[Bug regression/24565] New: facerec performance regression

["uttamp at us dot ibm dot com" <gcc-bugzilla at gcc dot gnu dot org>]

There has been a performance drop of approx. 8% in facerec benchmark with at
-O2 optimizatio level, since 2005-10-17 on ppc.

After doing little regression hunt, found following patch causing the drop,
http://gcc.gnu.org/ml/gcc-cvs/2005-10/msg00586.html

As this patch has two parts, one fixes bug #23714 and other removes the call to 
mark_array_ref_addressable() and related definitions.

As you can tell these two set of changes does two different things. First one
fixes pr #23714. 

I have verified that, the second set of changes causing the performance drop.
After reverting only the second part from the above patch and running facerec
benchmark at -O2, I could recover the old better numbers (~+8%).

Any thoughts on this?

I could revert the change (only second part) with the new patch unless there is
a reason (which for the moment I'm not able to understand) for removing the
call to mark_array_ref_addressable().


-- 
           Summary: facerec performance regression
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: regression
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: uttamp at us dot ibm dot com
 GCC build triplet: powerpc64-linux
  GCC host triplet: powerpc64-linux
GCC target triplet: powerpc64-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24565