Experimental Physics and
Industrial Control System

Dirk Zimoch <[email protected]> · Mon, 27 Aug 2007 10:36:16 +0200

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

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System