[Bug middle-end/24408] New: [4.1 Regression] Invariant code no longer removed from loop when doing FDO.

[steinmtz at us dot ibm dot com]

There was some discussion on the GCC mailing list in late August, early
September about a performance regression caused by the disabling of the old
loop optimizer when doing FDO.

http://gcc.gnu.org/ml/gcc/2005-08/msg00899.html

Loop invariant motions done by the old loop optimizer no longer occur.  This is
causing a performance regression on some benchmarks.

The following patch enables loop invariant motions during FDO and fixes the
observed performance regression:

http://gcc.gnu.org/ml/gcc-patches/2005-10/msg00224.html


-- 
           Summary: [4.1 Regression] Invariant code no longer removed from
                    loop when doing FDO.
           Product: gcc
           Version: 4.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: middle-end
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: steinmtz at us dot ibm dot com
  GCC host triplet: powerpc64-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24408