c++/8543: bus error with 2 word alignments

[Wolfgang Bangerth]

The following reply was made to PR c++/8543; it has been noted by GNATS.

From: Wolfgang Bangerth <bangerth@ticam.utexas.edu>
To: Massimo Ravasi <massimo.ravasi@epfl.ch>
Cc: gcc-gnats@gcc.gnu.org
Subject: RE: c++/8543: bus error with 2 word alignments
Date: Tue, 19 Nov 2002 09:25:53 -0600 (CST)

 Massimo,
 alignment issues are generally something that differs between processors 
 and operating systems. Some processors cannot load doubles that are not 
 aligned, some can. The same may apply to long long data types, but the 
 alignment requirements of types of the same length are not necessarily 
 the same. If a processor is told to load data from an address that is not 
 properly aligned, it will generate a bus error. This is what you are seeing.
 Since alignment issues are platform dependent, it is only sensible to have 
 the flag you describe on certain platforms only.
 
 This being said, since I don't know the requirements SunOS/SPARC has on 
 long long data types, I cannot help you more on this. Some Sparc 
 maintainer would have to help out here. Accessing data at a lower 
 alignment is certainly suspicious.
 
 Regards
   Wolfgang
 
 -------------------------------------------------------------------------
 Wolfgang Bangerth              email:           bangerth@ticam.utexas.edu
                                www: http://www.ticam.utexas.edu/~bangerth