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

[Matthias Klose <doko@cs.tu-berlin.de>]

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

From: Matthias Klose <doko@cs.tu-berlin.de>
To: Gabriel Dos_Reis <gdosreis@sophia.inria.fr>
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 23:28:20 +0100

 Gabriel Dos_Reis writes:
 > | 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.
 
 Thanks for the clarification, I did miss this information on the gnats
 report.