Re: optimization/9279: [3.2 regression] [Sparc] combine bug

[Gabriel Dos_Reis <gdosreis@sophia.inria.fr>]

The following reply was made to PR optimization/9279; it has been noted by GNATS.

From: Gabriel Dos_Reis <gdosreis@sophia.inria.fr>
To: Matthias Klose <doko@cs.tu-berlin.de>
Cc: Eric Botcazou <ebotcazou@libertysurf.fr>, ebotcazou@gcc.gnu.org,
   frank@g-n-u.de, gcc-bugs@gcc.gnu.org, gcc-gnats@gcc.gnu.org
Subject: Re: optimization/9279: [3.2 regression] [Sparc] combine bug
Date: Tue, 28 Jan 2003 23:07:11 +0100 (MET)

 | Eric Botcazou writes:
 | > >     The fix introduces a performance regression for PowerPC (and possibly
 | > > other platforms) on the 3.2 branch.
 | > 
 | > Now reverted for this reason on the 3.2 branch so GCC 3.2.2 will ship with 
 | > the bug.
 | 
 | I see you having the choice between two regressions, one performance
 | regression (from 3.2.1 to 3.2.2) and one "wrong code" regression (from
 | 2.95 and 3.0.4 to 3.2.2). Not sure, if I should like your decision.
 
 As I explained to Eric, I would have been pleased to apply that
 patch.  However it turned out that it introduces (1) a performance
 regression; (2) possibly a wrong code generation -- David gave some
 references.  Therefore, to fix the new regressions we would have to grab 
 other patches not known to be safe.  The initial patch was beginning
 to have too much ramifications.  That is why I asked Eric to revert
 his patch.  
 
 I would suggest that, right after 3.2.2 release, interested parties
 investigate the issue and submit a complete patch which we would
 have sufficient time to test.
 
 -- Gaby