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

[Gabriel Dos_Reis]

| 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