.9 to ETRAX CRIS architecture - Strange Data Dirk Zimoch

Next: Re: Port of EPICS 3.14.9 to ETRAX CRIS architecture - Strange Data Andrew Johnson

Index: 1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006  <2007>  2008  2009  2010  2011  2012  2013  2014  2015  2016  2017  2018  2019  2020  2021  2022  2023  2024 

Navigate by Thread:

Prev: Re: bug in Red Hat Linux g++ 3.2.3 Dirk Zimoch

Next: Re: bug in Red Hat Linux g++ 3.2.3 Eric Norum

Index: 1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006  <2007>  2008  2009  2010  2011  2012  2013  2014  2015  2016  2017  2018  2019  2020  2021  2022  2023  2024