[Bug target/32523] disastrous scheduling for POWER5

["pinskia at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32523

--- Comment #13 from Andrew Pinski <pinskia at gcc dot gnu.org> 2010-09-29 23:20:29 UTC ---
(In reply to comment #12)
> Andrew,
> 
> I'm certainly unsurprised that you disagree with me, since I don't think we
> have ever agreed on anything in something like 5 years.  To get an idea of what
> I'm talking about, scope:
>    http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27827

And if you look at the history of those two bugs, you will notice I did not
close them as invalid at all.  I might have suggested they were but I never
closed them as such.  I had left them for people who would analysis them
better.  So you first said I marked it as invalid which was not true as the
history on the bug report does not lie.

For this bug, the problem of the first pass of the scheduler increases life
range of variables which causes the register allocator not to do a good job. 
There are other bugs which record that fact already too (I don't know them
currently but you can find them via searching for -fno-schedule-insns).  It is
a well known issue which has been improved.  Which I mentioned exactly in
comment #2.  Nobody might have tested your testcase again which is why someone
finally decided to ask you if you want to test it.  As I mentioned in this bug
report you were testing a heavily modified 3.3.3 (I know because unit-at-a-time
was included in SUSE's 3.3).